**APPENDIX A**

**PHILOSOPHICAL AND OPERATIONAL GUIDELINES FOR DEVELOPING A NORTH
AMERICAN SCIENCE-LANGUAGE STANDARD FOR DIGITAL GEOLOGIC-MAP DATABASES**

North American Geologic-Map Data Model Steering Committee

**Science Language Technical Team (SLTT)**

This document should be cited as:

North American Geologic-Map Data Model Science Language Technical Team,
2004, Report on progress to develop a North American science-language
standard for digital geologic-map databases; Appendix A\--Philosophical
and operational guidelines for developing a North American
science-language standard for digital geologic-map databases, Version
1.0 (12/18/2004), *in* Soller, D.R., ed., Digital Mapping Techniques
'04---Workshop Proceedings: U.S. Geological Survey Open-File Report
2004-1451, 61 p. Appendix A accessed at
http://pubs.usgs.gov/of/2004/1451/sltt/appendixA/.

\[This report was formerly available at the North American Geologic Map
Data Model Steering Committee website as
http://nadm-geo.org/sltt/products/sltt_summary_12_18_04.doc.\]

TABLE OF CONTENTS

[1 EXECUTIVE SUMMARY 4](#executive-summary)

[2 INTRODUCTION 6](#introduction)

[2.1 Background 6](#background)

[2.2 What is science language? 8](#what-is-science-language)

[2.3 Rationale 9](#rationale)

[2.4 Purpose 10](#purpose)

[2.5 Intended use 10](#intended-use)

[2.6 Related science-language efforts
10](#related-science-language-efforts)

[2.6.1 British Geological Survey 10](#british-geological-survey)

[2.6.2 International Union of Geological Sciences (IUGS)
11](#international-union-of-geological-sciences-iugs)

[2.6.3 Science language for glacial sedimentary materials
11](#science-language-for-glacial-sedimentary-materials)

[2.6.4 Geological Survey of Canada science language
11](#geological-survey-of-canada-science-language)

[2.6.5 Federal Geographic Data Committee (FGDC) science language
12](#federal-geographic-data-committee-fgdc-science-language)

[2.7 Who prepared this report? 12](#who-prepared-this-report)

[3 SLTT ACTIVITIES 13](#sltt-activities)

[3.1 Mandate and housekeeping 13](#mandate-and-housekeeping)

[3.2 Issues 13](#issues)

[3.3 20-queries exercise 14](#queries-exercise)

[3.4 Separation into subgroups 15](#separation-into-subgroups)

[3.5 Subgroup activities 15](#subgroup-activities)

[3.5.1 Iterative science-language development
15](#iterative-science-language-development)

[3.5.2 Internal SLTT review 15](#internal-sltt-review)

[3.5.3 NADMSC review 15](#nadmsc-review)

[3.5.4 Community-wide distribution 16](#community-wide-distribution)

[4 PHILOSOPHICAL AND OPERATIONAL ISSUES
17](#philosophical-and-operational-issues)

[4.1 Philosophical approach 17](#philosophical-approach)

[4.2 Legacy data *versus* future data
18](#legacy-data-versus-future-data)

[4.3 Definition of concepts 19](#definition-of-concepts)

[4.4 Guidelines followed by SLTT 21](#guidelines-followed-by-sltt)

[4.4.1 Science language compatible with geologic-mapping strategies
21](#science-language-compatible-with-geologic-mapping-strategies)

[4.4.2 Descriptive classification basis
22](#descriptive-classification-basis)

[4.4.3 Hierarchical structure 22](#hierarchical-structure)

[4.4.4 "Names" *versus* "modifiers" 23](#names-versus-modifiers)

[4.4.5 Clarity and ease of use 23](#clarity-and-ease-of-use)

[4.4.6 Robust yet flexible 23](#robust-yet-flexible)

[4.4.7 Compliance with North American traditions
24](#compliance-with-north-american-traditions)

[4.5 Does genesis play a role in earth-material classification?
24](#does-genesis-play-a-role-in-earth-material-classification)

[4.6 A final philosophical caveat 25](#a-final-philosophical-caveat)

[5 WHAT HAS SLTT ACCOMPLISHED? 26](#what-has-sltt-accomplished)

[5.1 Working documents *versus* a "standard"
26](#working-documents-versus-a-standard)

[5.1.1 Composite-genesis SLTT 27](#composite-genesis-sltt)

[5.1.2 Plutonic SLTT 27](#plutonic-sltt)

[5.1.3 Sedimentary SLTT 27](#sedimentary-sltt)

[5.1.4 Volcanic SLTT 28](#volcanic-sltt)

[5.2 Have we learned anything from the SLTT process?
28](#have-we-learned-anything-from-the-sltt-process)

[6 SUMMARY OF SCIENCE-LANGUAGE CLASSIFICATIONS
30](#summary-of-science-language-classifications)

[6.1 Igneous earth material 30](#igneous-earth-material)

[6.1.1 Plutonic earth material 30](#plutonic-earth-material)

[6.1.2 Volcanic earth material 31](#volcanic-earth-material)

[6.2 Composite-genesis rocks and rock particles
32](#composite-genesis-rocks-and-rock-particles)

[6.2.1 Metamorphic rock (traditional sense)
34](#metamorphic-rock-traditional-sense)

[6.2.2 Cataclastic rock 36](#cataclastic-rock)

[6.2.3 Impact-metamorphic rock 36](#impact-metamorphic-rock)

[6.3 Sedimentary earth material 37](#sedimentary-earth-material)

[7 REFERENCES CITED 42](#references-cited)

[8 Appendix 1 (SLTT CHARTER) 45](#appendix-1-sltt-charter)

[9 Appendix 2 48](#appendix-2)

[10 Appendix 3 51](#appendix-3)

[11 Appendix 4 53](#appendix-4)

[12 Appendix 5 57](#appendix-5)

[13 Appendix 6 59](#appendix-6)

# EXECUTIVE SUMMARY

A single uniform language to classify and describe earth materials and
their genesis is needed because producers and consumers of geoscience
information use names, terms, and icons to communicate information about
geologic objects and concepts. To the extent possible in a world where
words are used diversely and inconsistently, standardized terminology is
useful to facilitate information exchange.

The Science Language Technical Team (SLTT) of the North American Data
Model Steering Committee is a multi-constituency group of geologic-map
producers and geologic-map users that---during the period April 2000 to
November, 2004---developed a prototype science-language for the naming
and describing of earth materials in digital geologic-map databases
produced by public-sector entities in North America. The classification
adopts the following high-level architecture for earth-material name:

> Earth Material
>
> Igneous earth material
>
> Volcanic rock
>
> lithologic class based on composition
>
> lithologic class based on texture
>
> lithologic class based on emplacement characteristics
>
> Hypabyssal rock (BGS classification, Gillespie and Styles, 1999)
>
> Plutonic rock (BGS classification, Gillespie and Styles, 1999)
>
> Sedimentary earth material (unconsolidated, consolidated)
>
> Sedimentary material, unclassified
>
> Terrigenous-clastic sedimentary material
>
> Carbonate sedimentary material
>
> Organic-rich sedimentary material
>
> Non-clastic siliceous sedimentary material
>
> Noncarbonate-salt sedimentary material
>
> Phosphate-rich sedimentary material
>
> Iron-rich sedimentary material
>
> Composite-genesis earth material
>
> Cataclastic rock
>
> Impact-metamorphic material
>
> Metamorphic rock (traditional sense) (including hydrothermally-altered
> rock)
>
> granoblastic rock
>
> foliated metamorphic rock

These high-level categories fundamentally are genetic: they reflect how
earth material was formed (genetic process, crustal depth, etc.). This
raises the irony that, while deeper levels of the earth-material
classification hierarchy are based on what the mapping geologist can see
in the outcrop (empirical factors such as composition, structure, and
texture), upper-level categories are based on interpretations about how
the material was formed. Once this choice is made, an earth material is
classified in more detail based on textural or compositional
criteria---criteria that actually can be satisfied on the basis of
empirical observation.

The use of standardized science language in digital geologic-map
databases is a new frontier that is likely to evolve with time and
experience. With this in mind, we are developing classifications of
earth materials that we believe reflect not only how mapping geologists
view them but also how such materials might be queried and analyzed in
geologic-map databases. No single classification of earth materials will
please all workers. However, the schemes we propose hopefully will be
clearly understandable, internally consistent, and usable by both
data-producer and data-user.

# INTRODUCTION

## Background

With the increasingly widespread production and use of digital
geologic-map databases it has become clear that, to more effectively
serve their constituencies, geoscience agencies need to develop several
vital pieces of digital infrastructure:

(1) A standard conceptual model for storing digital data, and for
    manipulating these data in a relational and (or) object-oriented
    database environment;

(2) Standardized science language that allows geologic materials and
    geologic structures to be described, classified, and interpreted;

(3) Software tools for entering data into the standardized model at the
    front end (data-producer) and for extracting the data at the back
    end (data-user);

(4) Methodologies and techniques for exchanging data sets having
    different structures and formats.

To attain these objectives, public-sector geologic-mapping entities in
the United States and Canada formed a partnership called the North
American Data Model Steering Committee (NADMSC,
[http://nadm-geo.org](http://nadm-geo.org/)). This informal group is
sponsored by cooperative agreements between the U.S. Geological Survey
(USGS) and the Association of American State Geologists (AASG), and
between USGS and the Geological Survey of Canada (GSC). Through the
former, NADMSC is linked to the database and standards development
activities of the National Geologic Map Database
(<http://ngmdb.usgs.gov/>); through the latter, NADMSC is linked to
database-development activities ongoing in Canada under the auspices of
the Canadian Geoscience Knowledge Network.

This document and those that accompany it deal with task (2)
above---standardized science language that allows geologic materials and
geologic structures to be described, classified, and interpreted. To
execute this task, NADMSC chartered a Science Language Technical Team
(SLTT, <http://nadm-geo.org/sltt>) that first convened in early 2000.
SLTT members were identified in the following ways:

(1) Most participants from the U.S. Geological Survey were identified by
    Regional Geologic Executives from the USGS Western, Central, and
    Eastern Regions. This group includes representatives of the
    geologic-map editorial standards units of the regional publications
    groups. Additionally, some USGS scientists were appointed by
    Coordinators of USGS line-item science programs;

(2) Scientists from the Geological Survey of Canada were identified by
    Canadian members of the NADMSC;

(3) Scientists from State geological surveys were identified by the
    Digital Geologic-Mapping Committee of the Association of American
    State Geologists (AASG);

(4) Scientists from the U.S. Forest Service, National Park Service, U.S.
    Bureau of Land Management, and Natural Resources Conservation
    Service were selected by the committee chair;

(5) Scientists from academic institutions were selected by SLTT
    subcommittee co-chairs.

The assembled group (Table 2.1.1) represents a cross section of
public-sector geologic-map producers and map users in the United States
and Canada.

+---------------+------------------------------+-----------------------+
| **NADMSC      |                              |                       |
| Science       |                              |                       |
| Language      |                              |                       |
| Technical     |                              |                       |
| Team          |                              |                       |
| (Jonathan C.  |                              |                       |
| Matti,        |                              |                       |
| Chair)**      |                              |                       |
|               |                              |                       |
| **Committee   |                              |                       |
| Members**     |                              |                       |
+---------------+------------------------------+-----------------------+
| **            | **Affiliation**              | **SLTT Role**         |
| Participant** |                              |                       |
+---------------+------------------------------+-----------------------+
| Lee Allison   | Kansas Geological Survey     | General scientific    |
|               |                              | review                |
+---------------+------------------------------+-----------------------+
| Brian         | Ontario Geological Survey    | General scientific    |
| Berdusco      |                              | review                |
+---------------+------------------------------+-----------------------+
| Richard C.    | Illinois State Geological    | Sedimentary subgroup  |
| Berg          | Survey                       |                       |
+---------------+------------------------------+-----------------------+
| Thomas Berg   | Ohio Geological Survey       | General scientific    |
|               |                              | review                |
+---------------+------------------------------+-----------------------+
| Sam Boggs,    | University of Oregon         | Sedimentary subgroup  |
| Jr.           |                              |                       |
+---------------+------------------------------+-----------------------+
| Eric Boisvert | Geological Survey of Canada  | Sedimentary subgroup  |
+---------------+------------------------------+-----------------------+
| Andrée Bolduc | Geological Survey of Canada  | Sedimentary subgroup  |
+---------------+------------------------------+-----------------------+
| Mark W.       | U.S. Geological Survey       | Sedimentary subgroup  |
| Bultman       |                              |                       |
+---------------+------------------------------+-----------------------+
| William F.    | U.S. Geological Survey       | Metamorphic subgroup  |
| Cannon        |                              |                       |
+---------------+------------------------------+-----------------------+
| Robert L.     | U.S. Geological Survey       | Volcanic subgroup     |
| Christiansen  |                              | (co-chair)            |
+---------------+------------------------------+-----------------------+
| Jane Ciener   | U.S. Geological Survey       | Geologic-map          |
|               |                              | editorial standards   |
+---------------+------------------------------+-----------------------+
| Stephen P.    | Geological Survey of         | Metamorphic subgroup  |
| Colman-Sadd   | Newfoundland and Labrador    |                       |
+---------------+------------------------------+-----------------------+
| Peter         | Geological Survey of Canada  | General scientific    |
| Davenport     |                              | review                |
+---------------+------------------------------+-----------------------+
| Ron DiLabio   | Geological Survey of Canada  | Sedimentary subgroup  |
|               |                              | (co-chair)            |
+---------------+------------------------------+-----------------------+
| Lucy E.       | U.S. Geological Survey       | Sedimentary subgroup  |
| Edwards       |                              |                       |
+---------------+------------------------------+-----------------------+
| Robert        | New York State Geological    | General scientific    |
| Fakundiny     | Survey                       | review                |
+---------------+------------------------------+-----------------------+
| Kathleen      | North Carolina Geological    | Sedimentary subgroup  |
| Farrell       | Survey                       |                       |
+---------------+------------------------------+-----------------------+
| Claudia Faunt | U.S. Geological Survey       | Volcanic and          |
|               |                              | sedimentary subgroups |
+---------------+------------------------------+-----------------------+
| Mimi R.       | Missouri Department of       | Sedimentary subgroup  |
| Garstang      | Natural Resources            |                       |
+---------------+------------------------------+-----------------------+
| Joe Gregson   | National Park Service        | General scientific    |
|               |                              | review                |
+---------------+------------------------------+-----------------------+
| Ardith K.     | Illinois State Geological    | Sedimentary subgroup  |
| Hansel        | Survey                       |                       |
+---------------+------------------------------+-----------------------+
| Thomas D.     | Northern Arizona University  | Metamorphic subgroup  |
| Hoisch        |                              |                       |
+---------------+------------------------------+-----------------------+
| J. Wright     | U.S. Geological Survey       | Metamorphic subgroup  |
| Horton, Jr.   |                              | (co-chair)            |
+---------------+------------------------------+-----------------------+
| David W.      | U.S. Geological Survey       | Sedimentary subgroup  |
| Houseknecht   |                              |                       |
+---------------+------------------------------+-----------------------+
| Bruce R.      | U.S. Geological Survey       | Volcanic and          |
| Johnson       |                              | metamorphic subgroups |
+---------------+------------------------------+-----------------------+
| Robert Jordan | Delaware Geological Survey   | General scientific    |
|               |                              | review                |
+---------------+------------------------------+-----------------------+
| Ronald        | U.S. Geological Survey       | Plutonic subgroup     |
| Kistler       |                              | (co-chair)            |
+---------------+------------------------------+-----------------------+
| Alison        | Geological Survey of Canada  | Geologic-map          |
| Klingbyle     |                              | editorial standards   |
+---------------+------------------------------+-----------------------+
| Dennis R.     | Illinois Geological Survey   | Sedimentary subgroup  |
| Kolata        |                              |                       |
+---------------+------------------------------+-----------------------+
| Elizabeth D.  | U.S. Geological Survey       | Geologic-map          |
| Koozmin       |                              | editorial standards   |
+---------------+------------------------------+-----------------------+
| Hannan        | Natural Resources            | Sedimentary subgroup  |
| LaGarry       | Conservation Service         |                       |
+---------------+------------------------------+-----------------------+
| Diane E. Lane | U.S. Geological Survey       | Geologic-map          |
|               |                              | editorial standards   |
+---------------+------------------------------+-----------------------+
| Victoria E.   | U.S. Geological Survey       | Plutonic and          |
| Langenheim    |                              | Sedimentary subgroups |
+---------------+------------------------------+-----------------------+
| Reed Lewis    | Idaho Geological Survey      | Plutonic and Volcanic |
|               |                              | subgroup              |
+---------------+------------------------------+-----------------------+
| Stephen D.    | U.S. Geological Survey       | Volcanic subgroup     |
| Ludington     |                              |                       |
+---------------+------------------------------+-----------------------+
| Jonathan C.   | U.S. Geological Survey       | Sedimentary subgroup  |
| Matti         |                              |                       |
+---------------+------------------------------+-----------------------+
| James         | Ohio Geological Survey       | Sedimentary subgroup  |
| McDonald      |                              |                       |
+---------------+------------------------------+-----------------------+
| David M.      | U.S. Geological Survey       | Sedimentary subgroup  |
| Miller        |                              | (co-chair)            |
+---------------+------------------------------+-----------------------+
| Andy Moore    | Geological Survey of Canada  | Sedimentary subgroup  |
+---------------+------------------------------+-----------------------+
| Douglas M.    | U.S. Geological Survey       | Plutonic subgroup     |
| Morton        |                              |                       |
+---------------+------------------------------+-----------------------+
| Patrick       | Missouri Department of       | General scientific    |
| Mulvany       | Natural Resources            | review                |
+---------------+------------------------------+-----------------------+
| Carolyn Olson | Natural Resources            | Sedimentary subgroup  |
|               | Conservation Service         | (co-chair)            |
+---------------+------------------------------+-----------------------+
| Anne Poole    | National Park Service        | Plutonic and          |
|               |                              | sedimentary subgroups |
+---------------+------------------------------+-----------------------+
| Stephen M.    | Arizona Geological Survey    | Metamorphic subgroup  |
| Richard       |                              | (co-chair)            |
+---------------+------------------------------+-----------------------+
| Andrew H.     | U.S. Forest Service          | Sedimentary subgroup  |
| Rorick        |                              |                       |
+---------------+------------------------------+-----------------------+
| William       | Illinois State Geological    | General scientific    |
| Shilts        | Survey                       | review                |
+---------------+------------------------------+-----------------------+
| David R.      | U.S. Geological Survey       | Sedimentary subgroup  |
| Soller        |                              | (co-chair)            |
+---------------+------------------------------+-----------------------+
| Roy           | U.S. Geological Survey       | Sedimentary subgroup  |
| Sonenshein    |                              |                       |
+---------------+------------------------------+-----------------------+
| William       | U.S. Geological Survey       | Volcanic and          |
| Steinkampf    |                              | sedimentary subgroups |
+---------------+------------------------------+-----------------------+
| Douglas       | U.S. Geological Survey       | Plutonic subgroup     |
| Stoeser       |                              |                       |
+---------------+------------------------------+-----------------------+
| Lambertus C.  | Geological Survey of Canada  | General scientific    |
| Struik        |                              | review                |
+---------------+------------------------------+-----------------------+
| John F.       | U.S. Geological Survey       | General scientific    |
| Sutter        |                              | review                |
+---------------+------------------------------+-----------------------+
| Harvey        | Minnesota State Geological   | Sedimentary subgroup  |
| Thorsteinson  | Survey                       |                       |
+---------------+------------------------------+-----------------------+
| Robert J.     | Virginia Polytechnic         | Metamorphic subgroup  |
| Tracy         | Institute and State          |                       |
|               | University                   |                       |
+---------------+------------------------------+-----------------------+
| David Wagner  | California Geological Survey | Volcanic subgroup     |
+---------------+------------------------------+-----------------------+
| Richard Waitt | U.S. Geological Survey       | Sedimentary subgroup  |
+---------------+------------------------------+-----------------------+
| Peter D.      | U.S. Geological Survey       | Sedimentary subgroup  |
| Warwick       |                              |                       |
+---------------+------------------------------+-----------------------+
| Richard       | U.S. Bureau of Land          | General scientific    |
| Watson        | Management                   | review                |
+---------------+------------------------------+-----------------------+
| Gerald A      | Kentucky Geological Survey   | Sedimentary subgroup  |
| Weisenfluh    |                              | (co-chair)            |
+---------------+------------------------------+-----------------------+
| Carl          | U.S. Geological Survey       | Sedimentary subgroup  |
| Wentworth     |                              |                       |
+---------------+------------------------------+-----------------------+
| Michael L.    | University of Massachusetts  | Metamorphic subgroup  |
| Williams      |                              |                       |
+---------------+------------------------------+-----------------------+
| Ric Wilson    | U.S. Geological Survey       | Volcanic and plutonic |
|               |                              | subgroups             |
+---------------+------------------------------+-----------------------+
| Robert P.     | University of Indiana        | Metamorphic subgroup  |
| Wintsch       |                              |                       |
+---------------+------------------------------+-----------------------+
| Michael L.    | U.S. Geological Survey       | Plutonic and          |
| Zientek       |                              | metamorphic subgroups |
+---------------+------------------------------+-----------------------+

Table 2.1.1. NADMSC Science Language Technical Team committee members
(Jonathan C. Matti, Chair)

## What is science language?

Science language is the *vocabulary* of digital geologic-map databases:

*Vocabulary*---"n. **1.** the stock of words used by or known to a
particular people or group of persons\....**2.** a list or collection of
the words or phrases of a language, technical field, etc., usually
arranged in alphabetical order and defined. **3.** the words of a
language. **4.** any collection of signs or symbols constituting a means
or system of nonverbal communication: *vocabulary of a computer*\...."
(Webster\'s Encyclopedic Unabridged Dictionary of the English Language,
2001, p. 2129).

As with other endeavors, geologic maps and their accompanying databases
have a rich vocabulary of words, terms, and icons. These terms range
from the erudite (e.g. monzodiorite, arenite, granitic gneiss,
granoblastic) to the commonplace (landslide, sand, mudflow, fracture).
This language is the way geologists communicate technical information
about earth materials, and is the starting point for spatial analysis
that integrates geologic-map information with other kinds of geospatial
data sets.

## Rationale

Standardized science language is needed to increase the usability and
comparability of information contained in geologic-map databases.

A map user might conclude that terms occurring in map-unit explanations
and in database fields have identical meanings from map to map and from
region to region. This certainly is true for some specialized terms, and
is even more true for more-generalized terms. However, for some terms
used in geologic maps, subtle to significant differences in geologic
meaning can occur from map to map. This happens for various reasons:

(1) The field description and interpretation of earth materials and
    geologic structures is as much an art as a science, and is
    vulnerable to the experience, training, intuition, skill, and
    persistence of the geologic-map maker. Moreover, each field area
    presents unique challenges to the geologic-mapping process (outcrop
    quality, climatic setting, accessibility, etc.). These realities
    open the door to differences in science language usage from map to
    map;

(2) The meaning of some terms changes subtly to significantly from
    generation to generation as academic traditions change, and as new
    analytical techniques and geologic perspective influence and modify
    research results and teaching curriculums. New and different science
    language commonly emerges from these activities;

(3) Some geologic terms once in vogue may completely disappear from the
    geologic lexicon as they are replaced with terms that are more
    accurate or precise or that better reflect current thinking;

(4) Some geologic terms take on meanings and applications specific to a
    particular geologic terrain or region; beyond that region, these
    terms may have a slightly different meaning, or may not even be
    used;

(5) In a climate of open and competitive academic research, scientists
    constantly are experimenting with new, more creative and more
    effective terminology to communicate information about earth
    materials that have complex combinations of composition, structure,
    fabric, and genesis.

For these reasons, the vocabulary (science language) of both historic
and current geologic maps can vary---in some instances enough to create
uncertainty on the part of the map user as to whether earth materials
and geologic structures in one map are similar to or different from
those in another. To minimize this problem, standardized science
language that classifies and describes earth materials and their genesis
is helpful.

In short, in a diverse world of words, standardized terminology is
useful to facilitate information exchange.

## Purpose

The SLTT purpose is to develop a science-language standard[^1] for the
description, classification, and interpretation of earth materials in
geologic-map databases. The language should provide a logical,
consistent, hierarchical framework for naming and classifying earth
materials, and for describing their physical characteristics and
genesis---based on the way geologic maps are made by the field geologist
or assembled by a science compiler (Section 3.6.2).

It is our hope that, in the SLTT documents, we have broken down common
terms for earth materials into their fundamental science concepts. This
is based on our belief that it is not so much what an object or concept
is called, but what the name means in terms of the science concepts it
represents. If we can reach consensus on the concepts then, perhaps with
a single mouse click, the defining attributes of each object or concept
can be parsed into a geologic-map database for subsequent query and
analysis---no matter what the object is called. The SLTT documents
provide specific defined names for earth-material objects and concepts,
with the hope that they will be familiar and palatable to the average
geologic-map maker and map user. However, we understand that each map
producer and map user will have their own favorite names, and that
humans are reluctant to abandon terms and meanings with which they are
comfortable. With that recognition, we believe SLTT will have served its
purpose if it provides a yardstick against which terms can be compared
and translated---the true meaning of a "standard".

## Intended use

Science language developed by the SLTT is intended for use by persons
and agencies that submit digital geologic-map data into public-domain
databases managed by various State/Provincial and Federal agencies. We
are not setting standards for use by academia or by the private sector,
unless these entities contribute geologic-map products to public
databases.

Intended users include:

-   geologists who collect original data in the field while making a
    geologic map;

-   geologists who compile geologic-map data from legacy sources and
    must interpret and translate these data for representation in the
    compilation;

-   information-users who query public-domain geologic-map databases for
    information appropriate to their interests and applications.

## Related science-language efforts

SLTT deliberations benefitted from previous and ongoing science-language
efforts being conducted by other entities.

### British Geological Survey

In a precedent-setting effort, in 1999 the British Geological Survey
(BGS) issued four reports that presented science language for earth
materials from a geologic-mapping point of view:

-   science language for igneous materials (Gillespie and Styles, 1999)

-   science language for metamorphic materials (Robertson, 1999)

-   science language for sedimentary materials (Hallsworth and Knox,
    1999)

-   science language for surficial and man-made materials (McMillan and
    Powell, 1999).

The SLTT adopted major elements of the BGS approach, but found that in
order to accommodate North American geologic-mapping traditions and
approaches we had to develop slightly modified terminology and taxonomic
hierarchies.

### International Union of Geological Sciences (IUGS)

SLTT activities benefitted from a series of IUGS sub-commissions
chartered to develop uniform classifications of earth materials:

-   [Igneous materials]{.underline}: A long-standing IUGS Subcommission
    on the classification of plutonic and volcanic igneous rocks
    (<http://www.minpet.uni-freiburg.de/IUGS-CSP.html>) has led to a
    widely accepted standard (IUGS, 1973; MacDonald, 1974; Streckeisen,
    1974, 1976, 1978, 1979; Schmid, 1981; Heiken and Wohletz, 1985;
    Foley and others, 1987; Le Bas and others, 1986; Le Maitre and
    others, 1989; Le Bas and Streckeisen, 1991; Le Maitre and others,
    2002).

-   [Metamorphic materials]{.underline}: An IUGS Subcommission on the
    classification of metamorphic rocks
    (<http://www.bgs.ac.uk/SCMR/scmr_products.html>) is underway, and is
    stimulating wide-ranging discussion of terminology for the naming,
    description, and genesis of metamorphic rocks.

-   [Sedimentary materials]{.underline}: An IUGS Subcommission on the
    classification of sedimentary materials
    (<http://www.iugs.org/iugs/science/sci-cgsg.htm>) is in the initial
    phases of its activities.

### Science language for glacial sedimentary materials

The International Union for Quaternary Research \[INQUA\] in the 1970's
sponsored a Commission on Genesis and Lithology of Glacial Quaternary
Deposits (Commission C-2). The results of Commission C-2 were published
in Goldthwait and Matsch (1988; see Commission summaries in Goldthwait
and others, 1988, p. vii-ix, and Dreimanis, 1988, p. 19-25). The SLTT
used this document to develop science language for sedimentary materials
of glacial origin.

### Geological Survey of Canada science language

Concurrent with SLTT activities, the Geological Survey of Canada (GSC)
is developing science language for use by GSC projects producing digital
geologic-map databases. Through a series of projects, GSC has
investigated approaches to developing geological map databases,
including prototype data models and user interfaces. Bedrock and
surficial geological maps have to date been addressed separately. As
part of data modeling, based on variants of NADM, several approaches
have been tested to enable interoperability among maps that use varied,
usually undefined and sometimes inconsistent science language,
particularly for the earth-material constituents of map units.

Two main approaches have been tried, both relying on map context and
geological experience as guides to the authors' meaning. For surficial
geological maps, the uncontrolled and variable terminology is
reinterpreted within a controlled set of defined terms (a translation,
in effect). For bedrock maps, earth material names are
"reverse-engineered" into the properties (genetic process, composition,
texture, etc.) implied by each name (single word or phrase), using sets
of keywords for these properties (Davenport and others, 2002). In both
approaches, a hierarchical organization of terms is applied wherever
possible to allow for categorization at variable levels of precision in
accordance with the information available, and to enable efficient
querying of the databases.

For bedrock maps, Struik and others (2002) followed a different
approach, recognizing that earth material names are multi-dimensional
and can be organized in a variety of hierarchies depending on the choice
of criteria (genetic process, composition, texture, etc.). The earth
material names that Struik and others (2002) considered were
uncontrolled terms gleaned from several published geological maps, but
were neither exhaustive nor representative of the entire collection of
published maps for Canada. This approach has been extended to collect
earth material names in a master list as additional maps are brought
into the database, and associate controlled keywords for earth material
properties to each unique term (single word or phrase) through a data
model that supports multiple ontologies. This enables map units to be
searched or grouped by one or several of these keywords. User interfaces
have been written to streamline the analysis of map unit descriptions,
extraction of earth material types, and the assignment of keywords.

### Federal Geographic Data Committee (FGDC) science language

Within the United States, an important science-language activity is
occurring under auspices of the Federal Geographic Data Committee (FGDC)
Geologic Data Subcommittee (<http://ncgmp.usgs.gov/fgdc_gds/>). The FGDC
has developed a draft cartographic standard for polygon, line, and point
symbols that depict geologic features on geologic maps and digital
displays. Although primarily concerned with cartographic technical
specifications, the FGDC cartographic standard contains science-language
concepts that should be integrated with the science-language in these
SLTT documents.

## Who prepared this report?

The SLTT chair (Matti) prepared this summary in coordination with the
SLTT subgroup leaders (Table 2.7.1), each of whom contributed to the
narratives in Section 5.

  ----------------- ----------------------------- -----------------------
  Robert L.         U.S. Geological Survey        Volcanic subgroup
  Christiansen                                    

  Andrée Bolduc     Geological Survey of Canada   Sedimentary subgroup

  Ron DiLabio       Geological Survey of Canada   Sedimentary subgroup

  J. Wright Horton, U.S. Geological Survey        Metamorphic subgroup
  Jr.                                             

  Stephen D.        U.S. Geological Survey        Volcanic subgroup
  Ludington                                       

  Jonathan C. Matti U.S. Geological Survey        Sedimentary subgroup

  David M. Miller   U.S. Geological Survey        Sedimentary subgroup

  Carolyn G. Olson  Natural Resources             Sedimentary subgroup
                    Conservation Service          

  Stephen M.        Arizona Geological Survey     Metamorphic subgroup
  Richard                                         

  David R. Soller   U.S. Geological Survey        Sedimentary subgroup

  Gerald A          Kentucky Geological Survey    Sedimentary subgroup
  Weisenfluh                                      
  ----------------- ----------------------------- -----------------------

Table 2.7.1. SLTT Subgroup leaders who contributed to this report.

# SLTT ACTIVITIES

## Mandate and housekeeping

The SLTT was created in 1999 as a technical working group of the North
American Geologic-map Data Model Steering Committee (NADMSC), and is
guided by a charter that identifies our goals and objectives (Appendix
1).

Early in its deliberations, SLTT had to figure out what exactly we were
going to do, what the scope of our assignment was, how we would
reconcile various geological traditions and perspectives represented by
the SLTT group and their constituents, and how we would develop a
consensus science language. To facilitate this discussion, the SLTT
chair (Matti) periodically issued memoranda that stated guidelines,
summarized deliberations, and ameliorated differences of approach. Some
of these memos are archived in Appendices 2-6 of this report.

SLTT conducted its activities without dedicated salary and without a
dedicated travel budget. As a result, face-to-face meetings generally
were not possible, and SLTT members had to boot-leg time from their
agency science projects---usually at the expense of project
deliverables. The majority of SLTT interactions have been in the form of
email discussions and conference calls. Both internal and external
evaluation of science-language concepts was facilitated by a
web-conference site (see <http://nadm-geo.org/sltt/terms/index.html>)
that stimulated discussion of philosophical and operational issues.

## Issues

Early in the SLTT process, tensions developed between two very different
science-language goals and strategies:

(1) Classifying the terminology of geologic maps so that each term
    commonly used in map legends and map-marginal explanations can be
    found in science-language classification schema.

> This objective focuses on *legacy* geologic-map information and on
> science language that enables the compilation of such information,
> without having to determine how the author of the map used the
> geologic terminology. By this rationale, science-language
> deliberations should determine how to organize *existing*
> earth-material names, based on the premise that the names are the
> principle basis for conveying science content.

(2) Creating science-language schema that allow the map author or map
    compiler to represent what actually is known about the earth
    materials portrayed on a geologic map.

> This objective focuses on the geologic-mapping process itself---that
> is, on the way geologists use terms to express what they see in
> outcrops and in hand specimens, how they make mapping decisions in the
> field, how they organize and present their map data to express
> confidence in their observations and interpretations, and how the
> scientific content of current and future geologic-map databases can be
> improved and clarified. By this rationale, science-language
> deliberations should provide the map maker or map compiler with (1)
> very specific names that can be used where field data warrant or where
> legacy map terminology is clear, or (2) higher-level general names
> that can be used where field data are ambiguous or where the use of
> legacy map terminology is not clear. This rationale is driven by the
> premise that the scientific content, not just the names, is what
> geologic-map users are looking for.

These two objectives are equally legitimate. However, they reflect
different philosophies and lead to different science-language
strategies. Tensions between them were not resolved during the course of
SLTT deliberations and, as a consequence, significant differences in
scope, content, purpose, and philosophy exist among the various SLTT
reports. This is not a deal-breaker, but it does illustrate the
complexity and challenges of developing a standard science-language.
Moreover, it should be a valuable lesson for agencies that conduct
geologic mapping and that intend to develop local, regional, and
national geologic-map databases that have uniform science content.

The volcanic subgroup concluded that their principal objective was to
classify volcanic earth-material names into schema (picklists) that
accommodate the diversity and inconsistency of usage in legacy geologic
maps---where it commonly is not possible to know the exact meaning or
intent of the original map maker. In general, the volcanic subgroup
decided not to address these issues by exploring ways of reconfiguring
or re-organizing the science language of volcanic earth materials, but
instead focused on how to preserve the meaning of original map usage in
the context of traditional classification approaches.

The composite-genesis and sedimentary subgroups concluded that their
principal objective was to examine the science concepts embedded in
geologic-map terminology, and to develop classification schema organized
around that conceptual content. This philosophical approach forced a
re-examination of how traditional map terms are used, and in some
instances led these subgroups either not to adopt as controlled terms
some familiar earth-material names, or to position these names in
classification hierarchies in a different place than where some workers
might expect to find them. For future geologic-mapping activities and
their resulting databases, this probably will not create any long-term
problems---provided future geologic mappers understand and agree with
SLTT approaches. For legacy geologic-map information, the approach
adopted by the composite-genesis and sedimentary groups might require
some decision making on the part of the information compiler: (1) for a
legacy term whose original meaning was not clear, the map compiler might
have to use a higher-level, more generalized SLTT term instead, or (2)
where a legacy term is understood to have a different meaning than the
SLTT rendering of the same term, the map compiler may have to use a
different SLTT term for the same concept (but see [footnote
2](#footnote_2)).

## 20-queries exercise

SLTT's first order of business tasked each committee member to submit
twenty queries to a hypothetical geologic-map database. This exercise
had two purposes;

(A) it served as a proxy for a requirements analysis that might be
    conducted among users of digital geologic-map data, to determine how
    such products are used and how the geologic data might be structured
    and organized from a content and language point of view;

(B) it was a means of getting each SLTT member to think about the
    science concepts that might be embraced by geologic-map databases,
    along with the issues and problems associated with naming, relating,
    and querying information about geologic materials and geologic
    structures.

Results of the 20-queries exercise (see
<http://nadm-geo.org/sltt/products/sltt_20_queries_master.pdf>) revealed
that database-users (at least those on the committee) were interested in
a broad spectrum of geologic concepts and database targets ranging from
(1) academic queries related to the lithology, genesis, geometry, and
age of geologic materials and structures to (2) pragmatic queries
targeting what information geologic-map units and geologic structures
contain about natural resources, fluid transmissivity (ground water and
hydrocarbons), geologic hazards (swelling ground, landslides,
earthquake-induced ground-shaking), and land-use planning (landfill
siting, ground-water recharge, commercial and residential development,
infrastructure siting). SLTT's task was to develop science language to
facilitate this broad range of potential database queries.

Results of the 20-queries exercise were passed along to the NADMSC Data
Model Design Team (DMDT) for analysis and (especially) to ensure that
science concepts emerging from the SLTT process were considered by DMDT
as it developed architecture for a standard geologic-map data model.

## Separation into subgroups

Early on, SLTT decided to split into subgroups organized around major
classes of earth material:

-   plutonic subgroup (R.L. Kistler and D.M. Morton, co-chairs)

-   volcanic subgroup (S. Ludington and R. Christiansen, co-chairs)

-   metamorphic subgroup (J.W. Horton and S.M. Richard, co-chairs)

-   sedimentary subgroup (J.C. Matti and G.A. Weisenfluh, co-chairs)

-   surficial-materials subgroup (R. DiLabio, D.M. Miller, C.G. Olson,
    D.R. Soller, and A.M. Bolduc, co-chairs).

Ultimately, SLTT recommended to NADMSC that the surficial and
sedimentary subgroups merge into a single group, based on three factors:

1.  unconsolidated surficial materials are sedimentary in origin;

2.  the lithology, physical properties, genesis, and geomorphology of
    sedimentary and surficial materials are identical;

3.  scientific perspectives and geologic-mapping experience in the two
    subgroups complemented each other and provided insights beneficial
    to both groups.

NADMSC approved this recommendation, and the combined sedimentary and
surficial subgroups have worked together to develop a single body of
science language for unconsolidated and consolidated sedimentary
materials.

The SLTT chair selected subgroup co-chairs based on the following
criteria: geologic-mapping experience, expertise in their science field,
and knowledge of their agency's role in producing or using geologic-map
databases. Subgroup co-chairs reflect a range of American and Canadian
constituencies and Federal and State perspectives.

## Subgroup activities

### Iterative science-language development

Using the 20-queries exercise and building upon the four BGS
classification documents, the SLTT subgroups iteratively developed
science-language schemes that were exchanged by email among subgroup
members. This process continued from about September, 2000 through
November, 2004.

### Internal SLTT review

After each subgroup completed a consensus classification of earth
materials, subgroup documents were submitted for SLTT-wide peer review.
This review was intended to ensure uniformity of philosophical and
operational approach throughout the SLTT science-language process.

### NADMSC review

Following internal SLTT-wide peer review, SLTT science language
documents were forwarded to the NADMSC for evaluation and review for
consistency, for geopolitical sensitivity, and for compatibility with
the data-model architecture being developed by the DMDT.

### Community-wide distribution

Following NADMSC approval, the SLTT documents are being released on the
NADM website for presentation to the North American geologic-mapping
community.

# PHILOSOPHICAL AND OPERATIONAL ISSUES

## Philosophical approach

The question of "What's in a name?" has plagued taxonomic
classifications in all scientific arenas.

Historically, people have coined names for objects or concepts in order
to convey information about them. The names are shorthand expressions
(representations or proxies) for information packets that commonly are
quite complex. This is acceptable practice because the human brain is
able to extract from a single name the many attributes and components
that the name represents. Now, we are asking computer databases to do
this job.

To come to grips with our task, SLTT members wrestled with the
difference between "name" and "modifier" (see definitions in Section
4.3), and the implications these two concepts have for naming earth
materials and for organizing the names into classification hierarchies.
We considered the following two end-member choices:

-   Should each "name" express *multiple attributes and concepts*, as
    names historically have? By this approach, names for earth materials
    would synthesize as much information as possible about lithologic
    and genetic attributes in order to make communication efficient
    (i.e., fewer words, with each word being compound and reflecting
    multiple attributes);

-   Should each "name" express *few attributes and concepts*, in order
    to reflect only those attributes essential for the identification
    and naming of an object or concept? This approach might make
    communication more cumbersome in terms of word load (i.e., more
    words, with each word having a narrow meaning), but communication
    would be extremely accurate and precise.

The SLTT subgroups did not reach consensus on which of these approaches
to follow.

Some committee members argued that our mandated task (Appendix 1) was to
organize existing terminology into classification schema, without
addressing how this terminology might be used more effectively in
geologic-map databases. Other members argued that the SLTT
classification schema should preserve traditional usage as much as
possible, but organize classification schema around the fundamental
science concepts or attributes represented by an earth-material name.
This philosophical approach would require a re-examination of how
traditional map terms are used, and might lead to schema that (1) do not
adopt as controlled terms some familiar earth-material names, or (2)
that place certain names in hierarchical positions that are not familiar
to or comfortable with all geologists.

Each SLTT subgroup handled the "what's in a name" issue in its own way,
but the resulting classification schema have some common themes:

-   We all agreed that high-level terms, by their very nature, must be
    compound and complex because, at their high classification level,
    they need to embrace all the attributes and concepts represented by
    deeper-level terms in the classification;

-   for progressively deeper-level geologic terms we tried to minimize
    their compound nature, but allowed each subgroup to develop
    classifications schemes that reflected their own vision for how
    names best describe their earth material;

-   each hierarchical level in the proposed classifications is designed
    to contain names or terms that represent geologic concepts that are
    as narrowly defined as possible.

## Legacy data *versus* future data

The North American geologic-map endowment has two components: (1)
"legacy data" archived in paper maps and digital files as the result of
many generations of geologic-mapping activities, and (2) new data that
will be collected through the efforts of future geologic-mapping
activities. Incorporation of these two kinds of data sets into digital
geologic-map databases involves different kinds of strategies, each
posing its own challenge to geologic-map science language.

North American legacy geologic maps are rich in geologic terminology.
Typically, such data are contained either in map-marginal descriptions
of map units or in pamphlets and reports that accompany the geologic
map. Unfortunately, legacy maps rarely cite the classification systems
used by the map maker to name and describe earth materials.
Consequently, it is left to the map user to interpret the meaning and
usage of such terminology. For high-level terms (e.g., sedimentary rock,
terrigenous-clastic sediment, plutonic rock, metamorphic rock, volcanic
rock) the meaning may be universally understood. However, for
deeper-level terms (e.g., shale, mud, basalt, quartz latite, quartz
monzonite, granodiorite, volcaniclastic, slate, lahar, greenstone,
gneiss, layered gneiss) the meaning may not be clear because many terms
have inconsistent usage depending on when and where the map maker
learned his or her craft. As a result, the map user commonly must
interpret the meaning of earth-material terms according to his or her
own experience.

This problem is compounded by two factors:

(1) some terms (e.g., sandstone, granite, shale, gneiss) have acquired
    usages that border on the generic or commonplace, and lack strict
    definitions or meanings;

(2) some terms (e.g., alluvium, greenschist, till, turbidite,
    metasediment, loess, debris flow, lahar) have been used as though
    they were lithologic names, when in fact they are genetic terms;
    this practice has blurred the distinction between lithologic
    description and genetic interpretation.

As a group, the SLTT committee had to wrestle with these issues, and
decide on whether our science-language approach (1) should attempt to
accommodate historical usage that is diverse, inconsistent, and in some
cases generic, or (2) should reflect the needs and requirements of
future geologic-map makers for science language that is stable and
consistent. Ideally, any such decision will reflect the policy of the
database developer, which usually means the management policy of the
geologic-mapping agency or entity. With respect to legacy information,
two contrasting data-management choices apply:

(1) modern databases should archive and organize legacy terminology
    verbatim, without attempting to translate such terms into modern
    science language;

(2) modern databases should interpret and translate legacy terms in the
    context of modern science-language structures, preserving archival
    terminology where it is clearly understood in terms of a modern
    standard but using more generalized terminology where the specific
    original meaning cannot be reconstructed[^2].

The SLTT group is not mandated to make such a policy decision on behalf
of its constituent agencies. However, we recognize that legacy geologic
maps include a wide variety of earth-material terms, many of which have
similar, if not identical, meanings. Our purpose was to review how such
terms have been used historically, and to judge how useful they are for
storage, manipulation, retrieval, and analysis in geologic-map
databases. In most instances, we found that traditional earth-material
nomenclature lends itself well to database applications. However, the
composite-genesis and sedimentary SLTT groups found that some
traditional terminology and classification schemes did not adapt
themselves easily to database requirements. In such instances, those
subgroups had to modify existing names slightly, abandon some terms, or
propose new names.

The SLTT result is a hierarchical classification of earth materials that
accommodates two objectives:

(1) it allows legacy map terminology to be brought into modern
    geologic-map databases, using archival terminology where appropriate
    or by using generalized terminology where the specific original
    meaning is not clearly determinable;

(2) it allows future geologic mappers to archive information about earth
    materials in a manner that is consistent, uniform, flexible, and
    forward-looking.

## Definition of concepts

The SLTT documents use concepts and terms that have common generic
meanings. However, in the case of science language for geologic-map
databases, these terms need to be delineated without ambiguity. The
following definitions guided our deliberations:

[]{#characterize .anchor}*Characterize*---"v.t. **1.** to mark or
distinguish as a characteristic; be a characteristic of\....**2.** to
[describe](#describe) the character or individual quality of\....**3.**
to attribute character to\...." (Webster\'s Encyclopedic Unabridged
Dictionary of the English Language, 2001, p. 347).

*Classify*---"v.t. **1.** to arrange or organize by classes; order
according to class. **2.** to assign a classification to (information, a
document, etc)" (Webster\'s Encyclopedic Unabridged Dictionary of the
English Language, 2001, p. 381). To classify is to assign an *instance*
to a group defined on the basis of a set of properties shared by members
of the group. To *classify* answers the question "what kind of X is
instance Y?", where X represents the domain of the classification.

[]{#controlled .anchor}*Controlled term*---A term or [name](#name) whose
meaning and scope is restrained or restricted so that the term can be
used or applied only according to the definition contained in a
standard.

[]{#define .anchor}*Define*---" v.t. **1.** to state or set forth the
meaning of\....**2.** to explain or identify the nature or essential
qualities of\....**3.** to fix or lay down definitely; specify
distinctly\....**4.** to determine or fix the boundaries or extent
of\....**5.** to make clear the outline or form of\...." (Webster\'s
Encyclopedic Unabridged Dictionary of the English Language, 2001, p.
523).

[]{#describe .anchor}*Describe*---"**1.** to tell or depict in written
or spoken words; give an account of: *he described the accident very
carefully*\...." (Webster\'s Encyclopedic Unabridged Dictionary of the
English Language, 2001, p. 538).

*Description*---"1. a statement, picture in words, or account that
describes: descriptive representation\...." (Webster\'s Encyclopedic
Unabridged Dictionary of the English Language, 2001, p. 538). A
description is a set of statements that [characterize](#characterize)
the nature of an object or thing such that it can be identified and
[named](#name).

*Earth material*---A naturally occurring substance formed in or on the
Earth by physical, chemical, or biogenic processes that produce solid
particles or crystals of mineral and (or) rock.

*Instance*---"n. **1.** a case or occurrence of anything\...."
(Webster\'s Encyclopedic Unabridged Dictionary of the English Language,
2001, p. 988).

*Geologic-map unit*---An intellectual construct that a geologist
delineates on a map as a way to communicate a geologic concept to the
map user. Each geologic-map unit corresponds to a three-dimensional
volume of earth material that consists of one or more discrete
lithotopes whose character and (or) frequency of occurrence makes each
map unit distinct and unique from other such units (ideally). The map
maker defines the scope, scale, boundaries, names, and reference
sections for geologic-map units according to rules developed and
adjudicated by the North American Commission on Stratigraphic
Nomenclature (NACSN, 1983). According to the NACSN, geologic-map units
can be lithostratigraphic units, lithodemic units, allostratigraphic
units, and pedostratigraphic units.

*Lithotope*---A body of sediment or rock that can be "a stratigraphic
unit, a part of a stratigraphic section, a particular kind of sediment
or rock, \[or\] a body of uniform sediments formed by the persistence of
the depositional environment" *Glossary of Geology* (Jackson, 1997, p.
373).

*Modifier*---A term or word that qualifies or amplifies a [controlled
term](#controlled) or [name](#name). By the rules that SLTTS_1.0
followed, the name of an object reflects the defining attributes by
which the object is recognized; by contrast, a modifier extends the name
by adding supplemental information, usually about a different concept
that is not used as a defining attribute. For example, if a sedimentary
earth material is [defined](#define) strictly by textural criteria
(e.g., grain-size ratios), then any words that add information about
composition or structure, etc., add value beyond the information
[necessary](#necessary) to recognize the material. . The distinction
between "modifier" and "name" is discussed further in Section 4.4.4.

[]{#name .anchor}*Name*---"n. **1.** a word or a combination of words by
which a person, place, or thing, a body or class, or any object of
thought is designated, called, or known\...." (Webster\'s Encyclopedic
Unabridged Dictionary of the English Language, 2001, p. 1276). By this
definition, a name is a shorthand proxy for the description that
[defines](#define) the nature of something. The naming process needs to
reflect the rules of the game: that is, names should correspond to the
essential attributes by which the object is defined. The distinction
between "name" and "modifier" is discussed further in Section 4.4.4.

[]{#necessary .anchor}*Necessary*---"**1.** being essential,
indispensable, or requisite\....**4.** *Logic*\....**c.** (of a
condition) such that it must exist if a given event is to occur or a
given thing is to exist\...." (Webster\'s Encyclopedic Unabridged
Dictionary of the English Language, 2001, p. 1284).

*Standard*---"*n*. **1**. Something considered by an authority or by
general consent as a basis of comparison. **3**. a rule or principle
that is used as a basis for judgment: *they tried to establish standards
for a new philosophical approach*. ---*adj*. **23.** serving as a basis
of weight, measure, value, comparison, or judgment. **24**. of
recognized excellence or established authority. **25.** usual, common,
or customary:\..." (Webster\'s Encyclopedic Unabridged Dictionary of the
English Language, 2001, p. 1857).

## Guidelines followed by SLTT

In developing science language for sedimentary materials, we adopted the
following rules:

### Science language compatible with geologic-mapping strategies

The goals and methods of geologic mapping require science-language
structures that are different from those of other endeavors. This is
because geologic maps are made using rules, procedures, and
interpolations whose objectives differ from those of other geoscience
activities.

The very nature of the geologic-mapping process requires that the scope,
scale, and consistency of geologic observation varies throughout the map
footprint. This is because the nature and quality of each observation
varies from place to place, depending on its purpose, the time available
to make it, and the quality of the geologic outcrop. Many observations
upon which the map is based are detailed and comprehensive; others are
generalized and cursory. The latter typically are not the fault of the
geologic-map maker, but rather are intrinsic to the geologic-mapping
process itself: every potential observation point within the map
footprint cannot be examined with the same level of definitive care and
quality, and the information content within a geologic-map unit must be
extrapolated between observation points---some of which may be quite far
apart.

Consider the type of observation a mapping geologist might make in
determining whether a particular outcrop should be included within a
particular map unit or excluded from it:

-   Binocular observation of a distant outcrop series to determine the
    ratio between 'sandstone' and 'conglomerate' ("Looks to me like
    'sandstone' dominates over 'conglomerate');

-   Casual observation of grain-size ratios in an outcrop in order to
    confirm that lithologic trends in a series of outcrops still apply
    ("Looks like the same old 'sandstone' beds. Don't need to examine
    these very carefully");

-   Detailed hand-lens determination of grain-size ratios in a series of
    sedimentary beds in order to characterize a given outcrop in detail
    ("These 'sandstone' beds look a little different from the previous
    ones; I better spend some time and compare them to those in the
    preceding outcrops, just to be sure they belong in the same map
    unit");

-   Follow-up petrographic analysis to determine details of texture,
    fabric, and grain mineralogy ("Even though I described these beds in
    the field as 'sandstone' based on hand-lens observation, I see on
    the basis of microscope observation that the mud-size fraction is
    greater than I originally believed. These beds more properly should
    be termed 'muddy sandstone', and they are more akin to the mudstones
    of Formation Y than they are to the sandstones of Formation X").

The preceding examples suggest that a hierarchical observational
approach characterizes the geologic-mapping process---ranging from
generalized observations that are cursory in scope to detailed
observations that are definitive in scope. Each observational style has
its own confidence level. Moreover, science-language terms for each
observational level have slightly different meanings depending on the
scale of observation. In each of the preceding examples, does the term
"sandstone" have the same meaning? Are different types of information
communicated through the use of "sandstone" in each circumstance?

We answer "no" to the first question and "yes" to the second, and we
conclude that the science language of earth materials must be structured
to be parallel with or consistent with the hierarchical nature of
observations made during the geologic-mapping process. This is a
different process than takes place in the controlled environment of a
petrology laboratory, where specific kinds of questions are pursued
systematically and answered using a specific kind of precise language.

This is not to say that the observational quality of geologic-map
information is inferior. However, developers and users of science
language for geologic maps need to be aware that (1) not all
observations have the same level of refinement and (2) information
projected (extrapolated) outward away from observation points without
benefit of intervening data---the essence of geologic-map making---is
vulnerable. These limitations compel the science language of
geologic-map data sets to be constructed in a way that is compatible
with geologic-mapping strategies.

### Descriptive classification basis

To produce a classification system for earth materials that allows
different observers to classify a given material in the same way, the
system must be based on physical properties recognizable by all
observers. The properties traditionally used for field classification of
earth materials include particle mineralogy and composition, particle
size, particle shape, fabric (the arrangement of particle in an
aggregate to form the material), and structures in the material
(bedding, layering, etc.). Although bodies of earth material may be
recognized based on other physical properties (e.g., magnetic
susceptibility, density), these generally are not used as field
criteria.

The approach to a lithologic classification developed in the SLTT
documents fundamentally is descriptive---that is, classification of an
earth material is based on observable features of the material, and its
assignment to a lithologic class implies that certain descriptive
criteria are met. These criteria must be defined in the database in
order to document the classification system. The descriptions that
define the lithologic classes also serve to provide default values for
rock properties that are assigned to a lithologic class, but not
described in greater detail. Thus, the name for a sedimentary material
(e.g., sandstone, calcareous dolostone, slightly gravelly sand) is a
proxy for a default description parsed into the database simply through
application of a name to the material (e.g., sandstone, monzogranite,
pelitic schist).

### Hierarchical structure

The science language should be progressive---that is, it should be based
on what the geologist can observe and describe sequentially during the
course of making a geologic map, first with the un-aided eye, then with
hand lens, and then with more detailed analysis (e.g., thin sections).
Each of these observation types yields a package of information that
differs in scope, content, and rigor from that in the others. If this is
true, then the SLTT process ideally should develop lithologic names that
are compatible with these various observation types.

The progressive nature of the observation process (from reconnaissance
to detailed) requires a hierarchical language structure---that is,
language that begins at a generalized level and develops into
progressively more specific categories that communicate more refined
information about an earth material. To the extent possible, this
hierarchical structure should follow the rules of parent-child
lineages---that is, each child can occur only once in the hierarchy, and
can have only one parent. If this rule is not followed, multiple
parentage will complicate the organization of geologic concepts and it
will be more difficult to retrieve information from the database.

Developing a logical hierarchical structure proved to be vexing. As with
Linnean zoological taxonomy, the purpose of organizing earth-material
names into parent-child lineages is to identify logical relationships
among individual rock types and groups of rock types; taxonomic names
presumably should reflect these relationships. In the case of digital
geologic-map databases, the premise is that lumping and splitting
real-world objects into inter-related categories will help in analyzing
the objects, and will facilitate searching the geologic-map data set for
items as narrowly or broadly defined as our interests require. We assume
this premise is a valuable one, and that a hierarchical classification
approach is not just a clerical device but has functional utility.

### "Names" *versus* "modifiers"

Classification schema must distinguish clearly between *defined
earth-material names* versus *modifiers that add information to each
name*. Distinctions between names and modifiers should be incorporated
into the architecture of the data fields and relational tables that
support digital geologic-map databases, rather than into the rock names
themselves.

### Clarity and ease of use

Data-producer and the data-user both must understand clearly the basis
for the SLTT classification schema, and must be able to use them easily
and comfortably.

### Robust yet flexible

SLTT deliberations led to considerable tension between "top-down"
requirements for database uniformity on the one hand, and "bottom-up"
requirements for individual scientific expression on the other. We saw
the need for a balanced approach that accommodated some unifying
structure (robustness) yet maintained some degree of individual control
over the science content of a geologic-map database (flexibility):

(1) To be *robust*, language definitions must be clear and unambiguous,
    and parent-child relations among categories must be logical and
    based on common sense;

(2) To be *flexible*, the classification structure should not paint the
    data-producer into a corner at high levels of the classification:
    the schema must allow the field geologist and map compiler to move
    fairly deep into the classification hierarchies before feeling
    constrained by narrowly-defined terms whose meaning might be more
    stringent than the data-producer intends.

(3) To be even *more flexible*, the classification structure should
    allow the mapping geologist to use the SLTT science-language
    standards to build a "local favorites list" using concepts and terms
    defined in the standard. Thus, even though terms like "black shale"
    or "mangerite" or "arkosic sandstone" may not be defined in the
    standard, a local favorites list could contain these terms mapped
    into the SLTT science-language structure in the following fashion
    (Table 4.4.6.1):

  ------------ ----------------------- ----------------- --------------- ---------------
  **Rules and                                                            
  procedures                                                             
  for building                                                           
  a "local                                                               
  favorites                                                              
  list"                                                                  
  defined                                                                
  using                                                                  
  SLTTS_1.0                                                              
  science                                                                
  concepts and                                                           
  science                                                                
  language**                                                             

  **Local      **Local meaning**       **SLTT concept    **SLTT concept  **SLTT concept
  term**                               1**               2**             3**

  black shale  Fissile claystone       *grain size*      *depositional   *composition*
               containing abundant     (specify          fabric*         (specify amount
               organic matter          clay:silt:sand    (specify        and type of
                                       ratio)            fissile fabric) organic
                                                                         content)

  mangerite    A charnockitic plutonic *modal            *plutonic       *genesis*
               rock equivalent to an   mineralogy*       family*         (specify
               orthopyroxene-bearing   (specify pyroxene (specify        plutonic
               monzonite               modal percent)    monzonite)      igneous)

  arkosic      A terrigenous-clastic   *grain size*      *depositional   *composition*
  sandstone    rock having \< 0.01%    (specify          fabric* (fabric (specify amount
               gravel-size grains and  mud:sand:gravel   attributes not  of feldspar
               containing a            ratio)            part of the     content)
               significant amount of                     default         
               feldspar grains                           definition)     
  ------------ ----------------------- ----------------- --------------- ---------------

> Table 4.4.6.1

In order for the flexibility of (3) to be accommodated, four mutually
supportive concepts need to be agreed to and implemented:

-   Data-entry software tools for the map maker should support the
    functionality of creating a local favorites list;

-   To be compatible with SLTT terminology, lithology terms in a "local
    favorites list" should be formally defined using science concepts
    and language laid out in the SLTT standard, and using data fields
    equivalent to those defined in the NADM data-model standard (North
    American Data Model Steering Committee, 2004).

-   The map maker should "contractually" agree to define his or her
    terms using the science concepts and science language provided by
    the standard;

-   software tools that query the database should allow map users to
    specify or indicate clearly what they are searching for, and be able
    to execute database queries using their own definitions of earth
    materials and their attributes.

### Compliance with North American traditions

Earth-material names and parent-child relations among them must make
sense according to common North American practice.

## Does genesis play a role in earth-material classification?

High-level categories in the SLTT earth-material classification---e.g.,
sedimentary, volcanic, composite-genesis, metamorphic, impact
metamorphic, hydrothermally altered, mylonite-series, and
cataclastic---fundamentally are genetic: they reflect how earth material
was formed (genetic process, deformation style, crustal depth, etc.).
Obviously, the origin and geologic history of earth materials are
important to most geologic-map users, and should be recorded in
appropriate tables and data fields in the geologic-map database. Except
for these high-level categories, SLTT did not use genesis as a factor in
taxonomic classification because it is so interpretive. In any event,
many map users are interested in the physical characteristics of earth
materials, rather than their genesis. Hence, SLTT generally avoids the
use of genetic factors in its classification schema, especially at
deeper levels where classification categories are based on what the
mapping geologist can see in the outcrop (empirical factors such as
composition, structure, and texture).

## A final philosophical caveat

The use of standardized science language in digital geologic-map
databases is a new frontier that is likely to evolve with time and
experience. With this in mind, we are developing classifications of
earth materials that we believe reflect not only how mapping geologists
view them but also how such materials might be queried and analyzed in
geologic-map databases. No single classification of earth materials will
please all workers. However, the schemes we propose hopefully will be
clearly understandable, internally consistent, and usable by both
data-producer and data-user.

# WHAT HAS SLTT ACCOMPLISHED?

## Working documents *versus* a "standard"

As originally envisioned by the NADMSC and by the SLTT charter (Appendix
1), our intent was to develop formal science-language standards for
evaluation and use by the North American geologic-mapping community.
Based on the charter and early discussions among SLTT members, it seemed
logical to pursue the following strategy:

-   develop formal science-language standards for the major classes of
    earth materials (metamorphic, plutonic, sedimentary, and volcanic);

-   submit the standards for peer review and for simultaneous release as
    official publications of the U.S. Geological Survey and the
    Geological Survey of Canada;

-   upon publication of the formal standard, obtain peer review and
    feedback from the North American geologic-mapping community;

-   use this feedback to revise and refine the standard through a
    stewardship process maintained by the NADMSC and its
    science-language teams;

-   on an as-needed basis, archive and distribute subsequent versions of
    the science-language standard.

This strategy proved unsupportable for the following reasons:

-   Differences in philosophy among the various SLTT participants led to
    science-language approaches that differ from subgroup to subgroup,
    with the result that the SLTT documents do not have commonality of
    purpose, content, and scope;

-   Participation from a broad cross-section of U.S. and Canadian
    agencies proved elusive, and the SLTT chair became concerned that
    the SLTT documents would not be perceived as a truly North American
    science-language standard;

-   SLTT subgroup leaders concluded that technical peer-review prior to
    USGS and GSC publication would lead to significant editorial
    revision and response by the SLTT subgroups---each of which already
    was over-whelmed by the weight of its SLTT responsibilities.
    Moreover, the SLTT documents would have been completely out of
    context for the average peer reviewer not already involved in the
    science-language process or its philosophical and operational
    complexities; hence, the agency peer-review process would have been
    lengthy and difficult to execute and would have been of uncertain
    benefit;

-   The SLTT charter did not anticipate or identify science-language
    stewardship as a mandated function, including mechanisms for
    responding to community feedback and for versioning the
    science-language documents;

-   The NADM SLTT process, although sanctioned generically by various
    memoranda of understanding between the USGS, GSC, and AASG (but not
    the Canadian Provincial geological surveys), has no formal mechanism
    for communicating science-language issues and results to their
    respective agencies and downward to their geologic-mapping projects
    (for evaluation and beta testing). Until such mechanisms are defined
    and tested, it is premature to consider standardization,
    stewardship, and versioning;

-   In short, the SLTT process does not have the mandate or the
    personnel to execute a formal science-language process on behalf of
    the various North American federal, state, and provincial agencies
    that conduct geologic mapping.

For these reasons, the NADMSC accepted the SLTT chair's recommendation
that formal publication of the science-language document be
re-considered. NADMSC agreed that the best approach was to post the
various SLTT reports on the NADM website, and to present them as a work
in progress (i.e., as "working documents"). This strategy allows the
SLTT to conclude its responsibilities, and to present the North American
geologic-mapping community with a range of science-language approaches
and issues for their evaluation and discussion---pursuant to any next
steps in the science-language process that are determined necessary by
the NADMSC or by any geological survey.

### Composite-genesis SLTT

Science language for metamorphic rocks and for other earth materials
that form through modification of pre-existing earth material owing to
the effects of temperature, pressure, and deformation, is discussed by
the SLTT report on composite-genesis materials (North American Geologic
Map Science Language Technical Team, 2004a). The domain of this
classification system includes metamorphic rocks as commonly understood,
as well as impact metamorphic rocks, hydrothermally altered rocks,
mylonite-series rocks, and cataclastic rocks. These composite-genesis
rocks are classified according to descriptive properties that are
interpreted to reflect processes that made the rock composite.

Subgroup members discussed whether or not to include within the
composite-genesis domain earth material like pedogenic soil that forms
at the earth's surface through low temperature-pressure processes that
modify pre-existing sediment and rock. No consensus was reached on this
subject, hence pedogenic materials currently do not have a home in any
of the SLTT science-language documents, except as a modifier to describe
the upper surface of sedimentary earth materials.

### Plutonic SLTT

Owing to conflicting agency science-project obligations, members of the
plutonic SLTT subgroup were unable to conclude their deliberations and
were unable to develop plutonic science-language standards for use by
geologic-mapping projects in North America. In the interim, the NADMSC
recommends that the British Geological Survey report on plutonic science
language (Gillespie and Styles, 1999) be used for North American
geologic-map databases.

### Sedimentary SLTT

The sedimentary subgroup produced a comprehensive analysis of the
attributes for sedimentary earth materials (North American Geologic Map
Science Language Technical Team, 2004b) that includes the following
components:

-   attempts to identify from a database point of view the essential
    science concepts that underlie sedimentary terminology;

-   science language for the various lithologic classes of sedimentary
    earth material;

-   science language for the physical properties of sedimentary earth
    materials, including outcrop characteristics, consolidation state,
    sedimentary structures, sedimentary texture and fabric, particle
    composition, and material strength;

-   science language for upper-surface attributes of sedimentary earth
    materials, including depositional and erosional landform features
    and surface-modification features (e.g., surface smoothing, surface
    dissection, surface armoring, particle weathering, pedogenic
    modification, cryogenic modification, and microrelief);

-   science language for the genesis of sedimentary earth materials,
    including particle origin, depositional process, depositional place,
    geomorphic configuration, ambient conditions, and tectonic setting
    and basin type;

-   science language for human-affected landscapes, including made
    ground and worked ground.

### Volcanic SLTT

The volcanic SLTT document (North American Geologic Map Science Language
Technical Team, 2004c), provides a concise look at the science language
of unconsolidated and consolidated volcanogenic earth materials. The
goal of the volcanic team was:

> "\...to develop standardized nomenclature for use in digital geologic
> map databases, specifically to describe lithologies in volcanic rock
> units. Although this nomenclature takes the form of a hierarchy of
> terms, it is important to note that this is not the same as a formal
> rock-naming system\....
>
> We consider it critical to remember that the purpose of our
> hierarchical subdivision of terms is to describe the *lithologic
> characteristics* of *geologic map units*. \[Our hierarchical
> subdivision\] is to be used to logically retrieve or select those map
> units that contain a specified set of lithologic characteristics.
> Thus, it must be flexible enough to accommodate the extremely varied
> and unsystematic way in which map units are described and defined by
> various authors. This report groups lithologic features necessary to
> adequately characterize **volcanic materials** in the map units of a
> geologic map database into three fundamental classes based on
> **composition, texture**, and **emplacement characteristics**.
>
> No one of these classes is primary, and any or all may be used to
> select the lithologies of map units. The subdivision of any one of the
> fundamental classes consists of a list of words, arranged in a
> hierarchy that can be used to select lithologies. The words that
> describe these subdivisions are not given formal definitions here, but
> brief descriptions are given in the appendices. Many of the words have
> multiple, sometimes conflicting definitions and have been used
> differently over the years by different map authors. We have attempted
> to make the hierarchy sufficiently comprehensive, especially at the
> higher levels, to allow adequate lithologic characterization and to
> accommodate the vast majority of lithologic descriptions on existing
> geologic map legends."

The volcanic SLTT subgroup focused on how to bring the variable and
inconsistent usage of legacy geologic maps into a modern database. To
accomplish this, they characterize volcanic materials using three
fundamental classes: *composition*, *texture*, and *emplacement
characteristics*. The volcanic report provides informal
characterizations of volcanogenic materials in terms of these three
aspects, but does not provide formal material descriptions, deferring
instead to other sources (such as Le Maitre and others, 2002). The
report does not provide a comprehensive listing of petrologic
descriptors, as the subgroup felt that this was beyond their mandate.

## Have we learned anything from the SLTT process?

The SLTT process was an experiment with mixed outcomes:

-   We produced documents that can be evaluated for their contribution
    to the science content and increased uniformity of North American
    geologic-map databases;

-   However, committee deliberations revealed deep differences in how
    various individuals, agencies, and scientific programs view
    geologic-map databases and how they should be constructed to further
    their science missions.

We believe the SLTT documents will be of significant value to the North
American geologic-mapping community: hopefully, they will stimulate
discussion about how the information content of geologic-map databases
is used, how it is accessed, and how it can be structured and
represented through the use of standard science language. Such
discussions hopefully will lead to future work that will build on SLTT
accomplishments.

Based on our experience, we offer the following recommendations to
high-level science managers in agencies that execute geologic mapping:

(1) understand and appreciate the fundamental importance and
    intellectual complexity of a geologic-map data-model standard and
    its scientific content;

(2) require your agencies to develop such a standard, or to adapt and
    build on and adapt the SLTT standard;

(3) encourage the your scientific workforce to participate fully and
    legitimately in standard's development, and to implement the
    standards once they are developed;

(4) mandate and empower a single entity within your agency to take the
    lead on standards development on behalf of all other producers and
    users of geologic-map information within your agency.

If these four requirements are not advocated and facilitated, then
science-language standards will be neither robust nor comprehensive, and
most likely they will not be viewed seriously by a workforce that may
(or may not) be asked to adopt them.

# SUMMARY OF SCIENCE-LANGUAGE CLASSIFICATIONS

In parallel with the NADMSC Data Model Design Team, SLTT defines the
highest level in the classification hierarchy as "earth material":

*Earth Material*---A naturally occurring substance formed in or on the
Earth by physical, chemical, or biogenic processes that produce solid
particles or crystals of mineral and (or) rock[^3].

SLTT organizes earth materials into the following high-level hierarchy:

> Earth Material
>
> Igneous earth material
>
> Volcanic rock
>
> lithologic class based on composition
>
> lithologic class based on texture
>
> lithologic class based on emplacement characteristics
>
> Hypabyssal rock (BGS classification, Gillespie and Styles, 1999)
>
> Plutonic rock (BGS classification, Gillespie and Styles, 1999)
>
> Composite-genesis earth material
>
> Cataclastic rock
>
> Impact-metamorphic material
>
> Metamorphic rock (traditional sense) (including hydrothermally-altered
> rock)
>
> granoblastic rock
>
> foliated metamorphic rock
>
> Sedimentary earth material (unconsolidated, consolidated)
>
> Sedimentary material, unclassified
>
> Terrigenous-clastic sedimentary material
>
> Carbonate sedimentary material
>
> Organic-rich sedimentary material
>
> Non-clastic siliceous sedimentary material
>
> Noncarbonate-salt sedimentary material
>
> Phosphate-rich sedimentary material
>
> Iron-rich sedimentary material

## Igneous earth material

The science language of igneous materials was addressed by two SLTT
subgroups, one dealing with *volcanic igneous materials* and the other
dealing with *plutonic igneous materials*. In one sense this subdivision
is arbitrary, as the processes, compositions, and textures of the two
igneous families overlap. However, the accumulation of many volcanic
materials at the Earth's surface yields geologic products having unique
geomorphic, compositional, and textural attributes; accordingly, SLTT
developed science language for volcanic materials separately from
plutonic materials.

### Plutonic earth material

SLTT science language for plutonic earth materials adopts the BGS
classification scheme for plutonic rocks (Gillespie and Styles, 1999)
that is based on material names recommended by the IUGS (IUGS, 1973;
Streckeisen, 1974, 1976, 1978, 1979; Le Bas and others, 1986; Le Maitre
and others, 1989; Le Bas and Streckeisen, 1991). SLTT did not produce a
report on plutonic materials.

### Volcanic earth material

SLTT science language for volcanic earth materials is structured around
four concepts:

> Material name based on *modal composition*
>
> 1.0 Felsic (high-silica) volcanic material
>
> 1.1 rhyolite
>
> 1.2 rhyodacite
>
> 1.3 dacite
>
> 1.4 trachydacite
>
> 1.5 trachyte
>
> 2.0 Mafic (low-silica) volcanic material
>
> 2.1 andesite
>
> 2.2 basaltic andesite
>
> 2.3 basalt
>
> 2.4 trachyandesite
>
> 2.5 trachybasalt
>
> 3.0 Ultramafic volcanic material
>
> 3.1 picrobasalt
>
> 3.2 picrite
>
> 3.3 komatiite
>
> 4.0 High-alkali volcanic material
>
> 4.1 alkali rhyolite
>
> 4.2 alkali trachyte
>
> 4.3 phonolite
>
> 4.4 tephriphonolite
>
> 4.5 phonotephrite
>
> 4.6 tephrite
>
> 4.7 basanite
>
> 4.8 basalt
>
> 4.9 foidite
>
> 5.0 Volcanic carbonatite
>
> 6.0 Lamprophyre

Deeper-level volcanic names based on composition derive from
recommendations by the IUGS (IUGS, 1973; Streckeisen, 1974, 1976, 1978,
1979; Le Bas and others, 1986; Le Maitre and others, 1989; Le Bas and
Streckeisen, 1991).

> Material name based on *texture*
>
> 1.0 Unconsolidated volcanic material
>
> 1.1 ash
>
> 1.2 lapilli-ash
>
> 1.3 lapilli
>
> 1.4 block-ash
>
> 1.4 blocks
>
> 1.4 bombs
>
> 1.4 scoria
>
> 1.5 pumice
>
> 2.0 Consolidated volcanic material
>
> 2.1 fragmental volcanic rock
>
> 2.1.1 tuff
>
> 2.1.2 lapilli tuff
>
> 2.1.3 lapillistone
>
> 2.1.4 tuff breccia
>
> 2.1.5 pyroclastic breccia
>
> 2.1.6 agglomerate
>
> 2.2 lava rock
>
> 2.2.1 vitric lava
>
> 2.2.1.1 obsidian
>
> 2.2.1.2 vitrophyre
>
> 2.2.1.3 pitchstone
>
> 2.2.1.4 perlite
>
> Material name based on *genesis*
>
> 1.0 Intrusive volcanic rock
>
> 1.1 volcanic dike
>
> 1.2 volcanic sill
>
> 1.3 volcanic laccolith
>
> 1.4 volcanic stock
>
> 1.5 volcanic plug
>
> 1.6 intrusive volcanic breccia
>
> 2.0 Extrusive volcanic rock
>
> 2.1 lava flow
>
> 2.1.1 pillow lava
>
> 2.1.2 pahoehoe
>
> 2.1.3 aa
>
> 2.1.4 block lava
>
> 2.1.5 massive lava
>
> 2.2 lava dome
>
> 2.3 stratocone
>
> 2.4 shield volcano
>
> 3.0 Volcaniclastic material
>
> 3.1 pyroclastic material
>
> 3.1.1 pyroclastic flow
>
> 3.1.2 pyroclastic surge
>
> 3.1.3 pyroclastic fall
>
> 3.1.3.1 agglutinate (spatter)
>
> 3.1.3.2 ejecta blanket
>
> 3.1.3.3 cinder cone
>
> 3.1.3.4 tuff cone
>
> 3.1.3.5 tuff ring

## Composite-genesis rocks and rock particles

As defined in the SLTT classification, composite-genesis earth material
is any earth material having observable features that document
mineralogical, chemical, or structural change of a preexisting earth
material essentially in the solid state. The category includes
metamorphic rocks (*sensu strictu*), hydrothermally altered rocks,
cataclastic rocks, and impact-metamorphic rocks. Weathered rock and
pedogenic soil also could be considered composite-genesis materials, but
SLTT has not included these materials in the development of the
classification. Where possible, the British Geological Survey
classification of metamorphic rocks (Robertson, 1999) and preliminary
recommendations of the IUGS Subcommission on the Systematics of
Metamorphic Rocks (SCMR) (Schmid and others, 2002) were adapted to meet
SLTT database requirements.

Composite-genesis rocks are classified along two orthogonal dimensions,
fabric and composition. Because both of these dimensions are
hierarchical (Text-figures 1 and 2), the class hierarchy for
composite-genesis rocks is a directed acyclic graph rather than a tree.
Classes that have both composition and fabric criteria are 'children' of
both a 'composition' parent and a 'fabric' lithology parent. Actual
class names for rocks have a *fabric* component (such as schist) and a
*compositional* component (such as marble or quartzofeldspathic).

![](media/image1.wmf){width="5.997916666666667in" height="3.88125in"}

Text-figure 1---Simplified hierarchy of fabric-based composite-genesis
rock names

![](media/image2.wmf){width="5.995138888888889in"
height="1.8270833333333334in"}

Text-figure 2---Simplified hierarchy of composition-based
composite-genesis rock name terms

### Metamorphic rock (traditional sense)

A metamorphic rock has observable features that document change after
the original formation of the rock, under physical or chemical
conditions that differ from those normally occurring at the surface of
the Earth and in zones of cementation and diagenesis below the surface
(Smulikowski and others, 1997). The basic level of classification is the
definition of fabric-based types described as hornfels, granofels,
schist, layered gneiss, non-layered gneiss, slate, and mylonite-series
rock (Table 6.2.1). In this classification, hydrothermally altered rocks
are treated as metamorphic rocks; the full metamorphic classification is
applied to these rocks without treating them as a distinct, separate
category.

  ------------------ ----------------------------------------------------
  **Fabric-based     **Definition and scoping notes**
  Metamorphic-rock   
  Class**            

  Hornfels           A non-foliated aphanitic metamorphic rock having
                     granoblastic fabric. The term does not necessarily
                     denote a contact metamorphic origin, although that
                     is most commonly the case

  Granofels          A phaneritic metamorphic rock that has little or no
                     foliation or lineation*,* implying that that less
                     than 10% of the particles in the rock are fabric
                     elements that have an inequant shape and an aspect
                     ratio 1.5:1

  Schist             a phaneritic metamorphic rock that has well
                     developed continuous schistosity. "Well developed"
                     schistosity is defined here to mean that \>50% of
                     the rock consists of mineral grains having a
                     tabular, lamellar, or prismatic crystallographic
                     habit that are oriented in a continuous planar or
                     linear fabric (Jackson, 1997). Continuous is defined
                     to mean that domains lacking the fabric are \<1 cm
                     thick if they are layers, and \<5 cm in diameter if
                     they are irregular patches, and constitute \<25% of
                     the rock. Phyllite is a fine-grained subclass of
                     schist having an average grain size between 0.25 mm
                     and 0.1 mm and a silvery sheen.

  Layered gneiss     a foliated, phaneritic rock that lacks well
                     developed, continuous schistosity and has laterally
                     continuous compositional layering \> 5 mm thick

  Non-layered gneiss a foliated, phaneritic rock that lacks both well
                     developed, continuous schistosity and laterally
                     continuous compositional layering \> 5 mm thick.
                     "Laterally continuous" here means that layers
                     defining the foliation can be traced \> 10 cm
                     (length of lateral continuity)

  Slate              an aphanitic rock that has well developed
                     schistosity (Brodie and others, 2002). The
                     definition of schistosity used in this
                     classification requires that \>50% of the rock
                     consists of mineral grains having a tabular,
                     lamellar, or prismatic crystallographic habit that
                     are oriented in a continuous planar or linear
                     fabric. In an aphanitic rock this determination is
                     generally based on indirect evidence, which is
                     typically the presence of slaty cleavage, and the
                     sheen observed on parting surfaces due to alignment
                     of tiny phyllosilicate grains. An average grain size
                     that is aphanitic (\<0.1 mm), except for
                     porphyroblasts, is specified for precision.

  Mylonite-series    displays a foliation defined by the shapes of
  rock               deformed mineral grains or grain aggregates having
                     aspect ratios \> 1.5:1, \>10% of the rock is
                     composed of "matrix" showing evidence of tectonic
                     reduction in grain size, and the foliation and
                     matrix have observable features that document
                     continuous, crystal-plastic deformation.
                     Mylonite-series rock is subdivided according to
                     matrix percentages into protomylonite, mylonite, and
                     ultramylonite (Sibson, 1977)
  ------------------ ----------------------------------------------------

Table 6.2.1---Fabric-based metamorphic-rock classes

Composition-based rock classes include amphibolite, marble, and common
monomineralic rocks such as quartzite and serpentinite, which are
defined individually by modal mineral composition. Other monomineralic
metamorphic rocks consisting predominantly (\>75%) of a single mineral
are classified as monomineralic-granofels, monomineralic-hornfels,
monomineralic-schist, etc., depending on the fabric. Composition
qualifiers defined on the basis of modal mineralogy (ferromagnesian,
calcsilicate, carbonate, pelitic, semipelitic, quartzofeldspathic; see
Table 6.2.2) are combined with a fabric term as in "pelitic schist."
Traditional non-systematic rock terms such as amphibolite that are based
on modal mineralogy are also treated as composition qualifier terms.
This classification leans towards a minimum of special rock names for
unusual composition rocks, and such rocks would be assigned a 'special
composition' qualifier. The uncontrolled rock-name field in the database
is available to assign any special rock name the geologist may prefer.

  -------------------- -------------------------------------------------------
  **Composition        **Definition**
  qualifiers**         

  amphibolite          Rock consists of \>75% green, brown, or black amphibole
                       plus plagioclase (including albite) and amphibole \>30%
                       (modal) of whole rock, and amphibole \>50% of total
                       mafic constituents

  argillic             Rock is apparently clay-rich. Use for aphanitic rocks

  calcareous           Rock reacts to form bubbles when hydrochloric acid is
                       applied. Use for aphanitic rocks (e.g. hornfels)

  calcsilicate         Rock consists of 50% calcsilicate or carbonate minerals
                       and carbonate minerals ≤ calcsilicate minerals in
                       mineral mode

  ferromagnesian       Rock consists of \>40% dark ferromagnesian minerals.
                       Standard term defined by Bates and Jackson (1987) to
                       mean \"containing iron and magnesium\"

  impure marble        Rock consists of \>50% calcsilicate or carbonate
                       minerals and relative proportion of calcsilicate and
                       carbonate minerals is unknown or not specified

  mafic                Rock consists of 40% and \<90% ferromagnesian minerals

  marble               Rock consists of \> 75% carbonate minerals

  metacarbonate        Rock consists of \>50% calcsilicate or carbonate
                       minerals and carbonate minerals \> calcsilicate
                       minerals in mineral mode

  monomineralic        Rock consists of \>75% of a single mineral species and
                       does not meet any of the other composition terms (e.g.
                       quartzite, calcite marble, dolomite marble,
                       serpentinite...)

  pelitic              Rock for which the sum of modal quartz+feldspar+ mica +
                       aluminous mineral is 70%, and aluminous mineral + mica
                       content is 40%

  quartzite            Rock consists of 75% quartz

  quartzofeldspathic   Rock for which the sum of modal quartz+feldspar+ mica +
                       aluminous mineral is 70%, and quartz + feldspar (sensu
                       Robertson, 1999) \>60%

  semipelitic          Rock for which the sum of modal quartz+feldspar+ mica +
                       aluminous mineral is 70%, and quartz+ feldspar \< 60%

  silicic              Rock is apparently silica-rich. Use for aphanitic
                       rocks. Jackson (1997) includes denotation of igneous
                       origin. For SLTT classification, should be considered
                       to mean \"appears to consist largely of quartz and
                       feldspar\", generally is aphanitic with hardness \>= 6.

  special composition  Rock has a mineral composition that doesn\'t fit in any
                       defined composition class. A modal mineral description
                       is essential. The rock consists of \<40% ferromagnesian
                       minerals and \<50% carbonate + calcsilicate minerals
                       and \<70% Q+Fs + mica + aluminous minerals

  ultramafic           Rock consists of \>90% ferromagnesian minerals
  -------------------- -------------------------------------------------------

Table 6.2.2---Selected composition-based classes (qualifiers) for
metamorphic rocks

The SLTT classification of metamorphic rocks does not apply the 'meta'
prefix to a protolith name (as in metasiltstone), because it cannot be
simply integrated into a classification based on fabric and composition,
and because interpretations of protolith can be highly subjective. Rock
name terms in the form 'meta-(*some rock name*)' can be placed by the
user in an uncontrolled rock name field and can also appear in a user
interface by having underlying software that maps the name assignment to
the implied dual classification. Where the protolith can be determined,
the classification includes two distinct parts---a protolith
classification using the criteria applicable to the protolith lithology,
and a composite-genesis classification based on the fabric and
composition criteria outlined here. The data model design should include
a mechanism that allows the 'dominant' aspect of a rock that has
multiple classifications to be specified.

### Cataclastic rock

SLTT classifies a rock as cataclastic if \>10% of the volume consists of
fragments bounded by fractures. Cataclastic rocks are further classified
based on the presence or absence of primary cohesion, the percentage of
broken fragments large enough to be visible, and the amount of
fragmental cataclastic matrix (Sibson, 1977; Snoke and Tullis, 1998)
Cataclastic rock having evidence of primary cohesion is subdivided
according to matrix percentages into *protocataclasite*, *cataclasite*,
and *ultracataclasite* (Sibson, 1977). Cataclastic rock that lacks
primary cohesion is subdivided into fault breccia (visible fragments
\>30% of rock) and gouge (visible fragments \<30%).

### Impact-metamorphic rock

Impact-metamorphic rocks have observable features, such as microscopic
planar deformation features, that are unequivocally the result of shock
metamorphism (Stöffler and Grieve, 2001), high-pressure minerals, or
field evidence such as shatter cones and crater structure. Adapting
Stöffler and Grieve's (2001) IUGS recommendations with slight
modifications, impact-metamorphic rock is classified as shocked rock,
impact melt rock, or impact breccia.

## Sedimentary earth material

The SLTT Sedimentary Subgroup developed science language for the
lithologic classification (material name), physical characteristics, and
origin and depositional history of sedimentary materials.

At the top hierarchical level, sedimentary earth materials are
classified into eight categories based on sediment composition (Table
5.3.1). At a high level, unconsolidated sediment is distinguished from
consolidated rock, and separate (but parallel) naming schemes are
developed for each consolidation state.

  --------------------- -----------------------------------------------------
  **Sedimentary         **Definition**
  material              
  (unconsolidated,      
  consolidated)**       

  Sedimentary material, Not enough information is known about a sedimentary
  unclassified          material to classify it as anything other than
                        sedimentary rock or sediment, unclassified

  Terrigenous-clastic   A rock or sediment composed principally of broken
  sedimentary material  fragments that are derived from the land or
                        continent. To be considered as terrigenous-clastic, a
                        rock (sediment) must have ≥ 50% of its constituents
                        derived from the land or continent

  Carbonate sedimentary Sediment or sedimentary rock ≥50% of whose primary
  material              and (or) re-crystallized constituents are composed of
                        carbonate minerals (calcite, aragonite, dolomite). By
                        definition, such materials are *intra-basinal* in
                        origin---that is, they formed by processes operating
                        within the depositional regime, and were not
                        transported into that regime from other sediment
                        sources

  Organic-rich          Sedimentary materials having sufficiently high
  sedimentary material  organic content that they can not be identified as
                        another kind of sedimentary rock (e.g.,
                        terrigenous-clastic or carbonate). Pragmatically,
                        SLTT places this threshold at ≥50% organic content by
                        weight to be consistent with the established
                        definition for coal without conflicting with
                        definitions of other compositionally-based categories

  Non-clastic siliceous Sedimentary materials dominated by non-clastic silica
  sedimentary material  are those composed of ≥50% silica of biogenic or
                        chemical origin (Hallsworth and Knox, 1999, p. 21)

  Noncarbonate-salt     Sedimentary materials dominated by non-carbonate
  sedimentary material  salts are those whose primary constituents consist of
                        chloride, sulphate, or borate minerals. Such
                        materials also are known as *evaporite* materials
                        because they form through evaporative precipitation
                        of mineral salts from brines---either directly from
                        the water column or from pore fluids during
                        diagenesis

  Phosphate-rich        Phosphatic sedimentary materials are those in which
  sedimentary material  phosphate minerals or phosphatic components comprise
                        \>50% of the sedimentary framework as determined by
                        hand-lens or petrographic analysis (Hallsworth and
                        Knox, 1999). This corresponds with a rock (sediment)
                        typically containing ≥ 15% P~2~O~5~ (by weight)

  Iron-rich sedimentary Iron-rich sedimentary materials are those in which
  material              iron-bearing minerals comprise ≥ 50% of the
                        sedimentary framework as determined by hand-lens or
                        petrographic analysis (Hallsworth and Knox, 1999).
                        This corresponds with a rock (sediment) typically
                        containing ≥ 15% iron (by weight)
  --------------------- -----------------------------------------------------

Table 5.3.1.

Within each compositional category, lower-level, more detailed material
names are based on textural or compositional criteria (or both),
depending on the parental category.

The distinction between "unconsolidated" and "consolidated" (sediment
*versus* rock) occupied considerable SLTT discussion and attention. We
concluded that SLTT can suggest guidelines for distinguishing
unconsolidated from consolidated materials. However, ultimately it will
be the subjective decision of the data producer as to whether a specific
sedimentary material is "consolidated" or "unconsolidated" according to
his or her judgment. Table 5.3.2 provides guidelines that can facilitate
this determination.

  -------------------- --------------------- -------------------------- -----------------
                       **Consolidation       **Field criterion**        **Relative
                       state**                                          density**
                                                                        (D~r~)[^4]

  **Unconsolidated**   Very slightly         Easily indented with       0.00---0.20
                       consolidated          fingers                    

                       Slightly consolidated Somewhat less easily       0.20---0.40
                                             indented with fingers.     
                                             Easily shoveled            

                       Moderately            Shoveled with difficulty   0.40---0.70
                       consolidated                                     

  **Consolidated**     Well consolidated     Requires pick to loosen    0.70---0.90
                                             for shoveling              

                       Lithified             Requires blasting or heavy 0.90---1.00
                                             equipment to loosen        

                       Indurated             Rings to the blow of a     1.00
                                             hammer                     
  -------------------- --------------------- -------------------------- -----------------

Table 5.3.2

SLTT developed science language for a variety of attributes that
characterize the outcrop appearance of sedimentary materials (Table
5.3.3):

  ------------------- --------------- --------------------------------------------------
  **Outcrop                           
  characteristics**                   

  **Science concept**                 **Data-field content**

  Lithotope abundance                 indicates the relative abundance of each lithotope
                                      in an outcrop

  Map-unit                            describes how a map unit crops out (prominent,
  geomorphology                       subdued)

  Outcrop profile                     describes how individual lithotopes crop out
                                      (ledge-forming, slope-forming, etc.)

  Outcrop weathering                  describes how sedimentary materials weather
                                      (cavernous, friable, etc.)

  Material color      Color (fresh)   describes the color of fresh geologic materials

                      Color           describes the color of weathered geologic
                      (weathered)     materials

                      Color (dry)     describes the color of dry geologic materials

                      Color (wet)     describes the color of wet geologic materials

  Consolidation state                 describes how firm and knitted together a
                                      sedimentary material is, and how hard it is once
                                      it has been lithified
  ------------------- --------------- --------------------------------------------------

Table 5.3.3

SLTT classifies sedimentary structures into primary and secondary
structures, with the following major categories (Table 5.3.4):

+-----------------------------------------------------------------------+
|                                                                       |
+-----------------------------------------------------------------------+
| PRIMARY SEDIMENTARY STRUCTURE                                         |
+-----------------------------------------------------------------------+
| Inorganic sedimentary structure                                       |
+-----------------------------------------------------------------------+
| > Syngenetic structure                                                |
+-----------------------------------------------------------------------+
| > Depositional structure                                              |
+-----------------------------------------------------------------------+
| > Erosional structure                                                 |
+-----------------------------------------------------------------------+
| > Penecontemporaneous structure                                       |
+-----------------------------------------------------------------------+
| > Bed-surface structure                                               |
+-----------------------------------------------------------------------+
| > Within-bed structure                                                |
+-----------------------------------------------------------------------+
| > Multi-bed structure                                                 |
+-----------------------------------------------------------------------+
| Biogenic sedimentary structure                                        |
+-----------------------------------------------------------------------+
| SECONDARY SEDIMENTARY STRUCTURE                                       |
+-----------------------------------------------------------------------+
| Secondary deformation structure                                       |
+-----------------------------------------------------------------------+
| Sedimentary hardground                                                |
+-----------------------------------------------------------------------+
| Dissolution structures                                                |
+-----------------------------------------------------------------------+
| Epigenetic growth structure                                           |
+-----------------------------------------------------------------------+
| UNCLASSIFIED SEDIMENTARY STRUCTURE                                    |
+-----------------------------------------------------------------------+
| Bed-surface structure                                                 |
+-----------------------------------------------------------------------+
| Within-bed structure                                                  |
+-----------------------------------------------------------------------+
| Multi-bed structure                                                   |
+-----------------------------------------------------------------------+

Table 5.3.4

SLTT developed science language for a variety of attributes that
characterize the fabric and texture of sedimentary materials (Table
5.3.5):

  --------------- ------------------- --------------------------------------------
  **Sedimentary                       
  fabric and                          
  texture                             
  elements**                          

  **Science                           **Data-field content**
  concept**                           

  Preservation of                     Yes or no (character field)
  depositional                        
  fabric                              

  Grain-support                       indicates whether fabric is clast-supported
  *versus* matrix                     or matrix-supported
  support                             

  Particle size   Matrix grain size   indicates range of matrix grain size
                  (range)             

                  Matrix grain size   indicates mean of matrix grain size
                  (average)           

                  Particle grain size indicates range of particle grain size
                  (range)             

                  Particle grain size indicates mean of particle grain size
                  (average)           

  Particle                            indicates sorting in terms of Inclusive
  sorting                             Graphic Standard Deviation (Folk, 1968)

  Particle shape                      indicates the shape of grains and clasts
  and rounding                        (rounded, subangular, tabular, spherical,
                                      etc.)

  Coated                              indicates the fabric type created by
  particles                           particle coating (ooidal, pisoidal,
                                      oncoidal)

  Particle                            indicates the geometric orientation of
  orientation                         elongate or disk-shaped particles

  Particle                            indicates the spacing or density patterns of
  packing                             particles as expressed by nature of grain
                                      contacts
  --------------- ------------------- --------------------------------------------

Table 5.3.5.

SLTT classified sedimentary genesis according to a scheme that
integrates three attributes: Table 5.3.6 lists the science concepts that
SLTT used to guide the development of sedimentary-genesis terms. These
concepts suggest that genetic information about sedimentary materials in
geologic-map databases should be scalable, hierarchical, and
multi-faceted.

  --------------------------- -------------------------------------------
  **Science Concept**         **Meaning**

  Particle origin             How a particle of sediment originally was
                              produced

  Depositional process        How a sediment volume was transported and
                              deposited

  Depositional place          Where a sediment was deposited

  Geomorphic (physiographic)  How process and place have interacted to
  configuration               yield a geomorphic configuration
                              recognizable on the Earth's surface

  Ambient conditions          Information about climatic conditions,
                              depositional slope, distance from source
                              area, oxygen levels at depositional site,
                              etc.

  Tectonic setting and basin  Plate-tectonic setting of the depocenter
  type                        within which sedimentary materials
                              accumulate
  --------------------------- -------------------------------------------

Table 5.3.6

Ultimately, it is the interaction between *depositional process* and
*depositional environment* that yields a *depositional product*. This
interaction can be viewed as a two-dimensional matrix in which process
is arrayed against place (Table 5.3.7):

+-----+---+--------------+------+------+------+------+------+-------+
|     |   |              | **P  |      |      |      |      |       |
|     |   |              | HYSI |      |      |      |      |       |
|     |   |              | OGRA |      |      |      |      |       |
|     |   |              | PHIC |      |      |      |      |       |
|     |   |              | S    |      |      |      |      |       |
|     |   |              | ETTI |      |      |      |      |       |
|     |   |              | NG** |      |      |      |      |       |
|     |   |              |      |      |      |      |      |       |
|     |   |              | (    |      |      |      |      |       |
|     |   |              | Sele |      |      |      |      |       |
|     |   |              | cted |      |      |      |      |       |
|     |   |              | hi   |      |      |      |      |       |
|     |   |              | gh-l |      |      |      |      |       |
|     |   |              | evel |      |      |      |      |       |
|     |   |              | envi |      |      |      |      |       |
|     |   |              | ronm |      |      |      |      |       |
|     |   |              | ents |      |      |      |      |       |
|     |   |              | o    |      |      |      |      |       |
|     |   |              | nly) |      |      |      |      |       |
+-----+---+--------------+------+------+------+------+------+-------+
|     |   |              | Allu | Del  | La   | P    | S    | Suba  |
|     |   |              | vial | taic | cust | laya | hore | queou |
|     |   |              | set  | set  | rine | set  | zone | s-fan |
|     |   |              | ting | ting | set  | ting | set  | se    |
|     |   |              |      |      | ting |      | ting | tting |
+-----+---+--------------+------+------+------+------+------+-------+
| **  | * | Chemogenic   |      |      |      |      |      |       |
| DEP | * | Process      |      |      |      |      |      |       |
| OSI | N |              |      |      |      |      |      |       |
| TIO | o |              |      |      |      |      |      |       |
| NAL | n |              |      |      |      |      |      |       |
| PRO | b |              |      |      |      |      |      |       |
| CES | i |              |      |      |      |      |      |       |
| S** | o |              |      |      |      |      |      |       |
|     | g |              |      |      |      |      |      |       |
| (H  | e |              |      |      |      |      |      |       |
| igh | n |              |      |      |      |      |      |       |
| -le | i |              |      |      |      |      |      |       |
| vel | c |              |      |      |      |      |      |       |
| pro | * |              |      |      |      |      |      |       |
| ces | * |              |      |      |      |      |      |       |
| ses |   |              |      |      |      |      |      |       |
| on  | * |              |      |      |      |      |      |       |
| ly) | * |              |      |      |      |      |      |       |
|     | p |              |      |      |      |      |      |       |
|     | r |              |      |      |      |      |      |       |
|     | o |              |      |      |      |      |      |       |
|     | c |              |      |      |      |      |      |       |
|     | e |              |      |      |      |      |      |       |
|     | s |              |      |      |      |      |      |       |
|     | s |              |      |      |      |      |      |       |
|     | * |              |      |      |      |      |      |       |
|     | * |              |      |      |      |      |      |       |
+-----+---+--------------+------+------+------+------+------+-------+
|     |   | Fluid-Flow   |      |      |      |      |      |       |
+-----+---+--------------+------+------+------+------+------+-------+
|     |   | G            |      |      |      |      |      |       |
|     |   | ravitational |      |      |      |      |      |       |
|     |   | Potential    |      |      |      |      |      |       |
+-----+---+--------------+------+------+------+------+------+-------+
|     |   | Glacial flow |      |      |      |      |      |       |
+-----+---+--------------+------+------+------+------+------+-------+
|     | * | Sedi         |      |      |      |      |      |       |
|     | * | ment-binding |      |      |      |      |      |       |
|     | B |              |      |      |      |      |      |       |
|     | i |              |      |      |      |      |      |       |
|     | o |              |      |      |      |      |      |       |
|     | g |              |      |      |      |      |      |       |
|     | e |              |      |      |      |      |      |       |
|     | n |              |      |      |      |      |      |       |
|     | i |              |      |      |      |      |      |       |
|     | c |              |      |      |      |      |      |       |
|     | p |              |      |      |      |      |      |       |
|     | r |              |      |      |      |      |      |       |
|     | o |              |      |      |      |      |      |       |
|     | c |              |      |      |      |      |      |       |
|     | e |              |      |      |      |      |      |       |
|     | s |              |      |      |      |      |      |       |
|     | s |              |      |      |      |      |      |       |
|     | * |              |      |      |      |      |      |       |
|     | * |              |      |      |      |      |      |       |
+-----+---+--------------+------+------+------+------+------+-------+
|     |   | Sedim        |      |      |      |      |      |       |
|     |   | ent-trapping |      |      |      |      |      |       |
+-----+---+--------------+------+------+------+------+------+-------+
|     |   | Framew       |      |      |      |      |      |       |
|     |   | ork-building |      |      |      |      |      |       |
+-----+---+--------------+------+------+------+------+------+-------+

Table 5.3.7---Two-dimensional matrix arraying *depositional process*
(left) against *physiographic setting* (right) to yield cells in which a
*depositional product* may (or may not) occur. Representative
depositional products are listed in Table 5.3.8.

In Table 5.3.7, the intersection of a genetic process with a sedimentary
environment yields a grid cell that represents a potential depositional
product. Table 5.3.8 lists representative examples of such products:

  ---------------- --------------- -------------------- ----------------- ------------------- -------------- -------------------- ------------------
                                                                                                                                  

  algal-mat        bog deposit     bar deposit          beach deposit     braided-channel     channel        chute-channel        crevasse-channel
  deposit                                                                 deposit             deposit        deposit              deposit

  crevasse-splay   debris-flow     distributary-mouth   dune deposit      fan deposit         fan deposit    fan-delta deposit    flood-plain
  deposit          deposit         bar deposit                            (subaerial)         (subaqueous)                        deposit

  glacial-till     inlet-channel   lagoon deposit       levee deposit     levee deposit       marsh deposit  meandering-channel   mud-flat deposit
  deposit          fan deposit                          (subaerial)       (subaqueous)                       deposit              

  overbank-fines   pelagic-ooze    pond deposit         reef,             reef,               sabkha deposit sand-flat deposit    sand-flat deposit
  deposit          deposit                              framework-built   sediment-trapping                                       

  sheet-flow       sheet-sand      shelf deposit        slide deposit     slope deposit       slump deposit  supratidal-flat      swamp deposit
  deposit          deposit                                                                                   deposit              

  tidal-channel    tidal-flat      tidal-inlet deposit  tidal-ridge       turbidite deposit   washover-fan                        
  deposit          deposit                              deposit                               deposit                             
  ---------------- --------------- -------------------- ----------------- ------------------- -------------- -------------------- ------------------

Table 5.3.8. Examples of depositional products.

All three genetic attributes (depositional process, depositional
environment, depositional product) can be classified hierarchically to
yield a complete description of how a sedimentary material was formed.

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Le Maitre, R.W. (editor), Streckeisen, A., Zanettin, B., Le Bas, M.J.,
Bonin, B., Bateman, P., Bellieni, G., Dudek, A., Efremova, S., Keller,
J., Lameyre, J., Sabine, P.A., Schmid, R., Sørensen, H., and Woolley,
A.R., 2002, Igneous rocks: A classification and glossary of terms:
Recommendations of the International Union of Geological Sciences
Subcommission on the Systematics of Igneous Rocks: Cambridge, Cambridge
University Press, 236 p.

MacDonald, R., 1974, Nomenclature and petrochemistry of the peralkaline
oversaturated extrusive rocks: Bulletin Volcanologique, v. 38, p.
498--516.

McMillan, A.A., and Powell, J.H., 1999, Classification of artificial
(man-made) ground and natural superficial deposits: applications to
geological maps and datasets in the UK: v. 4 of the BGS rock
classification scheme: British Geological Survey Research Report Number
RR 99-04, 65 p.

North American Geologic-map Data Model Science Language Technical Team,
2004a, Classification of metamorphic and other composite-genesis rocks,
including hydrothermally altered, impact-metamorphic, mylonitic, and
cataclastic rocks, Version 1.0 (12/18/2004): Draft report posted on the
North American Data Model webpage
\<<http://nadm-geo.org/sltt/products/sltt_composite.pdf>\>, 56 p.

North American Geologic-map Data Model Science Language Technical Team,
2004b, Sedimentary materials: science language for their classification,
description, and interpretation in digital geologic-map databases,
Version 1.0 (12/18/2004): Draft report posted on the North American Data
Model website
\<<http://nadm-geo.org/sltt/products/sedimentary/sedimentary_narrative.pdf>\>,
595 p.

North American Geologic-map Data Model Science Language Technical Team,
2004c, Volcanic materials: science language for their naming and
characterization in digital geologic-map databases, Version 1.0
(12/18/2004): Draft report posted on the North American Data Model
website \<<http://nadm-geo.org/sltt/products/sltt_volcanic.pdf>\>, 18 p.

North American Geologic Map Data Model Steering Committee, 2004, NADM
Conceptual Model 1.0---A conceptual model for geologic map information:
U.S. Geological Survey Open-File Report 2004-1334, 58 p., accessed
online at URL <http://pubs.usgs.gov/of/2004/1334>.

Robertson, S., 1999, Classification of metamorphic rocks: Volume 2 of
the BGS rock classification scheme: British Geological Survey Research
Report Number RR 99-02, 24 p.

Schmid, R., 1981, Descriptive nomenclature and classification of
pyroclastic deposits and fragments: Recommendations of the IUGS
Subcommission on the Systematics of Igneous Rocks: Geology, v. 9, p.
41--43.

Schmid, R., Fettes, D., Harte, B., Davis, E., Desmons, J., and Siivola,
J., 2002, Towards a unified nomenclature in metamorphic petrology: 1.
How to name a metamorphic rock, A proposal on behalf of the IUGS
Subcommission on the Systematics of Metamorphic Rocks, Web version of
31.07.2002: 13 p., available online at <http://www.bgs.ac.uk/SCMR>

Sibson, R.H., 1977, Fault rocks and fault mechanisms: Journal of the
Geological Society of London, v. 133, p. 191-213.

Smulikowski, Witold, Desmons, Jacqueline, Harte, Ben, Sassi, F.P., and
Schmid, Rolf, 1997, Towards a unified nomenclature of metamorphism: 3.
Types, grade and facies \[A proposal on behalf of the IUGS Subcommission
on the Systematics of Metamorphic Rocks\], compiled 1 September 1997 and
corrected 19 November 1997: 13 p., available online at
<http://www.bgs.ac.uk/SCMR>**.**

Snoke, A.W., and Tullis, J., 1998, An overview of fault rocks, *in*
Snoke, A.W., Tullis, J., and Todd, V.R., Fault-related Rocks, A
Photographic Atlas: Princeton, N.J., Princeton University Press, p.
3-18.

Stöffler, D., and Grieve, R.A.F., 2001, IUGS classification and
nomenclature of impact metamorphic rocks: Towards a final proposal
\[indexed as: Towards a unified nomenclature of metamorphism: IUGS
classification and nomenclature of impact metamorphic rocks. A proposal
on behalf of the IUGS Subcommission on the Systematics of Metamorphic
Rocks, Web version of 14.01.2001\]: 3 p., available online at
<http://www.bgs.ac.uk/SCMR>.

Streckeisen, A. 1974, Classification and nomenclature of plutonic rocks:
Recommendations of the IUGS Subcommission on the Systematics of Igneous
Rocks: Geologische Rundschau Internationale Zeitschrift für Geologie:
Stuttgart, v. 63, p. 773--785.

Streckeisen, A. 1976, To each plutonic rock its proper name: Earth
Science Reviews, v. 12, p. 1--33.

Streckeisen, A. 1978, IUGS Subcommission on the Systematics of Igneous
Rocks: Classification and nomenclature of volcanic rocks, lamprophyres,
carbonatites and melilitic rocks. Recommendations and suggestions: Neues
Jahrbuch für Mineralogie, v. 134, p. 1--14.

Streckeisen, A. 1979, Classification and nomenclature of volcanic rocks,
lamprophyres, carbonatites and melilitic rocks: recommendations and
suggestions of the IUGS Subcommission on the Systematics of Igneous
Rocks: Geology, v. 7, p. 331--335.

Struik, L.C., Quat, M.B., Davenport, P.H., and Okulitch, A.V., 2002,
Multi-hierarchical rock classification for use with thematic
computer-based query systems:, a preliminary scheme.  Geological Survey
of Canada, Current Research 2002D, 9p.

# Appendix 1 (SLTT CHARTER)

PROPOSED NORTH AMERICAN GEOLOGIC-MAP DATA MODEL

SCIENCE-LANGUAGE TECHNICAL TEAM CHARTER

11/1/99

[Executive Statement]{.underline}.---See the Data Model Steering
Committee (DMSC) charter for an executive statement on technical teams.

**MANDATE AND CHARGE**

[Mandate]{.underline}.---The Science Language Technical Team (SLTT) is
mandated to develop standardized nomenclature for digital geologic-map
databases---including (but not limited to) the following areas:

-   nomenclature for the description of geologic map units (lithology,
    stratigraphy, geomorphology, pedology, petrology, genesis, etc.)

-   nomenclature for the description of linear geologic features
    (contacts, faults, fold axial traces, mapped marker units,
    geomorphic features, etc.),

-   nomenclature for the description of point geologic features
    (structural points, etc.);

-   nomenclature for descriptive and interpretive information about
    spatial and geologic relations among geologic map units, linear
    features, and point features (e.g., sequencing relations,
    stratigraphic relations, and geometric relations, etc.).

The standardized terminology will support a proposed standard
geologic-map data model for North America.

[Charge]{.underline}.---To achieve its mandate, the Science Language
Technical Team is charged with the following tasks:

\(1\) To determine the scope and comprehensiveness appropriate to a
continent-wide terminology for geologic map databases. Terminology scope
should reflect several realities, including (1) the intended use of the
geologic-map terminology, (2) the geologic scale to which the
terminology will be applied, (3) the prerogatives of historic usage by
various geologic-mapping constituencies, and (4) the degree to which
geologic terminology is amenable to a single hierarchical classification
structure. These factors (and others developed by the SLTT) should
determine the degree and level of standardization appropriate for
continent-wide geoscience language.

\(2\) To develop one or more strawman classifications for geologic-map
science language that will be made available for widespread peer review.

\(3\) To prepare and publish documents describing the basis for the
science-language terminology, and presenting the classification
scheme(s) and their technical and non-technical definitions.

[Authority]{.underline}.---The SLTT derives its authority and legitimacy
from the DMSC, which provides guidance and requirements on behalf of the
constituencies it represents.

[Accountability]{.underline}.---The SLTT is accountable to the DMSC.
Through a representative mutually acceptable to the SLTT and DMSC, the
SLTT periodically apprises the Steering Committee of progress toward
science language terminology and about issues and problems that need
consideration by the DMSC.

TECHNICAL-TEAM OPERATIONS

[Execution of work]{.underline}.---The SLTT will convene an initial
meeting to evaluate goals and to discuss issues, problems, and
terminology strategies. The Technical Team should have as many
face-to-face meetings as required to allocate responsibilities and to
resolve issues and problems not easily resolvable via e-mail.

[Lateral Coordination]{.underline}.---The SLTT will regularly
communicate strategies and proposed terminologies laterally to other
Technical Teams---especially the Data-Model Design Technical Team---in
order to ensure that data-model architecture and software tools
consistently reflect the evolving science language and concepts.

[Technical Review]{.underline}.---Science-language documents prepared by
the SLTT will be presented to the DMSC for initial review and evaluation
for compliance with the overall goals of the North American geologic-map
data model. Following DMSC review and SLTT response, the
science-language documents will be widely distributed for technical peer
review by the geosciences community (probably through a web-based
venue).

TECHNICAL-TEAM MEMBERSHIP

[Work Group Size]{.underline}.---The size of the SLTT should be
commensurate with its mandate: If geologic and political realities
require that the scope and content of data-model science language be
generalized and narrow, then the size of the Technical Team should be
small; however, if the scope and content of data model science language
is to be comprehensive and detailed, then the size of the Technical Team
should be large enough to ensure scientific comprehensiveness and
consensus of the larger geologic community.

[Scientific Breadth]{.underline}.---SLTT membership should span the
range of surficial and bedrock geologic disciplines, including expertise
in sedimentary, igneous, metamorphic, structural, stratigraphic, and
geomorphic/pedogenic arenas. Experts on specific scientific disciplines
can be added for short durations to address specific geologic issues
that arise during SLTT deliberations.

[Geographic Breadth]{.underline}.---SLTT membership should include a
broad range of geographic representation so as to reflect provincial
geologic usages.

[Constituency Breadth]{.underline}.---SLTT membership should represent
the constituencies that will contribute to geologic map
databases---initially including the U.S. Geological Survey (USGS), the
Association of American State Geologists (AASG), the Geological Survey
of Canada (GSC), and the Canadian Provincial Surveys. Inclusion of
industry and academic participants will depend on the narrowness or
breadth of the science-language standards.

[Appointment procedure]{.underline}.---SLTT members shall be appointed
by the DMSC based on the recommendations of each constituency and
considering the criteria defined in Scientific, Geographic, and
Constituency Breadth:

-   AASG recommendations will come from the AASG Digital Geologic
    Mapping Committee;

-   GSC recommendations will come from that agency as appropriate to its
    internal selection procedures;

-   Recommendations from the Canadian Provincial Surveys will come from
    those agencies consistent with their interest and appropriate to
    their internal selection procedures;

-   Recommendations from the USGS will come from that agency as
    appropriate to its internal selection procedures.

[Lifespan of Technical Team]{.underline}.---Continued existence of the
SLTT as a standing committee responding to data-model science--language
needs shall be at the discretion of the DMSC. The SLTT will remain
intact during the review period, and shall respond to Steering Committee
review and to peer review until such time as version 1.0 of the
science-language classification is adopted for use in the draft standard
data model.

**MILESTONES**

Within a year of convening its first session, the SLTT shall carry out
its charge to produce one or more science-language strawman
classifications. The SLTT receives guidance on milestones from the DMSC,
evaluates their feasibility, and reaches targets in conjunction with
DMSC.

# Appendix 2

Memorandum from SLTT Chair (Matti) to SLTT committee members (4/03/2000)

Participants on the Science Language Technical Team For a Proposed North
American Geologic-Map Data Model 04/03/2000

Science Language Technical Team colleagues:

By now, each of you hopefully is aware that you have been selected as a
participant on a technical team (Science Language Technical Team, SLTT)
tasked with coming to groups with how (or whether) a common set of
geoscience terms can be developed for digital geologic-map data bases
produced in North America. The SLTT is one of several parallel teams
commissioned on behalf of a proposed North American Geologic-Map Data
Model.

[Background]{.underline}

A standardized data-base model for the input, storage, manipulation,
retrieval, and analysis of digital geologic-map information is being
developed by a consortium of interests, including the Association of
American State Geologists (AASG), the U.S. Geological Survey (USGS), the
Geological Survey of Canada (GSC), and the Canadian Provincial Surveys.
The data model currently being evaluated was developed as a cooperative
venture by the USGS, the GSC, and the AASG.

This model attained visibility through a series of workshops and through
presentations at national GSA meetings. It developed as a likely
candidate for a North American data-model standard, and over a period of
time was revised and refined under the aegis of the AASG, the USGS, and
the GSC. The data model can be found on the World Wide Web at
<http://geology.usgs.gov/dm/model/Model43a.pdf> (version 4.3, Johnson
and others, 1999). Continued development of a data-model standard is
proceeding under the auspices of a multi-constituency North American
Data Model Steering Committee (NADMSC,
<http://geology.usgs.gov/dm/steering/>), which has commissioned the
technical teams that are developing various aspects of the data model.

[How did you come to be a participant in this process]{.underline}?

Scientists from the American state geological surveys were identified by
the Association of American State Geologists. Participants from the USGS
were nominated through a process that was coordinated through the three
Regional Geologists and through the Geologic Division Program
Coordinators. The two Canadian participants represent the Provincial
surveys and the Geological Survey of Canada; hopefully, additional
Canadian participants will be identified in the near future. I am in the
process of recruiting a few representatives from the geologic-map using
community within the U.S. Departments of Interior and Agriculture, one
of whom has been identified. All of you are viewed as ideal for
responding to the task before us.

[Where is the SLTT process now, and what is next]{.underline}?

It has taken a while to establish the SLTT membership because it has not
been easy to coordinate among multiple constituencies. But, we are about
there, so I thought I would bring you up to speed, and address some
mechanical issues.

\(1\) I want to start business on April the 17^th^.

\(2\) We have a year from that date to execute our responsibilities.

\(3\) I imagine a month of your time will be required throughout the
12-month cycle, but time invested will depend on interest level and
commitment to the SLTT process.

\(4\) As a Team, we will work together to develop interim milestones.

\(5\) We will regularly keep the Data Model Steering Committee appraised
of our progress.

\(6\) Our initial dialogue will be electronic, in the form of email and
a web-conference site devoted to science-language issues
(<http://geology.usgs.gov/dm/terms/>).

\(7\) Please access the web-conference site and register. The site was
constructed and is maintained by Peter Schweitzer of the USGS, who
assures me that it will work as advertised (all who register at the site
are supposed to be notified by email when a new contribution is made,
but if anything can go wrong, it must go wrong!).

\(8\) My role is that of a facilitator. My job is to stimulate *your*
creativity and *your* analytical approach to our task. If I am not doing
that, I am failing and you must so inform me.

\(9\) Attached to this mail are several .pdf files, one being an
archival copy of this email. My hunch is that .pdf exchange will be a
common tool for the SLTT's business, so if you do not have a .pdf reader
or if somehow my files are not readable by you, we need to find a fix.
Please advise.

\(10\) The attached files include the SLTT charter, a roster of SLTT
participants, and a guidelines document that the Data Model Steering
Committee has reviewed, revised, and endorsed. The guidelines set the
philosophy and tone of how the SLTT should go about its business. We
will not be scrutinized by the DMSC, but we do have a specific mission
that body expects us to achieve.

\(11\) I encourage you to reach out to colleagues in your organization
to discuss science-language issues. We represent our colleagues and
speak for them---not in place of them.

\(12\) Travel and travel costs: Yes, there will be a face-to-face
meeting among us. As a Team, and in conjunction with the DMSC, we will
have to work out the mechanics of a face-to-face, and how (or if) funds
can be identified to defray (not subsidize) travel costs. I think a
face-to-face is essential, for it will unite us in our task and because
inter-personal exchange of ideas is always better than the impersonal
electronic forum. However, travel has its costs (time and money), and
such costs cannot be treated in cavalier fashion. We will discuss this
as we go along.

\(13\) Finally, if you have searched your gut and truly do not want to
participate in the SLTT process, or have second thoughts owing to the
press of other obligations, please inform me as soon as possible. I will
wish you well and find a replacement for you. It is essential that we
all feel good about this process, and truly want to be a part of it.

I will be on the road for most of this week, and not able to check my
email for much of that time. Please use this period before 17 April to
get yourself into the swing of things regarding geologic-map standards.
I will be back in contact next week with more mechanical issues.

In the meantime, here is our first task:

In order to set the tone for our task and see how each of us views the
information content of a geologic map, please come up with 20 data-base
queries that you personally would want to launch at a digital
geologic-map data base. We can exchange these query-lists by email, and
post them at the web-conference site. Use the following syntax:

\(1\) show me all metasedimentary rocks;

\(2\) show me Paleozoic and Late Proterozoic metasedimentary rocks
intruded by Cretaceous 2-mica monzogranite;

\(3\) show me all low-angle faults, irrespective of their extensional or
contractional origin;

\(4\) show me all rock units affected by two generations of folding;

\(5\) show me all slope-failure deposits;

\(6\) show me all slope-failure deposits of slump-block and earth-flow
origin;

\(7\) show me all surficial deposits with well-developed Bt soil
horizons.

I will come through with my 20, but this quick sample represents just a
smattering of topics and issues that I would need to retrieve from a
typical geologic-map data base in southern California. Good luck, and
have fun.

Personally, I am looking forward to working with all of you.
Collectively, we represent a considerable body of common sense,
scientific breadth, and geologic-map experience (either on the
data-production side or the data-use side). With such a mix, I am
confident that we will do justice to the notion of common standards for
geologic-map terminology---or, if such standards can not be developed
and adopted, then at least a good set of minds will have reached that
conclusion.

Adios from Tucson, Jonathan

# Appendix 3

Memorandum from SLTT Chair (Matti) to SLTT committee members (4/03/2000)

SCIENCE-LANGUAGE TECHNICAL TEAM

Guidance from the North American data-model Steering Committee

04/03/2000

MANDATE

The Science Language Technical Team (SLTT) is mandated to develop
standardized nomenclature for digital geologic-map data bases, including
(but not limited to) the following areas:

(1) nomenclature for the description and characterization of
    geologic-map units (lithology, stratigraphy, geomorphology,
    pedology, petrology, genesis, etc.)

(2) nomenclature for the description and characterization of linear
    geologic features (contacts, faults, fold axial traces, mapped
    marker units, geomorphic features, etc.),

(3) nomenclature for the description and characterization of point
    geologic features (structural points, etc.);

(4) nomenclature for descriptive and interpretive information about
    spatial and geologic relations among geologic map units, linear
    features, and point features (e.g., sequencing relations,
    stratigraphic relations, and geometric relations, etc.).

GUIDING PRINCIPLES

(1) The SLTT's focus is digital geologic-map data bases---NOT geologic
    maps. Geologic maps as cartographic products should be viewed by the
    SLTT as derivative output FROM the data bases, not as mainline
    products supported BY the data bases;

(2) The SLTT's focus is the geoscience content of geologic-map data
    bases---not data-base design. SLTT recommendations and decisions
    regarding geoscience concepts and their attendant vocabulary and
    inter-relations will be passed upward to the Steering Committee and
    laterally to the Data-model Design Technical Team for evaluation and
    incorporation into data-model modification and tool development;

(3) Geoscience classification and nomenclature scheme(s) should be
    scale-independent;

(4) Classification and nomenclature scheme(s) should allow the data-base
    author to describe and interpret geologic elements as richly or
    poorly as the data allow---even within a single data base. To
    support this functionality, nomenclatural items should be related
    hierarchically in a way that allows geologic materials and geologic
    structures to be described and interpreted in progressively more
    detail and richness while still allowing them to be grouped into
    progressively broader categories;

(5) Classification and nomenclatural scheme(s) should be robust enough
    to provide stability and consistency of usage, but flexible enough
    to accommodate differences owing to regional or institutional
    mapping traditions or mission requirements;

(6) Classification and nomenclatural scheme(s) should allow the data
    bases to be queried for standardized geoscience concepts and
    geoscience attributes---ranging from the mundane to the
    sophisticated. Data-base queries can be only as successful as the
    architecture and language of the geologic data base that is queried;

(7) Classification and nomenclatural scheme(s) should accommodate all
    audiences and data-base users---from the educated lay audience
    through the end-user in local through Federal agencies, culminating
    in the technical geoscience user in academic and institutional
    audiences;

(8) Classification and nomenclatural scheme(s) should integrate
    seamlessly with a broad range of interdisciplinary data
    bases---including (but not limited to) engineering, geophysical,
    geochemical, hydrologic, environmental, and geographic data bases
    and interactive applications.

# Appendix 4

Memorandum from SLTT Chair (Matti) to SLTT committee members
(12/01/2000)

Science Language Technical Team

Action Plan

1 December, 2000

SLTT colleagues:

About 15 of us got together the morning of 13 November \[at Geological
Society of America Annul Meeting, Reno, Nevada, 2000\] to discuss
general issues and to develop an action plan for our science-language
activities. This document summarizes the discussions, and provides the
guidance for our activities over the next few months.

**Participants**

> Lucy Edwards (USGS)
>
> Bruce Johnson (USGS)
>
> Ron Kistler (USGS)
>
> Alison Klingbyle (GSC)
>
> Diane Lane (USGS)
>
> Steve Ludington (USGS)
>
> Jim MacDonald (Ohio Geological Survey)
>
> Jon Matti (USGS)
>
> David Miller (USGS)
>
> Steve Richard (Arizona Geological Survey)
>
> Peter Schweitzer (USGS)
>
> Loudon Stanford (Idaho Geological Survey)
>
> Andy Rorick (U.S. Forest Service)
>
> Richard Watson (U.S. Bureau of Land Management)
>
> Jerry Weisenfluh (Kentucky Geological Survey)

\(1\) What we need to do

-   develop lists of **control-words** for the description and naming of
    geologic materials and geologic structures. Control-words are
    rigidly defined words whose definitions cannot be violated
    (sandstone has exactly one definition; monzogranite has exactly one
    definition; thick-bedded has only one definition);

-   provide formal definition of each control-word (sources: AGI
    dictionary of geoscience, IUGS plutonic-rock classification,
    widely-cited geoscience textbooks, etc.)

-   develop hierarchical classification of control-words (parent-child
    relationships using software to be announced) (e.g., Visio2000pro)

-   provide all documentation by 30 April, 2001, including:

    1.  definitions of control-terms

    2.  diagrams of parent-child relations

    3.  Minimal boiler-plate that describes our results and places them
        in the context of the proposed North American geologic-map data
        model

-   Consider developing a thesaurus approach to control-terms and their
    non-controlled equivalents (synonyms, related terms, proxies for
    control-terms)

\(2\) Specific components of 1.0 strawman

-   For the following categories, develop control-terms for the deepest
    level possible in each hierarchy:

    1.  **rock name** (e.g., limestone, monzogranite, blueschist,
        colluvium)

    2.  **lithologic attribute** (e.g., coarse-grained,
        fissil-weathering, thin-bedded, unconsolidated, texturally
        massive, porphyritic, porphyroclastic, mullion)

    3.  **rock genesis** (e.g., marine, nonmarine, alluvial, plutonic,
        volcanic, fluvial, colluvial, dynamothermal, high-strain)

    4.  **genetic structures** (e.g., flow foliation, eutaxitic fabric,
        cumulate layering, graded bedding, sole structures, slaty
        cleavage, earth flow, )

        -   If possible, develop as part of each hierarchy generic field
            terms that allow for general-purpose classification of
            materials and structures (e.g., "granitic", "basaltic",
            "conglomeratic", "marble", "mudrock", "cross-bedded",
            "gneissic" "mylonitic", "silty") so that reconnaissance
            observations can be recorded meaningfully in the data model

        -   Identify internationally-recognized geologic-time
            classifications that can be used by the data model. The SLTT
            does not have to recommend or advocate any one scheme: we
            merely have to collect them together as schemes that can be
            used by the data producer. The data model design team will
            develop a metadata technique for associating an age term
            with its time-scale scheme. Time scales that come to mind
            include:

            A.  Harland and others (1989)

            B.  IUGS timescale (Remane, 2000)

            C.  time scales compiled in Berggren and others (1995)

**(3) Target Audience:** Science language should be technical---that is,
it should be developed by and speak to the trained geologist. Although
we all are concerned about how the professional and non-professional
non-geoscience audience will access and understand our database content,
this concern should be addressed by a technical team tasked with
designing the data-model user interface.

**(4) Basis and scale of terminology:** Map-unit categories (i.e.,
formation, member, tongue, lentil, bed) are conceived and extended
through a process that integrates hierarchical observations beginning at
the ***hand-sample and outcrop level*** but extending to the ***hillside
and regional level*** and augmented by the ***thin-section and
chemical-analysis*** level. Thus, hierarchical terminology schemes
leading to map-unit description should reflect:

-   regional-scale observation

-   hillside-scale observation

-   outcrop-scale observation

-   hand-sample-scale observation

-   thin-section-scale observation

-   chemical analysis-scale observation

\(5\) Existing strawman-classifications for consideration include (but
are not limited to):

-   Rock classification schemes of British Geological Survey (BGS)

-   Version 6.0 classification scheme of SLTT member Bruce Johnson
    (Matti will distribute again; Johnson will provide parent-child
    diagrams)

-   Volcanic and plutonic classification schemes of SLTT member Steve
    Ludington (Matti will distribute again)

-   SCAMP version 2.0 rock-classification schemes (Matti will distribute
    again)

-   Any other hierarchical classification schemes that subgroup members
    can identify

\(6\) In addition to nomenclature for sedimentary, igneous, metamorphic,
and surficial materials, we need to develop language for the following
materials:

-   tectonic rock units (e.g., broken formations, mélanges, tectonic
    breccia, bolide-impact rocks)

-   rock-types of hydrothermal or alteration origin

-   rock-types of mixed origin

-   rock-types of unknown origin

\(7\) The following rules MUST be adhered to:

-   hierarchies must follow independent non-intersecting pathways (or so
    I understand \[correctly?\] from the data model design people)

-   A control-term cannot be arrived at by more than one pathway. For
    example, the mineral "calcite" cannot be arrived at via a
    sedimentary pathway leading to calcite or a metamorphic pathway
    leading to calcite or an igneous pathway leading to calcite.
    Instead, the mineral calcite must be approached via a single pathway
    in a mineralogy hierarchy that incorporates children of calcite
    (e.g., calcite, *sedimentary*; calcite, *metamorphic*; calcite,
    *vein*)

\(8\) To assist data-model design team, we need to distinguish between
the following terms:

-   "rock"

-   "rock unit"

-   "map unit"

\(9\) To assist data-model design team in developing a map-unit
characterization field

-   develop language that allows each map unit to be characterized
    concisely and distinguished clearly from other map units

-   develop control terms applicable to lower, upper, and lateral
    **boundaries of map units** (e.g., conformable, unconformable,
    sharp, discrete, transitional, gradational, mixed, migmatitic,
    intrusive, extrusive, interfingering) and for distinguishing
    properties (geologic, geomorphic, pedogenic, paleontologic. This may
    not be possible within the scope of our initial lithologic
    assignment, but we need to have it on our radar screen as we do our
    job, and make some progress in this direction.

References Cited

> Berggren, W.A., Kent, D.V., Aubry, M-P., and Hardenbol, J., eds.,
> 1995, Geochronology, time scales and global stratigraphic correlation:
> Tulsa, Oklahoma, Society of Economic Paleontologists and
> Mineralogists, Special Publication 54, 386 p.
>
> Harland, B.W., Armstrong, R.L., Cox, A.V., Craig, L.E., Smith. A.G.,
> and Smith, D.G., 1989, A geologic time scale, 1989: New York,
> Cambridge University Press, 246 p.
>
> Remane, Jurgen, compiler, 2000, International Stratigraphic Chart:
> Division of Earth Sciences, UNESCO, 16 p., 1 plate. Published in
> cooperation with the International Union of Geological Sciences and
> the International Commission on Stratigraphy.

# Appendix 5

Memorandum from SLTT Chair (Matti) to SLTT Sedimentary and Surficial
subgroup members (2/15/2001)

Sedimentary and Surficial Subgroup Colleagues: 02/15/2001

Now that the surficial and sedimentary SLTT teams both have launched
their deliberations, we need to address an issue of concern to both
teams.

Several members of the sedimentary group have indicated concern about
possible overlap between "unconsolidated" sediment and unconsolidated
surficial materials. This concern originates from the British Geological
Survey's (BGS) classification of sedimentary materials into "lithified"
and "unlithified" materials:

\"The primary classification of sediments and sedimentary rocks is based
on their compositional attributes present at the time of deposition.
This allows sediments to be classified by the same compositional
boundaries as sedimentary rocks.\"

The following points address this issue, and seek to clarify the unique
assignments of the surficial-materials team and the sedimentary team. As
you see fit, please comment on any of the points

(1) I do not think the BGS blurs the boundaries between their
    "unlithified sediment" and "unconsolidated surficial materials";

(2) The BGS scheme simply provides names for unlithified sediment that
    are parallel with the names for lithified sedimentary rock;

(3) The surficial team is charged with developing a classification of
    surficial materials like "alluvium", "colluvium", "landslides", and
    so forth. I suspect that the group will come up with classification
    categories such as "alluvial deposits", "colluvial deposits",
    "landslide deposits", etc., all representative of surficial
    materials that are relatively "unlithified";

(4) These surficial materials will have certain physical properties
    (such as grain size, particle shape, bedding thickness, grain
    composition, grain-matrix ratios, color, etc.) that will overlap
    with the physical properties of sedimentary materials, both
    lithified and unlithified. This overlap will be especially obvious
    between surficial materials that are water-laid and unlithified
    sediment that is water-laid: the two are one and the same, are they
    not? And that is the source of the apparent overlap;

(5) Should both the surficial team and the sedimentary team
    independently create classification schemes for (a) unlithified sand
    bodies that form bars on the Platte braided-river plain or (b)
    unlithified sand bodies in coastal chenier plains or (c) unlithified
    oolitic shoals in the Bahamas or (d) unlithified mudrock and
    channelized sand bodies in the Mississippi River delta?

(6) My answer to question (5) is "no". I expect that the surficial team
    will view those specific examples as surficial materials that could
    be classified and named and mapped as (a) alluvium, braid-plain type
    or (b) paralic deposits, chenier-plain type or (c) marine surficial
    deposits, carbonate, oolitic-shoal type or (d) alluvial deposits,
    deltaic (to name some hypothetical possibilities);

(7) I believe that the physical properties of unlithified deposits and
    the *naming of specific sediment types they contain*, are the
    purview of the sedimentary team. This is the position the BGS takes,
    I believe;

(8) Thus, for points (5) and (6): (a) alluvium, braid-plain type, may
    consist of medium-bedded, texturally massive to flat-laminated,
    moderately sorted, medium- to coarse-grained quartzofeldspathic
    lithic sand, while (b) paralic deposits may consist of crudely
    bedded flat-laminated to trough-laminated, well-sorted, fine- to
    medium-grained quartz arenite sand while (c) marine surficial
    deposits, carbonate, oolitic-shoal type may consist of\...\....etc.;

(9) I think the tasks of the two teams will be clarified if we adopt the
    following:

-   the surficial team is classifying deposit types that can be used as
    map units, and that also may occur within map units, but are not
    specific lithologies or petrographic sediment names

-   the sedimentary team is classifying rock types that occur as
    specific lithologies in outcrops and in map units

-   the sedimentary team will develop much of the classification and
    description nomenclature for specific rock types, but they must do
    so in partnership with the surficial team so that cross-pollination
    occurs

(10) The distinction between "consolidated" and "unconsolidated" or
     between "lithified" and "unlithified" is going to be a vexing
     issue, irrespective of the issues raised in the preceding nine
     points. I will not venture into this now.

Please ruminate over the ideas in this note. If we are not on the same
page on this one, we could get into trouble. I am just thinking out
loud, so give it your own treatment.

Adios, Jonathan

# Appendix 6

Memorandum from SLTT Chair (Matti) to SLTT committee members (3/14/2001)

SLTT colleagues: 03/14/2001

Recent discussion within some of the subgroups indicates the need to
restate and clarify the purpose of our SLTT goals and the nature of our
classification activities. Please read this memo carefully and at your
earliest convenience. If any of you has major reservations, concerns, or
disagreements about these objectives, please raise them to all of us
now.

By separate mailing, I am sending a copy of this memo to the North
American Data Model Steering Committee, whose members also are asked to
comment and evaluate the statements.

(1) [Databases versus geologic-maps]{.underline}: *Our purpose is to
    develop classification structures for digital geologic-map
    databases*, not for digital versions of geologic maps*.* The
    production of a geologic-map plot is incidental to the database, and
    is not the primary focus of the language that the SLTT is
    developing.

> The difference in tone here is important: the hierarchical structure,
> number of rock classes, and other aspects of our language schema
> should be tailored to storing and searching science concepts in a
> digital database, not tailored to the requirements of database fields
> in a particular data model or tailored to the text in a geologic-map
> legend.

(2) [Language for new data *versus* language for
    compilation]{.underline}: While the compilation of pre-existing
    geologic mapping obviously is part of a geologist's activities, the
    SLTT's primary driver is to develop schema that *facilitate the
    classification and communication of new field information*. We must
    look into the future toward novel ways of organizing new data, not
    into the past to find ways of facilitating the compilation of old
    data. The former will benefit the latter in obvious ways.

> Map compilation (the collation, evaluation, interpretation, and
> translation of geologic-map information contained in products produced
> by other workers) is a necessary and legitimate goal. However, the
> creation of science language that supports geologic-map compilation is
> not the SLTT purpose.

(3) [Do we need to accommodate pre-existing science
    language?]{.underline}: Compilation of pre-existing geologic-map
    information requires the geologist to deal with a wide array of
    lithologic names and descriptors that have come down through the
    generations. Should the SLTT classification schema create a place
    for these terms, or define equivalencies for them?

> No. *Our task is to create a single uniform, coherent classification
> that logically, objectively, and thoughtfully establishes rock names
> and descriptors that classify geologic materials accurately and
> comprehensively according to modern usage*. We are not obliged to
> create a list of synonyms or equivalencies. We are not necessarily
> required to make a place for previous usage, no matter how entrenched
> that usage might be.
>
> For the compilation of pre-existing map information, it is (and always
> should be) the responsibility of the map compiler to interpret what a
> published geologic map contains, and to place this information in the
> context of modern rock classifications. This is why geologists (who
> have the training and expertise to make geologic judgments) should be
> map compilers. The SLTT classification schema will be *the* modern
> standard for geologic-map database attributes. *It will be the
> responsibility of future map compilers to interpret the nomenclature
> of pre-existing geologic-map information for its position in the SLTT
> schema, not the responsibility of the SLTT to accommodate all previous
> language.* Pre-existing language should be treated either in
> feature-level metadata or dataset metadata: this will create a paper
> trail for original usage, but will not burden the SLTT schema with the
> diverse nomenclature of the past.

(4) [Language for data producer *versus* end user]{.underline}: *The
    lithologic classification schema we are developing are NOT for the
    end user, but for the geologist who is collecting attribute data and
    populating a database with the attributes*. The production of
    derivative databases and map plots that serve end users is not the
    SLTT concern.

> Does this mean that the SLTT is not mindful of end-users? Nope. Each
> of the four subgroups is working hard to develop science language that
> will form a foundation for users of all kinds---from technical to
> non-technical. But the SLTT focus needs to be geologist-directed in
> order for the multiple-user base to be served.
>
> We all are interested in and concerned about how end users access and
> use geologic-map information. However, I strongly believe that the
> proper focus of end-user facilitation should be the design of an
> appropriate user-interface. It will be the job of (a) the SLTT, (b)
> the data-model design team, and (c) a user-interface team (currently
> not designated) to design an appropriate tool-set to take the concepts
> and language designed by the SLTT and make them user-friendly.

(5) [Hand-sample language *versus* map-unit language]{.underline}: *The
    SLTT mandate is to provide classification schema for individual rock
    types that occur in geologic-map units, together with language that
    describes the physical appearance, composition, and genesis of these
    rock types*. The science language must focus on hand-sample and
    outcrop-scale attributes, but should include rock names and fabric
    relations that derive from thin-section observations as well as
    language for sequencing and stratigraphic relations at the map-unit
    scale.

(6) [How comprehensive or finite should our classification schema
    be]{.underline}? *Our science language should reflect the realities
    of geology, not the requirements of end users*. However, the
    geologic universe is complex, so should the classification schema be
    complex and opaque? Nope. And that is the challenge: to represent
    rock names and rock structures within families that bring order to
    the complexity.

> In a note to the metamorphic subgroup, Bruce Johnson correctly pointed
> out that " if the classification is hierarchical, and the first and
> second levels of the hierarchy are limited to a small number of
> classes, then it becomes possible to render the map by ignoring lower
> levels". Bruce's concern here is that the plethora of detail that we
> could create in our classification schema should not bar the database
> user from perceiving the major high-level relationships among geologic
> elements. I agree completely. However, if logically structured, then
> the number of classes or branches or levels of the hierarchy will not
> matter.
>
> In my opinion, the user interface will be THE critical device for
> sorting through the database from higher (general) levels to lower
> (detailed) levels to accommodate user needs.

(7) [Do we need flow charts and glossaries]{.underline}?: To the extent
    that we must define control terms and root names, etc., then to that
    extent we are defining a glossary of terms. One strength of the
    British Geological Survey Rock Classification schemes is the
    decision-making pathways (flowcharts) that the schemes establish for
    the use of data producer and data-compiler (and ultimately, from an
    interface point of view, the data user). A decision-support
    mechanism is a natural fallout of control terms: the terms must have
    definitions, and a decision process must be executed in order for a
    control term to be used or not used by the geologist and end-user. A
    flow chart is a logical device for displaying the decision-support
    process.

Let me end by sharing what I am discovering while working with the
sedimentary subgroup. In my opinion, we need hierarchical classification
schema that allow the geologist to go as deep into the data-attribution
process as possible---without getting painted into a corner. The BGS
sedimentary classification scheme doesn't have a lot of wiggle room in
it. For example, feldspar-rich sedimentary rocks are termed "feldspathic
arenites" as defined by Pettijohn. End of statement. End of choices. I
personally would be more comfortable if an intermediate level existed
that gave the geologist (and the end user) more generic terms like
"feldspar-rich" or "lithic-rich", *before* requiring the geologist (and
the end user) to commit to the name "feldspathic arenite". This would
allow me to classify a rock in the field as a "feldspar-rich sandstone"
based on hand-lens observation, and I could stick with this name if I
never obtained modal data that would allow me to document the rock as a
feldspathic arenite (*sensu* Pettijohn). My audience can get a lot out
of the term "feldspar-rich sandstone", even though I haven't tagged the
rock as a "feldspathic arenite" *sensu strictu*.

In other words, common sense needs to drive our process---and I ask that
you work with each other to find this common sense. A purely academic
approach to rock classification and description is not going to do us
any good. Even though I minimized the role of the end-user as a target
for our deliberations, none-the-less both the field geologist and the
land-use manager need a classification that allows each to (a) classify
a rock in as much detail as desirable and (b) search the forest before
searching out individual trees.

In other words, we do not have an easy job.

Adios, Jonathan

[^1]: *standard*---"*n*. **1**. Something considered by an authority or
    by general consent as a basis of comparison. **3**. a rule or
    principle that is used as a basis for judgment: *they tried to
    establish standards for a new philosophical approach*.

    ---*adj*. **23.** serving as a basis of weight, measure, value,
    comparison, or judgment. **24**. of recognized excellence or
    established authority. **25.** usual, common, or customary:\..."
    (Webster\'s Encyclopedic Unabridged Dictionary of the English
    Language, 2001, p. 1857).

[^2]: N[]{#footnote_2 .anchor}OTE: Legacy terminology absolutely must be
    preserved in modern geologic-map databases. The question is not
    whether such language is *preserved* (for example, in a
    "legacy_description" data field), but whether it is *integrated*
    into the dynamic structure of the database so that it can be easily
    and systematically queried for its science content.

[^3]: This is similar to the DMDT definition of *earth material*: "the
    substance of the solid Earth (rocks, minerals, organic material,
    glass, void space), defined based on intrinsic properties
    independent of their disposition within the Earth" (North American
    Data Model Steering Committee, 2004d).

[^4]: As translated by Bowles (1984, p. 151-152), relative density is an
    engineering parameter that relates void space determined in the
    laboratory to a ratio involving index values of minimum and maximum
    void space for specified materials under specified conditions. Void
    space in turn is related to *in situ* dry unit weight. Also see the
    *Glossary of Geology* definition of relative density (Jackson, 1997,
    p. 540).