U.S. GEOLOGICAL SURVEY DIGITAL DATA SERIES DDS-46

Geology and Resource Assessment of the Venezuelan Guayana Shield at

1:500,000 scale\--A Digital Representation of Maps published by the U.S.

Geological Survey

By Paul G. Schruben(1), Jeffrey C. Wynn(1), Floyd Gray(2), Dennis P.
Cox(3),

John H. Stewart(3), and William E. Brooks(3)

\(1\) U.S. Geological Survey

920 National Center

12201 Sunrise Valley Drive

Reston, VA 22092-9998

\(2\) U.S. Geological Survey

210 E. 7th St

Tucson, AZ 85705-8454

\(3\) Formerly with U.S. Geological Survey

U.S. DEPARTMENT OF THE INTERIOR

BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY

Gordon P. Eaton, Director

For sale by U.S. Geological Survey, Map Distribution

Box 25286, Building 810, Federal Center

Denver, CO 80225

Prepared in the Eastern Region, Reston, Va.

Manuscript approved for publication .

1997

TABLE OF CONTENTS

Title Page

Disclaimer

System Requirements

Acknowledgments

Contacts

Disc Contents

Project Overview

History of the Maps

Bulletin 2062 Text and Figures Files

References for this Disc

Digital Production Techniques

Map Projection

Cautions Relating to the Use of the Maps

Online Files

Graphics Formats Available on the Disc

ARCVIEW 1 and ARC/INFO Files

Export Files

Raw UNIX Coverages

PC ARCVIEW 1 Coverages

Running the Plot Programs

Installing ARCVIEW 1

Using ARCVIEW 1

ARCVIEW 1 Files

ARCVIEW 3 Files

Coverage Data Definition

DLG Optional Format

Descripton of Map Units

DISCLAIMER

This Compact Disc-Read Only Memory (CD-ROM) publication was prepared by
an agency of the United States Government. Neither the United States
Government nor any agency thereof, nor any of their employees, makes any
warranty, expressed or implied, or assumes any legal liability or
responsibility for the accuracy, completeness, or usefulness of any
information, apparatus, product, or process disclosed in this report, or
represents that its use would not infringe privately owned rights.
Reference therein to any specific commercial product, process, or
service by trade name, trademark, manufacturer, or otherwise does not
necessarily constitute or imply its endorsement, recommendation, or
favoring by the United States Government or any agency thereof. Any
views and opinions of authors expressed herein do not necessarily state
or reflect those of the United States Government or any agency thereof.

Although all data and software published on this CD-ROM have been used
by the USGS, no warranty, expressed or implied, is made by the U.S.
Geological Survey as to the accuracy of the data and related materials
and/or the functioning of the software. The act of distribution shall
not constitute any such warranty, and no responsibility is assumed by
the USGS in the use of these data, software, or related materials.

Graphical map depictions on this disc are intended to be used within the
map scale limits applicable to the source data. Although software
enables the user to show images on the disc at various scales, the user
is cautioned to refer to the source documentation for the appropriate
map scale limitations.

SYSTEM REQUIREMENTS

This CD-ROM was produced in accordance with the ISO 9660 standard and
thus allows access to the disc files by computers with ISO 9660 software
drivers. The disc contains Adobe Acrobat Reader software for DOS,
Macintosh, UNIX, and Windows. as well as a graphics display program,
ArcView 1, for Windows 3.x.

ARCVIEW 1 REQUIREMENTS

80386 or better CPU

Math coprocessor recommended

Windows 3.0 or higher but not Windows 95

4 Mb of RAM, 8 Mb strongly recommended

15 Mb of disk space

Super VGA graphics system, 256 colors, 640x480 pixels minimum,

1024x768 pixels strongly recommended

Microsoft-compatible mouse

Windows-supported printer

ARCVIEW 3 REQUIREMENTS

80486 or better CPU

Windows 3.x, 95, or NT

12-16 Mb of RAM

Super VGA graphics system, 256 colors, 640x480 pixels minimum,

1024x768 pixels strongly recommended

Microsoft-compatible mouse

or

Power Macintosh or 68040 processor with FPU

System 7.1 or higher

16-18 Mb of RAM

Adobe Acrobat Reader REQUIREMENTS:

A color display monitor is strongly recommended with all platforms.

Windows 95 - rs32e30.exe

Minimum

i386(TM), i486(TM), Pentium(R), or

Pentium Pro processor-based personal computer

Microsoft Windows 95, or Windows NT(R) 3.51 or later

8 MB of RAM (16 MB for Windows NT) for Acrobat Reader

10 MB of available hard-disk space

Recommended

Pentium processor-based personal computer

Windows 95 or Windows NT

16 MB of RAM (24 for Windows NT)

10 MB of available hard-disk space

Windows NT - rs32e30.exe

Minimum

i386(TM), i486(TM), Pentium(R), or Pentium Pro processor

Windows NT(R) 3.51 or later

8 MB of RAM (16 MB for Windows NT) for Acrobat Reader

10 MB of available hard-disk space

Recommended

Pentium processor-based personal

computer

Windows 95 or Windows NT

16 MB of RAM (24 for Windows NT)

10 MB of available hard-disk space

Windows 3.1 and 3.11 for Workgroups - rs16e30.exe

Minimum

i386(TM), i486(TM), Pentium(R), or Pentium Pro processor

Microsoft Windows 3.1 or Windows 3.11 or later

8 MB of RAM for Acrobat Reader

5 MB of available hard-disk space

Recommended

Pentium processor-based personal computer

Microsoft Windows 3.1 or Windows 3.11 or later

12 MB of available hard-disk space

Macintosh and Power Macintosh - Install Acrobat Reader 3.0, Search
Installer

Minimum

Macintosh with a 68020 or greater processor, or Power Macintosh

3.5 MB of RAM (5 MB for Power Macintosh) available to Acrobat Reader

Apple(R) System Software version 7.1 or later

Recommended

8 MB of available RAM

Apple System Software version 7.1.2 or later

12.5 MB of available hard-disk space

UNIX

UNIX system requirements

12 MB of disk space for Acrobat Reader

System with 32 MB of RAM

Sun SPARCstation(R) - acroread_sunos_30.tar.gz,
acroread_solaris_30.tar.gz

SunOS 4.1.3 or 4.1.4 or Solaris 2.3, 2.4, or 2.5

OpenWindows(TM) (version 3.0 or later),

Motif(TM) window manager (1.2.3 or later),

OpenLook version 3.0, or

Common Desktop Environment (CDE) 1.0 and above

HP Series 9000 workstation, model 700 or greater -
acroread_hpux_30.tar.gz

HP-UX 9.0.3 or later

X Window System(TM) X11R5 with HP-VUE or CDE 1.0

12 megabytes of available hard disk space

A 32 megabyte machine

IBM(R) RS/6000(TM) workstation - acroread_aix_30.tar.gz

AIX 4.1 or later operating system

Common Desktop Environment (CDE) or the Motif window manager

Silicon Graphics workstation - acroread_irix_30.tar.gz

IRIX(TM) 5.3 or later operating system software

12 megabytes of available hard disk space

A 32 megabyte machine

Linux workstation - acroread_linux_30.tar.gz

LINUX 5.3 or later operating system software

12 megabytes of available hard disk space

A 32 megabyte machine

OS/2 - aro2e30.exe

Minimum

i386, i486, Pentium, or Pentium Pro processor

IBM OS/2 Warp or Warp Connect 3.0 or later

4 MB application RAM available to Acrobat Reader

8 MB RAM for system

5 MB hard-disk space, plus 5 MB temporary space for installation

Recommended

Pentium processor

IBM OS/2 Warp 4.0

Adobe Acrobat Reader 1.0 for DOS - rdrdos10.zip

Minimum

i386(TM), i486(TM) processor

Microsoft DOS 3.3 or later

2 MB of RAM for Acrobat Reader.

5 MB of available hard-disk space

Recommended

486 or Pentium processor

Microsoft DOS 3.3 or later

4 MB of application RAM

5 MB of available hard-disk space

ACKNOWLEDGEMENTS

Development of the graphics files on this CD-ROM spanned many years and
involved the efforts of many organizations and individuals. Most of the
digitizing was done in GSMAP by Jeff Wynn (USGS) and others. The
northern quadrangles were scanned from tracings created by the
geologists. Thanks to the following authors for those materials:

John H. Stewart (USGS)

Dennis P. Cox (USGS)

Floyd Gray (USGS)

W. E. Brooks (USGS)

Thanks to Corporación Venezolana de Guayana, Técnica Minera C.A. and the
following authors of Venezuela maps and reports for their help in the
preparation of the digital files:

Juan Acosta

Jesús Arespón

Yasmin Estanga

Luis Franco

Andrés García

Yolanda Lopez

Elis Lugo

Iris Marcano

Félix Martínez

Vicente Mendoza-S.

Stephen D. Olmore

Inés Rendón

Haydée Rincón

Nelson Rivero

Edixon Salazar

Gary B. Sidder (formerly USGS, now Golden Star Resources)

Frank Tovar

Thanks to David K. Traudt, USGS, who assembled the files and directories
from tape to master CD-ROM. Thanks to the following personnel in the
USGS who provided disk files of Bulletin 2062 text and figures as well
as many thoughtful suggestions for improvements to the maps and text on
the CD-ROM.

Frederick C. Brunstein

David A. Emery

Will Stettner

Judith W. Stoeser

CONTACTS

Questions about the digital map files should be directed to:

Paul Schruben Telephone (703) 648-6142

FAX (703) 648-6383

E-mail pschrube@ usgs.gov

U.S. Geological Survey, 954 National Center, Reston, VA 22092-9998.

Technical help with ArcView 1 is available via CompuServe by typing GO
ESRI.

Copies of the original USGS 1993 Bulletin 2062, MF maps cited in the
Documentation of Map Units, and this CD-ROM are available from:

U.S. Geological Survey, Map Distribution

Box 25286, Building 810

Federal Center

Denver, CO 80225

Tel: (888) ASK-USGS or for overseas access (703) 648-6045.

DISC CONTENTS

1readme.doc description of this disc, Microsoft Word 6 file

1readme.mac.text description of this disc, Macintosh/OS plain text file

1readme.pdf description of this disc, Adobe Acrobat Reader file

1readmet.dos description of this disc, MS/DOS plain text file

1readmew.dos description of this disc, Microsoft Word for Windows 1.0

acrobat directory containing Acrobat Reader installer programs

arcview1 directory containing ArcView 1 installer program

arcpc directory containing PC ArcView 1 and ARC/INFO directories.

Same as arcunix6 directory below

arcunix6 directory containing ArcView 1 and ARC/INFO 6.1.2 directories

at directory containing files for Atabapo 2¡x3¡ quadrangle

(Venezuela part)

at.aml ARC/PLOT program for 44\" Versatec plotter

at.av ArcView 1 file

at.gra ARC/PLOT plot file for 44\" Versatec plotter

atanno5 geographic place name annotation

atcor correlation of map units

atft faults

atge geology

atlab rock unit label annotation

atleg map legend

atma buried magnetic bodies

atout quadrangle outline and lat/long numbers

atpl political boundaries

atscale 1:500,000 scale bar, title, & citation

atst single-line tributaries

attc latitude/longitude tics for this quadrangle

grid lat/long grid lines for index map

index index map showing quadrangle names and surrounding

countries

vztc latitude/longitude numbers and tics for index map

ay directory containing Puerto Ayacucho 2¡x3¡ quadrangle

(Venezuela part) files

ay.aml ARC/PLOT program for 44\" Versatec plotter

ay.av ArcView 1 file

ay.gra ARC/PLOT plot file for 44\" Versatec plotter

ayanno5 geographic place name annotation

aycor correlation of map units

aycrlbm crossection geology rock unit labels

aycrm crossection geology polygons

ayft faults

ayge geology

aylab rock unit label annotation

aylabcr crossection line and annotation on map

ayleg map legend

aylegpt map legend points

ayma buried magnetic bodies

aymalab buried magnetic bodies

ayout quadrangle outline and lat/long numbers

aypl political boundaries

ayrd roads

ayscale 1:500,000 scale bar, title, & citation

ayst single-line tributaries

aytc latitude/longitude tics for this quadrangle

grid lat/long grid lines for index map

index index map showing quadrangle names and surrounding

countries

vztc latitude/longitude numbers and tics for index map

ca directory containing R'o Caura 2¡ by 3¡ quadrangle files

ca.aml ARC/PLOT program for 44\" Versatec plotter

ca.av ArcView 1 file

ca.gra ARC/PLOT plot file for 44\" Versatec plotter

caanno5 geographic place name annotation

cacor correlation of map units

caft faults

cage geology

calab rock unit label annotation

caleg map legend

calegpt map legend points

cama buried magnetic bodies

caout quadrangle outline and lat/long numbers

capl political boundaries

cascale 1:500,000 scale bar, title, & citation

cast single-line tributaries

catc latitude/longitude tics for this quadrangle

grid lat/long grid lines for index map

index index map showing quadrangle names and surrounding

countries

vztc latitude/longitude numbers and tics for index map

es directory containing La Esmeralda 2¡x3¡ quadrangle

(Venezuela part) files

es.aml ARC/PLOT program for 44\" Versatec plotter

es.av ArcView 1 file

es.gra ARC/PLOT plot file for 44\" Versatec plotter

esanno5 geographic place name annotation

escor correlation of map units

esft faults

esge geology

eslab rock unit label annotation

esleg map legend

eslegpt map legend points

esma buried magnetic bodies

esout quadrangle outline and lat/long numbers

espl political boundaries

esscale 1:500,000 scale bar, title, & citation

esst single-line tributaries

estc latitude/longitude tics for this quadrangle

grid lat/long grid lines for index map

index index map showing quadrangle names and surrounding

countries

vztc latitude/longitude numbers and tics for index map

gu directory containing Guri and southern part of the Tucupita

2¡x3¡ quadrangles files

grid lat/long grid lines for index map

gu.aml ARC/PLOT program for 44\" Versatec plotter

gu.av ArcView 1 file

gu.gra ARC/PLOT plot file for 44\" Versatec plotter

guanno5 geographic place name annotation

gucor correlation of map units

guft faults

guge geology

gulab rock unit label annotation

guleg map legend

gulegpt map legend points

guout quadrangle outline and lat/long numbers

gupl political boundaries

gurd roads

guscale 1:500,000 scale bar, title, & citation

gust single-line tributaries

gutc latitude/longitude tics for this quadrangle

index index map showing quadrangle names and surrounding

countries

vztc latitude/longitude numbers and tics for index map

ma directory containing R'o Mavaca 2¡x3¡ quadrangle (Venezuela

part)

grid lat/long grid lines for index map

index index map showing quadrangle names and surrounding

countries

ma.aml ARC/PLOT program for 44\" Versatec plotter

ma.av ArcView 1 file

ma.gra ARC/PLOT plot file for 44\" Versatec plotter

maanno5 geographic place name annotation

macor correlation of map units

maft faults

mage geology

malab rock unit label annotation

maleg map legend

mama buried magnetic bodies

maout quadrangle outline and lat/long numbers

mascale 1:500,000 scale bar, title, & citation

mast single-line tributaries

matc latitude/longitude tics for this quadrangle

vztc latitude/longitude numbers and tics for index map

pc directory containing Piedra de Cocuy 2¡x3¡ quadrangle

(Venezuela part) files

grid lat/long grid lines for index map

index index map showing quadrangle names and surrounding

countries

pc.aml ARC/PLOT program for 44\" Versatec plotter

pc.av ArcView 1 file

pc.gra ARC/PLOT plot file for 44\" Versatec plotter

pcanno5 geographic place name annotation

pccor correlation of map units

pcft faults

pcge geology

pclab rock unit label annotation

pcleg map legend

pclegpt map legend points

pcma buried magnetic bodies

pcout quadrangle outline and lat/long numbers

pcpl political boundaries

pcscale 1:500,000 scale bar, title, & citation

pcst single-line tributaries

pctc latitude/longitude tics for this quadrangle

vztc latitude/longitude numbers and tics for index map

pi directory containing Ciudad Piar and part of the Ciudad

Bolivar 2¡x3¡ quadrangles files

fnt040 ARC/INFO font file necessary for sag fault line symbol

grid lat/long grid lines for index map

index index map showing quadrangle names and surrounding

countries

pi.aml ARC/PLOT program for 44\" Versatec plotter

pi.av ArcView 1 file

pi.gra ARC/PLOT plot file for 44\" Versatec plotter

pianno5 geographic place name annotation

picor correlation of map units

pift faults

pige geology

pilab rock unit label annotation

pileg map legend

pilegpt map legend points

pima kimberlite area

piout quadrangle outline and lat/long numbers

pipl political boundaries

pird roads

piscale 1:500,000 scale bar, title, & citation

pisr structural lines from SLAR

pist single-line tributaries

pitc latitude/longitude tics for this quadrangle

vztc latitude/longitude numbers and tics for index map

se directory containing Santa Elena 2¡x3¡ quadrangle (Venezuela

part) files

grid lat/long grid lines for index map

index index map showing quadrangle names and surrounding

countries

se.aml ARC/PLOT program for 44\" Versatec plotter

se.av ArcView 1 file

se.gra ARC/PLOT plot file for 44\" Versatec plotter

seanno5 geographic place name annotation

secor correlation of map units

seft faults

sege geology

selab rock unit label annotation

seleg map legend

selegpt map legend points

seout quadrangle outline and lat/long numbers

sepl political boundaries

serd roads

sescale 1:500,000 scale bar, title, & citation

sest single-line tributaries

setc latitude/longitude tics for this quadrangle

vztc latitude/longitude numbers and tics for index map

sf directory containing San Fernando de Apure 2¡x3¡ quadrangle

(Bolivar part) files

grid lat/long grid lines for index map

index index map showing quadrangle names and surrounding

countries

sf.aml ARC/PLOT program for 44\" Versatec plotter

sf.av ArcView 1 file

sf.gra ARC/PLOT plot file for 44\" Versatec plotter

sfanno5 geographic place name annotation

sfcor correlation of map units

sfft faults

sfge geology

sflab rock unit label annotation

sfleg map legend

sflegpt map legend points

sfout quadrangle outline and lat/long numbers for ArcView

sfpl political boundaries

sfscale 1:500,000 scale bar, title, & citation

sfst single-line tributaries

sftc latitude/longitude tics for this quadrangle

vztc latitude/longitude numbers and tics for index map

vz directory containing combined map coverages for Venezuelan

Guayana Shield, all quadrangles

av.mrk ArcView markerset to be copied to the ARCHOME directory

av.txt ArcView textset to be copied to the ARCHOME directory

deposit mineral deposits, prospects and occurrences

equi2geo.prj projection file for converting equidistant conic to

decimal degrees

fnt040 ARC/INFO font file necessary for sag fault line symbol

ge.ai Illustrator 6.0 version of ge.eps

ge.eps ARC/PLOT Postscript plot file for 44\" Versatec plotter

ge.gra ARC/PLOT plot file for 44\" Versatec plotter

geo2equi.prj projection file for converting decimal degrees to

equidistant conic

grid lat/long grid lines for index map

index index map showing quadrangle names and surrounding

countries

mrdsek.mrk ARC/PLOT markerset for other point symbols

myalcgeol.mrk ARC/PLOT markerset for cities, bedding, joint symbols

myplotter.shd ARC/PLOT shadeset for geology patterns

myplt.lin ARC/PLOT lineset for faults, roads, political boundaries

places geographic place names

ra mineral resource permissive areas map A

raanno mineral resource permissive areas map A annotation

rb mineral resource permissive areas map B

rbanno mineral resource permissive areas map B annotation

rbstruct mineral resource permissive areas map B structural

features

scale scalebar and projection information

vz.aml ARC/PLOT program for 44\" Versatec plotter

vz.av ArcView 1 view file

vz.apr ArcView 3 project file

vzcor correlation of map units

vzctry Northeast South America country borders

vzft faults, annotation, joints, and bedding

vzge geology

vzlab rock unit annotation and leaders

vzma buried magnetic bodies

vzout outer edge of combined quadrangles in study area

vzpl study area political boundaries

vzprov Venezuela province boundaries for index map

vzrd roads

vzst single-line tributaries and annotation

vztc latitude/longitude numbers and tics for index map

arcunix7 directory containing ArcView 3 and ARC/INFO 7 directory

vz directory containing combined map coverages for Venezuelan

Guayana Shield, all quadrangles. Same as in

arcunix6/vz.

bull2062 directory containing text and figures from Bulletin 2062

doc

tables.doc Word 5.1 tables 1-2, 4-11

tabside.doc Word 5.1 table 3

mif

b2062con.mif framemaker 3.0p1b table of contents

b2062fnt.mif framemaker 3.0p1b cover 1, cover 2, i, ii, iii

b2062txt.mif framemaker 3.0p1b main body, p. 1-120

rtf

b2062con.rtf rich text (RTF) table of contents

b2062txt.rtf rich text (RTF) main body, p. 3-5

tif

vzget.tif TIF Plate 2, geology, key part

vzge.tif TIF Plate 2, geologic map part

vzmin.tif TIF Plate 6, mineral deposits

txt

b2062con.txt text table of contents

b2062fnt.txt text i, ii

b2062txt.txt text main body, p. 1-72

dlg directory containing Digital Line Graph (DLG) Optional files

cor.dlg correlation of map units in Equidistant Conic projection

cordd.dlg correlation of map units in decimal degrees

ft.dlg faults in Equidistant Conic projection

ftdd.dlg faults in decimal degrees

ge.dlg geology in Equidistant Conic projection

gedd.dlg geology in decimal degrees

ptype.unl rock unit names, descriptions, colors for Versatec

plotter

scale.dlg scale bar in Equidistant Conic projection

scaledd.dlg scale bar in decimal degrees

vzline.unl fault and contact line types

export directory containing directories of ARC/INFO export files and

programs

at directory containing Atabapo quadrangle files

at.aml ARC/PLOT program for 44\" Versatec plotter

at.av ArcView 1 file

at.gra ARC/PLOT 1040 plot file for 44\" Versatec plotter.

This a binary file

atanno5.e00 geographic place name annotation

atcor.e00 correlation of map units

atft.e00 faults

atge.e00 geology

atlab.e00 rock unit label annotation

atleg.e00 map legend

atma.e00 buried magnetic bodies

atout.e00 quadrangle outline and lat/long numbers

atpl.e00 political boundaries

atscale.e00 1:500,000 scale bar, title, & citation

atst.e00 single-line tributaries

attc.e00 latitude longitude tics for this quadrangle

grid.e00 lat/long grid lines for index map

import.aml ARC program for importing coverage

index.e0\* index map showing quadrangle names and surrounding

countries, files 0-1

vztc.e00 latitude longitude tics for index map

ay directory containing Puerto Ayacucho quadrangle files

ay.aml ARC/PLOT program for 44\" Versatec plotter

ay.av ArcView 1 file

ay.gra ARC/PLOT 1040 plot file for 44\" Versatec plotter.

This a binary file

ayanno5.e00 geographic place name annotation

aycor.e00 correlation of map units

aycrlbm.e00 cross section labels

aycrm.e00 cross section arcs

ayft.e00 faults

ayge.e00 geology

aylab.e00 rock unit label annotation

aylabcr.e00 rock unit label annotation for cross section

ayleg.e00 map legend

aylegpt.e00 map legend points

ayma.e00 buried magnetic bodies

aymalab.e00 buried magnetic bodies labels

ayout.e00 quadrangle outline and lat/long numbers

aypl.e00 political boundaries

ayrd.e00 roads

ayscale.e00 1:500,000 scale bar, title, & citation

ayst.e00 single-line tributaries

aytc.e00 latitude longitude tics for this quadrangle

grid.e00 lat/long grid lines for index map

import.aml ARC program for importing coverage

index.e0\* index map showing quadrangle names and surrounding

countries, files 0-1

vztc.e00 latitude longitude tics for index map

ca directory containing R'o Caura quadrangle files

ca.aml ARC/PLOT program for 44\" Versatec plotter

ca.av ArcView 1 file

ca.gra ARC/PLOT 1040 plot file for 44\" Versatec plotter.

This a binary file

caanno5.e00 geographic place name annotation

cacor.e00 correlation of map units

caft.e00 faults

cage.e00 geology

calab.e00 rock unit label annotation

caleg.e00 map legend

calegpt.e00 map legend points

cama.e00 buried magnetic bodies

caout.e00 quadrangle outline and lat/long numbers

capl.e00 political boundaries

cascale.e00 1:500,000 scale bar, title, & citation

cast.e00 single-line tributaries

catc.e00 latitude longitude tics for this quadrangle

grid.e00 lat/long grid lines for index map

import.aml ARC program for importing coverage

index.e0\* index map showing quadrangle names and surrounding

countries, files 0-1

vztc.e00 latitude longitude tics for index map

es directory containing La Esmeralda quadrangle files

es.aml ARC/PLOT program for 44\" Versatec plotter

es.av ArcView 1 file

es.gra ARC/PLOT 1040 plot file for 44\" Versatec plotter.

This a binary file

esanno5.e00 geographic place name annotation

escor.e00 correlation of map units

esft.e00 faults

esge.e00 geology

eslab.e00 rock unit label annotation

esleg.e00 map legend

eslegpt.e00 map legend points

esma.e00 buried magnetic bodies

esout.e00 quadrangle outline and lat/long numbers

espl.e00 political boundaries

esscale.e00 1:500,000 scale bar, title, & citation

esst.e00 single-line tributaries

estc.e00 latitude longitude tics for this quadrangle

grid.e00 lat/long grid lines for index map

import.aml ARC program for importing coverage

index.e0\* index map showing quadrangle names and surrounding

countries, files 0-1

vztc.e00 latitude longitude tics for index map

gu directory containing Guri and Tucupita quadrangle files

grid.e00 lat/long grid lines for index map

gu.aml ARC/PLOT program for 44\" Versatec plotter

gu.av ArcView 1 file

gu.gra ARC/PLOT 1040 plot file for 44\" Versatec plotter.

This a binary file

guanno5.e00 geographic place name annotation

gucor.e00 correlation of map units

guft.e00 faults

guge.e0\* geology files, 0-2

gulab.e00 rock unit label annotation

guleg.e00 map legend

gulegpt.e00 map legend points

guout.e00 quadrangle outline and lat/long numbers

gupl.e00 political boundaries

gurd.e00 roads

guscale.e00 1:500,000 scale bar, title, & citation

gust.e00 single-line tributaries

gutc.e00 latitude longitude tics for this quadrangle

import.aml ARC program for importing coverage

index.e0\* index map showing quadrangle names and surrounding

countries, files 0-1

vztc.e00 latitude longitude tics for index map

ma directory containing R'o Mavaca quadrangle files

grid.e00 lat/long grid lines for index map

import.aml ARC program for importing coverage

index.e0\* index map showing quadrangle names and surrounding

countries, files 0-1

ma.aml ARC/PLOT program for 44\" Versatec plotter

ma.av ArcView 1 file

ma.gra ARC/PLOT 1040 plot file for 44\" Versatec plotter.

This a binary file

maanno5.e00 geographic place name annotation

macor.e00 correlation of map units

maft.e00 faults

mage.e00 geology

malab.e00 rock unit label annotation

maleg.e00 map legend

mama.e00 buried magnetic bodies

maout.e00 quadrangle outline and lat/long numbers

mascale.e00 1:500,000 scale bar, title, & citation

mast.e00 single-line tributaries

matc.e00 latitude longitude tics for this quadrangle

vztc.e00 latitude longitude tics for index map

pc directory containing Piedra de Cocuy quadrangle files

grid.e00 lat/long grid lines for index map

import.aml ARC program for importing coverage

index.e0\* index map showing quadrangle names and surrounding

countries, files 0-1

pc.aml ARC/PLOT program for 44\" Versatec plotter

pc.av ArcView 1 file

pc.gra ARC/PLOT 1040 plot file for 44\" Versatec plotter.

This a binary file

pcanno5.e00 geographic place name annotation

pccor.e00 correlation of map units

pcft.e00 faults

pcge.e00 geology

pclab.e00 rock unit label annotation

pcleg.e00 map legend

pclegpt.e00 map legend points

pcma.e00 buried magnetic bodies

pcout.e00 quadrangle outline and lat/long numbers

pcpl.e00 political boundaries

pcscale.e00 1:500,000 scale bar, title, & citation

pcst.e00 single-line tributaries

pctc.e00 latitude longitude tics for this quadrangle

vztc.e00 latitude longitude tics for index map

pi directory containing Ciudad Piar and Ciudad Bolivar

quadrangle files

fnt040 ARC/INFO font file necessary for sag fault line symbol

grid.e00 lat/long grid lines for index map

import.aml ARC program for importing coverage

index.e0\* index map showing quadrangle names and surrounding

countries, files 0-1

pi.aml ARC/PLOT program for 44\" Versatec plotter

pi.av ArcView 1 file

pi.gra ARC/PLOT 1040 plot file for 44\" Versatec plotter.

This a binary file.

pianno5.e00 geographic place name annotation

picor.e00 correlation of map units

pift.e00 faults

pige.e0\* geology, 0-2

pilab.e00 rock unit label annotation

pileg.e00 map legend

pilegpt.e00 map legend points

pima.e00 buried magnetic bodies

piout.e00 quadrangle outline and lat/long numbers

pipl.e00 political boundaries

pird.e00 roads

piscale.e00 1:500,000 scale bar, title, & citation

pisr.e00 structural lines from SLAR

pist.e00 single-line tributaries

pitc.e00 latitude longitude tics for this quadrangle

vztc.e00 latitude longitude tics for index map

se directory containing Santa Elena quadrangle files

grid.e00 lat/long grid lines for index map

import.aml ARC program for importing coverage

index.e0\* index map showing quadrangle names and surrounding

countries, files 0-1

se.aml ARC/PLOT program for 44\" Versatec plotter

se.av ArcView 1 file

se.gra ARC/PLOT 1040 plot file for 44\" Versatec plotter.

This a binary file

seanno5.e00 geographic place name annotation

secor.e00 correlation of map units

seft.e00 faults

sege.e0\* geology, 0-1

selab.e00 rock unit label annotation

seleg.e00 map legend

selegpt.e00 map legend points

seout.e00 quadrangle outline and lat/long numbers

sepl.e00 political boundaries

serd.e00 roads

sescale.e00 1:500,000 scale bar, title, & citation

sest.e00 single-line tributaries

setc.e00 latitude longitude tics for this quadrangle

vztc.e00 latitude longitude tics for index map

sf directory containing San Fernando quadrangle files

grid.e00 lat/long grid lines for index map

import.aml ARC program for importing coverage

index.e0\* index map showing quadrangle names and surrounding

countries, files 0-1

sf.aml ARC/PLOT program for 44\" Versatec plotter

sf.av ArcView 1 file

sf.gra ARC/PLOT 1040 plot file for 44\" Versatec plotter.

This a binary file

sfanno5.e00 geographic place name annotation

sfcor.e00 correlation of map units

sfft.e00 faults

sfge.e00 geology

sflab.e00 rock unit label annotation

sfleg.e00 map legend

sflegpt.e00 map legend points

sfout.e00 quadrangle outline and lat/long numbers

sfpl.e00 political boundaries

sfscale.e00 1:500,000 scale bar, title, & citation

sfst.e00 single-line tributaries

sftc.e00 latitude longitude tics for this quadrangle

vztc.e00 latitude longitude tics for index map

vz directory containing export files for combined coverages

avmrk.e00 ArcView markerset to be copied to the ARC HOME directory

avtxt.e00 ArcView textset to be copied to the ARC HOME directory

deposit.e0\* mineral deposits, prospects and occurrences, files 0-2

equi2geo.prj projection file for converting equidistant conic to

decimal degrees

fnt040 ARC/INFO font file necessary for sag fault line symbol

ge.gra ARC/PLOT 1040 plot file for 44\" Versatec plotter.

This a binary file

geo2equi.prj projection file for converting decimal degrees to

equidistant conic

grid.e00 lat/long grid lines for index map

import.aml ARC script for importing all coverages

index.e0\* index map showing quadrangle names and surrounding

countries, files 0-1

mrdsek.e00 ARC/PLOT markerset for other point symbols

myalcgeol.e00 ARC/PLOT markerset for cities, bedding, joint symbols

myplotter.e00 ARC/PLOT shadeset for geology patterns

myplt.e00 ARC/PLOT lineset for faults, roads, political boundaries

places.e00 geographic place names

ptpat.e00 geology polygon lookup table, plotter patterns

ptpl.e00 point symbol lookup table

ptype.e00 geology polygon lookup table, Versatec colors

ra.e0\* mineral resource permissive areas map A

raanno.e00 mineral resource permissive areas map A annotation

rb.e0\* mineral resource permissive areas map B files, 0-1

rbanno.e00 mineral resource permissive areas map B annotation

rbstruct.e00 mineral resource permissive areas map B structural

features

scale.e00 scalebar and projection information

vz.aml ARC/PLOT program for 44\" Versatec plotter

vz.av ArcView 1 view file

vz.apr ArcView 3 project file

vzcor.e00 correlation of map units

vzctry.e0\* Northeast South America country borders, 0-1

vzft.e00 faults, annotation, joints and bedding

vzge.e00 geology files, 0-9

vzlab.e0\* rock unit annotation and leaders files, 0-2

vzline.e00 lineset for Arc/Edit, Arc/Plot, Versatec plots

vzma.e00 buried magnetic bodies

vzout.e00 outer edge of combined quadrangles in study area

vzpl.e00 study area political boundaries

vzprov.e00 Venezuela province boundaries for index map

vzrd.e00 roads

vzst.e0\* single-line tributaries and annotation files, 0-2

vztc.e00 latitude/longitude numbers and tics for index map

PROJECT OVERVIEW

Conversion of the Venezuela maps to a computerized digital format was
undertaken for the following reasons:

1\) The digital format facilitates the presentation and analysis of
earth-science data. Digital maps can be displayed at any scale or
projection, whereas a paper map has a fixed scale and projection.
However, the maps on this disc are not intended to be used at any scale
more detailed than 1:500,000.

A geographic information system (GIS) allows combining and overlaying of
layers for analysis of spatial relations not readily apparent in the
standard paper publication. Digital data on geology, geophysics, and
geochemistry can be combined to create useful derivative products.

2\) The digital format was used to facilitate publication in both paper
and electronic form. For the Río Caura paper map publication (Brooks and
others, 1995), digital images were sent to the Gerber plotter, a
vector-to-film processor. The other 1:500,000-scale MF maps were
reproduced photographically from electrostatic plotter output on clear
mylar. The published digital formats include this CD-ROM and ARC/INFO
Export files to be located on the World Wide Web on the Internet.

HISTORY OF THE MAPS

The data in this CD-ROM are based on a mineral resource assessment of
the Venezuelan Guayana Shield, conducted between 1987 and 1991 by the
U.S. Geological Survey and Corporación Venezolana de Guayana, Técnica
Minera, (USGS, 1993). The Venezuelan Shield occupies about 415,000 sq km
in the south and east part of Venezuela. The study area is bounded on
the north by the Río Orinoco. It includes all of the Territorio Federal
Amazonas, Estado Bolívar, and part of Estado Delta Amacuro. The original
resource assessment publication USGS Bulletin 2062 consists of 121 pages
of text and figures as well as eight full-color maps:

Geographic

Geologic and tectonic

Bouguer gravity

Two mineral-occurrence maps

Side-looking airborne radar image

Two permissive domain maps

The side-looking airborne radar image and the Bouguer gravity map are
not included in this CD-ROM. The geology layer from the 1993 Bulletin
was revised and published as a series of MF and I maps:

Quadrangles Map Authors

\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--

Guri + Tucupita MF-2242 Cox and others, 1993

Ciudad Piar + MF-2246 Stewart and others, 1994

Ciudad Bolivar

San Fernando de MF-2247 Stewart, 1994

Apure

Santa Elena unpublished data Floyd Gray and others, 1995

R'o Caura I-2537 Brooks and others, 1995

Puerto Ayacucho MF-2245 Wynn and others, 1994

La Esmeralda MF-2244 Wynn and others, 1994

Atabapo MF-2240 Wynn and others, 1994

R'o Mavaca MF-2241 Wynn and others, 1994

Piedra de Cocuy MF-2243 Wynn and others, 1994

The digital map files on this CD-ROM were used to create the above
publications. They subsequently underwent minor revisions to reconcile
conflicting rock unit names and to view correctly in ArcView.

USGS BULLETIN 2062 TEXT AND FIGURES FILES

The text of the 1993 USGS Bulletin 2062 is available in several
Framemaker, Rich Text Word, and TIF files on the CD-ROM. The text in the
following files may vary slightly from the final publication. Some of
the files listed below duplicate parts of each other but in different
formats. The tif files were created by scanning the published Plates 2
and 6. Plate 2 is split into two files. The other Plates have not been
scanned.

size

file name Kb format content

b2062con.mif 154 framemaker 3.0p1b table of contents

b2062con.txt 7.6 text table of contents

b2062con.rtf 16 rich text (RTF) table of contents

b2062fnt.mif 134 framemaker 3.0p1b cover 1, cover 2, i, ii, iii

b2062fnt.txt 3.4 text i, ii

b2062txt.mif 1208 framemaker 3.0p1b main body, p. 1-120

b2062txt.txt 251 text main body, p. 1-72

b2062txt.rtf 9.6 rich text (RTF) main body, p. 3-5

tables.doc 113 Word 5.1 tables 1-2, 4-11

tabside.doc 183 Word 5.1 table 3

vzge.tif 93000 TIF Plate 2, geologic map part

vzget.tif 20000 TIF Plate 2, geology, key part

vzmin.tif 87000 TIF Plate 6, mineral deposits

REFERENCES FOR THIS DISC

Bellizzia-G., Alirio, Pimentel-M., Nelly, and Bajo-O., R., 1976, Mapa
geológico estructural de Venezuela: Ministerio de Minas e Hidrocarburos,
Dirección Geológica, Caracas, Venezuela, scale 1:500,000.

Briceño, H.O., 1982, Application of remote sensing to diamond placer
exploration in a tropical jungle environment, Caroní River, Venezuela:
Golden, Colo., Colorado School of Mines, Ph.D dissertation, 176 p.

Brooks, W.E., Sidder, G.B., Wynn, J.C., Cox, D.P., Stewart, J.H., and
Schruben, P.G., 1995, Geologic map of the Río Caura 2° by 3° quadrangle,
estado Bolivar, Venezuela: U.S. Geological Survey Miscellaneous
Investigations Map I-2537.

Brooks, W.E., Tosdal, R.M., and Nuñez, F., in press, Gold resources of
the Río Chivao study area, Estado Bolívar, Venezuela, [in]{.underline}
Sidder, G.B., García G., Andrés, and Stoeser, J.W., eds., Geology and
mineral deposits of the Venezuelan Guayana Shield: U.S. Geological
Survey Bulletin 2124.

Cox, D.P., Gray, Floyd, Acosta, Juan, Stewart, J.H., Arespón, Jesús,
Brooks, W.E., Franco, Luis, Salazar, Edixon, and Lopez, Yolanda, 1993,
Geologic map of the Guri and southern part of the Tucupita 2°x3°
quadrangles, Bolivar State, Venezuela: U.S. Geological Survey
Miscellaneous Field Studies Map MF-2242, scale 1:500,000.

Environmental Systems Research Institute, Inc., 1990, ARC/INFO 5.0 User
Manuals: Redlands, Calif.

Environmental Systems Research Institute, Inc., 1992, ArcView User\'s
Guide: Redlands, Calif.

Gaudette, H.E., Mendoza, Vicente, Hurley, P.M., and Fairbairn, H.W.,
1978, Geology and age of the Parguaza rapakivi granite, Venezuela:
Geological Society of America Bulletin, v. 89, p. 1335-1340.

Gaudette, H.E., and Olszewski, W.J., Jr., 1985, Geochronology of the
basement rocks, Amazonas Territory, Venezuela and the tectonic evolution
of the western Guiana Shield: Geologie en Mijnbouw, v. 64, p. 131-143.

Ghosh, S.K., 1985, Geology of the Roraima Group and its implications:
Simposium Amazonico, 1st, Caracas, 1981; Ministerio de Energía y Minas,
Dirección de Geología Boletín de Geología Publicación Especial 10, p.
31-50

Green, G.N., and Selner, G.I., 1988, GSMARC\--A program and procedure to
convert GSMAP data bases into ARC/INFO coverages; GSDARC, a counterpart
program for GSDRAW data bases and an ARC/INFO procedure to topologically
structure resultant data: U.S. Geological Survey Open-File Report
88-430-A (16 p.) and B (a 5.25-inch diskette).

Marcano, Iris, Lugo, Elis, and Rivero, Nelson, 1991, Geología y
geomorfología de la frontera con Colombia, entre la Piedra de Cocuy y
Maroa, al suroeste del Territorio Federal Amazonas, Venezuela:
CVG-TECMIN Grupo Inventario internal report.

Martínez, Felix, 1991, Mapa geológico del area Río Cunucunuma: Congreso
Geológico de la Frontiera de Venezuela, San Cristobal, Venezuela,
September 9-13, 1991.

McCandless, G.C., 1962, Reconnaissance geology of the northwest region
of the State of Bolívar, Venezuela: Caribbean Journal of Science, v. 2,
no. 4, p. 145-155.

Mendoza, Vicente, Moreno, L.A., Barrios, Fernando, Rivas, Duggar,
Martínez, Jesús, Lira, Pedro, Sardi, Gustavo, and Ghosh, S.K., 1977,
Geología de la parte norte del Territorio Federal Amazonas, Venezuela
(informe en progreso): Congreso Geológico Venezolano, 5th, Caracas,
1977, Memoria, v.1, p. 363-404.

Mendoza-S., Vicente, 1977, Evolución tectónica del Escudo de Guayana,
[in]{.underline} Petzall, C., ed., Memoria Segundo \[II\] Congreso
Latinoamericano de Geología, Tomo III, Caracas, November 11-16, 1973:
Venezuela, Dirección de Geología, Boletin de Geología, Publicación
Especial 7, v. 3, p. 2237-2270.

Reid, A.R., and Bisque, R.E., 1975, Stratigraphy of the diamond-bearing
Roraima Group, Estado Bolívar, Venezuela: Colorado School of Mines
Quarterly Bulletin, v. 70, no. 1, p. 61-82.

Schruben, P.G., 1986, MRDS-REV, a mineral occurrence/deposit database
for microcomputer: U.S. Geological Survey Open-File Report 86-34, 55 p.

Schruben, P.G., 1995, Geology of the Venezuelan Guayana Shield at
1:500,000 scale\--A digital representation of maps published by the U.S.
Geological Survey: U.S. Geological Survey Open-File Report 95-493, 11 p.
and a web page.

Selner, G.I., and Taylor, R.B., 1987, GSDRAW and GSMAP version 4.0;
prototype programs for the IBM PC and compatible microcomputers to
assist compilation and publication of geologic maps and illustrations:
U.S. Geological Survey Open-File Report 87-496-A (documentation, 90 p.),
B (executable 5.25-inch diskette), C (source-code 5.25-inch diskette),
and D (two executable utility program diskettes, each 5.25 inches).

Sidder, G.B., and Mendoza-S., Vicente, 1991, Geology of the Venezuelan
Guayana Shield and its relation to the entire Guayana Shield: U.S.
Geological Survey Open-File Report 91-141, 59 p., 2 plates.

Sidder, G.B., García G., Andrés, and Stoeser, J.W., eds., in press,
Geology and mineral deposits of the Venezuelan Guayana Shield: U.S.
Geological Survey Bulletin 2124.

Soares, M.A., 1985, Estudio petrográfico de la estructura alcalina La
Churuata, Territorio Federal Amazonas: Congreso Geológico Venezolano,
6th, Caracas, Memoria, v. 4, p. 2117-2158.

Stewart, J.H., 1994, Geologic map of part of the San Fernando de Apure
2°x3° quadrangle, Venezuela: U.S. Geological Survey Miscellaneous field
studies map MF-2247.

Stewart, J.H., Martínez, Félix, and Brooks, W.E., 1994, Geologic map of
the Ciudad Piar and part of the Ciudad Bolivar 2°x3° quadrangles,
Bolivar State, Venezuela: U.S. Geological Survey Miscellaneous Field
Studies Map MF-2246, scale 1:500,000.

Teggin, D.E., Martínez, M., and Palacios, G., 1985, Un estudio
preliminar de las diabasas del Estado Bolívar, Venezuela,
[in]{.underline} Espejo C., Aníbal, Ríos-F., J.H., Pimentel de
Bellizzia, Nelly, and Pardo, A.S., eds., Petrología, geoquímica, y
geocronología, VI Congreso Geológico Venezolano, Caracas, Memoria, v. 4,
p. 2159-2206.

U.S. Geological Survey, 1986, Digital line graphs from 1:24,000-scale
maps: U.S. Geological Survey US GeoData Data Users Guide 1, 109 p.

U.S. Geological Survey, 1987, Digital line graphs from 1:2,000,000-scale
maps: U.S. Geological Survey US GeoData Data Users Guide 3, 71 p.

U.S. Geological Survey, 1989, Digital line graphs from 1:100,000-scale
maps: U.S. Geological Survey US GeoData Data Users Guide 2, 88 p.

U.S. Geological Survey and Corporación Venezolana de Guayana, Técnica
Minera, C.A., 1993, Geology and Mineral Resource Assessment of the
Venezuelan Guayana Shield: U.S. Geological Survey, Bulletin 2062, 121 p.
8 plates.

Wentworth, C.M., and Fitzgibbon, T.T., 1991, Alacarte user manual,
version 1.0: U.S. Geological Survey Open-File Report 91-587-C, 267 p.

Wynn, J.C., Olmore, S.D., Mendoza, Vicente, Martínez, Miguel, Rincón,
Haydée, García, Andrés, Rivero, Nelson, Rendón, Inés, Marcano, Iris,
Lugo, Elis, and Schruben, P.G., 1994, Geologic map of the Venezuela part
of the Atabapo 2°x3° quadrangle, Amazonas Federal Territory, Venezuela:
U.S. Geological Survey Miscellaneous Field Studies Map MF-2240, scale
1:500,000.

Wynn, J.C., Olmore, S.D., Mendoza, Vicente, García, Andrés, Martínez,
Miguel, and Schruben, P.G., 1994, Geologic map of the Venezuela part of
the Río Mavaca 2°x3° quadrangle, Amazonas Federal Territory, Venezuela:
U.S. Geological Survey Miscellaneous Field Studies Map MF-2241, scale
1:500,000.

Wynn, J.C., Olmore, S.D., Mendoza, Vicente, García, Andrés, Martínez,
Miguel, Tovar, Frank, Rendón, Inés, Rincón, Haydée, Martínez, Félix,
Lugo, Elis, and Schruben, P.G., 1994, Geologic map of the Venezuela part
of the La Esmeralda 2°x3° quadrangle, Amazonas Federal Territory,
Venezuela: U.S. Geological Survey Miscellaneous Field Studies Map
MF-2244, scale 1:500,000.

Wynn, J.C., Olmore, S.D., Mendoza, Vicente, García, Andrés, Rendón,
Inés, Estanga, Yasmin, Rincón, Haydée, Martínez, Félix, Lugo, Elis,
Rivero, Nelson, and Schruben, P.G., 1994, Geologic map of the Venezuela
part of the Puerto Ayacucho 2°x3° quadrangle, Amazonas Federal
Territory, Venezuela: U.S. Geological Survey Miscellaneous Field Studies
Map MF-2245, scale 1:500,000.

Wynn, J.C., Olmore, S.D., Mendoza, Vicente, Rincón, Haydée, García,
Andrés, Rivero, Nelson, Rendón, Inés, Gray, Floyd, Marcano, Iris, Lugo,
Elis, and Schruben, P.G., 1994, Geologic map of the Venezuela part of
the Piedra de Cocuy 2°x3° quadrangle, Amazonas Federal Territiory,
Venezuela: U.S. Geological Survey Miscellaneous Field Studies Map
MF-2243, scale 1:500,000.

DIGITAL PRODUCTION TECHNIQUES

The linework for all the quadrangles was originally digitized by Jeff
Wynn with GSMAP (Selner and Taylor, 1987), a USGS-authored map editing
and publishing program. Conversion from GSMAP to ARC/INFO was
accomplished with GSMARC (Green and Selner, 1988). The three northern
quadrangles were later re-scanned on an Tektronix 4991 autovectorizing
drum scanner by Paul Schruben from the geologists\' revised drawings.
The arcs and polygons were tagged in ARC/INFO and the oriented point
symbols such as bedding and joint symbols were created with Alacarte
(Wentworth and Fitzgibbon, 1991).

MAP PROJECTION

The map projection is Equidistant Conic with the following parameters
for all quadrangles:

Sphere Clarke 1866 spheroid

1st standard parallel 9 0 0.000

2nd standard parallel 4 0 0.000

central meridian -66 0 0.000

latitude of projection\'s origin 0 0 0.000

false easting (meters) 0.00000

false northing (meters) 0.00000

CAUTIONS RELATING TO USE OF THE MAPS

One of the advantages of digital maps is the ability to change the map
scale. However, the users of this disc should respect the intentions of
the authors and recognize certain limitations of digital maps. The
Venezuelan MF series maps on this disc are intended to be used at a
scale of 1:500,000; they are not intended to be used at a more detailed
(larger) scale. A Venezuela 2°x3° degree quadrangle measures about 17
inches high by 26 inches wide at 1:500,000 scale.

The \"quadrangle\" maps in this publication cover somewhat more or less
than 2°x3° depending on the specific map. For instance, the Guri map
(Cox and others, 1993) contains all of the Guri quadrangle and the
southern part of the Tucupita quadrangle. The entire study area in the
southeast part of Venezuela, known as the Venezuelan Guayana Shield, is
about 36 inches tall at 1:1 million scale, which is the published scale
for Bulletin 2062 (USGS and Corporación Venezolana de Guayana, Técnica
Minera, C.A., 1993).

Furthermore, the geologic map is primarily a bedrock map, which depicts
geologic materials present beneath the soil or relatively thin mantles
of surficial deposits, not necessarily the surficial materials
themselves. Indeed, the study area contains so much surficial cover and
standing water that much of the mapping was accomplished with
geophysical methods as opposed to directly examining rock outcrops.

ONLINE FILES

Some of the files on this CD will be available on the internet at the
following internet address:

http://minerals.er.usgs.gov/vz/dds-46.html

The page will also list any bugs and errors discovered in the CD-ROM
after release.

GRAPHICS FORMATS AVAILABLE ON THE DISC

1\) ARC/INFO Export

These coverages are used for spatial analysis, derivative products, and
to-scale plots on the Versatec electrostatic plotter. Compatible with
Environmental Systems Research Institute\'s ARC/INFO Version 6.1.2 or
later. The files are simple text and should be transmitted in ASCII mode
except for the \*.gra plot files, which are binary.

2\) ARC/INFO Graphics, Adobe Illustrator, Portable Document Format
(PDF), and Postscript formats

The geologic map in ARC/INFO Graphics, Adobe Illustrator, PDF, and
Postscript formats are located in directory "arcunix7/vz". All are
derived from the ARC/INFO ".gra" file using the POSTSCRIPT command.

3\) ArcView format

ArcView is an easy-to-use graphics display package by the authors of
ARC/INFO. This CD-ROM contains ArcView coverages for both UNIX and
Microsoft Windows 3.x. It also contains export files that can be copied
to other ARC/INFO platforms and imported to ArcView. ArcView 1 keys are
in the "arcunix6" directory. The ArcView 3 key for the "vz" directory is
in the "arcunix7"directory.

4\) U.S. Geological Survey Digital Line Graph (DLG) Optional format
(U.S. Geological Survey, 1986, 1987, and 1989).

The DLG Optional format is a U.S. Geological Survey standard for storing
topologically structured files. It results in a compact ASCII file that
is compatible with a variety of graphics software. Only the geology,
faults, and correlation chart layers were converted to this format. The
polygons and arcs are tagged, but the text annotation is not present
because the DLG conversion software does not support annotation.

5\) Tagged image file format (TIFF)

The geologic map and mineral deposit maps from Bulletin 2062 were
scanned on a color scanner and saved as TIFF files. The larger files are
compressed under PKZIP.

ARCVIEW AND ARC/INFO FILES

These files are compatible with ArcView 1 and ARC/INFO Version 6.1.2 or
later. The files are contained in 11 directories. Ten of those
directories contain coverages for the individual quadrangle
publications. The eleventh directory, \"vz\", contains the same
information but in the form of a combined map with all the quadrangles
tiled together into a single coverage. ArcView 1 keys are in the
"arcunix6" directory. The ArcView 3 key for the "vz" directory is in the
"arcunix7"directory. There are no ArcView 3 keys for the individual
quadrangles.

The coverages for the individual quadrangles have the same features as
the combined coverage. The only differences are in some of the file
names. For instance, the place names and city points in the individual
quadrangles are stored in files called \"\*anno5.e00\" as opposed to
\"places.e00\" for the combined coverage.

The 11 directory structure is repeated in each of three formats: export,
raw UNIX, and PC ARCVIEW.

EXPORT FILES

The export files are stored in the \"export\" directory. The same export
files are used for both ARCVIEW and ARC/INFO. Each directory contains an
IMPORT.AML program which imports all the coverages, lookup tables, etc.
The \"vz\" directory contains lookup tables and markersets necessary for
plotting the individual quadrangles. Before launching ARCVIEW, the
\"av.mrk\" and \"av.txt\" files should be copied to the ARCVIEW home
directory, usually the root or login directory.

The directories containing the export files on the CD are actually
ARC/INFO workspaces for UNIX. For other platforms it may be necessary to
launch ARC/INFO, create each of the 11 workspaces and import the
coverages from those new workspaces. For instance, for the \"vz\"
directory:

arc

cw vz

q

cd vz

cp /pdd/dds46/export/vz/\* .

arc

&r import

The directory structure on the CD is as follows:

export main directory

at Atabapo

ay Puerto Ayacucho

ca R'o Caura

es La Esmeralda

gu Guri, Tucupita

ma R'o Mavaca

pc Piedra de Cocuy

pi Ciudad Piar, Ciudad Bolivar

se Santa Elena

sf San Fernando de Apure

vz combined coverages. Also necessary to plot individual quads.

RAW UNIX COVERAGES:

The raw coverages are in directory \"arcunix6\" and "arcunix7". These
can be copied to your UNIX machine with the following command:

cp -r /pdd/dds46/arcunix7

PC ARCVIEW COVERAGES:

The PC ARCVIEW coverages are stored in directory \"arcpc\". These files
were converted directly from the UNIX version with the C program PCWKSP.

RUNNING THE PLOT PROGRAMS

Each of the 11 directories contains a plot program for that area. The
plot programs rely on lookup tables in the \"vz" combined coverages
directory. So the \"vz" combined coverages directory should be copied or
imported to hard disk before executing the plot program. The resulting
.gra file was converted to PostScript .eps with the ARC POSTSCRIPT
command. The polygon colors are for a Versatec plotter or display
screen.

INSTALLING ARCVIEW 1

This section contains instructions for installing and launching

ArcView 1 for Windows and launching instructions for ArcView 1 for UNIX.

Installation instructions for ArcView 1 for Microsoft Windows:

1\) Please observe the following system requirements:

80386 or better CPU

Math coprocessor recommended

Windows 3.0 or higher but not Windows 95

4 Mb of RAM, 8 strongly recommended

15 Mb of disk space

Super VGA graphics system, 256 colors, 640x480 pixels minimum,

1024x768 pixels strongly recommended

Microsoft compatible mouse

Windows-supported printer

2\) Decide where you are going to put ArcView 1 on your hard drive. You
must have 15 Mb of hard disk space.

3\) Launch Windows. Launch the File Manager. Use the File Manager to
find the CD-ROM drive and the \\DDS46\\ARCVIEW directory. Double-click
on

ARCVIEW.EXE. This starts the self-installing procedure. At the licensing
agreement document select the File menu, Exit. ARCVIEW asks for a hard
disk drive letter designation and a directory name to store the program.
The default is \\ARCVIEW1.

4\) When the install finishes, ArcView will tell you to examine
SETUP.TXT and use it to modify AUTOEXEC.BAT and CONFIG.SYS. Exit from
Windows and use the following instructions modified from SETUP.TXT.

Add the following environment variables to the C:\\AUTOEXEC.BAT file:

set AVHOME=c:\\arcview1 (or wherever you decide to put it)

set PATH=%PATH%;%AVHOME%\\bin (Add Arcview1\'s bin directory

to the path )

set HOME=c:\\arcview1 (or wherever you decide to put it)

set TEMP=c:\\temp (Make sure the directory

exists. A RAM disk works the

best, i.e, TEMP=d:\\. This

variable should already be

present if Windows has been

installed.)

Add the following line to the C:\\CONFIG.SYS file:

FILES=65

Rename the original lineset. Copy the custom lineset from the DDS-46 CD-
ROM.

CD C:\\ARCVIEW1\\SYMBOLS

REN AV.LIN AV_ORIG.LIN

COPY D:\\DDS46\\DATAFILE\\AVPCCOV\\AV.LIN

5\) Launch Windows. Launch the File Manager again and copy the
DDS46\\ARCPC directory to your hard disk. This step is optional but
ArcView runs very slowly if the coverages are located on the CD-ROM.

Double-click on the ArcView icon. Navigate the drive and directory menus
to D:\\DDS46\\DATAFILE. Double-click on the COSTA.AV view. ArcView will
ask to search for the GEOL coverage. Select \"Yes\". Navigate to the
AVPCCOV folder and double-click on the GEOL file. The ArcView Teacher
will automatically find the full path to the rest of the coverages and
launch the view. Select the \"File\" menu, \"Save As\". Save the view so
the next time you launch it, the path will be remembered.

USING ARCVIEW 1

The CD-ROM includes coverages that can be displayed with ArcView 1
(Environmental Systems Research Institute, Inc., 1992). ArcView is an
easy-to-use graphics display package by the authors of ARC/INFO. ArcView
displays the same coverages and images as ARC/INFO. ArcView 1 is
available for UNIX Macintosh and Microsoft Windows 3.x computers. This
CD-ROM contains ArcView 1 for Windows 3.x programs but not ArcView for
UNIX or Macintosh programs. It does, however, contain coverages and
views for both types of computers.

See \"Installing ArcView 1\" for instructions on installing and
launching ArcView 1. After ArcView is launched, the Table of Contents or
map key appears on the left and the map on the right. ArcView has a
time-saving feature called interruptible re-draw. This means that the
tools, menu items and themes in the Table of Contents are selectable
even while ArcView is re-drawing the map. A mouse-click or mouse-drag
will interrupt the drawing and take effect within a few seconds. There
is no need to wait for complicated maps to finish drawing if you already
know what you want to do next.

The initial width of the Table of Contents is too narrow to see all the
text in the key. The width can be increased by dragging on the edge of
the table with the mouse. Increasing the width of the Table of Contents
causes it to overlap the map, but the map can be brought to the
foreground by clicking on its title bar or edge.

The individual layers (data themes) in the Table of Contents are turned
on and off in the display by selecting the checkboxes along the left
side of the map key. Legends below individual themes can be turned on
and off by dragging on the triangle on the right side of the key. Colors
of points, lines, and polygon fill can be changed by double-clicking a
theme, selecting the legend checkbox in the Properties dialog, then
double-clicking on the color.

Zooming in and out are accomplished in many ways in ArcView. One way is
to select a theme or themes by single-clicking on the items in the Table
of Contents so they appear slightly raised. Single-click again to
de-select them. Choose just the items you want to zoom to, then select
the \"fit-selected-features-to-window\" icon, which is the second icon
from the left in the map window. It looks like a down arrow over a stack
of paper. For instance, the \"Venezuela national boundary\" theme will
give the widest view, \"Index map\" the next widest, \"Geology, all
quadrangles\" the next widest, and individual quadrangles the smallest.
In each quadrangle, the Scale bar theme zooms out to see all the text
and map. This is the default selection as the CD is shipped.

Another way to zoom in is with the \"zoom-to-a-box\" tool on the tool
palette. The tool palette can be brought to the foreground with the
\"Windows\" menu, \"Tools\...\" item. Just select the dashed-line-box
tool, which is the second from the bottom on the left, then drag in a
diagonal movement across the area you wish to zoom to.

If you view the \"Rock unit names\" theme, be sure to turn on the \"Rock
unit name leaders\" as well. Otherwise some unit names appear to float
in the wrong unit.

The order of layers in the Table of Contents is critical. All layers are
opaque, and the color-fill polygons obscure everything beneath them. For
this reason, color-fill themes are positioned lowest on the key and
duplicated as non-filled versions higher up in the key. For instance,
\"Geology polygons\" is low in the Table of Contents because it obscures
everything beneath it. There is also a non-filled version called
\"Geology arcs\" higher up in the key. Should it be necessary to change
the order of items in the Table of Contents, they can be dragged to a
new position with the mouse. For instance, \"Index map, colored
countries\" is positioned fairly high in the key for a color-fill theme.
To draw geology outlines on top of it, just drag the index map theme to
a position below the geology outlines theme.

To create hard copy of the ArcView 1 graphics screen, select the camera
icon on the main display screen. This creates an encapsulated PostScript
(EPS) file of the display image, which can be printed with standard
commercial graphics software.

Use the \"File\" menu, \"Open\...\" item to select other views:

Area file name

\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--

Venezuelan Guayana Shield, all quadrangles vz.av

Guri and southern part of the Tucupita 2¡x3¡ quadrangles gu.av

Ciudad Piar and part of the Ciudad Bolivar 2¡x3¡ quadrangles pi.av

San Fernando de Apure 2¡x3¡ quadrangle (Bolivar part) sf.av

Santa Elena 2¡x3¡ quadrangle (Venezuela part) se.av

R'o Caura 2¡ by 3¡ quadrangle ca.av

Puerto Ayacucho 2¡x3¡ quadrangle (Venezuela part) ay.av

La Esmeralda 2¡x3¡ quadrangle (Venezuela part) es.av

Atabapo 2¡x3¡ quadrangle (Venezuela part) at.av

R'o Mavaca 2¡x3¡ quadrangle (Venezuela part) ma.av

Piedra de Cocuy 2¡x3¡ quadrangle (Venezuela part) pc.av

ARCVIEW 1 FILES

The following table shows the ArcView 1 table of contents items and the
source coverages:

ArcView views and themes file name

\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--

Venezuelan Guayana Shield, all quadrangles vz.av

Venezuela national boundary vzctry

Venezuela province boundary vzprov

Scale bar annotation scale

Scale bar scale

Place names places

Place points places

Roads vzrd

Outer quad outline vzout

Outer quad outline, lat/long numbers vzout

Latitude/longitude tics vztc

Index map annotation index

Index map lat/long grid only grid

Index map, colored countries, lat/long grid index

Streams annotation vzst

Streams vzst

Mineral deposits deposit

Linear features annotation vzft

Linear features vzft

A. Permissive domains annotation raanno

A. Permissive domains leaders raanno

A. Permissive domains for selected Fe, Au, Sn, ra

Cu deposits

A. Permissive domains poly arcs only ra

B. Permissive domains structure annotation rbstruct

B. Permissive domains structure lines rbstruct

B. Permissive domains annotation rbanno

B. Permissive domains leaders rbanno

B. Permissive domains for selected Pb-Zn, Ni-Cu, rb

diamond, kaolin deposits

B. Permissive domains poly arcs only rb

Correlation of map units annotation vzcor

Correlation of map units polygons vzcor

Buried magnetic bodies vzma

Rock unit labels vzlab

Rock unit labels leaders vzlab

Geology arcs vzge

Geology polygons vzge

Guri and southern part of the Tucupita 2¡x3¡ gu.av

quadrangles

Index map, latitude/longitude tics vztc

Index map, annotation index

Index map, lat/long grid only grid

Index map, colored countries, lat/long grid index

Guri, quadrangle lat/long tics gutc

Guri, quadrangle lat/long numbers guout

Guri, quadrangle outline guout

Guri, place name annotation guanno5

Guri, city points guanno5

Guri, roads gurd

Guri, province boundary gupl

Guri, streams annotation gust

Guri, streams gust

Guri, linear feature annotation guft

Guri, linear features guft

Guri, correlation of map units annotation gucor

Guri, correlation of map units polygons gucor

Guri, map key annotation guleg

Guri, map key points gulegpt

Guri, map key arcs guleg

Guri, map key polygons guleg

Guri, scale bar annotation guscale

Guri, scale bar guscale

Guri, rock unit labels gulab

Guri, rock unit labels leaders gulab

Guri, geology arcs guge

Guri, geology polygons guge

Ciudad Piar and part of the Ciudad Bolivar 2¡x3¡ pi.av

quadrangles

Index map, latitude/longitude tics vztc

Index map, annotation index

Index map, lat/long grid only grid

Index map, colored countries, lat/long grid index

Ciudad Piar, quadrangle lat/long tics pitc

Ciudad Piar, quadrangle lat/long numbers piout

Ciudad Piar, quadrangle outline piout

Ciudad Piar, place name annotation pianno5

Ciudad Piar, city points pianno5

Ciudad Piar, roads pird

Ciudad Piar, province boundary pipl

Ciudad Piar, streams annotation pist

Ciudad Piar, streams pist

Ciudad Piar, linear feature annotation pift

Ciudad Piar, linear features pift

Ciudad Piar, structural trends from SLAR pisr

Ciudad Piar, correlation of map units annotation picor

Ciudad Piar, correlation of map units polygons picor

Ciudad Piar, map key annotation pileg

Ciudad Piar, map key points pilegpt

Ciudad Piar, map key arcs pileg

Ciudad Piar, map key polygons pileg

Ciudad Piar, scale bar annotation piscale

Ciudad Piar, scale bar piscale

Ciudad Piar, rock unit labels pilab

Ciudad Piar, rock unit labels leaders pilab

Ciudad Piar, kimberlite area annotation pima

Ciudad Piar, kimberlite area pima

Ciudad Piar, geology arcs pige

Ciudad Piar, geology polygons pige

San Fernando de Apure 2¡x3¡ quadrangle (Bolivar part) sf.av

Index map, latitude/longitude tics vztc

Index map, annotation index

Index map, lat/long grid only grid

Index map, colored countries, lat/long grid index

San Fernando, quadrangle lat/long tics sftc

San Fernando, quadrangle lat/long numbers sfout

San Fernando, quadrangle outline sfout

San Fernando, place name annotation sfanno5

San Fernando, city points sfanno5

San Fernando, province boundary sfpl

San Fernando, streams annotation sfst

San Fernando, streams sfst

San Fernando, linear features sfft

San Fernando, correlation of map units annotation sfcor

San Fernando, correlation of map units polygons sfcor

San Fernando, map key annotation sfleg

San Fernando, map key points sflegpt

San Fernando, map key arcs sfleg

San Fernando, map key polygons sfleg

San Fernando, scale bar annotation sfscale

San Fernando, scale bar sfscale

San Fernando, rock unit labels sflab

San Fernando, rock unit label leaders sflab

San Fernando, geology arcs sfge

San Fernando, geology polygons sfge

Santa Elena 2¡x3¡ quadrangle (Venezuela part) se.av

Index map, latitude/longitude tics vztc

Index map, annotation index

Index map, lat/long grid only grid

Index map, colored countries, lat/long grid index

Santa Elena, quadrangle lat/long tics setc

Santa Elena, quadrangle lat/long numbers seout

Santa Elena, quadrangle outline seout

Santa Elena, place name annotation seanno5

Santa Elena, city points seanno5

Santa Elena, roads serd

Santa Elena, province boundary sepl

Santa Elena, stream annotation sest

Santa Elena, streams sest

Santa Elena, linear feature annotation seft

Santa Elena, linear features seft

Santa Elena, correlation of map units annotation secor

Santa Elena, correlation of map units polygons secor

Santa Elena, map key annotation seleg

Santa Elena, map key points selegpt

Santa Elena, map key arcs seleg

Santa Elena, map key polygons seleg

Santa Elena, scale bar annotation sescale

Santa Elena, scale bar sescale

Santa Elena, rock unit labels selab

Santa Elena, rock unit labels leaders selab

Santa Elena, geology arcs sege

Santa Elena, geology polygons sege

R'o Caura 2¡ by 3¡ quadrangle ca.av

Index map, latitude/longitude tics vztc

Index map, annotation index

Index map, lat/long grid only grid

Index map, colored countries, lat/long grid index

R'o Caura, quadrangle lat/long tics catc

R'o Caura, quadrangle lat/long numbers caout

R'o Caura, quadrangle outline caout

R'o Caura, place name annotation caanno5

R'o Caura, city points caanno5

R'o Caura, province boundary capl

R'o Caura, stream annotation cast

R'o Caura, streams cast

R'o Caura, linear features annotation caft

R'o Caura, linear features caft

R'o Caura, correlation of map units annotation cacor

R'o Caura, correlation of map units polygons cacor

R'o Caura, map key annotation caleg

R'o Caura, map key points calegpt

R'o Caura, map key arcs caleg

R'o Caura, map key magnetics caleg

R'o Caura, map key polygons caleg

R'o Caura, scale bar annotation cascale

R'o Caura, scale bar cascale

R'o Caura, rock unit labels calab

R'o Caura, rock unit labels leaders calab

R'o Caura, buried magnetic bodies cama

R'o Caura, geology arcs cage

R'o Caura, geology polygons cage

Puerto Ayacucho 2¡x3¡ quadrangle (Venezuela part) ay.av

Index map, latitude/longitude tics vztc

Index map, annotation index

Index map, lat/long grid only grid

Index map, colored countries, lat/long grid index

Puerto Ayacucho, quadrangle lat/long tics aytc

Puerto Ayacucho, quadrangle lat/long numbers ayout

Puerto Ayacucho, quadrangle outline ayout

Puerto Ayacucho, place name annotation ayanno5

Puerto Ayacucho, city points ayanno5

Puerto Ayacucho, roads ayrd

Puerto Ayacucho, province boundary aypl

Puerto Ayacucho, streams annotation ayst

Puerto Ayacucho, streams ayst

Puerto Ayacucho, linear features ayft

Puerto Ayacucho, correlation of map units annotation aycor

Puerto Ayacucho, correlation of map units polygons aycor

Puerto Ayacucho, map key annotation ayleg

Puerto Ayacucho, map key points aylegpt

Puerto Ayacucho, map key arcs ayleg

Puerto Ayacucho, map key magnetics ayleg

Puerto Ayacucho, map key polygons ayleg

Puerto Ayacucho, scale bar annotation ayscale

Puerto Ayacucho, scale bar ayscale

Puerto Ayacucho, rock unit labels aylab

Puerto Ayacucho, rock unit labels leaders aylab

Puerto Ayacucho, section line annotation aylabcr

Puerto Ayacucho, section line on map aylabcr

Puerto Ayacucho, section annotation aycrm

Puerto Ayacucho, section leaders aycrm

Puerto Ayacucho, section geology arcs aycrm

Puerto Ayacucho, section geology polygons aycrm

Puerto Ayacucho, buried mag annotation aymalab

Puerto Ayacucho, buried mag leaders aymalab

Puerto Ayacucho, buried magnetic bodies ayma

Puerto Ayacucho, geology arcs ayge

Puerto Ayacucho, geology polygons ayge

La Esmeralda 2¡x3¡ quadrangle (Venezuela part) es.av

Index map, latitude/longitude tics vztc

Index map, annotation index

Index map, lat/long grid only grid

Index map, colored countries, lat/long grid index

La Esmeralda, quadrangle lat/long numbers esout

La Esmeralda, quadrangle outline esout

La Esmeralda, place name annotation esanno5

La Esmeralda, city points esanno5

La Esmeralda, province boundary espl

La Esmeralda, streams annotation esst

La Esmeralda, streams esst

La Esmeralda, linear features esft

La Esmeralda, structural trends from SLAR essr

La Esmeralda, correlation of map units annotation escor

La Esmeralda, correlation of map units polygons escor

La Esmeralda, map key annotation esleg

La Esmeralda, map key points eslegpt

La Esmeralda, map key arcs esleg

La Esmeralda, map key polygons esleg

La Esmeralda, rock unit labels eslab

La Esmeralda, rock unit labels leaders eslab

La Esmeralda, buried magnetic bodies esma

La Esmeralda, geology arcs esge

La Esmeralda, geology polygons esge

Atabapo 2¡x3¡ quadrangle (Venezuela part) at.av

Index map, latitude/longitude tics vztc

Index map, annotation index

Index map, lat/long grid only grid

Index map, colored countries, lat/long grid index

Atabapo, quadrangle lat/long numbers atout

Atabapo, quadrangle outline atout

Atabapo, place name annotation atanno5

Atabapo, swamp symbols atanno5

Atabapo, province boundary atpl

Atabapo, streams annotation atst

Atabapo, streams atst

Atabapo, linear features atft

Atabapo, correlation of map units annotation atcor

Atabapo, correlation of map units polygons atcor

Atabapo, map key annotation atleg

Atabapo, map key arcs atleg

Atabapo, map key magnetics atleg

Atabapo, map key polygons atleg

Atabapo, scale bar annotation atscale

Atabapo, scale bar atscale

Atabapo, rock unit labels atlab

Atabapo, rock unit labels leaders atlab

Atabapo, buried magnetic bodies atma

Atabapo, geology arcs atge

Atabapo, geology polygons atge

R'o Mavaca 2¡x3¡ quadrangle (Venezuela part) ma.av

Index map, latitude/longitude tics vztc

Index map, annotation index

Index map, lat/long grid only grid

Index map, colored countries, lat/long grid index

R'o Mavaca, quadrangle lat/long numbers maout

R'o Mavaca, quadrangle outline maout

R'o Mavaca, place name annotation maanno5

R'o Mavaca, city points maanno5

R'o Mavaca, streams annotation mast

R'o Mavaca, streams mast

R'o Mavaca, linear features maft

R'o Mavaca, correlation of map units annotation macor

R'o Mavaca, correlation of map units polygons macor

R'o Mavaca, map key annotation maleg

R'o Mavaca, map key arcs maleg

R'o Mavaca, map key magnetics maleg

R'o Mavaca, map key polygons maleg

R'o Mavaca, scale bar annotation mascale

R'o Mavaca, scale bar mascale

R'o Mavaca, rock unit labels malab

R'o Mavaca, rock unit labels leaders malab

R'o Mavaca, geology arcs mage

R'o Mavaca, buried magnetic bodies mama

R'o Mavaca, geology polygons mage

Piedra de Cocuy 2¡x3¡ quadrangle (Venezuela part) pc.av

Index map, latitude/longitude tics vztc

Index map, annotation index

Index map, lat/long grid only grid

Index map, colored countries, lat/long grid index

Piedra de Cocuy, quadrangle lat/long numbers pcout

Piedra de Cocuy, quadrangle outline pcout

Piedra de Cocuy, place name annotation pcanno5

Piedra de Cocuy, city points pcanno5

Piedra de Cocuy, province boundary pcpl

Piedra de Cocuy, streams annotation pcst

Piedra de Cocuy, streams pcst

Piedra de Cocuy, linear features pcft

Piedra de Cocuy, structural trends from SLAR pcsr

Piedra de Cocuy, correlation of map units annotation pccor

Piedra de Cocuy, correlation of map units polygons pccor

Piedra de Cocuy, map key annotation pcleg

Piedra de Cocuy, map key points pclegpt

Piedra de Cocuy, map key arcs pcleg

Piedra de Cocuy, map key magnetics pcleg

Piedra de Cocuy, map key polygons pcleg

Piedra de Cocuy, scale bar annotation pcscale

Piedra de Cocuy, scale bar pcscale

Piedra de Cocuy, rock unit labels pclab

Piedra de Cocuy, rock unit labels leaders pclab

Piedra de Cocuy, geology arcs pcge

Piedra de Cocuy, buried magnetic bodies pcma

Piedra de Cocuy, geology polygons pcge

ARCVIEW 3 FILES

The ArcView 1 view for the enitre study area, "vz.av", has been
converted to ArcView 3 format, "vz.apr". It is in "arcunix7/vz"
directory. The coverages are in ARC/INFO 7 format so are useable on Mac,
PC and UNIX platforms.

COVERAGE DATA DEFINITION

GEOLOGY POLYGON ATTRIBUTES:

The ARC/INFO VZGE.PAT file consists of:

COLUMN ITEM NAME WIDTH OUTPUT TYPE INDEXED?

1 AREA 4 12 F

5 PERIMETER 4 12 F

9 VZGE# 4 5 B

13 VZGE-ID 4 5 B

17 FMATN 6 6 C upper-case rock-unit code

23 PTYPEI 3 3 C for sorting units into groups

26 LC 6 6 C mixed-case rock-unit code

32 DESC 60 60 C

92 PTYPES 69 69 C

PTYPEI is a two-digit integer that is used to sort the units into groups
of related rocks. The third character in PTYPEI is a space for
appearance in the legend. PTYPES is composed of PTYPEI, PTYPE, and DESC.
It also can be used to sort correctly by unit group. All the short rock
descriptions are in the INFO file DESC in alphabetical order
(abbreviations: Fm, Formation; gr, grained; Gp Group; E, Early; Prot,
Proterozoic; rx, rocks; Plio, Pliocene; qtz, quartz; Sg, Supergroup;
congl, conglomerate; qtzite, quartzite; Mid, Middle; terr, terrane;
seds, sedimentary rocks; metaseds, metasedimentary rocks):

LC DESC

blank Unmapped area

d Diabase - mafic dikes undivided (Mesozoic to M Proterozoic)

dioritFenitized diorite & tonalite at Cerro Impacto

ic Carbonatite(?) intrusion of Cerro Impacto

Qal Alluvial deposits of sand, gravel, and silt (Quaternary)

QTm Mesa Fm. siltstone and sandy siltstone (Pleistocene & Plio)

water

Xa Amphibolite schist containing andesine (E Prot)

XAgr Granitic rx of Imataca Complex (E Prot and/or Archean)

XAi Imataca Complex orthogneiss and paragneiss (Archean)

XAm Migmatite & gneiss of Imataca Complex (E Prot or Archean)

Xbc Basement complex granite to granodiorite gneiss (E Prot)

Xcb Caballape Fm felsic metatuff and phyllite (E Prot)

Xcc Cicapra Fm (Carichapo Gp) mafic to intermed metatuff E Prot

Xce El Callao Fm (Carichapo Gp) greenstone, greenschist (E Prot

Xcg Granitic rocks of Cuchivero Group (Early Proterozoic)

Xco Cinaruco Fm qtzite, sericitic qtzite, schist (E Prot)

Xcv Caicara Fm (Cuchivero Gp) rhyodacitic-rhyolitic tuff E Prot

Xf1 Felsic metatuff and flows (Early Proterozoic)

Xf2 Felsic metatuff and flows, eugeosynclinal terrane (E Prot)

Xg Calc-alkaline granite & other silicic plutonic rx (E Prot)

Xg1 Metagabbro (greenstone belts) (Early Proterozoic)

Xg2 Metagabbro (eugeosynclinal terrane) (Early Proterozoic)

Xgr Granitic rocks, mostly quartz monzonite (Early Proterozoic)

Xgu Granitic silicic to intermediate intrusive rocks (E Prot)

Xlc Los Caribes Fm arkose, polymict congl, phyllite (E Prot)

Xm1 Meta-mafic to intermediate flow and pyroclastic rx (E Prot)

Xm2 Mafic to intermediate metalava and metatuff (E Proterozoic

Xma Maracapra Fm red beds, felsic volcanics (E Proterozoic)

Xmo Moriche Fm metasedimentary conglomerates (E Prot)

Xmp Intrusive rx of San Carlos metamorphic-plut terrane (E Prot

Xmu Greenstone belt rocks, undivided (Early Proterozoic)

Xpr Pre-Roraima Gp sedimentary rx clay-rich sandstone (E Prot)

Xs1 Schist, phyllite, metatuffs, and metavolcanic rx (E Prot)

Xs2 Muscovite schist and phyllite, eugeosynclinal terr (E Prot)

Xsm Seds and metaseds of uncertain affinity qtz arenite (E Prot

Xsp Supamo Complex sodic granitic rx, paragneiss, etc. (E Prot)

Xu1 Metaperidotite, metapyroxenite, serp & talc schist (E Prot)

Xu2 Ultramafic rx metaperidotite, metapyroxenite, etc. (E Prot)

Xui Ultramafic intrusive rx in La Flor-Carapo area (E Prot)

Xyf Yuruari Fm (Pastora Sg) felsic metatuff (E Prot)

Xys Yuruari Fm Pastora Sg qtz muscovite schist, phyllite E Prot

Ylg Late granite intrusive in, and doming Roraima seds (M Prot)

Yp Parguaza granite, massive, porphryitic & biotite (M Prot)

YXac Alkaline intrusive complexes (Middle to Early Proterozoic)

YXr Roraima Group (undivided) qtz arenite, arkose M &/or E Prot

YXra Auyantepuy Fm (Roraima Gp) quartz arenite, arkose M, E Prot

YXrc Canaima Fm (Roraima Gp) qtz arenite, arkose, etc. M, E Prot

YXrg Guaiquinima Fm (Roraima Gp) qtz arenite, arkose M, E Prot

GEOLOGY ARC TYPES:

The VZGE.AAT items are:

COLUMN ITEM NAME WIDTH OUTPUT TYPE

1 FNODE# 4 5 B

5 TNODE# 4 5 B

9 LPOLY# 4 5 B

13 RPOLY# 4 5 B

17 LENGTH 4 12 F

21 VZGE# 4 5 B

25 VZGE-ID 4 5 B

29 CODE 3 3 I

32 P1 3 3 I

35 P2 3 3 I

CODE DESC

1 international boundary

2 surface water body

30 geological contact

32 geological contact hidden

FAULT ARCS:

The VZFT.AAT attribute table contains:

COLUMN ITEM NAME WIDTH OUTPUT TYPE INDEXED?

1 FNODE# 4 5 B

5 TNODE# 4 5 B

9 LPOLY# 4 5 B

13 RPOLY# 4 5 B

17 LENGTH 4 12 F

21 VZFT# 4 5 B

25 VZFT-ID 4 5 B

29 CODE 3 3 I

32 FTYPEI 3 3 C

35 DESC 60 60 C

95 FTYPES 63 63 C

CODES AND DESCRIPTIONS FOR FAULTS AND OTHER COVERAGES:

The INFO file FTYPE contains:

CODE FTYPEI DESC

20 1 fault

6 2 fault - inferred (dashed)

7 3 fault - implied (dotted)

79 4 thrust fault

127 5 sag fault

17 6 fold axis

21 7 graben

26 8 graben - hidden

25 9 shear zone

72 10 U or Th anomaly

81 11 structural trend

70 12 ring structure

103 13 iron formations

18 14 major magnetic gradient

16 15 fault movement and fold arrows

1 16 international boundary

4 17 province boundary

2 18 surface water body

3 18 tributary

5 19 main road

42 20 secondary road

30 21 geological contact

32 22 geological contact hidden

PERMISSIVE TRACT POLYGONS:

The RA.PAT and RB.PAT polygon attribute files contain:

COL ITEM NAME WDTH OPUT TYP

1 AREA 4 12 F

5 PERIMETER 4 12 F

9 RA# 4 5 B

13 RA-ID 4 5 B

17 FMATN 6 6 C

23 TRACT 5 5 C

28 DESC 64 64 C

92 KEY 69 69 C

TRACT MAP A

KEY

IIa Low-sulfide gold-quartz vein deposits, permissive

IIb Low-sulfide gold-quartz vein deposits, low probability

Ia Algoma iron and sedimentary manganese deposits, permissive

Ib Algoma iron and sedimentary manganese deposits, low probability

VI Tin greisen deposits

VIII Porphyry copper and volcanic-hosted magnetite deposits

TRACT MAP B

KEY

III Kuroko-type massive sulfide deposits

IV Synorogenic-synvolcanic Ni-Cu & related platinum deposits

V Carbonatite deposits and diamond-bearing kimberlite pipes

VII Sedimentary kaolin deposits

MINERAL DEPOSIT POINTS:

The original list of mineral deposits in Bulletin 2062 (USGS and
Corporación Venezolana de Guayana, Técnica Minera, C.A., 1993) was not
available in digital form at the time of publication of this CD-ROM.
Consequently, a new retrieval was made from the USGS Mineral Resources
Data System (Schruben, 1986). This also takes advantage of any updates
that may have taken place in the data base. The retrieval netted 2353
deposits in Venezuela, Guayana, Surinam, French Guinea, and Brazil, of
which 459 deposits fell in the study area. The following fields are
present in the DEPOSIT.PAT file:

COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME

1 AREA 4 12 F 3

5 PERIMETER 4 12 F 3

9 DEPOSIT# 4 5 B -

13 DEPOSIT-ID 4 5 B -

17 RECNO 7 7 C -

24 SITE 40 40 C -

64 CTRY.CODE 2 2 C -

66 STATE 13 13 C -

79 LATITUDE 9 9 C -

88 LONGITUDE 10 10 C -

98 COMMOD_GP 11 11 C -

109 COMMOD 34 34 C -

143 COMMOD1 4 4 C -

147 ORE.MAT 60 60 C -

207 DEP.TYPE 40 40 C -

247 DEP.COMMENTS 80 80 C -

327 MODEL 40 40 C -

367 HOST.RK.NAME 60 60 C -

427 HOST.RK.TYPE 60 60 C -

487 HOST.ROCK.AGE 10 10 C -

497 ASOC.RK.NAME 60 60 C -

557 ASOC.RK.TYPE 60 60 C -

617 ASSOC.ROCK.AGE 10 10 C -

627 ALTERATION 80 80 C -

707 GEOL.COMMENTS 80 80 C -

787 GEN.COMMENTS 80 80 C -

867 REFERENCE 80 80 C -

COMMOD1 is used to assign symbols to the sites for plotting. Please note
that some fields are truncated from the original MRDS information,
particularly the REFERENCE field.

DLG OPTIONAL FORMAT

The DLG format is a U.S. Geological Survey standard for storing
topologically structured files. It results in a compact ASCII file that
is compatible with a variety of graphics software.

The Venezuelan Guayana Shield geology, faults, and correlation chart
have been converted to Digital Line Graph (DLG) Optional format files.
The DLG files contain tagged polygons and arcs. Annotation text is not
supported in the DLG conversion software and is not present in the DLG
files. The DLG file directory follows:

cor.dlg correlation of map units in Equidistant Conic projection

cordd.dlg correlation of map units in decimal degrees

ft.dlg faults in Equidistant Conic projection

ftdd.dlg faults in decimal degrees

ge.dlg geology in Equidistant Conic projection

gedd.dlg geology in decimal degrees

ptype.unl rock unit names, descriptions, colors for Versatec plotter

scale.dlg scale bar in Equidistant Conic projection

scaledd.dlg scale bar in decimal degrees

vzline.unl fault and contact line types

Although the conversion to ARC/INFO is more easily accomplished with
ARC/EXPORT files, which are included elsewhere on this disc, the
following instructions for converting DLG files to ARC/INFO may be
illustrative for converting DLG files to non-ARC/INFO platforms.

These methods for converting DLG files to ARC/INFO coverages have been
adapted from ARC/INFO manuals (Environmental Systems Research Institute,
1990):

1\) Copy the .dlg and .unl files from the CD-ROM. For instance, from a
UNIX prompt, type:

arc

cw vz create arc/info workspace

q

cd vz

cdrom in

cp /pdd/cdrom/datafiles/dlg/\*.unl .

cdrom out

2\) Launch ARC/INFO and create a lookup table for the rock unit codes:

arc

tables

define ptype.lut

Enter Command: define ptype.lut

1

Item Name: major1

Item Width: 6

Item Output Width: 6

Item Type: i

7

Item Name: fmatn

Item Width: 6

Item Output Width: 6

Item Type: c

13

Item Name: ptypei

Item Width: 3

Item Output Width: 3

Item Type: c

16

Item Name: lc

Item Width: 6

Item Output Width: 6

Item Type: c

22

Item Name: color

Item Width: 3

Item Output Width: 3

Item Type: i

25

Item Name: desc

Item Width: 60

Item Output Width: 60

Item Type: c

85

Item Name:

Enter Command: alter fmatn

COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME

7 FMATN 6 6 C -

Item name:

Item output width:

Item type:

Alternate item name: cross

COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME

7 FMATN 6 6 C - CROSS

Enter Command: alter color

COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME

22 COLOR 3 3 I -

Item name:

Item output width:

Item type:

Alternate item name: symbol

COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME

22 COLOR 3 3 I - SYMBOL

Enter Command: get ptype.unl

The geology polygon lookup table should look as follows:

COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME INDEXED?

1 MAJOR1 6 6 I - -

7 FMATN 6 6 C - CROSS -

13 PTYPEI 3 3 C - -

16 LC 6 6 C - -

22 COLOR 3 3 I - SYMBOL -

25 DESC 60 60 C - -

Enter Command: list major1 fmatn ptypei lc color

Record major1 fmatn ptypei lc color

1 1 DEEP deep 0

2 2 BLACK black 1

3 3 POS pos 0

4 4 NEG neg 0

5 5 KIMB Kimb 0

6 6 H2O 1 water 61

7 7 QAL 2 Qal 129

8 8 QTM 3 QTm 4

9 9 YXAC 5 YXac 213

10 10 YLG 6 Ylg 106

11 11 IC 7 ic 72

12 12 YXR 8 YXr 123

13 13 YXRA 9 YXra 123

14 14 YXRG 10 YXrg 123

15 15 YXRC 11 YXrc 123

16 16 XPR 12 Xpr 123

17 17 AC 13 ac 213

18 18 XGU 14 Xgu 188

19 19 XG 15 Xg 247

20 20 XCG 16 Xcg 187

21 21 DIORIT 17 diorit 187

Continue? n

Enter Command: list desc

Record desc

1

2

3

4

5

6

7 Alluvial deposits of sand, gravel, and silt (Quaternary)

8 Mesa Fm. siltstone and sandy siltstone (Pleistocene & Plio)

9 Mesa Fm. siltstone and sandy siltstone (Pleistocene & Plio)

10 Alkaline intrusive complexes (Middle to Early Proterozoic)

11 Intrusive rocks in and doming Roraima seds (Mid Prot)

12 Carbonatite intrusion of Cerro Impacto

13 Roraima Group (undivided) qtz arenite, arkose M &/or E Prot

14 Auyantepui Fm (Roraima Gp) quartz arenite, arkose M, E Prot

15 Canaima Fm (Roraima Gp) qtz arenite, arkose, etc. M, E Prot

16 Guaiquinima Fm (Roraima Gp) qtz arenite, arkose M, E Prot

17 Pre-Roraima Gp sedimentary rx clay-rich sandstone (E Prot)

18 Granitic silicic to intermediate intrusive rocks (E Prot)

19 Calc-alkaline granite & other silicic plutonic rx (E Prot)

20 Grantitc rocks of Cuchivero Group (Early Proterozoic)

21 fenitized diorite & tonalite at Cerro Impacto

Continue? n

3\) Create a lookup table for the faults and contacts.

tables

Enter Command: define vzline.lut

1

Item Name: major1

Item Width: 6

Item Output Width: 6

Item Type: i

7

Item Name: code

Item Width: 3

Item Output Width: 3

Item Type: i

10

Item Name: line

Item Width:

Integer value expected.

Item Width: 3

Item Output Width: 3

Item Type: i

13

Item Name: expl

Item Width: 45

Item Output Width: 45

Item Type: c

58

Item Name:

Enter Command: alter line

COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME

10 LINE 3 3 I -

Item name:

Item output width:

Item type:

Alternate item name: symbol

COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME

10 LINE 3 3 I - SYMBOL

Enter Command: it

COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME INDEXED?

1 MAJOR1 6 6 I - -

7 CODE 3 3 I - -

10 LINE 3 3 I - SYMBOL -

13 EXPL 45 45 C - -

Enter Command: get vzline.unl

43 Records Selected.

Enter Command: list

Record MAJOR1 CODE LINE EXPL

1 1 0 9 MAP BORDER NEAT LINE

2 2 1 109 INTL BORDER LONG & SHORT DASH

3 3 2 4 SURFACE WATER BODIES

4 4 3 111 NAMED TRIBUTARIES - BLUE

5 5 4 120 PROVINCES (STATE BOUNDARIES) WAS 118

6 6 5 41 MAIN ROADS SOLID/OPEN

7 7 6 106 FAULT - DASHED INFERRED UNDER RX

8 8 7 117 FAULT - DOTTED IMPLIED UNDER H20-Q

9 9 8 112 THRUST TEETH ON LEFT

10 10 9 1 SECTION LINE

11 11 10 1 BOXES; SCALE

12 12 11 33 DIRT ROAD

13 13 15 5 MAG DERIVED FAULT

14 14 16 1 LEADERS ARROWS

15 15 17 1 FOLD AXIS

16 16 18 101 MAJOR MAG GRADIENT - DOT

17 17 19 106 FAULT - HIDDEN. WAS GSMAP 32

18 18 20 5 LINEAMENT; FAULT

19 19 21 85 GRABEN HATCH ON RIGHT SIDE OF LINE

20 20 23 86 GRABEN HATCH ON LEFT SIDE OF LINE

21 21 25 5 SHEAR ZONE

22 22 26 87 GRABEN HIDDEN HATCH ON RIGHT

Continue? n

Enter Command: q stop

4\) The dlgarc command creates .pcode and .acode INFO files which are
used to link the .lut tables to the coverage. Some of this linking may
be automatic in non-ARC/INFO conversions. If not, the technique is to
use the common -id field to join the .acode and .pcode files to the
coverage, then use major1 as the common field to link ptype.lut and
vzline.lut to the coverage.

Choose a dlg file to convert - Equidistant Conic (ge.dlg) or Decimal
Degrees (gedd.dlg). The following example is for the Equidistant Conic
coverages:

kill ge all

dlgarc optional ../dlg/ge.dlg ge

build ge

build ge line

/\* join the major1 item from ge.pcode using the -id as key

joinitem ge.pat ge.pcode ge.pat ge-id ge-id

/\* join the unit names, colors and description from ptype.lut using
major1

joinitem ge.pat ptype.lut ge.pat major1 major1

/\* join major1 which contains the line type from ge.acode

joinitem ge.aat ge.acode ge.aat ge-id ge-id

/\* join major1 which contains the contact line type from ge.acode

joinitem ge.aat vzline.lut ge.aat major1 major1

kill ft all

dlgarc optional ../dlg/ft.dlg ft

build ft line

/\* join the major1 item from ft.acode using the -id as key

joinitem ft.aat ft.acode ft.aat ft-id ft-id

/\* join major1 which contains the fault line type from ft.acode

joinitem ft.aat vzline.lut ft.aat major1 major1

kill cor all

dlgarc optional ../dlg/cor.dlg cor

build cor

build cor line

/\* join the major1 item from cor.pcode using the -id as key

joinitem cor.pat cor.pcode cor.pat cor-id cor-id

/\* join the unit names, colors and description from ptype.lut using
major1

joinitem cor.pat ptype.lut cor.pat major1 major1

/\* join major1 which contains the line type from cor.acode

joinitem cor.aat cor.acode cor.aat cor-id cor-id

/\* join major1 which contains the contact line type from cor.acode

joinitem cor.aat vzline.lut cor.aat major1 major1

kill scale all

dlgarc optional ../dlg/scale.dlg scale

build scale line

/\* join the major1 item from scale.acode using the -id as key

joinitem scale.aat scale.acode scale.aat scale-id scale-id

/\* join major1 which contains the fault line type from scale.acode

joinitem scale.aat vzline.lut scale.aat major1 major1

DESCRIPTION OF MAP UNITS

SEDIMENTARY ROCKS

Qal - Alluvial deposits (Quaternary)----Sand, gravel, and silt

QTm - Mesa Formation (Pleistocene and Pliocene)\--Siltstone and sandy

siltstone, generally reddish; massive to laminated. Unconsolidated

gravel and sand in upper part. Called Tm on some earlier maps

YXr - Roraima Group (Middle and (or) Early Proterozoic), undivided---

Compilation of regional ages indicates an age of 1,900--1,500 Ma (Sidder

and Mendoza-S., 1991)

YXra - Auyantepuy Formation----Mainly quartz arenite and minor arkose;

forms steep cliffs and flat-topped mesas. Thickness 300--700 m.

Equivalent to Matau' Formation of Reid and Bisque (1975)

YXrg - Guaiquinima Formation----Fine-grained quartz arenite and arkose
that

are cross stratified; red, green, and greenish-gray jasper

composed of devitrified and silicified ash and small crystals of

quartz and feldspar. Weathers to form flat or gently sloping

topography. Upper part is mostly covered with debris from

overlying Auyantepuy Formation. Several hundreds of meters thick.

Equivalent to all but the lowermost part of the UaimapuŽ

Formation of Reid and Bisque (1975)

YXrc - Canaima Formation----Quartz arenite, arkose, conglomeratic
arenite,

conglomerate, siltstone, and shale. Abundant crossbeds in

arenite and arkose units. Weathers to form cliffs on resistant

arenite, arkose, and conglomerate units and slopes on relatively

nonresistant siltstone, shale, and silty arenite units. About

1,000--2,000 m thick. Equivalent to UairŽn and Kukuen‡n

Formations and lowermost part of UaimapuŽ Formation of Reid and

Bisque (1975)

Xpr - Pre-Roraima Group sedimentary rocks (Early
Proterozoic)----Fine-grained

to very fine grained, clay-rich sandstone, locally containing granule-

size quartz grains. Interbedded with red shale and sandy shale

(Brice--o, 1982)

Xco - Cinaruco Formation (Early Proterozoic)\--Quartzite and sericitic

quartzite and minor amounts of sericite-quartz schist and phyllite,

ferruginous quartzite, and one or more intra-formational quartzite

conglomerates (McCandless, 1962)

Xlc - Los Caribes Formation (Early Proterozoic)\--Weakly metamorphosed

sequence of reddish arkose, polymict conglomerate, and finely laminated

phyllite with minor felsic tuff

Xma - Maracapra Formation (Early Proterozoic)\--Weakly metamorphosed red

beds and felsic volcanic rocks

EUGEOSYNCLINAL TERRANE

Xm2 - Mafic to intermediate metalava and metatuff (Early Proterozoic)\--

Chlorite+epidote±actinolite schist and semischist, and greenstone,

commonly with relict pyroxene phenocrysts. Relict textures suggest that

protoliths were amygdaloidal flows and lithic- and crystal-rich tuffs

Xf2 - Felsic metatuff and flows (Early Proterozoic)\--Quartz+muscovite±

chloritoid semischist with relict phenocrysts of partially resorbed

quartz and broken plagioclase replaced by albite. Groundmass mainly

devitrified glass. Traces of relict lapilli locally abundant

Xs2 - Muscovite schist and phyllite (Early
Proterozoic)\--Quartz+muscovite±

chlorite±chloritoid±ankerite schist and phyllite, and subordinate

quartzite or metachert derived from sedimentary and felsic volcanic

rocks. Ankeritic rocks weather to ferruginous schist and phyllite

MAFIC AND ULTRAMAFIC ROCKS OF

THE EUGEOSYNCLINAL TERRANE

Xg2 - Metagabbro (Early Proterozoic)

Xu2 - Ultramafic rocks (Early Proterozoic)\--Mainly metaperidotite and

metapyroxenite, serpentinite, and talc schist. Cumulus texture locally

preserved

VOLCANIC ROCKS

Xcv - Caicara Formation of the Cuchivero Group (Early Proterozoic)\--

Unmetamorphosed ash-flow tuffs and rhyolitic to dacitic flows and

breccias. A U-Pb age of 1,980 Ma was obtained from ash-flow tuff near

Icabarœ (Brooks and others, in press). Called Xc on some maps

INTRUSIVE ROCKS

d - Diabase (Mesozoic to Early Proterozoic)\--Dark-gray to
greenish-gray,

fine- to coarse-grained diabase of tholeiitic composition. Forms dikes

and sills. K-Ar ages of diabase in region are 210--200 Ma and 1,700--

1,600± 0.8 Ma (Teggin and others, 1985; Sidder and Mendoza, 1991).

In cases where locations were determined from side looking airborne
radar

(SLAR) interpretation or from aeromagnetic data, the map symbol is

crosshatched

Yp - Parguaza Granite (Middle Proterozoic)\--Massive, coarsely
crystalline,

porphyritic granite and biotite granite commonly with rapakivi texture

These rocks have been dated about 1,545 Ma, (zircon age; 1,531±39Ma

(Rb/Sr age) Gaudette and others, 1978). The Parguaza Granite is

reported by Mendoza and others (1977) and Ghosh (1985) to be

unconformably overlain by the Roraima Group, although isotopic dates on

the Parguaza Granite (about 1,545 Ma) are within the possible age span

of the Roraima Group (1,900 to 1,545 Ma)(Ghosh, 1985; Sidder and

Mendoza-S., 1991). These age relations can be explained if the Roraima

Group varies significantly in age within the Guayana Shield; that is,

the Roraima Group may be relatively young (\<1,545 Ma) where it

reportedly (Mendoza and others, 1977; Ghosh, 1985) rests on the Parguaza

Granite but may be older than this in the eastern parts of the Guayana

Shield

Ylg - Late granite typically penetrating through and doming Roraima
Group

sediment (Middle Proterozoic)\--In Ca--o Yagua (lat 3¡25\' N., long
65¡40\'

W.), one body was mapped as coarsely equigranular granodiorite with

pronounced rapakivi texture. In the southern part of the R'o Negro (lat

1¡10\' N., long 66¡50\' W.), a similar body named the Piedra de Cocuy
was

described as a granodiorite with 20 percent biotite, 30 percent quartz,

40 percent feldspar, and 10 percent hornblende (Marcano and others,

written communication, 1991). These rocks are characterized by small,

subrounded, and generally strong magnetic anomalies and are commonly

visible in SLAR imagery

ic - Carbonatite intrusion of Cerro Impacto (Mesozoic to Early

Proterozoic)\--Inferred primarily from geochemistry of the laterite
(which

is enriched in Ta, Nb, Th, Ba, and rare earth elements (REE)) and barite

outcrops and from geophysical interpretation that indicates a magnetite-

rich core. Carbonatite underlies a north-trending ridge that has a thick

lateritic cover in a depression composed of fenitized granodiorite and

tonalite. Age may be as young as 80 Ma (Mendoza and others, 1977) or as

old as 1,800 Ma as inferred from intrusive relationship with the
granitic

rocks of the Cuchivero Group (1,900--1,800 Ma; Sidder and Mendoza-S.,

1991\)

YXac - Alkaline complexes (Middle and Early Proterozoic). Generally

small and rounded to subrounded. The structure 2.5 km in diameter at

La Churuata (3o20\'N, 65o25\'W) intruded the base of the eastern flank

of Cerro Duida, southeast of Cerro Marahuaca, and has a Rb/Sr date of

1,300 Ma (Soares, 1985). Its composition has been described as a

combination of \"saturated syenites, quartz-syenites, nepheline

syenites, and granites\", the latter apparently deriving from

assimilation of the sandstones from the surrounding Roraima

Formation. Aegirine, riebeckite, biotite, zircon, monazite, and

bastnaesite have been identified. This structure has associated U,

Th, REE, Zr, and Sn geochemical anomalies. Another example in the

northeastern corner of La Esmeralda quadrangle (3o50\'N, 63o10\'W), is

coarsely crystalline, (phenocrysts from 1 to 2.5 cm), alkalic, with

apparent flow-banding of the feldspar crystals (Jeff Wynn, U.S.

Geological Survey, written communication, 1991). These rocks are

generally only very weakly magnetic, yet are often visible in the

SLAR imagery.. The examples in Caura quadrangle are inferred to be

similar based on interpretation of aeromagnetic data. Called ac on some

maps

Xg - Calc-alkaline granite and other silicic plutonic rocks (Early

Proterozoic)\--Mart'nez (1991) described these rocks as massive, coarse-

grained, gray, equigranular biotite granites with rapakivi texture

similar to the Parguaza batholith. These granites are seen west and

north of Cerro Duida (lat 4¡00\' N., long 65¡30\' W.) in the Amazonas

Federal Territory. These rocks are weakly to moderately magnetic,

commmonly with east-west to west-northwest trends in the magnetic

anomalies. Pronounced west-northwest-striking lineaments in the SLAR

imagery are characteristic, especially in the Atabapo quadrangle.

XAgr - Granitic rocks intruding the Imataca Complex (Early Proterozoic
and

(or) Archean)\--Mostly quartz monzonite. Age uncertain; may include

granitoids as old as Late Archean as well as granitoids of Early

Proterozoic age equivalent to the Supamo or Cuchivero Groups

XAm - Migmatite and gneiss associated with the Imataca Complex (Early

Proterozoic and (or) Archean)\--Quartz monzonite, migmatite, and
lineated

gneiss

Xcg - Granitic rocks of the Cuchivero Group (Early
Proterozoic)\--Includes

granites of Guaniamito, San Pedro, and Santa Rosal'a intruded into

volcanic rocks of the Caicara Formation. Commonly equigranular to

porphyritic, medium to coarse grained, and locally foliated.

Phenocrysts include orthoclase, microcline, plagioclase, quartz,

biotite, muscovite, and accessory sphene, apatite, zircon, and

hornblende. Rb-Sr isotopic age range of 1,900 to 1,800 Ma (Sidder and

Mendoza-S., 1991)

diorit - Fenitized zone in Xcg at Cerro Impacto----Caused by the
underlying

carbonatite. Indicated by smooth depression on SLAR imagery

Xgu - Intrusive rocks, undivided (Early Proterozoic)\--Underlying water-

inundated plains and jungle in the southeastern Amazonas Federal

Territory. Where seen south and east of San Fernando de Atabapo (lat

3¡45\' N., long 67¡40\' W.), they are described as biotite hornblende

granites and granite gneisses (Marcano and others, 1991). These rocks

are weakly magnetic and have no apparent trend

Xgr - Granitic rocks (Early Proterozoic)\--Mostly quartz monzonite.

Porphyritic, medium to coarse grained, some inclusions of granodiorite.

May include potassic granitoids as old as the Supamo Complex and (or)

granitoids as young as or younger than the Cuchivero Group

Xsp - Supamo Complex (Early Proterozoic)\--Sodic granitic rocks,
paragneiss,

migmatite, granodiorite, and sparse pegmatite. About 2,230 to 2,050 Ma

(Sidder and Mendoza-S., 1991)

GREENSTONE BELT ROCKS OF THE

GUASIPATI-EL CALLAO AREAS

Xcb - Caballape Formation (Early Proterozoic)\--Mainly felsic metatuff
and

phyllite derived from laminated volcaniclastic siltstone and graywacke.

Metatuff contains plagioclase phenocrysts, resorbed phenocrysts of

quartz, wisps of pumice, and minor lithic clasts

Pastora Supergroup (Early Proterozoic)\--Divided into:

Yuruari Formation

Xyf - Felsic metatuff\--Quartz±muscovite±calcite semischist. Contains
relict

quartz and feldspar phenocrysts and traces of lapilli and breccia

clasts. Minor greenstone

Xys - Muscovite schist and phyllite\--Finely laminated quartz+muscovite±

chloritoid±biotite±andalusite±sillimanite schist. Locally contains

volcaniclastic metasandstone and felsic metatuff and breccia

Carichapo Group

Xcc - Cicapra Formation\--Mafic to intermediate metatuff. Mainly albite+

epidote±biotite amphibolite. Relict textures suggest interlayering of

tuff and volcaniclastic sandstone

Xce - El Callao Formation\--Greenstone, greenschist and minor talc
schist

and amphibolite. Relict pillow structure is common. Flows are commonly

intercalated with flow breccias. Fine-grained quartz-hematite rocks in

uppermost part. Minor chert

GREENSTONE BELT ROCKS ELSEWHERE IN THE GUAYANA SHIELD

Xsm - Sedimentary and metasedimentary rocks (Early Proterozoic)\--Rocks
of

uncertain affinity along or near R'o Oris in southeastern Ciudad Piar

quadrangle. Corresponds in part to La Quina Formation of Bellizzia-G.

and others (1976). Hematitic quartz arenite; reddish phyllitic

siltstone; feldspathic arenite; conglomeratic arenite; quartz-sericite

phyllite; red, laminated, fine-grained meta-arenite with graded bedding

and erosional channels

Xma - Maracapra Formation of Bellizzia-G. and others (1976) (Early

Proterozoic)\--Weakly metamorphosed red beds and felsic volcanic rocks

Xmu - Greenstone belt rocks, undivided (Early
Proterozoic)\--Gold-bearing,

greenstone belt rocks are reported in the upper R'o Orinoco headwaters,

La Esmeralda quadrangle. The tremendous magnetic gradients in this area

tend to be sinuous and linear. They resemble gradients of the greenstone

belt rocks in eastern Bol'var State. This terrane is distinguished by
low

to moderate relief in the SLAR imagery

Xa - Amphibolite schist (Early Proterozoic)\--Includes local
coarse-grained

metagabbro

Xf1 - Felsic metatuff and flows (Early Proterozoic)\--

Quartz+muscovite±chlorite semischist with relict phenocrysts of

partially resorbed quartz and broken feldspar

Xm1 - Mafic to intermediate metalava and metatuff (Early Proterozoic)\--

Chlorite+albite+epidote±actinolite schist, semischist, and greenstone,

locally amygdaloidal. Subordinate hornblende hornfels, albite-epidote

amphibolite and minor amphibolite. Minor chert

Xs1 - Schist, phyllite, metatuff, and metavolcanic rocks (Early

Proterozoic)\--Quartz-mica schist; quartz-sericite-chlorite schist;

sericitic meta-arenite; sericitic-chloritic phyllite; rhyolitic,

dacitic, andesitic, and basaltic metatuffs; minor metabasalt and meta-

andesite

Xg1 - Metagabbro (Early Proterozoic)\--Saussuritized and, locally,

amphibolitized metagabbro. Cumulus texture locally preserved

Xu1 - Ultramafic rocks (Early Proterozoic)\--Mainly metaperidotite and

metapyroxenite, serpentinite, and talc schist

Xui - Ultramafic intrusive rocks in La Flor-Carapo area (Early

Proterozoic)\--Medium- to coarse-grained pyroxenite sills; ophitic or

subophitic to cumulate textures; saussuritized plagioclase,

clinopyroxene altered to green hornblende, and sparse olivine

ROCKS OF THE IMATACA PROVINCE

XAi - Imataca Complex (Early Proterozoic and (or)
Archean)\--Amphibolite- to

granulite-facies quartzofeldspathic orthogneiss and paragneiss, commonly

garnet-bearing, and felsic granulite. Minor amounts of intermediate to

mafic orthogneiss, granulite, and charnockite. Metamorphosed iron

formations and ferruginous quartzite are shown by dotted lines on map.

Older than 2,800 Ma, the protolith is probably as old as 3,400 to 3,700

Ma (Sidder and Mendoza-S., 1991)

METAMORPHIC ROCKS

Xmo - Moriche Formation (Early Proterozoic)\--Characterized at its type

locality (Cerro Moriche on the middle R'o Ventuari, lat 4¡40\' N., long

66¡25\' W.) as metasedimentary conglomerates, possible remnants of an

ancestral greenstone belt terrane eroded from the protolith (Ghosh,

1985). These rocks are highly magnetic and commonly follow major

structural lows along the middle and upper R'o Orinoco and R'o Mavaca.

They generally form long, linear bodies, some of which are folded by

regional metamorphic events, and are usually visible in the SLAR imagery

Xmp - Intrusive rocks of the San Carlos metamorphic-plutonic terrane
(Early

Proterozoic)----Covering large parts of the southern Amazonas Federal

Territory. These rocks are named for the type locality at San Carlos de

R'o Negro (lat 1¡50\' N., long 67¡05\'W.) and crop out along most of the

R'o Guain'a and R'o Negro. They are described as granite, granite-

porphyry, granite-gneiss, and augen-gneiss with relatively abundant

pegmatites (Marcano and others, 1991). This terrane is characterized by

strong, sinuous, east-west- to N. 70¡ W.-trending, elongate magnetic

anomalies stacked together

Xbc - Basement complex (Early Proterozoic)---Foliated granite to
granodiorite

gneiss

Linear features:

Contact, dashed where inferred primarily from magnetic data

Fault, dashed where inferred, dotted where implied. Includes lineaments
recognized on SLAR

Fault, transverse, arrows show relative movement where known

Fault, thrust, sawteeth on upper plate

Fault\--Bar and ball on downthrown side; dashed where inferred

Fold axis, anticline, overturned anticline, syncline

Graben bounding fault, tics on downthrown side, dashed where inferred

Major deep penetrating shear zone inferred from geologic mapping and
radar imagery

U or Th anomaly

Linear, curvalinear, to circular structural features recognized on SLAR

Ring structure of unknown origin visible in SLAR\--In some cases may
represent a volcanic caldera

Banded iron formation and quartzite of the Imataca complex

Axis of strong pervasive magnetic gradient\--May represent major hidden
fault or suture; U, upthrown side; D, downthrown side

Water contact

Single line tributary

International boundary

Province boundary

Paved road

Point features:

Outcrop

Unimproved airstrip

Settlement

Bedding

Foliation

Joint, vertical joint

Inclined cleavage

Sinkhole