Contributions to the Geology 

of Mineral Deposits

Exploration for Porphyry Metal Deposits Based on

Rutile Distribution a Test in Sumatera 

Titanium Mineral Resources of the United States 

Definitions and Documentation

GEOLOGICAL SURVEY BULLETIN 1558-A. B

Contributions to the Geology 

of Mineral Deposits

A. Exploration for Porphyry Metal Deposits Based on

Rutile Distribution a Test in Sumatera, by Eric R. 

Force, Sukirno Djaswadi, and Theo van Leeuwen

B. Titanium Mineral Resources of the United StatesDefinitions and Documentation, by Eric R. Force and 

LangtryE. Lynd

GEOLOGICAL SURVEY BULLETIN 1558 - A, B

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1984
DEPARTMENT OF THE INTERIOR 

WILLIAM P. CLARK, Secretary

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director

Library of Congress Cataloging in Publication Data

Force, Eric R.

Exploration for porphyry metal deposits based on rutile distribution a test in Sumatera.

(Contributions to the geology of mineral deposits)

(Geological Survey bulletin; 1558-A-1558-B)

No collective t.p. Titles transcribed from individual title pages.

Includes bibliographies.

Supt. of Docs, no.: I 19.3:1558-A&B

1. Copper ores Tropics. 2. Copper ores Indonesia. 3. Porphyry Tropics. 4. PorphyryIndonesia. 5. Rutile. 6. Titanium ores United States. I. Djaswadi, Sukirno. 

II. Leeuwen, Theo van. III. Lynd, Langtry E. IV. Force, Eric R. Titanium mineral 

resources of the United States definitions and documentation. 1984. V. Title. 

VI. Title: Titanium mineral resources of the United States definitions and 

documentation. VII. Series. VIII. Series: Geological Survey bulletin; 1558-A-1558-B.

QE75.B9 no. 1558-A-1558-B 5573s [622M83] 83-600379

[TN271.C6]

For sale by the Distribution Branch, U.S. Geological Survey, 

604 South Pickett Street, Alexandria, VA 22304
CONTENTS

[Letters designate the chapters]

Page

(A) Exploration for porphyry metal deposits based on rutile distribution 

a test in Sumatera, by Eric R. Force, Sukirno Djaswadi, and Theo 

van Leeuwen.................................................................................................................. Al

(B) Titanium mineral resources of the United States definitions and

documentation, by Eric R. Force and Langtry E. Lynd .................................. Bl

Exploration for Porphyry Metal 

Deposits Based on Rutile Distribution 

a Test in Sumatera

By ERIC R. FORCE, SUKIRNO DJASWADI, and THEO VAN LEEUWEN 

CONTRIBUTIONS TO THE GEOLOGY OF MINERAL DEPOSITS

GEOLOGICAL SURVEY BULLETIN 1558-A

A new exploration tool for porphyry 

deposits in the tropics

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1984

CONTENTS

Page

Abstract ................................................................... Al

Introduction ............................................................... 1

Acknowledgments........................................................ 2

Rutile distribution in porphyries ............................................ 2

Applicability to exploration in the tropics ................................... 2

The Tangse porphyry ....................................................... 3

Sampling methods ......................................................... 6

Laboratory methods ........................................................ 7

Recommended method...................................................... 7

Results of proximal exploration ............................................. 7

Results of distal exploration ................................................ 8

Comparison with other exploration techniques ............................... 8

Conclusion ................................................................. 9

References cited............................................................ 9

ILLUSTRATIONS

Figure 1. Location and regional geologic map ............................... A5

2. Geologic and alteration map of the Tangse prospect showing 

distribution of rutile in proximal soil and stream-sediment 

samples ........................................................ 6

III

CONTRIBUTIONS TO THE GEOLOGY OF MINERAL DEPOSITS

EXPLORATION FOR PORPHYRY METAL

DEPOSITS BASED ON RUTILE 

DISTRIBUTION A TEST IN SUMATERA

By ERIC R. FORCE, 1 SUKIRNO DJASWADI,2

and THEO VAN LEEUWEN3

ABSTRACT

At the Tangse porphyry-copper prospect, rutile in thick soil reflects the distribution 

of the quartz-sericite and biotite-chlorite zones of hydrothermal alteration at depth. 

Detection of rutile in the samples is not simple, but studies of rutile distribution may 

nevertheless be a cheap exploration method for tropical porphyries.

INTRODUCTION

A program of investigation is being undertaken cooperatively by 

the Indonesian Directorate-General of Mines and theU.S. Geological 

Survey (USGS), sponsored by the Government of Indonesia and the 

U.S. Agency for International Development; it includes this study.

Recent work has documented the presence of rutile in the most 

severely altered parts of porphyry alteration systems (Lawrence and 

Savage, 1975; Force, 1976a; Williams and Cesbron, 1977; Force and 

others, 1980; Force, 1980a; Llewellyn and Sullivan, 1980; 

Czamanske and others, 1981). Because this rutile has a related origin 

and similar distribution to the copper mineralization, knowledge of 

rutile distribution should be useful in exploration for porphyry 

copper, as suggested by Lawrence and Savage and by Williams and 

Cesbron. As rutile is resistant to weathering, determination of rutile 

distribution in soil could be an important part of an exploration 

method where porphyry deposits are concealed by thick soils leached 

of copper. We suspect, on the basis of knowledge of rutile occurrence 

summarized by Force (1976b, 1980b), that in the volcanotectonic 

arcs where many of these porphyries occur, the mere presence of

'U.S. Geological Survey.

Directorate of Mineral Resources, Bandung, Indonesia.

8Rio Tinto Indonesia, Jakarta, Indonesia. A1
A2 CONTRIBUTIONS TO GEOLOGY OF MINERAL DEPOSITS

rutile is an indication of porphyry-related alteration in the broad 

sense. This hypothesis needs further checking.

ACKNOWLEDGMENTS

This work would not have been possible without the help of Umar 

Olii of Rio Tinto, Indonesia, P. H. Silitonga of the Directorate of 

Mineral Resources (Indonesia), W. W. Olive, Jr., of the U.S. Geological Survey, and their colleagues.

RUTILE DISTRIBUTION IN PORPHYRIES

Czamanske and others (1981) provide the most comprehensive 

picture so far of the distribution and origin of rutile in porphyries. 

Rutile is a secondary mineral that mimics the distribution of original 

magmatic titanium minerals such as sphene, biotite, and ilmenite. It 

reaches its greatest abundance and grain size in the biotite potassium feldspar alteration zone of porphyries in the Western United 

States. There it averages 0.3 percent or more as crystals, averaging 

about 0.03 by 0.06 mm, locally in mosaics where it forms pseudomorphs of primary, magmatic titanium minerals. In peripheral 

alteration zones, rutile abundance and grain size progressively 

diminish. In some porphyries, the distribution of rutile and of copper 

ore is about the same.

APPLICABILITY TO EXPLORATION IN THE TROPICS

The correspondence of rutile distribution to certain alteration 

zones, coupled with its resistance to weathering in soils, suggests 

that an exploration method for porphyry deposits could be based on 

rutile distribution. In the deeply weathered tropical terranes where 

this approach would be most useful, however, many porphyries are 

of different compositions and have different types of alteration than 

the Western U.S. quartz monzonitic porphyries most intensively 

studied by Czamanske and others. A few data suggest that these 

differences do not detract from the potential usefulness of rutile. 

Lawrence and Savage (1975) and Cox and others (1973)-described 

quartz dioritic porphyries that contain rutile. We find that advanced 

argillic alteration assemblages with andalusite (common except in 

Western United States) contain rutile.

Two types of exploration with rutile distribution seem possible: 

proximal exploration in soils and local streams, and distal exploration in sediments of large streams.
EXPLORATION BASED ON RUTILE DISTRIBUTION A3 

THE TANGSE PORPHYRY

The Tangse porphyry-copper prospect in Aceh province, northern 

Sumatera (fig. 1), has been briefly described by Young and Johari 

(1978), Page and others (1979), and Taylor and van Leeuwen (1980). 

Subsequent geological mapping, geochemical sampling, ground 

magnetics, induced polarization, and diamond drilling (1,600 m) by 

Rio Tinto Indonesia have resulted in a more comprehensive documentation of the deposit.

The prospect area is near the confluence of two major rivers, 

Krung (river) Tangse and Kr. Bale (fig. 2). It forms a topographic 

depression, occupied by alluvial flats and low, flat-topped hills 

within the Barisan Range, a rugged mountain range that runs along 

the entire western edge of the island of Sumatera. Following closely 

the crest of the Barisan Range is a continuous system of axial valleys, 

including the Kr. Tangse valley, which marks the outcrop of the 

main fault line of the Sumateran fault system. This is essentially a 

right lateral fracture system, although gravity faulting is also important (Katili and Hehuwat, 1967; Page and others, 1979). Several 

other occurrences of porphyry copper are found along this fault zone 

farther to the southeast (Taylor and van Leeuwen, 1980).

The topographic morphology of the Tangse area is subdued because the rocks here are strongly fractured and altered. Primary 

copper mineralization is largely confined to an elongated multiphase stock consisting of various quartz diorite and dacite porphyries and having plan dimensions of 6 1/2 km by 2 km (northwest 

part shown in fig. 2). This stock was intruded into a large composite 

pluton of granitic to dioritic composition, which was emplaced in 

a thick sequence of Mesozoic metavolcanic and metasedimentary 

rocks. The long axis of this intrusive complex is alined between two 

.obliquely converging fault zones belonging to the Sumateran fault 

system. A major feature of the Tangse part of the fault system is 

the large mass of serpentinized ultramafic rocks. Numerous dikes 

(mostly postmineralization) cut the intrusive complex and adjacent 

wall rocks. Potassium-argon ages, determined on hornblende or 

biotite from five samples, indicate a middle Eocene age for the 

pluton and a middle to late Miocene age for the mineralized stock 

and late dikes.

Alteration at Tangse is multistage, and telescoping of alteration 

types has taken place. Fracture-controlled phyllic and advanced 

argillic alteration assemblages, the latter characterized by the 

presence of andalusite, have been superimposed on earlier biotite 

alteration, which has affected virtually the entire quartz diorite 

stock. The secondary biotite has also been selectively altered to
A4 CONTRIBUTIONS TO GEOLOGY OF MINERAL DEPOSITS

chlorite throughout the stock, although the conversion is only locally 

complete. An extensive propylitic halo surrounds the strongly altered stock, but otherwise the areal distribution of alteration types 

does not conform to a zonal sequence even though the temporal relations are clear.

Primary sulfide minerals are pyrite, chalcopyrite, and molybdenite, which are present as disseminations among rock-forming 

minerals and in veinlets. Rocks showing only early-stage alteration 

seldom have total sulfide contents of more than 1-2 volume percent; 

rocks affected by late-stage alteration usually have total sulfide 

contents of more than 3 volume percent. Primary copper mineralization is widespread, although generally of low tenor, and is found in 

association with all alteration types, except propylitic alteration. 

The best mineralization is found in fault-controlled zonesof chloritesericite-quartz alteration. Chalcopyrite is nowhere observed at the 

surface owing to strong weathering. Some chalcocite is commonly 

present directly below the oxidation zone over a relatively short 

interval. Zinc and lead form a well-defined geochemical halo to the 

zone of copper-molybdenum mineralization, but gold is absent.

Secondary rutile had already been detected under the microscope in several core and weathered outcrop samples before the 

present study began. It forms both single tiny crystals and massive 

to skeletal finely granular clusters. Some clusters appear to form 

pseudomorphs of former Fe/Ti oxide crystals, but more commonly 

the rutile is intimately associated with masses of chlorite with or 

without secondary biotite; this rutile is probably the byproduct of 

chloritization (and secondary biotitization?) of titaniferous mafic 

minerals, such as magmatic biotite. The common occurrence of 

zircon crystals within the rutile clusters supports this interpretation. Rutile is also commonly present in alteration assemblages that 

contain little or no chlorite (quartz-sericite; quartz-sericite-andalusite). In these associations, it is usually enclosed in sericite masses. 

Whether the rutile survived overprinting of biotite-chlorite alteration by later phyllic and advanced argillic alterations, or whether 

it is directly related to these late hydrothermal processes, has not 

been determined.

Rutile was not observed in unaltered quartz diorite or in postmineral dikes. The propylitic zone has not been studied in detail, 

but the available data from thin-section study suggests that rutile 

is absent in this zone also, even where it overlaps the zone of secondary biotite alteration. Sphene, however, is very common in the 

propylitic zone. Though our knowledge of rutile distribution in unweathered rock is sketchy at Tangse, it is in accord with results of 

Czamanske and others (1981) and of Williams and Cesbron (1977),
EXPLORATION BASED ON RUTILE DISTRIBUTION A5

who studied rutile from a large number of porphyry copper deposits. 

They observed that rutile may be present in the inner fringes of the 

propylitic zone, and is found throughout more intensely altered 

zones, but disappears outward in favor of the local titanium-bearing 

accessory in the host rocks.

i i

0 25 50 KILOMETERS

INDIAN 

OCEAN

DJAWA

INDEX MAP

___E XPLANATION

| | Quaternary sediments

r~J~\ Quaternary volcanic 

ft n rocks

|^Hj Ultramaf ic complexes

i i Tertiary and Mesozoic 

I* x I intrusive rocks

Y/7/A Tertiary to Paleozoic 

V//A undifferentiated rocks

 Tangse porphyry stock

FIGURE 1. Location and regional geologic map (modified from Young 

and Johari, 1978).
A6 CONTRIBUTIONS TO GEOLOGY OF MINERAL DEPOSITS 

SAMPLING METHODS

Soil samples were collected from about the upper meter of exploration trenches. Stream sediments were from large active 

streams upstream and downstream from the deposit and small 

streams within the deposit. We found that most of the rutile was too 

fine to be concentrated in a pan. The best sample proved to be a -80 

mesh screen fraction from which the clay-size material was decanted. Most of these fractions were prepared in the field. Bulk 

samples and +80 mesh pan concentrates were also collected for 

insurance.

[ [ Alluvium

[Z 71 Quartz diorite 

^_ porphyry 

fyy'*'! Granodiorite 

Z^tUi and diorite 

H-f.-v-i Metavolcanic rocks

EXPLANATION 

 Major fault

Inner limit propy4i,tic 

zone, hachures indicate 

altered zone

22 r^ Stream-sediment ^"sample

70 OSoil sample

Main zones phyllic and 

advanced argillic alteration

 Approximate contact

O No rutile 

C Rutile <100 

 Rutile >100

FIGURE 2. Geologic and alteration map of the Tangse prospect showing 

distribution of rutile in proximal soil and stream-sediment samples.
EXPLORATION BASED ON RUTILE DISTRIBUTION A7 

LABORATORY METHODS

The rutile is too fine to be identified with confidence under a 

binocular microscope. In thin sections of weathered rock, we observed that goethite(?) and rutile crystallites were so similar that 

they were difficult to differentiate. Accordingly, we treated samples 

with acid to remove goethite, and examined them in grain mounts in 

oils under a petrographic microscope. Immersion in unheated but 

concentrated hydrochloric acid for 2 hours proved to be the least 

drastic treatment that worked. We identified rutile with condenser 

engaged under a high-power objective, using both plane and crosspolarized light. Some of the rutile was present as inclusions.

Presence or absence of rutile was determined in numbered, but 

otherwise unlabeled, samples by the first and second authors working independently. We examined pan concentrates also, and, though 

some rutile was identified, no information resulted beyond that obtained from -80 mesh fractions.

RECOMMENDED METHOD

A simple but effective method for rutile determination is (1) use 

an aliquot of a sample collected for soil geochemistry; (2) digest it in 

cold hydrochloric acid for 2 hours; (3) rinse, allowing the clay-sized 

material to escape; (4) remove the coarse fraction with an 80-mesh 

screen and dry the fines; (5) identify in grain mount with petrographic microscope, as explained above, and record rutile grain 

size. This should all be possible in a suitably equipped field office.

RESULTS OF PROXIMAL EXPLORATION

Soil samples. The distribution of rutile in soil at Tangse correlates closely with the intensity of alteration of parent rock. Rutile is 

limited to soils over rock that has been altered to quartz-sericite 

(±andalusite) or biotite-chlorite assemblages. All soils over such 

rock contain rutile (fig. 2). In addition, the coarsest rutile is found in 

an axial belt of maximum alteration and sulfide concentration.

We were able to see postmineral dikes in trench bottoms and 

avoided taking soil samples over them. An exploration program 

based on rutile distribution without trench exposures, however, 

would have to allow for postmineral dikes that would yield samples 

without rutile in intensely altered and mineralized areas.

Stream sediments. Three samples of sediments from short 

streams draining the deposit were analyzed (fig. 2). The fact that 

all contained rutile indicated that proximal alluvial sampling as
A8 CONTRIBUTIONS TO GEOLOGY OF MINERAL DEPOSITS

well as soil sampling for rutile could be useful in delineating a porphyry body.

RESULTS OF DISTAL EXPLORATION

Nine sediment samples from the two largest streams were collected; six were downstream of the deposit (most are outside area 

shown on fig. 2). Rutile was not observed in any of these samples. 

Two problems are apparent: (1) Massive dilution with other debris 

has taken place, making rutile hard to find; (2) vigorous winnowing 

has removed most of the fine-grained rutile and transported it to 

lower energy depositional sites downstream. Thus, reconnaissance 

or distal exploration by means of rutile distribution may not be 

useful.

COMPARISON WITH OTHER EXPLORATION 

TECHNIQUES

At Tangse, rutile exploration worked best in proximal samples 

that is, in soil samples and in sediment samples from small streams 

draining the deposit. Thus, exploration based on rutile distribution 

is most appropriately compared with other proximal exploration 

techniques such as soil geochemistry and trenching.

Rutile distribution is consistent with results of soil geochemistry 

at Tangse (Young and Johari, 1978; Page and others, 19.79) but can 

be determined easier and faster. Rutile distribution, like gold distribution, gives information even where other diagnostic elements 

have been leached from tropical soils. Where gold is absent over 

mineralized rock, as it was at Tangse, prospecting with rutile may 

be the only effective surface technique.

Our observations of the rutile in soil collected at the top of soil 

profiles exposed in trenches corresponded well with our observations 

of rock alteration made on weathered samples at the bottom of the 

same trenches. Thus, to some extent, knowledge of rutile distribution 

can make extensive trenching unnecessary.

An integrated technique using soil geochemistry, trenching, and 

rutile distribution should provide more information at about the 

same cost as that for present exploration techniques.

Tangse is the wrong place to test the use of rutile in distal or reconnaissance exploration, as Kr. Tangse and Kr. Bale are powerful 

braided streams carrying immensely more material than is supplied by erosion of the subdued hills underlying the deposit. Our 

initial results were discouraging as were those of stream-sediment 

geochemistry for similar distal exploration. A better test could be 

done where a deposit is nearer a drainage divide.
EXPLORATION BASED ON RUTILE DISTRIBUTION A9 

CONCLUSION

The distribution of rutile in soil over the deeply weathered Tangse 

porphyry is the same as the distribution of intensely altered rock at 

depth. With the methods we have described here, the distribution 

of rutile in soil is not difficult to establish. Thus, rutile studies could 

be a valuable part of comprehensive exploration programs for porphyry deposits in the tropics. Alluvial prospecting for distant porphyries by means of this technique appears to be inefficient in our 

somewhat atypical example. More detailed work and tests over other 

deposits are certainly warranted.

REFERENCES CITED

Cox, D. P., Larson, R. P., and Tripp, R. B., 1973, Hydrothernaal alteration in Puerto

Rican porphyry copper deposits: Economic Geology, v. 68, p. 1329-1344. 

Czamanske, G. K., Force, E. R., and Moore, W. J., 1981, Some geologic and potential

resource aspects of rutile in porphyry copper deposits: Economic Geology, v. 76, p.

2240-2256. 

Force, E. R., 1976a. Titanium minerals in deposits of other minerals: U.S. Geological

Survey Professional Paper 959-F, 10 p. 

__ 1976b, Metamorphic source rocks of titanium placer deposits: a geochemical

cycle: U.S. Geological Survey Professional Paper 959-B, 16 p. 

__ 1980a, Is the U.S. (/coloairdllt/ dependent on imported rutile: 4th Industrial

Minerals International Congress, Atlanta, 1980, p. 43-47.

1980b, The provenance of rutile: Journal of Sedimentary Petrology, v. 50, p.

485-488.

Force, E. R., Czamanske, G. K., and Moore, W. J., 1980, Rutile from porphyry Cu 

deposits [abs.]: American Institute of Mining, Metallurgical and Petroleum Engineers, AIME National Meetings, Las Vegas, Nevada, February 1980, p. 21.

Katili, J., and Hehuwat, F., 1967, On the occurrence of large transcurrent faults on 

Sumatra Indonesia: Osaka, Japan, Osaka City University Journal of Geosciences, 

v. 10, p. 1-17.

Lawrence, L. J., and Savage, E. N., 1975, Mineralogy of the titaniferous porphyry 

copper deposits of Melanesia: Australasian Institute of Mining and Metallurgy 

Proceedings, no. 256, p. 1-14.

Llewellyn, T. 0., and Sullivan, G. V., 1980, Recovery of rutile from a porphyry copper 

tailings sample: U.S. Bureau of Mines Report of Investigations 8462, 18 p.

Page, B. G. N., Bennett, J. D., Cameron, N. R., Bridge, D. McC., Jeffery, D. H., Keats, 

W., and Thaib, J., 1979, A review of the main structural and magmatic features of 

northern Sumatra: Journal of the Geological Society of London, v. 136, p. 569-579.

Taylor, D., and van Leeuwen, Th. M., 1980, Porphyry-type deposits in Southeast Asia, 

hi Ishihara, S., and Takenouchi, S., ed., Granitic magmatism and related mineralization: Mining Geology Special Issue, no. 8, p. 95-116.

Williams, S. A., and Cesbron, F. P., 1977, Rutile and apatite: Useful prospecting 

guides for porphyry copper deposits: Mineralogical Magazine, v. 41, p. 288-292.

Young, R. D., and Johari, S., 1978, The Tangse copper-molybdenum prospect. North 

Sumatra, hi Prinya Nutalaya, ed.. Proceedings 3rd Regional Conference on Geology 

and Mineral Resources of Southeast Asia, Bangkok: Asian Institute of Technology, 

p. 377-386.

Titanium Mineral Resources of the 

United States Definitions and 

Documentation

By ERIC R. FORCE and LANGTRY E. LYND

CONTRIBUTIONS TO THE GEOLOGY OF MINERAL DEPOSITS

GEOLOGICAL SURVEY BULLETIN 1558-B

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1984

CONTENTS

Page

Abstract ................................................................... Bl

Introduction ............................................................... 1

Geology of titanium deposits ................................................ 2

Deposits and procedure ..................................................... 2

Resource documentation .................................................... 3

References cited............................................................ 8

ILLUSTRATION

Page

FIGURE 1. Locations of titanium-mineral resources discussed in this paper .... B4

TABLE

Page

TABLE 1. Identified U.S. resources of separable rutile, altered ilmenite,

ilmenite, and perovskite ........................................ B7

III

CONTRIBUTIONS TO THE GEOLOGY OF MINERAL DEPOSITS

TITANIUM MINERAL RESOURCES OF THE

UNITED STATES DEFINITIONS

AND DOCUMENTATION

By ERIC R. FORCE1 and LANGTRY E. LvND2

ABSTRACT

A somewhat complicated definition of titanium mineral resources that is parallel 

to current industry evaluation practice is applied to all identified U.S. resources. The 

totals of these resources have been published jointly by the U.S. Bureau of Mines and 

the U.S. Geological Survey every year since 1977 without the documentation that this 

article provides. Those totals currently are as follows: rutile and its polymorphs 14.1 x 

106 metric tons contained Ti02 , altered ilmenite 33.5 * 106 tons, Iow-Ti02 ilmenite 

46.8 * 106 tons, and perovskite 20 * 106 tons. The largest contributions to these resources for rutile (56 percent) are made by hydrothermally altered rocks (porphyries), 

for altered ilmenite (97 percent) by shoreline sand bodies, for Iow-Ti02 ilmenite (68 

percent) by gabbro-anorthosite complexes, and for perovskite (100 percent) by 

alkalic igneous complexes. Placer deposits contain 42 percent (by weight; more than 

50 percent by value) of U.S. resources of titanium minerals. Individual placer deposits or districts approach the largest igneous deposits or districts in resource 

magnitude.

INTRODUCTION

This paper defines, documents, and updates our titanium mineralresource figures published by the U.S. Bureau of Mines (Lynd, 1978, 

table 3, and Lynd, 1980, table 3, "derived in consultation with the 

U.S. Geological Survey"). Older compilations are by Klemic and 

others (1973) and Peterson (1966). Location information is given by 

Tooker and Force (1980) and Rogers and Jaster (1962); figure 1 

shows the locations of deposits listed herein.

'U.S. Geological Survey.

2U.S. Bureau of Mines. Bl
B2 CONTRIBUTIONS TO GEOLOGY OF MINERAL DEPOSITS 

GEOLOGY OF TITANIUM DEPOSITS

Economic deposits of titanium minerals occur in several distinct 

geologic settings; these are discussed in some detail in Force and 

others (1976). For the purposes of this paper, we will confine ourselves to observing that the titanium minerals of value are all oxides; 

in order of decreasing economic value these are rutile and its polymorphs, altered ilmenite3 (known also as "leucoxene," arizonite, 

pseudorutile, and so forth), ilmenite, and possibly perovskite. These 

oxides occur in hard-rock deposits, in placer deposits, and in altered 

rock. Hard-rock deposits occur in igneous gabbro-anorthosite complexes (ig of table 1), in igneous alkalic complexes (ia), and in metamorphic aluminosilicate bodies (ma). Placer (p) deposits range from 

unindurated modern deposits to indurated old deposits and include 

shoreline sand bodies (ps), glacial lake delta sands (pg), and fluvial 

deposits (pf). Altered rocks (a) containing titanium oxides include 

those formed by hydrothermal alteration (ah), such as the porphyry 

deposits, and those formed by weathering (aw), such as the saprolite 

deposits.

DEPOSITS AND PROCEDURE

Our compilations of titanium resources list only those that pass 

certain tests, which indicate their economic relevance. These criteria 

follow; they constitute our definition of an identified resource of 

titanium minerals.

Only the titanium oxide minerals rutile and its polymorphs, 

altered ilmenite, ilmenite, and perovskite, which are known or 

thought to have some economic value, are included in these figures. 

Titaniferous magnetite, sphene, and other titanium minerals whose 

economic value has not been demonstrated are not included in thi? 

report except in special circumstances listed below.

Also excluded from resources listed here are titanium mineral? 

of finer grain size than 20 /Ltm (0.02 mm), on the grounds that they 

cannot presently be separated. Where ilmenite is known to be 

present as separable grains intergrown with magnetite, resource? 

of the ilmenite are included. Where inseparable intergrowths of 

magnetite and ilmenite together contain 25 percent or more of 

Ti02 , resource figures are also included on the grounds that this 

material could be smelted into high-Ti02 slag.

We have also used a grade cutoff in calculating resources. Our

^Ilmenite that has been upgraded by oxidation and leaching during weathering, typically to 55-65 percent 

Ti02 compared with 45-50 percent in unaltered ilmenite.
TITANIUM MINERAL RESOURCES OF THE UNITED STATES B3

figures include only deposits containing at least 1 percent ilmenite 

or 0.1 percent rutile or linear combinations thereof in unconsolidated 

deposits or 10 percent ilmenite or perovskite or 1 percent rutile in 

hard rocks. Lower grade resources are included if titanium minerals 

could be produced as byproducts of other minerals already being 

mined in the same deposits; the byproduct resource listed is based 

on recovery for 20 years unless otherwise stated.

Resource figures given in table 1 include reserves (see Lynd, 1978, 

1980, and 1983, for separate reserve listing). Resources of less than 

100,000 metric tons of Ti02 are omitted.

Resources of dipping deposits were calculated to a depth of 50 m, 

unless otherwise stated or unless the references cited have demonstrated resources to another depth.

RESOURCE DOCUMENTATION

The following brief descriptions of titanium mineral deposits are 

keyed to table 1. Some documentation herein consists of reasons why 

resources listed by others have been omitted from our list.

Alabama. Sullivan and Browning (1970) gave figures for recoverability of altered ilmenite from sand and gravel operations, 

mostly in Cretaceous sands. The figure in table 1 is based on 10 years 

of potential recovery.

Alaska. The large resources listed by Klemic and others (1973) 

are believed not to fit the definitions of this report. Most of the Ti02 

in the large mafic igneous deposits and a derived alluvial fan is 

present in magnetite and sphene (Wells and Thorne, 1953), although 

some ilmenite is present (Rossman, 1963; C. L. Sainsbury, written 

commun., 1952). The black sand beach deposits contain Ti(>2 as 

sphene, augite, hornblende, and magnetite in addition to ilmenite 

(Thomas and Berryhill, 1962; Cook, 1969). Tonnage figures for the 

beach deposits are not available.

Arizona. At least three Arizona porphyry copper deposits (San 

Manuel, Bagdad, Ajo) contain rutile. Resource figures are from 

Force (1981) and Czamanske and others (1981). Recoverability of 

the rutile is discussed by Llewellyn and Sullivan (1980) and Sullivan 

and Llewellyn (1981).

A kyanite-quartz rock in Yuma County contains rutile (Marsh 

and Sheridan, 1976). Resource figures are based on an approximate 

average rutile content of 1 percent.

Arkansas. Alkalic igneous rocks in the Magnet Cove district 

contain rutile and its polymorphs (Fryklund and Holbrook, 1950). 

Our resource figures are for the Magnet Cove rutile deposit (E.G. 

Toewe and others, written commun., 1971) and the Christy brookite 

deposit (Reed, 1949).
B4 CONTRIBUTIONS TO GEOLOGY OF MINERAL DEPOSITS
TITANIUM MINERAL RESOURCES OF THE UNITED STATES B5

California Ilmenite-magnetite deposits of the San Gabriel 

Mountains could be upgraded by smelting and are therefore included. The listed resource figure is from an aggregate of sources, 

including Oakeschott (1948).

A silica sand operation at lone discards heavy minerals with 20 

percent altered ilmenite (Gomes and others, 1979, and written 

commun.).

Unpublished work by Force and Sherman Marsh with Scott 

Werschky indicates that andalusite-topaz-rutile rock in the White 

Mountains (Gross and Parwel, 1969) contains an average of 2.5 percent rutile in about 107 metric tons of rock.

Colorado. Alkalic igneous rocks near Powderhorn (Temple 

and Grogan, 1965) contain large disseminated perovskite resources 

(Wall Street Journal, 1976) as veins with magnetite in pyroxenite. 

The average perovskite content of ore is about 8 percent. Elger and 

others (1980) have shown that this perovskite can be used to make 

titanium products.

A topaz-sillimanite gneiss near Evergreen contains rutile (Marsh 

and Sheridan, 1976).

Florida. The aggregate resource figure in table 1 includes deposits at Trail Ridge, Green Cove Springs, and elsewhere, which 

contain altered ilmenite and rutile in elevated beach sands.

Florida phosphate deposits contain titanium minerals, separable 

with difficulty because of fine grain size (Stow, 1968; Lamont and 

others, 1972).

Georgia. Deposits of altered ilmenite in old beach sands of 

Georgia include those near Brunswick, on Cumberland Island, 

and in the Cabin Bluff-Woodbine area.

Silica sand operations near Junction City separate heavy minerals 

containing rutile and altered ilmenite (Force, 1981).

Hawaii The titanium-rich saprolites of Hawaii are believed 

not to be titanium resources as defined here. Titanium is present as 

titanomagnetite and titanomaghemite, which are too low in Ti02, 

and as alteration products too fine to separate (Katsura and others, 

1962; Patterson, 1971).

Idaho. Residual clays on basalt of Latah County average 6.4 percent Ti02 (Hosterman and others, 1960), about half as ilmenite.

The Idaho alluvial placer deposits are far too low in ilmenite conFIGURE 1. Locations of titanium-mineral resources discussed in this paper. Numbers refer to those shown in table 1. Underlined numbers denote rutile resources. 

Where deposits are scattered within a geologic unit, the area of the unit is shaded; 

where data are inadequate, shading may stop at State borders.
B6 CONTRIBUTIONS TO GEOLOGY OF MINERAL DEPOSITS

tent to be listed as resources here. This status could change if monazite mining again becomes economic.

Maryland. A chlorite rock in Harford County (Southwick, 1968) 

averages 1 percent rutile (Herz and Valentine, 1970). We have assumed that rutile extends to a depth of 50 m below the bed of Deer 

Creek.

Minnesota. The Duluth Complex of mafic igneous rocks includes 

numerous bodies that together contain 220 million tons of material 

with 10 Dercent or more of TiOs (Minnesota Division of Minerals, 

1977). About 50 percent of Ti02 is separable as ilmenite (Grout, 

1949-50) that contains as much as 48 percent TiOs. If Duluth nickelcopper ores are mined, as much as 500,000 tons per year of ilmenite 

with about 50 percent Ti02 could become available as a byproduct 

(Iwasaki and others, 1982).

Mississippi. Ship Island, a modern barrier island, contains 

concentrations of Iow-Ti02 ilmenite (Hahn, 1962).

New Jersey. Our resource figure for the Lakehurst district is 

that of Markewicz (1969) adjusted for production. Miocene beach 

deposits (Carter, 1978) there contain altered ilmenite.

Neic Mexico. Indurated Cretaceous shoreline sandstones have 

heavy concentrations containing ilmenite, some of which is altered 

(Houston and Murphy, 1962, 1970). Resources are from Chenowith 

(1957).

New York. The Sanford Lake district contains ilmenite with 46- 

50 percent Ti02 in anorthosite and gabbro (Gross, 1968).

In the Port Leyden area, ilmenite-bearing sands are found in 

Pleistocene glacial lake deltas (Force and others, 1976; Stone and 

Force, 1980). Ilmenite grade is only about 1.5 percent, as mixed 

grains with about 25 percent Ti02. Resources listed are from Port 

Leyden Quadrangle only, as grades elsewhere are unknown.

North Carolina. Yadkin Valley resources are from Broadhurst 

(1955), corrected for production. The deposit is of ilmenite in mafic 

schist.

Other North Carolina resources are given by American Paint 

and Coatings Journal (1977).

Oklahoma. River deposits in the Wichita Mountains contain 

ilmenite with 45 percent Ti02 (Hahn and Fine, 1960; Chase, 1952).

Oregon. The Salem bauxite averages 6.5 percent Ti02, 75 percent of which is recoverable as Iow-Ti02 ilmenite (Corcoran and 

others, 1956; Peterson, 1966).

South Carolina. Hilton Head Island contains altered ilmenite 

in old beach sands (Williams, 1967).

Force and others (1982) documented ilmenite resources in other 

old beach sands near Charleston. Resources listed include "anomaly 

K" of that report, a larger low-grade deposit.
TITANIUM MINERAL RESOURCES OF THE UNITED STATES B7

TABLE 1. Identified U.S. resources of separable, altered ilmenite, ilmenite,

and perorskite

[These figures include reserves. Deposit numbers refer to locations shown on figure 1. Types are a, altered rocks; 

ah, altered rocks formed by hydorthermal alteration; aw, altered rocks formed by weathering; ia, igneous alkalic 

complexes; ig, igneous gabbro-anorthosite complexes;; ma, metamorphic aluminosilicate bodies; p, placer deposits; 

pf, fluvial deposits; pg, glacial lake delta sands; and ps, shoreline sand bodies]

Deposit

No.

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

13.

14.

15.

16.

17.

18.

19.

20.

21.

22.

23.

24.

25.

26.

27.

28.

29.

30.

31.

32.

33.

34.

State and district

or description

Alabama; sand and gravel ......

Arizona; porphyry copper ore . . .

Arizona; Yuma County .........

Arkansas; Magnet Cove ........

California; San Gabriel

Mountains ...................

California; lone placer. .........

California; White Mountain

Colorado; Powderhorn ..........

Colorado; Evergreen ...........

Florida; old beach sand .........

Florida; phosphate .............

Georgia; old beach sand ........

Georgia; silica sand ............

Idaho; Latah County clay .......

Maryland; Harford County

Minnesota; Duluth Complex ....

Mississippi; Ship Island ........

New Jersey; Lakehurst .........

New Mexico; Cretaceous sandstones .......................

New York; Sanford Lake .......

New York; Port Leyden ........

North Carolina; Yadkin Valley .

North Carolina; other ..........

Oklahoma; Wichita Mountains . .

Oregon; Salem bauxite .........

South Carolina; Hilton Head ....

South Carolina; Charleston .....

Tennessee; Cretaceous sand .....

Utah; Bingham ................

Virginia; Roseland-Piney River .

Virginia; Willis Mountains,

kyanite ......................

Washington; Spokane ..........

Wyoming; Laramie Range ......

Wyoming; Cretaceous sandstones

Totals by deposit types .......

Totals by mineral ............

Total, all minerals 114,400

Type

P

ah

ma

ia

ig

Pf

ma

ia

ma

ps

P

ps

P

aw

a

ig

ps

ps

ps

ig

Pg

ig

ps

Pf

aw

PS

ps

ps

ah

ig

ma

aw

ig

ps

ig

ia

ma

P

ps

PS

Pf

a

ah

aw

Thousand

Rutile +

polymorphs

4,000

200

200

300

200

1,100

500

100

700

100

100

1,300

4,000

1,000

300

1,000

200

1,000

100

3,100

700

8,000

14,100

metric tons of contained Ti02

Altered

ilmenite

100

600

9,700

200

2,400

200

10,100

400

300

1,100

8,400

500

32,400

600

33,500

Low-'Ti02

ilmenite

4,800

1,300

10,000

100

700

8,600

6,300

200

3,900

1,800

5,500

400

2,700

500

31,800

1,300

6,300

3,900

3,500

46,800

Perovskite

20,000

20,000

20,000
B8 CONTRIBUTIONS TO GEOLOGY OF MINERAL DEPOSITS

Numerous fluvial monazite placers are too small or too low in 

grade to list as titanium resources.

Tennessee. Resources listed occur as Cretaceous shoreline sands 

(Wilcox, 1971) in several deposits.

Utah. The Bingham porphyry copper deposit contains rutile of 

good purity as probably separable grains (Force, 1981; Czamanske 

and others, 1981).

Virginia. Recent work by Force and Norman Herz is the basis 

for the resource figure used here; it includes all previous published 

work on rutile deposits at the contact of anorthosite and its country 

rocks, disseminated ilmenite near the bases of ferrodiorite sheets 

(now saprolitized), and minor nelsonite (see Force and Herz, 1982, 

for geology). Also included are estimates by the Bureau of Mines of 

ilmenite in hard impure nelsonite at Piney River.

The resource figure for Virginia kyanite deposits is based on 

rutile contents of identified kyanite resources (Force, 1981).

Washington. Excelsior clay of the Spokane area contains an 

average of 7 percent Ti02 (Thorsen, 1966; Hosterman and others, 

1960), about half present as ilmenite.

Wyoming. Laramie Range ilmenite-magnetite deposits in 

anorthosite (Hagner, 1968) contain about 30 million tons of material averaging 20 percent Ti02 (Pinnell and Marsh, 1954). Most 

ilmenite is not separable from magnetite, but their intergrowths 

can be upgraded to form a concentrate suitable for smelting (Back 

and others, 1952). Lower grade deposits are not included in resources 

as defined for this report.

Cretaceous shoreline sands contain concentrations of ilmenite, 

some of which is altered (Houston and Murphy, 1962, 1970). Resources listed are half those shown by Dow and Batty (1961), as much 

of the Ti02 is present as magnetite.

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TITANIUM MINERAL RESOURCES OF THE UNITED STATES B9

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