Titanium mineral resources of the western U.S.: An update

Abstract

Thirteen deposits or districts in the western U.S. have been examined in which titaniummineral resources have been reported or implied. These deposits are of the following general types (in probable order of importance): 1) Cretaceous shoreline placer deposits, 2) silica-sand deposits of California, 3) fluvial monazite placers of Idaho, 4) anorthositerelated deposits, and 5) clay and bauxite deposits of the northwestern U.S. Relative to previous reports, this one shows some greater and some lesser resources (table 1). In any case, titanium-mineral resources of the western U.S. (west of 103 o longitude) remain modest at world scale except as unconventional (especially perovskite) and by-product (especially porphyry) resources. Some deposits, however, have enhanced value to the titanium explorationist for the geologic relations they illustrate. Among the new conclusions are: a) Loci of Cretaceous shoreline placers form linear patterns, nested as a function of age, that can be traced for thousands of kilometers, permitting focused exploration in whole new mountain ranges. b) Medial hematite-ilmenite solid-solution, which is highly magnetic, is a major carrier of TiO 2 values in the Cretaceous deposits of Wyoming. This phase was previously thought to be relatively rare. c) Regressive shoreline placer deposits in indurated Cretaceous sequences expose intricate facies relations, such as the construction of shoreface sequences by long-shore drift over tidal-channel fill, without much loss of paleogeographic information. d) Due to deep weathering, virtually every Eocene sediment that accumulated in the Ione basin at the foot of the Sierra Nevada has economic value, permitting recovery of altered ilmenite and zircon along with silica, clay, coal, and gold. Ilmenite is most abundant in newly recognized shoreline sands. e) Upper Tertiary fluvial placers of Idaho formed in and filled fault-bounded basins and thus are far more voluminous than deposits in the modern valley system. Previously reported resources are thus far too low. f) Mafic igneous rocks of Proterozoic age near Bagdad, Arizona are of ophiolitic affinity, but contain nelsonitic ilmenite enrichments associated with anorthositic layers.

Importance of titanohematite in detrital remanent magnetizations of strata spanning the Cretaceous‐Paleogene boundary, Hell Creek region, Montana

“…Of the selected studies shown in Murphy, 1962, 1977;Force, 2000;Force et al, 2001] and in uranium-bearing Mesozoic and Cenozoic sandstones within central U.S. and south Texas [Force et al, 2001]. Looking at the ages and distributions of these deposits in concert with those for the Figure 11.…”

Type region of the Ione Formation (Eocene), central California: Stratigraphy, paleogeography, and relation to auriferous gravels

“…Study of the Ione Formation by the second author was prompted by a need to investigate the heavy-mineral potential, said by Gomes andothers (1979, repeated by Force andLynd, 1984) to be considerable, and by a desire to understand the relation between gold and heavy mineral enrichment (Force, 1991). Some results are published separately by Force and Creely (2000).…”

Processus dynamo-métamorphiques de bonification des gîtes de Fe-Ti /

“…However, very few papers describe the enrichment of ilmenite in consolidated placers (Faure, 1978;Coipel and Dimanche, 1981; or studies of metamorphosed placers (Muresan, 2002). Although they can represent considerable resources of titanium, such as american Cretaceous shoreline deposits, no specific criteria have been developed to evaluate the effects of metamorphism on titanium oxide-rich metasediments 2000;, Stanaway, 2005. The Sutton paleoplacers have a range of metamorphic titanium oxide phases, presenting an ideal case study of the effects of metamorphism on hemo-ilmenite grains.…”

“…where the liberated ferrous iron is incorporated into chlorite or magnetite . Although the alteration of about one third of the ilmenite grains predates metamorphism (Hébert and Gauthier, in press), any iron released by that process was probably still present in the rocks as cement and thus remained available during metamorphic processes (Force, , 2000. The destabilization of ferromagnesian silicate minerals in the Sutton sandstones also provided iron along with a considerable amount of magnesium .…”