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An Invertebrate Assemblage From the "Modelo" Formation of Reynier Canyon, Los Angeles, California. Geology and Origin of Talc Deposits of Eastern California

Citation

Wright, Lauren Albert (1951) An Invertebrate Assemblage From the "Modelo" Formation of Reynier Canyon, Los Angeles, California. Geology and Origin of Talc Deposits of Eastern California. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/H7M7-2216. https://resolver.caltech.edu/CaltechETD:etd-08062008-104016

Abstract

An Invertebrate Assemblage From the "Modelo" Formation of Reynier Canyon, Los Angeles, California:

An upper Miocene marine molluscan fauna occurs in basal "Modelo" sandstones that flank Reynier Canyon of the southeastern portion of the Ventura basin, Los Angeles County, California. Here two outliers of these beds are nonconformable on continental siltstones and tuffs of the Mint Canyon formation. The "Modelo" sandstones grade upward into punky diatomaceous shales also of the "Modelo" sequence, that contain Anadara cf. obispoana and a foraminiferal fauna reported to be Mohnian in age. The shales of one outlier are unconformably overlain by other marine sediments.

The upper Miocene age of the basal "Modelo" beds is indicated by the presence of Clementia cf. martini, Dosinia arnoldi, Lyropecten estrellanus ss., Spisula albaria, Tivela diabloensis, and a large Ostrea. Approximately half of the forms in the Reynier Canyon "Modelo" fauna also occur in the Elamere Canyon fauna; these include Laevicardium centifilosum, L. quadragenarium var. fernandoense, Lucina nuttallii, Cancellaria elsmerensis, C. hemphilli, C. tritonidea, Surculites remondii, Murithais eldridgei, Nuculana taphria, and Turritella cooperi. The Elmsmere Canyon species Patinopecten lohri, Astrodapsis fernandoensis, and Dendraster sp. are missing from the "Modelo" fauna.

Geology and Origin of Talc Deposits of Eastern California:

A 200-mile northwest-trending belt in eastern California contains more than 100 talc-bearing localities. The belt is divisible into three districts; each with talc deposits in a distinctive terrane.

In the southernmost district, near Silver Lake, tremolitic talc deposits have formed in highly metamorphosed Archean (?) sedimentary rocks extensively invaded by lamprophyre and granitic rocks. The development of talc-tremolite rock probably involved the extensive introduction of MgO and SiO2 to silica poor dolomite in a complex, multistage history. The MgO may have been released in the granitization of high-magnesian sediments.

In the Southern Death Valley-Kingston Range region tremolitic talc deposits occur at or near the borders of a diabase sill intruded near the base of the lowermost carbonate unit in the Algonkian Pahrump series. The deposits have generally altered from dolomite, both siliceous and silica-poor. Other alteration rocks rich in alkali feldspar are associated with the talc deposits and border diabase bodies higher in the member. MgO and SiO2 have been introduced to form the talc bodies; SiO2, Al2O3, K2O, and probably Na2O to form the feldspathic rocks. Diabase magma was probably the source of most of the additive material, but some may have been derived from connate water.

In the Inyo Range area tremolite-poor talc deposits have formed as alterations of Paleozoic dolomite and quartzite, and of Mesozoic granitic intrusives. The White Eagle deposit shows all three types of alteration, but has formed largely as a replacement of adamellite. Feldspars, quartz and ferromagnesian minerals were decomposed; the talc alteration followed an advance wave of albitization. The additive MgO probably was leached from dolomites at depth.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Petrology and Invertebrate Paleontology
Degree Grantor:California Institute of Technology
Division:Geological and Planetary Sciences
Major Option:Geology
Minor Option:Paleontology
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Popenoe, Willis Parkison (advisor)
  • Campbell, Ian (advisor)
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1951
Additional Information:Thesis title varies in the 1951 Commencement Program: "I. Geology and Origin of Talc Deposits of Eastern California . II. An Invertebrate Assemblage from the "Modelo" Formation of Reynier Canyon, Los Angeles County, California". Supplemental Files Information: Silver Lake talc area, San Bernardino County, California – Main map, sheet one: Supplement 1 from "An invertebrate assemblage from the "Modelo" formation of Reynier Canyon, Los Angeles, California. Geology and origin of talc deposits of eastern California" (Thesis) Date(s) Collected: 1947/1948. Silver Lake talc area, San Bernardino County, California – Main map, sheet two: Supplement 2 from "An invertebrate assemblage from the "Modelo" formation of Reynier Canyon, Los Angeles, California. Geology and origin of talc deposits of eastern California" (Thesis) Date(s) Collected: 1947/1948. Silver Lake talc area, San Bernardino County, California – Main map, sheet three: Supplement 3 from "An invertebrate assemblage from the "Modelo" formation of Reynier Canyon, Los Angeles, California. Geology and origin of talc deposits of eastern California" (Thesis) Date(s) Collected: 1947/1948. Western talc deposit, San Bernardino County, California: Supplement 4 from "An invertebrate assemblage from the "Modelo" formation of Reynier Canyon, Los Angeles, California. Geology and origin of talc deposits of eastern California" (Thesis). Superior and White Cap talc deposits, San Bernardino County, California: Supplement 5 from "An invertebrate assemblage from the "Modelo" formation of Reynier Canyon, Los Angeles, California. Geology and origin of talc deposits of eastern California" (Thesis) Date(s) Collected: 1948/1949. Geologic map of the White Eagle Mine, Inyo County, California: Supplement 6 from "An invertebrate assemblage from the "Modelo" formation of Reynier Canyon, Los Angeles, California. Geology and origin of talc deposits of eastern California" (Thesis).
Record Number:CaltechETD:etd-08062008-104016
Persistent URL:https://resolver.caltech.edu/CaltechETD:etd-08062008-104016
DOI:10.7907/H7M7-2216
Related URLs:
URLURL TypeDescription
https://doi.org/10.22002/D1.466DOISupplement 1 in CaltechDATA: Silver Lake talc area, San Bernardino County, California – Main map, sheet one
https://doi.org/10.22002/D1.467DOISupplement 2 in CaltechDATA: Silver Lake talc area, San Bernardino County, California – Main map, sheet two
https://doi.org/10.22002/D1.468DOISupplement 3 in CaltechDATA: Silver Lake talc area, San Bernardino County, California – Main map, sheet three
https://doi.org/10.22002/D1.469DOISupplement 4 in CaltechDATA: Western talc deposit, San Bernardino County, California
https://doi.org/10.22002/D1.470DOISupplement 5 in CaltechDATA: Superior and White Cap talc deposits, San Bernardino County, California
https://doi.org/10.22002/D1.471DOISupplement 6 in CaltechDATA: Geologic map of the White Eagle Mine, Inyo County, California
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:3031
Collection:CaltechTHESIS
Deposited By: Imported from ETD-db
Deposited On:07 Aug 2008
Last Modified:20 Dec 2019 20:02

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