Origin of the Edwin Clay, Ione, California

Bates, Thomas F.

doi:10.1130/0016-7606(1945)56[1:ooteci]2.0.co;2

Cited by 10 publications

(11 citation statements)

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“…Total exhumation varies geographically, with estimates ranging from roughly 4 km in Nevada [3] to 30 km in the southernmost Sierra Nevada [20][21][22]. Across the geographic area of our study sites (Figure 1), the most pronounced exposures of the BTN are overlain by the "auriferous gravels" [19] in the northern Sierra, marked by outcrops of Eocene Ione Formation as far south as Friant, CA (Figure 1; [2,[23][24][25]). South of Friant the BTN is Even though these outcrops of the BTN span several hundreds of kilometers and the age of the overlying deposits span more than 10 million years, the bedrock exposed at the nonconformity is distinctively characterized by similar indicators of deep chemical weathering.…”

Section: Regional Basal Tertiary Nonconformitymentioning

confidence: 99%

“…South of Friant the BTN is Even though these outcrops of the BTN span several hundreds of kilometers and the age of the overlying deposits span more than 10 million years, the bedrock exposed at the nonconformity is distinctively characterized by similar indicators of deep chemical weathering. In the north, lateritic paleosols at the base of the Ione Formation ( Figure 2) have long been recognized [23,24,[35][36][37]. At the southernmost exposure of the Ione formation, a paleo-Oxisol is exposed at its base, and along the length of the southern Sierra Nevada bedrock pediment, distinctive geomorphic, geochemical, and mineralogic markers of deep chemical weathering are present [1,2,25,38].…”

Section: Regional Basal Tertiary Nonconformitymentioning

confidence: 99%

“…The farthest north of the sites near Ione, California hosts a deep lateritic horizon immediately below the BTN where bedrock lithology is the Jurassic Gopher Ridge volcanics [23,24,37,41]. Across roughly 10 m of bedrock, outcrops of intact metavolcanics grade upward into an increasingly weathered paleosol, marked by meter thick zones of almost complete lateritic replacement of bedrock by fine grained ferruginous material and red/orange mottled vermiform laterite ( Figure 2B,C).…”

Section: Ionementioning

confidence: 99%

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Spatial Patterns of Chemical Weathering at the Basal Tertiary Nonconformity in California from Multispectral and Hyperspectral Optical Remote Sensing

Sousa

2019

Remote Sensing

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Visible through shortwave (VSWIR) spectral reflectance of the geologic units across the basal Tertiary nonconformity (BTN) is characterized at three spatially disparate locations in California. At two of these sites, location-specific spectral endmembers are obtained from AVIRIS imaging spectroscopy and linear spectral mixture models are used to visualize spatial patterns in chemical weathering associated with the BTN. Weathering patterns are found to match well with traditional geologic maps of the BTN at each site, but results show more spatially detailed quantitative geologic information about the spatial variability of chemical weathering near the nonconformity than is possible in a traditional geologic map. Spectral endmembers and unmixing results are also compared across locations. At the two locations with AVIRIS coverage, strong absorptions centered near 2200 nm are observed, consistent with previous geologic publications reporting intense chemical weathering at the BTN. Information loss associated with multispectral sampling of the reflectance continuum is also examined by resampling endmembers from the Maniobra location to mimic the spectral response functions of the WorldView 3, Sentinel-2 and Landsat 8 sensors. Simulated WorldView 3 data most closely approximate the full information content of the AVIRIS observations, resulting in nearly unbiased unmixing results for both endmembers. Mean fraction differences are −0.02 and +0.03 for weathered and unweathered endmembers, respectively. Sentinel-2 and Landsat 8 are unable to distinguish narrow, deep SWIR absorptions from changes in the overall amplitude of the SWIR spectral continuum, resulting in information loss and biased unmixing results. Finally, we characterize a third location using Sentinel-2 observations only. At this site we also find spectrally distinct features associated with several lithologies, providing new information relevant to the mapping of geologic contacts which is neither present in high spatial resolution visible imagery, nor in published geologic mapping. Despite these limitations, the spatial pattern of the Sentinel-2 and Landsat 8 fraction estimates is sufficiently similar to that of the WorldView 3 and AVIRIS fraction estimates to be useful for mapping purposes in cases where hyperspectral data are unavailable.

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Section: Regional Basal Tertiary Nonconformitymentioning

confidence: 99%

Section: Regional Basal Tertiary Nonconformitymentioning

confidence: 99%

Section: Ionementioning

confidence: 99%

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Spatial Patterns of Chemical Weathering at the Basal Tertiary Nonconformity in California from Multispectral and Hyperspectral Optical Remote Sensing

Sousa

2019

Remote Sensing

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“…Previous descriptions of the Ione Formation include Allen (1929), Bates (1945), Pask and Turner (1952), Chapman and Bishop (1975), and Wood and others (1995). Recent geologic maps of the basin are by Bartow and Marchand (e.g., 1979).…”

Section: Ione Basin California By Eric R Force and Scott Creelymentioning

confidence: 99%

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

Force¹,

Creely²

2000

Open-File Report

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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.

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“…Greater mineralization might be found under more favorable structural and stratigraphic conditions than exist at the American lignite mine, such as on the west flank of the field where erosion remnants of the Valley Springs formation directly overlap the coal beds. Bates (1945) shows that this stratigraphic relationship exists in the Edwin clay mine about 4 miles west of lone. At this locality, however, the lignite could not be examined because the mine workings were caved and inaccessible.…”

Section: Californiamentioning

confidence: 99%