Ash flows and related volcanic rocks associated with the Creede Caldera, San Juan Mountains, Colorado

Ratte, James C.; Steven, Thomas A.

doi:10.3133/pp524h

Cited by 52 publications

(72 citation statements)

References 7 publications

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“…In our case, some samples are typically high in K 2 O and low in Na 2 O because of alkali exchange (e.g., Lipman 1964); this behavior, reflecting a reasonable potassium metasomatism (e.g., Ratté and Steven 1967;Sweetkind et al 1993), may be related to preweathering K enrichment within source terranes (e.g., Fedo et al 1995). As a consequence, the CIA should correctly detect the degree of weathering in source areas.…”

Section: Paleoweathering Sorting and Recycling Processesmentioning

confidence: 99%

Compositional and Geochemical Signatures for the Sedimentary Evolution of the Middle Triassic–Lower Jurassic Continental Redbeds from Western-Central Mediterranean Alpine Chains

Critelli¹,

Mongelli²,

Perri³

et al. 2008

The Journal of Geology

100

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A B S T R A C TCompositional and chemical analyses suggest that Middle Triassic-Lower Liassic continental redbeds (in the internal domains of the Betic, Maghrebian, and Apenninic chains) can be considered a regional lithosome marking the TriassicJurassic rift-valley stage of Tethyan rifting, which led to the Pangaea breakup and subsequent development of a mosaic of plates and microplates. Sandstones are quartzose to quartzolithic and represent a provenance of continental block and recycled orogen, made up mainly of Paleozoic metasedimentary rocks similar to those underlying the redbeds. Mudrocks display K enrichments; intense paleoweathering under a hot, episodically humid climate with a prolonged dry season; and sediment recycling. Redbeds experienced temperatures in the range of 100°-160°C and lithostatic/ tectonic loading of more than 4 km. These redbeds represent an important stratigraphic signature to reconstruct a continental block (Mesomediterranean Microplate) that separated different realms of the western Tethys from MiddleLate Jurassic to Miocene, when it was completely involved in Alpine orogenesis.

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Section: Paleoweathering Sorting and Recycling Processesmentioning

confidence: 99%

Compositional and Geochemical Signatures for the Sedimentary Evolution of the Middle Triassic–Lower Jurassic Continental Redbeds from Western-Central Mediterranean Alpine Chains

Critelli¹,

Mongelli²,

Perri³

et al. 2008

The Journal of Geology

100

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“…Clearly, Lake Creede was influenced by a complex interplay among the tectonic and volcanic history of the region and local climatic, geochemical and hydrological conditions (Finkelstein et al 1999, Larsen & Smith 1999. Wolfe & Schorn (1989) accepted a radiometric date of 27.2 (Ratte & Steven 1967; correction made for recent decay constants), placing the formation in the late Oligocene.…”

Section: Late Eoceneearly Oligocene In the Rocky Mountainsmentioning

confidence: 99%

Floristic composition and comparison of middle Eocene to late Eocene and Oligocene floras in North America

DeVore¹,

Pigg²

2010

Bull. Geosci.

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In comparison to the early and middle Eocene, the late Eocene and particularly the Oligocene floral record is sparse in North America. Changing tectonic, environmental and climatic conditions during these times resulted in the development of fewer depositional systems favorable for fossil preservation. Floras are known from the Southeast, the Pacific Northwest and the Rocky Mountains. Each area has a distinct geological history that shaped both the vegetation adjacent to sites of deposition as well as the depositional environments themselves. The floristic change from middle to late Eocene, and then to Oligocene reflects a changing paleoclimate from the thermal maximum to cooler and drier conditions in the late Paleogene. In the present paper, major middle, and then late Eocene and finally Oligocene floras of North America are summarized, with an emphasis on their regional geology, depositional setting, paleoclimate and significant floral elements. The North American occurrences of coryphoid palms (Sabal) and cycads are reviewed in relationship to their biogeographic history. Finally, we suggest several directions for future research that will further illuminate the floristic changes from middle, to late Eocene and Oligocene that occurred in North America.•

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“…Samples usually are described as partly welded, moderately welded, or densely welded. Because of the direct relationship between porosity and the degree of welding, Ratte and Steven (1967) suggested that a numerical value of porosity would more effectively express the degree of welding than the undefined terms listed above. They would classify rocks having less than 10 percent porosity as densely welded and those having more than 10 percent as partly welded.…”

Section: Characteristics Of Surface Exposuresmentioning

confidence: 99%

Geohydrology of the eastern part of Pahute Mesa, Nevada Test Site, Nye County, Nevada

Blankennagel¹,

Weir²

1973

Professional Paper

163

310

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Ash flows and related volcanic rocks associated with the Creede Caldera, San Juan Mountains, Colorado

Cited by 52 publications

References 7 publications

Compositional and Geochemical Signatures for the Sedimentary Evolution of the Middle Triassic–Lower Jurassic Continental Redbeds from Western-Central Mediterranean Alpine Chains

Compositional and Geochemical Signatures for the Sedimentary Evolution of the Middle Triassic–Lower Jurassic Continental Redbeds from Western-Central Mediterranean Alpine Chains

Floristic composition and comparison of middle Eocene to late Eocene and Oligocene floras in North America

Geohydrology of the eastern part of Pahute Mesa, Nevada Test Site, Nye County, Nevada

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