Stratigraphy and tectonic significance of lower paleozoic continental marginstrata in Northeastern Washington

Article Abstract:

Lower Paleozoic eugeoclinal rocks lie between autochthonous miogeoclinal strata and outboard volcanic arc terranes in the Kootenay Arc in northeastern Washington and southeastern Britsh Columbia. The eugeoclinal strata, divided into the Covada Group and the Bradeen Hill assemblage, records deposition and tectonic processes on the oceanic side of the lower Paleozoic continental margin. The data shows deposition of continental sediment, intermittent volcanism, local faulting, and starved basin conditions, implying tectonic synchroneity along the outer continental margin during the early Paleozoic.

Washington, Continental margins, Washington (State)

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Geology of the western flank of the coast mountains between Cape Fanshaw andTaku Inlet, Southeastern Alaska

Article Abstract:

The stratigraphy of the Coast Mountains batholith between Cape Fanshaw and Taku Inlet, Southern Alaska is comprised of Jura-Cretaceous rocks of the Gravina belt, pre-Permian to Triassic rocks of theTaku terrane, and mid-Proterozoic to upper paleozoic continental margin assemblages. These assemblages may be part of the Yukon-Tanana terrane, which lies underneath most of Yukon and eastern Alaksa. Gravina belt, Taku and Yukon-Tanana terrane strata lie side-by-side along a mid-Cretaceous thrust fault system comprising the Alexander-Wrangellia terrane inboard margin.

Alaska, Mesozoic Era, Batholiths

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40Ar/39Ar and Nd-Sr isotopic characteristics of mid-Ordovician North American K-Bentonites: a test of early Paleozoic Laurentia-Gondwana interactions

Article Abstract:

The chemical, isotopic and mineralogical characteristics of mid-Ordovician North American K-bentonites were analyzed to determine whether Laurentia and Gondwana were contiguous during the early Paleozoic era. A link between Laurentia and Gondwana may be established if an appropriate source region for the North American K-bentonites is found in South America. A discovery of K-bentonites in the North American Caradocian strata with chemical traits of North American beds also demonstrates such a link.

Gondwana (Geology), Gondwana, Laurasia (Geology), Laurasia

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