About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

CSPG Special Publications

Abstract


Geology of the North Atlantic Borderlands — Memoir 7, 1981
Pages 95-117
Precambrian to Modern Framework

Paleogeography, Tectonics and Thermal History of Some Atlantic Margin Sediments

R. Siever, J. L. Hager

Abstract

The burial histories of the Paleozoic sedimentary sequences of two basins on the margins of the North Atlantic, North Wales and eastern New York State, are deduced from a reconstruction of their stratigraphy and succession of sedimentary facies. These histories allow us to infer the length of time at which any specific formation was at a given temperature, that temperature being determined by the geothermal gradient of the time.

The geothermal gradient is deduced from assumptions of heat flow from mantle sources derived from consideration of the paleotectonic history of the two basins. Heat flow values assumed are taken by correspondence with measured values from modern plate tectonic environments. The paleotectonic environments are deduced from the distribution of rock types and structures in the basin as well as general evaluation of the history of the orogenic belts.

The North Wales area is interpreted as a back-arc basin in Cambrian to Silurian time. The eastern New York State area is interpreted to be the landward side of a back-arc basin. Once these deductions are made, geotherms for a given time can be estimated and superimposed on the sedimentation diagram for each basin. Further, we can estimate the stage when specific diagenetic reactions would have taken place. The sediments of the North Wales area are then seen to have been most severely affected by deep burial along high geothermal gradients before and during early stages of the Caledonian Orogeny, and to have been only marginally affected by the Hercynian orogeny. The sediments of eastern New York State were primarily affected by deep burial following the Acadian Orogeny as the Devonian-Carboniferous post-orogenic molasse wedge depressed the crust, and a later stage of heating accompanied Triassic rifting.


Pay-Per-View Purchase Options

The article is available through a document delivery service. Explain these Purchase Options.

Watermarked PDF Document: $14
Open PDF Document: $24