--> Abstract: Frequency of Turbidite Events in Northern Taconic Klippe, by B. Baldwin; #90968 (1977).

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Abstract: Frequency of Turbidite Events in Northern Taconic Klippe

B. Baldwin

A 418-m sequence of black argillite with distal turbidite interbeds is present in north-trending vertical beds on the New York-Vermont border. Here, Poultney River exposes 188.1 m in four glacially polished intervals; thickness of the four covered intervals is estimated from field geometry.

Interbeds are graded and laminated and are a few millimeters to 1 m (4 m maximum) thick. In the intervals 325.5 to 348.4 m and 401.7 to 418.2 m, they are few and thin. They form 27% of the interval from 54.9 to 103.0 m, and 55% of that from 145.7 to 246.3 m. Terrigenous interbeds are mature quartz siltstones and sandstones with zircon and tourmaline. Carbonate interbeds are dolomite with different amounts of quartz; there are a few lenses of dolomite conglomerate and chert breccia. Margins of seven shallow channels indicate that original transport was approximately east or west. A 4-m sandstone, with many clasts of siltstone, quartzite, and dolomite, is the first of several thick sandstones in the 224.6 to 246.3-m interval, probably distal channel deposits of a short-lived submarine f n.

These data strengthen published interpretation that the sequence is a starved-rise assemblage deposited east of a cratonic and platform source. The sequence reportedly spans about 90 m.y. of Early Cambrian through Early Ordovician time. If so, the estimated 325 ± 25 m of argillite had a sedimentation rate of 4 m of solid grains per m.y. (or, at 70% porosity and 30% solid grains, 13 m per m.y.). In the 54.9 to 103.0 m interval, interbed frequency is less than 20 events per meter of argillite, but is 15 to 40 events per meter in the 145.7 to 246.3-m interval. Time between events would average 17,000 to 6,000 years.

AAPG Search and Discovery Article #90968©1977 AAPG-SEPM Annual Convention and Exhibition, Washington, DC