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Biological Markers In Lower Jurassic Synrift Lacustrine Black Shales, Hartford Basin, Connecticut, U.S.A., Michael A. Kruge, John F. Hubert, Jay F. Akes, Paul E. Meriney

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The East Berlin Formation (Lower Jurassic, Hartford basin, Connecticut, U.S.A.) is distinctive for its six cyclic units of lacustrine black shale and gray mudstone. separated by playa and fluvial redbeds. The black shales arc each about a meter thick and were deposited in subtropical, thermally stratified, oligomictic lakes, the youngest of which (lakes 3 through 6) were large enough to flood most of the basin and attained depths of several tens of meters.

The saturate fractions of solvent extracts of organic-rich black shales from each of the six lakes, collected at fresh roadcuts near East Berlin, arc dominated by extended …

Organic Geochemistry Of A Lower Jurassic Synrift Lacustrine Sequence, Hartford Basin, Connecticut, U.S.A., Michael A. Kruge, John F. Hubert, David F. Bensley, John C. Crelling, R Jay Akes, Paul E. Meriney

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Synrift terrestrial strata of the Lower Jurassic East Berlin Formation (Hartford basin, Connecticut, U.S.A.) record cyclical expansion and contraction of major lakes, six of which were deep enough to develop anoxic bottom waters. We have studied one representative lacustrine sequence in detail, sampling a new roadcut near the village of East Berlin. The section examined is 4 m thick, with a gray siltstone at the base, deposited in shallow water, overlain by an organic-rich black shale (deep water), succeeded in turn by another gray siltstone, deposited as the lake waters gradually receded. The upper gray siltstone is chemically distinct from …