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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 68 (1984)

Issue: 4. (April)

First Page: 449

Last Page: 449

Title: Distribution of Organic Richness in Time and Space: ABSTRACT

Author(s): John M. Armentrout


Distribution of organic facies is related to interaction between productivity and preservation, both the consequence of environmental factors. The environment also controls the amount and type of the organic matter present and its potential to yield hydrocarbons.

A conceptual model for predicting organic richness in time and space is based on predictions of the geographic location of high marine organic productivity by upwelling systems during intervals of optimal preservational potential within transgressive cycles. Whether or not the marine organic matter is in fact preserved in the rock record depends on the spatial relationship of the upwelling system to potential environments of preservation. The problem of preservation is addressed at two levels. The first is whether or not a depositional basin was in the proper geographic position to receive the organic matter during a sediment accumulation cycle, and second, whether or not that organic enriched interval is preserved in the stratigraphic sequence of the basin.

Prediction of basin location is derived from plate tectonic reconstructions. Prediction of productivity is based on paleogeographic and paleoclimatic models. Presence or absence of potentially organic-enriched rock units is evaluated by examination of the stratigraphic record of the basin being studied. Measuring actual levels of organic content of the rocks must be done with sample analysis.

The conceptual model for predicting the temporal and spatial distribution of organic richness derived from marine upwelling systems is simplistic by necessity. It focuses on primary parameters and addresses only a few secondary parameters. Success or failure in making predictions with this model in basins already understood can test the validity of the model and which parameters are most important.

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Copyright 1997 American Association of Petroleum Geologists