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Architecture of a transgressive systems tract

Conference ·
OSTI ID:6131492

Coniacian-age marginal marine strata in the San Juan basin illustrate well the three-dimensional architecture of the transgressive component of a third-order depositional sequence. The predictive potential of the model presented here lies in its ability to relate marine, shale-enclosed reservoir sand bodies, in themselves below seismic resolution, to the depositional sequence boundary and condensed section, which normally are very distinct seismic stratigraphic markers. A sequence boundary is identified at the erosional base of the seaward units of the Tocito Sandstone by (1) a hiatus spanning three Inoceramus faunal zones, (2) basal onlap in the sequence above the hiatus as mapped in a pattern of progressively farther landward extent of younger bentonites, and (3) abrupt shallowing of facies across the hiatus. Traced up the depositional dip, the sequence boundary continues beneath a coarse fluvial sandstone (Torrivio sandstone) as demonstrated by incision of this unit into an underlying strand plain, the Gallup Sandstone.

OSTI ID:
6131492
Report Number(s):
CONF-880301-
Country of Publication:
United States
Language:
English