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Brown, Alton A.1
(1) Consultant, Richardson, TX

ABSTRACT: Estimating Paleo Heat Flow in Cratonic and Foreland Basins: a Proposed Methodology with Application to the Delaware Basin Area, West Texas and New Mexico

Modern heat flow data provide insights for estimating ancient heat flow where other approaches are unsatisfactory. First, heat flow increases toward modern continent-continent collisions (except in adjacent foreland basins). Elevated heat flow is probably related to lithosphere thinning extending beyond the current collision zone. Second, average modern heat flow decreases with increasing time since the last crust heating. Phanerozoic heat flow changes are consistent with lithosphere cooling and thickening.
The following work flow was used to interpret Delaware basin paleo heat flow. Modeled tectonic subsidence of the Ordovician to Carboniferous section indicates subsidence related to Late Cambrian extension. The beta factor was estimated from tectonic subsidence and used to calculate heat flow during this time. Elevated heat flow caused by Marathon collision was estimated from distance to collision front using modern calibration. Heat flow from Early Permian collision until today was estimated using the modern relation between heat flow and heating age, with adjustment for residual effects of the collision heating in the current heat flow.
Modern Eastern Delaware basin heat flow is insufficient to account for observed thermal maturity, even accounting for reasonable Cretaceous deposition and erosion. Heat flow modeled using the approach suggested here causes modern thermal maturity patterns similar to those observed in the western Midland basin, Eastern Delaware basin, and Central Basin Uplift. Heating from Cenozoic volcanics is needed to match anomalously high thermal maturity in the western Delaware basin.

 

AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.