--> ABSTRACT: An Investigation of Use of Paleomagnetic Techniques in a Carbonate Terrane--Capitan Reef Complex, Southwestern USA, by Gill Darke; #91022 (1989)

Datapages, Inc.Print this page

An Investigation of Use of Paleomagnetic Techniques in a Carbonate Terrane--Capitan Reef Complex, Southwestern USA

Gill Darke

Paleomagnetic techniques have been used to obtain both qualitative and quantitative data concerning the depositional and diagenetic environments of rocks from the Capitan reef complex (Upper Permian) in the Guadalupe Mountains of west Texas and New Mexico. This area was chosen for study because of the excellent constraints on both sedimentology and age, plus the exposure of back-reef, reef, fore-slope, and basinal rocks.

Oriented samples were collected in a transect from shelf to basin from each major facies belt, incorporating both dolomitized and undolomitized rocks, and analyzed using thermal demagnetization techniques.

Samples are weakly magnetized, and approximately 50% of samples have stable magnetizations. There is a trend of increasing magnetic intensity, susceptibility, and stability from shelf to basin, with the exception of samples from fracture systems. Comparison with the apparent polar wander path for North America indicates that basinal limestones acquired their remanence no later than the Late Jurassic. A significant portion of the magnetic minerals appears to have a diagenetic origin, although there is little evidence for these from petrography. The integration of paleomagnetic and petrographic methods thus allows constraints on the timing of diagenetic events--even, in many places, where carbonates have no obvious iron minerals present.

AAPG Search and Discovery Article #91022©1989 AAPG Annual Convention, April 23-26, 1989, San Antonio, Texas.