Unknown
PANGAEA
In:
Supplement to: Testarmata, Margaret M; Gose, Wulf A (1984): Magnetic viscosity and paleomagnetism of the basement complex at Catoche Knoll, Deep Sea Drilling Project Hole 538A, Leg 77, southeastern Gulf of Mexico. In: Buffler, RT; Schlager, W; et al. (eds.), Initial Reports of the Deep Sea Drilling Project, Washington (U.S. Govt. Printing Office), 77, 507-514, https://doi.org/10.2973/dsdp.proc.77.117.1984
Publication Date:
2023-06-27
Description:
The basement at Catoche Knoll consists of Paleozoic gneiss and amphibolite intruded by several generations of early Jurassic diabase dikes. Upon exposure to a 1-oersted field for 9 days, the diabase and amphibolite acquire a viscous remanent magnetization (VRM) which ranges from 42 to 2047% of their natural remanent magnetization (NRM). A magnetic field of similar intensity is observed in the paleomagnetic facility of the Glomar Challenger, and it is therefore doubtful if accurate measurements of magnetic moments in such rocks can be made on board unless the facility is magnetically shielded. The significant VRM also indicates the futility of attempting to discern magnetic lineations from an ocean floor composed of such rocks. No strong correlation exists between the Königsberger ratio, which is usually less than 1, and the tendency to acquire a VRM. The VRM decay is typical of a Richter aftereffect, but the relaxation times vary widely among the samples studied. A stable remanence is observed after alternating field demagnetization to 200 Oe. The range of magnetic inclinations in the diabase dikes is consistent with 40Ar/39Ar dates of 190 and 160 Ma. The inclinations suggest that the Catoche Knoll block tilted more than 20° to the north after the final dike intrusion.
Keywords:
77-538A; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; Glomar Challenger; Gulf of Mexico/KNOLL; Leg77
Type:
Dataset
Format:
application/zip, 4 datasets
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