Chemical remagnetization and paleomagnetic dating of fluid migration events: Testing the orogenic fluid hypothesis
- Univ. of Oklahoma, Norman, OK (United States)
Remagnetization, the acquisition of a secondary magnetization, is now recognized as a widespread phenomenon in sedimentary rocks. The recognition that many sedimentary rocks were remagnetized long after deposition has not only led to a reevaluation of the paleomagnetic database, but also has led to a new application of the paleomagnetic method to other areas of earth science. Many secondary magnetizations are tangible evidence of a chemical event caused by rock-fluid interactions. Recent studies demonstrate that isolation of a chemical remanent magnetization (CRM) and comparison of the corresponding pole position to the apparent polar wander path can provide essential constraints on the timing of a diagenetic event. Many CRMs can be spatially correlated with orogenic belts and temporally related to orogeny. In this talk several case studies will be presented where paleomagnetic and geochemical results are used to date diagenetic events and test the role of orogenic fluids as agents of remagnetization. The Ordovician Viola Limestone contains a pervasive Pennsylvanian CRM and a localized Permian CRM that occurs in a halo around veins mineralized by saline radiogenic fluids. The Permian CRM can be related to alteration by the basinal fluids. The pervasive CRM, which is similar to many other CRMs that have been related to orogenic fluids, occurs in relatively unaltered limestone. The acquisition of this CRM was caused by an as yet unidentified chemical mechanism that was not triggered by externally-derived fluids. Preliminary results, however, suggest a connection between the CRM and organic matter in the limestone. Radiogenic Cambrian-Ordovician dolomites near the Ouachita Mountains in southern Oklahoma that have been altered by basinal fluids contain a late Paleozoic CRM. Understanding the origin of these CRMs will require tests of mechanisms that do not rely on externally-derived fluids.
- OSTI ID:
- 5594468
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (United States), Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Vol. 77:11; ISSN 0149-1423; ISSN AABUD2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
020200* -- Petroleum-- Reserves
Geology
& Exploration
AGE ESTIMATION
EXPLORATION
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
GEOLOGY
MAGNETIZATION
MINERAL RESOURCES
OROGENESIS
PETROLEUM DEPOSITS
PETROLEUM GEOLOGY
PLATE TECTONICS
RESERVOIR ROCK
RESOURCES
ROCK-FLUID INTERACTIONS
SEDIMENTARY BASINS
TECTONICS