Diagenetic framework for chemical remanence acquisition in lower Paleozoic carbonate rocks from W. Newfoundland
- Univ. of Houston, TX (United States)
The Lower Ordovician (Tremadocian) St. George Group on Port au Port Peninsula forms part of the Cambro-Ordovician autochthonous carbonate sequences of W. Newfoundland. The geology and stratigraphy of the St. George Group indicates that these rocks have been subjected to distinct uplift and exposure events and their petrographic characteristics suggest a complex diagenetic history. Paleomagnetic, petrographic, geochemical, and geological evidence will be presented that indicates both Paleozoic components record chemical remanent magnetizations associated with subaerial exposures of the ancient continental shelf during at least two distinct times in the Paleozoic. Given the observed range of petrographic and magnetic variability, it appears that during the (Early-Middle ) Ordovician, the lower St. George rocks underwent relatively rapid diagenesis, including lithification, calcite cementation, sulfide precipitation, dolomitization, dedolomitization, and hematite authigenesis. The Late Paleozoic component appears to represent a remagnetization component also associated with dedolomitization and hematite authigenesis and cementation. Perhaps more important, rock samples bearing hematite as the major remanence phase can be petrographically identical to one another, yet carry distinct directional components acquired at different times in geologic history.
- OSTI ID:
- 5862895
- Report Number(s):
- CONF-910403--
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (United States), Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Vol. 75:3; ISSN AABUD; ISSN 0149-1423
- Country of Publication:
- United States
- Language:
- English
Similar Records
Limestones of western Newfoundland that magnetized before Devonian folding but after Middle Ordovician lithification
Algal origin of peloids, peloidal intraclasts, and structure grumeleuse in Paleozoic limestones: evidence from Cow Head group, western Newfoundland
Related Subjects
580000* -- Geosciences
CANADA
CARBONATE ROCKS
CHEMISTRY
DEVELOPED COUNTRIES
DIAGENESIS
GEOCHEMISTRY
GEOLOGIC AGES
GEOLOGIC FORMATIONS
GEOLOGIC HISTORY
GEOLOGY
HEMATITE
IRON ORES
ISLANDS
MAGNETISM
MAGNETITE
MINERALS
NEWFOUNDLAND
NORTH AMERICA
ORDOVICIAN PERIOD
ORES
OXIDE MINERALS
PALEOMAGNETISM
PALEOZOIC ERA
PETROGRAPHY
ROCKS
SEDIMENTARY ROCKS
STRATIGRAPHY