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Title: Magnetic and chemical variations of Mesozoic diabase dikes from eastern North America: evidence for a hotspot in the Carolinas

Abstract

Tholeiitic diabase dikes of Late Triassic and Early Jurassic age occur in swarms throughout the Appalachians. The intrusions exhibit regional variations in magnetic and chemical parameters. Aeromagnetic and ground-magnetic anomalies are highest over dikes in the Carolinas. High amplitude is due primarily to a stronger magnetization (the induced component dominates and is nearly constant within individual intrusions). Effects of host-rock magnetization, thermoremanence, and dike width, attitude, and orientation are insignificant. Chemically the Carolinas dikes are characterized by higher mean values for total iron and relatively low TiO/sub 2/ content. The magnetic and chemical patterns are reminiscent of those found for tholeiitic complexes over oceanic hotspots (Galapagos, Iceland), and suggest that the Carolinas may have been the site of such a feature in Late Triassic--Early Jurassic time. Crustal arching, rifting, and volcanism probably origniated in the Carolinas. Tectonic-volcanic activity gradually migrated northeast (and possibly, southwest) along the Appalachian axis with enlargement of the crustal bulge. In Jurassic time, spreading began farther east; the crustal stress configuration changed, and the tectonic pattern was dominated by the formation of new sets of tensional fractures and sinistral slip along pre-existing faults.

Authors:
;
Publication Date:
Research Org.:
Wesleyan Univ., Middletown, CT
OSTI Identifier:
6204332
Resource Type:
Journal Article
Journal Name:
Geol. Soc. Am., Bull.; (United States)
Additional Journal Information:
Journal Volume: 90:2
Country of Publication:
United States
Language:
English
Subject:
15 GEOTHERMAL ENERGY; NORTH CAROLINA; GEOLOGY; HOT SPOTS; MAGNETIC SURVEYS; SOUTH CAROLINA; GEOCHEMISTRY; IRON; MINERALOGY; TITANIUM OXIDES; CHALCOGENIDES; CHEMISTRY; ELEMENTS; GEOPHYSICAL SURVEYS; METALS; NORTH AMERICA; OXIDES; OXYGEN COMPOUNDS; SOUTHEAST REGION; TITANIUM COMPOUNDS; TRANSITION ELEMENT COMPOUNDS; TRANSITION ELEMENTS; USA; 150201* - Geology & Hydrology of Geothermal Systems- USA- (-1989)

Citation Formats

De Boer, J., and Snider, F.G. Magnetic and chemical variations of Mesozoic diabase dikes from eastern North America: evidence for a hotspot in the Carolinas. United States: N. p., 1979. Web. doi:10.1130/0016-7606(1979)90<185:MACVOM>2.0.CO;2.
De Boer, J., & Snider, F.G. Magnetic and chemical variations of Mesozoic diabase dikes from eastern North America: evidence for a hotspot in the Carolinas. United States. doi:10.1130/0016-7606(1979)90<185:MACVOM>2.0.CO;2.
De Boer, J., and Snider, F.G. Thu . "Magnetic and chemical variations of Mesozoic diabase dikes from eastern North America: evidence for a hotspot in the Carolinas". United States. doi:10.1130/0016-7606(1979)90<185:MACVOM>2.0.CO;2.
@article{osti_6204332,
title = {Magnetic and chemical variations of Mesozoic diabase dikes from eastern North America: evidence for a hotspot in the Carolinas},
author = {De Boer, J. and Snider, F.G.},
abstractNote = {Tholeiitic diabase dikes of Late Triassic and Early Jurassic age occur in swarms throughout the Appalachians. The intrusions exhibit regional variations in magnetic and chemical parameters. Aeromagnetic and ground-magnetic anomalies are highest over dikes in the Carolinas. High amplitude is due primarily to a stronger magnetization (the induced component dominates and is nearly constant within individual intrusions). Effects of host-rock magnetization, thermoremanence, and dike width, attitude, and orientation are insignificant. Chemically the Carolinas dikes are characterized by higher mean values for total iron and relatively low TiO/sub 2/ content. The magnetic and chemical patterns are reminiscent of those found for tholeiitic complexes over oceanic hotspots (Galapagos, Iceland), and suggest that the Carolinas may have been the site of such a feature in Late Triassic--Early Jurassic time. Crustal arching, rifting, and volcanism probably origniated in the Carolinas. Tectonic-volcanic activity gradually migrated northeast (and possibly, southwest) along the Appalachian axis with enlargement of the crustal bulge. In Jurassic time, spreading began farther east; the crustal stress configuration changed, and the tectonic pattern was dominated by the formation of new sets of tensional fractures and sinistral slip along pre-existing faults.},
doi = {10.1130/0016-7606(1979)90<185:MACVOM>2.0.CO;2},
journal = {Geol. Soc. Am., Bull.; (United States)},
number = ,
volume = 90:2,
place = {United States},
year = {1979},
month = {2}
}