Evolution of tholeiitic diabase sheet systems in the eastern United States: examples from the Culpeper Basin, Virginia-Maryland, and the Gettysburg Basin, Pennsylvania
High-TiO2, quartz-normative (HTQ) tholeiite sheets of Early Jurassic age have intruded mainly Late Triassic sedimentary rocks in several early Mesozoic basins in the eastern US. Field observations, petrographic study, geochemical analyses and stable isotope data from three HTQ sheet systems were used to develop a general model of magmatic differentiation and magmatic-hydrothermal interaction for HTQ sheets. The three sheet systems have remarkably similar major-oxide and trace-element compositions. Cumulus and evolved diabase in comagmatic sheets separated by tens of kilometers are related by igneous differentiation. Differentiated diabase in all three sheets have petrographic and geochemical signatures and fluid inclusions indicating hydrothermal alteration beginning near magmatic temperatures and continuing to relatively low temperatures. Sulfur and oxygen isotope data are consistent with a magmatic origin for the hydrothermal fluid. -from Authors
Citation Information
Publication Year | 1995 |
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Title | Evolution of tholeiitic diabase sheet systems in the eastern United States: examples from the Culpeper Basin, Virginia-Maryland, and the Gettysburg Basin, Pennsylvania |
DOI | 10.1016/0377-0273(94)00085-U |
Authors | Laurel G. Woodruff, A. J. Froelich, Harvey E. Belkin, D. Gottfried |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Journal of Volcanology and Geothermal Research |
Index ID | 70019652 |
Record Source | USGS Publications Warehouse |
USGS Organization | Eastern Mineral and Environmental Resources Science Center |