Petrogenesis of a Silicic Magma Chamber Periodically Invaded by Basaltic Magma: the Isle au Haut Igneous Complex, Maine.
Chapman M. 1996. Petrogenesis of a Silicic Magma Chamber Periodically Invaded by Basaltic Magma: the Isle au Haut Igneous Complex, Maine.. University of Massachusetts
From Abstract, 'Field and textural relationships also indicate that complex hybridization has taken place between the lower massive gabbroic unit and the underlying granite.' "The plutonic rocks of the Paleozoic Isle au Haut Igneous Complex, Maine (424+- 1 Ma.), are a trimodal assemblage of granites, diorites, and gabbros. Exposed from the top to the bottom of the pluton, the complex consists of an enclave-bearing granite, a composite layered sequence of alternating gabbroic and dioritic units, a thick and massive gabbroic unit, and a base of an enclave-void granite. Field and textural relationships for the composite layer show a sequence of ten alternating gabbroic and dioritic units that were liquid or largely liquid contemporaneously. The gabbros are chilled against the underlying diorite, from which cylindrical pipes of a component of the diorite intrude vertically into the gabbro. Immediately below the chilled gabbro contacts, chilled, lobate, pillow-like structures have become detached and sunk into the diorite for a half meter. These pillows are compositionally identical to the chilled margins of the overlying gabbro and generally preserve their liquid composition." /STUDY LOCATIONS:/ /ISLE AU HAUT/
- Type
- Academic
- Authors
- Chapman, Marhsall
- Date of Issue
- 1996-05
- Publisher
- University of Massachusetts
- Units
- ACAD
- Keywords
- Diorite, Dissertation, gabbro, Geochronology, Geology, Geomorphology, Geothermal Activity, Granite, Igneous Rocks, Intrusions, Isle Au Haut, Lithology, Magma, Petrology, Plutonic Rocks, Rocks, Tholeiites