New Insights into Mesozoic Magma Plumbing Systems

New Insights into Mesozoic Magma Plumbing Systems


TITLE: From Dale Earnhardt's Mausoleum to Giant Lava Flows: New Insights into Mesozoic Magma Plumbing Systems

Presenter: Dr. LeeAnn Srogi, Professor and chairperson, Department of Geology & Astronomy, West Chester University, West Chester, PA 19383. 610-436-2721.

 200 million years ago, flood basalts covered our region as the supercontinent Pangaea rifted apart and the modern Atlantic Ocean formed. Lava flows were fed by magma "plumbing systems" that transported mafic magmas from the upper mantle through the crust. The tremendous production of basaltic magma within a geologically short period of time may be linked to mass extinctions or global-scale environmental disruptions. Today this failed rift valley is preserved as a narrow belt that curves across southeastern Pennsylvania containing Mesozoic-age sedimentary rocks intruded by diabase and gabbro. The igneous rocks are important sources of commercial aggregate, dimension stone, and interesting mineral specimens. This talk explores two neighboring magma plumbing systems in the western end of the Newark Basin: the Morgantown Sheet and the Jacksonwald Syncline. Both systems were tilted after the magma crystallized, so that cross-sections of the plumbing system are exposed from shallow levels in the north to deeper levels in the south. Our study of the igneous rocks has revealed different features at different crustal levels that give us new insights into how magma chambers crystallize.


Dr. LeeAnn Srogi is professor and chair of the Department of Geology & Astronomy at West Chester University. She grew up in suburban Detroit where her earliest memories include picking out interesting stones and fossils - now she teaches mineralogy and petrology classes. She came east for college and received her B.S. in Geology from Yale University (1977). Her Ph.D. dissertation in Geology from the University of Pennsylvania (1988) was on the igneous and metamorphic rocks of the Wilmington Complex, Delaware, with Dr. Mary Emma Wagner. She taught at UPenn, Smith College, and Ohio Wesleyan University before joining the WCU faculty in 1991. Her current research collaborations with faculty and students include the geology and tectonics of Mesozoic continental-rift igneous rocks; the metamorphic and tectonic history of the Wissahickon Formation; and how values, emotions, and attitudes shape student learning. Her non-rock interests include music (especially classical and jazz), reading, cooking, films, nature hikes, and ecosystem gardening with native plants.

5:45pm reception (with refreshments) followed by the seminar at 6:00 in caputo 210.