GEOLEXSummary of Citation: Wilmington
Publication: Ward, R.F., 1959, Petrology and metamorphism of the Wilmington complex, Delaware, Pennsylvania, and Maryland: Geological Society of America Bulletin, v. 70, no. 11, p. 1425-1458Usage in Publication:
Wilmington complex (new name) consists of banded gneiss comprising mafic bands of calcic plagioclase, hypersthene, augite, and commonly hornblende and thick felsic bands of quartz and andesine with minor pyroxene; in central part, gneiss has been invaded by granite [Arden] consisting of orthoclase, oligoclase-andesine, biotite, and pyroxene. To the southwest, banded gneiss grades into amphibolites. Veins of granite, apparently related to Port Deposit granodiorite, intrude southwestern part of complex. Coarse-grained undeformed gabbro stock intrudes gneiss north of Wilmington. Similar body of gabbro occurs as group of low hills surrounded by Coastal Plain sediments. Complex is bordered by Wissahickon formation (lower Paleozoic?) and Port Deposit granite. Southern edge of complex is covered by Coastal Plain sediments.
Summary of Citation: Wilmington
Publication: Srogi, LeeAnn, Wagner, M.E. and Lutz, T.M., 1993, Dehydration partial melting and disequilibrium in the granulite-facies Wilmington Complex, Pennsylvania-Delaware Piedmont: American Journal of Science, v. 293, no. 5, p. 405-462Usage in Publication:
Located in the Piedmont province of the Appalachian-Caledonian mountain belt in northern DE and southeastern PA, the Wilmington Complex is interpreted to be a deep-crustal remnant of the Cambrian-Ordovician magmatic arc, tectonically emplaced on this continent during the Late Ordovician Taconic Orogeny. It is a granulite-facies terrane for which peak pressure-temperature conditions during metamorphism are estimated at 800+/-50 deg. and 700+/-100 MPa. It was first mapped by Bascom and Miller (1920) and Bascom and Stose (1932), but Ward (1959) published the first and only study and map of the entire terrane. Intrusion by the Arden pluton, which has been dated at 502+/-20 Ma, confirms the early Paleozoic age.