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Site content related to keyword: "Enstatite (Bronzite)"

The Bringhurst Gabbro: A GeoAdventure in the Delaware Piedmont

Bringhurst Woods Park Rocks, The Bringhurst Gabbro

A field trip to Bringhurst Woods Park is appropriate for students in grades 5 and up (10 years and older), and provides an opportunity to observe intrusive plutonic igneous rocks that have intruded into country rock, which in this case is the blue rock or what geologists call the Brandywine Blue Gneiss. In addition, the minerals in the pluton are large, easily identified, and interesting. Mineral collecting is not allowed within the park, however permission may be obtained to collect along Shellpot Creek southeast of the park. Please do not use rock hammers on the rocks in the park.

B5 Sedimentary Petrology of the Cretaceous Sediments of Northern Delaware in Relation to Paleogeographic Problems

B5 Sedimentary Petrology of the Cretaceous Sediments of Northern Delaware in Relation to Paleogeographic Problems

The non-marine Cretaceous sediments of northern Delaware older than the Magothy formation cannot be divided accurately into formations or mappable geologic units because their lithologic characteristics are very similar. However, two heavy mineral zones can be distinguished in these deposits: a lower staurolite-kyanite-tourmaline-zircon zone, and an upper tourmaline-zircon-rutile zone with abundant alterites. They have been named the Patuxent zone and the Patapsco-Raritan zone respectively. The Magothy formation is characterized by abundant staurolite and also contains significant amounts of tourmaline. The marine Upper Cretaceous deposits have a greater variety of heavy minerals than the underlying non-marine sediments. They contain abundant epidote; chloritoid, first appearing at the base of the Merchantville formation, is persistently present. Garnet is found in the Merchantville and the Mount Laurel-Navesink formations. The heavy mineral composition of the Cretaceous sediments is shown in table IV.