Geologic_Formation_of_Pennsylvania

Geologic Formation of Pennsylvania Pennsylvania’s land started with the idea of plate tectonics and convection currents. The mantle of the Earth is hotter than the lithosphere, which causes materials to sink and eventually rise back up to the surface. These continents move towards or away from each other with convection currents. Then, during the Ordovician Period mountain building occurred. Convection currents that pulled the continents together formed the Appalachian Mountains. Subduction of materials causes volcanoes to form, and volcanoes eventually covered the water that left ash or Bentonite in the quarries today. Next, during the Cambrian and Ordovician periods North America still remained above the sea. Eventually weathering wore away the surface of the land, and erosion moved these sediments away. The sediments that were deposited formed limestone. Limestone is also called carbonates that are formed by chemical deposition. Limestone is made out of shells of marine animals and mineral particles and is deposited far offshore in warm areas. This formation later settles on the seafloor and turns back into rock. Mud was also deposited farther offshore creating silt and clay. These sediment particles created Martinsburg shale. At limestone, formed, rock, dolomite, tuscarora, shale, found, deposited, contains, ash, sandstone, quartz, ordovician, clay, bentonite, appalachian, together, slate, sedimentary, sand, rocks, quarry, period, mountains, mountain, martinsburg, feet, eventually, eastern, deposit, currents, convection, conglomerate, calcite, away, volcanoes, turns, tectonics, surface, silt, sediments, plate, original, offshore, mud, mineral, materials, mainly, later, land