Physical Geology Lecture: Mountain Building 2 - The Appalachians, Slides of Geology

Download Physical Geology Lecture: Mountain Building 2 - The Appalachians and more Slides Geology in PDF only on Docsity! 1 GY 111: Physical Geology Lecture 31: Mountain Building 2: The Appalachians Last Time Mountain Building 1 A) Distribution of mountain belts (the return of plate tectonics) B) Isostasy and the Rock Cycle (again) C) Thrust Faults in the Rockies (movie) Mountain Belts Old Mountains New Mountains Isostasy (Isostacy) The depression of the asthenosphere beneath mountain belts due to loading followed by rebounding as erosion occurs. Styrofoam sheets on water The Rock Cycle Faults on Maps There is a special class of reverse fault that is common in mountain belts Thrust Faults Docsity.com 2 Today’s Agenda Mountain Building 2 A) Appalachian “provinces” (Alabama!) B) Paleozoic time-frame/orogenies C) How to make a mountain belt Web notes 42 Appalachian Mountains Appalachian Mountains Four geological belts are identified 1) Plateaus (undeformed) 2) Valley and ridge (folded/faulted) 3) Piedmont (Highly metamorphosed) 4) Blue Ridge (igneous intrusions) Appalachian Provinces We only see the first 3 in Alabama 1) Plateaus (undeformed) 2) Valley and ridge (folded/faulted) 3) Piedmont (Highly metamorphosed) Appalachian Provinces We only see the first 3 in Alabama 1) Plateaus (undeformed) 2) Valley and ridge (folded/faulted) 3) Piedmont (Highly metamorphosed) What happened? When did it happen? When? Ediacaran (600 to 550 Ma) Neo- Proterozoic Cambrian (505 to 550 MA) Ordovician (441 to 505 MA) Silurian (418 to 441 MA) Devonian (362 to 418 MA) Mississippian (320 to 362 MA) Pennsylvanian (286 to 320 MA) Permian (245 to 286 MA) Paleozoic PeriodEra Time of origin of the Appalachian Mountains Docsity.com 5 Paleozoic Tectonics (Acadian Orogeny) Cambrian Taconic Orogeny* (NE)Ordovician Silurian Acadian Orogeny* (E)Devonian Mississippian Pennsylvannian Alleghenian Orogeny* (SE) Permian North AmericaPeriod Silurian Devonian Late Ordovician Laurentia Baltica Isla nd arc A B A B The next tectonic event (the Acadian Orogeny) was caused by the approach of Baltica (Europe) Sub duc tion zon es Baltica Baltica Paleozoic Tectonics (Acadian Orogeny) Paleozoic Tectonics (Alleghenian Orogeny) Cambrian Taconic Orogeny* (NE)Ordovician Silurian Acadian Orogeny* (E)Devonian Mississippian Pensylvannian Alleghenian Orogeny* (SE) Permian North AmericaPeriod http://www.jamestown-ri.info/pangaea270.jpg Mississippian Penn-Permian Mississippian B Lastly, along comes Gondwanna and…. …well you get the idea. A B Subduction zone A B Paleozoic Tectonics (Alleghenian Orogeny) Pennsylvanian B Lastly, along comes Gondwanna and…. …well you get the idea. A B Suture zone A B Suture zone Paleozoic Tectonics (Alleghenian Orogeny) Pennsylvanian B Lastly, along comes Gondwanna and…. …well you get the idea. Paleozoic Tectonics (Alleghenian Orogeny) Docsity.com 6 The End Docsity.com