0402temp_Pangaea-stu

0402temp_Pangaea-stu - The legacy of Pangaea Goosenecks of...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: The legacy of Pangaea Goosenecks of the San Juan River, Utah EARTH SCIENCE in ARIZONA and the SOUTHWEST (U.S. Geological Survey, 2007) Formation of the supercontinent Pangaea Early Permian Period 280 Ma Present‐day Southwest (Reynolds, Johnson, Kelly, Morin, & Carter, 2010, after Blakey) The legacy of Pangaea 2 Island arc collision, mountain‐building, marine flooding (all in all, a rather complicated interval) The legacy of Pangaea (R. Blakey) 3 A wealth of diverse depositional environments Coastal plains Inter‐mountain basins Marine basins Carbonate platforms The legacy of Pangaea Paleogeographic map by R. Blakey, NAU 4 Deposition on platforms and in restricted marine basins Sodium, potassium, calcium, boron salts Platform carbonates The legacy of Pangaea 5 The Paradox Basin The legacy of Pangaea Paleogeographic map by R. Blakey, NAU 6 Platform carbonate deposition = limestones Algal buildups: hydrocarbon sources The legacy of Pangaea 7 Pennsylvanian limestones exposed in today’s Southwest Pennsylvanian Hermosa Group limestones, Hermosa Cliffs, San Juan Mountains, Colorado S. Reynolds, ASU The legacy of Pangaea 8 Pennsylvanian limestones exposed in today’s Southwest Naco Formation (Pennsylvanian) Queen Creek Canyon, Arizona The legacy of Pangaea Hermosa Group (Pennsylvanian) San Juan River Canyon, Utah 9 The Paradox Basin: cross‐section Limestone Limestone Limestone Salt The legacy of Pangaea 10 Pennsylvanian Paradox Fm evaporites Halite NaCl + sylvite KCl interbedded with anhydrite CaSO4 and black muds Permian red beds (siliciclastic) The legacy of Pangaea Exposed evaporite beds, Stinking Springs, near Moab, Utah 11 The evaporites yield salt (NaCl) and potash (KCl) Moab Salt potash mine, near Canyonlands National Park, Colorado Plateau, Utah The legacy of Pangaea 12 And the carbonates yield oil and gas Aneth Oil Field, Navajo Nation, Utah The legacy of Pangaea 13 As the Paleozoic Era progressed, climate gradually became drier The legacy of Pangaea (R. Blakey) 14 Coastal plain‐eolian environment in Arizona: Supai Group (Pennsylvanian‐Permian) The legacy of Pangaea 15 Northwest Pangaea at 290 Ma (Permian) Southwest “heartland” drying out Slow regression of Absaroka seas Paleogeographic map by R. Blakey, NAU The legacy of Pangaea 16 Early Permian Southwest: increasingly arid climate Paleogeographic map by R. Blakey, NAU The legacy of Pangaea 17 Setting Hen Butte, Monument Valley, Navajo Nation, Utah‐Arizona Increasing aridity DeChelly Sandstone (aeolian) Organ Rock Shale (mudflats and streams) The legacy of Pangaea 18 (Semken) Aeolian (windborne) sediment deposition Cross‐bedded aeolian sandstone: DeChelly Sandstone, Tséyi’ (Canyon de Chelly), Navajo Nation, Arizona The legacy of Pangaea 20 Cross‐bedded aeolian sandstone: DeChelly Sandstone, Tséyi’ (Canyon de Chelly), Navajo Nation, Arizona (Eric Riggs) The legacy of Pangaea 21 Cross‐bedded aeolian sandstone: DeChelly Sandstone, Tséyi’ (Canyon de Chelly), Navajo Nation, Arizona The legacy of Pangaea 22 Sedona! Wilson Mountain, Sedona, AZ Ron Blakey, NAU http://jan.ucc.nau.edu/rcb7/ The legacy of Pangaea 23 275 Ma (Middle Permian Period) Minor regression and transgression across northern AZ The legacy of Pangaea (Ron Blakey) 24 Toroweap and Kaibab Formations (Late Permian Period ~ 270 Ma) Marine limestone Mud, sand, lime Desert aeolian sandstone (Lutgens and Tarbuck, 2000) The legacy of Pangaea 25 A synopsis of the Paleozoic Southwest The Early to Middle Paleozoic Era A long‐lived passive margin Deposition of marine sedimentary rocks (mostly limestones) by periodic transgressions Resource: Very pure limestones = calcium carbonate The Middle to Late Paleozoic Era Southwest included in the assembly of the supercontinent Pangaea Minor episode of mountain‐building: some areas raised above sea level At the same time, another transgression Limestone deposition on platforms around edge of continent Deposition of evaporites in marine basins that periodically go dry Resources: Salts, petroleum The Late Paleozoic Era Climate becomes much drier Desert aeolian deposition land = thick, cross‐bedded sandstones Resource: Today’s beautiful red‐rock landscapes! The legacy of Pangaea 26 ...
View Full Document

Ask a homework question - tutors are online