The African Erosion Surface: A Continental-scale Synthesis of Geomorphology, Tectonics, and Environmental Change over the Past 180 Million Years (GSA Memoir 201)

In This Memoir, Burke And Gunnell Draw On Anglophone And Francophone Work To Analyze The African Continent's Distinctive Basin-and-swell Topography. Exploring Topics Such As Landforms, Bauxites And Laterites, Fission-track Studies, Climatic Changes, Volcanic Rock Distribution, Hotspots, Mantle Plumes, And Rifts, As Well As Deep And Shallow Mantle Geophysics, Ocean Floor Evolution, Continental Flooding, And Offshore Sediment Deposition, The Authors Have Pieced Together A Coherent, Continent-wide Reconstruction Of Landscape Development During The Past 200 Million Years. Two Episodes Of Continental Breakup And The Formation Of Ocean Floor Were Followed By Erosion That Reduced The Continent To A Low-elevation And Low-relief African Surface By Late Cretaceous Times. Africa's Present-day Topography Developed Mostly During The Past 30 Million Years As The African Surface Underwent Swell Uplift And Climate Changed Radically After The Antarctic Ice Sheet First Formed. Northern Hemisphere Glaciation And Related Sahara Initiation 3 Million Years Ago Were Africa's Most Recent Great Changes.--publisher's Website. Abstract -- The Unique Tectonic Identity Of The African Continent: Expected Effects On The History Of Its Eroding Land Surface -- General Characteristics Of The African Surface -- What Is The African Surface? -- The African Surface: A Composite Surface -- Tectonic Evolution Of Afro-arabia And Its Controls On The History Of The African Surface -- Structures That Influenced Local Relief On The African Surface During Its Evolution -- The African Surface In Basins That Experienced Marine Incursions Between 100- Ma And 34 Ma -- Regional Characteristics Of The African Surface -- The African Surface In Its Type Area: Southern Africa -- History Of The Concept Of The African Surface -- Recent Interpretations Of The African Surface -- The African Surface In Southern Africa: A Summary -- West Africa: From Senegal To Cameroon -- Central Africa -- East Africa: The Great Swell And The Rift System -- Northeastern Africa And Arabia -- Summary: Regional Age Brackets For The African Surface -- Bauxite Occurrences As Indices Of The African Surface: Their Value And Limitations -- Bauxites ... And Bauxites -- Examples Of Orthobauxites And Laterites In Afro-arabia Inherited From The Last Great Bauxite-forming Interval, 70-40 Ma -- Staircases Of Bauxite- And Laterite-capped Surfaces In Their Key Area: West Africa -- Bauxites In Africa That May Have Formed Since The End Of The Main Bauxite-forming Interval, I.e, After 40 Ma -- Synthesis On Bauxites And Laterites -- The Imprint Of Continental-scale Paleoclimactic Variations In Afro-arabia -- Cretaceous Times, 140-65 Ma -- Earlier Cenozoic Times, 65-34 Ma -- Early Oligocene To Late Pliocene Times, 34-2.8 Ma -- Late Pliocene And Quaternary Times, Since 2.8 Ma -- The African Surface In The Post-30 Ma Basin-and-swell Reference Frame -- Burial Of The African Surface In Africa's Active Continental Basins -- Topographic Uplift Of The African Surface On Africa's Swells -- Volcanism Or Absence Thereof: Its Relevance To The African Surface -- The African Surface On Africa's Swells: General Characteristics -- The Great Swell Of South Africa -- Implications Of The Cenozoic Swell Model For The History Of The Great Escarpments At Africa's Continental Margins -- Long-lived Escarpments Close To Rifted Continental Margins? A Return To The Historical Type Area Of The African Surface In Southern Africa -- A New Perspective On The Great Escarpment Of Southern Africa -- Summary And Conclusions. By Kevin Burke, Yanni Gunnell. Includes Bibliographical References (p. 59-66). The African Erosion Surface: A Continental-Scale Synthesis of Geomorphology, Tectonics, and Environmental Change over the Past 180 Million Years......Page 1 ISBN-13: 978-0-8137-1201-7......Page 3 Contents......Page 4 Photo: Africa’s Rising Swells......Page 6 Abstract......Page 8 The Unique Tectonic Identity of the African Continent: Expected Effects on the History of Its Eroding Land Surface......Page 9 General Characteristics of the African Surface......Page 13 Regional Characteristics of the African Surface......Page 20 Bauxite Occurrences as Indices of the African Surface: Their Value and Limitations......Page 38 The Imprint of Continental-Scale Paleoclimatic Variations in Afro-Arabia......Page 44 The African Surface in the Post–30 Ma Basin-and-Swell Reference Frame......Page 47 Implications of the Cenozoic Swell Model for the History of the Great Escarpments at Africa’s Continental Margins......Page 53 Summary and Conclusions......Page 64 References Cited......Page 66 Back......Page 74