Book contents
- Frontmatter
- Contents
- List of contributors
- Preface
- Acknowledgements
- 1 Geodynamic controls on glaciation in Earth history
- 2 Glacial-marine facies in a continental rift environment: Neoproterozoic rocks of the western United States Cordillera
- 3 The Neoproterozoic Konnarock Formation, southwestern Virginia, USA: glaciolacustrine facies in a continental rift
- 4 Glaciogenic deposits of the Permo-Carboniferous Dwyka Group in the eastern region of the Karoo Basin, South Africa
- 5 Itararé Group: Gondwanan Carboniferous-Permian of the Paraná Basin, Brazil
- 6 The interpretation of massive rain-out and debris-flow diamictites from the glacial marine environment
- 7 Neoproterozoic tillite and tilloid in the Aksu area, Tarim Basin, Uygur Xinjiang Autonomous Region, Northwest China
- 8 Lithology, sedimentology and genesis of the Zhengmuguan Formation of Ningxia, China
- 9 Architectural styles of glacially influenced marine deposits on tectonically active and passive margins
- 10 Marine to non-marine sequence architecture of an intracratonic glacially related basin. Late Proterozoic of the West African platform in western Mali
- 11 The enigmatic Late Proterozoic glacial climate: an Australian perspective
- 12 Isotopic signatures of carbonates associated with Sturtian (Neoproterozoic) glacial facies, central Flinders Ranges, South Australia
- 13 Reactive carbonate in glacial systems: a preliminary synthesis of its creation, dissolution and reincarnation
- 14 A Permian argillaceous syn- to post-glacial foreland sequence in the Karoo Basin, South Africa
- 15 A palaeoenvironmental study of black mudrock in the glacigenic Dwyka Group from the Boshof-Hertzogville region, northern part of the Karoo Basin, South Africa
- 16 Late Paleozoic post-glacial inland sea filled by fine-grained turbidites: Mackellar Formation, Central Transantarctic Mountains
- 17 Ice scouring structures in Late Paleozoic rhythmites, Paraná Basin, Brazil
- 18 Soft-sediment striated surfaces and massive diamicton facies produced by floating ice
- 19 Environmental evolution during the early phase of Late Proterozoic glaciation, Hunan, China
18 - Soft-sediment striated surfaces and massive diamicton facies produced by floating ice
Published online by Cambridge University Press: 06 July 2010
- Frontmatter
- Contents
- List of contributors
- Preface
- Acknowledgements
- 1 Geodynamic controls on glaciation in Earth history
- 2 Glacial-marine facies in a continental rift environment: Neoproterozoic rocks of the western United States Cordillera
- 3 The Neoproterozoic Konnarock Formation, southwestern Virginia, USA: glaciolacustrine facies in a continental rift
- 4 Glaciogenic deposits of the Permo-Carboniferous Dwyka Group in the eastern region of the Karoo Basin, South Africa
- 5 Itararé Group: Gondwanan Carboniferous-Permian of the Paraná Basin, Brazil
- 6 The interpretation of massive rain-out and debris-flow diamictites from the glacial marine environment
- 7 Neoproterozoic tillite and tilloid in the Aksu area, Tarim Basin, Uygur Xinjiang Autonomous Region, Northwest China
- 8 Lithology, sedimentology and genesis of the Zhengmuguan Formation of Ningxia, China
- 9 Architectural styles of glacially influenced marine deposits on tectonically active and passive margins
- 10 Marine to non-marine sequence architecture of an intracratonic glacially related basin. Late Proterozoic of the West African platform in western Mali
- 11 The enigmatic Late Proterozoic glacial climate: an Australian perspective
- 12 Isotopic signatures of carbonates associated with Sturtian (Neoproterozoic) glacial facies, central Flinders Ranges, South Australia
- 13 Reactive carbonate in glacial systems: a preliminary synthesis of its creation, dissolution and reincarnation
- 14 A Permian argillaceous syn- to post-glacial foreland sequence in the Karoo Basin, South Africa
- 15 A palaeoenvironmental study of black mudrock in the glacigenic Dwyka Group from the Boshof-Hertzogville region, northern part of the Karoo Basin, South Africa
- 16 Late Paleozoic post-glacial inland sea filled by fine-grained turbidites: Mackellar Formation, Central Transantarctic Mountains
- 17 Ice scouring structures in Late Paleozoic rhythmites, Paraná Basin, Brazil
- 18 Soft-sediment striated surfaces and massive diamicton facies produced by floating ice
- 19 Environmental evolution during the early phase of Late Proterozoic glaciation, Hunan, China
Summary
Abstract
Soft-sediment striated surfaces, commonly associated with massive diamictites, have been described from many pre-Quaternary glacial sedimentary sequences around the world. A number of authors interpret these associations as evidence for a subglacial origin. However, soft-sediment striated surfaces are formed by the mechanical scouring action of seabed- (or lakebed-) touching free-floating ice masses over large areas of modern high latitude continental shelves, and in glacial lakes and in lakes subject to seasonal freeze-up. Prolonged reworking of seabed and lakebed sediments by scouring ice keels can cause homogenization of preexisting stratification to form massive diamictons that may be described as iceberg turbates, sea-ice turbates or lake-ice turbates. Evidence from previous work on soft-sediment striated surfaces by other authors is presented and reviewed in the context of possible origin by scouring ice keels.
In the modern East Greenland glacimarine environment massive diamicton has been deposited during the Holocene by the combined action of iceberg-rafting and suspension settling from subglacial and seasonal terrestrial meltwater runoff. During deposition continuous scouring by deep-drafted icebergs (up to 550 m) has resulted in mechanical mixing of the diamicton. The present surface of this iceberg turbate is characterized morphologically by the typical hummocky topography of criss-crossing iceberg scour marks. We show that Quaternary ice keel scour processes have affected an order of magnitude more of the seafloor than have subglacial processes, and suggest that this order of magnitude difference probably can be applied to pre-Quaternary glacial marine and lacustrine environments. Consequently the effects of ice keel scour should be more frequently preserved than features of ice shelf grounding zone processes. Field work directed at reappraising pre-Quaternary soft-sediment striated surfaces associated with diamictites now may be appropriate.
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- Earth's Glacial Record , pp. 241 - 259Publisher: Cambridge University PressPrint publication year: 1994
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