Glaciolacustrine and glaciomarine processes (glacial deposition in lake and marine basins) is different than glacioterrestrial deposition, which I discussed in the part 1 video over glacial depositional systems: [ Ссылка ]. But if glaciers form on land, how do they deposit sediment in oceans or lakes? In this video, I discuss how glaciolacustrine and glaciomarine deposition works, the sedimentary structures and stratigraphy of ice-proximal versus ice-distal glaciomarine systems (varves, ice-berg scour marks, dropstones, rain-out diamict, till, submarine fans and turbidites), and the major glacio-epochs (ice ages) of Earth's history and how the evidence of these ice age events, such as snowball earth can be interpreted. Glaciers move over land and sometimes deposit sediment on land in moraines or other landforms, however, most glacial deposits in the rock record are deposited in marine environments. This is because glaciers move downslope and typically all end up leading to an ocean or lake basin at the end of the downslop, thus, these glaciers transport sediment into ocean or lake basins. Glaciers break up into ice bergs once they hit the water body and as they melt, they drop sediment into the basin floor, these are called dropstones. Ice bergs can also scour the basin floor as the move along the surface if their bottom half is large enough. Submarine fans from meltwater flows coming from the base of the glacier also form. Glacial till deposits directly from the glacier form more proximal to the basin margin or fjord that the glacier carved. We can also track sea level changes with glaciomarine deposits because the glacial deposits that form during high sea level are distinct from those at low sea level. Glaciomarine sediments in the rock record represent the major lines of evidence for glaciations or ice ages throughout Earth's History. I close out the video by discussing the liklihood of snowball earth based on the glacial deposits in the rock record.
References:
Depositional Sedimentary Environments: [ Ссылка ]
Facies models 4: [ Ссылка ]
Carolyn H. Eyles and Nick Eyles, 2010. Glacial Deposits. Facies models 4. Toronto: Geological Association of Canada, pp. 73-104. [ Ссылка ]
Dowdeswell, J. A., Canals, M., Jakobsson, M., Todd, B. J., Dowdeswell, E. K. & Hogan, K. A. (eds) 2016. Atlas of Submarine Glacial Landforms: Modern, Quaternary and Ancient. Geological Society, London, Memoirs, 46, 437– 444. [ Ссылка ]
Domack, E.W., Powell, R., 2018. Modern Glaciomarine Environments and Sediments: An Antarctic Perspective. In: Menzies, J., van Der Meer, J. (Eds.), Past Glacial Environments, 2. Elsevier, pp. 181-272. [ Ссылка ]
Lee, J., 2018. Glacial Lithologies and Stratigraphy. In: Menzies, J., van Der Meer, J. (Eds.), Past Glacial Environments, 2. Elsevier, pp. 377-429. [ Ссылка ]
Young, G.M., 2018. Precambrian Glacial deposits: their origin, Tectonic setting, and key role in Earth evolution. In: Menzies, J., van Der Meer, J. (Eds.), Past Glacial Environments,2. Elsevier, pp. 17–45. [ Ссылка ]
McClenaghan, M.B., Paulen, R.C., 2018. Application of Till Mineralogy and Geochemistry to Mineral Exploration. In: Menzies, J., van Der Meer, J. (Eds.), Past Glacial Environments,2. Elsevier, pp. 689-751. [ Ссылка ]
GEO GIRL Website: [ Ссылка ] (visit my website to see all my courses, shop merch, learn more about me, and donate to support the channel if you'd like!)
0:00 Glacioterrestrial vs. glaciomarine deposition
2:01 Glaciolacustrine deposition
5:32 Outcrop examples of glaciolacustrine deposits
7:31 Ice-proximal glaciomarine deposition
11:38 Ice-proximal glaciomarine stratigraphy
17:17 Ice-distal glaciomarine deposition
17:50 Outcrop examples glaciomarine deposits
19:40 Glaciation periods in Earth's history
23:16 Was there a Snowball Earth?
Directly offset your carbon footprint with Wren: [ Ссылка ]
Non-textbook books I recommend:
Oxygen by D. Canfield: [ Ссылка ]
Brief history of Earth by A. Knoll: [ Ссылка ]
Life on young planet by A. Knoll: [ Ссылка ]
Some assembly required by N. Shubin: [ Ссылка ]
Your inner fish by N. Shubin: [ Ссылка ]
Oxygen by N. Lane: [ Ссылка ]
Alien Oceans by K. Hand: [ Ссылка ]
Life's Engines: [ Ссылка ]
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