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Glacial geology
Published in Barry G. Clarke, Engineering of Glacial Deposits, 2017
Glaciomarine sediments are deposited in fjords, on the continental shelf and deep sea environments. The deposition process is complex (Figure 2.17) because it is the interaction between the glacial, marine, biogenic environments and inputs from rivers and wind. In fjords, the sedimentation is influenced by tidal water, floating glaciers, river streams and slope and marine processes. Glaciomarine deposits on the continental shelf are influenced by grounded ice margins, ice shelves and open marine processes. Figure 2.7 shows the type and distribution of glaciomarine deposits in a fjord, highlighting the fact that glacial soils can range from diamictons, outwash, rhythmites, turbidites to bioturbidites. Rhythmites are a result of periodic sedimentation resulting in laminated deposits. Turbidites are a result of the suspension of fine particles creating a dense fluid, which is able to transport coarser particles.
Strong tides during Cryogenian glaciations: tidal rhythmites from early and late Cryogenian glacial successions and interglacial beds, South Australia
Published in Australian Journal of Earth Sciences, 2023
High-quality paleomagnetic and rock magnetic data for the red brown Elatina rhythmite at Pichi Richi Pass, including positive fold tests on soft-sediment slumps and rock-magnetic tests (high-field isothermal remanence, thermoremanence, and the elongation–inclination method), plus data for correlative strata elsewhere in the Adelaide Rift Complex, established the early acquisition and minimal inclination-shallowing of remanence directions and the low paleolatitude (≤10°) of the terminal Cryogenian Elatina glaciation (Schmidt et al., 1991, 2009; Schmidt & Williams, 1995, 2013). Paleomagnetic data for red beds from the Angepena Formation of the interglacial succession between the Sturt and Elatina glaciations (Figure 2; Williams & Schmidt, 2015), together with paleomagnetic data for pre-interglacial beds from the Officer Basin (Pisarevsky et al., 2001, 2007), indicated that southern Australia lay in low paleolatitudes (6–10°) during the interglacial interval and the preceding Sturt glaciation.