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After the Elatina glaciation of Snowball Earth, at least four distinct glacial advances and sea-level retreats punctuated Ediacaran time: Gaskiers glaciation (580 Ma), Fauquier glaciation (571 Ma), Bou-Azzer glaciation (566 Ma) and Hankalchough glaciation (551 Ma). Tillites or diamictites are commonly controversial, but periglacial paleosols with distinctive physical structure and degree of chemical weathering offer supporting evidence of glaciation and sea-level change useful for stratigraphic correlation. This paper reviews glacial advances of the Ediacaran stratotype and other sequences, and also reveals the value of paleosols and chemical index of alteration to understand the upper Squantum and Brookline members of the Roxbury Conglomerate near Boston, Massachusetts. The Boston Bay ice wedges are periglacial paleosols, and evidence of maritime glacial climate like that of modern coastal Greenland and Arctic Canada. Simple discoidal vendobiont fossils (Aspidella terranovica) in the Dorchester Member of the Roxbury Conglomerate and in the Cambridge Argillite are in heterolithic shale–siltstone facies that are interpreted as intertidal to shallow marine environments. Local marine transgressions and other paleosols showing significant chemical weathering represent temperate interglacial paleoclimates. Short glacial advances affecting climate and sea-level enable subdivision of the Ediacaran Period. Four distinct glacial advances and sea-level retreats punctuated Ediacaran time: Gaskiers (580 Ma), Fauquier (571 Ma), Bou-Azzer (566 Ma), Hankalchough (551 Ma). Paleosols with distinctive structures such as ice wedges were periglacial. Squantum Member diamictites near Boston, Massachusetts are Gaskiers age. [ABSTRACT FROM AUTHOR]

Recently acquired seismic data in the eastern portion of the Amadeus Basin of central Australia have enabled disconformities at the base of both the Sturt and Elatina glaciogenic sequences within the Neoproterozoic succession to be mapped on a semi-regional scale. On a more detailed scale, along the shallowly shelving eastern flank of the basin, seismic data have revealed features that demarcate the transition from a grounded to floating, or possible absent, Sturt ice-sheet. Coincident with this transition is an extensive mound-like accumulation of glacial debris, some 10 to 15km wide, 300 m high and extending at least 150km subparallel to the northeast-southwest-oriented basin margin. This glacial debris entered the basin subglacially through meandering tunnel valleys, one of which can be mapped seismically. [ABSTRACT FROM AUTHOR]

The Wet Cave vertebrate fossil deposit of the Naracoorte Caves in south-eastern South Australia contains a rich and diverse assemblage of small mammal fauna known to span the Upper Pleistocene–Holocene. Here, we describe five previously unidentifiedin situunits (A, B, C, E and F) and one likely reworked unit (D) in the Wet Cave sedimentary profile, which are correlated with paleoclimatic conditions associated with the Last Glacial Cycle. Additional radiocarbon dates presented here provide a finer temporal resolution for the upper sections of the sequence than previously available and reveal rapid deposition of polished quartz sands laminated with brown silts during the last glacial maximum (LGM). Change in sediment type and depositional processes are dated from 16.8 to 16.4 k cal y BP and are associated with the onset of deglaciation. The characteristics of the fivein situdepositional units are similar to those identified from the contemporaneous fossil and sedimentary sequence of Blanche Cave 3rd Chamber, located approximately 400 m away, reflecting interactions between paleoclimate, sediment mobility and deposition at this locality. Greater variation is evident between the Wet Cave sedimentary profile and the inner chamber of Robertson Cave, located approximately 6 km away and shows that local processes and cave structure exerted some control on sediment accumulation. Paleoclimatic inferences from the depositional sequence of Wet Cave are broadly consistent with those inferred from regional landforms for south-eastern Australia but provide a local signal more suitable for cross-correlation of the fossil faunas. In particular, the Wet Cave sequence suggests that local conditions were relatively stable in the lead up to the LGM despite fluctuation in both local and regional effective precipitation. Sedimentary units associated with the post-LGM deglaciation are characterised by alternating sand and sandy-silt layers, assumed to reflect the impact of enhanced seasonality and/or climatic fluctuation leading towards the Holocene. [ABSTRACT FROM AUTHOR]

The late Early Permian (273 - 271 Ma) Wandrawandian Siltstone in the southern Sydney Basin of New South Wales represents a marine highstand that can be correlated over 2000 km. A mainly fine-grained terrigenous clastic succession, the Wandrawandian Siltstone contains evidence for cold, possibly glacial conditions based on the presence of outsized clasts and glendonites, mineral pseudomorphs after ikaite, a mineral that forms in cold (0 - 7°C) marine sediments. A lithostratigraphic and facies analysis of the unit was conducted, based on extensive coastal outcrops and continuous drillcores. Eight facies associations were identified: (i) siltstone; (ii) siltstone with minor interbedded sandstone; (iii) interbedded tabular sandstone and siltstone; (iv) admixed sandstone and siltstone to medium-grained sandstone; (v) discrete, discontinuous sandstone intervals; (vi) chaotic conglomerate and sandstone in large channel forms; (vii) chaotically bedded and pervasively soft-sediment-deformed intervals; and (viii) tuffaceous siltstone and claystone. Using lithology and ichnology, relative water depths were ascribed to each facies association. Based on these associations, the unit was divided into five informal members that reveal a history of significant relative sea-level fluctuations throughout the formation: member I, interbedded/admixed sandstone and siltstone; member II, siltstone; member III, slumped masses of members I and II; member IV, siltstone and erosionally based lensoid sandstone beds and channel bodies; and member V, interbedded/admixed sandstone and siltstone with abundant tuffs. Member I marks an initial marine transgression from shoreface to offshore depths. Member II records the maximum water depth of the shelf. Member III is interpreted to be a slump sheet; plausible mechanisms for its emplacement include seismicity produced by tectonism or glacio-isostatic rebound, changes in pore-water pressures due to sea-level fluctuations, or an increase in sedimentation rates. Members IV and V record minor fluctuations in depositional environments from offshore to shoreface water depths. Member IV includes regionally extensive, large channel bodies, with composite fills that are interpreted as storm-influenced mass-flow deposits. Member V includes a greater abundance of volcanic ash. Glacial controls (isostasy, eustasy) and tectonic affects may have worked in concert to produce the changes in depositional environments observed in the Wandrawandian Siltstone. [ABSTRACT FROM AUTHOR]

Examines the sedimentary and cryogenic features indicating a periglacial aeolian sand sheet in Stuart Shelf, South Australia. Determination of the dominant paleowind direction; Importance of periglacial aeolian activity during the Neoproterozoic glaciation; Generations of periglacial cryogenic structures.