A hawaiite dyke dated at 3.88 ± 0.05 Ma from the Mount Morning eruptive centre intrudes a diamictite deposit at Gandalf Ridge in the southern Ross Sea. The dyke has been dextrally offset up to 6 m horizontally by faults interpreted as the onshore continuation of the West Antarctic rift system (WARS) fault array. Felsic dykes emplaced during the Miocene are also present at Gandalf Ridge. The offset of the Miocene dykes is equivalent to the offset on the hawaiite dyke, suggesting that at this locality movement on faults within WARS has been restricted to a period more recent than c. 3.88 Ma. Over this period the minimum average rate of movement on these faults within WARS is 0.0015 mm yr-1.

The diamictites of the Neoproterozoic Kapp Lyell Sequence in northern Wedel Jarlsberg Land, southwest Spitsbergen, have long been recognized as ancient glacial deposits, but their place within the global stratigraphic framework of ‘snowball Earth’ has remained unclear, owing to the complexity of superimposed Caledonian deformation and to the relatively inaccessible terrain in which they occur. Recently deglaciated exposures of the rocks now provide a more complete picture of the changing environment in which the diamictites were deposited, and new understanding of regional correlations help constrain their place in the global chronostratigraphy of the Cryogenian Period. The 2500 m thick Kapp Lyell Sequence consists of three distinct types of glaciomarine diamictite. The succession begins with about 1000 m of finely laminated diamictite containing abundant lonestones. The millimetre- to centimetre-scale laminae, apparent suspension deposits, consist of sand- to silt-sized particles of quartz and dolomite alternating with thin films of graphitic phyllite. The laminated unit gives way abruptly to 500–1000 m of unsorted, unlayered diamictite that alternates and interfingers with graded beds of conglomerate to sandstone. These apparent turbidite deposits become increasingly prevalent toward the top of the exposed section. Regional lithostratigraphic relationships suggest that the Kapp Lyell sequence corresponds to the second major stage of Neoproterozoic glaciation at c. 635 Ma. The graphitic material in the laminated unit yields δ13C values in the range of −20 to −22 ‰, pointing to a biogenic origin and an active marine biosphere at the time of deposition. The preservation of organic carbon and unusually large ratios of highly reactive Fe to total Fe suggest that low oxygen conditions prevailed in the deep basin that received these sediments. The transition from laminated, to unsorted, to graded diamictites may represent change from (1) a stable ice margin that released rare icebergs into a deep, quiet basin to (2) a collapsing ice sheet that unleashed flotillas of icebergs and large volumes of sediment to (3) submarine landslides that triggered turbidity flows from the rapidly deposited, gravitationally unstable sediments. The Kapp Lyell diamictite sequence appears to chronicle the demise of a large ice mass in this part of the Neoproterozoic world.

At two localities adjacent to Hatherton Glacier, Darwin Mountains, a thick glacio-lacustrine sequence underlies the main diamictite facies of the Darwin Tillite (Metschel Tillite), and at one of these locations a glacio-lacustrine sequence also conformably overlies the diamictite. These deposits record the initial advance and final retreat of the Gondwana ice cap. Other, pro- and periglacial phases within these sequences record several minor advances and retreats of the ice sheet. Carbonaceous sediments above and below the main diamictite phase show that vegetation was established near the ice margin, suggesting that present-day ice margin temperatures are colder than those experienced during the Permo-Carboniferous (Gondwana) glaciation. It appears that there was little or no erosion of the Devonian Taylor Group which underlies the glacial sequence. The apparent erosional nature of the contact between the Permo-Carboniferous glacial sequence and the overlying Permian coal measures is attributed to surface winnowing of unconsolidated tills and locally the units are conformable.