One page article discussing aspects of Australian stratigraphy; this article discusses practical Australian solutions to igneous nomenclature and the indexing of relevant Antarctic units

Crinoids, and especially comatulids as Anthometra adriani, are well represented among the macrofauna from the continental shelf offshore from Terre Adélie and George V Land, East Antarctica. These animals are suspension feeders that depend on the local current regime to feed. Nearly 500 specimens from this species were sampled during the Collaborative East Antarctic Marine Census (CEAMARC) expedition onboard the RV Aurora Australis (December 2007 to January 2008), from 46 of the 87 stations over a 400 km² area. Abiotic environmental factors (such as depth, temperature, salinity, oxygen) were measured at each site. The ecological niche of Anthometra adriani was described using Ecological Niche Factor Analysis (ENFA) and Mahalanobis Distances Factor Analysis (MADIFA). An Environmental Suitability Map (ESM) was developed for this species on the CEAMARC study area. The results show that A. adriani seems to prefer relatively cold and well-oxygenated waters in moderately deep areas. The ESM shows four optimal regions for this species: the eastern side of the George V Basin, the western part of the Mertz Bank, the southern side of the Adélie Bank, and the coastal area between the Astrolabe and Mertz Glaciers.

This paper presents tectonic elements maps for the continental margin of East Antarctica, from 38-164E, together with brief descriptions of all the major tectonic elements.

From February to March 2010, Geoscience Australia (GA) conducted an multibeam survey of the coastal waters of the Vestfold Hills in the Australian Antarctic Territory. The survey was conducted jointly with Australian Antarctic Division (AAD) and the Deployable Geospatial Survey Team (DGST) of the Royal Australian Navy. The survey was aimed primarily at understanding the the character of the sea floora round Davis to better inform studies of the benthic biota and the possible impacts of the Davis Station sewage outfall. DGST were involved so the data could be used to update and extend the nautical charts of the Davis area.

Multichannel seismic data collected off Wilkes Land (East Antarctica) reveal four main units that represent distinct phases in the evolution of the Cenozoic depositional environment. A Cretaceous synrift succession is overlain by hemipelagic and distal terrigenous sequences deposited during Phase 1. Sediment ridges and debris-flow deposits mark the transition to Phase 2. Unit 3 records the maximum sediment input from the continent and is characterized by the predominance of turbidite deposits. During Phase 4 the sediment supply from the continental margin was reduced, and draping and filling were the dominant processes on the continental rise. Unit 4 also contains the deposits of sediment wave fields and asymmetric channel-levee systems. These four units are a response to the Cenozoic evolution of the East Antarctic Ice Sheet. During Phase 1, small ice caps were formed in the innermost continental areas. The ice volume increased under temperate glacial regimes during Phases 2 and 3, when large volumes of melt-water production led to high sediment discharge to the continental rise. Change to a polar regime occurred through Phase 4, when a thick prograding wedge developed on the continental shelf and slope and the sediment transport to the rise diminished, producing general starvation conditions.

The sediments deposited beneath the floating ice shelves around the Antarctic margin provide important clues regarding the nature of sub-ice shelf circulation and the imprint of ice sheet dynamics and marine incursions on the sedimentary record. Understanding the nature of sedimentary deposits beneath ice shelves is important for reconstructing the icesheet history from shelf sediments. In addition, down core records from beneath ice shelves can be used to understand the past dynamics of the ice sheet. Six sediment cores have been collected from beneath the Amery Ice Shelf in East Antarctica, at distances from the ice edge of between 100 and 300 km. The sediment cores collected beneath this ice shelf provide a record of deglaciation on the Prydz Bay shelf following the last glaciation. Diatoms and other microfossils preserved in the cores reveal the occurrence and strength of marine incursions beneath the ice shelf, and indicate the varying marine influence between regions of the sub-ice shelf environment. Variations in diatom species also reveal changes in sea ice conditions in Prydz Bay during the deglaciation. Grain size analysis indicates the varying proximity to the grounding line through the deglaciation, and the timing of ice sheet retreat across the shelf based on 14C dating of the cores. Two of the cores contain evidence of cross-bedding towards the base of the core. These cross-beds most likely reflect tidal pumping at the base of the ice shelf at a time when these sites were close to the grounding line of the Lambert Glacier.

Northern Jetty Peninsula, incorporating Else Platform (~140 km2) and Kamenistaja Platform (~15 km2), represents a mostly ice-free low-lying region located on the western flanks of the Lambert Graben. The region is underlain by granulite-facies Proterozoic gneisses and unmetamorphosed Permian sediments. Metamorphic rock types include quartzo-feldspathic, pelitic and semi-pelitic metasedimentary rocks of probable Mesoproterozoic age (Kamenistaja Paragneiss and Else Gneiss). Minor intercalated ultramafic and calc-silicate bodies are also present. Neoproterozoic (ca. 940-1000 Ma) syn-tectonic felsic intrusives (megacrystic Chistoe Granite, Melkoe Granite and Soyuz Leucogranite) are also widespread. Proterozoic rocks are subsequently intruded by Paleozoic Jetty Granite Dykes and felsic Stagnant Pegmatites (ca. 500 Ma), alkaline mafic dykes (ca. 308-320 Ma) and Mesozoic alkaline stocks and pipes (ca. 130-150 Ma). The Toploje Member of the Amery Group (a sequence of Permo-Triassic fluvial siliciclastic rocks, which outcrop extensively on the southern and western flanks of Beaver Lake) is exposed on southwestern Kamenistaja Platform and appears fault-bounded against the high-grade Proterozoic rocks. Together with adjacent high-grade rocks in Kemp and Mac.Robertson Lands to the west, the rocks of northern Jetty Peninsula form part of an extensive Meso-Neoproterozoic high-grade mobile belt (the 'Rayner Orogeny'; ca. 900-1100 Ma). During this event, on Else Platform, peak metamorphic conditions reached pressures as much as ~6.5 to 7.5 kbar at temperatures ~ 800º C and resulted in the development of a pervasive gneissosity (the dominant form surface, S1). Localized high-strain zones (S2) developed during latter stages of the high-grade metamorphic evolution, conditions during which are estimated at ~5 to 6 kbar at temperatures ~ 700º C. The intrusion of north-trending Jetty Granite Dykes (and their subsequent deformation) at ca. 500 Ma occurred at probable upper amphibolite-facies, indicating that an early Palaeozoic event (which reached granulite-facies in Prydz Bay, ~ 200-300 km to the northeast) significantly affected the Jetty Peninsula region. Minor northwest-trending steeping dipping mylonites and vertical north-trending brittle faults cut all rock types, except the massive quartz 'blows' and veins. These quartz pods are locally abundant (e.g. near Soyuz station), and, together with the late brittle faults, are thought to be related to incipient rifting of the Lambert Graben during the breakup of Gondwana.

Numerical models are the primary predictive tools for understanding the dynamic behavior of the Antarctic ice sheet. But a key boundary parameter - the magnitude of sub-glacial heat flow - is controlled by geological factors and remains poorly constrained. We show that variations in the abundance and distribution of heat-producing elements (U, Th and K) within the Antarctic continental crust give rise to regional sub-glacial heat flows as much as 2-3 times greater than previously assumed in many ice modeling studies. Such elevated heat flows would fundamentally impact on ice sheet behaviour and predict higher regional basal melt production, enhanced ice surging and streaming. We also recognize that, prior to the breakup of Gondwana, much of the East Antarctic continental crust was contiguous with southern Australia where extensive high heat-producing Proterozoic-aged rocks, and correspondingly elevated regional heat flows, are well documented and such crustal rocks almost certainly extend beneath the modern east Antarctic ice sheet. Such fundamental geological controls on sub-glacial heat flow must be considered in accurately modeling ice dynamics, permitting more refined predictions of ice mass balance and sea level change and is a particularly relevant issue in the context of anthropogenic climate change.

A short article as a side bar in the Australian Antarctic Magazine published by the Australian Antarctic Division. The sidebar article will accompany a longer article by Lt Peter Waring of the Royal Australian Navy survey team that conducted a multibeam survey in Casey Harbour during season 2013-14

The ca. 1000 Ma Brattstrand Paragneiss in the Larsemann Hills contains a unique assemblage of borosilicate-rich rocks: tourmaline (Tur) quartzite, prismatine (Prs) leucogneiss and grandidierite (Gdd) borosilicate gneiss. In situ analyses with a Cameca ims 4f ion microprobe gave '11B (= {[sample11B/10B / SRM 95111B/10B] - 1} × 1000) to be '3.0 to '14.3? in Tur, '9.6 to '18.1' in Prs and '1.9 to '8.7' in Gdd (1s mostly 1-2' per sample). In anatectic pegmatites, Tur '11B = 4.8 to '12.1'; comparison with host rock Tur implies melting and crystallization from melt together did not fractionate B isotopes. With two exceptions, average '11B increases in a given sample Prs < Tur < Gdd with Prs B 4.8±1.6' lighter and Gdd B 2.8±1.9' heavier than Tur B. This regularity is consistent with the preference of 10B for tetrahedral sites (Prs) and 11B for trigonal sites (Tur, Gdd) and crystallization in near isotopic equilibrium. The precursor of the B-rich rock least changed by metamorphism, Tur quartzite, is interpreted to be a product of pre-metamorphic, hydrothermal B-metasomatism. If there had been no '11B decrease from devolatization during metamorphism, quartzite Tur '11B ('8.7 to '5.7') constrains '11B of premetamorphic fluid to be '3 to 0' (2008 Tur-fluid '11B for 200 C), consistent with a continental source. However, more likely devolatization decreased Tur '11B, and '11B > 0' in the premetamorphic fluid, so an alternative precursor, such as mud volcanoes, should be considered.