The Amer Belt, hosting eleven informal formations of the supergroup, is proposed as type area for four regional Paleoproterozoic sequences (Ps1–Ps4) in central Rae Craton, western Churchill Province. ca. 1.9–1.865 Ga Snowbird orogeny (D P1 ) affected only Ps1–Ps3, whereas 1.87–1.81 Hudsonian P2 all four. Sequence Ps1 Ayagaq Lake formation (<2.3 quartzite) initiates schistose basal polymict o...

argillite, interbedded basalt and abundant diabase sills. More specifically, the rhodonite is located above a section of grey, black and pale green chert and argillite at the base of the unit [IIPPvs( I ) on Figure 2-15-21 and about 50 metres below an upper section of brightly coloured, maroon, red, green and grey chert and argillite [Unit IIPPvs(2) on Figure 2-15-21, This stratigraphic positio...

The 1285 m thick MIS core offers an invaluable opportunity to obtain a detailed record of volcanism in McMurdo Sound. Volcanic stratigraphy and preliminary petrologic data on volcanic rocks in the AND-1B core are reported here. Remarkable volcanic deposits include: a) a phonolitic pumice layer found at ≈85 mbsf which is not correlated to any known vent onshore; b) a black well sorted volcanic s...

[1] High-resolution images of the walls exposed in Valles Marineris reveal variations in appearance and degree of layering indicating various lithologies comprise the Tharsis plateau. The layered wall rock has been proposed to result from effusive flood basalt volcanism or interbedded sediments and volcanics. We present observations of unlayered rock that indicate layering extends to a greater ...

Soil degradation, including rocky desertification, of the karst regions in China is severe. Karst landscapes are especially sensitive to soil degradation as carbonate rocks are nutrient-poor and easily eroded. Understanding the balance between soil formation and soil erosion is critical for long-term soil sustainability, yet little is known about the initial soil forming processes on karst terr...

We present a glacial record from the western Olympus Range, East Antarctica, that documents a permanent shift in the thermal regime of local glaciers, from wet to cold based, between 14.11 and 13.94 million years ago (Ma). The record includes classic wet-based tills interbedded with fossil-rich glaciolacustrine deposits overlain by a series of cold-based drifts. Chronologic control comes from A...

ANDRILL completed its first season in 2006-07 drilling AND-1B through the McMurdo Ice Shelf (MIS) to a depth of 1,285m below the sea floor, a record for Antarctic margin drilling, with 99% recovery. The alternating glacial-interglacial sediment packages interbedded with volcanics provide a uniquely detailed record of Antarctic glacial and climatic change through the Neogene. This paper summariz...

Based on the latest laboratory test and prospect well data of G layer in south depression of D basin, the source rock、reservoir、cap-rock and preservation forming condition of tight oil and gas within research area is analyzed. The results indicate that the widely distributed dark mudstone of J layer has rather high organic content .IIb and III types are the mainly genetic types of organic matte...

In a recent issue of PNAS, Zheng et al. (1) report a “Late Oligocene–Early Miocene age” of the Taklimakan Desert in northwest China. Their age was based on Ar/Ar dating of biotites and U–Pb dating of zircons from layers within the Xiyu Formation, which they interpreted as “volcanic ash.” This chronology effectively extends the formation of the Taklimakan Desert from ∼5 Ma, as recently reported ...

The eastern part of the Adelaide Geosyncline contains well preserved glaciomarine sequences of the Sturtian glaciation (:750–700 Ma) including calcareous or dolomitic siltstone, manganiferous siltstone, dolostone and diamictite units and the associated Braemar ironstone facies. The ironstone facies occurs as matrix to diamictites and as massive to laminated ironstones and comprises abundant Fe ...