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[1] Isotopically dated corals from the central New Hebrides and New Georgia Island Group, Solomon Islands, indicate that both forearcs underwent rapid late Quaternary subsidence that was abruptly replaced by hundreds of meters of uplift at rates up to ~8 mm/yr, while total plate convergence was only a few kilometers. Two mechanisms that might account for these rapid reversals in vertical motion include (1) a 'displacement' mechanism in which the forearc is displaced upward by the volume of an object passing beneath on the subducting plate (as the object moves deeper and vacates the base of the forearc, the forearc subsides to near its original position) and (2) a 'crustal shortening' mechanism in which the forearc thickens and uplifts because of horizontal shortening when a large object impinges on the forearc and abruptly increases interplate coupling on the shallow end of the main thrust zone. Rapid subsidence follows when the impinging object is broken or otherwise decoupled, shallow interplate coupling becomes weak, and the uplifted forearc extends and subsides. The displacement mechanism surely plays a role on timescales over which plates converge tens of kilometers, but it fails to explain the geographic pattern, short time frame, and abruptness of the change from subsidence to uplift that we observe. The crustal shortening mechanism is preferred because it allows the observed abrupt uplift when an object impinges on a forearc and causes locking of a shallow segment of the interplate thrust zone. Citation: Taylor, F. W., et al. (2005), Rapid forearc uplift and subsidence caused by impinging bathymetric features: Examples from the New Hebrides and Solomon arcs, Tectonics, 24, TC6005, doi:l0.1029/2004TC001650.

The study presents a summary of the latest data on ostracod microfaunas from Middle–Upper Holocene lacustrine deposits of southern West Siberia collected from lakes Malye Chany, Bol’shaya Lozhka, Beloe, and paleolake Chicha. A total of 28 ostracod species were identified. The identified ostracod assemblages reveal local variations in the lake ecosystems as well as general trends, which can be correlated with both regional and global climate changes. A cooling episode during the second half of the Subboreal is marked by the transition from a warm-water mesohaline assemblage to cold-water candonid ostracods at ca. 3.4 cal ka BP. The widespread occurrence of mesopolythermophilic ostracod species at 1.9–0.6 cal ka BP indicates the end of cooling and lowering of lake-water level. From 0.6 cal ka BP to present, the ostracod assemblages area characterized by the high specific diversity, which is probably an indication of the increased variability of aquatic ecosystems due to fluctuations in salinity and water levels of the lakes. Climate changes identified by ostracod assemblages are consistent with the climatic trend constrained by early palynological studies. [ABSTRACT FROM AUTHOR]

Abstract: Pottery tempered with rice chaff from the early Iron Age cemetery of Ban Non Wat site, northeast Thailand, has been subjected to direct AMS 14C dating, using low temperature combustion with oxygen as originally developed by authors. The carbon yield (0.2–0.5%) testifies the suitability of this pottery for dating. However, not all the results are in agreement with expected archaeological ages and other 14C dates from the studied site and neighboring site of Noen U-Loke. This calls for a thorough analysis and interpretation of pottery temper dates from the region. [Copyright &y& Elsevier]