Paleomagnetism of the triassic nicola volcanics and geotectonics of the quesnellia subterrane of terrane I, British Columbia

Paleomagnetic data from 46 sites (674 specimens) of the Westcoast Crystalline Gneiss Complex on the west coast of Vancouver Island using AF and thermal demagnetization methods yields a high blocking temperature WCB component (> 560°C) with a pole at 335°W, 66°N (δ_p = 4°, δ_m = 6°) and a lower coercivity WCA component ( 25 mT, < 500°C) with a pole at 52°W, 79°N (δ_p = 7°, δ_m = 8°). Further thermal demagnetization data from 24 sites in the Jurassic Island Intrusions also defines two high blocking temperature components. The IIA component pole is at 59°W, 79°N (δ_p = 7°, δ_m = 8°) and IIB pole at 130°W, 73°N (δ_p = 12°, δ_m = 13°). Combined with previous data from the Karmutsen Basalts and mid-Tertiary units on Vancouver Island and from the adjacent Coast Plutonic Complex, the geotectonic motions are examined for the Vancouver Island segment of the Wrangellian Subterrane of composite Terrane II of the Cordillera. The simplest hypothesis invokes relatively uniform translation for Terrane II from Upper Triassic to Eocene time producing 39° ± 6° of northward motion relative to the North American craton, combined with 40° of clockwise rotation during the Lower Tertiary.     

Geochemical characteristics and LA-ICP-MS zircon U-Pb age of the Lanhualing granite in Ningguo,Anhui ProvinceEI北大核心CSCD

The Lanhualing tungsten-molybdenum deposit is a skarn-type deposit located in Ningguo county, Anhui province. This deposit is mainly hosted in the Yinzhubu Formation and the Yanwashan Formation of Ordovician, and genetically related to the Lanhualing granite. The Lanhualing granite belongs to high-K calc-alkaline series with high alkali (Na2O+K2O=4.00%-7.03%), SiO2 (67.87%-74.92%) and MgO (0.62%-1.23%) contents. The granitic rocks show right-dipping chondrite normalized REE patterns with weak δEu anomalies. The granitic rocks are relatively enriched in large ion lithophile elements (LILE) and depleted in high field strength elements (HFSE). The ore-bearing granite was dated at 148.17±0.94 Ma by LA-ICP-MS zircon U-Pb method. The late Yanshanian is the main tungsten mineralization epoch in the South Anhui-north Jiangxi area; and indeed, the Dongyuan, Zhuxi, Yangchuling, Dahutang and other large and super-large tungsten deposits were formed in this period. Geochemical Characteristics of the Lanhualing granite indicate a crustal source but with mantle input under tectonic regime of compression thickening. ©, 2015, Science Press. All right reserved.     

The Quaternary Lancaster Sound trough‐mouth fan,NW Baffin Bay

The development of the Lancaster Sound Trough Mouth Fan (TMF) and glacial history in Arctic Canada were studied using a high‐resolution seismic profile across the entire fan and two piston cores. Stacked tills separated by erosion surfaces on the shelf pass seaward through till deltas into thick transparent glacigenic debris flow (GDF) deposits on the slope, separated by thin, well‐stratified glaciomarine layers. An age model was built by ties to the Ocean Drilling Program Site 645. The deepest GDF on the seismic profile was indicative of the onset of shelf‐crossing glaciation in the Early Pleistocene. The transition of the growth of Lancaster Sound TMF from an aggradational sequence (unit M) to an aggradational–progradational sequence (unit F) occurred at the Middle Pleistocene transition in glacial cyclicity. In the most recent glacial cycle, GDF sheets were deposited during Heinrich events 4 and 2 according to the correlation of the main detrital carbonate beds in two piston cores. The outmost till wedge reflects the maximum advance of the grounding glacier, far seaward of previously proposed Last Glacial Maximum ice extent. Copyright © 2011 John Wiley & Sons, Ltd.     

A summary of environmental issues and findings: Tennessee-Tombigbee Waterway

The enactment of the National Environmental Policy Act (NEPA) had a substantial influence on the manner in which the Tennessee-Tombigbee Waterway (Tenn-Tom) was constructed The interdisciplinary approach, including a board of outside consultants functioning as environmental advisors, played a valuable role toward meeting the objectives of minimizing adverse impacts and maximizing the positive environmental aspects Several of the key environmental issues associated with the Tenn-Tom are addressed and the findings are presented impacts addressed include aquifer drawdown, waterlogging, water quality, interbasin transfer, mixing of species, endangered species, erosion, sedimentation, and loss of wildlife habitat Additional discussion is also presented to explain the findings and place the identified impacts into perspective While implementation of the Tenn-Tom involved losses and resource tradeoffs, measures have been incorporated into the project to mitigate for significant resource losses The evaluation, planning, and design process for the Tenn-Tom can serve as a model approach for compliance with NEPA and other environmental statutes     

Monte Verde,South-Central Chile: Stratigraphy,climate change,and human settlement

Two sedimentary units are recognized by means of stratigraphic and sedimentological analyses at Monte Verde, a late Pleistocene archeological site with stone tools and well-preserved wood artifacts and botanical remains, that lies southwest of Lago Llanquihue and north of the Golfo de Reloncavi in the southern end of the Chilean Central graben. the geological evidence shows that at no time after 33,000 yr B.P., and perhaps since the first Llanquihue advance (before 56,000 yr B.P.), was the Monte Verde area covered by ice. Influences of two glacial advances at 20,000 and 15,000-14,500 yr B.P. are recognized at the site; effects of the Varas Interstade, however, are not identified. Rapid climatic change took place after the end of the Llanquihue Glaciation. It was shortly interrupted by a cool, wet period around 10,000 yr B.P., after which a well-documented Hypsithermal (8270-4750 yr B.P.) accompanied by pyroclastic vulcanism followed. The evidence indicates that around 13,000 yr B.P. 1) the site occupants settled on the sandy point bars and beaches of the old creek channel and 2) the area was habitated during cool and wet conditions similar to those that prevail in the area today. Evidence for reconstruction of the paleo-environment and climate of the terminal Pleistocene and the preliminary implications of these findings for understanding the human occupation at Monte Verde are discussed.