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CHRIS W. LEE 《Geology Today》1991,7(4):133-136
Each year many hundreds, if not thousands, of Earth-science students visit the coastline at Ogmore-by-Sea, mid-Glamorgan. They study the excellent exposures of Lower Carboniferous Limestone, with their well-preserved coral and other shelly faunas, together with the presumed late Triassic 'breccias'* that rest unconformably on top. A study of the cements within the breccias may give an insight into syndepositional mineralization and the formation of sedimentary basins linked to the opening of the Atlantic in early Mesozoic times. 相似文献
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Sustainability: A View From The Paddock 总被引：1，自引：0，他引：1
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Crustal Contamination and Fluid-Rock Interaction during the Formation of the Platreef, Northern Limb of the Bushveld Complex, South Africa 总被引：4，自引：0，他引：4
The Platreef is the main platinum group element (PGE)-bearingfacies of the northern limb of the Bushveld complex, but unlikethe Merensky Reef of the eastern and western limbs, it is indirect contact with the country rock. Mineral separate 相似文献
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U-series Isotope Data on Lau Basin Glasses: the Role of Subduction-related Fluids during Melt Generation in Back-arc Basins 总被引：6，自引：2，他引：6
PEATE DAVID W.; KOKFELT THOMAS F.; HAWKESWORTH CHRIS J.; VAN CALSTEREN PETER W.; HERGT JANET M.; PEARCE JULIAN A. 《Journal of Petrology》2001,42(8):1449-1470
New thermal ionization mass spectrometry U-series disequilibriumdata are presented for 24 basaltic to dacitic glasses from activespreading centres in the back-arc Lau Basin (SW Pacific), togetherwith additional inductively coupled plasma mass spectrometrytrace element analyses and Sr–Nd–Pb isotope data.Valu Fa Ridge samples, adjacent to the arc front, have highU/Th and (230Th/238U) <1, implying a recent (<<350ka) addition of a U-rich slab-derived fluid. The Valu Fa datacan be combined with existing 230Th–238U data for theCentral Tonga arc to infer a fluid addition event at 相似文献
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KARI GRØSFJELD SVEND FUNDER MARIT-SOLVEIG SEIDENKRANTZ CHRIS GLAISTER 《Boreas: An International Journal of Quaternary Research》2006,35(3):493-520
Marine sediments from river sections in the Mezen River drainage, northwest Russia, have been analysed for dinoflagellate cysts, foraminifers and molluscs. The sediments were dated by pollen analysis and by reference to the local sea-level history, and are Late Saalian to late Eemian (c. 133 to 119.5 kyr in age). The Late Saalian deglaciation was characterized by Arctic conditions, but a few centuries into the Eemian the Gulf Stream system carried warm Atlantic water into the region. At 129.8 kyr BP there was a marked increase in the influx of Atlantic water, and the advection of warm Atlantic water was stronger and probably penetrated further eastwards than at present. The molluscs, dinoflagellate cysts and foraminifers reflect conditions warmer than present and that the optimum temperature occurred at the time of the early Eemian global sea-level rise. Around 128 kyr BP, the eustatic sea-level rise was curbed by isostatic rebound and accompanying regression and constriction of marine passages to the White Sea. Local, low-saline, stratified basins developed and characterized the next five to six millennia. 相似文献
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The decision in 1988 by the Rangitikei-Wanganui Catchment Board to allocate flows away from use for electricity generation into recreation use brought into focus the conflict between market and non-market valuation of river uses. The travel cost method (TCM) of non-market valuation is used to estimate the in-stream recreation values of the Upper Wanganui and Whakapapa rivers. 相似文献
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ABSTRACT. Numerous avifauna species face extinction on New Zealand's two main islands, owing largely to forest clearance and to introduced mammals. In response, New Zealand selects certain offshore islands for the relocation of threatened native birds, first purging them of mammalian predators. Over the past few decades, this procedure has evolved to become fairly successful. Protected habitat “islands” within mainland forested areas are also being created, but with success less certain. As historic habitats are lost, small biopreservation islands may become a standard mechanism for protecting threatened species, a process that can be termed the “miniaturization” of nature. 相似文献