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Manoj Chopra 《国际地质力学数值与分析法杂志》1995,19(6):453-454
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Concentrations of iron sulphide minerals in sediments within and adjacent to a small intertidal thermal pool near Talasea township are forming and being modified under a wide range of exhalative-sedimentary conditions. A geochemical, mineralogical and bacteriological investigation of these iron sulphides has defined the major reactions leading to their formation and indicated aspects in which their mineralogies, textures and mechanisms of formation differ significantly from those of iron sulphides formed under “normal” sedimentary conditions. The main features of the thermal pool environment are: 1. the occurrence of relatively high iron sulphide concentrations; 2. the preservation, by the strongly anaerobic thermal spring waters, of hydrotroilite formed in the thermal pool sediments in the presence of excess sulphide; 3. the presence in the pool banks of major marcasite (which appears to replace its dimorph pyrite) formed as a result of the development of strongly acidic conditions; 4. the abundance in the pool banks of large euhedral crystals of pyrite and marcasite, and the scarcity of framboids; 5. the presence of sulphate-reducing bacteria in the thermal waters and sediments. 相似文献
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《第四纪科学杂志》2008,23(1):no-no
Journal of Quaternary Science Published online 9 August 2007. DOI: 10.1002/jqs.1118 The above paper was incorrectly titled. The correct title should be: Comment: Middle Pleistocene sedimentation at Pakefield, Suffolk, England J. R. LEE, J. ROSE, I. CANDY and R. W. BARENDREGT (2006) Journal of Quaternary Science 21 : 155–179 The error will be corrected prior to print publication. 相似文献
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STUART D. LUDLAM 《Sedimentology》1981,28(1):85-96
In Fayetteville Green Lake, past sedimentation rates can be accurately and precisely estimated by separating annual couplets or varves in dried sediment samples. Two measures were used, which serve as upper and lower limits on estimated sedimentation rate. They agree within 5 % with average annual sedimentation rate in couplets for recent years. Between 3 and 5 replicate samples are needed to reduce the half-width of 95 % confidence intervals on individual couplet sedimentation rates to 30 g m?2 yr?1 about 5 % of average recent rates. In the late 1800s sedimentation rate averaged 392 g m?2 yr?1 and ranged between 324 and 466 g m?2 yr?1, while in the 1970s the rate averaged 581 g m?2 yr?1 by the same measure, and ranged between 384 and 646 g m?2 yr?1. Sedimentation rate averaged for 13 years does not vary over short distances in the profundal zone, but lateral variation in sedimentation rate can be detected for individual years over the same distance. Not all this variation was associated with the non-uniform distribution of dark sublaminae and thin turbidites which cannot be separated from the annual layers. This indicates that although precise estimates of sedimentation rates can be made at different points in the lake, estimates will have to be made at numerous points before annual sedimentation rates for the lake as a whole can be accurately assessed. 相似文献