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141.
Abstract Rocks from Karaginsky accretionary prism (Karaginsky Island, Bering Sea) yield both prefolding (close to original) and postfolding magnetic vectors. The prefolding vectors suggest that the Maastrichtian–Paleocene volcanic–terrigenous sequences of Karaginsky Island formed at approximately 40°N to 50°N ( n = 45, D G = 325, I G = 57, K G = 6, α95G = 8, F G = 15.06, D S = 332, I S = 63, K S = 20, α95S = 4.5, F S = 0.3297, F cr = 2.64) and were not originally part of either Eurasia ( F = 19, Δ F = 6.5) or North America ( F = 17, Δ F = 4.4). The geologic blocks rotated insignificantly counterclockwise about the horizontal plane, suggesting that the structure of Karaginsky Island arose without major strike-slip motions. Analysis of secondary magnetizations (for example, n = 28, D G = 311, I G = − 50, K G = 9, α95G = 8.7, F G = 2.44; D S = 293, I S = − 41, K S = 5, α95S = 11, F S = 12.04, F cr = 2.65) reveals that the development of this framework involved at least two stages of deformation. During the second stage the sequences must have been tilted to west-northwest and northwest directions at 45–65°. This agrees with the northwest vergence of the structure of Karaginsky Island. 相似文献
142.
143.
在台风风暴增水过程中,风应力占主要作用,气压项的作用要上对较小,许多风暴潮预报模式中气压项被忽略。本文在建立台湾海峡风暴潮预报模型的基础上峄台风气压项作用进行了模拟,结果发现在台湾海峡狭长的海域内,台风气压项的作用表现得较为特殊,在台风风暴潮模拟过程中,应考虑其贡献及大小。 相似文献
144.
INTRODUCTIONTheattentiontothestudyofmetalsinthemarineaerosolparticulatesisincreasingduetotheirenvironmentalecologicaleffectsandcontributiontothebiogeochemicalcycle.Intheaspectofenvironmentalecologicaleffects,first,onthesideofclimate,aerosolswithmetalscanactascloudcondensationoricenuclei,absorbandscattersolarradiation,andaffecttheradiationbudgetontheearth.Therelativelyhighironcontent(5%)ofthedustcanabsorbtheshortwavelengthradiationefficiently.Second,onthesideofecologicaleffects,di~lvedAlse… 相似文献
145.
I~IOWDuceetal.(1980)calculatedthattheair-seaexchangeprocesscouldsupply80%--90%ofthediforedironinputtothephotcrzoneoftheSargassoAsfromairand16%--76%tothecentralNorthPacific.CuisessentialtotheTnarineorganisms,butexcessiveCuistoxictOtheOrganisms.CdandPh... 相似文献
146.
台湾海峡北部海区浮游动物的分布和群落划分 总被引:3,自引:0,他引:3
1994年8月(夏季)和1995年2月(冬季),对25.00-26.50°N,122.00°E以西水域的浮游动物进行了2个航次调查。结果表明,非胶质浮游动物总生物量有明显的季节变化,夏季生物量为冬季的5.88倍。夏季的浮游动物总生物量和群落多样性(H')均较丰富,这和多个水团在此交汇有关。通过聚类分析,两个季节都存在两个不同的群落,群落生活小区的位置有明显的季节变化。夏季的两个暖流水群落和冬季台湾海峡混合水群落的H'值高和比较高,浙闽沿岸水群落的H'值低。 相似文献
147.
Based on the output data from 1997 to 2000 obtained by the MITgcm's (general circulation model) adjoint assimilation method, volume, heat and salt transports through the Luzon Strait are calculated. The results indicate that there are obvious different characteristics between 1997 and 1998~2000 on the transports through the Luzon Strait. During 1997, theLuzon Strait had a mean net westward transport of 3.93×106 m3/s with a maximum transport of 7.34×106 m3/s in October. During 1998~2000, the Luzon Strait possessed an annual mean eastward transport of 0.93×106, 1.80×106 and 1.00×106 m3/s respectively with a maximum eastward transport of 4.10×106/3.31×106 m3/s in July 1998/1999 and 2.06×106 m3/s in April 2000, respectively. Moreover, the transports in 1997 indicated a difference from the other years, i.e.,that the ranges of westward inflows expanded more obviously to north of the Luzon Strait and downwards exceedingthose of the other years. The westward inflows expanded horizontally to the north part of the Luzon Strait until 21°N. 相似文献
148.
白令海北部陆坡B2 9柱状样中放射虫Cycladophoradavisiana含量曲线和深海SPECMAP氧同位素记录的对比 ,为该柱状样建立了晚第四纪约 1 0万年以来的地层年代框架。该柱状样中微体化石、碳屑颗粒、筏冰碎屑 (石英和岩屑颗粒 )的定量分析结果表明 ,作为表层生产力指标的粗组份自氧同位素 5 .3期以来呈阶梯状增加 ,反映表层生产力阶段式的增长 ;碳屑颗粒丰度自氧同位素 5 .3期至末次冰消期的增加说明白令海末次冰消期以前气候较全新世干冷 ,天然火灾发生的概率较全新世大大增加 ;冰期和早、中全新世较高的筏冰碎屑反映了冰期和早、中全新世白令海陆架海冰的扩大以及气候转暖所导致的海冰消融的过程 ,揭示了白令海对过去全球气候变化的响应。 相似文献
149.
基于台湾海峡西部新采集的高分辨率二维地震资料及钻井数据,结合区域地质资料和前人研究成果,建立台湾海峡西部高精度等时地层格架,在此基础上厘定了地质年代属性和沉积相特征分析。研究表明第四纪地层识别出6个三级层序界面,对应地划分为5个三级层序。研究区地震相主要有席状平行—亚平行地震相、前积地震相、下切谷充填地震相、充填状低连续地震相和充填状杂乱地震相等,不同的地震相及其组合代表特定的沉积体系。通过以上分析可知研究区新生代主要发育于海陆过渡地带,主要发育冲积/洪积平原相和滨岸平原相,在此基础上分析沉积演化特征,为台湾海峡西部海域进行精细勘探提供地质依据,这对将来的油气勘探具有重要的指导意义。 相似文献
150.
Twelve 1–2 m, 10-cm-diameter gravity cores collected in 1988 and 1991, from the continental shelf and fjords of East Greenland near Kangerlussuaq Fjord/Trough (ca. 68°N, 32°W), have distinct changes in lithofacies and in the quantity of iceberg rafted (IRD) sediments. These changes are readily observed in X-radiographs of the split cores. We quantify the IRD contribution through grain-size analyses and counting the number of clasts >2 mm from the X-radiographs. Chronological control is provided by acclerated mass spectroscopy 14C dates on foraminifera. During deglaciation, after 14 cal.ka there was one interval of IRD accumulation ca. 12–13 cal.ka, followed by a brief return to IRD conditions centred at 9 cal.ka. Thereafter, a prominent feature of most cores on the shelf is an increase in IRD accumulation that started ca. 5–6 cal.ka, and which has increased toward the present. Indicators of iceberg rafting, such as the net sand flux and numbers of clasts >2 mm ka−1, follow a power law distribution when graphed against distance from the present East Greenland coast, a measure of the position of the glacier margins. The form of the relationship indicates that there is a dramatic decrease in the supply of sediment from the fjords to the shelf. These relationships are used to estimate changes in the location of the ice margin during the late Quaternary based on a site on the East Greenland slope, Denmark Strait, and to discuss factors that can negate such a simple transfer function. © 1997 by John Wiley & Sons Ltd. 相似文献