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991.
利用南大洋2009—2020年的Argo浮标温盐剖面数据,通过绘制温度和盐度空间分布图的定性分析以及三维聚类可视化分析等方法,揭示了南大洋印度洋扇区的多水团空间分布特征.结果表明,在60°S~67°S,60°E~80°E之间的海域,海水温度在-1.9~2.5℃之间,盐度在32~34.75 psu之间.整个研究区域海水温...  相似文献   
992.
渤海湾西岸天津平原南部静海区400m深CGZ5孔、大港区500m深TPZ1孔岩心的岩石地层、磁性地层、14C测年、微体古生物研究表明,2个钻孔底部分别进入到定年3.6Ma的高斯(Gauss)正极性带和定年4.5Ma的吉尔伯特(Gilbert)极性带上部;位于西侧沧县隆起的CGZ5孔2.58Ma古地磁M/G(松山/高斯,Matuyama/Gauss)极性带界线位于225m,位于东部黄骅坳陷西斜坡的TPZ1孔该界线位于208m;0.78Ma的B/M(布容/松山,Brunhes/Matuyama)极性带界线分别位于55m和68.6m。结合微体化石分析、3期海侵地层的确定以及岩石地层特征,可判断CGZ5孔和TPZ1孔上更新统底板分别位于55m 和63.4m。依据末次盛冰期低水位域潴育化黏土层位,确定全新统分别厚14.8m和16.5m。上述2孔之间的黄骅坳陷板桥主凹陷中CQJ4孔,B/M和M/G界线分别位于74m和340m。西部CGZ5孔显现整个中更新统缺失,东部TPZ1孔中更新统仅厚5.3m。推测这一地层间断可能是由于渤海海盆在中更新世初期发生快速断陷,在河流到海盆的高差加大的背景下,河流输送物大部流入海盆,海盆边缘的沧县隆起和相邻的滨海平原发生了过路作用。在“源到汇”古地理状况变迁过程中形成的东部大平原,中更新世的沉积动力学背景需要进一步研究。  相似文献   
993.
随着东濮地区地热勘探的不断深入,现有奥陶系储集层研究精度已不能满足勘探需求。基于露头、岩心、薄片、测录井、碳氧同位素和流体包裹体等手段,结合区域地质背景,深入研究了东濮地区奥陶系碳酸盐岩成岩系统及其对储集层的影响,并进一步预测了有利储集层的分布区。研究表明,准同生和早成岩期发生胶结、压实、准同生白云石化和准同生溶蚀作用,其中胶结、压实作用使储集层原生孔隙度大幅减少;表生成岩期发生风化壳溶蚀作用,对储集层孔隙的增加起决定性作用;中—晚成岩期发生构造破裂、热液溶蚀、压溶、胶结、埋藏白云石化和重结晶作用,其中白云石化、溶蚀和构造破裂作用对储集空间的贡献最大,重结晶作用具有双重性,对粉细晶白云岩起强烈破坏作用。综合研究将研究区划分出Ⅰ类储集层分布区1个、Ⅱ类储集层分布区2个和Ⅲ类储集层分布区2个。其中,颗粒滩、潮坪与断裂发育带、白云石化、准同生溶蚀、风化壳溶蚀、热液溶蚀作用叠合区储集层质量最佳,多为Ⅰ类和Ⅱ类储集层分布区。  相似文献   
994.
随着油气勘探程度的加深,岩性油气藏的重要性日益显现,而查明油气富集规律是岩性油气藏勘探的关键。渤海湾盆地东营凹陷牛庄洼陷沙三中亚段发育大量岩性油气藏,文章以此为研究目标,着重分析其平面上油气分布的主要控制因素。研究结果表明,牛庄洼陷岩性油气藏的分布受控于洼陷内流体性质、断层作用和沉积相展布3种地质因素。它们对洼陷区岩性油气藏富集规律的影响分别在于:洼陷内流体运聚单元控制着油气在平面上的富集区,牛庄洼陷南北两侧汇聚流发育区是油气聚集的有利地带,而洼陷北部平行流和东西两侧发散流发育区不利于油气成藏;同生断层泵吸作用使得油气在牛庄洼陷平行流和发散流发育区可形成局部汇聚流,从而聚集成藏,断层的侧向遮挡作用则使得牛庄洼陷生成的油气多富集在靠近边界断层的洼陷内侧;物性较好的浊积水道微相最有利于油气的富集,朵叶体和水道间次之,外缘最差。  相似文献   
995.
沂沭断裂带是郯庐断裂带的山东段,该断裂带不仅规模大,而且活动性强,具有"两堑夹一垒"的构造格架。利用实测1:20万海底高精度重力测量数据对沂沭断裂带莱州湾海域重力场特征进行了研究,采用欧拉反褶积、纹理分析等边界识别方法对数据进行处理解释,旨在对研究区进行构造格架的细化。根据重力场特征,推断断裂22条,以NE-NNE向和近EW向为主,推断沂沭断裂带4条主干断裂在莱州湾呈NNE向近平行舒缓波状展布;初步划分了3个三级构造单元,5个四级构造单元,12个五级构造单元;推断昌邑-大店断裂以西重力高反映了基底凸起,重力低主要反映了中、新生代凹陷,断裂以东重力高主要反映了早前寒武纪变质岩分布,重力低主要反映了中生代花岗岩体分布。  相似文献   
996.
《China Geology》2019,2(4):493-500
Due to the unique geographical location and sensitive response to global climate changes, the Antarctic region plays an important role in paleoclimate researches, and attracts great attentions from various scholars. One 324 cm long sediment core (ANT29-P7-09) was obtained from Prydz Bay, Antarctica, during the 29th Chinese National Antarctic Research Expedition. Based on sediment particle size, TOC, δ13C analyses and magnetism data, the authors show that the dominant magnetic minerals are ferrimagnetic pseudo single domain (PSD)-multi domain (MD) magnetite. Variations in the paleoenvironmental records allow us to define 4 zones in the core. These zones outline the climatic variations in the region since the late Early Pleistocene, including a warm period, a transitional period, and a cold period. The magnetic particle assemblage varies with glacial-interglacial cycles. Abrupt changes in particle size, TOC content, and geomagnetism occur at 102–90 cm deep in the core, indicating a sudden warming in the Antarctic region, signaling the onset of the Holocene. The authors identified 3 additional climatic signals in the middle part of the core (232–162 cm) that show unexpected cooling events during the warm period in Prydz Bay, Antarctica.  相似文献   
997.
《China Geology》2019,2(4):522-529
In recent years, development activities have had a significant impact on the environment of the Jiaozhou Bay, China. To ensure the sustainable economic and social development of the Jiaozhou Bay area, it is necessary to strengthen corresponding control measures. The important prerequisite is to properly understand the environmental conditions laws of natural change, especially the dynamic processes of sediment and the characteristics of landform evolution. Based on the data of continuous observation at 6 stations in Jiaozhou Bay for 25 hours, the Hydrodynamic Eutrophication Model (HEM-3D) was used to simulate the sediment erosion and deposition. The results show that the maximum suspended sediment concentration in the sea area of Jiaozhou Bay is about 40 mg/L, which appears in the northwestern area of the bay top and the Cangkou watercourse area, and the low concentration is located in the area of the central Jiaozhou Bay towards the bay mouth. The suspended sediment is 6–10 mg/L. Affected by a decrease in seawater material, the direction of the prevailing current in the Jiaozhou Bay area is different from that of the sediment transport. The velocity of the flood current is higher than that of the ebb current. However, during flood tide, the flux of resuspended seafloor sediment outside and at the mouth of the bay is limited and cannot contribute significantly to the suspended sediment in the bay. During ebb tide, the resuspended sediment at the shallow-water bay head and the east and west sides spreads toward the bay mouth with the ebb current, although it extends beyond the bay through the bay mouth. The research results can provide scientific support for the Jiaozhou Bay project construction and environmental protection.  相似文献   
998.
Variability within the genus Spaniocerca has been studied, and as a result S minor Kimmins has been synonymised with S. zelandica Tillyard. S zelandica is redescribed, the larva is figured, notes on ecology are given, and the nature of the variation found is discussed. Notonemoura cowleyi Winterbourn is transferred to Spaniocercoides Kimmins.  相似文献   
999.
Balaena Bay, Wellington Harbour, New Zealand, has a small pocket beach that was covered originally by pebbles and cobbles. In February and October 1982, the beach was nourished with sandy granular gravel, the stability of which was monitored until February 1984. Although isolated from oceanic swell, the new beach readily responded to locally generated wind waves which induced both northwards and southwards longshore drift. The net effect was erosion of the southern beach, aggradation over the central beach, and minor fluctuations at the northern end. Yet despite this mobility nearly all the nourishment sediment was retained in the littoral zone. Beach volumes, calculated for each survey, varied little and sediment distribution patterns revealed negligable transport of nourishment sediment to adjacent beaches and offshore areas. Stability is further confirmed by compositional data which record no preferential loss of the sandstone, argillite, and quartz components. The only compositional changes were the incorporation into the new beach of small (< 10%) quantities of sediment derived from the old beach surface and from biogenic productivity.  相似文献   
1000.
Grow-out studies of the scallop Pecten sulcicostatus, endemic to the South African coast, contribute to an investigation of the suitability of this species for commercial culture. Hatchery-reared juvenile scallops were placed in a suspended culture system at 5 m depth in Saldanha Bay on the west coast of South Africa. Scallops of 78 days old and ranging in size from 4.5 mm to 11.0 mm shell height (mean 6.9 mm), as measured on 2 February 2010, were deployed in Saldanha Bay on 9 February 2010. Subsequent growth was assessed monthly through increments in shell height in relation to changing environmental conditions as determined through continuous measures of temperature and chlorophyll a. Upon termination of the experiment on 15 February 2011, scallops ranged in size from 42.1 mm to 48.7 mm (mean 45.1 mm), representing an increment in shell height of 38.2 mm over one year. The mean growth rate of 0.10 mm day?1 (mean specific growth rate of 0.0046 day?1) compares favourably with other commercially cultured species and exceeds previous estimates of growth of naturally occurring populations of P. sulcicostatus. Scallop growth was poorly correlated with either temperature or chlorophyll a concentration, but scallop mortality was closely aligned to the temperature regime of Saldanha Bay, exhibiting high mortalities during mid-summer.  相似文献   
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