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51.
Biochemical mechanism of forming the red tide is discussed in this paper.The existence of a large number of nitrates and phosphates in the eutrophic water is the prerequisite of explosive increase of algae and the forming of red tide.Reduction of eutrophication is an important approach to preventing the red tide.The method of deep treatment of the waste water and its denitrification and dephosphorization are introduced,and a new opinion on the red tide formation and fundamental prevention is put forward.  相似文献   
52.
厄尔尼诺(El Ni(?)o)现象是海-气耦合系统异常变化的表现,其起因可能不是唯一的,行星运动对地球运动的影响可能会导致El Ni(?)o的发生。根据4个半世纪内El Ni(?)o发生的历史资料,分析其发生和行星运动的关系,得出的结论是:木星赤纬的变化和火星大冲与El Ni(?)o。的发生有显著的关系,表明这2颗行星的运动可能影响El Ni(?)o的发生。文中还根据分析结桌和El Ni(?)o混沌机制的观点,探讨了行星运动对海-气系统变化的影响机制。  相似文献   
53.
Continental collision between Iranian and Arabian plates resulted in the formation of the Zagros fold–thrust belt and its associated foreland basin. During convergence, pre-existing faults in the basement were reactivated and the sedimentary cover was shortened above two different types of basal decollement (viscous/frictional). This led to heterogeneous deformation which segmented not only the Zagros fold–thrust belt but also its foreland basin into different compartments resulting in variation in facies, thickness and age of the sediment infill.Based on this concept, a new tectono-sedimentary model is proposed for one of the most important syn-tectonic sedimentary unit, the Gachsaran salt in the Zagros foreland basin. In this proposed model, it is argued that differential propagation of the deformation front above decollements with different mechanical properties (viscous versus frictional) results in along-strike irregularity of the Zagros deformation front whereas movement along pre-existing basement faults leads to development of barriers across the Zagros basin. The irregularity of the deformation front and the cross-basin barriers divided the Zagros foreland basin into six almost alternating sub-basins where Gachsaran salt and its non-salt equivalents are deposited. In the salt sub-basins, two different processes were responsible for the deposition of Gachsaran salt: (1) evaporation, and (2) dissolution of extruding Hormuz salt and its re-precipitation as Gachsaran salt. Re-precipitation was probably the most significant process responsible for the huge deposit of Gachsaran salt in the extreme south-east part of the Zagros foreland basin.  相似文献   
54.
西藏崩错8级地震地表破裂的变形特征及其破裂机制   总被引:7,自引:2,他引:5       下载免费PDF全文
1951年11月18日,西藏那曲崩错附近发生了一次8级地震,地表产生了长达约91公里的破裂带。本文总结了该破裂的几何、位移分布特征,讨论了破裂的形成机制和崩错地震的发震构造条件  相似文献   
55.
To look for gas hydrate, 22 multi-channel and 3 single-channel seismic lines on the East China Sea (ECS) shelf slope and at the bottom of the Okinawa Trough were examined. It was found that there was indeed bottom simulating reflector (BSR) occurrence, but it is very rare. Besides several BSRs, a gas seepage was also found. As shown by the data, both the BSR and gas seepage are all related with local geological structures, such as mud diapir, anticline, and fault-controlled graben-like structure. However, similar structural "anomalies" are quite common in the tectonically very active Okinawa Trough region, but very few of them have developed BSR or gas seepage. The article points out that the main reason is probably the low concentration of organic carbon of the sediment in this area. It was speculated that the rare occurrence of gas hydrates in this region is governed by structure-controlled fluid flow. Numerous faults and fractures form a network of high-permeability channels in the sediment and highly fractured igneous basement to allow fluid circulation and ventilation. Fluid flow in this tectonic environment is driven primarily by thermal buoyancy and takes place on a wide range of spatial scales. The fluid flow may play two roles to facilitate hydrate formation:to help gather enough methane into a small area and to modulate the thermal regime.  相似文献   
56.
Jiyang (济阳) sag is an oil rich basin,consisting of Huimin (惠民),Dongying (东营),Zhanhua (沾化),and Chezhen (车镇) depressions.The elastic rock of Paleogene has undergone early and middle diagenetic stages and now the main clastic reservoir is in the middle diagenetic stage.Primary and secondary pores are developed in Paleogene sandstone,the latter is generated from the dissolution of feldspar and calcite cement in rocks owing to the organic acid from the maturated source rock,but the materials dissolved are different in different depressions.The reservoir secondary pores of Dongying depression are generated from the dissolution of calcite cement,the ones of Zhanhua and Huimin depressions from the dissolution of feldspar,the secondary pores of Chezhen depression from the dissolution of feldspar in upper section,and the dissolution of calcite cement in the lower section of Paleogene,respectively.The secondary pores are developed in two depths and the depth goes down from west to east,from south to north in Jiyang sag.The major controlling factors for secondary pore development are maturity and location of source rock.Lastly,the favorable reservoirs are evaluated according to reservoir buried depth,sedimentation,and diagenesis.The reservoir with high quality is located in the northern and central parts in Dongying depression; there are some good reservoirs in Gndao (孤岛),Gudong (孤东),and Gunan (孤南) areas in Zhanhua depression,and the favorable reservoirs are located in the north steep slope and the south gentle slope of Chezhen depression and central uplift,south gentle slope of Huimin depression.  相似文献   
57.
论述了氢化物形成的普遍性、氢化物的物理化学性质、元素周期系各类元素的氢化物类型。认为一些金属离子、非金属离子在酸性介质中与硼氢化钾(钠)作用及金属锌等强还原剂作用生成氢化物。综述了氢化物的形成在分析测试领域的应用:试样分解、分离富集、容量分析、光度分析、原子光谱分析、质谱分析。  相似文献   
58.
镇泾地区延长组河流相砂体分布与圈闭形成的关系研究   总被引:3,自引:1,他引:2  
鄂尔多斯盆地镇泾地区侏罗系地层以三角洲-湖泊沉积体系为主,研究区范围内主要发育主河道和部分分流河道砂体。研究区构造平缓,主要为单斜地层、在东南部存在大型鼻状构造。通过对主要储层段(长6、8油层组)砂体分布及与构造之间关系进行研究,分析砂体走向与构造线方向的关系认为在构造单斜地区,当两者相交时(交角β≠0)是形成圈闭的关键因素之一,在大型鼻状构造地区因构造线的弯曲与河道砂体组合可以形成圈闭。根据研究区砂体分布和构造线组合出4种地层-岩性及岩性圈闭。利用构造图与砂体分布图对主要储层段存在的圈闭确定出长6、8油层组10个层圈闭。  相似文献   
59.
CSAMT法在松辽盆地伊胡塔地区嫩江组中的定位应用   总被引:1,自引:1,他引:0  
上白垩统嫩江组不仅是松辽盆地南部重要的生油层系,而且在本区砂岩型铀成矿中也起着非常重要的作用。从ZK4孔的方法过井测深试验以及地电结构的对比分析入手,对探区内嫩江组的空间分布范围进行了分析研究,通过钻探施工,证实了CSAMT法应用的有效性。  相似文献   
60.
A new species of Araucaria, Araucaria beipiaoensis sp. nov., collected from the Middle Jurassic Tiaojishan Formation, southern hill of Shebudai village, near Beipiao city, western Liaoning is based on a permineralized female cone, which is ovate to elliptical in shape, about 11 cm × 7 cm × 4.5 cm in size. The cone bears rhomboid bracts that are spirally attached, texture thicker, with wings on both sides, with a detached lamina-like apex at the tip. In inner structure the ovuliferous scales are thicker and fused with bracts at the end with a ligular sulcns. There is one wingless ovule/seed per seed-scale complex embedded in the ovuliferous scale tissue, with the micropyle directed toward the cone axis. The ovules/seeds are long ovate or elliptical in shape, 1 cm long and near the base about 3 mm in diameter; the ovule/seed integuments have begun differentiation into 3 layers: the sarcotesta, sclerotesta, and endotesta. The nucellus is free from the enclosing integuments except in the chalazal region where it is fused to the inner layer (endotesta) of integument. Some ovules show cellularized nucellar tissue. Mature seeds exhibit the papery-thin wavy nucellus characteristically near to the micropyle. The embryonic tissue appears to be four cotyledons. The morphology and structure of the cone shows a close relationship to the araucarian cones of fossil and living genera but differs from any known species. The new species is distributed in the Middle Jurassic of the northern hemisphere, especially Asia, and has important significance for the evolution of the Family Araucariaceae.  相似文献   
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