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21.
通过大厂锡多金属矿床多种测温方法测试结果的分析,确定该矿床主要的成矿温度为300±30℃,并进一步推算出其成矿压力为84.2×10  相似文献   
22.
盲断裂、褶皱地震与新疆1906年玛纳斯地震   总被引:31,自引:18,他引:31       下载免费PDF全文
1906年玛纳斯7.7级地震时沿准噶尔南缘断裂产生的地表破坏是由非构造成因的振动和重力效应而形成的。天山山前第二排逆断裂和褶皱带是这次地震的发震构造,沿带已发现了长约130km的断续的地表破裂和最新隆起带。所以1906年玛纳斯地震是沿北天山主逆断裂带发生在深部的一次盲断裂地震。地表变形主要以褶皱隆起为主,是一次典型的“褶皱地震  相似文献   
23.
保山金厂河铜多金属隐伏矿综合找矿   总被引:7,自引:3,他引:7  
综合分析区域地质、磁法、化探、重力资料及相临矿区岩石矿石电、磁性特征基础上,通过靶区优选,提出金厂河磁异常具有寻找大型多金属硫化物矿床的前景。经1:1万地质测量、1:1万磁法及大功率激电中梯测量、偶极测深、对称四极测深、沟系次生晕测量及原生晕测量后,圈定目标矿区约3km^2。综合解译后确定:陡岩电磁性体为顶部埋深250m~270m,厚130m,走向长650m,倾向延深约800m的多金属硫化物地质体。经三个钻孔施工验证,均已见到厚大铜铁矿体,实现隐伏矿床找矿的重大突破。  相似文献   
24.
The April 3, 1998 Mw = 5.1 Gualdo Tadino earthquake (central Italy) was the last significant event in the 6-month-long Umbria–Marche seismic crisis. This event and its aftershocks occurred in an area where active faulting produces no striking geological and geomorphological effects. In this study, we investigated the ruptured fault using detailed seismological data and a re-processed and re-interpreted seismic reflection profile. Aftershock location and focal mechanisms were used to constrain the geometry and kinematics of the ruptured fault and a comparison was made with the subsurface image provided by the seismic profile. We found that the 1998 Gualdo Tadino earthquake occurred on a WSW-dipping, normal fault, with a length of about 8 km and a relatively gentle dip (30°–40°), confined between 3.5 and 7 km in depth. Kinematics of the mainshock and aftershocks revealed a NE-trending extension, in agreement with the regional stress field active in the Northern Apennines belt. The Mw = 5.1 earthquake originated above the top of the basement and ruptured within the sedimentary cover, which consists of an evaporites–carbonates multilayer. We hypothesised that the active fault does not reach the surface (blind normal fault).  相似文献   
25.
Any waterway with one end closed and the other open is generally called a blind channel. The main flow tends to expand, separate, and cause circulation at the mouth of blind channels. The main flow continuously transfers momentum and sediment into the circulation region through the turbulent mixing region (TMR) between them, thus leading to a large amount of sediment deposition in the blind channels. This paper experimentally investigated the properties of the water flow and sediment diffusion in TMR, demonstrating that both water flow and sediment motion in TMR approximately coincide with a similar structure as in the free mixing layer induced by a jet. The similarity functions of flow velocity and sediment concentration are then assumed, based on observation, and the resulting calculation of these functions is substantially facilitated. For the kind of low velocity flow system of blind channels with a finite width, a simple formula for the sediment deposition rate in blind channels is established by analyzing the gradient of crosswise velocity and sediment concentration in TMR.  相似文献   
26.
北天山地区活动逆断裂-褶皱带构造与潜在震源区估计   总被引:27,自引:7,他引:20       下载免费PDF全文
北天山山前逆断裂-褶皱带是典型的大陆内部活动挤压构造,该地区的地表活动构造、隐伏活动构造及活动背斜都受地下深处近水平滑脱断层控制。对1906年玛纳斯地震(M7.7)的发震构造、地表变形与破裂特征和山前活动逆断裂带上古地震的研究表明,北天山山前隐伏活动深断坡具备大地震发生的构造条件,大致以金钩河为界分为东西两段,相应地构成两个大地震潜在震源(M8)。山前第2条玛纳斯逆断裂-褶皱带和第3条独山子逆断裂-褶皱带中的各个活动背斜,以及西湖隆起等可能是8个中强地震的潜在震源(M6)。  相似文献   
27.
发育在北天山山麓的活动断裂褶皱带属于向前扩展的薄皮构造,且所有的背斜都是断裂扩展褶皱,主滑脱面距地表8~9km深。距今292万年以来,地壳缩短13.5~14.6km,缩短率是4.62~5.0mm/a。自30000年前至今,准噶尔南缘断裂和齐古道断裂褶皱带的活动十分微弱,而独山子和玛纳斯道断裂-褶皱带则是活动褶皱-断裂带。北天山地区普遍发育三级阶地,受活动逆断裂和褶皱的影响,均产生褶曲变形和错断。距今12000~13000年以来,吐谷鲁逆断裂-背斜的垂直滑动速率、抬升速率、缩短速率分别是0.83~0.91、3.46~3.75和1.23~1.33mm/a。1906年的玛纳斯地震发生在一条盲断坡上,但是其同震破裂和褶皱隆升却出现在玛纳斯逆断裂-褶皱带上,震中距玛纳斯逆断裂-褶皱带约40km。揭示出北天山挤压拗陷区的孕震构造是一个由深部盲断坡-滑脱断层-浅层断坡构成的复杂构造系统。通过上述活动构造和古地震研究的结果可以推测,天山北麓未来发生大震(M≥7.0)的位置可能是在呼图壁河至金沟河段和金沟河至奎屯河段的齐古道断裂-褶皱带上,其震级相当于1906年玛纳斯地震。乌鲁木齐挤压坳陷中的活动逆断裂褶皱带上只有发生M≤6.0地震的可能性。  相似文献   
28.
保山金厂河大型铜铁多金属隐伏矿床   总被引:3,自引:1,他引:2  
周荣  陈均  吕永增  董文伟 《云南地质》2008,27(2):189-196
隐伏矿床位于金厂河隆起核部上、下两层矽卡岩化带中,垂向上Pb、Zn—Cu、Cu、Fe—Fe多层楼结构,水平上Fe、Cu—Pb、Zn—Cu分带。属热液交代矽卡岩型铜铁多金属矿床。  相似文献   
29.
从研究划分石膏矿化的成因类型入手,进行热液化学成分来源分析和岩石蚀变分带研究,结合典型矿床实例分析,总结出在碳酸盐岩中出现热液交代型石膏矿化体附近,往往伴生有金属硫化矿体或含硫化矿物丰富的岩石,该规律对寻找硫化物型金属自矿体的意义巨大.  相似文献   
30.
This paper presents a structural and stratigraphic analysis of the foreland-fold-belt of the Eastern Venezuelan Basin and the main conclusions about shale tectonic mechanisms in the area. The deformation of the foreland-fold-belt has been investigated analyzing the growth strata architecture preserved on the structure fold limbs. Three contractional episodes are proposed for the Eastern Venezuelan Basin: 1) Oligocene to middle Miocene, 2) late Miocene to Pliocene and 3) Pleistocene. The first episode produced contractional listric faults inside the shale and long displacement blind thrusts in the underlying Cretaceous units. The second episode produced the deformation of the Cenozoic strata into overlapping east-west-trending, convex northward anticlines that covers more than 200 kilometers in length and 40 kilometers wide, break-through normal faults product of a high sedimentary load that overcomes contraction and the formation of short-displacement blind thrusts in the underlying Cretaceous units. The last episode is related to an oblique compression and the formation of high angle extensional faults with dextral movement and NW-SE strike. The role of the shale tectonics in the evolution implies that shale deforms in two stages: 1) folding and 2) normal faulting of the crest of the anticline (Break through normal faulting). Folding controlled the sediment distribution during most of the Neogene strata, while the normal faulting of the anticlines represent basin potential for hydrocarbon. The best potential hydrocarbon plays in the basin are related to oblique-collision restricted basins and controlled by break-through normal faults and the presence of NW-SE strike faults that connect the HC source with the reservoirs. Results from this research imply that the role of sedimentation is fundamental for the overburden sand distribution and tectonic constrain of the folds.  相似文献   
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