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191.
耿国仓  袁效奇 《甘肃地质》1996,5(2):11-20,T004
钻井资料证实,内蒙巴彦浩特盆地东部保存有较完整的石炭系,其中上石炭统羊虎沟组厚达459.6m。经72块岩样分析鉴定,共发现62属119种孢粉,含6个新种。可概括为上下两个孢粉组合,上组合称Densosporitesbelulus-Crassisporalatigranifer-Lycosporagranulata(简称BLG)组合,下组合称Crasisporalatigranifer-Camptoriletesreticuloformis-Vestisporacostata(简称LRC)组合。地质时限为晚石炭世中期羊虎沟组(维斯法期A—C)。  相似文献   
192.
NEE向阿尔金主断裂带的新构造运动以左旋压扭性活动为特征,仅西端发育张性构造,并可划分出两期变形,新构造运动强度在时间上自上新世晚期开始至第四纪断裂活动强度增大,在空间上自SWW向NEE方向断裂活动强度逐渐减弱;柴达木北缘的新构造运动可划分为两期,其主要构造特征表现为向柴达木盆地逆冲的前进式叠瓦道冲带,柴达木盆地第四纪时的北界相对于第三纪时的北界向南迁移了数十公里;河西走廊盆地的新构造运动主要表现为盆地边缘断裂的逆冲兼走滑,盆地接受新生代沉积、盆地内第三系的轴面南倾的褶皱;NEE向阿尔金主断裂带与其南侧的NWW向断裂带是在统一构造应力场作用下相互协调、同时活动的两组关系紧密的构造带,两者的共同活动构成了断块运动。  相似文献   
193.
含油气盆地地球动力学模式   总被引:34,自引:1,他引:34  
陈发景  汪新文 《地质论评》1996,42(4):304-310
文章讨论了含油气盆地地球动力学模式,其中着重讨论了以下几个问题:(1)沉积盆地地球动力学研究的进展,使得能够提出一种根据盆地所处的板块位置和地球动力学模型进行划分的含油气盆地分类;(2)尽管我们有一些古生代克拉通盆地的地球动力学模式,但其成因机制仍缺乏令人信服的解释;(3)通过大陆内裂谷火山岩化学成分、地温场、构造变形、岩石圈结构以及区域板块构造背景综合分析,我们建立了六种大陆裂谷形成的地球动力学模式;(4)前陆盆地的形成与其周缘造山带密切相关,其地球动力学模式是大陆岩石圈对褶皱冲断带构造负载的挠曲响应;  相似文献   
194.
鄂尔多斯西南缘前陆盆地沉降和沉积过程模拟   总被引:17,自引:8,他引:17  
本文将东祁东逆冲带与鄂尔多斯西南缘晚三叠世前陆盆地相结合,研究了逆冲带内部变形特征,前陆盆地中层序地层格架特征及其反映的盆缘构造性质和幕式逆作作用。  相似文献   
195.
Based on fission track dating of apatite, and measurement of vitrinite reflectance of rock samples from the Longmenshan (Longmen Mountain)area and the West Sichuan foreland basin and computer modelling it is concluded that (l)the Songpan-Garze fold belt has uplifted at least by 3-4 km with an uplift rate of no less than 0.3-0.4 mm/a since 10 Ma B.P.; (2) the Longmenshan thrust nappe belt has uplifted at least by 5-6 km with an uplift rate of more than 0.5- 0.6 mm /a since 10 Ma B.P.; (3) the Longmenshan detachment belt has uplifted by 1 - 2 km at a rate of 0.016-0.032 mm/a since 60 Ma B.P.; (4) the West Sichuan foreland basin has uplifted by 1.7-3 km at a rate of 0.028-0.05 mm/a since 60 Ma B.P.; (5) the uplift rate of the area on the west side of the Beichuan-Yingxiu-Xiaoguanzi fault for the last 10 Ma is 40 times as much as that on its east side; (6) the uplifting of the the Songpan - Garze fold belt and the subsidence of the West Sichuan foreland basin 60 Ma ago exhibit a mirro-image correlation, i.e  相似文献   
196.
鹅公山火山盆地受郯庐断裂系影响,NW断裂构造尤为特色:张扭性,倾向NE,右行下滑,对盆地中3个铀矿床及绝大多数铀矿(化)点具明显控制作用,是铀矿成矿的关键要素。研究NW断裂对在鹅公山火山盆地及其它地区找矿都具有实际意义。  相似文献   
197.
 Acid mine drainage (AMD) occurs when sulfide minerals are exposed to an oxidizing environment. Most of the methods for preventing AMD are either short-term or high cost solutions. Coating with iron phosphate is a new technology for the abatement of AMD. It involves treating the sulfide with a coating solution composed of H2O2, KH2PO4, and sodium acetate as a buffer agent. The H2O2 oxidizes the sulfide surface and produces Fe3+ so that iron phosphate precipitates as a coating on the sulfide surface. Experiments performed under laboratory conditions prove that an iron phosphate coating can be established on pyrrhotite surfaces with optimal concentrations of the coating solution in the range of: 0.2M/0.01M H2O2, 0.2M KH2PO4, and 0.2M sodium acetate NaAc, depending on the experimental scale. Iron phosphate coating may be a long-term solution to the problem of AMD. The method would be easy to implement; the reagent cost, however, is not low enough, although it is lower than the conventional treatment with lime. Received: 30 March 1995 · Accepted: 6 September 1995  相似文献   
198.
对处于临滑状态的豆芽棚滑坡进行综合治理,实施排水、加固、支档和减载等工程。经多种监测结果证明,工程治理效果良好。  相似文献   
199.
Water quality impacts from mining in the Black Hills,South Dakota,USA   总被引:1,自引:0,他引:1  
The focus of this research was to determine if abandoned mines constitute a major environmental hazard in the Black Hills. Many abandoned gold mines in the Black Hills contribute acid and heavy metals to streams. In some areas of sulfide mineralization local impacts are severe, but in most areas the impacts are small because most ore deposits consist of small quartz veins with few sulfides. Pegmatite mines appear to have negligible effects on water due to the insoluble nature of pegmatite minerals. Uranium mines in the southern Black Hills contribute some radioactivity to surface water, but the impact is limited because of the dry climate and lack of runoff in that area.  相似文献   
200.
Thorium- and uranium isotopes were measured in a diagenetic manganese nodule from the Peru basin applying alpha- and thermal ionization mass spectrometry (TIMS). Alpha-counting of 62 samples was carried out with a depth resolution of 0.4 mm to gain a high-resolution230Thexcess profile. In addition, 17 samples were measured with TIMS to obtain precise isotope concentrations and isotope ratios. We got values of 0.06–0.59 ppb (230Th), 0.43–1.40 ppm (232Th), 0.09–0.49 ppb (234U) and 1.66–8.24 ppm (238U). The uranium activity ratio in the uppermost samples (1–6 mm) and in two further sections in the nodule at 12.5±1.0 mm and 27.3–33.5 mm comes close to the present ocean water value of 1.144±0.004. In two other sections of the nodule, this ratio is significantly higher, probably reflecting incorporation of diagenetic uranium. The upper 25 mm section of the Mn nodule shows a relatively smooth exponential decrease in the230Thexcess concentration (TIMS). The slope of the best fit yields a growth rate of 110 mm/Ma up to 24.5 mm depth. The section from 25 to 30.3 mm depth shows constant230Thexcess concentrations probably due to growth rates even faster than those in the top section of the nodule. From 33 to 50 mm depth, the growth rate is approximately 60 mm/Ma. Two layers in the nodule with distinct laminations (11–15 and 28–33 mm depth) probably formed during the transition from isotopic stage 8 to 7 and in stage 5e, respectively. The Mn/Fe ratio shows higher values during interglacials 5 and 7, and lower ones during glacials 4 and 6. A comparison of our data with data from adjacent sediment cores suggests (a) a variable supply of hydrothermal Mn to sediments and Mn nodules of the Peru basin or (b) suboxic conditions at the water sediment interface during periods with lower Mn/Fe ratios.  相似文献   
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