山东省海岸带城市建设面临的地质环境因素浅析

通过对山东省海岸带城市地质环境条件的调查与研究,归纳总结出山东省海岸带城市建设新近面临的影响城市发展的地质环境因素,即城市应急水源地建设、城市地下空间的开发、城市边缘区生态规划建设、湿地资源开发与保护,均是制约城市发展的主要因素,并提出了保护措施和建议,供有关部门在城市规划建设过程中参考。     

山东省招远市后仓地区金矿成矿地质特征

山东省招远市后仓地区位于胶东半岛的北部,其大地构造处于华北地台胶东台隆之胶北隆起区,区内构造活动和岩浆活动强烈,岩石蚀变及矿化现象比较普遍,已经发现2条矿体,具有较好的成矿条件和找矿前景。     

山东阳谷茌平煤田阿城井田山西组煤岩层对比研究

通过对山西组沉积特征及聚煤变化规律的研究,采用煤岩层组合特征、标志层、层间距、测井曲线形态和地震物性特征等方法,对井田内山西组的煤、岩层进行综合对比。确定了山西组主采煤层的赋存层位、形态及区内的构造方案,对周边地区找煤工作具有指导作用。     

山东省东平县大洪顶山地区岩溶洞穴景观资源评价

东平县大洪顶山岩溶地貌类型属岩溶山地地貌单元,山坡顶部及陡峭坡段岩石裸露,岩溶裂隙发育,岩体切割破碎,边坡陡立。区内岩溶洞穴发育,岩溶景观资源众多。目前已发现的溶洞有6处,大洪顶山南坡3处,北坡3处,溶洞口出露位置呈NWW向展布,北部九仙洞已探测长度1862 m,南部神仙洞已探测长度2052．50 m,溶洞内岩溶景观发育不均匀,发育有石笋、石钟乳、石幔、石帽、边石等。区内岩溶洞穴发育规模宏大,景观资源丰富,属鲁西地区发育规模最大的溶洞,在北方地区具代表性、典型性、稀有性,属我国北方地区不可多得的地质自然遗产,具有良好的开发前景及旅游价值。     

万福矿井充水水源分析及矿井涌水量预计

通过对井田水文地质特征及矿井充水因素的分析,认为矿井的主要充水水源为3煤层顶底板砂岩裂隙含水层及三灰岩溶裂隙含水层。采用“大井法”对矿井涌水量进行了预算,确定矿井的正常涌水量为279 m3/h,预算结果为矿井的设计提供了科学依据。     

甘肃省泥石流发育特征、成因分析及其危害

甘肃省是我国泥石流地质灾害最为严重的4大省份之一。据统计,全省发育有泥石流沟6 260条,这些泥石流沟大部分集中在东部地区,河西地区较少。泥石流强烈发育的陇南、甘南山区,地势高差多在1 000m以上,山坡坡度≥30°。区内地质构造复杂,地震活动频繁,广泛分布黄土、泥岩、千枚岩、页岩等软弱易滑岩土体,为泥石流发育提供了必要的地形条件和岩土条件,降雨和地震及人类活动是诱发因素。长期以来,频繁发生的泥石流地质灾害已给甘肃人民的生命财产和工农业生产建设带来了严重威胁和危害,造成约3 715人死亡,直接经济损失几十亿。其中,2010年8月8日,舟曲发生的特大泥石流地质灾害震惊世界,泥石流地质灾害已严重困扰和和制约着甘肃省的国民经济发展和广大人民群众的正常生活。因此,应通过科学规划人类活动,采取必要的工程措施制约泥石流地质灾害的发生,减轻泥石流地质灾害造成的损失。     

Evolution of neotectonic activity of East Anatolian Fault System (EAFS) in Bingöl pull-apart basin,based on fractal dimension and morphometric indices

This study is an attempt of a semi-automatic geomorphological GIS analysis based on morphometric indices. In the study, 10-m-resolution Digital Elevation Models (DEMs) are used to assess the neotectonic signals regarding the recent topographic developments and to attach additional significance to active tectonics in the Bingöl basin area. The methodology incorporates the determination of the structural similarities of the faults in the basins using fractal concepts and the application of four morphometric indices (Stream Power Index (SP), Multi-resolution Index of Valley Bottom Flatness (MRVBF), Terrain Ruggedness Index (TRI) and Valley Width-to-Height Ratio (Vf)). In order to detect the deviation from spatial randomness of the applied indices, the weighted correlation coefficient Moran’s I is used and the results are interpreted at a confidence interval of 99%. The spatial distribution of integrated index values is evaluated with the tectonically active fault zones in order to determine the probable activity and the structural deformation in the basin.The applied methodology reveals that the fractal analysis of the fault lines and the spatial analysis of the morphometric indices proved to be effective tools in analyzing the tectonic influence of the fault system on the basin area. Within the basin area, a relatively lesser degree of tectonic activity is observed, in contrast with the high tectonic activity outside the basin.     

The Deccan Trap – Cretaceous–Paleogene boundary connection; new 40Ar/39Ar ages and critical assessment of existing argon data pertinent to this hypothesis

The Cretaceous–Paleogene boundary (KPgB) was dated by the ⁴⁰Ar/³⁹Ar method herein from the western interior of North America at 65.48 ± 0.12 Ma (1σ), in good agreement with other recent published estimates. For the Deccan Traps, India, new argon ages as well as others available in the literature, are assessed for reliability based on (a) statistical reliability of plateau/isochron sections and (b) freshness of material dated utilizing the alteration index method. From tholeiitic lavas from the Composite Western Ghats Section (CWGS), only six ages are found to be reliable estimates of the time of crystallization. These ages along with the magnetic polarity of the lavas agree with the geomagnetic polarity time scale (GPTS) at ∼67–64 Ma. Alkaline rocks from the Anjar area of Kutch, provide three reliable ages that suggest a hiatus in lava extrusion around KPgB. For the Rajahmundry basalts, the upper flow’s age defines its formation during chron 29n; a single age from the lower reversed polarity flow appears somewhat dichotomous when plotted against the GPTS. The reliable lava ages indicate the most voluminous (reversed polarity) sections of the CWGS were extruded at a time statistically indistinguishable from that of the KPgB. The Deccan Trap – KPgB faunal extinction hypothesis remains plausible, but must compete with the latest report, favoring a very close temporal connection (∼0.03 m.y.) between the Chixculub (Impact) Crater and the KPgB.     

Geochronology and fluid inclusion study of the Yinjiagou porphyry–skarn Mo–Cu–pyrite deposit in the East Qinling orogenic belt,China

The Yinjiagou Mo–Cu–pyrite deposit of Henan Province is located in the Huaxiong block on the southern margin of the North China craton. It differs from other Mo deposits in the East Qingling area because of its large pyrite resource and complex associated elements. The deposit’s mineralization process can be divided into skarn, sulfide, and supergene episodes with five stages, marking formation of magnetite in the skarn episode, quartz–molybdenite, quartz–calcite–pyrite–chalcopyrite–bornite–sphalerite, and calcite–galena–sphalerite in the sulfide episode, and chalcedony–limonite in the supergene episode. Re–Os and ⁴⁰Ar–³⁹Ar dating indicates that both the skarn-type and porphyry-type orebodies of the Yinjiagou deposit formed approximately 143 Ma ago during the Early Cretaceous. Four types of fluid inclusions (FIs) have been distinguished in quartz phenocryst, various quartz veins, and calcite vein. Based on petrographic observations and microthermometric criteria the FIs include liquid-rich, gas-rich, H₂O–CO₂, and daughter mineral-bearing inclusions. The homogenization temperature of FIs in quartz phenocrysts of K-feldspar granite porphyry ranges from 341 °C to >550 °C, and the salinity is 0.4–44.0 wt% NaCl eqv. The homogenization temperature of FIs in quartz–molybdenite veins is 382–416 °C, and the salinity is 3.6–40.8 wt% NaCl eqv. The homogenization temperature of FIs in quartz–calcite–pyrite–chalcopyrite–bornite–sphalerite ranges from 318 °C to 436 °C, and the salinity is 5.6–42.4 wt% NaCl eqv. The homogenization temperature of FIs in quartz–molybdenite stockworks is in a range of 321–411 °C, and the salinity is 6.3–16.4 wt% NaCl eqv. The homogenization temperature of FIs in quartz–sericite–pyrite is in a range of 326–419 °C, and the salinity is 4.7–49.4 wt% NaCl eqv. The ore-forming fluids of the Yinjiagou deposit are mainly high-temperature, high-salinity fluids, generally with affinities to an H₂O–NaCl–KCl ± CO₂ system. The δ¹⁸O_H2O values of ore-forming hydrothermal fluids are 4.0–8.6‰, and the δD_V-SMOW values are between −64‰ and −52‰, indicating that the ore-forming fluids were primarily magmatic. The δ³⁴S_V-CDT values of sulfides range between −0.2‰ and 6.3‰ with a mean of 1.6‰, sharing similar features with deeply sourced sulfur, implying that the sulfur mainly came from the lower crust composed of poorly differentiated igneous materials, but part of the heavy sulfur came from the Guandaokou Group dolostone. The ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb, and ²⁰⁸Pb/²⁰⁴Pb values of sulfides are in the range of 17.331–18.043, 15.444–15.575, and 37.783–38.236, respectively, which is generally consistent with the Pb isotopic signature of the Yinjiagou intrusion, suggesting that the Pb chiefly originated from the felsic–intermediate intrusive rocks in the mine area, with a small amount of lead from strata. The Yinjiagou deposit is a porphyry–skarn deposit formed during the Mesozoic transition of a tectonic regime that is EW-trending to NNE-trending, and the multiepisode boiling of ore-forming fluids was the primary mechanism for mineral deposition.     

辽宁省建平县高杖子金矿地质特征及成因探讨

高杖子金矿成因类型为中温热液蚀变岩型,新太古代叶柏寿片麻杂岩为其矿源层,燕山期发育的北东、北北东及北西向断裂是控制金矿的主要构造.在区域岩浆热动力作用下,金元素活化转移,金在富含挥发份及碱质的流体中迁移,在适当的压力、温度和介质条件下,在有利的构造部位富集成矿.