内蒙古阿鲁科尔沁地区晚侏罗世侵入岩年代学、地球化学特征及成矿潜力     

鲁艳明  专少鹏  所承逊  殷敏 《现代地质》2016,30(5):981-993

摘要：阿鲁科尔沁地区位于兴蒙造山带东段,中生代岩浆岩分布广泛。对该地区晚侏罗世侵入岩进行了年代学、岩石地球化学及其成矿潜力研究。阿鲁科尔沁地区晚侏罗世侵入岩主要由石英二长闪长岩、石英二长岩、黑云母花岗闪长岩组成,主岩体黑云母花岗闪长岩的LA ICP MS锆石U Pb加权平均年龄为(14379±084) Ma(MSWD=33),属晚侏罗世,在区域Mo Au Cu成矿峰期内。岩体属准铝质高钾钙碱性-钾玄岩系列,相对富碱,稀土元素总量较低,轻重稀土分馏明显,具有中等Eu负异常,富集强不相容元素Rb、Th、U、LREE,亏损高场强元素P、Ti、Y及HREE,相对亏损Nb和Ta,相对亏损大离子亲石元素Ba,属I型花岗岩。岩体主体来源于壳源基性岩组分的部分熔融,形成于晚侏罗世的后碰撞伸展环境,为有利成矿构造演化阶段。K/Rb和Rb/Sr比值较小,DI值较大,SI值较小,Fe2O3/FeO比值较大,属中等-强演化中等分异程度的氧化型或磁铁矿系列花岗岩,地球化学含矿性参数显示其Cu、Au、Mo金属成矿潜力依次降低,与研究区已发现的矿化特征相一致。  相似文献   

结晶岩地区深地震数据采集关键技术与方法   总被引：1，自引：1，他引：0       下载免费PDF全文

陈明春  刘振东  吕庆田  杨文平  严加永  赵金花 《地球物理学报》2015,58(12):4544-4558

深反射地震是了解深部地质结构的主要手段,获取高品质的数据是给出合理地质解释的基础.在结晶岩地区,由于地层成层性差、非均质性严重,地震散射效应明显,导致地震波场复杂,同时结晶岩为非理想弹性体,不利于地震波能量转换,有效反射能量弱,信噪比低.加之深反射地震的目标层较深且受环境噪声干扰严重,高频信号衰减快,地震资料主频较低.这些因素使得在结晶岩区难以获得高品质的地震资料,为探索提高该类地区深反射地震资料质量的方法和技术,本文依托长江中下游成矿带2009—2014年深反射地震数据采集工作,在精细设计、严格施工的基础上,从激发和接收入手,开展了"轴向不耦合激发"、"宽频接收"和"宽线观测"等技术方法试验研究.结果表明,这些方法技术措施提高了下传弹性波能量,展宽了接收地震信号的频带,提高了覆盖次数和信噪比,有效改善了地震原始资料的品质和成像效果.研究结果对今后结晶岩地区深地震反射数据采集工作具有重要的实用价值和参考意义.  相似文献   

ESR/U-series dating of faunal remains from the paleoanthropological site of Biache-Saint-Vaast (Pas-de-Calais,France)     

《Quaternary Geochronology》2015

Discovered accidently during factory building construction works, the Middle Palaeolithic site of Biache-Saint-Vaast (Pas-de-Calais, France) was excavated from 1976 to 1982 by a team of Lille University directed by Alain Tuffreau. An abundant archaeological and paleontological material, including two human skulls, was there recovered from fossil alluvial deposits of the Scarpe River. In order to determine the ages of these remains, the ESR/U-series method was applied on bone and teeth. As the U-series data obtained of the main part of the analyzed tissues do not allow the use of the classical US-ESR model, the recently proposed AU-ESR model, taking into account if necessary U-leaching from some of the tissues, was used to calculate combined ESR/U-series ages for these samples. The obtained ages suggest a MIS7 attribution to the faunal remains and permit an age of ca 240 ka to be assigned for the human remains and associated archaeological material, in accordance with the stratigraphic data and the large mammal associations.  相似文献   

Optical dating of flowstone and silty carbonate-rich sediments from Panxian Dadong Cave,Guizhou, southwestern China     

《Quaternary Geochronology》2015

Panxian Dadong Cave located in the western Guizhou is a very important Paleolithic site in China. At this site bone and stone artifacts, human teeth and mammalian fossils (known as Ailuropoda-Stegodon fauna) were found, and the site was previously dated to 120–300 ka using ESR/uranium-series methods. In this study, we successfully extracted fine quartz grains from flowstone and silty carbonate-rich sediments in the excavated area. The quartz extracts displayed excellent luminescence properties, and satisfied the SAR (single-aliquot regenerative dose method) acceptance criteria. The sensitivity-corrected OSL signals are not saturated at a dose up to about 1400 Gy. The cultural unit was OSL dated to 190–300 ka, corresponding to MISs 7–8. The flowstone deposits overlying the cultural unit were determined to be 13–190 ka and the silty carbonate-rich sediments underlying the cultural unit to be 300–360 ka. The optical ages are in general agreement with the coupled ESR/U-series and U-series ages.  相似文献   

青海木里聚乎更天然气水合物潜在区中侏罗世岩相古地理特征     

邵龙义  杨致宇  李永红  商晓旭  王伟超  吕景高  文怀军 《现代地质》2015,29(5):1061-1072

青海聚乎更矿区不仅赋存丰富的煤炭资源,同时也是全球陆域中纬度高海拔地区天然气水合物的首要发现地,同时也是我国非常规天然气(煤层气和页岩气)勘探开发的潜在热点地区,且天然气水合物勘探的层位主要为中侏罗世含煤岩系。通过对青海聚乎更矿区中侏罗世含煤地层野外露头、钻孔岩心、测井等资料整理分析的基础上,对研究区内中侏罗世含煤岩系沉积时期的沉积环境及古地理进行了分析。以定量和定性分析相结合的方法对研究区岩相古地理进行重建。以钻孔沉积相分析为基础,结合单因素分析多因素综合作图法及研究区目的层段沉积相断面图分析,最终恢复各段沉积期的岩相古地理格局。木里组下段岩性主要为细砾岩、含砾粗砂岩及粗砂岩等粗粒岩性,分析认为木里组下段主要发育辫状河沉积;木里组上段随着水体的不断加深,发育形成 了研究区主采的下1、下2煤层,该段主要以三角洲沉积为主,同时研究区西南区域发育滨浅湖沉积;江仓组上段沉积时期,水体进一步加深,成煤环境逐渐变差,发育形成多套薄煤层,以三角洲沉积为主,西南区域的滨浅湖沉积范围进一步扩大;江仓组上段是发现水合物的主要层段,其岩性主要以油页岩、暗色泥岩等为主,含有典型的湖泊沉积的瓣鳃类化石,为湖泊沉积。总体上,聚乎更矿区在中侏罗世经历了辫状河、三角洲平原、三角洲前缘、滨浅湖、半深湖-深湖的持续变深的演化过程。  相似文献   

雪峰山西侧地区中上寒武统——层序地层学特征及层序格架     

赵灿  李旭兵  郇金来  陈孝红  刘安  危凯  张华 《吉林大学学报(地球科学版)》2015,45(2):518-532

综合利用沉积学、岩石矿物学、碳同位素地球化学等分析手段,对研究区中-上寒武统层序地层学特征进行了分析。结果表明:中-上寒武统可以划归为1个二级层序和5个三级层序,在二级层序时限范围内,浅水相区经历了由局限台地潮坪→开阔台地→局限台地潮坪的沉积演化,斜坡过渡带则经历了由台地边缘→前缘缓斜坡→台地边缘的演化,研究区东南部的深水相区则由深陆棚→盆地→浅水陆棚组成。三级层序海侵体系域中沉积的颗粒白云岩、叠层石礁以及晚期高水位体系域中形成的溶孔白云岩、岩溶角砾白云岩的层位具有重要的油气勘探潜力,是值得关注和研究的领域。  相似文献   

大兴安岭扎兰屯地区格根敖包组碎屑锆石U-Pb年代学、地球化学特征及其地质意义   总被引：2，自引：0，他引：2  

张渝金  吴新伟  江斌  郭威  杨雅军  刘世伟  崔天日  李伟  李林川  司秋亮  张超 《吉林大学学报(地球科学版)》2015,45(2):404-416

格根敖包组广泛分布在大兴安岭中段扎兰屯地区,为一套偏中性的火山岩及碎屑岩组合,主要为安山岩、安山质火山碎屑岩、英安岩及细-粉砂岩,夹薄层泥岩。笔者对格根敖包组中细碎屑岩进行了锆石LA-ICP-MS U-Pb年代学及古生物地层学研究,结果表明:格根敖包组细碎屑岩形成于晚石炭世至早二叠世,锆石U-Pb年龄集中于348.9,385.8,428.0和507.3 Ma 4个峰值;粉砂岩中存在Artisia sp., Eusigillaris sp.等化石。格根敖包组碎屑岩主要以细粒杂砂岩和细粒长石(岩屑)砂岩为主,主量元素平均质量分数w(SiO₂)=69.04%,w(Al₂O₃)=14.76%,w(MgO)=1.05%,w(CaO)=0.66%,w(Na₂O)=2.34%,w(K₂O)=2.65%;镁铝比值M为3.05~9.98,平均值7.18;稀土元素总量∑REE平均184.46×10^-6((124.06~261.96)×10^-6),δEu平均值0.71,δCe平均值0.99,LREE富集,HREE亏损。上述结果表明,格根敖包组地层形成于大陆岛弧-活动陆缘附近,古地理显示为温暖潮湿气候下的海陆交互相沉积环境。  相似文献   

Numerical study of shoreline changes by emergency beach nourishment project at the Middle Beach of Beidaihe, China   总被引：1，自引：1，他引：0  

ZHANG Yu  HE Lulu  KUANG Cuiping  PAN Yi  GU Jie  YANG Yanxiong  ZHANG Jiabo 《海洋学报(英文版)》2012,31(1):125-133

Beach nourishment is a common coastal management strategy used to protect beach from erosion along the sandy coastlines. This method has been successfully applied to an emergency project at the West Beach of Beidaihe in the summer of 2008 and the full West Beach nourishment project in 2009-2010, which is the direct base of this study. Some basic information about the emergency engineering area at the Middle Beach is firstly described. The shoreline change of this area, including the analysis of beach width in five monitoring profiles in the bathing places of Middle Beach, is then discussed. After that a numerical model based on one-line theory is established and the numerical results agree well with the measured shorelines, which indicates that the model is appropriate and is qualified to predict the shoreline change of the Middle Beach. With the same model and parameters, long-term performance of the project is predicted, and the result shows that without follow-up nourishment and project, the bathing places can remain suitable for bathing for about 10 a. It is suggested to nourish the beach in time and carry out the beach nourishment project for the full Middle Beach in Beidaihe.  相似文献   

南水北调中线典型承压水地层渠段渗流场数值分析     

崔皓东  张家发  张伟  王金龙 《岩土力学》2010,31(Z2):447-451

南水北调中线工程中,渗流问题是影响渠道衬砌及渠坡稳定的关键因素之一,在具有承压水地层的深挖方渠段尤其如此。为更全面分析该类渠段渗流场分布特征及渗控措施合理性,采用渗流自由面、密集排水孔三维有限元精细模拟技术,针对典型深挖方渠段建立渗流模型,模拟渠道渗流场分布,分析渗控措施的效果。结果表明,在具有承压水地层渠段布置排水垫层,并结合逆止阀以及渠坡排水孔等综合措施,能有效降低渠底衬砌板下扬压力,为工程安全运行提供有力保障。  相似文献   

Synoptic measurements of episodic offshore flow events in the central mid-Atlantic Bight     

Brian Dzwonkowski  B.L. Lipphardt Jr.  Josh T. Kohut  Xiao-Hai Yan  Richard W. Garvine 《Continental Shelf Research》2010

Sub-inertial across-shelf flows over the central mid-Atlantic Bight were examined using long-range CODAR SeaSonde type HF-radar surface velocities for the period August 2002 through February 2004. Across-shelf flow in this region was found to be episodic, with offshore flow occurring six times more often than onshore flow. Several recurring spatial patterns in offshore flow are identified, and two of these patterns emerge as statistically significant using empirical orthogonal functions. The most common type of offshore flow was a shelf-wide flow with events occurring throughout the year. The most energetic and well-defined shelf-wide flow events occurred during October through April, when the water column was less stratified. Other offshore flow patterns were more localized, with a flow at the bend or ‘point’ in the New Jersey coast being most common and most energetic. The offshore flow events identified here are capable of driving significant offshore transport, with more than one-third of offshore flow episodes having potential transport distances of greater than 14 km. In addition, clusters of multiple offshore flow events are shown to be capable of transporting near-surface material across much of the continental shelf.  相似文献