冀北赤城二堡子片麻状角闪二长岩的锆石SIMS U-Pb年龄及其地质意义     

商光锐  倪志耀  刘瑶  张虹  王阳阳 《矿物岩石》2019,39(3):32-41

运用岩相学研究理论和元素地球化学研究理论,针对冀北赤城二堡子片麻状角闪二长岩,进行岩相学(4件样品)和地球化学分析(4件样品),结果表明:角闪二长岩的矿物成分为斜长石(30%~35%)、碱性长石(25%~30%)、角闪石(15%~20%)、石英(10%~15%)和黑云母(5%~10%)等。岩石中w(SiO2)介于60.16%~62.16%之间,w(K2O+Na2O)为8.56%~8.82%,稀土总量较高(ΣREE为246.30×10-6~317.76×10-6),(La/Yb)N值为28.18~42.79,具有轻稀土富集、重稀土亏损的分配模式,Eu异常(Eu/Eu*值为0.90~1.03)及Ce异常(Ce/Ce*值为0.91~0.98)均不明显,富集大离子亲石元素(如Ba,Rb,Sr和Th等)及轻稀土元素(如La,Ce和Nd等),亏损高场强元素(如Nb,Ta,Zr和Hf等)。角闪二长岩的锆石SIMS U-Pb年龄为243.1Ma±1.8 Ma,锆石的Th/U比值为0.709~1.258,表明其形成于三叠纪,应该是中生代印支期岩浆作用的产物,这是赤城地区确定的第二个印支期中酸性侵入岩体,其形成可能与赤城-崇礼断裂带在印支期重新活动有关。赤城印支期角闪二长岩体的确定表明赤城、崇礼地区存在印支期(~239Ma^243Ma)岩浆-变质-构造热事件,这对于冀北大地构造演化特征的确定具有重要的指示意义。  相似文献   

基于冻融交界面直剪试验的冻土斜坡失稳过程研究   总被引：1，自引：0，他引：1  

高樯  温智  王大雁  牛富俊  谢艳丽  苟廷韬 《岩土力学》2018,39(8):2814-2822

为了探讨多年冻土区自然斜坡失稳机制,开展了不同含水率黏土、粉土、砂土的土-冰交界面直接剪切试验和相应融土的直接剪切试验。结果表明,砂土和砂土-冰冻融交界面剪切应力-变形特性主要表现为弹性变形,且剪应力存在明显峰值;粉土、黏土及相应的冻融交界面在很小的变形范围内表现为塑性变形,且剪应力无峰值。水分对砂土活动层抗剪强度影响较弱,表现为水分增高,内摩擦角小幅降低。水分对粉黏土活动层抗剪强度影响剧烈,表现为水分增高,粉黏土黏聚力急剧减小。研究发现,冻土区斜坡失稳更易发生于细颗粒粉黏土中。相对于粉土,粉土-冰冻融交界面抵抗剪切变形的能力更强,粉土斜坡潜在滑动面更易发育在冻融交界面上层附近;相对于黏土,黏土-冰冻融交界面抵抗剪切变形的能力更弱,黏土斜坡更易在冻融交界面处发生滑动。同时,细粒土斜坡极易在达到最大融化深度前提前失稳,斜坡坡度越高,失稳时间越提前。融化期活动层水分增多导致潜在滑动面黏聚力降低是细粒土冻土斜坡失稳的最主要原因,孔隙水压对冻土斜坡具有一定影响,在稳定性评价时要考虑活动层水位的影响。  相似文献   

基于MatDEM的砂土侧限压缩试验离散元模拟研究   总被引：2，自引：2，他引：0  

秦岩  刘春  张晓宇  邓尚 《地质力学学报》2018,24(5):676-681

离散元法基于非连续介质力学理论,尤其适用于砂土等离散介质体的数值模拟研究。利用岩土体离散元模拟软件MatDEM的二次开发功能,研发了砂土侧限压缩试验三维离散元模拟器。对三个不同级配砂土试样进行了侧限压缩试验,并且进行了与之相对应的数值模拟,通过分析对比试验结果与数值模拟结果验证了所开发模拟器的有效性。模拟结果表明:离散元法可以很好地反应砂土压缩过程中的配位数变化;每个模拟样品中,粒径较小的单元受到较大的平均压力,导致平均位移较大;数值计算结果的主要误差是由离散元颗粒自身的泊松比引起的。研究突破了常规土力学研究方法的局限性,为今后岩土工程离散元模拟研究提供了参考。   相似文献   

层状复合氢氧化物对硫酸钠的阴离子交换作用          下载免费PDF全文

苟国敬  许红平  鲍凤娟 《盐湖研究》2008,16(4)

以0.004~0.80 mol.L-1的Na2SO4溶液为交换介质,测定了层状复合氢氧化物(LDH)[Mg4.7Al(OH)11.4]Cl0.96(OH)0.04.7.9H2O在超声条件下的离子交换容量和交换平衡常数。结果显示层间Cl-离子的最大交换容量为1.497 mmol.g-1,OH-离子的最大交换容量为0.026 8 mmol.g-1,交换平衡常数pK值为3.65;固相的XRD、IR及BET-N2表征显示交换反应后SO42-的Td对称性降低,LDH的晶胞参数c和通道高度h增大,结晶度下降,微晶的层间吸附活性降低,微孔吸附容量减小。  相似文献   

Variability of suspended particulate matter in the Bohai Sea from the geostationary Ocean Color Imager (GOCI)   总被引：2，自引：0，他引：2  

Kevin Ruddick  Quinten Vanhellemont  Jing Yan  Griet Neukermans  Guomei Wei  Shaoling Shang 《Ocean Science Journal》2012,47(3):331-345

This study assesses the performance of the Geostationary Ocean Imager (GOCI) for mapping of suspended particulate matter in the Bohai Sea, a turbid water region. GOCI imagery for remote sensing reflectance and Total Suspended Solids (TSS) is analysed in detail for two days in June 2011 (8 images per day). Both instantaneous and daily composite maps are considered and a comparison is made with corresponding reflectance and TSS products from MODIS-AQUA. Results show TSS distributions corresponding to previous studies of the region. The advantage of the higher acquisition frequency (8 images/day instead of 1) offered by GOCI is clearly demonstrated in the daily composite which is more complete during this period of scattered but moving clouds. Consideration of temporal variation over the day indicates low natural variability but some artificial variability from processing errors ?? this analysis provides a first indication of how the higher frequency of data from geostationary ocean colour could lead to improved data quality control via temporal coherency outlier detection. While there is room for improvement on the GOCI calibration, atmospheric correction and retrieval algorithms, the current study suggests that the GOCI data can already be used now to study qualitatively sediment dynamics except in the extremely turbid waters which are masked out of the current dataset. In a wider context, it is considered that the technical challenges of geostationary ocean colour have been met by the GOCI concept, and, notwithstanding potential improvements on the concept and data processing methods, it is recommended that this mission serve as a model for future geostationary ocean colour sensors over Europe/Africa and the Americas.  相似文献   

中国海域区古近纪含煤盆地与煤系分布研究   总被引：1，自引：0，他引：1  

李增学  张功成  李莹  刘海燕  吕大炜  沈怀磊  尚鲁宁 《地学前缘》2012,19(4):314-326

新近纪和古近纪是全球重要的聚煤期。中国古近纪聚煤盆地分布在东部沿海省区,是全球性环太平洋聚煤带的组成部分。中国海域区含煤沉积盆地虽然也属于断陷盆地和坳陷盆地类型,且成群出现,但总体构造背景有利于含煤沉积的持续发展,盆地群连续性好,含煤沉积厚度大,如琼东南盆地、东海海域西湖凹陷,含煤沉积厚度达1 km以上,这是陆上区古近纪含煤盆地所不能相比的。研究表明,海域区的聚煤盆地内大多由若干凹陷组成,为聚煤凹陷,可分为两大类,即半地堑凹陷和地堑凹陷。根据成煤盆地的水体深浅又可分为深水半地堑凹陷和浅水半地堑凹陷,地堑凹陷均为深水凹陷。盆地内表现为明显的两个聚煤带：缓坡聚煤带和陡坡聚煤带,缓坡聚煤带占绝对优势。在潮坪体系的潮上带和潮间带沼泽,利于聚煤作用的广泛发生。泥炭的堆积可能存在两种形式：原地堆积和异地堆积。由于盆地构造的频繁活动异地堆积可能是海域区聚煤盆地成煤作用的重要形式。海域区巨厚的含煤沉积为海域区煤成气成藏提供了丰厚的物质基础。又由于含煤地层埋深大,煤的变质作用程度相对较高,成为良好的烃源岩。  相似文献   

蔚县盆地中更新世哺乳动物化石新发现          下载免费PDF全文

贠杰  赵力颖  岳峰  鲁艳明  李广栋  高尚  何立  周明兴  张亚光  张运强 《中国地质》2022,49(1):348-349

1 研究目的(Objective) 蔚县盆地为典型的冀西北山间盆地,与阳原盆地仅一山之隔,二者共同组成了广义的"泥河湾盆地",盆地内广泛出露中更新统郝家台组(Qp2h)河-湖相沉积物.相比阳原盆地,蔚县盆地古生物化石研究程度较低.20世纪80年代,盆地北部(大南沟一带)出土具有上新世—早更新世面貌的小型哺乳动物化石,近...  相似文献   

盆地深部穹隆构造发育特征、成因机制及石油地质意义——以塔里木盆地顺北地区为例   总被引：1，自引：0，他引：1  

高天  邓尚  李海英  刘雨晴  黄诚  艾合买提江·阿不都热和曼 《地质论评》2022,68(1):217-232

塔里木盆地顺北地区奥陶系碳酸盐岩中广泛发育穹隆构造.为研究盆地深部穹隆构造的发育特征、成因机制及石油地质意义,基于顺北地区高精度三维地震资料,对穹隆构造开展几何学定量解析,确定其空间分布规律及内部结构样式;结合区域构造背景及盆内构造发育特征,明确其成因机制;在此基础上,结合生产动态数据探讨穹隆构造的控储—控藏作用.研究...  相似文献   

Modern pollen rain in the Lake Qinghai basin,China     

SHANG Xue    LI XiaoQiang  AN ZhiSheng  JI Ming  & ZHANG HongBin  State Key Lab of Loess & Quaternary Geology  Institute of Earth Environment  Chinese Academy of Sciences  Xi’an  China  Graduate University of Chinese Academy of Sciences  Beijing 《中国科学D辑(英文版)》2009,52(10):1510-1519

Lake Qinghai is the largest inland brackish lake in China and lies within the NE Tibetan Plateau. Our study shows that pollen assemblages in each vegetation belt are significantly correlated with the vegetation types of this area. Among the herbaceous and shrubby pollen assemblages, Artemisia is over-represented, while Poaceae, Cyperaceae and Polygonaceae are under-represented. Artemisia/ Chenopodiaceae (A/C) ratios with the regional vegetation characteristic can be used as a proper index to reconstruct the...  相似文献   

Temperature reconstruction from tree-ring maximum latewood density of Qinghai spruce in middle Hexi Corridor, China     

Feng Chen  Yu-jiang Yuan  Wen-shou Wei  Shu-long Yu  Zi-ang Fan  Rui-bo Zhang  Tong-wen Zhang  Qin Li  Hua-ming Shang 《Theoretical and Applied Climatology》2012,107(3-4):633-643

Seven different tree-ring parameters (tree-ring width, earlywood width, latewood width, maximum density, minimum density, mean earlywood density, and mean latewood density) were obtained from Qinghai spruce (Picea crassifolia) at one chronology site in the Hexi Corridor, China. The chronologies were analyzed individually and then compared with each other. Growth–climate response analyses showed that the tree-ring width and maximum latewood density (MXD) are mainly influenced by warm season temperature variability. Based on the relationships derived from the climate response analysis, the MXD chronology was used to reconstruct the May–August maximum temperature for the period 1775–2008 A.D., and it explained the 38.1% of the total temperature variance. It shows cooling in the late 1700s to early 1800s and warming in the twentieth century. Spatial climate correlation analyses with gridded land surface data revealed that our warm season temperature reconstruction contains a strong large-scale temperature signal for north China. Comparison with regional and Northern Hemisphere reconstructions revealed similar low-frequency change to longer-term variability. Several cold years coincide with major volcanic eruptions.  相似文献