LA-ICP-MS测定锡石U-Pb同位素年龄时两种普通铅扣除方法的原理及适用性比较   总被引：1，自引：0，他引：1  

郝爽  李惠民  李国占  耿建珍  周红英  肖志斌  崔玉荣  涂家润 《地质通报》2016,35(4):622-632

根据近年来激光烧蚀电感耦合等离子体质谱仪锡石微区原位U-Pb同位素定年的实验结果,结合相关资料,对实验过程中普通铅扣除的2种主要方法,即谐和图法和等时线法的原理、效果、优点和局限性进行了深入的比较。研究成果表明,2种主要方法各有不同的优点及局限性。在实际工作中,要想获得比较准确的测试结果,需要根据具体矿物样品的年龄范围、总的U和Pb含量、普通铅相对含量、测年精度要求等因素,灵活地选择普通铅扣除的方法。  相似文献   

Coupled discrete element–finite difference method for analyzing subsidence control in fully mechanized solid backfilling mining     

Xiaojun Zhu  Guangli Guo  Qi Fang 《Environmental Earth Sciences》2016,75(8):683

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Rotation Center and Horizontal Bearing Capacity of the Bucket Foundation in Soft Ground     

Xiaowei Tang  Xiwen Zhang  Qi Shao  Zhenqing Li 《Marine Georesources & Geotechnology》2016,34(6):594-601

In the last 20 years, the bucket foundation has been developed as a new type of offshore platform structure. Because of its short period of application to engineering practices, the theoretical decision on the rotation center and horizontal bearing capacity of the bucket foundation has yet to be agreed. A limit analysis method is used to determine the updated rotation center position and horizontal bearing capacity to evaluate the failure mechanisms of the bucket foundations. The results are compared with numerical simulation and experiments, and also with other theoretical methods. The proposed method can satisfactorily consider the engineering conditions and the result is accurate in determining the rotation center and horizontal bearing capacity.  相似文献   

Influencing factors of seed long-distance dispersal on a fragmented forest landscape on Changbai Mountains,China     

Fuqiang Zhao  Lin Qi  Lei Fang  Jian Yang 《中国地理科学(英文版)》2016,26(1):68-77

Seed long-distance dispersal(LDD) events are typically rare, but are important in the population processes that determine large-scale forest changes and the persistence of species in fragmented landscapes. However, previous studies focused on species dispersed via animal-mediated LDD, and ignored those dispersed by wind. The aim of this study was to assess the effects of canopy openness, edge, seed source, and patch tree density on the LDD of seeds by wind in forest. We collected birch seeds, a typical wind-dispersed species, throughout a larch plantation. We then assessed the relationship between birch LDD and each factor that may influence LDD of seeds by wind including distance to edge, canopy openness size, distance to mature forest, and the tree density of the larch plantation. We used univariate linear regression analysis to assess the influence of those factors on birch LDD, and partial correlations to calculate the contribution of each factor to LDD. The results showed that both canopy openness and edge had significant influences on birch LDD. Specifically, a negative relationship was observed between distance to edge and birch LDD, whereas there was a positive correlation between canopy openness size and LDD. In contrast, the distance to the mature forest was not correlated with birch LDD. Our results suggest that patch tree density could potently affect the probability of LDD by wind vectors, which provides novel and revealing insights regarding the effect of fragmentation on wind dynamics. The data also provide compelling evidence for the previously undocumented effect of habitat fragmentation on wind-dispersed organisms. As such, these observations will facilitate reasonable conservation planning, which requires a detailed understanding of the mechanisms by which patch properties hamper the delivery of seeds of wind-dispersed plants to fragmented areas.  相似文献   

Advance in Matrix Effect Study of LA‐MC‐ICPMS U‐Pb Dating on U‐Bearing Oxide Minerals     

CUI Yurong  TU Jiarun  GENG Jianzhen  YE Lijuan  ZHOU Hongying  LI Huimin 《《地质学报》英文版》2018,92(4):1680-1681

正Objective With the development of analytic technologies,in-situ dating on U-bearing oxide minerals(e.g.,cassiterite,rutile and baddeleyite)has been widely used in geological chronological researches and has attracted remarkable attention to explore evolution of the earth and obtain age information of various geological processes.Matrix effect  相似文献   

Identification and determination of the boundary between the Cathaysian and Yangtze blocks: a preliminary understanding of gravity and magnetic fields     

Jiayong Yan  Kun Zhang  Guangming Fu  Fan Luo  Hao Wang  Guang Qi 《《地质学报》英文版》2018,92(Z1):222-225

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Cosmogenic 26Al/10Be Burial Dating of the Uplift Rate of Southern Qinling Mountains since the Middle Pleistocene     

LU Yiming  SUN Xuefeng  TU Hu  ZENG Qiongxuan  XU Xinghua 《《地质学报》英文版》2018,92(4):1674-1675

正Objective The Qinling Mountains(QM)in Central China is a natural barrier that corresponds to the boundary between the southern and northern climate and environment(Gong Hujun et al.,2017).Northern QM is relatively steep,and southern QM is in contrast relatively low and gentle.Investigations have shown that the average uplift rate of  相似文献   

考虑方位漂移的水平井井眼轨道设计   总被引：1，自引：1，他引：0       下载免费PDF全文

王世栋  张志刚  耿雪樵  于彦江  陈奇 《探矿工程》2018,45(7):14-18

目前,深层页岩气水平井在钻井过程中经常出现方位漂移的问题,方位漂移严重影响了水平井的井眼轨迹控制,进而影响水平井的准确中靶。在现场施工中,通常根据施工区以前的钻井经验,在进行定向造斜时,先估计出一个“方位超前角”,这种现场的做法有着很大的不确定性,并且可能出现较大误差。本文提出了考虑方位漂移的水平井井眼轨道优化设计的方法,解决了仅凭现场经验给出的“超前角”不准确的问题。考虑方位漂移的水平井井眼轨道优化设计按照井段划分,将地层因素与井身剖面结合起来求取井段的平均方位漂移率。根据该方法研制开发了考虑方位漂移的水平井井眼轨道优化设计软件,并通过举例进行了验证,证明了方法是可行的。  相似文献   

地质导向技术在L型煤层气水平井 T-P05井中的应用          下载免费PDF全文

郭宝林  李琪  张兴龙  聂涛  于建克  李盟国 《探矿工程》2018,45(1):9-13

通过分析山西L型煤层气水平井的技术难点,着重建立造斜着陆与水平段导向两大导向模型,形成了以标志层划分与对比、地层倾角推算、地质建模和实时轨迹控制四个方面为主的L型煤层气水平井地质导向技术流程,该技术在T-P05井的成功应用,不仅丰富了煤层气水平井地质导向技术的内容与方法,更进一步验证了该技术在现场具有较强的可操作性和良好的应用前景,值得大力推广。  相似文献   

贵州松桃高地特大型富锰矿床主要地质特征   总被引：1，自引：1，他引：0       下载免费PDF全文

袁良军  周琦  姚希财  谢小峰  杜远生  张遂  潘文  谢兴友  王萍  徐源 《贵州地质》2018,35(4):314-318

位于贵州铜仁松桃国家锰矿整装勘查区内的高地富锰矿床,(332)+(333)类碳酸锰富锰矿石资源量达7 166. 84万吨,锰平均品位25. 75%,矿体平均厚度4. 52 m,富锰矿体赋存于总资源量达1. 61亿吨的高地超大型锰矿床之中,由一个单一的富锰矿体构成,是我国新发现的首个特大型富锰矿床,富锰矿资源量相当于我国富锰矿资源量总和的2倍。成因类型属古天然气渗漏沉积型锰矿床,富锰矿产于古天然气渗漏沉积成矿系统中心相区。高地富锰矿床地处独特的"新月形"南华纪早期李家湾-高地-道坨(Ⅳ级)地堑盆地中心,菱锰矿体中均出现以块状构造夹被沥青充填的气泡状富菱锰矿石。地表燕山期北北东向的断裂构造十分发育,但主要为上陡下缓犁式正断层,未触及高地深部隐伏巨型锰矿体,以致富锰矿体保存亦十分完整,易于开发利用。  相似文献