Dunites of the Inagli massif (Central Aldan), cumulates of lamproitic magma     

I.F. Chaika  A.E. Izokh 《Russian Geology and Geophysics》2018,59(11):1450-1460

We consider a hypothesis for the origin of PGE-bearing ultramafic rocks of the Inagli massif (Central Aldan) through fractional crystallization from ultrabasic high-potassium magma. We studied dunites and wehrlites of the Inagli massif and olivine lamproites of the Ryabinovy massif, which is also included into the Central Aldan high-potassium magmatic area. The research is focused on the chemistry of Cr-spinels and the phase composition of Cr-spinel-hosted crystallized melt inclusions and their daughter phases. Mainly two methods were used: SEM-EDS (Tescan Mira-3), to establish different phases and their relationships, and EPMA, to obtain precise chemical data on small (2-100 μm) phases. The obtained results show similarity in chromite composition and its evolutionary trends for the Inagli massif ultramafites and Ryabinovy massif lamproites. The same has been established for phlogopite and diopside from crystallized melt inclusions from the rocks of both objects. Based on the results of the study, the conclusion is drawn that the ultramafic core of the Inagli massif resulted from fractional crystallization of high-potassium melt with corresponding in composition to low-titanium lamproite. This conclusion is consistent with the previous hypotheses suggesting an ultrabasic high-potassium composition of primary melt for the Inagli ultramafites.  相似文献   

Rutile R632 – A New Natural Reference Material for U‐Pb and Zr Determination          下载免费PDF全文

Emelie Axelsson  Jonas Pape  Jasper Berndt  Fernando Corfu  Klaus Mezger  Michael M. Raith 《Geostandards and Geoanalytical Research》2018,42(3):319-338

A new natural rutile reference material is presented, suitable for U‐Pb dating and Zr‐in‐rutile thermometry by microbeam methods. U‐Pb dating of rutile R632 using laser ablation ICP‐MS with both magnetic sector field and quadrupole instruments as well as isotope dilution‐thermal ionisation mass spectrometry yielded a concordia age of 496 ± 2 Ma. The high U content (> 300 μg g^?1) enabled measurement of high‐precision U‐Pb ages despite its young age. The sample was found to have a Zr content of 4294 ± 196 μg g^?1, which makes it an excellent complementary reference material for Zr‐in‐rutile thermometry. Individual rutile grains have homogeneous compositions of a number of other trace elements including V, Cr, Fe, Nb, Mo, Sn, Sb, Hf, Ta and W. This newly characterised material significantly expands the range of available rutile reference materials relevant for age and temperature determinations.  相似文献   

扬子陆块西缘安益南华纪火山岩的厘定及其地质意义     

刘兵  李静  邓仁宏  熊波  关奇  李小军  刘军平  陈光艳  胡绍斌  张虎  李维科  曾文涛 《地质通报》2018,37(11):1980-1990

扬子陆块西缘安益大湾山地区出露一套由变质玄武岩等组成的变质基性火山岩,前人将其归为中元古界,并作为寻找磁铁矿的主要对象。调查发现,安益大湾山变质基性火山岩与下伏浅变质岩系间发育一套稳定沉积的砾岩。应用LA-ICP-MS技术对其底砾岩之上最底部的变质玄武岩进行了锆石U-Pb年龄测定,获得了781.3±1.9Ma的岩浆锆石~(206)Pb/~(238)U年龄加权平均值和1008±14Ma、1142±15Ma、2714±10Ma的继承性岩浆锆石~(207)Pb/~(206)Pb年龄,指示该套变质基性火山岩形成于南华纪,并将其从浅变质岩系中解离出来,对比为澄江组。继承性锆石年龄数据指示,扬子地块西缘安益地区存在新太古界和中元古界物质记录。结合前人研究成果和近来获得的年龄数据,将滇中澄江组的时代界定于820～740Ma,并将南华系的底界界定于820Ma。大湾山中-大型磁铁矿产于扬子地块西缘澄江组的变质基性火山岩中,其主成矿期为南华纪,可能属于热液氧化物-铜-金矿床。  相似文献   

烟台市牟平区废弃矿山地质环境问题及生态修复治理措施          下载免费PDF全文

孙建强  何胜强  张晓亮  黄文渊  哈浩 《山东国土资源》2022,38(10)

本文以烟台市牟平区某废弃矿山为例,介绍了该区域存在的地质环境问题,分析了造成该区域矿山地质环境破坏的原因,以恢复耕地、草地、林地为目的,对区内的现状进行分析,对采坑、残丘、料场提出相应的修复方案。矿山地质环境恢复治理需从科学的角度树立正确的修复理念,落实地貌重塑、土壤重构和植被恢复三大矿山修复核心技术,为矿山地质环境保护与生态恢复治理提供重要的科学依据。  相似文献   

胶东栖霞大霞址断裂南段金矿地质特征及成因研究          下载免费PDF全文

彭雪峰 《山东国土资源》2022,38(11)

近年来胶东栖霞大霞址断裂南段发现了多个金矿床。文章从蚀变带特征、矿体空间展布特征等方面阐述了研究区金矿地质特征;从地层、岩浆岩、构造“三位一体”分析总结了控矿因素;通过与典型矿床的分析对比,认为该区金矿床类型属于构造蚀变岩型,金矿与硅化、绢英岩化、黄铁矿化关系最为密切;结合对成矿物质来源、成矿流体运移、沉淀、富集等的认识,对大霞址断裂金矿的成因进行了总结,建立了成矿模式,提出了下一步找矿建议。  相似文献   

山东济宁任城区采煤塌陷地治理和生态修复研究          下载免费PDF全文

胡龙  沈立  李慢慢  谢琳琳 《山东国土资源》2022,38(12)

在总结和分析山东济宁任城区采煤塌陷地治理现状和治理模式的基础上,辅以具体案例,分析探讨了任城区采煤塌陷地治理存在的主要问题,提出了有针对性的措施和建议,如：加大国土空间规划统筹力度,建立系统治理机制等,为提升采煤塌陷地综合治理和生态修复提供一定的参考。  相似文献   

山东青州王坟地区1∶5万水系沉积物地球化学特征及找矿方向          下载免费PDF全文

董美川  武斌  杜振明  刘继勇  李保卫  夏影 《山东国土资源》2022,38(9)

鲁西近年来陆续发现了多处金及多金属矿床,如沂南铜井、金场,平邑归来庄、磨坊沟,沂源金星头,临朐铁寨等,但对上述地区以外的找矿工作还相对薄弱。王坟地区作为临朐铁寨金银多金属矿区外围地区,具有相似的成矿地质条件。本次研究通过在王坟地区开展的1∶5万水系沉积物测量工作,对其相关成矿元素进行聚类分析、因子分析等地质统计学分析。结果表明,区内Pb、Ag异常规模大,峰值高,富集特征及浓集中心明显,相关元素套合较好。通过地化剖面及探槽工程等手段进行异常查证,所取样品中Pb、Ag等低温热液元素分析结果与异常特征套合较好,本区内沿断裂带找寻Pb、Ag等低温热液元素矿床或矿化体潜力较大。  相似文献   

基于跨断层监测资料的金州断裂活动性研究     

孔祥瑞  翟丽娜  李梦莹  孙庆山  焦明若  王喜龙 《大地测量与地球动力学》2022,42(4):416-420

利用金州地震台跨断层形变观测资料分析金州断裂现今活动特征。长趋势分析结果表明,金州断裂以右旋兼正断为主,活动水平总体较弱。断裂活动分段分析结果表明,北段活动速率高于南段。GPS资料分析表明,2011-03-11日本M_W9.1地震对东北地区应力积累具有缓解作用,结合金州断裂跨断层数据认为,金州断裂在2011~2014年活动速率明显减弱,2014年至今断层活动与其背景资料一致,但活动水平较弱。  相似文献   

菲律宾棉兰老岛2019年4次M_W>6.0地震断层运动模型及库仑应力传输研究     

吴少杰  杨莹辉  王泽根  熊凌艳  陈强  陈静  杨超 《大地测量与地球动力学》2022,42(3):240-246

基于雷达干涉测量技术,利用ALOS-2、Sentinel-1卫星升降轨雷达影像,获得2019-10~12发生在菲律宾棉兰老岛的4次M_W>6.0地震的同震形变场,并以此形变结果为约束,反演得到4次地震的断层运动模型。综合分析发现,此次地震序列由3条断裂的破裂引起,其中2019-10-16和2019-10-31的2次地震为同一发震断裂,2019-10-31地震断层破裂区域位于2019-10-16地震断层破裂的东北延伸段,最大滑动量约为1.1 m,约为2019-10-16地震最大滑动量的2倍。2019-10-29地震由一条独立断层破裂引起,断层最大滑动量约为2.0 m。2019-12-15地震由一条东北向倾斜断层破裂引起,断层最大滑动量约为3.0 m。此外,2019-10-16地震引起2019-10-29地震显著滑动区明显的正向库仑应力传输;而2019-10-29地震显著增加了2019-10-31地震震源区域的库仑应力;前3次地震对2019-12-15地震孕震断层的库仑应力传输总和为负值,说明静态库仑应力传输可能不是此次地震触发的主要诱因。  相似文献   

Evaluation of the Bioavailability of Metals in Sediment from the Southern Coastal Wetland of the Qiantang Estuary by Using Diffusive Gradients in Thin Films Technique     

FENG Weihua  WANG Zhifu  ZHU Wenzhuo  ZHENG Fangqin  ZHANG Dongrong  XU Hengtao 《中国海洋大学学报(英文版)》2022,21(2):375-387

Metal pollution has become an major issue governing the wetland ecosystem health.The southern coastal wetland of the Qiangtang Estuary are facing unusual perturbation due to rapid development along the embayment in recent decades.This study evaluated the bioavailability of metals(Cu,Pb,Cd,Cr and Zn)in the sediment of the southern coastal wetland of the Qiangtang Es-tuary using diffusive gradients in thin films(DGT)techniques and compared with several methods based on total metal content.The results showed that the contents of Cr,Pb,Cd and Cu in sediment,as detected using DGT,were considerably correlated with the exchangeable fraction and the content in Phragmites australis roots,while a weak correlation was observed for Zn.Therefore,DGT analysis could be used to evaluate the bioavailability and potential risk of Cr,Cd,Pb and Cu for P.australis.Quantitative indices,such as DGT concentration,bioaccumulation in P.australis,geoaccumulation index(Igeo)and potential ecological risk index(RI),revealed that Cd was a major potential ecological risk factor along the southern coast wetland of the Qiantang Estuary,especially in the upstream region,which is potentially more vulnerable to the anthropogenic pollution.  相似文献