Geochemistry and Hf Isotopes Characteristics and Geological Significance of Latest Early Permian Granodiorite of Langshan Area,Inner Mongolia     

Yang Liu  Wenlong Wang  Xuejian Teng  Shuo Guo  Fei Teng  Peng He  Jian Tian  Xiaolong Duan 《地球科学进展》2019,34(4):366-381

The Langshan area is located in the west of Inner Mongolia, southwest of the Solonker ophiolite belt, which is the ideal workplace to study tectonic-magmatic evolution and geodynamics background in Late Paleozoic because of the intense magmatism. LA-ICP-MS Zircon U-Pb ages yielded the formation time of granodiorite of Sharichulu and Moruogu granitic pluton (278.07±0.66) Ma and (278.05±0.69) Ma, respectively, forming in the latest early Permian. Geochemical characteristics showed that the Zhalashan granites were high-K calc-alkaline (SiO₂：63.76%～67.88%;K₂O：2.74%～4.02%) and weak peraluminous rocks (A/CNK：0.94～1.07) with moderate Mg# values (38.98～47.53). In addition,it exhibited LILE and LREEs enriched, HFSE and HREEs depleted with slight Eu anomaly, and all of the above-mentioned indicated the characteristics of I-type granites and arc-related. Zircon Hf isotope showed that the scatter εHf（t）values varied from -0.6～-7.5, which suggests a mixed magma source of old continental crust with a small involvement of mantle components. Together with regional geological background,the authors hold that the Latest early Permian granodiorite of Langshan area formed in an active continental margin setting under the background of southward subduction of the Paleo-Asian Ocean which were not close at that time.  相似文献   

试用系统评价技术分析断裂的优势性     

王新建  罗国煜  阎长虹  许宝田 《地球科学与环境学报》2002,24(2):21-25

首先分析了运用系统评价技术判断断裂相对优势性方法的合理性,通过类比,建立了断裂优势性系统评价流程图及数学模型。并以评价对南京地区区域稳定性有影响的断裂的优势性为例,对结果进行了对比分析;对系统评价这一应用的优点、下一步的工作及相关问题进行了讨论。事实说明,这一运用是合理的,适用的,从学科的长远发展来看也是必要的。  相似文献   

小秦岭南缘活动剪切带与金矿关系     

梁文艺 《地球科学与环境学报》1994,(3)

本文论证了小秦岭金矿受华北地台南缘活动剪切带长期演化、有序叠加构造的控制，并提出了新的成矿模式．  相似文献   

Introduction to plasma astrophysics and cosmology     

Anthony L. Peratt 《Astrophysics and Space Science》1995,227(1-2):3-11

The year 1996 marks the Centennial Celebration of the founding of Plasma Astrophysics and Cosmology; its origins may be traced to the seminal research first published by Kristian Birkeland in 1896. This special workshop issue reports on advances in issues of importance to the plasma universe; topics as timely as when first raised a century ago.  相似文献   

Review of the development of laser fluorosensors for oil spill application     

Brown CE  Fingas MF 《Marine pollution bulletin》2003,47(9-12):477-484

As laser fluorosensors provide their own source of excitation, they are known as active sensors. Being active sensors, laser fluorosensors can be employed around the clock, in daylight or in total darkness. Certain compounds, such as aromatic hydrocarbons, present in petroleum oils absorb ultraviolet laser light and become electronically excited. This excitation is quickly removed by the process of fluorescence emission, primarily in the visible region of the spectrum. By careful choice of the excitation laser wavelength and range-gated detection at selected emission wavelengths, petroleum oils can be detected and classified into three broad categories: light refined, crude or heavy refined.

This paper will review the development of laser fluorosensors for oil spill application, with emphasis on system components such as excitation laser source, and detection schemes that allow these unique sensors to be employed for the detection and classification of petroleum oils. There have been a number of laser fluorosensors developed in recent years, many of which are strictly research and development tools. Certain of these fluorosensors have been ship-borne instruments that have been mounted in aircraft for the occasional airborne mission. Other systems are mounted permanently on aircraft for use in either surveillance or spill response roles.  相似文献   

Contribution of tsunami data analysis to constrain the seismic source: the case of the 1693 eastern Sicily earthquake     

Stefano Tinti  Alberto Armigliato  Elisabetta Bortolucci 《Journal of Seismology》2001,5(1):41-61

The January 11, 1693 eastern Sicilyearthquake is comparable only with the December 28,1908 Messina Straits event in the Italian seismichistory as regards magnitude (M _L 7), level ofdestruction and number of victims. The shock generateda strong tsunami, which hit the entire eastern coastof Sicily and particularly the town of Augusta. Theproblem of which fault was responsible for theearthquake is still open. Several hypotheses have beenformulated in the literature on the basis of differentkinds of geological, macroseismic and tectonic data,but a general agreement has not been reached yet. Animportant contribution to the discussion may come fromthe analysis of the tsunami data. In two previouspapers (Piatanesi et al., 1996; Piatanesi and Tinti,1998), the hydro-dynamical study of the tsunami basedon finite-element (FE) numerical simulations wascarried out taking into consideration mostlytheoretical faults, i.e. faults selected for theirsignificance in tsunami generation irrespective of thecorresponding geological evidence. This paper has tobe considered the continuation of the mentioned works.We have studied new sources proposed in theliterature, consistent with macroseismic data and/orgeological observations, and simulated thecorresponding tsunamis. We also built a new FE gridintroducing significant improvements in the coastlinerepresentation, and developed and applied a newalgorithm in order to account for the effect of thesea-bottom topography on the tsunami initialcondition. Some of the examined faults are located inthe Scordia-Lentini (SL) graben region and interceptthe coastline, others are placed in correspondencewith the Hyblaean-Malta (HM) escarpment and runparallel or sub-parallel to the coast. The conclusionof our work is that none of these faults respectsfully the available observations on tsunami, and thatthe faults exhibiting the best fit are those placed inthe SL region. It is worth stressing that our resultsare important for the assessment of seismic andtsunami hazard/risk in eastern Sicily, keeping also inmind that the 1693 earthquake has been selected as thereference event for an earthquake-scenario study inCatania and in south-eastern Sicily, called `CataniaProject', funded by CNR/GNDT (Consiglio Nazionaledelle Ricerche/Gruppo Nazionale Difesa dai Terremoti).  相似文献   

青藏高原北部的第四纪断层运动   总被引：16，自引：0，他引：16  

赵国光 《中国地震》1996,12(2):109-118

近１０年来，通过详细考察和填图工作，对青藏高原北部的第四纪活动构造及断层运动取得了大批新资料，在最近在中法合作研究中，对东昆仑活动断裂带及邻区又进行了较深入的调查，本文以上述新资料为基础，简要讨论了青藏高原北部第四纪活断层的运动学和动力学基本特征本区重要的活动断裂可划分为下述３类，（１）大规模的弧形左旋走滑断裂带，其中包括青藏高原北部边缘的阿尔金活动断裂带，昌马活动断裂带及海原活动断裂带，中部的东  相似文献   

冀中坳陷北部河西务断层结构及新近纪以来的活动特征分析     

毛黎光  田建章  张宏伟  张传宝  王鑫  肖安成 《高校地质学报》1997,25(4):578

河西务断层是渤海湾盆地冀中坳陷北部地区一条重要的控盆断裂，新近纪—第四纪时期渤海湾盆地整体进入热沉降 阶段后，该断层仍然存在构造活动，2018年在河北永清县发生的地震就是由该断层的活动所引发。文章利用地震数据对河 西务断层的结构特征和新近纪以来的活动特征进行分析，结果表明，河西务断层新近纪以来具有右旋走滑的张扭特征，主 断层在剖面上具有负花状结构，平面上具有分段性，北段和南段兼具右旋走滑和拉张的特征，中段则主要表现为右旋走滑 特征。运动学模型表明，这种分段差异性主要由各段主断层走向和块体走滑运动方向的夹角所决定。  相似文献   

多煤层小断层特征差异性分析     

王恩营 《中国煤田地质》1997,9(4):4-6

以多煤层区采掘资料为依据，通过对不同煤层间小断层特征的比较研究，论证了煤岩层岩性、厚度及组合在煤层小断层发育中的作用，提出了“岩层力学性质”的概念，对多煤层开采矿井中小断层的研究和预测有一定的指导意义。  相似文献   

断层泥显微结构特征与断层滑动习性的研究     

张秉良  方仲景  向宏发  段瑞涛 《华南地震》1996,(4)

天然断层中普遍存在含有粘土矿物的断层泥，大量的实验研究和野外观察证实，不同应变速率的变形作用在断层泥中留下了特殊的显微构造特征（如褶皱、眼球状构造和膝折等）。因此，我们可以根据断层泥的变形特征，来推测变形时断层的滑动方式和次序。尽管这一方面的研究还处于探索阶段，但它可能将成为研究活断层的一个新途径。  相似文献