首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
1 Introduction According to recent researches, the North China Craton consists of three parts: the eastern block, western block and central zone (Zhao, 2001; Wilde et al., 2002). Paleoarchean continental blocks and zircon residuals have only been found in a few regions, such as Anshan, East Liaoning (Liu et al., 1992; Song et al., 1996; Wan et al., 2002, 2005), Caozhuang, East Hebei (Liu et al., 1992) and Xinyang, West Henan (Zheng et al., 2004), which are mainly distributed in the east…  相似文献   

2.
1. Introduction In recent years, growing attention has been focused on diapirs because of their significance to hydrocarbon accumulation in basins (Barber & Brown, 1988; Martin Hovland et al., 1989; Law et al., 1989; Collier et al., 1990; Lewis et al., 1994; Carmelo Monaco et al., 1996; Hieke et al., 1996; Hieke et al., 1996; Lewis et al., 1996; Limonov et al., 1996; Gallardo & Blackwell, 1999). With more and more effort devoted to the studies of the northern continental marginal basins …  相似文献   

3.
1 Introduction The tectono-thermal evolution of the North China Craton (NCC) in Late Archean to Paleoproterozoic times has long been attractive to many researchers (Wan et al., 2000; Zhao et al., 2000, 2002; Guo et al., 2001; Liu et al., 2002; Zhai and Liu 2003; Zhai, 2004; Yu et al., 2004; Kr?ner et al., 2005; Wilde et al., 2005). Zhao et al. (2000, 2002) proposed a tectono-thermo framework for the evolution of the NCCbased on detailed petrological and geochronological data, and they …  相似文献   

4.
Most metallic mineral deposits formed from hydrothermal fluids,and the mineralization processes include both chemical (e.g.,fluid-rock and fluid-fluid interactions) and physical (e.g.,fluid flow) aspects.More attention has been paid to the chemical processes than the physical ones,even though the latter is equally important in controlling the formation of mineral deposits and their localization.Nevertheless,a number of studies have been carried out regarding the hydrodynamics of fluid flow associated with ore mineralization (e.g.,Cathles,1981,1997;Garven and Raffensperger,1997;Cathles and Adams,2005;Cox,2005;Ingebritsen et al.,2006),and it is timely to evaluate our current understanding on this topic and gaps in knowledge to be addressed in further studies.This special section on “Hydrodynamics of mineralization” contains four papers (Chi and Xue,2011;Xue et al.,2011;Zhang et al.,2011;Ju et al.,2011),which summarize the current status of study in the field,and present a few case studies to highlight the importance of hydrodynamics in the research of mineral deposits.  相似文献   

5.
1 Introduction Since the Guilaizhuang gold deposit was discovered in the 1980s, the Tongshi magmatic complex has attracted attention since it exhibits a spatial-temporal relationship to gold mineralization. In the past ten years, a number of detailed fundamental researches have been carried out on the complex, Guilaizhuang gold deposit and their relationships (Qiu et al., 1994; Lin et al., 1996; Yan et al., 1996; Xu et al., 1999; Kong et al., 2001; Shun et al., 2001). Up to date, some res…  相似文献   

6.
The study of the physicochemical behaviour of colloids and particles in nature has emerged as a scientific problem of critical importance because of the widespread acknowledgement of their significance in controlling the speciation and fate of essential nutrients and contaminants in the aquatic and soil environments (Ledin et al., 1995; Lead et al., 1999, Doucet et al., 200 l; McCarthy et al., 1989; Koterba et al., 1993; Kretzschmar et al., 1999). Se'quaris and Lewandowski (2003) developed a method based on sedimentation and centrifugation steps to fractionate agricultural top soils after suspension in water. However, progress in the field has been limited by the lack of appropriate techniques for the isolation and characterization of colloids and particles in their native form (Lead et al., 1997). The primary difficulties in separation and analysis are colloidal instability and their small size and low concentration. As a result, reliable, unbiased and minimally perturbing methods for sampling and fractionation are primary requirements for the study of colloids and particles if valuable information is to be obtained. In recent years, cross-flow ultra-filtration (CFUF) has become one of the most commonly used techniques for collecting and separating freshwater and marine colloids and particles (Petrus evski et al., 1995; Gustafsson et al., 1999; Benoit et al., 1999; Sigg et al., 2000; Gue'guen et al., 2002; Benedetti et al., 2003). CFUF has hitherto been used for studies of the biogeochemical cycling of a variety of elements, such as carbon (Benner et al., 1992; Santschi et al., 1998), radionuclides (Moran et al., 1992), trace metals (Reitmeyer et al., 1996) and nutrients (Bauer et al., 1996). The purpose of this study was to develop a protocol to fractionate particles in soil, to measure particle size distributions and to quantify chemical characteristics within different particle size fractions.  相似文献   

7.
<正>1 Introduction The technology breakthrough in the exploration of shale gas and tight oil has greatly extended the global fossil fuel resources(Jia et al.,2012;Zou et al.,2012;Qiu et al.,2013).Although shale oil has been the global hot topic in the study of unconventional resources,there are varied definitions with respect to shale oil by different researchers.  相似文献   

8.
http://www.sciencedirect.com/science/article/pii/S167498711400156X   总被引:1,自引:0,他引:1  
<正>Continental reconstructions in Central Asia are represented by orogenesis along some large orogenic belts in the Altaid collage(Fig.1)or Central Asian Orogenic Belt(CAOB),which separate the East European and Siberian cratons to the north from the Tarim and North China cratons to the south(Sengor et al.,1993;Jahn et al.,2004;Windley et al.,2007;Qu et al.,2008;  相似文献   

9.
INTRODUCTIONIn recent years a num ber of detailed m ineralogical- petro-logical studies have been carried out on the UHP and HPmetamorphic belts in the Dabie- Sulu region,central China(see review papers by Jahn,1999;Ernst and L iou,1999;Wallis et al.,1999;Hacker et al.,1996 ;L iou et al.,1996 ;Cong et al.,1994) . Various tectonic evolution models for theUHP belt in the Dabie- Sulu region have been constructed(e.g.,Webb etal.,1999;Hacker et al.,1996 ;Cong et al.,1994) .However,as …  相似文献   

10.
正The exploration depth of sandstone-type uranium deposits worldwide is mostly less than 700 m, and most of them occur in strata of fluvial facies(Adams et al., 1981; Jin et al., 2016; Hou et al., 2017). Only a few small uranium deposits have been reported in aeolian depositional environments(Isachsen et al., 1955; Li et al.,  相似文献   

11.
Acyclic Alkanes in the Soil over Heshang Cave in Qingjiang, Hubei Province   总被引:1,自引:0,他引:1  
Biomarkers have been widely used to exploreglobal change such as paleocli mate and paleovegeta-tion based on the analyses of marine sedi ments( Volkman et al ., 1995 ) , lacustrine sedi ments(Sheng et al ., 1999) , snow and ice ( Xie et al .,1999) ,peat (Xie et al .,2004) ,and stalagmites (Xieet al ., 2005 , 2003a) . Research into biomarkers inChina has been conducted in many soils . Aseries ofbiomarkers were identified from the Jiuzhoutaipaleosol-loess profilein Lanzhou,andn-alkanes werepr…  相似文献   

12.
Fluid inclusions are minute sealed fluid droplets in minerals,often less than 10 μm in diameter.They are commonly trapped in diagenetic cements or coalesced fractures in minerals,such as quartz,feldspar and calcite(Roedder,1984).Following the basic norm for fluid inclusion analysis,the“Roedder's Rules”(Roedder,1984),fluid inclusions have been widely used in reconstructing paleofluid evolution history within a reservoir in petroliferous basin(Bourdet et al.,2012).  相似文献   

13.
1 Introduction The Jiufotang Formation is one of the most fossil- productive Early Cretaceous deposits of China. It overlies the famous Yixian Formation from which many important taxa were found (Ji et al., 2004; Chang et al., 2003; Zhou et al., 2003). In addition to other vertebrates, pterosaurs, the first flying reptiles in Earth history, are also abundant in the Jiufotang Formation. At present, nine species belonging to five genera have been reported from the Jiufotang Formation. The…  相似文献   

14.
正The Appalachian orogen in North America is currently considered to be a Paleozoic accretion-type orogenic belt,or a collage,formed by collision of many ancient blocks between Laurentian and Gondwanan margins (Williams,1979;Williams et al.,1988;van Staal et al.,2007).Recently,major progress has been made in understanding the characteristics and tectonic evolution of the outboard peri-Laurentian and peri-Gondwanan terranes of the Iapetus Ocean (van Staal et al.,2009,2012).  相似文献   

15.
Several thrust faults have been mapped in theYanshan belt ,as the thrust structure was first iden-tified by Wong (1928) (Ji et al .,2005 ; Wang et al .,2005a ;Davis et al .,2001 ,1998 ; Yang et al .,2001 ;Zheng et al ., 2000 ; Chen, 1998 ; Zhang et al .,1986 ; He ,1957 ;Chern and Hsiung,1935) .Becausethe Archean basement was widely involved in thethrust systemof the Yanshan belt ,domestic popularrecognition emphasized the thick-skinned characteris-tics and li mited horizontal displacement…  相似文献   

16.
INTRODUCTIONThe Permian-Triassic ( Tr/P) boundary , datedto be (251 .4±0 .3) Ma ago ,is marked by the mostdrastic mass extinction of organisms in the Phanero-zoic .In order to explore the pattern and the cause ofthe mass extinction,extensive research has been fo-cused on biostratigraphy , isotopic chronostratigra-phy , event stratigraphy , ecostratigraphy and se-quence stratigraphy (Payne et al .,2004 ; Reichowetal .,2002 ; Yin et al .,2001 ;Jin et al .,2000 ;Zhanget al .,1996 ,1995 ;…  相似文献   

17.
1 Introduction Voluminous literature has resulted from study of the geology and tectonic evironments of post-orogenic granitoids in eastern Tianshan (He et al., 1995; Han et al., 1997; Gu et al., 1999, 2001; Li et al., 2003; Chen et al., 2004). Previous contributions (Hu et al., 1997; Li et al., 2003) indicate that major events of continental collision in northern Xinjiang occurred around 300 Ma. Then, the tectonics converted from compression to extension, resulting in the uplifting of th…  相似文献   

18.
Melt and fluid inclusions were studied in the minerals of Cenozoic olivine melanephelinites from the Chukchi Peninsula, Russia.The rock contain several generations of olivine phenocrysts varying in composition at mg=0.88~0.77.The phenocrysts bear fluid and melt inclusions recording various stages of melt crystallization in volcanic conduits and shallow magma chambers.Primary fluid inclusions are CO_2-dominated with a density of up to O.93 g/cm~3.All fluid inclusions are partially leaked,which is indicated by haloes of tiny fluid bubbles around large fluid inclusions in minerals.Melt inclusions contain various daughter crystals,which were completely resorbed in thermometric experiments at about 1230℃.Assuming that this temperature corresponds to the entrapment conditions of the CO_2 fluid inclusions,the minimum pressure of the beginning of magma degassing is estimated as 800MPa.Variations in the compositions of homogenized silicate melt inclusions indicate that olivine was the earliest crystalline phase followed by clinopyroxene,nepheline and orthoclase.This sequence is in agreement with the mineralogy of the rocks.The melts are strongly enriched in incompatible trace elements and volatiles(in addition to CO_2,high C1,F,and S contents were detected).There are some differences between the compositions of melts trapped in minerals from different samples.Variations in SiO_2,FeO,and incompatible element contents are probably related to melt generations at various levels in a homogeneous mantle reservoir.  相似文献   

19.
<正>1 Introduction Many high yield shale gas areas in the World are discovered carbon isotope reversals:Barnett,Fayetteville(Zumberge et al.,2012),Marcellus(Tilley et al.,2013),Haynesville(Ferworn et al.,2008),Albany shale gas(Gao et al.,2014),Utica shale gas(Xia et al.,1999;Xia et al.,2012;Xia et al.,2013),the Foothills(Tilley et al.,2011),  相似文献   

20.
正Objective LGM is a critical climate period in the late Quaternary and is the most recent extreme cold event.Clark et al.(2009)used 4271 14C records and 475 cosmogenic nuclide datings to define LGM be in 26.5–19.0 ka BP.LGM age often changes with time in different regions(Mix et al.,2001;Zhang Zhigang et al.,2015).However,LGM has not been described to date in the Beijing region.During our field work in 2015–2017,LGM event stratigraphy was  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号