陇南阳山金矿床流体包裹体初步研究     

刘伟  范永香  余金元  徐立明 《矿产与地质》2003,17(5):616-621

陇南的阳山金矿床是产于泥盆系浅变质岩中的特大型金矿床，通过对该矿床流体包裹体的温度、盐度、密度、成矿压力及δD值等方面的研究，综合特征表明成矿流体具有浅成、中偏碱性和弱还原环境的成矿特点，综合分析认为成矿可能主要与低温热液作用有关。  相似文献   

陇南阳山金矿床流体包裹体研究     

刘伟  范永香  余金元  赵百胜 《华东地质学院学报》2003,26(4):328-336

陇南的阳山金矿床是中国人民武装警察黄金部队近年来在陕甘川交界地带发现的一个特大型金矿床。该矿床 3 0余件样品的流体包裹体分析结果表明 :1.镜下石英中流体包裹体类型丰富多样。据室温状态下流体包裹体的相态、加热状态下流体包裹体的性状及产出特征 ,鉴别出两种成因类型及九种物理状态类型 ;2 .流体包裹体显微测温结果显示本区的均一温度主要集中在 2 60～ 3 10℃ ,2 2 0～ 2 40℃ ,15 0～ 190℃等三个区间 ,流体组份体系接近于NaCl-H2 O -CO2 体系 ,,成矿流体密度估计在 0 .3 5～ 1.0 2 g·cm- 3之间 ,成矿压力估计小于 1Kbar ,流体包裹体盐度估计在 2 .5～ 6.5wb %NaCl之间 ;3 .从流体包裹体成分分析获得的 pH值在 6.91～ 7.1之间 ,还原参数H4 +CO +H2 /CO2 的摩尔数比值在 0 .0 0 9～ 0 .0 5之间 ,具有浅成中偏碱性和弱还原环境成矿特点 ;4.石英中流体包裹体的δD( -SMOW ) 值在 -92 .4‰～ -62 .9‰之间 ,δ1 8O石英 ( -SMOW ) 值在 -3 .0 9‰～ +0 .41‰之间 ,δ1 8OH2O( -SMOW ) 值在 -12 .13‰～ -8.48‰之间。综合分析认为成矿可能主要与低温热液作用有关。  相似文献   

Similarities between Yangshan Harbor area and the Yangtze estuary   总被引：1，自引：0，他引：1  

Li Yuzhong  Chen Shenliang 《地理学报(英文版)》2002,12(4):485-494

By analysis of published papers on the Yangtze estuary and hydrological and sediments data in Yangshan Harbor area, many similarities are found between Yangshan Harbor area and the Yangtze estuary. These similarities include the phenomenon of stagnating flow areas, the distributive characteristics of the highest suspended sediment concentration areas, superficial sediments and shoal bars. The stagnating flow area is the major similarity which causes other similarities. These similarities indicate that: 1) Turbidity Maximum and mouth bars in estuaries are mainly caused by the hydraulic balance of stagnating flow areas of estuaries; 2) The stagnating sand area of sands caused by stagnating flow area often locates on the narrower side of the stagnating flow area; 3) The location (or shape) of fine sediments area caused by stagnating flow area reflects the location (or shape) of the stagnating flow area. Both Yangshan Harbor area and the Yangtze estuary are the important developmental areas in the future (man-made similarity). In-depth studies on these similarities between Yangshan Harbor area and the Yangtze estuary will have momentous theoretical and practical significance.  相似文献   

潮流作用下洋山港水域悬沙和底沙的交换   总被引：2，自引：0，他引：2  

陈沈良  李向阳  俞航  谷国传 《海洋学研究》2008,26(1):11-17

通过对泥沙起动流速、淤积流速和不淤流速的计算,划定了悬沙和底沙交换的各个时段,提出了冲刷悬沙浓度、淤积悬沙浓度和不淤悬沙浓度的概念及其计算方法;继而导出了潮流作用下悬沙和底沙在交换层面上单位面积的日交换量计算式,并用于洋山港水域的冲淤计算。结果表明:自然状况下洋山港水域北部年淤积量为37.5 kg/m2,淤高了1.77 cm/a,属微淤;中部年冲刷量为10.0 kg/m2左右,刷深不超过0.52 cm/a,可认为冲淤平衡;南部年冲刷量为55.5 kg/m2,刷深了2.60 cm/a,属微冲。这一结果与该水域海床的自然冲淤状况相吻合。  相似文献   

甘肃省文县阳山金矿床地质及同位素特征   总被引：6，自引：0，他引：6  

杨贵才  齐金忠  董华芳  郭俊华  李志宏 《地质与勘探》2007,43(3):37-41

阳山金矿床位于陕甘川交界地带,在大地构造位置上属西秦岭南亚带.矿床产于中泥盆统三河口组浅变质岩地层中,受文县弧形构造控制.矿体在平面上呈舒缓波状,在剖面上为脉状、似层状,矿石中金属矿物主要有黄铁矿、毒砂和辉锑矿,金主要以微细粒金赋存于黄铁矿、毒砂和黏土矿物中.矿床的钾-氩、氩-氩、氢、氧、硫、碳同位素研究表明,阳山金矿形成于侏罗纪早期(195Ma),与区域上三叠纪末期-侏罗纪早期的岩浆-构造活动关系密切,其不同于典型的卡林型金矿以及类卡林型金矿,其成矿流体及成矿物质均与岩浆热液活动有关.  相似文献   

Erosion and accretion rates and their associated sediment characters along Ras El Bar coast,northeast Nile Delta,Egypt     

Mahmoud M. El Banna 《Environmental Geology》2007,52(1):41-49

Beach profile data, covering the coast of Ras El Bar, northeast Nile Delta, collected during the years from 1990 to 2002 combined with landsat images for the area and sedimentological investigation have been used to identify beach and nearshore seafloor sediment changes. Along the coast of Ras El Bar, two accretion sectors and one of erosion have been recognized. The first accretion sector is located west of Damietta harbour, where the harbour jetties have halted the littoral transport, while the second one is behind a system of detached breakwaters protecting Ras El Bar resort. Both the two sectors are characterized by growing shoreline with maximum rates ∼15 and 10 m/year, respectively. Also, they have maximum nearshore seafloor accretion rates of ∼18 and 22 cm/year, respectively. The erosion sector is located east of Damietta port and has a maximum rate of shoreline retreat ∼−10 m/year. Erosion of its nearshore seafloor is indicated recording a maximum rate of ∼−20 cm/year. The rate of net sediment volume change in the area indicates shifting of the accretion sector (II) westward, responding to installation of the new breakwaters unit. The two accretion sectors are characterized by dominance of moderately sorted fine sands in their shore area which change seaward into less sorting very fine sands. Beach sands of the eroded sector are poorly sorted medium grain size. The dominant constituents of heavy mineral species in beach and sea-bottom sands are the characteristic assemblages of the Nile deposits. The sands of the eroded zone are relatively enriched in monazite, zircon, tourmaline, garnet, and rutile.  相似文献   

甘肃阳山金矿流体包裹体地球化学和矿床成因类型   总被引：16，自引：19，他引：16  

李晶陈衍景  李强之赖勇杨荣生  毛世东 《岩石学报》2007,23(9):2144-2154

西秦岭造山带内的甘肃阳山金矿是我国最新发现的规模最大的金矿床。矿床受 EW 韧脆性剪切带控制,赋矿围岩为泥盆系碳质碳酸盐-千枚岩-板岩和侵入其中的花岗斑岩脉。流体成矿过程包括:形成石英-绢云母-黄铁矿组合的早阶段,形成石英-黄铁矿-毒砂和石英-毒砂-黄铁矿以及石英-碳酸盐-辉锑矿-自然金组合的主成矿阶段,形成碳酸盐-石英网脉的晚阶段。早阶段流体包裹体以含 CO_2包裹体为主,CO_2含量为7.3%～21.5mol%,均一温度集中于270℃～300℃,盐度<3wt.%NaCl eqv;主阶段发育纯 CO_2包襄体、水溶液包裹体和少量含 CO_2包裹体,均一温度集中于210℃～270℃,盐度集中在<2 wt.%NaCl eqv 和3～5 wt.%NaCl eqv 两个范围;晚阶段只发育水溶液包裹体,均一温度集中在160℃～210℃,盐度<3 wt.%NaCl eqv。主阶段流体包裹体类型的多样性、相似的均一温度和流体盐度的双峰特征均指示流体沸腾现象的存在,其流体包裹体捕获温度为210℃～375℃,压力为85～222MPa;赋矿断层的阀门式活动导致主阶段流体系统交替于静岩和静水压力之间,成矿深度为8.5km 左右,成矿流体系统发育在早侏罗世大陆碰撞造山过程。矿床地质特征类似于卡林型金矿。但赋存于蚀变花岗斑岩中矿体既非造山型,也不同于卡林型,成矿流体具造山型矿床特征。因此,阳山金矿可能代表一种新的金矿类型,建议称为"阳山型金矿"。  相似文献   

Geoarchaeological evidence for dredging in Tyre's ancient harbour, Levant     

Nick Marriner 《Quaternary Research》2006,65(1):164-171

Chrono-stratigraphic data from Tyre's ancient northern harbour delineate extensive dredging practices during the Greco-Roman and Byzantine periods. Radiocarbon dates from four cores consistently cluster between ca. 500 B.C. and 1000 A.D. and indicate rapid rates of sedimentation in the basin, namely ∼10 mm/yr during the Greco-Roman and Byzantine periods, compared to 0.5-1 mm/yr for the period 6000-4000 B.C. Absence of strata between 4000 B.C. and 500 B.C. is not consistent with a natural base-level sediment sink and cannot be interpreted as a depositional hiatus in the high-stand systems tract. Ancient dredging is further corroborated by persistent age-depth inversions within the fine-grained harbour facies. These data support removal of Middle Bronze Age to Persian period sediment strata, with deliberate overdeepening of the harbour bottom by Greco-Roman and Byzantine societies.  相似文献   

贵州赤水地区阳三气藏与断层关系探讨     

吕廷智  李恩文 《贵州地质》2000,17(2):79-85

借鉴四川局对二叠系阳新统断层裂缝型气藏的研究成果,结合贵州赤水地区勘探情况分析了断层与地震异常的关系,讨论了旺隆构造东断块高点及高点之南断层。指出了赤水地区地震异常块基本沿断层走向且位于上盘分布,表明与断支裂缝有密切关系;认为旺隆构造北北西向断层对东断块高点之南的油气影响不大,之南的两条逆断层形成的断垒部分对期探天然气较高点有利,提出了三口初步论证的井位。  相似文献   

甘南阳山金矿床控矿构造的思考     

陈柏林 《地质学报》2023,97(8):2512-2533

阳山金矿床位于甘肃省陇南市文县境内,其大地构造位置处于西秦岭构造带的玛曲- 略阳深大断裂南侧,是西秦岭地区为数有限的大型金矿床之一。该区控矿构造复杂,经过20多年的研究仍然存在很大争议。本文通过对矿区含矿构造的调查结合区域构造环境,重新厘定了含矿构造的特征,并对该矿床控矿构造的相关问题进行了讨论。研究结果显示,阳山金矿床控矿构造是以走向NEE,倾向NNW为主的偏脆性逆冲推覆构造系统,形成于俯冲- 碰撞早期的韧性变形之后。含矿构造与千枚岩的千枚理没有直接的关系,可以与千枚理近于平行,或小角度斜交,或大角度斜交,主要以倾向北的断裂为主,少量为主逆冲断层上盘的倾向南的次级反向逆冲断裂,局部为顺千枚理的层间破裂。含矿构造对岩性没有选择性,但是不同岩性岩石的不同力学性质影响了含矿构造的发育与否和发育程度。阳山金矿区进一步工作中值得思考和关注的问题：① 矿区构造格架上葛条湾- 草坪梁复背斜可能不存在,也未起控矿作用;② 成矿后断裂对矿体空间展布的影响;③ 在勘查编录中对各种构造破碎带需要详细的描述,以明确区分含矿构造与成矿后构造,为构建控矿构造体系准备素材,为进一步找矿预测和勘查工程部署提供技术支撑。  相似文献