川西坳陷中段新场地区天然气研究及气源对比   总被引：3，自引：1，他引：2  

田军  沈忠民  吕正祥  罗小平 《四川地质学报》2009,29(1):20-23

经过大量学者多年的研究总结,川西坳陷中段新场地区具备良好的生、储、盖等成藏组合。结合地质背景及碳同位素、轻烃的研究,认为新场地区天然气主要是Ⅲ型干酪根的煤型气,气藏主要分布在上三叠系的须二段和须四段,以及中侏罗系、上侏罗系地层中。  相似文献   

普光气藏长兴—飞仙关组碳酸盐岩C、O同位素、微量元素分析及古环境意义   总被引：3，自引：0，他引：3  

徐立恒  陈践发  李玲  马广宇  刘钰丹 《地球学报》2009,30(1):103-110

以普光气藏普光2、6井为研究对象,取其长兴—飞仙关组116个白云岩样品,分析C、O同位素及微量元素特征,判断古海水盐度,并与沉积特征相结合,研究其沉积环境。分析得d13C与盐度Z呈正相关关系。普光2井飞仙关组一段、二段—飞仙关组三段,盐度及d13C、Sr、P、Ti、Mn值呈逐渐增大的趋势,沉积相经边缘浅滩—潮坪的演化进程。飞仙关组一段、二段时期,其d13C及Sr、P、Ti、Mn值较低、d13C波动小,反映海平面变化不大,且遭到淡水的冲淋,导致盐度降低;飞仙关组三段时期,处于潮坪环境, 气候干燥炎热,淡水不断地被大量蒸发,其结果导致盐度增大,d13C及Sr、P、Ti、Mn值增高,在此期间海平面变化较明显,造成d13C波动较大。碳同位素值在长兴组末期发生突降,其原因可能是在二叠纪末, 大量狭盐生物死亡而造成的。  相似文献   

闽西北铅锌矿成矿特征及控矿条件浅析     

张国华 《化工矿产地质》2009,31(2):97-104

闽北地区属华南褶皱系的一部分,其中铅、锌为区内优势矿种,广泛分布于前震旦纪变质岩系中,尤其以前震旦纪龙北溪组的黑云斜长变粒岩、云母片岩、石英片岩中最为多见。其成矿特征可分为热液型铅锌矿床、充填交代型铅锌矿床及沉积变质热液叠加型铅锌矿床。其形成受地层、岩浆、构造（以断裂构造为主）控制较为明显,前震旦系变质岩系中的绿片岩、压扭性断裂及前震旦系变质岩系与岩体的接触带及其附近应是本区铅锌矿床找矿的主要方向。  相似文献   

反倾层状岩质边坡内开挖隧道引发边坡失稳与隧道塌方的机制和治理研究     

黄志煌  李天斌 《地质灾害与环境保护》2009,20(4):76-80

在反倾层状边坡内,开挖边坡并修筑隧道洞口后,出现岩体从隧道掌子面整体挤出和洞顶塌方现象,并导致边坡出现后缘拉裂、坡体内出现多处裂缝和岩块崩塌等坡体失稳迹象。通过对该边坡失稳和隧道塌方的勘察和机制分析,确定该坡体的变形破坏模式,提出针对性治理方案。  相似文献   

鲁东地区侵入岩形成时代和期次划分——锆石SHRIMPU—Pb年龄的证据   总被引：1，自引：0，他引：1  

王世进  ;王来明  ;万渝生  ;张成基  ;宋志勇  ;王金光 《山东地质》2009,(12):8-20

鲁东地区前寒武纪侵入岩其侵入活动集中于新太古代和新元古代,均遭受不同程度的区域变质和韧性剪切带的改造,形成一套花岗质片麻岩类。新太古代早期TTG质花岗岩分布于胶北隆起区莱州一栖霞一带,经受了区域变质作用,形成一套灰色片麻岩,锆石内核SHRIMPU—Pb年龄2726—2707Ma基本代表岩浆结晶年龄,锆石变质边为2500Ma;古元古代侵入岩——莱州基性一超基性岩组合形成于1900～1850Ma左右,锆石SHRIMPU—Pb年龄（1852±9）Ma,（1868±11）Ma;新元古代侵入岩主要为花岗闪长质-二长花岗质片麻岩,出露于胶南-威海造山带,锆石U～Pb定年结果集中为892～605Ma,其中荣成超单元锆石SHRIMPU—Pb年龄720～780Ma。中生代侵入岩以花岗岩类为主,集中出露于半岛北部和东南沿海一带。燕山早期侵入岩文登超单元、垛崮山超单元、玲珑超单元锆石SHRIMPU—Pb同位素年龄值集中在167～150Ma;燕山晚期侵入岩大店超单元锆石SHRIMPU～Pb年龄120±4Ma,崂山超单元锆石SHRIMPU～Pb同位素年龄值为（120±2）～（114±2）Ma。  相似文献   

Computer thermodynamic modeling of the transport and deposition of Sb and Au during the formation of Au-Sb deposits   总被引：1，自引：0，他引：1  

A.A. Obolensky  L.V. Gushchina  A.S. Borisenko  A.A. Borovikov  P.A. Nevol&#x;ko 《Russian Geology and Geophysics》2009,50(11):950-965

Using the Chiller computer program, we performed modeling of the mechanisms of the joint transport and deposition of Au and Sb from various ore-forming solutions during the formation of Au-Sb deposits. Three models are considered by the example of the Uderei Au-Sb deposit in the Yenisei Ridge: (1) simple cooling (cooling only), (2) iso-enthalpy boiling (P = f(T)), and (3) solution–rock interaction (rock titration model). The behavior of Sb(III) and Au(I) in the system Au–Sb–Fe–Cu–Pb–Zn–As–H₂O–Cl–H₂S–CO₂ under hydrothermal conditions was studied. It is shown that both weakly alkaline (near-neutral) and reduced acidic Fe_aq²⁺-enriched low-chloride high-CO₂ and high-chloride hydrothermal solutions play a crucial role in the formation of gold parageneses of Au-Sb ores.  相似文献   

Genesis of Tertiary Magnetite–Apatite Deposits,Southeast of Zanjan,Iran     

Hossein Azizi  Behzad Mehrabi  Afshin Akbarpour 《Resource Geology》2009,59(4):330-341

Magnetite–apatite deposits in the Alborz volcano–plutonic belt, southeast Zanjan, in Iran, have blade, lenzoid, and vein forms, which extend in an E‐W direction. There are many magnetite–apatite veins and veinlets in this region, and some of them are economically important, such as Zaker, Morvarid, Sorkheh–Dizaj, and Aliabad. The sizes of the vein orebodies vary between 2 and 16 m in width, 10–100 m in length, and 5–40 m in depth. Microscopic examination of thin sections and polishes indicate that they are composed of magnetite and apatite, with minor amounts of goethite, hematite, actinolite, quartz, muscovite–illite, talc, dolomite, and calcite. The geochemistry and mineralogy of the granitic host rock reveals that it is calc‐alkaline and I‐type. Field observations, mineral paragenesis, the composition of the orebodies, and the composition of the fluid inclusions in the apatite minerals with low salinity (less than 20 wt.% NaCl equivalent) indicate that these magnetite veins were hydrothermally generated at about 200–430°C and are not related to silica–iron oxide immiscibility, as are the major Precambrian magnetite deposits in central Iran.  相似文献   

Petrogenesis of extension-related alkaline volcanism in Karaburhan (Sivrihisar–Eskisehir), NW Anatolia, Turkey     

Ender Sar&#x;fak&#x;olu  Hayrettin zen  Chris Hall 《Journal of Asian Earth Sciences》2009,35(6):502-515

Alkaline lavas were erupted as phonolites and trachytes around Karaburhan (Sivrihisar–Eskisehir, NW Anatolia) within the Izmir–Ankara–Erzincan suture zone. These volcanic rocks were emplaced as domes, close and parallel to the ophiolite thrust line. According to ⁴⁰Ar/³⁹Ar geochronological analyses of sanidine crystals from the phonolites, the age of the alkaline volcanics is 25 Ma (Late Oligocene–Early Miocene).The flow-textured phonolites are porphyritic and consist mainly of sanidine, clinopyroxene, and feldspathoid crystals. The clinopyroxenes show compositional zoning, with aegirine (Na_0.82–0.96Fe⁺³_0.68–0.83) rims and aegirine–augite cores (containing calcium, magnesium, and Fe⁺²). Some aegirine–augites are replaced with sodium-, calcium-, and magnesium-rich amphibole (hastingsite). Feldspathoid (hauyne) crystals enriched with elemental Na and Ca have been almost completely altered to zeolite and carbonate minerals. The fine-grained trachytes with a trachytic texture consist of feldspar (oligoclase and sanidine) phenocrystals and clinopyroxene microphenocrystals within a groundmass made up largely of alkali feldspar microlites.Although there are some differences in their element patterns, the phonolites and trachytes exhibit enrichment in LILEs (Sr, K, Rb, Ba, Th) and LREEs (La, Ce, Pr, Nd) and negative anomalies in Nb and Ta. These geochemical characteristics indicate a lithospheric mantle enriched by fluids extracted from the subduction component. In addition, the high ⁸⁷Sr/⁸⁶Sr (0.706358–0.708052) and low ¹⁴³Nd/¹⁴⁴Nd (0.512546–0.512646) isotope concentrations of the alkaline lavas reflect a mantle source that has undergone metasomatism by subduction-derived fluids. Petrogenetic modeling indicates that the alkaline lavas generated from the subduction-modified lithospheric mantle have undergone assimilation, fractional crystallization, and crustal contamination, acquiring high Pb, Ba, Rb, and Sr contents and Pb isotopic compositions during their ascent through the thickened crust in an extensional setting.  相似文献   

水热条件对纤蛇纹石纳米管合成的影响研究     

马国华  彭同江  李明 《岩石矿物学杂志》2009,28(5):480-484

采用水热法在不同反应条件下合成了一系列纤蛇纹石纳米管.利用红外吸收光谱、扫描电镜和透射电镜系统地研究了水热反应中,反应温度、Si/Mg比、反应时间等不同反应参数对合成纤蛇纹石纳米管的晶体生长及其结构的影响.结果表明,温度的升高、Si/Mg比趋近0.68及反应时间的延长均有利于纤蛇纹石的生长,并获得最佳条件下合成的纤蛇纹石条件.  相似文献   

浙江泰顺龟湖叶腊石矿床热液蚀变短波红外光谱分析   总被引：1，自引：0，他引：1  

翟世达  段士刚  孙鹏  王旭辉  张炎  梅世勇 《矿床地质》2022,41(1):189-201

蚀变岩帽与斑岩体关系密切,具有形成斑岩-浅成低温热液型矿床的潜力.位于浙闽交界的龟湖地区发育规模巨大的蚀变岩帽(>30 km2),形成了龟湖超大型叶腊石矿床,矿体属于岩帽的一个分带.矿床及其围岩蚀变主要由粒度微小或隐晶质的层状硅酸盐蚀变矿物组成,矿物之间差别极为细微,仅凭肉眼难以区分.短波红外光谱技术可以有效识别这些蚀...  相似文献