东北太平洋胡安·德富卡隆起西翼晚第四纪以来的碳酸盐记录     

陈荣华  赵庆英  Alan C Mix  王小波 《海洋地质与第四纪地质》2005,25(1):41-46

通过对东北太平洋胡安·德富卡隆起西翼沉积柱样中的碳酸盐含量和浮游有孔虫氧同位素测试以及浮游有孔虫丰度、溶解指数和粗组分的统计,发现在晚第四纪约65 ka以来碳酸盐含量变化幅度大(0 4%~77 2%),相差非常悬殊,但其变化未呈现出冰期时溶解作用减弱、间冰期时溶解作用强烈这样明显的旋回性。粗组分分析结果显示,地层中有明显的浊流沉积发育。另外,碳酸盐含量和浮游有孔虫丰度分析结果揭露了研究区的 CCD在3 500 m左右。研究认为,在约65 ka来水深浅于3 500 m的区域碳酸盐含量的无规律性变化应与浊流沉积影响有直接的关系,而水深深于3 500 m的区域碳酸盐含量主要受控于深海碳酸盐的溶解作用。  相似文献   

黔南台地罗甸末期—冷坞期海平面变化特征   总被引：2，自引：0，他引：2  

刘家润  杨湘宁  施贵军  孙历 《高校地质学报》2004,10(2):275-282

研究结果表明,贵州南部台地相区二叠纪罗甸末期—冷坞期的海平面经历了连续7次三级旋回升-降的变化过程,这一过程可分为以早期上升较慢为特点(包括第1～3次升降旋回)和以早期上升较快为特点(包括第4～7次升降旋回)的两个不同阶段,其中以海平面第1次升降旋回的早期上升最慢,第4次的最快;海平面变化期间的海面始终都位于台地边缘坡折带之上,而最后一次海平面下降叠加东吴运动导致海水退出台地。  相似文献   

Influence of partial confinement and Holocene river formation on groundwater flow and dissolution in the Florida carbonate platform          下载免费PDF全文

J. D. Gulley  J. B. Martin  P. Spellman  P. J. Moore  E. J. Screaton 《水文研究》2014,28(3):705-717

Much of what is known about groundwater circulation and geochemical evolution in carbonate platforms is based on platforms that are fully confined or unconfined. Much less is known about groundwater flow paths and geochemical evolution in partially confined platforms, particularly those supporting surface water. In north‐central Florida, sea level rise and a transition to a wetter climate during the Holocene formed rivers in unconfined portions of the Florida carbonate platform. Focusing on data from the Santa Fe River basin, we show river formation has led to important differences in the hydrological and geochemical evolution of the Santa Fe River basin relative to fully confined or unconfined platforms. Runoff from the siliciclastic confining layer drove river incision and created topographic relief, reorienting the termination of local and regional groundwater flow paths from the coast to the rivers in unconfined portions of the platform. The most chemically evolved groundwater occurs at the end of the longest and deepest flow paths, which discharge near the center of the platform because of incision of the Santa Fe River at the edge of the confining unit. This pattern of discharge of mineralized water differs from fully confined or unconfined platforms where discharge of the most mineralized water occurs at the coast. Mineralized water flowing into the Santa Fe River is diluted by less evolved water derived from shorter, shallower flow paths that discharge to the river downstream. Formation of rivers shortens flow path lengths, thereby decreasing groundwater residence times and allowing freshwater to discharge more quickly to the oceans in the newly formed rivers than in platforms that lack rivers. Similar dynamic changes to groundwater systems should be expected to occur in the future as climate change and sea level rise develop surface water on other carbonate platforms and low lying coastal aquifer systems. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

PETROLEUM GEOLOGY     

《Abstract of Chinese Geological Literature》2014,(3)

正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.)  相似文献   

Exsolution of dolomite and application of calcite–dolomite solvus geothermometry in high‐grade marbles: an example from Skallevikshalsen,East Antarctica     

H. MIZUOCHI  M. SATISH‐KUMAR  Y. MOTOYOSHI  K. MICHIBAYASHI 《Journal of Metamorphic Geology》2010,28(5):509-526

Calcite–dolomite solvus geothermometry is a versatile method for the estimation of metamorphic temperature because of its simplicity. However, in medium‐ to high‐grade metamorphic rocks the accuracy of estimating temperature by the integration of unmixed dolomite and calcite is hampered by the heterogeneous distribution of unmixed dolomite, difficulties in distinguishing between preexisting and exsolved dolomite and demarcating grain boundaries. In this study, it is shown that calcite–dolomite solvus thermometry can be applied to calcite inclusions in forsterite and spinel for the estimation of peak metamorphic temperature in granulite facies marbles from Skallevikshalsen, East Antarctica. The marbles are comprised of a granoblastic mineral assemblage of calcite + dolomite + forsterite + diopside + spinel + phlogopite ± apatite, characteristic of granulite facies metamorphic conditions. Forsterite, spinel and apatite frequently contain ‘negative crystal’ inclusions of carbonates that display homogeneously distributed dolomite lamellae. On the basis of narrow ranges of temperature (850–870 °C) recorded from carbonate inclusions compared with the range from matrix carbonate it is regarded that the inclusion carbonates represent a closed system. Furthermore, this estimate is consistent with dolomite–graphite carbon isotope geothermometry, and is considered to be the best estimate of peak metamorphic temperature for this region. Matrix calcite records different stages of retrograde metamorphism and re‐equilibration of calcite that continued until Mg diffusion ceased at ～460 °C. Electron backscattered diffraction (EBSD) results together with morphological features of unmixed coarse tabular dolomite suggest anisotropic diffusion and mineral growth are influenced by crystallographic orientation. Identification of sub‐grain boundaries and formation of fine‐grained unmixing in calcite rims suggest the presence of grain boundary fluids in the late retrograde stages of metamorphic evolution. These results, thus, demonstrate the usefulness of carbonate inclusion geothermometry in estimating the peak metamorphic temperatures of high‐grade terranes and the application of EBSD in understanding the unmixing behaviour of minerals with solid solutions.  相似文献   

长岭断陷火山岩储层内碳酸盐矿物碳氧同位素组成及其成因     

于文修  陆建林  张庆龙  张彦霞  王保华 《矿物岩石地球化学通报》2012,31(1):82-88

碳酸盐矿物是火山岩储层内重要的矿物成分,长岭断陷火山岩储层内的自生碳酸盐矿物主要是方解石.本文通过对营城组储层内方解石矿物的碳氧同位素特征分析,探讨储层内碳酸盐矿物成因.研究表明,长岭断陷火山岩储层内方解石δ13 CV-PDB值范围为-12.7‰～0.4‰,δ18OV-SMOw值范围为3.8‰～12‰,具有高δ18O值.与方解石平衡的CO2碳同位素计算值范围较宽,为-16.0‰～2.2‰,表明其形成物质的多源性.在δ18 O-δ13C图解中显示,形成碳酸盐矿物的CO2来源于幔源-岩浆无机成因的CO2和有机质演化过程中产生的CO2,以无机成因CO2源为主.这些无机成因CO2、有机成因CO2和沉积有机质热演化产生的有机酸溶于流体,形成酸性流体.火山岩储层中碳酸盐矿物的形成实质就是这种酸性流体与储层围岩反应的结果.  相似文献   

雪峰山西侧地区震旦系灯影组碳酸盐岩 储集特征及分布     

李旭兵  刘安  危凯  赵灿 《地质通报》2012,31(11):1872-1877

在对雪峰山西侧地区震旦系灯影组海相地层剖面测量、路线调查及钻井资料分析的基础上,结合灯影组储集岩物性分析数据,阐述了震旦系灯影组的储集岩岩石类型、储集空间、储集性能、储集岩的分布特征及其与沉积环境的关系。认为震旦系灯影组碳酸盐岩储集岩类型主要为鲕粒滩型与白云岩型2类。储集空间类型为溶蚀孔隙、晶间孔隙和裂缝,孔隙连通性较好。灯影组储集层主要分布于慈利-保靖断裂以北的潮坪相区和台缘相区;湖北秭归一带灯影组一段的高能浅滩相鲕粒、砂砾屑白云岩物性最好,孔隙度最大值为11.00％,平均值为8.26％,渗透率最大值为7.72×10-3μm2,平均值为3.66×10-3μm2,属于Ⅱ型储集层。灯影组白云岩储层在中扬子地区多深埋地腹,盖层及保存条件相对较好,是一套分布广泛的储集岩。深入研究震旦系储层对南方海相油气勘探有重要的意义。  相似文献   

贵州省二叠纪岩层崩塌（危岩）发育特征及其诱因分析     

谢兴能  杨胜元  赵国宣  张建江 《贵州地质》2012,29(4):290-294

崩塌（危岩）是贵州地质灾害中主要灾种之一。本文利用重大地质灾害详细调查数据,研究发现贵州广泛分布的二叠系地层中,崩塌主要以倾倒式、规模为小型的地质灾害点为主;碳酸盐岩产生的崩塌众多,而溶蚀裂隙发育的栖霞组一茅口组中崩塌最发育。同时,崩塌点主要分布在贵州西北部及北部;就形成原因而言,作者认为卸荷裂隙与溶蚀裂隙的发育、陡峻的地貌形态、气侯条件和地震等都是造成崩塌发育的关键因子。  相似文献   

塔里木盆地塔中地区上奥陶统储层岩石学及储集空间特征     

徐康  于炳松  刘思彤 《现代地质》2012,26(4):747-754

应用野外工作和室内研究相结合的方法,从储层的岩石学和储集空间等角度对塔中地区储层特征进行了研究。研究表明,研究区内良里塔格组灰岩段岩性主要为颗粒灰岩、骨架礁灰岩、藻粘结灰岩、泥晶灰岩、岩溶角砾岩等,其中颗粒灰岩大多经历了多期多成因成岩作用改造,裂缝较为发育;泥晶灰岩中多期压溶作用和白云石化作用较为常见;藻粘结灰岩受成岩作用改造相对最弱。宏观储集空间主要包括大型溶洞、孔洞及裂缝,其中孔洞多呈孤立、稀疏并沿裂缝分布;构造缝是裂缝的主要类型。微观储集空间主要包括溶孔和微裂缝,其中溶孔主要发育在亮晶颗粒灰岩中,可细分为粒内溶孔、粒间溶孔、晶间溶孔、铸模孔、溶蚀骨架孔、残余粒间孔及沿裂缝扩溶形成的溶孔,粒间溶孔所占比例最高。埋藏期溶蚀作用发育期次多,规模大,分布广泛,对储层物性的改善和油气聚集的影响最为明显。  相似文献   

碳酸盐岩储层测井评价方法     

徐敬领  王亚静  曹光伟  秦宇星 《现代地质》2012,26(6):1265-1274

从碳酸盐岩储层类型划分、储层参数表征、流体性质判别到数学方法的应用等4个方面,系统总结厘定了国内外碳酸盐岩储层测井评价的方法技术,通过对比分析各种评价方法可知:根据一定的数学算法,综合利用常规测井和成像测井不仅能很好地识别储层类型,而且能实现对储层参数的半定量、定量计算评价。利用常规测井和测井新技术资料(电测井和声波测井)计算出缝洞储层的各项物性参数,在此基础上,结合常规测井、核磁共振测井和偶极横波测井能进一步判别出流体性质。通过与岩心分析结果比较,该储层参数计算方法不仅有效,而且简单可行。数学算法和测井新技术资料在复杂碳酸盐岩储层评价中发挥不可替代的作用,能解决复杂碳酸盐岩储层的计算评价问题。以碳酸盐岩储层特征及流体性质为切入点,结合各种地质、地震和测井资料,借助数学算法,准确地识别储层类型与判别流体性质,并精确求解碳酸盐岩储层特别是缝洞储层的物性参数,将是碳酸盐岩储层测井评价的重点及发展方向。  相似文献