渝东南下志留统龙马溪组页岩储集层成岩作用及其对孔隙发育的影响^*          下载免费PDF全文

赵迪斐  郭英海  杨玉娟  王守玉  毛潇潇  李咪 《古地理学报》2016,18(5):843-856

以重庆綦江、南川和涪陵地区的下志留统龙马溪组下部页岩样品为例,通过X射线衍射(XRD)、场发射扫描电镜、TOC测试、R_O测试、高压压汞和低温氮吸附等手段,对研究区龙马溪组下部页岩储集层的矿物成分、有机组分、孔隙特征及成岩作用进行研究。实验结果表明,龙马溪组页岩成岩作用类型主要包括机械压实作用、化学压实作用、溶蚀作用、交代作用、破裂作用及矿物转化等,演化阶段介于晚成岩作用与极低级变质作用之间;成岩作用对页岩储集层的孔渗特征、孔隙成因类型、非均质性和形貌特征均有显著影响。对成岩作用与孔隙演化进行了匹配,认为机械/化学压实作用、溶蚀作用及过程中的有机生烃、矿物转化对孔隙发育影响最为显著,并将储集层成岩作用划分为溶蚀作用等建设性成岩作用与压实作用等破坏性成岩作用。  相似文献   

滇东北矿集区昭通铅锌矿区蚀变岩分带及元素迁移特征   总被引：1，自引：0，他引：1  

陈随海  韩润生  申屠良义  吴鹏  邱文龙  文德潇 《吉林大学学报(地球科学版)》2016,46(3):711-721

围岩蚀变是昭通铅锌矿床的重要找矿标志。通过对矿区760中段98勘探线剖面实测、蚀变岩分带研究、岩石地球化学迁移特征与参数计算,指出围岩蚀变与成矿的关系：热液蚀变分带明显,在蚀变中心,黄铁矿化最强,方解石化、白云石化次之,硅化较弱,黄铁矿化与矿化关系密切;远离矿体,黄铁矿化逐渐减弱,而方解石化、白云石化逐渐增强。强黄铁矿化和强黄铁矿化-强方解石化-强硅化粗晶白云岩蚀变组合是重要的找矿标志。从细晶白云岩带到强黄铁矿化带,元素整体呈迁入形式,主要为与Zn-Pb成矿作用有关的元素,如Ge、Ag、Cd等迁入;同时伴随成矿流体作用,亲铁元素及铁明显富集,显示不同蚀变岩相受热液改造作用影响。蚀变指数（I_A）的大小,与矿化强弱呈正相关关系,I_A大,则矿化强。  相似文献   

重庆秀山小茶园锰矿南华系大塘坡组古环境^*          下载免费PDF全文

马志鑫  罗亮  刘喜停  刘伟  孙志明 《古地理学报》2016,18(3):473-486

认识渝湘黔地区南华系的沉积构造背景可以为该地区锰矿勘探提供新的依据,基于此,文中对重庆秀山小茶园锰矿ZK0606钻孔的南华系千子门组和大塘坡组开展了系统的沉积环境和地球化学分析。沉积相分析结果表明,该套地层共可划分出冰水浅海、局限边缘盆地和浅水陆棚3种沉积环境。地球化学分析结果表明,研究区大塘坡组稀土元素总量较高、富轻稀土元素、具Eu负异常,结合Al₂O₃/(Al₂O₃+Fe₂O₃)、Al/(Al+Fe+Mn)值等,推测其形成于被动大陆边缘背景。根据微量元素含量及其比值(U、V、Mo、V/Cr)等推测,大塘坡组一段沉积于缺氧—贫氧沉积环境,而大塘坡组二段逐渐过渡到氧化沉积环境;根据Al/Ca值、化学蚀变指数(CIA)等指标分析,该套地层自下而上化学风化强度逐渐增大、陆源碎屑供给增多,这可能与Sturtian冰期结束、气候变暖和海平面迅速升高有关。综合上述分析结果认为,重庆秀山小茶园锰矿主要产出于大塘坡组一段下部相对深水厌氧的局限边缘盆地环境中。  相似文献   

Simulating net primary production of grasslands in northeastern Asia using MODIS data from 2000 to 2005     

XING Xiaoxu  XU Xingliang  ZHANG Xianzhou  ZHOU Caiping  SONG Minghua  SHAO Bin  OUYANG Hua 《地理学报》2010,20(2):193-204

The net primary production (NPP) of grasslands in northeastern Asia was estimated using improved CASA model with MODIS data distributed from 2000 and ground data as driving variables from 2000 to 2005. Average annual NPP was 146.05 g C m?2 yr?1 and average annual total NPP was 0.32 Pg C yr?1 in all grasslands during the period. It was shown that average annual grassland NPP in the whole northeastern Asia changed dramatically from 2000 to 2005, with the highest value of 174.80 g C m?2 yr?1 in 2005 and the lowest value of 125.65 g C m?2 yr?1 in 2001. On regional scale, average annual grassland NPP of 179.71 g C m?2 yr?1 in southeastern Russia was the highest among the three main grassland regions in the six years. Grasslands in northern China exhibited the highest average annual total NPP of 0.16 Pg C yr?1 and contributed 51.42% of the average annual total grassland NPP in northeastern Asia. Grassland NPP in northeastern Asia also showed a clear seasonal pattern with the highest NPP occurred in July every year. Average monthly grassland NPP in southeastern Russia was the highest from May to August while average monthly grassland NPP in northern China showed the highest NPP before May and after August. The change rate distribution of grassland NPP between the former three years and the latter three years showed grassland NPP changed slightly between the two stages in most regions, and that NPP change rate in 80.98% of northeastern Asia grasslands was between –0.2 and 0.2. Grassland NPP had close correlation with precipitation and temperature, that indicates climate change will influence the grassland NPP and thus have a great impact on domestic livestock in this region in future.  相似文献   

Deposition and erosion in the fluctuating backwater reach of the Three Gorges Project after upstream reservoir adjustment   总被引：1，自引：1，他引：0  

Yongjun LU Liqin ZUO Rongyao JI Huaixiang LIU 《国际泥沙研究》2010,25(1):64-80

The construction of hydropower projects,such as Xiluodu and Xiangjiaba Reservoirs,in the upper Yangtze River will lead to variations of the incoming water and sediment conditions and in turn changes in the deposition and erosion processes in the fluctuating backwater reach of the Three Gorges Project(TGP).In this paper,based on the water and sediment characteristics,a 2D mathematical model in the boundary-fitting orthogonal curvilinear coordinate system has been employed to predict the space-time changes of...  相似文献   

重庆地区地震统计单元b值和ν_4值的讨论     

秦娟  李光  王宏超 《四川地震》2010,(1)

b值和ν4是地震安全性评价工作中进行地震危险性概率计算的两个重要参数,其取值是否合理将影响地震危险性计算结果的合理性.本文采取两种不同的计算方法对重庆地区的b值和ν4进行计算,并对于这两个参数进行了讨论.我们认为取 b=1.19和ν4=2.48基本上是合理的,该结果对重庆地区开展地震安全性评价工作和地震中长期预报工作具有一定的参考价值.  相似文献   

努力培养地震监测全方位人才     

余国政  王小龙  李强  郭欣 《高原地震》2010,22(1):65-68

介绍了重庆市地震局三峡水库地震监测中心根据人少、事多、经验不足和人员年轻的实际情况,正确引导,制定出分工合作、各有侧重的工作方针;创造以人为本,科学发展的有利于学习、工作和锻炼的良好环境。通过实践锻炼,年轻职工成长为技术上一专多能、管理上能操控各种复杂局面的地震监测全方位人才。  相似文献   

Geographical distribution of helium isotope ratios in northeastern Japan   总被引：1，自引：0，他引：1  

Keika  Horiguchi  Sadato  Ueki  Yuji  Sano  Naoto  Takahata  Akira  Hasegawa  George  Igarashi 《Island Arc》2010,19(1):60-70

In order to study the precise geographical distribution of helium isotope ratios in northeastern Japan and compare it with geophysical data, we collected 43 gas and water samples from hot and mineral springs in the region where the ratio had never been reported, and measured the ³He/⁴He and ⁴He/²⁰Ne ratios of these samples. It was found that the ³He/⁴He ratios show clear contrasts between the forearc and the back-arc regions in the Tohoku district in northeastern Japan. In the forearc region, the ratios are smaller than 1 R_A (1 R_A = 1.4 × 10⁻⁶; R_A means the ³He/⁴He ratio of the atmosphere). On the other hand, those along the volcanic front and in the back-arc region are apparently higher. Moreover, we found a variation in the ³He/⁴He ratios along the volcanic front. In Miyagi Prefecture (38–39°N), the ratios range from 2 to 5 R_A. On the other hand, the ratios are less than 1 R_A in and around the southern border between Iwate and Akita Prefectures (39–39.5°N). Comparing the distribution of helium isotope ratios to results of recent geophysical studies, we found that the features in geographical distribution of helium isotope ratios are similar to those of seismic low-velocity zone distributions and high Qp⁻¹ distributions in the uppermost mantle. These observations strongly suggest that the helium isotope ratios reflect the distribution of melts in the uppermost mantle and are a useful tool for investigating the origin, behavior, and distribution of deep fluids and melts.  相似文献   

山地城镇土地利用的经济生态位分析及持续发展--以重庆市为例   总被引：8，自引：0，他引：8  

秦建成  高明 《山地学报》2003,21(6):702-706

土地利用变化已成为当今经济社会中最活跃和最普遍的现象,是土地利用类型从低生态位向高生态位转变的自组织行为。对不同层次土地利用经济生态位进行调控,才能实现土地的持续利用。本文在生态位理论和系统边界理论的基础上,运用土地利用经济生态位模型,定量分析了重庆市土地利用类型间相互作用的强度。研究表明,重庆市农用地与非农用地经济生态位差较大,经济发展和城市化进程更加剧了建设用地占用农用地的速度和强度。同时,从经济生态位的角度探讨了持续土地利用的方法。  相似文献   

川东北地区上二叠统长兴组生物礁组成及成礁模式   总被引：47，自引：2，他引：45       下载免费PDF全文

牟传龙  谭钦银  余谦  王立全  王瑞华 《沉积与特提斯地质》2004,24(3):65-71

川东北地区在地表露头上目前发现的长兴组生物礁以盘龙洞、通江铁厂河和羊鼓洞生物礁为代表。野外和室内综合研究表明：盘龙洞生物礁发育完好,生长有大量骨架岩,而羊鼓洞生物礁骨架岩几乎不发育,以障积岩为主夹少量粘结岩;盘龙洞骨架间充填物为生物碎屑和砂屑为主,泥晶灰泥很少,而羊鼓洞以生物碎屑和方解石灰泥为主;盘龙洞生物礁普遍发生了白云岩化,而羊鼓洞白云岩化极其微弱。通过盘龙洞与羊鼓洞生物礁对比研究,认为两者非同时形成,羊鼓洞生物礁早于盘龙洞,生物礁有由台地向盆地迁移趋势,其成礁模式为台地边缘礁滩组合型缓坡模式。  相似文献