四川盆地泸州古隆起嘉陵江组储层特征研究   总被引：1，自引：0，他引：1  

朱其  李国蓉  乔占峰  王鑫  许维武 《四川地质学报》2008,28(1):30-34

对研究区嘉陵江组沉积背景认识的基础上,通过岩心观察、岩石薄片确定了不同类型的储集岩和储集空间,得出本地区储层岩石类型和储渗空间类型均多样化的特点。从成因角度识别出来了溶蚀孔隙型储层、膏溶孔洞型储层、裂缝型储层等三类储层。研究不同类型储层的孔、渗特征及关系表明,溶蚀孔隙型储层物性要优于膏溶孔洞型储层,而溶蚀孔隙型储层中的颗粒云岩溶蚀孔隙型储层物性最好、颗粒灰岩溶蚀孔隙型物性其次、粉晶云岩溶蚀孔隙型储层物性最差,其原因是不同储层受沉积环境和成岩作用控制和影响。  相似文献   

First finds of Late Tithonian and middle-late Albian radiolarian assemblages in volcanogenic-siliceous rocks of the Amur River right lower reaches and their tectonic significance     

A. N. Filippov  I. V. Kemkin 《Russian Journal of Pacific Geology》2008,2(5):412-421

The lithological-stratigraphic study of volcanogenic-siliceous rocks developed on the left side of the Machtovaya River, a right tributary of the Amur River, yielded the first radiolarian assemblages of the late Late Tithonian, the late Late Tithonian-early Valanginian, and the middle-late Albian age. It is established that the stratigraphic succession of volcanogenic-siliceous rocks in this area is composed of upper Tithonian-Valanginian dark red to red-brown cherts with basalts in the lower part of the section and Albian dark gray clayey cherts, olive-gray siliceous-tuffaceous argillites, and tufaceous siltstones in its upper part. The replacement of cherts by their clayey varieties likely occurred in the Aptian. The composition, structure, and age of these strata and the rocks constituting the Kiselevka-Manoma accretionary complex are different, which indicates their different tectonic origin.  相似文献   

(ϖμ/ϖT) P of the lower mantle     

Yanbin Wang  Donald J. Weidner 《Pure and Applied Geophysics》1996,146(3-4):533-549

We estimate (/T) _P of the lower mantle at seismic frequencies using two distinct approaches by combining ambient laboratory measurements on lower mantle minerals with seismic data. In the first approach, an upper bound is estimated for |(/T) _P | by comparing the shear modulus () profile of PREM with laboratory room-temperature data of extrapolated to high pressures. The second approach employs a seismic tomography constraint ( lnV _S / lnV _P ) _P =1.8–2, which directly relates (/T) _P with (K _S /T) _P . An average (K _S /T) _P can be obtained by comparing the well-established room-temperature compression data for lower mantle minerals with theK _S profile of PREM along several possible adiabats. Both (K _S /T) and (/T) depend on silicon content [or (Mg+Fe)/Sil of the model. For various compositions, the two approaches predict rather distinct (/T) _P vs. (K _S /T) _P curves, which intersect at a composition similar to pyrolite with (/T) _P =–0.02 to –0.035 and (K _S /T) _P =–0.015 to –0.020 GPa/K. The pure perovskite model, on the other hand, yields grossly inconsistent results using the two approaches. We conclude that both vertical and lateral variations in seismic velocities are consistent with variation due to pressure, temperature, and phase transformations of a uniform composition. Additional physical properties of a pyrolite lower mantle are further predicted. Lateral temperature variations are predicted to be about 100–250 K, and the ratio of ( lnp/ lnV _S ) _P around 0.13 and 0.26. All of these parameters increase slightly with depth if the ratio of ( lnV _S / lnV _P ) _P remains constant throughout the lower mantle. These predicted values are in excellent agreement with geodynamic analyses, in which the ratios ( ln / lnV _S ) _P and ( / lnV _S ) _P are free parameters arbitrarily adjusted to fit the tomography and geoid data.  相似文献   

赣东北鹅湖岭组的再认识   总被引：9，自引：2，他引：7  

巫建华 《地层学杂志》1996,20(2):153-160

在分析赣东北鹅湖岭组及有关地层的地质特征、地层划分现状及产生分岐的原因的基础上,提出以岩性、岩相为划分依据,将鹅湖岭组与喷发相相对应,将其下界、上界分别置于沉积喷发相与喷发相、喷发相与喷发沉积相的相变界面上。从而将北京地质学院指定的打鼓顶组建组剖面上的"打鼓顶组"并入鹅湖岭组;将赣东北其它地区的鹅湖岭组下界由安山岩层顶界处上移至安山岩层之上灰绿色砂岩层的顶界处,将铅山一上饶一带鹅湖岭组上界下移至原鹅湖岭组上部的底界处。  相似文献   

东秦岭中部奥陶系-志留系界线地层及腕足动物群   总被引：1，自引：0，他引：1  

许汉奎 《地层学杂志》1996,20(3):165-174

东秦岭中部晚奥陶世和早志留世地层分布较广,化石较丰富,尤其是腕足类,分为寺岗组、石燕河组、刘家坡组和张湾组。曾庆銮等(1993)根据腕足类及其群落的更替,把石燕河组和刘家坡组归於早志留世,因而引起较大争论。本文据岩性将寺岗组和石燕河组分别改称为石燕河组下段和上段,并据腕足类化石认为石燕河组和刘家坡组应归於晚奥陶世、张湾组为早志留世;另据上述地层生物群落的特征及群落的更替,认为从石燕河组到刘家坡组,以及刘家坡组至张湾组恰好反映了全球冰期引起的晚奥陶世海退和早志留世冰期结束引起的海侵,故本区奥陶系-志留系界线宜划在刘家坡组和张湾组之间。  相似文献   

Provenance of Conglomerate and Sandstone from Early Permian Shoushangou Formation in Xi Ujimqin, Inner Mongolia: Implications for Understanding Paleo-Asian Ocean Subduction     

ZHANG Yingli  GUO Xianqing  MA Shouxian 《《地质学报》英文版》2024,98(1):10-31

During the Late Carboniferous to Early Permian, a rift was formed by post-collisional extension after ocean closure or an island arc-related basin formed by Paleo-Asian Ocean (PAO) subduction in the Xi Ujimqin area. Nevertheless, the closure time of the PAO is still under debate. Thus, to identify the origin of the PAO, the geochemistry and U-Pb age of zircons were analyzed for the extra-large deep marine, polymict clastic boulders and sandstones in the Shoushangou Formation within the basin. The analyses revealed magmatic activity and tectonic evolution. The conglomerates include megaclasts of granite (298.8 ± 9.1?Ma) and granodiorite porphyry (297.1 ± 3.1?Ma), which were deposited by muddy debris flow. Results of this study demonstrated that the boulders of granitoids have the geochemistry of typical I-type granite, characterized by low Zr + Nb + Ce + Y and low Ga/Al values. The granitoid boulders were formed in island arc setting, indicating the presence of arc magmatism in the area that is composed of the Late Carboniferous to Early Permian subduction-related granitoid in southern Xi Ujimqin. Multiple diagrams for determining sedimentary provenance using major and trace elements indicate that Shoushangou sediments originated from continental island arc-related felsic rocks. Detrital zircon U-Pb age cluster of 330–280?Ma was obtained, indicating input from granite, ophiolite, Xilin Gol complex, and Carboniferous sources to the south. The basin was geographically developed behind the arc during the Early Permian period because the outcropped intrusive rocks in the Late Carboniferous to Early Permian form a volcanic arc. The comprehensive analyses of source areas suggest that Shoushangou sediments developed in a backarc basin in response to the northward subduction of the PAO. The backarc basin and intrusive rocks, in addition to previously published Late Carboniferous to Early Permian magmatic rocks of arc unit in Xilin Gol, confirm the presence of an Early Permian trench-arc-basin system in the region, represented by the Baolidao arc and Xi Ujimqin backarc basin. This study highlights the importance and potential of combined geochemical and geochronological studies of conglomerates and sandstone for reconstructing the geodynamic setting of a basin.  相似文献   

河北宣化土城子组恐龙足迹化石新发现     

鞠书彬  王旭日  董颖  刘义川  季燕南  季强 《地质学报》2022,96(7):2295-2311

本文报道了新近发现于河北宣化地区土城子组的恐龙足迹化石及沉积环境。为确定足迹化石的地质年代、土城子组的沉积环境及足迹化石属种，本文在对恐龙足迹化石层及其上、下地层进行剖面测制、沉积相划分和沉积环境分析的基础上，对化石层上覆凝灰岩层进行了LA- ICPMS锆石U- Pb测年，并对保存较好的足迹化石进行了测量和对比研究工作。研究结果表明，土城子组底部为冲积扇扇中沉积环境，足迹化石上、下地层则表现为河流相沉积环境，而足迹化石的赋存层位形成于滨湖相沉积环境，发育暴露构造并含有大量裸子植物碎屑化石。凝灰岩锆石U- Pb加权平均年龄为152. 3±0. 3 Ma（MSWD=0. 00106），说明化石层位于土城子组一段，时代属于晚侏罗世钦莫利期（Kimmeridgian）中晚期。已发现的足迹化石以兽脚类三趾型足迹为主，包括跷脚龙足迹属（Grallator）、安琪龙足迹属（Anchisauripus）和实雷龙足迹属（Eubrontes），其次为一些疑似蜥脚类恐龙足迹，是华北北缘土城子组中群落丰富度最高的恐龙足迹点，其中一处或许为中国北方面积最大的恐龙足迹点。因此，我们认为宣化- 下花园盆地土城子组一段以河流、湖泊相沉积环境为主，当时裸子植物繁茂，恐龙动物群庞大，偶尔存在火山喷发活动。新发现的宣化恐龙足迹不仅填补了宣化- 下花园地区恐龙足迹化石的空白，也丰富了燕辽地区土城子组生物群的组合面貌，为土城子组内年代地层划分及陆相J/K界线的确定提供了新的证据。  相似文献   

张广才岭南部杨木岗组的厘定及物源分析     

任永健  张成信  孟庆伟 《地质学报》2022,96(7):2333-2347

本文通过岩石组合特征和区域对比，将张广才岭南部西蛤拉河子—大锅盔一带分布的浅变质地层重新厘定为杨木岗组。为了确定杨木岗组的形成时代和沉积物源，进行了碎屑锆石U- Pb年代学和微体古生物地层学研究。锆石大多数呈自形—半自形晶，显示典型振荡岩浆生长环带，暗示其岩浆成因。该地层中测得的两组碎屑锆石U- Pb产生多组谐和年龄，其中PM010- TW样品56个测点最小峰值(谐和)年龄为307 Ma，DB02- TW样品51个测点最小峰值(谐和)年龄为275 Ma；覆盖在杨木岗组之上的中生代二浪河组安山岩的定年结果为181. 1±0. 9 Ma，表明杨木岗组形成于早二叠世晚期。杨木岗组中获取疑源类化石组合出现了新元古代晚期—早寒武世和奥陶纪地层常见分子，结合碎屑锆石年龄结果，反映杨木岗组沉积时周围存在早古生代和中—新元古代地质体。碎屑沉积岩Al2O3/TiO2平均值为24. 44，稀土元素球粒陨石标准化曲线具有轻稀土富集、重稀土稳定和负Eu异常特征，结合碎屑锆石的年龄频数可以看出，确定杨木岗组的沉积物主要来源于沉积盆地周围的晚古生代早期中酸性火成岩，次要物源由沉积盆地周边的早古生代地质体和近地表的中—新元古代地质体提供。佳木斯地块为松嫩- 张广才岭地块上晚古生代地层的形成提供了部分物源，暗示佳木斯地块与松嫩- 张广才岭地块于早二叠世之前已完成拼合。  相似文献   

含煤层地质环境下地震波场的数值模拟   总被引：3，自引：2，他引：1  

潘冬明  杨顶辉 《地球物理学进展》1997,12(1):74-83

本文对含低速煤层地质环境下弹性波场多波多分量地震资料进行了二维数值模拟研究,对人工边界反射进行了有效处理,频散效应得到了有效的压制,对几种不同激发与观测排列方式下的弹性波资料进行了模型计算与分析。  相似文献   

洛安江干渠老菁湾滑坡分析     

周华志 《工程地质学报》1995,3(1):86-91

洛安江水库灌溉工程是贵州黔北万亩以上骨干工程之一,中华人民共和国成立初期建成。１９９１年＂７．５Ｆ＂洪灾,连续大暴雨,河水暴涨,倒灌暗河,产生高静、动水压力作用。岸坡岩体受不利结构面组合,发生顺层岩质滑坡,破坏干渠,严重影响灌溉。本文根据滑坡破坏情况,对滑坡产生的地质环境、滑坡特征、滑坡形成机理（滑坡形式和破坏机理,各种稳定性分析与评价）,以及产生滑坡原因进行了初步分析。  相似文献