Garzón Massif basement tectonics: Structural control on evolution of petroleum systems in upper Magdalena and Putumayo basins,Colombia     

《Marine and Petroleum Geology》2017

The Garzón Massif, is an active Laramide style basement uplift flanked by the Upper Magdalena Valley (UMV) and the Putumayo Basin. In this paper we use new gravity, magnetic, well and seismic data for the first geophysical interpretation of the Garzón Massif. The Garzón/Algeciras fault has been previously interpreted as a right-lateral strike-slip fault. The new seismic, well, and gravity data demonstrates that the Garzón fault is also a low-angle (12–17°) Andean age fault thrusting PreCambrian basement 10–17 km northwestward over Miocene sediments of the UMV in a prospective footwall anticline.The new geophysical data as well as previous field mapping were used to produce the first gravity and magnetic maps and retrodeformable structural cross section of the northern Garzón Massif. The new model distinguishes for the first time distinct episodes of “thin-skinned” and “thick-skinned” deformation in the Garzón Massif. The model indicates approximately 43 km of Early to Middle Miocene shortening by “thin-skinned” imbricate thrusting contemporaneous with the uplift of the nearby southern Central Cordillera (∼9–16 Ma) and the main hydrocarbon expulsion event for the UMV and Putumayo Basin. This was followed by at least 22 km of Late Miocene (3–6 Ma) “thick-skinned” Andean shortening and 7 km of uplift on the symmetrical Garzón thrust and a SE-verging basement thrust fault zone. The Andean uplift interrupted and exposed the hydrocarbon migration pathways to the Putumayo Basin.3-D volume fracture analysis was used for the first time in this paper together with the first seismic and well data published for the Topoyaco and Miraflor structures to test closure models for the Topoyaco foothills. Intense fracturing is observed in the Topoyaco basement monocline from the near-surface to depths of over 3.5 km. The high level of fracturing permitted freshwater flushing and oil biodegradation and hydrocarbon escape. In contrast, the Miraflor-1 well, located just southwest of the Topoyaco block, tested light gravity oil and is sealed from groundwater flushing and biodegradation by a backthrust.  相似文献   

黑龙江佳木斯地块典型石墨矿床含矿岩石地球化学特征及成矿时代          下载免费PDF全文

杨培奇  刘敬党  张艳飞  梁帅  赵越  刘淑梅 《中国地质》2017,44(2):301-315

佳木斯地块位于东北亚早前寒武纪陆块,区内变质岩系发育,是重要的晶质石墨富集地带。文章通过对佳木斯地块典型的萝北云山和鸡西柳毛石墨矿床含矿岩石进行SHRIMP锆石U-Pb年龄测定,结果表明:变质锆石和碎屑锆石207Pb/206Pb年龄分别为(1855±5)~(1979±13)Ma和(476±9)~(575±12)Ma。通过地球化学特征分析,萝北云山石墨矿和鸡西柳毛石墨矿含矿岩石富集Rb、Ba等大离子亲石元素和Zr、Hf、Th、U、Nb、Ta等高场强元素,含矿岩石Rb/Sr平均值均高于陆壳值0.24,表明循环沉积作用较弱;Sr/Ba比值较低,表明岩浆来源于陆壳重熔,显示以陆源物质为主;V/Cr平均值为4.58,V/(Ni+V)平均值为0.90,显示弱还原环境;两处典型矿床轻稀土元素含量均高于重稀土元素,萝北云山矿床负Eu异常明显,显示陆棚浅海沉积特征,鸡西柳毛矿床正Ce异常明显,显示海源物质为主的浅海沉积特征。研究区混合花岗岩脉的稀土元素配分曲线具有正Eu异常,显示出外来岩浆热液交代岩石特征。因此,佳木斯地块典型石墨矿床含矿岩石在古元古代晚期经受区域性高温高压变质作用,后经过早古生代强烈的泛亚构造作用,在构造岩浆侵入背景下进一步增生形成巨晶鳞片状石墨。  相似文献   

西昆仑塔什库尔干地块马尔洋一带中寒武世 花岗岩的发现及地质意义     

李瑞强  贺承广  陈泳霖  姚帅  王坤  李兰兰 《地质力学学报》2019,25(4):590-606

西昆仑塔什库尔干地块马尔洋一带发育一期中寒武世花岗质岩浆活动,岩石类型为片麻状花岗闪长岩和二长花岗岩,LA-ICP-MS锆石U-Pb测年表明,其侵入时代分别为（506.0±6.8）Ma和（514.0±9.3）Ma。岩石SiO₂含量为67.83%~75.76%,具中高钾、准铝质-弱过铝质等特征;岩石稀土总量与平均陆壳相当（∑REE=90.85×10-6~186.10×10-6）,轻、重稀土分馏程度较强（（La/Yb）_N=5.38~22.43）,负Eu异常明显（δEu=0.42~0.71）;微量元素以富集Rb、K、Ba、Th、U等大离子亲石元素和亏损Nb、Ta、P、Ti等高场强元素为特征。地质学及岩石地球化学特征指示该期花岗岩属准铝质到弱过铝质高分异Ⅰ型花岗岩,锆石饱和温度指示其为高温岩浆岩,总体具有壳幔混源的特征,富云包体指示壳源成分占有较大的比例。该期花岗岩与邻区中-晚寒武世中酸性侵入岩指示塔什库尔干-甜水海地块南缘很可能存在一条中寒武世以来的岩浆弧带,其可能为在原特提斯（有限）洋盆于中寒武世向北俯冲、消减背景下幔源物质上涌底侵加热古老陆壳进而发生部分熔融的产物。这也预示着塔什库尔干地区在经过震旦纪-早寒武世伸展裂解阶段之后,于中-晚寒武世其大地构造环境及地球动力学背景发生了重大转折。   相似文献   

松花江地层区古生代地层     

苏养正 《吉林地质》1996,(Z1)

以松花江地块为基础，论述了早寒武纪世上叠盆地局限海沉积、中奥陶世裂陷火山－沉积及晚古生代三个裂陷槽沉积的地层发育特征。  相似文献   

Epigenetic dolomitization of the Přaídolí formation (Upper Silurian), the Barrandian basin,Czech Republic: implications for burial history of Lower Paleozoic strata     

V. Suchý  I. Rozkošný  K. Žák  J. Franců 《International Journal of Earth Sciences》1996,85(2):264-277

Stratabound epigenetic dolomite occurs in carbonate facies of the Barrandian basin (Silurian and Devonian), Czech Republic. The most intense dolomitization is developed in bioclastic calcarenites within the transition between micritic limestone and shaledominated Přídolí and Lochkov formations deposited on a carbonate slope. Medium-crystalline (100–400 μm), inclusion-rich, xenotopic matrix dolomite (δ ¹⁸O=−4.64 to −3.40‰ PDB;δ ¹³C=+1.05 to +1.85‰ PDB) which selectively replaced most of the bioclastic precursor is volumetrically the most important dolomite type. Coarse crystalline saddle dolomite (δ ¹⁸O=−8.04 to −5.14‰ PDB;δ ¹⁸C=+0.49 to +1.49 PDB) which precipitated in fractures and vugs within the matrix dolomite represents a later diagenetic dolomitization event. In some vugs, saddle dolomite coprecipitated with petroleum inclusion-rich authigenic quartz crystals and minor sulfides which, in turn, were post-dated by semisolid asphaltic bitumen. The interpretation of the dolomitization remains equivocal. Massive xenotopic dolomite, although generally characteristic of a deeper burial setting, may have been formed by a recrystallization of an earlier, possibly shallow burial dolomite. Deeper burial recrystallization by reactive basinal pore fluids that presumably migrated through the more permeable upper portion of the Přídolí sequence appears as a viable explanation for this dolomitization overprint. Saddle dolomite cement of the matrix dolomite is interpreted as the last dolomitization event that occurred during deep burial at the depth of the oil window zone. The presence of saddle dolomite, the fluid inclusion composition of associated quartz crystals, and vitrinite paleogeothermometry of adjacent sediments imply diagenetic burial temperatures as high as 160°C. Although high geothermal gradients in the past or the involvement of hydrothermally influenced basinal fluids can account for these elevated temperatures, burial heating beneath approximately 3-km-thick sedimentary overburden of presumably post-Givetian strata, no longer preserved in the basin, appears to be the most likely interpretation. This interpretaion may imply that the magnitude of post-Variscan erosion in the Barrandian area was substantially greater than previously thought.  相似文献   

胶辽地块古元古代大地构造问题：历史观与活动论   总被引：4，自引：0，他引：4  

李三忠 《西北地质》1997,18(3):27-35

对胶辽地块内古元古代活动带的大地构造属性及原始构造线方位、古地理位置，一直存有争议。本文运用历史分析法和活动论的观点，根据大量地质记录提出该活动带经历了裂陷、被动大陆边缘至活动大陆边缘，最后碰撞造山的完整过程，故认为其大地构造属性为一古造山带；通过消除中新生代郯庐断裂左行错移等后期地质事件的影响，可以认为该古造山带的原始构造线方位应为EW走向，其古地理位置应与现今华北地块南缘对比。  相似文献   

贵东岩体花岗岩的成因类型及成矿专属性探讨   总被引：10，自引：1，他引：10  

张成江 《铀矿地质》1991,7(4):223-234

  相似文献   

两种不同类型花岗绿岩地体的金矿化差异     

陈衍景  富士谷 《华东地质学院学报》1992,15(1):23-30

  相似文献   

论大别地块中榴辉岩与围岩的变质关系及区域“递增”变质带的形成     

刘晓春  刘先文  胡克 《吉林大学学报(地球科学版)》1992,(4)

研究表明,大别地块中榴辉岩形成时的变质压力从东南向西北呈递减趋势,由2.8～3.5GPa降至约1.0GPa,而温度变化则不明显,由647～755℃略增至684～829℃.榴辉岩的围岩中某些残留高压矿物或其假象的发现证明它们与榴辉岩一起经历了原地高压变质作用过程.不同地区榴辉岩的退变组合及P—T条件与围岩同步变化,从绿帘角闪岩相、角闪岩相到麻粒岩相,从而表明现今围岩所展示出的“递增”变质带是由榴辉岩相退变质作用造成的,其形成时代可能不早于晚元古代.  相似文献   

Fluorite Deposits at Voznesenka in the Khanka Massif, Russia: Geology and Age of Mineralization   总被引：1，自引：0，他引：1  

Kohei Sato  Kazuhiro Suzuki  Munetomo Nedachi    Shigeru Terashima    Margarita D. Ryazantseva    Anatoly A. Vrublevsky  + Alexander I. Khanchuk  ++ 《Resource Geology》2003,53(3):193-211

Abstract. A huge fluorite deposit at Voznesenka in the Khanka massif, Far East Russia is concluded to have formed at ca. 450 Ma in Late Ordovician time based on the K‐Ar ages for Li‐micas in the fluorite ore and greisenized leucogranite within the deposit. This conclusion is inconsistent with the current view of Devonian mineralization that stemmed from widely scattered whole‐rock Rb‐Sr isotope data for the heterogeneous leucogranite stocks influenced by strong alteration. The Voznesenka and neighboring fluorite deposits may have formed in Cambrian limestone in relation to the intrusion of the Li‐F‐rich felsic magma which has a similar chemistry to representative Li‐F‐rich felsic rocks including topaz granite and ongonite or topaz rhyolite; these rocks may be classified as a specific group of highly fractionated felsic magmas. Biotite granite plutons exposed in the Voznesenka district are divided in age into two groups based on the CHIME age data for zircon, monazite and xenotime: Ordovician and Permian. The Ordovician plutons seem to be coeval to the fluorite deposits and are characterized by F‐rich chemistry, reduced nature and association of tin mineralization with the deposition of fluorite and tourmaline. The biotite granite magmas of initially enhanced F contents could have been highly fractionated to form Li‐F‐rich leucogranite cupolas that provided fluorite deposits within the host limestone. Future prospecting for similar fluorite deposits is to be focused on areas of intersection between Ordovician Li‐F‐rich granite and Cambrian carbonate sequences. The Permian granite of southeastern margin of the Grodekovo batholith is characterized by lesser F content, oxidized nature and the lack of tin and fluorite mineralization in contrast to the Ordovician granite. The result of Permian age does not support the current view of Silurian age for the batholith and requires overall chronological reinvestigation in connection with the tectonic history of the Khanka massif because the Grodekovo is a representative of Paleozoic batholiths in Primorie.  相似文献