塔里木盆地古隆1井中上奥陶统牙形石生物地层界线研究   总被引：1，自引：0，他引：1       下载免费PDF全文

蔡习尧  祁玉平  钱一雄  陈跃 《地质科学》2011,46(2):466-474

塔中地区古隆1井中晚奥陶世处于台缘斜坡带,地层发育齐全,奥陶系划分为3统5组,自上而下为却尔却克组、恰尔巴克组、一间房组、鹰山组与蓬莱坝组.在恰尔巴克组及一间房组分别获得了Pygouds anserinus与P.serra牙形石带,依此将中上奥陶统界线划在5875 m,两统之间不存在任何地层缺失或不整合面.认为碳酸盐岩...  相似文献   

Carbon isotope composition of Upper Cambrian to Lower Ordovician carbonate in Korea,and its bearing on the Cambrian–Ordovician boundary and Lower Ordovician paleoceanography     

Sung Kyung Hong  Yong Il Lee  So Yeong Jeong 《Journal of Asian Earth Sciences》2011,40(1):252-260

This study presents an example of locating Cambrian–Ordovician boundary in the lower Paleozoic carbonate succession in Korea using carbon isotope stratigraphy. The Yeongweol Unit of the lower Paleozoic Joseon Supergroup comprises the Upper Cambrian Wagok Formation and the Lower Ordovician Mungok Formation in the Cambrian–Ordovician transition interval. Conventionally, the boundary was placed at the lithostratigraphic boundary between the two formations. This study reveals that the boundary is positioned in the basal part of the Mungok Formation based on the carbon isotope stratigraphy coupled with biostratigraphic information of conodont and trilobite faunas. The δ¹³C curve of the Lower Ordovician Mungok Formation shows a similar trend to that of the coeval stratigraphic interval of Argentine Precordillera (Buggisch et al., 2003), suggesting that the δ¹³C curve of the Mungok Formation reflects the Early Ordovician global carbon cycle.  相似文献   

Relationships among volcanic and hydrothermal activity and faults from the Shunnan 3-D well zone in the Tadong Area (Tarim Basin,China)     

Li KunBai  Lv HaiTao  Pu RenHai  Cao ZiCheng 《Arabian Journal of Geosciences》2016,9(17):692

Tarim Basin distributed widely two stages of Permian volcanic rocks. However, the location and timing of these rocks pinching out and the relationship between Ordovician carbonate hydrothermal reservoirs and fault activity remain unclear. The Shunnan (Shunnan here in after referred to as SN) 1 3-D well zone in the eastern Tarim Basin contains volcanic rocks, and the Ordovician layer contains a hydrothermal reservoir. This paper describes the lithology, stage, volcanic rock distribution, crater position and deposition pinch-out line of volcanic rocks based on drilling and 3-D seismic data. The Permian strata in the well zone contain only one stage of Kupkuciman Formation basalt and tuff, the Kaipeleicike Formation contains terrigenous clastic rock and the adjacent volcanic rocks of wells SN2 and GL (Gulong here in after referred to as GL) 2 exhibit an absence of deposition. Although the craters are distributed on both sides of the NNW faults that cross well SN4, their positions are also controlled by the intersection of earlier NEE and NW faults and later NNE faults. Furthermore, the Ordovician strata in the SN1 well zone developed abundant tubular high-amplitude anomalies and tabular high-amplitude anomalies via hydrothermal corrosion, and the anomaly distributions are similar to the positions of the craters, which are controlled by the intersection of multi-group faults and the density of the faults.  相似文献   

塔里木盆地麦盖提斜坡奥陶纪地层划分对比及意义     

刘忠宝  张福顺  高山林  岳勇 《世界地质》2016,35(3):708-716

以碳同位素值的波动变化与沉积环境、海平面升降及地层界面突变等地质事件相对应为理论依据,开展碳同位素地层研究,建立了各组值域划分标准,解决碳酸盐岩地层缺乏标准生物化石情况下,地层归属难确定的问题。指出奥陶系自下而上碳同位素曲线呈现稳定-上升-正漂移的过程。其中,下统蓬莱坝组—鹰山组δ~(13)C值范围为(-4.2~-0.2)×10~(-3),始终为负值;中统一间房组δ~(13)C值范围为(-0.4~0.6)×10~(-3),以分布在零值附近为特征;上统恰尔巴克组—良里塔格组δ~(13)C值范围(0.7~3.1)×10~(-3),均为正值。在此基础上,开展了巴楚典型露头剖面与麦盖提斜坡井下奥陶系碳同位素地层与岩石地层对比研究,提出麦盖提斜坡中部及东部断洼区发育上奥陶统,除东部断裂带外,普遍残存下奥陶统顶部泥晶灰岩段。  相似文献   

Chemostratigraphy of Paleoproterozoic carbonate successions of the Wyoming Craton: tectonic forcing of biogeochemical change?     

A. Bekker  J. A. Karhu  K. A. Eriksson  A. J. Kaufman 《Precambrian Research》2003,120(3-4):279-325

The Archean Wyoming Craton is flanked on the south and east by belts of Paleoproterozoic supracrustal successions whose correlation is complicated by lack of geochronologic constraints and continuous outcrop. However, carbonate units in these successions may be correlated by integrating carbon isotope stratigraphy with lithostratigraphy. The 10 km thick Paleoproterozoic Snowy Pass Supergroup in the Medicine Bow Mountains was deposited on the present-day southern flank of the Wyoming Craton; it contains three discrete levels of glacial diamictite correlative with those in the Huronian Supergroup, on the southern margin of the Superior Craton. The Nash Fork Formation of the upper Snowy Pass Supergroup is significantly younger than the uppermost diamictite and was deposited after the end of the Paleoproterozoic glacial epoch. Carbonates at the base of the Nash Fork Formation record remarkable ¹³C-enrichment, up to +28‰ (V-PDB), whereas those from overlying members of the lower Nash Fork Formation have δ¹³C values between +6 and +8‰. Carbonates from the upper Nash Fork Formation above the carbonaceous shale have carbon isotope values ranging between 0 and +2.5‰. The transition from high carbon isotope values to those near 0‰ in the Nash Fork Formation is similar to that at the end of the ca. 2.2–2.1 Ga carbon isotope excursion in Fennoscandia. This chemostratigraphic trend and deposition of BIFs, Mn-rich lithologies, carbonaceous shales and phosphorites at the end of the global ca. 2.2–2.1 Ga carbon isotope excursion are likely related to ocean overturn associated with the final breakup of the Kenorland supercontinent. Correlative carbonates from the Slaughterhouse Formation in the Sierra Madre, WY, and from the Whalen Group in the Rawhide Creek area in the Hartville Uplift, WY, have highly positive carbon isotope values. In contrast, carbonates from other exposures of the Whalen Group in the Hartville Uplift and all carbonate units in the Black Hills, SD, have carbon isotope values close to 0‰. Combined with existing geochronologic and stratigraphic constraints, these data suggest that the Slaughterhouse Formation and the succession exposed in the Rawhide Creek area of the Hartville Uplift are correlative with the lower and middle Nash Fork Formation and were deposited during the ca. 2.2–2.1 Ga carbon isotope excursion. The Estes and Roberts Draw formations in the Black Hills and carbonates from other exposures in the Hartville Uplift postdate the ca. 2.2–2.1 Ga positive carbon isotope excursion and are most likely correlative with the upper Nash Fork Formation. The passive margin, on which the carbonates with highly positive carbon isotope values were deposited, extended around the southern flank of the Wyoming Craton through the Sierra Madre, Medicine Bow Mountains and Hartville Uplift. The presence of carbonates with carbon isotope values close to 0‰ in the upper Nash Fork Formation and the Whalen Group indicates that the passive margin persisted on the southern flank of the Wyoming Craton after the carbon isotope excursion. Rifting in the Black Hills, likely related to the final breakup of the Kenorland, succeeded the carbon isotope excursion, since the Estes and Roberts Draw formations, deposited during rifting and ocean opening on the eastern flank of the Wyoming Craton, postdate the carbon isotope excursion.  相似文献   

新疆巴楚中—晚奥陶世牙形刺生物地层和沉积环境研究   总被引：2，自引：0，他引：2  

李越  黄智斌  王建坡  王志浩  薛耀松  张俊明  张元动  樊隽轩  张园园 《地层学杂志》2009,33(2)

塔里木盆地中央隆起区的中—上奥陶统灰岩相地层露头分布在巴楚良里塔格地区的一间房—唐王城。以牙形刺动物群为依据厘定3个组的时代,从下至上为一间房组(Periodus flabellum层、Pygodus serra层,属达瑞威尔阶)、吐木休克组(Pygodus anserinus层、Baltoniodus alobatus带,属桑比阶)和良里塔格组(含B.confluens动物群层,属凯迪阶下部)。一间房组的开始标志了新一期的海进,此组下段发育1期藻丘,中段发育1期藻丘、1期瓶筐石礁丘和3—4期瓶筐石—棘屑滩,上段代表了海水加深至浪基面之下的过程;吐木休克组沉积过程中达到了海进最大值,为凝缩沉积;良里塔格组代表了逐渐海退的过程,由浅滩和3期藻丘建造组成。  相似文献   

Stable carbon‐isotope record of shallow‐marine evaporative epicratonic basin carbonates,Ordovician Williston Basin,North America          下载免费PDF全文

Antun Husinec  Stig M. Bergström 《Sedimentology》2015,62(1):314-349

Secular variations in stable carbon‐isotope values of marine carbonates are used widely to correlate successions that lack high‐resolution index fossils. Various environmental processes, however, commonly may affect and alter the primary marine carbon‐isotope signal in shallow epicratonic basins. This study focuses on the marine carbon‐isotope record from the carbonate–evaporite succession of the upper Katian (Upper Ordovician) Red River Formation of the shallow epicratonic Williston Basin, USA. It documents the carbon‐isotope signal between the two major Ordovician positive shifts in δ¹³C, the early Katian Guttenberg and the Hirnantian excursions. Eight δ¹³C stages are identified based on positive excursions, shifts from positive to negative values and relatively uniform δ¹³C_carb values. A correlation between carbon‐isotope trends and the relative sea‐level changes based on gross facies stacking patterns shows no clear relation. Based on the available biostratigraphy and δ¹³C trends, the studied Williston Basin curves are tied to the isotope curves from the North American Midcontinent, Québec (Anticosti Island) and Estonia, which confirm the Late Katian age (Aphelognathus divergens Conodont Zone) of the upper Red River Formation. The differences in the δ¹³C overall trend and absolute values, coupled with the petrographic and cathodoluminescence evidence, suggest that the carbon‐isotope record has been affected by the syndepositional environmental processes in the shallow and periodically isolated Williston Basin, and stabilized by later burial diagenesis under reducing conditions and the presence of isotopically more negative fluids.  相似文献   

四川盆地南充盐盆下、中三叠统测井响应特征及成钾条件分析   总被引：4，自引：0，他引：4  

陈科贵  李利  王刚  王林  陈愿愿  林新  常浩 《矿床地质》2014,33(5):1069-1080

通过野外地质调查及钻井资料复查,探明了雷口坡组及嘉陵江组顶、底界面特征。根据岩性组合、电性特征、旋回特征及地层厚度特征,对南充盐盆雷口坡组及嘉陵江组地层进行对比分析。在此基础上,对南充盐盆嘉陵江组及雷口坡组地层进行了重新梳理,得到南充盐盆盐岩层位的空间展布,及3个主要成盐段:嘉四段、嘉五2—雷一1亚段和雷三2亚段。通过大量单井分析,统计各成盐段石盐岩的单层厚度,结合各段岩性组合特征及放射性测井分析各成盐段的成钾条件;绘制各段石盐岩等厚图,得出各段盐岩分布范围及成盐中心,从而确定有利的成钾区。在广安构造的雷三2亚段,首次发现了杂卤石,否定了以往认为的雷三2亚段原始沉积石盐岩的海水中钾含量异常偏低的推测。  相似文献   

四川盆地奥陶系十字铺组与宝塔组接触关系新认识     

樊茹  卢远征  张学磊  张师本  段文哲  李鑫  邓胜徽 《地质学报》2013,87(3):321-329

内容提要：四川盆地奥陶系十字铺组和宝塔组自上世纪20年代命名以来,在地层学界一直被认为是连续沉积,整合接触。四川盆地东-南缘中-上奥陶统习水良村和武隆黄草两条剖面的牙形石生物地层与碳同位素地层学研究指示,十字铺组与宝塔组之间存在沉积间断,即二者并非整合接触关系。该不整合可与北美地区的M4/M5不整合面对比,二者可能是由桑比期早、晚期的海平面下降引发。与此时代相近的不整合在新疆巴楚地区、塔里木盆地亦有发现。由于十字铺组在四川盆地广泛分布于覆盖区,且岩性多以碳酸盐岩为主,因此不整合的发现将促使我们重新认识并评估该组的油气勘探潜力。  相似文献