Sur l’origine karstique et l’age plio-quaternaire des accumulations bréchiques dites ?brèches marines et paléocènes? d’Amélie-les-Bains (Pyrénées-Orientales, France)     

Joseph Canerot  Bernard Laumonier  Thierry Baudin 《Eclogae Geologicae Helvetiae》2006,99(1):49-64

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东海陆架盆地台北坳陷新地层单位——月桂峰组   总被引：2，自引：0，他引：2  

姜亮  李保华  钟石兰  张一勇  王建平 《地层学杂志》2003,27(3):210-211,215

在微体古生物和岩石地层学分析基础上 ,建立了东海陆架盆地台北坳陷新的地层单元——月桂峰组。月桂峰组分布于东海陆架盆地台北坳陷西带 ,由灰黑色泥岩、砂岩组成 ,上覆灵峰组、下伏石门潭组。它属古近纪古新世沉积 ,并推测可能为古新世早期。该地层相当于苏北盆地阜宁组一段。月桂峰组中微体化石特征表明月桂峰组当时沉积环境可能为淡水湖泊  相似文献   

Comparative paleofloristics of the Albian-Early Paleocene in the Anadyr-Koryak and North Alaska Subregions,part 2: The North Alaska Subregion     

A. B. Herman 《Stratigraphy and Geological Correlation》2007,15(4):373-384

The Albian-Paleocene phytostratigraphic scheme suggested in this work for the North Alaska Subregion of the North Pacific differs from the previous ones and includes three phytostratigraphic horizons of subregional extent and four plant-bearing beds. The scheme is based on distinguished successive stages in flora evolution, being substantiated by comprehensive data on the described floral (plant macrofossils) assemblages. As is established, sedimentation environments gradually changed during the Albian-Paleogene from the west of the subregion to the east so that the marine sedimentation and accumulation of sediments in general terminated in eastern areas later than western ones.  相似文献   

Dinoflagellate and foraminiferal biostratigraphy of the Gurpi Formation (upper Santonian–upper Maastrichtian), Zagros Mountains, Iran     

Ebrahim Ghasemi-Nejad  Mohammad Hadi Hobbi  Poul Schiler 《Cretaceous Research》2006,27(6):828-835

A rich dinoflagellate cyst assemblage has been recovered from an outcrop of the Gurpi Formation, the hydrocarbon source rock in the South Iranian Basin. Key dinoflagellates recorded in the section studied provide a means of correlation with zonation schemes for Australasia and north-west Europe. These include Eucladinium kaikourense, Nelsoniella aceras, Odontochitina spp., Cannosphaeropsis utinensis, Palaeocystodinium denticulatum and Dinogymnium spp. The assemblage points to a late Santonian–late Maastrichtian age for the Gurpi Formation. Dinoflagellate and planktonic foraminiferal evidence indicates the presence of a hiatus spanning the uppermost Maastrichtian to at least the lowermost Danian at the base of a glaucony-rich layer separating the Gurpi Formation from the overlying Pabdeh Formation. Palynofacies and lithofacies profiles suggest that the sediments were deposited in an open, relatively deep marine outer ramp environment belonging to ramp facies 8 and 9.  相似文献   

老挝巴根矿区钾盐矿层特征及其勘探意义     

张明明  张旭  潘林林 《化工矿产地质》2015,(2):72-76,84

老挝万象市巴根矿区位于万象平原东部呵叻盆地,是世界重要的钾盐矿分布区,钾盐资源丰富。通过对呵叻盆地的钾盐矿勘查工作,确定呵叻盆地钾盐矿矿石类型为中层钾石盐矿和下层光卤石矿两种,光卤石矿为主矿体;钾石盐矿为次矿体。本区钾盐矿分布范围较大、连续性较好、呈似层状,光卤石矿单工程KCl品位8.98%~22.91%(平均为18.90%),钾石盐矿单工程KCl品位22.36%~43.15%(平均品位31.29%)。经对本区钾盐矿层KCl资源量概略估算,属于大型矿床,可满足当前中小规模开采。下一步可对P3、P5、P7勘探线加密及外围布置勘探工作,重点对中层钾石盐矿矿层特征加以探明,寻求高级别资源储量,满足矿山生产需求。  相似文献   

Paleogene carbon isotope excursions in the Bunkers Hill borehole: Hampshire Basin, UK     

Emma Hodgson  Stephen T. Grimes  Gregory D. Price  Meriel E.J. Fitzpatrick  Malcolm B. Hart  Melanie J. Leng 《Proceedings of the Geologists' Association. Geologists' Association》2011,122(3):460-471

This study demonstrates that the Bunkers Hill borehole, which is located within the Hampshire Basin, contains a carbon isotope excursion (CIE) in the Upnor Formation followed by a positive recovery from another CIE within the overlying Reading Formation. This study has also shown that the CIE in the Upnor Formation predates the Paleocene/Eocene Thermal Maximum (PETM), while the carbon isotope recovery at the base of the Reading Formation is most likely related to it. The positive carbon isotope trend, before a return to more negative values, seen throughout the majority of the Reading Formation can also be seen in coeval deposits in the Jubilee 404T borehole in the London Basin and in the Tienen Formation in the Doel and Kallo boreholes from the Belgium Basin. This indicates that this post-PETM carbon isotope signal may, therefore, be regional if not global in nature.  相似文献   

Calcareous nannofossil changes linked to climate deterioration during the Paleocene-Eocene thermal maximum in Tarim Basin,NW China     

Wenxin Cao  Dangpeng Xi  Mihaela C.Melinte-Dobrinescu  Tian Jiang  Sherwood W.Wise Jr.  Xiaoqiao Wan 《地学前缘(英文版)》2018,9(5):1465-1478

The Paleocene-Eocene Thermal Maximum(PETM) event was a dramatic global warming w55.93 Ma ago that resulted in biological extinction events, lithological changes, and major deviations in σ13 C and σ18 O.The southwestern Tarim Basin of China exposes successive Paleogene strata as a result of Tethys evolution and is considered an ideal region for PETM research.Based on calcareous nannoplankton biostratigraphy, we also used stable isotopes and XRD to analyse the Paleocene-Eocene transition in the Tarim Basin. At the Bashibulake Section, the PETM interval is characterized by(1) an abrupt negative shifts in σ13 C_(org), σ13 C_(carb) and σ18 O(-3%, -4.5% and -3%respectively);(2) an obvious negative correlation between the K-mode(Discoaster, Fasciculithus, Ericsonia, Sphenolithus and Rhomboaster) and r-mode(Biscutum, Chiasmolithus, Toweius) nannofossil taxa coincident with a robust Rhomboaster-Discoaster assemblage; and(3) a significant increase in the percentage of detrital input along with an increase in gypsum content. In the upper part of the Qimugen Formation Micrantholithus and Braarudosphaera are commonly found right up to the top where most of the nannofloras suffer a sharp decrease. In the overlying Gaijitage Formation, calcareous nannofossils disappear completely. These events indicate that the southwestern Tarim Basin was a warm shallow continental shelf during the deposition of the Qimugen Formation. From the early Eocene, the environment changed conspicuously. Evaporation increased and sea level fell, which led to an acid climate.This climate mode continued within the youngest unit studied, the Gaijitage Formation, characterized by the deposition of thick evaporates. Consequently, most of the marine plankton, i.e. calcareous nannoplankton, became disappear, because of the significant climate shift.  相似文献   

Petrography and geochemistry of Paleocene–Eocene limestones in the Ching-dar syncline, eastern Iran     

S.HalimehHashemiAzizi  GholamrezaMirabShabestari  AhmadrezaKhazaei 《地学前缘(英文版)》2014,5(3):429-438

The Ching-dar syncline is located to the west of the city of Birjand, in the east of han. The ca. 500 m thick studied section at the eastern flank of the syncline contains a sequence of almost continuous shallow- marine limestones that exhibit no major sedimentary breaks or evidence for volcanic activity. Skeletal grains consist of large benthic foraminifera and green algae whereas non-skeletal grains are mostly peloids and intraclasts. They were deposited on a shallow-marine carbonate ramp. The limestones have undergone extensive diagenetic processes with varying intensities, the most important of which are micritization, cementation, compaction （chemical and mechanical）, internal filling and stylolitization. Chemical analysis of the limestone samples revealed high calcium and low magnesium content. Major and minor element values were used to determine the original carbonate mineralogy of these lime- stones. Petrographic evidence and elemental values indicate that calcite was the original carbonate mineral in the limestones of the Ching-dar syncline. The elemental composition of the Ching-dar car- bonates also demonstrates that they have stabilized in a meteoric phreatic environment. Variation of Sr/ Ca vs. Mn values suggests that diagenetic alteration occurred in an open geochemical system.  相似文献   

江陵凹陷古新统盐类矿物沉积特征及其成钾指示意义   总被引：1，自引：1，他引：0  

沈立建  刘成林  徐海明  王春连  王立成  刘宝坤  张林兵 《矿床地质》2014,33(5):1020-1030

在对江陵凹陷中GK1、GK2、SK3和B103井岩芯进行详细观察的基础上,借助X射线衍射、扫描电镜、薄片鉴定等手段,确认了在古新统有多种盐类矿物存在,并对盐类矿物特征和矿物组合特征进行了分析。江陵凹陷含盐系地层的矿物种类、组合比较简单,目前发现的盐类矿物有碳酸盐、硫酸盐、氯化物三大类。古新统沙市组沉积时期,出现了大量的盐类矿物,主要为石盐、硬石膏、钙芒硝及无水芒硝,此外,应有少量—微量的钾石盐。作为干热指示矿物的钙芒硝和无水芒硝在沙市组广泛发育,可以推断出江陵凹陷在古新统沙市组时期的古气候属于干热型,此时湖水蒸发作用显著增高,导致古盐湖演化程度较高,向干盐湖阶段发展;而到了新沟嘴组沉积时期,发生湖侵,盐湖水体变深、盐度降低,盐湖遭受淡化。初步判断江陵凹陷古近系沙市组具有较好的成钾条件。  相似文献   

青藏高原古新世构造岩相古地理     

梁银平  张克信  宋博文  王国灿  徐亚东  陈锐明  陈奋宁  骆满生 《地质通报》2013,32(1):67-74

在系统分析青藏高原及邻区古新世残留盆地类型、形成构造背景、岩石地层序列的基础上,对青藏高原古新世构造岩相古地理演化特征进行讨论:青藏高原西北部的西昆仑,北部的阿尔金、祁连、西秦岭,东北部的松潘-甘孜和南部的冈底斯陆缘弧带,以及北部的阿拉善古陆和南部的上扬子古陆和印度古陆为隆起剥蚀区。西宁-兰州、成都和班戈地区零星分布个别构造压陷湖盆。高原西部和南部为新特提斯海。南部的特提斯-喜马拉雅海区的古地理格局为萨嘎以西为残余洋盆,以东为前陆盆地。由此提出,白垩纪晚期—古新世印度板块与欧亚板块的碰撞起始于东部构造结,新特提斯洋的闭合是自东向西进行的。  相似文献