山东淄博煤田晚石炭世——早二叠世植物群落特征

山东淄博煤田晚石炭世—早二叠世植物化石经鉴定,共计37属104种,其中包括11个新种。分析了本区植物化石的埋藏类型,根据各类植物的生活习性和生境,将晚石炭世—早二叠世植物群划分为五个植物群落,讨论了它们的多度、成分、结构和生活型等特征,并采用信息函数数理统计方法,应用电子计算机对各植物群落的分异度和均衡度进行了计算。     

新疆东部三塘湖盆地构造演化及其石油地质意义

三塘湖盆地形成于晚古生代以后,是一个构造演化复杂的中小型含油气盆地,经历了石炭纪到早二叠世盆地基底形成阶段、晚二叠世到白垩纪盆地发育阶段和第三纪以来的后期盆地改造阶段。在基底形成阶段,早石炭世为古准噶尔洋盆俯冲的活动大陆边缘时期,晚石炭世进入哈萨克斯坦板块和西伯利亚板块碰撞造山时期,早二叠世为碰撞后伸展转换时期。从晚二叠世以后,盆地进入发育阶段。晚二叠世为造山后伸展断陷时期,三叠纪末为挤压隆升时期,侏罗纪-早白垩世盆地进入拗陷时期,早白垩世末期为挤压逆冲时期。从第三纪以来,盆地进入了后期的改造阶段。在整个盆地演化过程中,晚二叠世盆地处于张性成盆环境,并沉积发育了上二叠统芦草沟组泥灰岩、上三叠统小泉沟群和下-中侏罗统水西沟群以暗色泥岩为主的三套烃源岩。受其区域性挤压构造背景影响,早白垩世末期和晚始新世是盆地两个油气成藏关键时刻,特别是新生代晚期盆地的改造对油气能否进入成熟生油阶段具有重要意义。     

论峨眉地幔热柱活动的时效性

峨眉地幔热柱是目前世界上公认的少数几个地幔热柱之一.但是,它的活动时间一直是地学界争论的热点,观点一认为:它是指发生于早晚二叠世之间大量喷发的峨眉山玄武岩浆时期;观点二认为:它起源于晚泥盆世,包含石炭纪、二叠纪以及整个中生代,一直延续到新生代早期.作者通过对中国西南地区峨眉山玄武岩及相关岩浆活动的地质学、地球化学研究,...     

Discovery of Cathaysiodendron Lee from the Early Carboniferous of Jingyuan, Gansu, western China

As one of the representative members of the Late Palaeozoic Cathaysian flora, Cathaysiodendron has been previously recorded from the Early Permian Taiyuan and Shanxi Formations in north China. The species of Cathaysiodendron presented here are from the lower member of Chouniugou Formation of Ciyao, Jingyuan, Gansu. The overlying marine beds yield fusulinids that are of Visean age in western Europe and conodonts of the Datang Stage in south China, so that the age of the bed containing Cathaysiodendron as Visean, Early Carboniferous, is well constrained. Such a record of Cathaysiodendron is significant in terms of Carboniferous phytogeography and the evolution of the Cathaysian Lepidophytes. A new species, Cathaysiodendron jingyuanense Wang & Wu sp. nov. is described and a second one mentioned.     

广州地区前华夏植物群研究

广州地区晚泥盆世至早石炭世植物群计 2 3属 4 1种,以真蕨纲和种子蕨纲为主,石松纲居次,另外还有少量楔叶纲、科达纲及种子化石.按地层分布当前植物群可分为沙水岗组植物组合、龙江组植物组合及测水组植物组合.分析该植物群的组成特征,其性质属前华夏植物群     

Late Paleozoic magmatism in South China:Oceanic subduction or intracontinental orogeny?

A gneissic granite with an U-Pb age of 313±4 Ma was found in northeastern Fujian Province,South China.It is an S-type granite characterized by high K2O,Al2O3 and low SiO2,Na2O contents with high A/CNK ratio of 1.22 for the whole rock.Zircons with stubby morphology from the gneissic granite yield 206 Pb/238 U ages ranging from 326 to 301 Ma with a weighted average age of 313±4 Ma,and negative εHf(t) values from -8.35 to -1.74 with Hf model ages (TCDM) of 1.43 to 1.84 Ga.This S-type granite probably originated from late Paleoproterozoic crust in intracontinental orogeny.Integrated with previous results on paleogeographic reconstruction of South China,the nature of Paleozoic basins,Early Permian volcanism and U-Pb-Hf isotope of detrital zircons from the late Paleozoic to early Mesozoic sedimentary rocks,we suggest the occurrence of a late Paleozoic orogeny in the eastern Cathaysia Block,South China.This orogenic cycle includes Late Carboniferous (340-310 Ma) orogeny (compression) episode and Early Permian (287-270 Ma) post-orogenic or intraplate extension episode.Therefore,the late Paleozoic magmatism in the southeastern South China probably occurred during the intraplate orogeny rather than the arc-related process.     

Reidentification of the ore-hosted strata age of Sawaya’ erdun gold deposit in Xinjiang, southwestern Tianshan

Identification of the coral andSchwagerina in the ore-hosted strata of Sawaya’ erdun gold deposit shows that the fossil age ranges from the late Carboniferous to the early Permian. By combining this with the Rb-Sr isochron age, it is concluded that the ore-hosted strata age is possibly the late Carboniferous rather than the Silurian and Devonian, even impossibly the Precambrian.     

Dynamics for multistage pool formation of Lunnan low uplift in Tarim Basin

Lunnan area in the Tarim Basin has become animportant onshore oil production base in China. Formationof the oil and gas pools in the low uplift of Lunnan has ex-perienced a comparatively complex process of dynamics.Based on the hydrocarbon generation period of source rocks,the formation period of cap rocks and traps, the analysis oforganic inclusion and the analysis of bitumen in the reservoir,this paper draws the conclusion that the low uplift area ofLunnan has experienced three pool formation periods: thePermian period, the Cretaceous-Early Tertiary period andthe Late Tertiary-Quaternary period and two oil and gasreservoir adjustment periods: the Late Permian period andthe Late Tertiary-Quaternary period. The comprehensivestudy indicates that the large-scale Ordovician buried hill,formed in Early Hercynian, became the reservoir during thePermian period, because the Cambrian-Lower Ordovicianoil was discharged laterally into the reservoir along the topof the Ordovician weathering crust from south to north. Thereservoir experienced a complicated process—reconstruc-tion in the end of Permian, adjustment in Cretaceous-EarlyTertiary and re-discharging process in Late Tertiary-Qua-ternary, leading to the early original heavy oil reservoir ofmarine facies and the late original light oil reservoir and gaspool. Carboniferous, Triassic and Jurassic oil and gas reser-voirs result from upward adjustment and re-distribution ofOrdovician oil and gas reservoirs. Of those results, the for-mation of Triassic-Jurassic oil and gas pools came under theinfluence of the northward-tilting structure. The oil and gassourcing from the different hydrocarbon source rock inter-vals vertically migrated into the base unconformity of Trias-sic system. Then the oil and gas migrated laterally fromnorth to south and accumulated into the reservoir.     

Permian palynofloras from Yongchang and Sunan of Gansu Province and their phytoprovincial characteristics

The Early Permian (Shansi + Lower Shihhotse Formations) palynofloras of Longshoushan are dominated by Cathaysian-Euramerican common forms, mainly composed of pteridophytic and pteridospermous spores. But up to the Lower Shihhotse Formation, gymnosperms greatly developed, and they possibly already dominated the vegetation in the Upper Shihhotse Formation; while in the late Late Permian, they indicate a strong colour of Subangara area. In other words, during the whole Permian, the Cathaysian flora had a history from prosperity to decline, and Subangara plants might have had a reverse tendency there.     

川中地区龙王庙组洞穴充填物特征及油气地质意义

依据洞穴充填物岩性、孢粉化石、主元素、痕量元素和稀土元素特征分析,结合区域构造演化资料,探讨了川中下寒武统龙王庙组大型洞穴的形成时期和充填过程。洞穴充填泥中孢粉化石时代为石炭纪—早白垩世,泥质岩具有高 B 含量、低 Sr／Ba、稀土元素配分模式差别大的元素地化特征。认为龙王庙组洞穴主要形成于石炭纪—早二叠世古隆起大规模隆升暴露期,为风化壳喀斯特作用和顺层喀斯特作用叠加形成的,并经历了石炭纪—早二叠世的沉积充填和潜流携带古隆起高部位物质充填,及中生代—新生代构造活动期地表水携带溶解残余物沿断裂下渗充填过程。邻近龙王庙组尖灭线,受石炭纪—早二叠世风化壳喀斯特作用和顺层喀斯特作用影响的颗粒滩发育带为川中龙王庙组储层发育最有利地区。