Apart from previously reported Small Shelly Fossils （SSFs）, a macroscopic fossil assemblage, comprising abundant algae, cone-shaped tubular fossil forms, and probable impressions of a megascopic metazoan, comes from...Apart from previously reported Small Shelly Fossils （SSFs）, a macroscopic fossil assemblage, comprising abundant algae, cone-shaped tubular fossil forms, and probable impressions of a megascopic metazoan, comes from the Lower Cambrian Yanjiahe Formation in the Yangtze Gorges area of western Hubei Province, south China. The visible fossils are preserved in thinlaminated siltstone or muddy siltstone intercalated between 8-15 ram-thick carbonate deposits, probably representing sedimentary settings of a constrained local depression in the shallow water carbonate platform during the Early Cambrian Meishucunian Stage. The macroscopic fossil association provides significant fossil evidence about the evolution of life from the late Precambrian to the ＇Cambrian explosion＇ interval.展开更多
In order to evaluate the geological characteristics and gas-bearing factors of Niutitang Formation within the Lower Cambrian of northern Guizhou,the Huangping area located at the southern edge of the ancient uplift be...In order to evaluate the geological characteristics and gas-bearing factors of Niutitang Formation within the Lower Cambrian of northern Guizhou,the Huangping area located at the southern edge of the ancient uplift belt of Xuefeng Mountain was selected as the target area,and Well Huangdi 1 was drilled for the geological survey of shale gas.Through geological background analysis and well logging and laboratory analysis such as organic geochemical test,gas content analysis,isothermal adsorption,and specific surface area experiments on Well Huangdi 1,the results show that the Niutitang Formation is a deep-water shelf,trough-like folds and thrust fault.The thickness of black shale is 119.95 m,of which carbonaceous shale is 89.6 m.The average value of organic carbon content is 3.55%,kerogen vitrinite reflectance value is 2.37% and kerogen type is sapropel-type.The brittle mineral content is 51%(quartz 38%),clay mineral content is 38.3%.The value of porosity and permeability are 0.5%and 0.0014 mD,which the reservoir of the Niutitang Formation belongs to low permeability with characteristics of ultra-low porosity.The gas content is 0.09‒1.31 m^3/t with a high-value area and a second high-value area.By comparing with the geological parameters of adjacent wells in the adjacent area,the accumulation model of“sediment control zone,Ro control zone,structure controlling reservoir”in the study area is proposed.Therefore,deep-water shelf-slope facies,Ro is between high maturity-early stage of overmaturity and well-preserved zones in the Niutitang Formation in this area are favorable direction for the next step of shale gas exploration.展开更多
The Lower Cretaceous Guantou Formation is known as an important horizon for the Cretaceous petrified woods in southern China. Though abundant Cretaceous wood remains have been found in this formation, only one species...The Lower Cretaceous Guantou Formation is known as an important horizon for the Cretaceous petrified woods in southern China. Though abundant Cretaceous wood remains have been found in this formation, only one species has been recognized. A new coniferous wood, Brachyoxylon zhejiangense sp. nov. is described from the Lower Cretaceous Guantou Formation in Xinchang of Zhejiang Province, southeastern China. Anatomically, the new species is characterized by obscure annual rings, mixed type of radial pitting, araucarioid cross-field pits and uniseriate xylem rays. The finding of Brachyoxylon zhejiangense sp. nov. represents the first well-defined record of Brachyoxylon in southeastern China, and enriches the diversity of the Early Cretaceous petrified wood in southern China. Additionally, the new finding sheds new light on further understanding the floral composition, especially the forest vegetation type of the southern phytoprovince in the late Early Cretaceous. Diverse compressed leaf fossils of Cheirolepidiaceae have been described from the Guantou Formation in the fossil locality of the present petrified wood. The co-occurrence of Brachyoxylon zhejiangense sp. nov. and those cheirolepidiaceous leaf fossils provide additional evidences to support that Brachyoxylon may be systematically related to the Cheirolepidiaceae.展开更多
基金funded by the National Natural Science Foundation of China(40332016,04062003,40702005)National"973"Project(2006CB806401)"as well as by the Program for Changjiang Scholars and Innovative Research Team in Universities(G2000077702) and the Sino-Japan Cooperative Project
文摘Apart from previously reported Small Shelly Fossils （SSFs）, a macroscopic fossil assemblage, comprising abundant algae, cone-shaped tubular fossil forms, and probable impressions of a megascopic metazoan, comes from the Lower Cambrian Yanjiahe Formation in the Yangtze Gorges area of western Hubei Province, south China. The visible fossils are preserved in thinlaminated siltstone or muddy siltstone intercalated between 8-15 ram-thick carbonate deposits, probably representing sedimentary settings of a constrained local depression in the shallow water carbonate platform during the Early Cambrian Meishucunian Stage. The macroscopic fossil association provides significant fossil evidence about the evolution of life from the late Precambrian to the ＇Cambrian explosion＇ interval.
基金This research was financially supported by the National Science and Technology Major Project(2016ZX05034)project of China Gelogical Survey(DD20160181).
文摘In order to evaluate the geological characteristics and gas-bearing factors of Niutitang Formation within the Lower Cambrian of northern Guizhou,the Huangping area located at the southern edge of the ancient uplift belt of Xuefeng Mountain was selected as the target area,and Well Huangdi 1 was drilled for the geological survey of shale gas.Through geological background analysis and well logging and laboratory analysis such as organic geochemical test,gas content analysis,isothermal adsorption,and specific surface area experiments on Well Huangdi 1,the results show that the Niutitang Formation is a deep-water shelf,trough-like folds and thrust fault.The thickness of black shale is 119.95 m,of which carbonaceous shale is 89.6 m.The average value of organic carbon content is 3.55%,kerogen vitrinite reflectance value is 2.37% and kerogen type is sapropel-type.The brittle mineral content is 51%(quartz 38%),clay mineral content is 38.3%.The value of porosity and permeability are 0.5%and 0.0014 mD,which the reservoir of the Niutitang Formation belongs to low permeability with characteristics of ultra-low porosity.The gas content is 0.09‒1.31 m^3/t with a high-value area and a second high-value area.By comparing with the geological parameters of adjacent wells in the adjacent area,the accumulation model of“sediment control zone,Ro control zone,structure controlling reservoir”in the study area is proposed.Therefore,deep-water shelf-slope facies,Ro is between high maturity-early stage of overmaturity and well-preserved zones in the Niutitang Formation in this area are favorable direction for the next step of shale gas exploration.
基金supported by the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant Nos. XDB18000000 and XDB26010302)the State Key Program of Research and Development of Ministry of Science and Technology, China (Grant No. 2016YFC0600406)+2 种基金the National Natural Science Foundation of China (Grant Nos. 41302004, 41688103, and 41790454)the State Key Laboratory of Palaeobiology and Stratigraphy (NIGPAS, CAS) (Grant Nos. 133113 and 173124)the Special Fund of Liaoning Provincial Universities' Fundamental Scientific Research Project (Grant No. LQN201718)
文摘The Lower Cretaceous Guantou Formation is known as an important horizon for the Cretaceous petrified woods in southern China. Though abundant Cretaceous wood remains have been found in this formation, only one species has been recognized. A new coniferous wood, Brachyoxylon zhejiangense sp. nov. is described from the Lower Cretaceous Guantou Formation in Xinchang of Zhejiang Province, southeastern China. Anatomically, the new species is characterized by obscure annual rings, mixed type of radial pitting, araucarioid cross-field pits and uniseriate xylem rays. The finding of Brachyoxylon zhejiangense sp. nov. represents the first well-defined record of Brachyoxylon in southeastern China, and enriches the diversity of the Early Cretaceous petrified wood in southern China. Additionally, the new finding sheds new light on further understanding the floral composition, especially the forest vegetation type of the southern phytoprovince in the late Early Cretaceous. Diverse compressed leaf fossils of Cheirolepidiaceae have been described from the Guantou Formation in the fossil locality of the present petrified wood. The co-occurrence of Brachyoxylon zhejiangense sp. nov. and those cheirolepidiaceous leaf fossils provide additional evidences to support that Brachyoxylon may be systematically related to the Cheirolepidiaceae.
文摘澄江生物群是认识寒武纪生命大爆发的重要窗口,它的分布范围一直仅限于滇东地区,最近在贵州遵义松林牛蹄塘组底部页岩中发现有Naronia,Archotuba conoidalis,Isoxys,Perspicaris,Lingulepis,Tsunyidiscus,Scenella,水母状化石(medusiform fossil),海绵动物化石Leptomitus,类似半索动物杆壁虫Rhabdopleura化石,软舌螺类Hyolithids,宏观藻类和疑源类化石Zunyiphyton perelegans Yang et Zhao,1999,Yuknessia sp.,Longenema Ding,1996,Sphaerocongregus variabilis等。其中有一部分是属于澄江生物群分子,这是云南省外澄江生物群分子的新发现。由于生物群之下40m处还产大量海绵动物、高肌虫和藻类化石等组成的松林生物群,其上又有下寒武统明心寺组古杯动物群,因此,这一生物群的发现对研究早寒武世生物的演化也具有一定的科学意义,同时,对澄江生物群的古生态学研究也具有重要意义。
文摘通过野外实地观察、样品采集及系列实验分析发现,皖南下扬子区下寒武统荷塘组页岩在研究区内分布广泛,沉积厚度大（约60~360 m）,有机质丰度高（达0.5%~7.2%）,热演化程度较高（Ro为2.0%~5.5%）,达高-过成熟阶段晚期,具有较好的生烃潜力;储集层孔隙度平均为0.716%,为游离气提供了一定的储存空间,等温吸附实验测得吸附气含量平均为0.443 cm3/g,表明研究区页岩具有较强的吸附能力。通过综合研究认为,石台—黟县—泾县—宁国一带为今后的有利勘探区,分布面积约9 100 km2.
