Palaeoenvironmental setting of the Kangdian area, southwest China, in Proterozoic Datian–Meidang time

1987 ◽  
Vol 124 (2) ◽  
pp. 143-147
Author(s):  
Wang Fuxing
Keyword(s):  
Oxygen Isotope ◽  
Carbonate Rocks ◽  
Southwest China ◽  
Sedimentary Basin ◽  
Size Range ◽  
Southwestern China ◽  
Isotope Data ◽  
Yunnan Area ◽  
First Time ◽  
Important Basis

AbstractNumerous acritarchs and stromatolites have been discovered and studied from the Proterozoic Datian Formation of the Kunyang Group and the Meidang Formation of the Dongchuan Group in Sichuan–Yunnan area, southwestern China, and more than 80 oxygen isotope data have been obtained from the sediments. Based on size-range and variation of non-filamentous acritarchs, the development of columnar stromatolites and the 18O/16O values of stromatolitic and nonstromatolitic carbonate rocks, the author proposes, for the first time, a palaeoenvironmental framework of the Kangdian area during Datian–Meidang time.Although the usefulness of Precambrian acritarchs and oxygen isotope values in palaeoenvironmental analysis of a sedimentary basin is just beginning to be understood, it is evident that these data are an important basis for palaeoenvironmental studies.

scholarly journals Triple oxygen isotope variations in magnetite from iron-oxide deposits, central Iran, record magmatic fluid interaction with evaporite and carbonate host rocks

Geology ◽  
2019 ◽  
Vol 48 (3) ◽  
pp. 211-215 ◽  
Author(s):  
Stefan T.M. Peters ◽  
Narges Alibabaie ◽  
Andreas Pack ◽  
Seann J. McKibbin ◽  
Davood Raeisi ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Oxygen Isotope ◽  
Carbonate Rocks ◽  
Isotope Composition ◽  
Central Iran ◽  
Magmatic Fluid ◽  
Isotope Data ◽  
O Isotopes ◽  
Magmatic Fluids ◽  
O Isotope

Abstract Oxygen isotope ratios in magnetite can be used to study the origin of iron-oxide ore deposits. In previous studies, only 18O/16O ratios of magnetite were determined. Here, we report triple O isotope data (17O/16O and 18O/16O ratios) of magnetite from the iron-oxide–apatite (IOA) deposits of the Yazd and Sirjan areas in central Iran. In contrast to previous interpretations of magnetite from similar deposits, the triple O isotope data show that only a few of the magnetite samples potentially record isotopic equilibrium with magma or with pristine magmatic water (H2O). Instead, the data can be explained if magnetite had exchanged O isotopes with fluids that had a mass-independently fractionated O isotope composition (i.e., MIF-O), and with fluids that had exchanged O isotopes with marine sedimentary carbonate rocks. The MIF-O signature of the fluids was likely obtained by isotope exchange with evaporite rocks of early Cambrian age that are associated with the IOA deposits in central Iran. In order to explain the triple O isotope composition of the magnetite samples in conjunction with available iron isotope data for magnetite from the deposits, we propose that magnetite formed from magmatic fluids that had interacted with evaporite and carbonate rocks at high temperatures and at variable water/rock ratios; e.g., magmatic fluids that had been released into the country rocks of a magma reservoir. Additionally, the magnetite could have formed from magmatic fluids that had exchanged O isotopes with SO2 and CO2 that, in turn, had been derived by the magmatic assimilation and/or metamorphic breakdown of evaporite and carbonate rocks.

Soft anatomy of sunellid arthropods from the Chengjiang Lagerstutte, Lower Cambrian of southwest China

2007 ◽  
Vol 81 (6) ◽  
pp. 1412-1422 ◽  
Author(s):  
Xingliang Zhang ◽  
Degan Shu
Keyword(s):  
Lower Cambrian ◽  
Southwest China ◽  
Systematic Position ◽  
The Body ◽  
Southwestern China ◽  
Burgess Shale ◽  
The Family ◽  
Trunk Limbs ◽  
First Time

Two bivalved arthropods of the family Sunellidae Huo, 1965 are described from the Lower Cambrian Helinpu Formation of southwestern China: Sunella cf. shensiensis Huo, 1965 and Combinivalvula chengjiangensis Hou, 1987. Both taxa preserve soft anatomies, described here for the first time, including a pair of lateral eyes and a possible median eye, a trunk carrying flaplike appendages, and a simple gut with caeca. The family Sunellidae includes three genera: Sunella Huo, Combinivalvula Hou, and Jinningella Huo and Shu. In contrast to most other Cambrian arthropods with a larger bivalved carapace, especially those from the Burgess Shale–type deposits, sunellids lack a limbless abdomen protruding posteriorly beyond the carapace. This, coupled with a combination of a number of snared features (e.g., the presence of cardinal spines and distinctive anterodorsal sulcus, elongated valves, and median eye), appears to support sunellids as a clade. The distinctive anterodorsal sulcus extending from the anterodorsal corner to the anteromedian part of the carapace is regarded as an autapomorphy for this clade. Sunellids resemble Isoxys Walcott, 1890 to which they may be closely related; both possess a bivalved, elongated carapace with cardinal spines that almost entirely covers the body. However, neither cephalic appendages nor proximal portions of trunk limbs are visible in sunellids, and thus, their systematic position remains uncertain.

scholarly journals Occurrence of the belemnite Actinocamax plenus in the - Cenomanian of SE France and its significance

1996 ◽  
Vol 43 ◽  
pp. 68-77
Author(s):  
A. S. Gale ◽  
W K. Christensen
Keyword(s):  
Oxygen Isotope ◽  
Cold Temperature ◽  
Paris Basin ◽  
Cold Event ◽  
Isotope Data ◽  
Oxygen Isotope Data ◽  
First Time ◽  
Se France

The Late Cenomanian belernniteActinocamaxplenus is recorded from the Tethyan Realm for the first time, from les Lattes in the Alpes de Haute-Provence, southeastem France. This exceptionally southerly occurrence of the species is coincident with a cold temperature event, the Plenus Cold Event, registered by oxygen isotope data from southeast England. The record of A. plenus from les Lattes enables a precise correlation to be made with the Plenus Marls of the Anglo-Paris Basin.

Tracing the emerald origin by oxygen isotope data: the case of Sandawana, Zimbabwe

2004 ◽  
Vol 336 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Johannes C.(Hanco) Zwaan ◽  
Alain Cheilletz ◽  
Bruce E. Taylor
Keyword(s):  
Oxygen Isotope ◽  
Isotope Data ◽  
Oxygen Isotope Data

A review of the non-lyctine powder-post beetles of Yunnan (China) with a new genus and new species (Coleoptera: Bostrichidae)

Zootaxa ◽  
2022 ◽  
Vol 5091 (4) ◽  
pp. 501-545
Author(s):  
YI-FENG ZHANG ◽  
LING-ZENG MENG ◽  
ROGER A. BEAVER
Keyword(s):  
New Species ◽  
Southeast Asia ◽  
Yunnan Province ◽  
New Genus ◽  
Southwest China ◽  
Geological History ◽  
Yunnan Region ◽  
Palearctic Region ◽  
History Of ◽  
First Time

The powder post beetles (Coleoptera: Bostrichidae) (except Lyctinae) of Yunnan Province in Southwest China are reviewed for the first time. Keys to twenty-six genera and fifty-two species from the Yunnan region are provided. One new genus and seven new species are described: Dinoderus (Dinoderastes) hongheensis sp. nov., Dinoderus (Dinoderastes) nanxiheensis sp. nov., Gracilenta yingjiangensis gen. nov., sp. nov., Calonistes vittatus sp. nov., Calophagus colombiana sp. nov., Xylodrypta guochuanii sp. nov. and Xylodrypta zhenghei sp. nov.. Fourteen species are recorded in China for the first time. The bostrichid fauna of Yunnan is compared with those of the neighbouring bio-geographically related Southeast Asian and Himalayan regions. The fauna has a close affinity with that of tropical Southeast Asia and a much weaker relationship with the Palearctic region. The differences with the Himalayas may reflect the separate evolutionary and complex geological history of the two areas.

Novel Integrated Approach for Complex Carbonate Reservoirs Testing with Wireline Formation Tester: Yurubcheno-Tokhomskoye Field Cases Study

2021 ◽  
Author(s):  
Yakov Dzhalatyan ◽  
Mikhail Charupa ◽  
Aydar Galiev ◽  
Yevgeniy Karpekin ◽  
Sergey Egorov ◽  
...  
Keyword(s):  
Carbonate Rocks ◽  
Fractured Reservoirs ◽  
Integrated Approach ◽  
Carbonate Sediments ◽  
Drilling Mud ◽  
Acoustic Reflection ◽  
Resistivity Logging ◽  
First Time ◽  
Fluid Inflow ◽  
Low Porosity

Abstract In the presented paper, the object of the study are carbonate rocks of the Riphean and clastic-carbonate rocks of Vendian-Cambrian ages, uncovered by the well drilled at Yurubcheno-Tokhomskoye field. These reservoirs are characterized by extremely low porosity (1-4%) and determining saturation nature and fluid contacts cannot be reliably solved by conventional wireline petrophysical logging. Solutions to these problems are provided by interval testing using wireline formation evaluation testing tool (WFT). However, to obtain quality results from WFT testing it is important to identify porous intervals first by using advanced wireline logging services which are sensitive to porosity and fractures. In order to select the optimal WFT toolstring combination and to prospective testing intervals, advanced petrophysical wireline logging suit ran first. Porous reservoirs were identified from density, neutron and nuclear magnetic resonance evaluation. Saturation evaluated through dielectric and induction-based resistivity logging. In fracture-vug type reservoir, the main inflow of formation fluid into the well is provided from fractures, so it was very important to allocate conductive fractures to plan test intervals for WFT accordingly. based on imagers evaluation, fractures and faults were visualized; using Stoneley's wave conductive fractures, not clogged with drilling mud solids were identified; borehole acoustic reflection survey was used to segregate large fractures that propagated in the reservoir; During WFT logging, a total of 23 intervals were tested, for 8 of which reservoir fluid inflow was achieved, in all others, mainly with low porosity or single non-conductive fracture, the inflow was not achieved or was insignificant. According to the results of WFT testing, the nature of saturation for clastic-carbonate sediments of Vendian age was determined. Inflow of formation fluid (oil and water) from Riphean fractured reservoirs was achieved from 6 intervals, with identified fractures according to described above advanced logging suit. In addition, pressure transient analysis was performed, to measure the formation pressure, define pressure gradient curves and assess the fluids contact level with high confidence, for the first time for this field.

SECONDARY CHANGES IN CARBONATE ROCKS OF OIL AND GAS COMPLEXES

2020 ◽  
pp. 18-23
Author(s):  
M.A. Tugarova
Keyword(s):  
Carbonate Rocks ◽  
Oil And Gas ◽  
Carbonate Reservoirs ◽  
Fundamental Importance ◽  
Schematic Diagram ◽  
Reservoir Properties ◽  
Physico Chemical ◽  
Chemical Conditions ◽  
First Time

The article considers the secondary transformations of carbonate rocks of oil and gas complexes, which are of fundamental importance in the formation of reservoir properties. For the first time, a schematic diagram, illustrating the regularities of secondary processes in carbonate reservoirs and their relationship with the physico-chemical conditions of the stratosphere is proposed.

ISOTOPE-GEOCHEMICAL FEATURES OF AUTHENIC CARBONATES OF THE YU1 PRODUCING HORIZON OF THE VERKH-TARSKOYE OIL FIELD (SOUTH OF WESTERN SIBERIA)

2020 ◽  
pp. 20-28
Author(s):  
L. G. Vakulenko ◽  
◽  
O. D. Nikolenko ◽  
D. A. Novikov ◽  
P. A. Yan ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Carbonate Rocks ◽  
Western Siberia ◽  
Oil Field ◽  
Third Generation ◽  
The Third ◽  
First Time ◽  
Different Sources ◽  
Sources Of Co2 ◽  
Comprehensive Study

A comprehensive study of the composition of sand and silt deposits of the Yu1 horizon of the Vasyuganskaya Formation upper part of the Verkh-Tarskoye oil field has been carried out. Associations of authigenic minerals have been determined in their cement, among which the calcite is the most widespread. According to petrographic parameters, three generations of calcite have been identified for which detailed isotopicgeochemical and ultramicroscopic studies were carried out for the first time. Wide and multi directional changes in the isotopic composition of carbon and oxygen and in the chemical composition of carbonate minerals were recorded, they indicate significant variations in the conditions of diagenesis and catagenesis, primarily temperature, and different sources of CO2. Significant variations in the isotopic composition of formation waters and its relationship with the isotopic composition of carbonates have been established. Thus, a narrow interval of close δ13C values was revealed, amounting to –10.5 to –9.1 ‰ in the formation waters of group II, and from –10.7 to –9.1 ‰ in calcites of the third generation. The source of CO2 in this system should be considered a carbon dioxide, which is formed in the process of metamorphism of carbonate rocks of the Paleozoic age.

Gerhardtia yunnanensis (Agaricales, Lyophyllaceae), a new species from southwest China

Phytotaxa ◽  
2021 ◽  
Vol 484 (2) ◽  
pp. 217-226
Author(s):  
MAN MU ◽  
HONG-YAN HUANG ◽  
TING HUANG ◽  
SHU-DA YANG ◽  
LI-PING TANG
Keyword(s):  
New Species ◽  
Southwest China ◽  
Molecular Data ◽  
Southwestern China ◽  
A New Species

Gerhardtia yunnanensis is described as a new species from southwestern China. The species is characterized by its medium to large basidiomata with a yellow-brown to reddish brown pileus with a translucent-striate pale margin, weakly curved stipe, basidia with both cyanophilic and siderophilic reactions, basidiospore walls having a cyanophilic reaction, basidiospores with minute granular or verruculose ornamentation under SEM, narrowly clavate to irregular or curved clavate cheilocystidia and pleurocystidia, and absence of clamp connections. A comparison of all taxa of the genus was performed based on morphological and ITS and LSU molecular data. Furthermore, we provide a key to the known species of Gerhardtia worldwide.

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