Science topic

Ordovician - Science topic

Explore the latest publications in Ordovician, and find Ordovician experts.
Filters
All publications are displayed by default. Use this filter to view only publications with full-texts.
Publications related to Ordovician (10,000)
Sorted by most recent
Article
Full-text available
The Ordovician global cooling trend observed by several temperature proxies, which coincides with one of the most significant evolutionary diversifications on Earth, is yet to be fully understood. This study presents new simulations of pCO2 and surface temperatures using a spatially resolved climate-carbon cycle Earth system model fed with refined...
Article
Full-text available
Strike-slip faults developed in the middle lower Ordovician carbonate formation in the T-SH area of Tarim Basin play an important role in controlling the migration and accumulation of hydrocarbon. The reservoir in the study area is reformed by multi-period fluid, and the influence of different component fluid on different positions of fault is of g...
Article
Full-text available
Since the onset of plate tectonics, continents have evolved through a balance between crustal growth, reworking, and recycling at convergent plate margins. The term “reworking” involves the re-insertion of crustal material into pre-existing crustal volumes, while crustal growth and recycling respectively represent gains from and losses to the mantl...
Article
Full-text available
Strongly deformed footwall rocks exposed in metamorphic core complexes (MCC) of the North American Cordillera were exhumed via ductile attenuation, mylonitic shearing, and detachment faulting. Whether these structures accommodated diapiric upwelling or regional extension via low-angle normal faulting is debated. The Ruby Mountains-East Humboldt Ran...
Article
Full-text available
This study is the first detailed investigation of the tectono-stratigraphy, regional structure and mesoscopic fractures of the Zagros fold-thrust belt in the Duhok region, Kurdistan, Northern Iraq, and is based on field studies, remote sensing-GIS analyses, cross-section restorations, and tectonic analysis of key structures. The Duhok fold belt is...
Article
Full-text available
Earth’s long-term climate may have profoundly influenced plant evolution. Local climatic factors, including water availability, light, and temperature, play a key role in plant physiology and growth, and have fluctuated substantially over geological time. However, the impact of these key climate variables on global plant biomass across the Phaneroz...
Article
Full-text available
Although pre-stack inversion has been carried out on reservoir prediction, few studies have focused on the application of pre-stack for seismic inversion in fractured-cavity carbonate reservoirs. In carbonate rock, complicated combinations and fluid predictions in karst caves are remain unclear. Post-stack methods are commonly used to predict the p...
Conference Paper
Full-text available
Gastropoda experienced many major shifts in its evolutionary history including extinction of most of the early groups, survival of a few, and radiation of novel groups. Pleurotomariida (slit shells) is one of the most ancient gastropod groups and has the longest fossil record among living gastropods. It can be traced back to the Cambrian–Ordovician...
Article
Full-text available
The Ordovician–Silurian transition was a critical period in geological history, during which profound changes in climatic, biotic, and oceanic conditions occurred. To explore the provenance, palaeoclimate, and palaeoredox conditions in the Sichuan Basin during the Late Ordovician–early Silurian interval, we conducted mineralogical, geochemical, and...
Article
Full-text available
The mining depth of most coal mines in North China has exceeded 1 km. The high seepage water pressure caused by high ground stress leads to the increasingly serious threat of water disaster in the mine. To explore the relationship and mechanism between water inrush from deep mining floor and grouting prevention, single-level grouting and multi-leve...
Article
Full-text available
The second most severe extinction event that hit the Earth biosphere was the end Ordovician great extinction that erased 57% of the extant marine animal genera. The cause of that extinction was considered for long time the Hirnantian glacial period, however the evidence of the glaciation were rather consequences than evidence of the great extinctio...
Article
Full-text available
As a key step of the Wilson cycle, subduction initiation is regarded as a start hallmark of the ocean-continent transformation. However, the crust-mantle interaction and crustal growth processes related to subduction initiation remain enigmatic. Here we report a newly recognized complete magmatic sequence containing three rock assemblages in the Ho...
Conference Paper
Full-text available
Fossils of cephalopods are ubiquitous in collections and museum exhibitions, with belemnites and ammonoids being particularly well represented. This has led to a strong research interest in these taxa and our knowledge on them has accordingly grown considerably in recent decades. In contrast, the earliest fossil cephalopods - informally called "nau...
Article
Full-text available
The deep coal mining in the North China type of coalfield is generally threatened by the underlying limestone water of Taiyuan Formation and Ordovician. The occurrence of water inrush can be avoided effectively by applying grouting reinforcement technology to the coal floor. However, the reinforcement treatment of the coal floor belongs to undergro...
Article
Full-text available
The distribution of gold in biogenic apatites from the Ordovician deposits in the northwest of the East European Platform shows that the maximum concentration of gold in apatites is found within the Ladoga-Baltic suture zone. Gold mineralization has a superimposed character, which is confirmed by the dependence of the gold content on the size of ap...
Article
Full-text available
The Truong Son orogenic belt (TSOB) is one of the most important orogenic belts in the Indochina block. There are numerous mafic to felsic intrusions in the Early Paleozoic caused by the Tethyan orogeny. However, the tectono-magmatic evolution of the TSOB in the Early Paleozoic is still unclear. In this paper, zircon U-Pb dating, whole-rock geochem...
Article
Full-text available
The marine shale of the Upper Ordovician Wufeng Formation–Lower Silurian Longmaxi Formation is the main source rock and the target of shale gas exploration in the southern Sichuan Basin. The maturity of organic matter (OM) is a vital indicator for source rock evaluation. Due to the lack of vitrinite, the organic matter maturity of the Wufeng–Longma...
Article
Full-text available
The closure time of the Shangdan Ocean is critical for understanding the tectonic evolution of the Proto-Tethys Ocean. However, the proposed closure time was prolonged from Ordovician to Devonian. In the present study, detrital zircon from the metasedimentary rocks of the Liba Group in the West Qinling Belt was analyzed to constrain the closure tim...
Article
Full-text available
The pre-Alpine Marmarosh Massif is a tectonically complex unit of the crystalline basement within the Eastern Outer Car-pathians. In the eastern (Ukrainian) segment of this massif, two units have been identified-the Bilyi Potok Nappe and the Dilove Nappe. Petrological investigations coupled with zircon U-Pb dating were performed on metavolcanic roc...
Article
Full-text available
The mining engineer Primitivo Hernández-Sampelayo was one of the most relevant figures in the study of the Spanish Paleozoic since Lucas Mallada’s time. After a few years working in mining companies, he entered the Geological and Mining Institute of Spain in 1914, where he worked until his retirement in 1950. The results of his studies are the larg...
Article
Full-text available
The Ordovician Lagerstätten record substantial amounts of excellent preservation and soft-bodied fossils during the Great Ordovician Biodiversification Event (GOBE). However, few Lagerstätten are known from the Lower Ordovician, most of which are preserved in restricted environments and high-latitude regions. Here, we report on a new tropical Lager...
Article
Full-text available
We describe the first occurrence of diamond-facies ultrahigh pressure metamorphism along the Gondwana-Pacific margin of the Terra Australis Orogen. Metamorphic garnet grains from Ordovician metasediments along the Clarke River Fault in northeastern Queensland contain inclusions of diamond and quartz after coesite, as well as exsolution lamellae of...
Article
Full-text available
The conodont fauna from the Daduhe Formation in southwestern Sichuan and northeastern Yunnan, southwestern China, is analyzed and correlated with the uppermost Ordovician Amorphognathus ordovicicus conodont Biozone. This age assignment is further supported by the graptolites from the same sections, indicating a Ka4 Stage Slice, i.e., from the Dicel...
Conference Paper
Full-text available
The age of evaporitic units in the Kidson Sub-basin of the Canning Basin have been assigned to be of Late Ordovician to Early Silurian age through the dating of the sedimentary sequences within the Mallowa Salt. The Frome Rocks 1 exploration well was drilled in 1959 on the Jurgurra Terrace on the southern margin of the Fitzroy Trough and enco...
Thesis
Full-text available
Gastropoda are one of the most diverse living animal group and show an almost steady increase in diversity since their origination in the Cambrian. However, not all gastropod groups underwent this continuous diversification. Many groups became either extinct or decreased in diversity significantly during the evolutionary history of Gastropoda. Unde...
Article
Full-text available
New data are given on zonal graptolite units in the structure of the new Ordovician stage standard within the framework of the International Stratigraphic Chart. Ordovician zonal graptolite successions in the largest regions of Russia have been analyzed and correlated. Научные дискуссии о независимом параллельном или взаимодополняющем (взаимозаменя...
Article
Full-text available
This paper reports new geochronological data on metagranitoids (U-Pb SIMS) and ophiolites (Sm-Nd) from the Khanka massif. New and published data define the Early Neoproterozoic Matveevka-Nakhimovka terrane with 935-and 915-Ma early suprasubduction magmatism, 850-880-Ma and 757-Ma withinplate and Pacific-type transform margin magmatism, as well as t...
Article
Full-text available
As an important oil and gas-bearing area in the Tarim Basin, the Halahatang Area has great potential for resource exploration. However, the research on oil and gas sources and the filling period of the Lower Paleozoic Ordovician is still limited. In this study, the organic geochemical analysis of source rocks, the simulation technology of hydrocarb...
Article
Full-text available
The Late Ordovician mass extinction (LOME), the second-largest biodiversity crisis of the Phanerozoic, occurred in two discrete pulses, the causation of both of which has been linked to environmental stresses induced by the onset and termination of the Hirnantian Glaciation. Recent studies have inferred significant mercury (Hg) anomalies, mainly fr...
Article
Full-text available
This paper reports new geochronological data on metagranitoids (U-Pb SIMS) and ophiolites (Sm-Nd) from the Khanka massif. New and published data define the Early Neoproterozoic Matveevka-Nakhimovka terrane with 935-and 915-Ma early suprasubduction magmatism, 850-880-Ma and 757-Ma withinplate and Pacific-type transform margin magmatism, as well as t...
Article
Full-text available
Soil Se level and its influencing factors are significant for local human health, the scientific use of land, and the development of characteristic agriculture. The soils in Lanshan District were sampled, and the influencing factors and enrichment model of soil Se were discussed. The soil Se levels are in the range of 0.01–10.8 μg/g, with an averag...
Article
Full-text available
The structural features of the continental shelf and oceanic basin of the Eastern Arctic as well as its tectonic history are particularly controversial. The New Siberian Islands (NSI) archipelago is one of the few territories accessible for direct geologic study in this region. The De Long Islands occupy the northernmost part of the NSI archipelago...
Conference Paper
Full-text available
We have developed and applied a laboratory routine protocol to determine in single zircon crystals both the U-Pb crystallization age and the (U-Th)/He age-that reflect the low-T history of the source formation. This, "U-Pb-He double dating" approach includes UV-laser extraction of He from a small volume of detrital zircon crystals (~30 µm ablation...
Poster
Full-text available
Zhen, Y.Y., Zhang, Y-D., Chen, Z-Y. & Wang, L-W., 2022. Origination of the ramiform—pectiniform apparatuses in conodonts — New evidence from the Lower Ordovician of South China and Australia. In: Chen, Y., Jiang, H-S. & Lai, X-L. (eds), Program and Abstracts, 2022 Pander Society Fifth International Conodont Symposium (ICOS5), p. 73.
Article
Full-text available
A third specimen of Megistaspis (Ekeraspis) cf. hammondi is described from the most important Ordovician Burgess Shale-type Fossil-Lagerstätte in Morocco. The trilobite specimens with soft-part preservation are located in late Tremadocian levels within the Fe�zouata Formation, but are very rare. The studied specimen preser�ves the right antenna,...
Article
Full-text available
During the sedimentary period of the Ordovician Yingshan Formation, the carbonate platform of the Gucheng area in the Tarim basin was characterized by a distally steepened ramp. Relative sea-level changes exerted a strong influence on the shoal facie dolomite reservoirs of the 3rd Member of the Ordovician Yingshan Formation (the Ying 3 member), sed...
Article
Full-text available
Dolostone is widely distributed and commonly used as concrete aggregates. A large number of studies have shown that there are significant differences in the expansibility of different dolostones, and the key factors determining the expansibility of alkali carbonate rocks have not been clarified. In this paper, rocks were selected from five differen...
Article
Full-text available
The Molla-Bismil area is a petroleum province, which hosts predominantly Paleozoic oil fields in the foreland area of the Diyarbakır Basin. The Arpatepe, Bahar, Yeniev, and Çalıktepe fields are Paleozoic oil field discoveries in the Molla-Bismil area to-date and have consequently been the focus of considerable research. This significant breakthroug...
Article
Full-text available
The paper presents petrographic, geochemical, and new U-Pb zircon (LA-ICP-MS) geochronological data on the Upper Lena Fm. sediments which make part of the Cambrian sedimentary cover of the Siberian craton. The composition of lithic fragments in these clastic sediments, including mafic and felsic volcanics and granitoids, along with the correlation...
Conference Paper
Full-text available
Regardless of the porosity of the matrix, fractures have a crucial role in increasing permeability. In this article, the critical role that natural fractures may play in enhancing fluid flow characteristics is considered. An attempt to demonstrate the contribution of fractures on enhancing the permeability was done, assuming the genetic relationshi...
Article
Full-text available
Mega-streamlined landforms on Earth and Mars have been attributed to aeolian, glaciogenic, fluvial, and tectonic processes. Identifying the forces that shaped these landforms is paramount for understanding landscape evolution and constraining paleo-climate models and ice sheet reconstructions. In Arabia, east-northeast trending, kilometer-scale str...
Article
Full-text available
In recent years, the Ordovician fault-controlled fracture-cavity reservoirs developed in the basement strike-slip fault zone in the Shunbei area of the Tarim Basin has achieved major breakthroughs. However, during the drilling process of the strike-slip fault zone in the Shunbei area, the problem of mud leakage in the frequently interbedded Siluria...
Article
Full-text available
The Risha field is one of the Jordan's most important gas fields, but little has been known about the origins and the underlying formation mechanism(s) of its gases. Hence, we carried out studies to determine the origin and formation mechanism of the natural gas in the Risha field, Jordan. The integrated carbon and hydrogen isotope compositions rev...
Article
Full-text available
Subduction zones provide important constraints on reconstruction of tectonic configurations and convergent geodynamics. The timing and evolution of the subduction zones at the interaction between the Paleo-Asian and Tethyan Oceans remain ambiguous, casting significant uncertainty on the reconstructions of proto-Asia and subduction dynamics. Here we...
Article
Full-text available
To understand the effect of thermochemical sulphate reduction (TSR) on the stable carbon isotopes of light hydrocarbons (LHs) associated with natural gas, 15 gases with varying H2S content from Ordovician reservoir of the Tazhong gas field (TZ-I) in Tarim Basin and Triassic Leikoupo reservoir of the Zhongba gas field (ZB) in Sichuan Basin were coll...
Article
Full-text available
Natural gases from the Taiyang (shallow), Jiaoshiba (middle), and Weirong (deep) shale gas fields in the southern Sichuan Basin were analyzed for molecular and stable carbon isotopic compositions to investigate the geochemical characteristics and gas origins. All the gases belong to shale gas from the Upper Ordovician–Lower Silurian shale and are d...
Article
Full-text available
In the upper basin of the Guadiana River, especially in the sectors drained by its right-bank tributaries, the Bullaque and Becea rivers, important concentrations of Acheulean and Mousterian industries can be found in a superficial position. These industries have provided series containing tens of thousands of pieces. Deposits in stratigraphic posi...
Article
Full-text available
The characteristics of lithofacies in the shale reservoir of the Wufeng and Longmaxi formations located in the Luzhou gas field were studied using the three-end-member method (mineralogical components). In addition, the microscopic characteristics and pore genesis of different lithofacies were studied and compared using TOC, FESEM, and digital core...
Article
Full-text available
China’s most successful horizon for shale-gas exploration and development is the Upper Ordovician Wufeng Formation through the Lower Silurian Longmaxi Formation in its Upper Yangtze Region. In this study, the Wufeng–Longmaxi Formation black shales in the Upper Yangtze Region are analysed to determine their microstructural characteristics, total org...
Article
Full-text available
Deformed vein systems may exhibit complex geometries with kinematics that are not always easily reconciled within the overall tectonic framework and interpreted palaeostress fields. In ore exploration and mining, the misinterpretation of complex vein geometries as polyphase deformation, as opposed to progressive deformation, may be detrimental to d...
Article
Full-text available
Recent studies revealed that the calc-alkaline metagranitoids of the Seckau Complex comprise both (1) a Late Cambrian to Early Ordovician and (2) a Late Devonian to Early Carboniferous (early Variscan) intrusive complex. The older rocks of the Hochreichart Plutonic Suite reflect I to S-type affinity and are peraluminous and characterized by a gener...
Article
Full-text available
The complex deformation styles of large intraplate strike-slip fault systems in the multi-stage superimposed basin are hot topics worldwide. This article proposes structural models and evolution processes for such strike-slip fault systems in the Tarim Basin based on high-resolution 3D seismic data and deep wells. Our analyses reveal that strike-sl...