Ordovician - Science topic

Specimens of the rugose coral Streptelasma? sp. are found intergrown with a host bryozoan Oanduellina bella in the lower Katian of Estonia. Rugosa also occur in the bryozoan Proavella proava. This is the earliest and only known record of endobiotic rugose symbionts in cryptostome bryozoans from the Late Ordovician of Baltica. The erect bryozoan col...

The Austroalpine Ötztal Nappe and the adjacent Marlengo Slice comprise pre-Variscan basement of Neoproterozoic to Early Paleozoic metasedimentary rocks intruded by Ordovician granitoids now present as orthogneisses. LA-ICPMS U-Pb zircon dating complemented by whole-rock geochemistry on orthogneisses from the Texelgruppe, the southeastern part of th...

Continent formation and its stabilization are key factors for understanding tectonic processes and histories across geologic time. Sri Lanka consists of a Central Highland (HC) granulite/UHT terrane bounded by tectonic sutures and medium-to-high-grade magmatic arc terranes likely formed via Neoproterozoic double-sided subduction and collision assoc...

The Antigonish Highlands form part of Avalonia in mainland Nova Scotia and are predominantly underlain by ca. 620-600 Ma low grade Neoproterozoic arc-related volcanic and sedimentary rocks and coeval plutons. The highlands also preserve a record of magmatism that spans much of the Ordovician (ca. 495-455 Ma), during which time Avalonia drifted from...

Trace fossils are described for the first time from the Purpurberg Quartzite of the Weesenstein Group, where deposition is so far considered to be glacio-eustatic controlled during the ∼565 Ma-old Weesenstein–Orellana glaciation. The mineralogically mature quartzites are locally rich in trace fossils, but the bedding plane bioturbation index is com...

Reflection seismic data were acquired in the Sudret area of Gotland between the 6th and 13th of November, 2023. Objectives of the survey were to obtain images of the subsurface down to the Precambrian basement in the vicinity of two cored boreholes that had been drilled earlier down to about 800 m. The seismic profiles were positioned to provide a...

A low-diversity, relatively well-preserved brachiopod fauna is documented in detail for the first time from the Sandbian-Katian (Upper Ordovician) siliciclastic rocks of the Oxhe Inlier (Belgium), i.e. a small Caledonian inlier included in the Condroz Inlier, whereas some preliminary data are also presented for the Darriwilian-Sandbian (Middle-Uppe...

Over the last 50 years, paleobiology has made great strides in illuminating organisms and ecosystems in deep time through study of the often-curious nature of the fossil record itself. Among fossil deposits, none are as enigmatic or as important to our understanding of the history of life as Konservat-Lagerstätten, deposits that preserve soft-bodie...

The Junggar Basin basement comprises microcontinental blocks amalgamated through successive paleo-oceanic accretion events. Stratigraphic and provenance studies within the basin are crucial for reconstructing its evolution and understanding the closure of paleo-oceanic systems. This study presents an integrated petrographic and geochemical analysis...

The Ordovician to Devonian strata of the Setul Group in the northern region of Peninsular Malaysia represents medium- to thick-bedded, white to grayish limestone rich in biota components. A detailed study of microfacies analysis and diagenetic investigation revealed eleven microfacies and five diagenetic histories. The recognized microfacies includ...

The Early Paleozoic porphyry-epithermal Au system of the Songshunangou district sits in the central segment of the North Qilian orogenic belt (NQOB). The porphyry Au mineralization is centered on the quartz diorite porphyry (QDP), which is constrained to the Late Ordovician period. However, the geochemical signatures, the origin, and the tectonic s...

Due to an unclear understanding of the crack initiation mechanism during the process of splitting grouting at the top of the Ordovician limestone, there is a lack of a theoretical basis for the selection of key parameters such as grouting pressure, slurry water–cement ratio, and borehole azimuth. This study explored those problems using indoor phys...

Understanding how marine organisms move in the water column is critical for comprehending their palaeoecology and palaeobiogeography. However, interpreting the locomotion of extinct invertebrates can be problematic and difficult because of the lack of close modern analogues or preserved soft tissues. In this study, we chose a biostratigraphically i...

The formation and evolution of carbonate weathering crust-type reservoirs are closely linked to paleokarst processes. This study aims to restore and analyze the karst paleogeomorphology and sedimentary environment of the Ma2 and Ma3 sections in the eastern Ordos Basin, using the compensation thickness impression method. The Ma3 section is character...

A revision of more than 660 specimens of fossil cephalopods from the Vormsi–Pirgu regional stages (late Katian Stage), Ordovician Period, of Estonia, available from the Estonian palaeontological collections, reveals the extraordinarily high cephalopod-richness of this interval, termed “Lyckholm acme of cephalopods” herein. Ninety species can be dis...

Deciphering the dolomitization process has great significance for high-quality hydrocarbon reservoir prediction in carbonate successions. The Ordovician Wulalike Formation provides shale oil in the western Ordos Basin, while lateral-contact marine dolostones of Kelimoli Formation contribute major reservoirs for extra hydrocarbons. Nonetheless, the...

We document newly recognised Late Ordovician high-pressure (HP) metamorphism in the Scottish Caledonides. Garnet growth at ca. 455–445 Ma within metabasic rocks from the Ross of Mull is constrained to pressures >0.9 GPa and was associated with formation of kyanite-bearing assemblages in meta-pelites that equilibrated at peak conditions of 1.0–1.2 G...

We present a refined global Furongian (late Cambrian) time scale derived through the application of Bayesian age modeling, using an integrative assemblage of conditioning likelihoods (age constraints) including U-Pb zircon maximum depositional ages in the Steptoean positive isotopic carbon excursion (SPICE) reference section in Smithfield Canyon (U...

The growth and evolution of the Eurasian continent involved the progressive closure of major ocean basins during the Phanerozoic, including the Tethyan and Paleo-Asian oceanic realms. Unraveling this complicated history requires interpreting multiple overprinted episodes of subduction-related magmatism and collisional orogeny, the products of which...

The Ordovician/Silurian boundary (Wufeng/Longmaxi formations) in the Shizhu region, eastern Sichuan Basin, China hosts organic-rich black shales which are frequently interbedded with bentonite and hydrothermal minerals (e.g., pyrite). This study investigated the mineralogical, total organic carbon (TOC), total sulfur (TS), and major and trace eleme...

The Ordovician fractured-vuggy carbonate reservoirs in China’s Tarim Basin are characterized by ultra-deep burial (>5000 m) and significant vertical-lateral heterogeneity. Such geological complexity severely degrades seismic data quality, manifesting as low signal-to-noise ratios (S/N) and limited resolution, thereby challenging accurate reservoir...

Metasomatism is a ubiquitous process in the Earth’s crust, exerting major controls on fluid, heat and mass transfer and rock deformation, and is commonly constituted by mineral replacement reactions. Different types of metasomatism may coexist and/or successively conceal each other in a given area. Deciphering the geochemical behaviour, regional ex...

The Middle Ordovician Duwibong Formation of the Sino-Korean Block records carbonate platform evolution during the middle Darriwilian (Middle Ordovician), a key interval associated with the Great Ordovician Biodiversification Event (GOBE). Detailed microfacies analysis of three measured sections (Hyeoldong, Sorotgol, and Seokgaejae) identifies seven...

The Earth's continental crust is predominantly composed of granitic rocks, yet the genesis of pure sediment-derived peraluminous granites (PGs) remains debated. This study investigates the Ordovician Mansehra granitic suite (ca. 476–483 Ma) from the northwestern Himalayas of Pakistan as an example of S-type granites, comparing them with global coun...

Elegantilites custos sp. n., a rare new hyolithid species is described from the late Middle to early Late Ordovician Dobrotivá Formation of the Prague Basin in the Barrandian area of the Czech Republic. The new taxon is based on excellently preserved external and internal moulds of three opercula and several conchs, collected from siliceous nodules...

As shallow coal resources in China become increasingly depleted, deep coal mining in complex geological areas has become an inevitable trend. However, the technical challenges associated with deep mining are becoming more significant, particularly the issues related to mine water hazards. This study utilized hydrogeological data from the III3 Minin...

The south margin of Central Altyn (SMCA) has long been considered as Precambrian stratigraphic unit of the Altyn Orogen. However, their strata attribution is subjected to challenge by the new finding of Siluran-Devonian metamorphic rocks. Aiming to further understand the geological evolution of the SMCA and its relations with the adjacent tectonic...

The change of paleoenvironment is an important factor affecting the change of hydrocarbon-forming organisms and the preservation of organic matter. Combined with global environmental changes, the study of Ordovician paleoenvironment in Ordos Basin is of great significance to guide oil and gas exploration. Taking the marine carbonate rocks of the Mi...

The term Ordovician, comes from the name of the Celtic tribe "the Ordovices" in the nineteenth century, when Charles Lapworth used it to designate a stratigraphic sequence in north Wales. The Ordovician is the second of six geological periods during the Paleozoic era that began 488.3 ± 1.7 million years ago and ended 443.7 ± 1.5 million years. It f...

We investigated mafic igneous rocks found in the vicinity of the allochthonous Münchberg Massif in the Saxo-Thuringian Zone of the European Variscides, NE Bavaria. The basaltic magmas were injected during the Ordovician, Silurian and Devonian into contemporaneous marine sedimentary rocks of the Saxo-Thuringian Basin. Ordovician sills east and Devon...

Lower Paleozoic continental margin rocks of the North American Cordillera, from Yukon to Nevada, include coeval platformal carbonate and basinal clastic strata that are offset along rift‐transfer faults, including the Liard, St. Mary‐Moyie, and Snake River structures. The Dawson fault is a prominent east‐west‐striking structure in central Yukon tha...

Revision of the type species of the Early Ordovician (Tulean, late Tremadocian) bathyurid trilobite Licnocephala Ross, 1951 demonstrates that it has significantly different morphology than that ascribed to it in the earlier literature, which was based largely on species now assigned to a different genus. In addition to the type species, L. bicornut...

Deciphering the evolution of spatial geometry of carbonate platforms in deeply buried successions is still a challenge due to the low resolution of seismic data and the constraints of drilling wells. In this study, by combining a seismic forward model, we systematically delineated the external morphology and internal architecture of seismic reflect...

Greywackes make up a substantial part of the Cadomian basement of Saxo-Thuringia. Here, their classification as greywackes and the timing of metamorphic overprint are re-evaluated using a multi-method approach. Immature monotonous greywacke sequences from the Lausitz (Lausitz Block) and Leipzig groups (North Saxon Anticline), as well as from the ea...

ABSTRACT This study presents a comprehensive geomechanical modeling of the naturally fractured Paleozoic reservoirs of the Hassi D’Zabat field, Algeria, to assess the in-situ stress state and critically stressed fractures. The Cambrian and Ordovician reservoirs exhibit vertical to sub-vertical open to partially open fractures, as interpreted from t...

The plectorthoid brachiopod Kvania is widely distributed in Upper Cambrian and Lower Ordovician rocks of the Central Andean basin of northwestern Argentina and southwestern Bolivia. In this contribution, Kvania lariensis Benedetto is reported for the first time in the Eastern Cordillera (Quebrada de Humahuaca area) of northwestern Argentina. Studie...

The Ordovician carbonate formations in the Ordos Basin provide a crucial stratigraphic unit for prospective oil and gas exploration. Significant progress has been made in the exploration of natural gas within the Ordovician subsalt formations. Nonetheless, understanding its accumulating properties requires additional investigation. Clarifying the f...

The post-impact fauna of the Dalby Limestone of Tvären Bay has been extensively examined, with the exception of the Palaeostomate bryozoan taxa present. Here, we report three palaeostomate bryozoans found in limestone boulders recovered from glacial deposits on Ringsö Island derived from Tvären Bay, Sweden. The bryozoan fauna includes Pachydictya b...

The characterization of carbonate microstructure is of great significance for the evaluation of carbonate oil and gas resources. However, due to the complexity and heterogeneity of the pore structure of tight carbonate rocks, high-pressure mercury intrusion, nuclear magnetic resonance (NMR) and other methods have different limitations in the charac...

An ostracod assemblage from the Late Ordovician (Katian) Phu Ngu Formation of northern Vietnam, South China paleoplate, yields typical Baltic and Laurentian-­ affinity genera together with some endemic forms. Detailed paleontological and sedimentary analysis of the Phu Ngu Formation suggests it was deposited in a deeper marine forearc setting, belo...

Sponges (phylum Porifera) have been essential to marine ecosystems for over 600 million years, contributing to nutrient cycling, reef building, and ecological stability. Despite their evolutionary importance, the drivers of their diversity dynamics remain poorly understood. This study investigates the diversification patterns of Demospongiae, the l...

In New Jersey and New York, the continued tectonic plate motion of perpetual slow drift of the North American Plate (NAP) hold residual compressive stresses on Mesozoic and Paleozoic fault systems. Focused seismicity occurs where of Ordovician Plutons in New York resist crustal drift due to pinning the crust to the asthenosphere (Herman, 2015, 2022...

Reservoir space characteristics are the key to reservoir evaluation and the evaluation of reservoir capacity. The reservoir space of fracture-vuggy carbonate reservoirs is complex and diverse, and it develops from micro to macro. There is a lack of systematic study on the reservoir space of the Ordovician fracture-vuggy carbonate reservoir. Therefo...

Neosho County has an area of 576 square miles and is within the Osage Plains section of the Central Lowlands province of eastern Kansas. Sedimentary rocks of Cambrian, Ordovician, Devonian(?), Mississippian, Pennsylvanian, Tertiary, and Quaternary ages overlie the Precambrian basement complex, and they have a thickness of 2,100 feet. Rocks exposed...

This contribution illustrates the scientific significance of materials kept in the Early Paleozoic section of the collections of the Museum of Bohemian Karst in Beroun. Two samples from the historical collection of Professor Celda Klouček are analyzed and described in this brief study. The first sample is a well-preserved internal mold of an incomp...

The occurrence of intrusive rocks within the Xinlin area, northeastern China, provides insights into the Neoproterozoic–Mesozoic geodynamic setting of the Erguna block. In this study, we present petrographic, geochemical, and geochronological data on intrusive rocks from the Xinlin area. Zircon U–Pb and muscovite ⁴⁰Ar/³⁹Ar geochronology reveal that...

Linn County is located along the Kansas-Missouri boundary in east-central Kansas and is a nearly square area of about 605 square miles. The relief in this area is moderate, and the topography is characterized by northeast-trending cuestas that face southeast. The county is located mostly within the Marais des Cygnes River drainage basin and contain...

The map reflects Peninsular Malaysia's complex geologic evolution, including the closure of the Paleo-Tethys ocean, continental collisions, and subsequent magmatic and metamorphic events. Below is a detailed explanation based on the features visible in the map: Key features include (a)Tectonic Belts- the western, central, and eastern belts, which a...

A ventral valve of the small lingulate brachiopod Orbithele ceratopygarum (B , 1882) is described from a geschiebe (glacial erratic boulder) of the Ceratopyge Limestone (Lower Ordovician, Tremadoc). The geschiebe was found in a gravel pit of the Laer-heide area (County of Osnabrück, NW-Germany). In addition, some remarks are made concerning the str...

The FⅠ17 fault is a prominent strike-slip fault in the central Tarim basin, notable for its hydrocarbon abundance and intricate tectonic attributes, characterized by several deflections in its planar trajectory. Analyzing the FⅠ17 fault offers crucial insights into the role of basement structures on the evolution and formation of intracratonic stri...

Deep oil reservoirs are becoming increasingly significant fields of hydrocarbon exploration in recent decades. Hydrothermal fluid flow is deemed as a potentially crucial factor affecting the occurrence of deep oil reservoirs, such as enhancing porosity/permeability of reservoirs, accelerating oil generation and thermal cracking, and modifying organ...

In the risk assessment of water inrush from coal floors, the amount of measured data obtained through on-site testing is small and random, which limits the prediction accuracy and generalizability of a model based on measured data. Using the distribution characteristics of the measured data and mega-trend diffusion theory, we propose a virtual samp...

Glendonites (from the precursor of ikaite, CaCO3.6H2O) preferentially precipitate within sediments in cold waters (− 2 to 7°C) via either organotrophic or methanogenic sulphate reduction. Here, we report the first occurrence of possible glendonites associated with the end Permian mass extinction in the earliest Triassic (ca. 252 Million years ago,...

Two species of the genus Heliomera RAYMOND, 1905, the new Heliomera borealis n. sp. and Heliomera parvulobata SCHÖNING, 1994 are described from four Middle Ordovician glacial erratics, found in the area of the outer Kieler Förde (Schleswig-Holstein, Northern Germany). Three glacial erratics can be attributed to the Kunda stage (lower Darriwilian) o...

From glacial erratics 2 cranidia of rare trilobite taxa of the Baltoscandian Ordovician are described. They were found in the gravel-sand ridge of the Laerheide (county of Osnabrück, northern Germany). Cybelurus sp. comes from a glacial erratic probably belonging to the Lower Red Orthoceratite Limestone, Hunneberg to Volkhov stage (uppermost Tremad...

After two pulses of mass extinction during the Late Ordovician, a continuous rise in sea level led to the formation of anoxic black shale deposits in deep-water areas in various regions of the world. These deposits usually contain only graptolite fossil assemblages. The discovery of sponge-dominated assemblages in graptolitic shale of the Ordovicia...

From the Saalian glacial deposit of the Laerheide (county of Osnabrück, NW-Germany) 620 glacial erratic boulders are investigated on their trilobite remains. The boulders originate from the Ordovician of Baltoscandia. Many of them mostly consisting of different kinds of carbonates are assigned to 16 various typs of glacial erratics. Exoskeletal rem...

Bioclaustrations are extremely rare in the rugose corals from the Ordovician of Estonia. A specimen of Kenophyllum subcylindricum from the Vormsi Regional Stage (Katian) contains multiple shafts of Chaetosalpinx siberiensis?. The latter bioclaustration also occurs in the Pirgu Regional Stage (Katian). The growth lines of the host coral show a react...

The temporal range of eodiscids and agnostoid arthropods overlaps with several early Paleozoic geological events of evolutionary significance. However, the responses of agnostids to these events and how the perturbations associated with them (both abiotic and/or biotic) may have impacted agnostids remain uncertain. To address this uncertainty, we e...

Drylands, which comprise ~45% of Earth's land area, host biological soil crusts (biocrusts)-symbiotic communities of cyanobacteria, fungi, algae, lichen, and bryophytes that stabilize soil and support key ecosystem functions. Moss dominated biocrusts in particular are interesting due to their potential to illuminate ancient bryophyte-fungal interac...

Several levels of the Lorraine Group (Upper Ordovician) in upstate New York (USA) have yielded low-diversity, exceptionally preserved, pyritized invertebrate assemblages dominated by the trilobite Triarthrus eatoni. Sedimentological and taphonomic features suggest dysoxic bottom-water conditions, with limited transport and rapid burial by distal tu...

In this paper, we present the new results of the U–Pb age dating and Lu-Hf isotopic analysis of detrital zircons of the four representative metasedimentary rock samples from the Mongol Altai Group, Mongolian part of the Altai-Mongolian terrane. Our new results indicate that the metasedimentary rocks of the Mongol Altai Group were formed after ∼497...

The phosphate-bearing rocks (phosphate rocks and phosphorites) were studied over a 45-meter interval of the Moyero river section, covering the upper part of the Darriwilian and the lower part of the Sandbian stages of the Ordovician. These rocks were investigated by field observations and laboratory methods, including optic and scanning electron mi...

Interpretation of geological and geophysical data covering the structure of the South Kara depression suggests that deep salt cryptodiapirs are involved in its structure. They are large-amplitude (up to 10 km) isometric columnar-shaped salt stocks separated by deep minibasins, involving halokinetic sequences (growth strata). Analysis of the regiona...

Retene and dehydroabietic acid methyl ester (DAME) are biomarkers linked mostly to terrigenous organic matter. However, their aquatic origin from algae and/or cyanobacteria has been discussed in the past few years. The complex origin of retene and DAME can lead to misinterpretation during biomarker interpretation, which can be minimalised with the...

Cheiruridae is one of the most diverse families of trilobites known from the Ordovician with 453 species assigned. Within Cheiruridae eight subfamilies (Acanthoparyphinae, Cheirurinae, “Cyrtometopinae”, Deiphoninae, Eccoptochilinae, Heliomerinae, Pilekiinae, and Sphaerexochinae) have historically been recognised. Insights about the evolution of the...

Geological borehole 4310_02W at Valy nad Labem yielded 145 meters of the core that sampled Upper Cenomanian to Middle Turonian sediments of the Bohemian Cretaceous Basin. These sediments are represented by the Peruc–Korycany, Bílá Hora and Jizera Formations, overlaying the metamorphosed Ordovician basement. Here we describe in detail distinct litho...

Caryocaridids exhibited a wide geographical distribution and high diversity during the Great Ordovician Biodiversification Event. The global geographical distribution, limited taxonomic examination and lack of insight into preservational conditions have collectively contributed to an inadequate systematic assessment of Ordovician caryocaridids. To...

The Durness Group of NW Scotland records deposition on the Laurentian margin from the basal Miaolingian (Cambrian, 509 Ma) to the Dapingian–Darriwilian boundary interval (Middle Ordovician, 470.3–468.9 Ma). The 930 m thick succession of peritidal and subtidal carbonates was deposited on the Scottish promontory, a nearly 120° deflection in the Palae...

The well-preserved Llandovery (lower Silurian) succession of Anticosti Island (Quebec, eastern Canada) contains an expanded Aeronian–Telychian boundary interval when compared to other coeval basins. This boundary interval on Anticosti Island also includes two of the most important Llandovery biogeochemical events, the late Aeronian and Valgu events...

The existence of Ordovician Peruvian cephalopods has been known since at least the 1910s. However, they have not been effectively documented previously with only a few described taxa listed in open nomenclature. Here, we describe a cephalopod assemblage at the finest taxonomic level possible. The specimens were collected from the Floian section ( B...

The recovery of reservoir paleo-pressure has been a key focus in hydrocarbon accumulation research. The evolution of paleo-pressure in carbonate reservoir rocks has long been a research challenge for researchers. Using the Tahe area in the Tarim Basin as a case study, this paper proposes an idea for studying the paleo-pressure evolution in carbonat...

Understanding the relationship between faults and underground rivers is crucial for oil and gas exploration. The presence of faults in the Ordovician carbonate rocks plays a significant role in the formation of fracture-cave reservoirs in the Tahe Oilfield that located in Tarim Basin, Northwestern China. In this research, faults analysis and thorou...

During the Late Ordovician period, changes in climate and mass extinctions were observed; however, the factors influencing these phenomena have not been fully understood. In order to understand the relationships among redox water conditions, climates, and mass extinctions in the Late Ordovician, this study analyzes the chemical index of alteration...

In the upper part of the Dzheromo Formation (Dolborian Regional Stage, Katian Stage, the Upper Ordovician) along the Moyerokan River (Northern Siberian Platform) seventeen bryozoan species were revealed, seven from which, due to the poor preservation of the colonies, were identified in an open nomenclature. The bryozoans belong to 10 genera from fo...

The Sirman Formation in the Svoge Unit is built of Hirnantian diamictites, a product of the Gondwana glaciation at the end of the Ordovician. One subangular lonestone of light gray sandstone of size of about 1 cm was found in the lower part of the formation. This pebble, interpreted as a glacial dropstone, contain a relatively well-preserved extern...

We use 3-D seismic data from an unnamed oilfield to characterize the internal architecture, structure, and porosity and permeability distributions in ultra-deep (> 6 km) Cambro-Ordovician carbonate reservoir strata deposited on a long-lived, regionally extensive carbonate platform in the Tarim Basin, northwest China. These strata comprise three dom...

Trace fossils preserved with fossil worm-shaped remains suggest the presence of free-living flatworms during the Ordovician at the latest and their occurrence in terrestrial environments during the Permian. The presence of hooks associated with acanthodian and placoderm fishes indicates the existence of parasitic monopisthocotyleans, with a simple...

Accurate dating of terrestrial impact structures provides important insights for the evolution of life, with impacts often being associated with biological disturbances and climatic changes. This study investigates the Gosses bluff impact structure in central Australia to confirm the debated age of the structure. Materials were sourced from histori...

The Ordovician dolomite in the Ordos Basin is an important natural gas reservoir. Exploring dolomite genesis and the factors influencing reservoir characteristics is essential for deep carbonate rock exploration. This study offers a comprehensive analysis of dolomite evolution using methods such as thin-section petrography, isotope analysis, and tr...

The Upper Ordovician (Katian) Neda Formation, a phosphatic ironstone, records a widespread but short‐lived shift to ferruginous waters across a vast epicontinental area. Lithofacies and stratigraphic reappraisal indicate that Neda ironstone deposition occurred on a storm‐dominated ramp when coastal upwelling emplaced eutrophic ferruginous waters th...

Throughout the Earth's history, the extinct and extant organisms have played and still play a major role in building and shaping the geological record. Both micro- and macroorganisms can drive biomineralization, i.e., the processes by which minerals are deposited in the biological matrix of living organisms, or can mediate geochemical and mineraliz...

In a classic study of bivalves from the Upper Ordovician (Katian) Boda Limestone, Sweden, Isberg (1934) named and described 18 species of the unusual bivalve Shaninopsis, all from the same locality. Our study of the type material indicates that only three species at most are present: Shaninopsis prona Isberg, 1934, Shaninopsis radiata Isberg, 1934,...

Triarthrus novoaustralis, a new species of olenid trilobite, is described from the Malachis Hill Formation (mid-Katian, Late Ordovician) near Keenans Bridge and Canobolas State Forest, west of Orange, New South Wales, Australia. This is the second named (and youngest) olenid occurrence from the entire Ordovician of eastern Gondwana. Additionally, i...

Introduction Arc-continent collision contributes to the accretion of continental crust in the Central Asian Orogenic Belt. The Chegendalai ophiolitic mélange, located between the Bainaimiao arc and the North China Craton, is important to understanding the early Paleozoic evolution of the South Bainaimiao Ocean and arc-continent collision processes....

Fracture is a key factor for high and stable reservoir production in Ordovician carbonatite fracture-cavity reservoirs in the Tahe Oilfield. In this paper, we firstly identify and statistically analyse the medium to small scale fractures in the Ordovician carbonate reservoirs of the Tarim Basin Tahe Oilfield by using a large amount of thin section,...