Devonian Deposits Research Articles

Devonian–Carboniferous regional deformation in the northeastern Lachlan Orogen, southeastern Australia

The timing of regional deformation of the turbiditic Silurian–Devonian Hill End Trough in the northeastern Lachlan Orogen has been a contentious issue with one view ascribing the regional north–south folds and axial planar foliation to Middle Devonian basin inversion. Alternatively, it has been argued that given the low-angle discordance between Lower and Upper Devonian units on the Capertee and Molong highs, and the development of a dominant episode of folding mapped from the Hill End Trough into the adjoining highs, the major regional deformation is latest Devonian to early Carboniferous and predates intrusion of Bathurst-type granites at 358–314 Ma. We have approached the problem by analysing the gentle, upright, southeast-trending folds and deformation patterns in Devonian units of the northern Capertee High (Cudgegong area), drawing a cross-section across the Hill End Trough and reviewing the structure of two areas in the Molong High (west of Orange, and south of Wellington). Upper Devonian units on the highs are affected by fold patterns that extend into the underlying successions and have been interpreted as continuous into the central Hill End Trough, confirming the extent of the latest Devonian to early Carboniferous regional deformation in the northeastern Lachlan Orogen. Constraints from timing of deposition and radiometric ages are ambiguous and imply deformation was overlapping with sedimentation, as has also been inferred from sedimentary features of the Upper Devonian succession. Steeply dipping faults along the highs predated the Late Devonian and were probably formed in extension during formation of the Hill End Trough and were reactivated during basin inversion and potentially during Upper Devonian sedimentation. Our conclusion is that the simplest hypothesis is that the regional east–west shortening was of latest Devonian to early Carboniferous age, although poorly understood basin inversion occurred in the Middle to Late Devonian. KEY POINTS The timing of the development of regional north–south folds in the northeastern Lachlan Orogen has been a contentious issue and is difficult to resolve, given the broad stratigraphic constraints and ambiguous radiometric ages. The simplest hypothesis remains that the regional deformation was of latest Devonian to early Carboniferous timing. Middle to Late Devonian deformation included reactivation of basin-forming steeply dipping faults during basin inversion and ongoing sedimentation.

Biostratigraphy, biofacies, and palaeoecology of the Upper Devonian deposits (Khoshyeilagh Formation) based on conodonts in the northeast of Iran (around Bojnord and Jajarm)

Biostratigraphy, biofacies, and palaeoecology of the Upper Devonian deposits (Khoshyeilagh Formation) based on conodonts in the northeast of Iran (around Bojnord and Jajarm)

New Findings of Diamonds and Diamond Indicator Minerals in the Middle Timan and Prospects of the Search for Their Original Sources

In the poorly studied southeastern part of the Chetlas uplift, ring structures typical for magmatic pipe-type bodies (diatremes) have been established. The main part of the ring structures is located in the areas of the distribution of the Upper Devonian sediments. This fact indicates the lower age threshold of the formation of the objects forming them as Late Devonian, i.e., similar to the age of kimberlites of the Arkhangelsk diamond-bearing province. To assess the prospects of one of the most numerous groups of the ring structures, heavy-mineral concentrate sampling of the modern stream sediments was conducted. While studying the heavy-mineral concentrates, chromium-bearing pyrope—a kimberlite indicator mineral—was revealed, and the first diamond grain was found. About 20% of pyropes are characterized by a high preservation of relict endogenous surfaces. The diamond has the appearance of a flattened aggregate with the distinct octahedron faces modified by surfaces of joint growth with other mineral grains. Findings of diamonds and signs of the formation of the diamond indicator minerals in the stream sediments of the studied area make it possible to detect their nearby original sources.

О НАХОДКАХ ДУНКЛЕОСТЕИДНЫХ ПАНЦИРНЫХ РЫБ (PISCES, PLACODERMI) В ЕВРОПЕЙСКОЙ ЧАСТИ РОССИИ (ТЕРРИТОРИЯ ЦЕНТРАЛЬНОГО ДЕВОНСКОГО ПОЛЯ)

The Dunkleosteidae Stensiö family includes large predatory Paleozoic armour fishes. Their remains are rare in the Devonian deposits of the European part of Russia (Central Devonian field). The finds of both Eastmanosteus Obruchev and Dunkleosteus Lehman genus representatives and indefinte dunkleosteids were detected in the area. currently there is a collection of some dunkleosteid remains at the Earth Sciences Museum of Moscow State University. The materials were collected in two localities in 2007-2008 years by the author. Plates of the head and trunk shields, preliminarily determined as Eastmanosteus aff. E. pustulosus (Eastman), were found in the sandy clay deposits of the Ardatovka Horizon (Givetian, Middle Devonian) in the Pavlovsk Quarry, Voronezh Region. An incomplete anterior ventro-lateral plate of Dunkleosteidae gen. et sp. indet., similar to the same plates of the Dunkleosteus-species, was discovered in the sandy deposits of the Zadonsk Horizon (Lower Famennian, Upper Devonian) in the Lime Factory Quarry not far from Livny Town, Orel Region. The brief description of the new findings supplementing the data on the Middle-Late Devonian dunkleosteids of the Central Devonian field is given.

O DEVONIANO NO ESTADO DO MATO GROSSO DO SUL, BRASIL: NOVA ÁREA DE DISTRIBUIÇÃO E PRESENÇA DE TÍPICA FAUNA MALVINOCÁFRICA

Estratos devonianos são amplamente conhecidos na borda leste da Bacia do Paraná, particularmente no estado do Paraná. No entanto, os estudos são ainda escassos na borda noroeste, especialmente no estado do Mato Grosso do Sul. Durante estudos realizados para este trabalho foram levantados cerca de 120 sítios geológicos e paleontológicos na região, tendo sido identificadas algumas discrepâncias nos mapas de distribuição das unidades do Devoniano (Grupo Campos Gerais/Chapada) no referido estado. Neste trabalho é apresentada uma revisão da distribuição dos estratos do Devoniano no Mato Grosso do Sul, bem como um levantamento dos trabalhos paleontológicos na região que abordaram a típica fauna malvinocáfrica (Pragiano-Emsiano inicial), com intuito de incrementar a discussão sobre a gêneses dos depósitos do Devoniano no estado. A presença desta fauna, aliada a outras evidências estratigráficas, corrobora a não compartimentalização da Bacia do Paraná para esta idade. É levantada a hipótese de um tectonismo concomitante à deposição da Formação Ponta Grossa (=Grupo Chapada II inferior), principalmente para o topo da unidade, sugerida pelo contexto progradacional seguido de um hiato deposicional durante o Emsiano médio ao final do Eifeliano na área. É possível que o Arco de Campo Grande somente tenha adquirido expressividade geomorfológica no Emsiano médio, o que seria refletido na ausência de estratos datados como Emsiano tardio/Eifeliano em áreas aflorantes no estado e diversas outras evidências.

The first Early Devonian Dipnoi from the Holy Cross Mountains, Poland

Dipnoan remains are mainly known from the Middle and Upper Devonian deposits in the Holy Cross Mountains, Poland. The presence of this group in the Lower Devonian was suggested by feeding trace fossils apparently made by dipnoan fish. Recent studies confirm the occurrence of body fossils based on single skeleton elements. Fragments of heavily ossified mandible and skull-roof represent dipnoan remains appear to belong to a primitive ‘Dipnorhynchus’-like form. It supplements the knowledge on the Early Devonian ecosystem at the Holy Cross Mountains and dipnoan ichnological record is now supported by fossil remains of a putative trace-maker for Osculichnus isp.

Nature And Age of Granites in the Central Part of the Western Siberian Platform (Case Study of the Krivolutskii Batholith)

The study of granites in the basement of the Western Siberian platform is highly relevant since they are associated with hydrocarbon deposits, which are located not only above the granite massif, but also within the metasomatically altered upper layer of granites. At the same time, granites are most easily and reliably dated by zircon, which makes the geological structure of the area easier to examine, especially when the latter is overlapped by a thick sedimentary cover. The composition of granitoids from the basement of the Traigorod–Kondakovskii licensed site of the Western Siberian megabasin, located in the northwestern part of Tomsk Region, near the border with the Khanty-Mansi Autonomous Okrug, about 40 km east of the village of Aleksandrovskoye, has been studied. This license area is located within the Aleksandrovskii arch, which is bounded by the Ust-Tymsk Depression in the southeast and the Koltogorskii Trough in the northwest. The Aleksandrovskii Arch has a complex structure, which includes the large Krivolutskii granite batholith enclosed in the Carboniferous–Devonian sedimentary (mainly carbonate) rocks and Ordovician–Silurian shales. It has been established that batholith rocks are leucogranites and granites of normal alkalinity and have undergone metasomatic alterations in the form of propylitization and argillization. Granites belong to the I-type and were probably formed from the island arc substrate. Their age, according to the results of U–Pb zircon dating, is approximately 268 Ma; i.e., the generation and intrusion of granites took place during the beginning of the formation of the Koltogorsk–Urengoi Rift, the central rift of Western Siberia (which, according to Ar–Ar basalt dating, was also formed 268 million years ago).

Stratigraphic Characteristic Devon System Of Mountain Kuldzhuktau (South Tian-Shan)

This article presents the results of long-term stratigraphic studies on the territory of the Kuldzhuktau mountains. Schemes for the division and correlation of Devonian deposits have been created based on complete biostratigraphic data that most effectively reflect the geological age of local stratigraphic units and their reliable correlation with geological age. The tier units of the International Devonian Stratigraphic Scale are substantiated at the present stage of research. Due to the widespread use of conodonts, it was possible to clarify the physical and age volumes, as well as the sequence of Devonian deposits in the territory of Kuldzhuktau, and almost completely reconstruct the Devonian section.

Imbriea nom. nov., a replacement name for Orthopleura Imbrie, 1959 (Brachiopoda).

The genus Orthopleura Imbrie, 1959 (Brachiopoda: Rhynchonelliformea: Strophomenata: Orthotetida: Orthotetidina: Chilidiopsoidea: Areostrophiidae: Areostrophiinae, following the classification of Kaesler Selden 1997-2007) was erected to contain three species of extinct brachiopods from Devonian deposits in the United States. Orthopleura rhipis Imbrie, 1959 was assigned as the type species at time of erection. Streptorhynchus flabellum Whitfield, 1882, Schuchertella orthoplicata Stainbrook, 1943, and two undescribed species, "Orthopleura sp. A" and "Orthopleura sp. B", were treated as congeneric (Imbrie 1959). However, Orthopleura Imbrie, 1959 is a junior homonym of Orthopleura Spinola, 1845 (Insecta: Coleoptera: Cleridae), the latter being the type genus of the subfamily Orthopleurinae Böving Craighead, 1931: 56 (see also Opitz 2017 on the validity of this name), The aforementioned usage for the brachiopod taxon must be rejected because the name is not available per Article 60 of The International Code of Zoological Nomenclature (ICZN 1999, and henceforth "the Code"). The rejected junior homonym has no known available and potentially valid synonym and must be replaced by a new substitute name.

The Devonian–Carboniferous boundary in Belgium and surrounding areas

The Devonian–Carboniferous boundary is associated with a major extinction event of the Phanerozoic. It was also a time marked by a rapid but short-lasting change in deposition called Hangenberg Event. In the Namur–Dinant Basin the uppermost Devonian (‘Strunian’) deposits recorded a third-order transgression that produced a progressive switch from coastal siliciclastic to proximal mixed deposits with an increase of the carbonate production on the ramp. Hence, the Comblain-au-Pont and lower Hastiere formations are considered as the transgressive system tract, whereas the middle member of the Hastiere Formation is interpreted as the highstand system tract, capped by an erosion surface corresponding to the third-order sequence boundary. Superimposed on these third-order sequences are well-marked orbitally forced precession cycles (wet–dry climate alternations) of c. 18.6 ka, appearing as irregular c. 30–80-cm-thick couplets of limestone and calcareous shale beds. The Hangenberg Black Shale Event is locally present as dark shales that likely spread over the shelf, marking the maximum flooding surface of the sequence. Before and after this event, carbonate facies rich in benthic macrofauna and microfauna continued to develop. The Hangenberg Sandstone Event, appearing as a sandstone bed in pelagic sections, is variously recorded at the base of the Hastiere Formation, either as a sandy siltstone bed in proximal sections or as a horizon with limestone clasts and reworked fossils in more distal settings. The Hangenberg Sandstone Event beds occur sharply in the stratigraphic record and do not correspond to the long sea level fall of a third-order sequence boundary, but most probably to a short out-of-sequence event. The revision of the stratigraphic distribution of major fossil groups pleads for a continuous biostratigraphic succession with no obvious hiatus. The variable development of some micropalaeontological zones at the end of the Devonian is the result of complex eco-biostratigraphic interactions with the environment rather than the reflection of true hiatuses. It is marked by extinctions of Devonian taxa, concomitantly with the end of the reworking produced by the Hangenberg Sandstone Event, most probably immediately below the entry of the conodont Protognathodus kockeli. It is also coincident with the boundary between the foraminiferal zones DFZ7–MFZ1, rugose coral zones RC0–RC1 and between the palynozones LE–VI. After the short-lasting regressive phase of the Hangenberg Sandstone Event, normal depositional settings returned with the deposition of the Hastiere Formation. Hence, the end of the Hangenberg Sandstone Event is proposed as the most natural proxy to pinpoint the Devonian–Carboniferous boundary.

New Data on the Sterile and Fertile Structures, in situ Spores of Svalbardia osmanica Petrosjan et Radczenko (Archaeopteridales) from the Givetian of the Kuznetsk Basin, Russia

Svalbardia osmanica Petrosjan et Radczenko from the Middle Devonian deposits (Izyly Formation) of Kuznetsk Basin is re-studied from the type material (CNIGR-museum, Saint-Petersburg). An emended diagnosis of S. osmanica including new data on morphology and anatomy of sterile plant fragments and fertile structures with in-situ spores from the microsporangia is given. Dispersed spores from the same deposits that included S. osmanica indicates a Givetian age for the Izyly Formation.

The Beginning of the Development of Oil Fields in Ural-Volga Region in 1930s—1940s

The relevance of the study is determined by the significance of the accumulation of everything positive from the historical experience of implementing national projects, including the formation of the country’s oil and gas complex. On the basis of archival documents, issues related to the evolution of state policy in the field of searching for new oil fields in the Ural-Volga region on the eve and during the Great Patriotic War are considered. The novelty of the study is determined not only by the introduction of previously unpublished documents into scientific circulation, but also by an attempt to analyze the ongoing discussions about the prospects of this oil region, very contradictory decisions of the government in this regard. Attention is focused on such a miscalculation of the Soviet government in the pre-war period as a stake on the development of oil production, primarily in Azerbaijan and the North Caucasus. It has been proven that as a result, the oil workers of the Second Baku felt a lack of funds, equipment, and qualified personnel. It is concluded that as a result, only the first half of 1944 was marked by the largest event in the oil industry of our country: scientists confirmed the assumptions that there are multilayer oil fields in the area between the Volga and the Urals. The authors of the article argue that the discovery of new deposits was of strategic importance for the industrialization of the country, and later for the supply of oil products to the rear and front. It is emphasized that the development of the Devonian deposits of the Ural-Volga region, which began in 1944, became the basis for a sharp increase in oil production in this region.

Reconsidering the ‘phyllocarid’ from the Wade Creek Formation

The fossil record of phyllocarids in Australia is decidedly limited, with only a few specimens known from Ordovician to Devonian deposits. Therefore, the identification of examples from older deposits would uncover more facets of Gondwanan crustacean evolution. Here, a supposed phyllocarid reported by Chapman (1925) from the Mount John Shale Member of the Wade Creek Formation is reconsidered. We conclude that the ‘phyllocarid’-like structure is somewhat morphologically comparable to traces ascribed to the activity of bivalved arthropods. However, as the Mount John Shale Member is likely Mesoproterozoic in age, the most parsimonious explanation is that the structure is a cast created by abiotic activity. Re-examination of such specimens represents a useful approach to clarifying previous misidentifications in the literature and is an important application of historically valuable specimens and collections. R.D.C. Bicknell [rdcbicknell@gmail.com], Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, New South Wales, 2351, Australia; P.M. Smith [Patrick.Smith@austmus.gov.au], Palaeontology Department, Australian Museum Research Institute, Sydney, New South Wales, 2010, Australia; Department of Biological Sciences, Macquarie University, Sydney, New South Wales, 2109, Australia; N. Schroeder [Natalie.Schroeder@ga.gov.au] Geoscience Australia, Symonston ACT 2609, Australia; J. Kimmig [jkimmig@psu.edu] Earth and Mineral Sciences Museum & Art Gallery, Pennsylvania State University, University Park, PA 16802, USA.

Stratigraphic evolution of Silurian-Devonian deposits from Amazonas basin, north Brazil, and implication for the west Gondwana

The Silurian-Devonian transition in the southern margin of Amazonas Basin registers a transgressive-regressive succession deposited in a paleogeographic scenario adjacent to the western margin of Occidental Gondwana. The Silurian deposits from Pitinga Formation represent siltstone/sandy-claystone bed shapes distributed in bodies of tabular geometry in coarsening upward and bioturbated cycles deposited in a shoreface environment. The Devonian deposits forming Maecuru Formation represent gravel sandy beds organized in fining-upward cycles within tabular bodies deposited in a braided fluvial environment. The contact between the units is marked by an outstanding Eodevonian erosive surface related to Precordillera Orogeny. The Eodevonian discordance is also present in the stratigraphy of other Paleozoic Brazilian Basins. Pitinga Formation is associated with deglaciation events observed in the Silurian final stages. The amplitude of continental exposition generated conditions for the installation of fluvial systems in which the braided style predominates during a transition from Silurian to Devonian in the Amazonas Basin southern margin.

Late Devonian (Famennian) phacopid trilobites from western Mongolia

The early Famennian phacopid trilobites Feistops mongoliensis gen. nov. sp. nov., Feistops khovdensis gen. nov. sp. nov., ?Feistops sp. A, and ?Houseops olonbulagensis sp. nov. are recorded and illustrated from the western Mongolia Hushoot Shiveetiin gol section from the Baruunhuurai Terrane of the Central Asian Orogenic Belt (CAOB). In this section, exposing large parts of cyclic Famennian shallow-water siliciclastic shelf deposits, Feistops mongoliensis gen. nov. sp. nov., Feistops khovdensis gen. nov. sp. nov., ?Feistops sp. A, and ?Houseops olonbulagensis sp. nov. are the first known and described representatives of trilobites from Late Devonian deposits of western Mongolia. Their affinities with known other sighted species of the same age are discussed.

Shell Microstructure in Representatives of the Genus Lingulipora Girty from the Frasnian (Upper Devonian) Deposits of Southern Timan

The microstructure of the shell material in the protegulum brephic shells, and adult shells of Lingulipora gradata Batrukova, 1955 from the Upper Devonian deposits (Frasnian Stage) of South Timan is described. The structure of the interior part of the ventral valve was studied. The character of porosity was different in two species of the genus Lingulipora.

Tectonics of the Devonian Complex of the Southern Sector of the Caspian Basin (Kazakhstan): A Set of Geological and Geophysical Methods

The paper presents a comprehensive analysis of new data for drilling and seismic survey of the oil and gas potential of deep-seated Paleozoic horizons of the Caspian Basin in Kazakhstan. The features of the development and occurrence of large Paleozoic uplifts and sedimentary strata promising for prospecting are specified. A set of geological and geophysical methods was applied, and magnetic and gravitational anomalies of potential fields were analyzed in the southern, southeastern, and eastern marginal parts of the southeastern sector of the Caspian Basin. This is supplemented with new data obtained by a set of reconnaissance methods, and the section attributed to the Paleozoic at depths up to 5.5–8.0 km and its Devonian–Lower Carboniferous sequence are specified. New data were obtained on the area of distribution and occurrence of Upper Devonian and Lower Carboniferous sediments, geological conditions and prerequisites were revealed that refined the trace of the pre-Devonian complex and of the Lower–Middle Devonian sediments. Analysis of the distribution of large local prospecting objects has confirmed the presence and development of megauplifts, which are zones of hypsometrically elevated Devonian–Lower Carboniferous sediments. In the contour of the megauplift, structural elements have developed that are less significant, but promising in terms of hydrocarbon content. Based on the results of studying and refining the distribution patterns of large Devonian‒Lower Carboniferous objects and identifying megauplifts, it is possible to optimize regional studies in the Caspian Basin for the period of 2020–2030.

Secondary Dolomitization as a Factor Responsible for the Reservoir Properties of the Lower Devonian Sedimentary Rocks of the Eastern Wall of the Khoreiver Depression (Timan–Pechora Petroleum Basin)

The composition, structure, and secondary alteration of the Lower Devonian sedimentary rocks are characterized; the distribution of various types of pore spaces is analyzed and several types of dolomite structures are distinguished. The results of our works indicate that, depending on the permeability, solubility, and primary structure of the carbonate rocks or sediment, as well as the temperature, volume, and duration of influence of dolomitizing fluids, dolomitization can lead to an increase or decrease in porosity.

New investigations of Upper Devonian wood from the north of the European part of Russia

The paper describes a continuation of our research on the distribution of archaeopteridalean plants in the north of the European part of the Russian Federation. New data on archaeopterid wood remains from Upper Devonian deposits of Northern Timan are presented. Representatives of the genus Callixylon are documented: the type species C. trifilievii, fragments of stumps (or root systems) with C. zalesskyi wood, and a small branch of C. sp.

Secondary dolomitization as a factor determining the reservoir properties of the Lower Devonian deposits in Eastern edge of the Khoreyver depression (Timan-Pechora basin)

The Lower Devonian deposits were characterized in terms of their composition, texture and secondary transformations, the distribution of various types of pore space was analyzed and several types of dolomite textures were identified. The analysis showed that permeability, solubility and primary texture of carbonate rock or sediment, as well as temperature, volume and exposure time of dolomitizing fluids are key factors for dolomitization and depending on these factors dolomitization can lead to not only increase but also decrease of porosity.