Lower Carboniferous Formation Research Articles

Effect of Paleoenvironmental Conditions on the Distribution of Lower Carboniferous Shale in Yaziluo Rift Trough, South China: Insights from Major/Trace Elements and Shale Composition

Paleoenvironmental conditions significantly influence the distribution patterns and organic matter enrichment of shale. This study investigated the vertical variations of major elements, trace elements, and total organic carbon (TOC) in the Lower Carboniferous marine shale from the Yaziluo Rift Trough, South China, to understand the paleoenvironmental conditions, including redox conditions, terrigenous detrital input, paleoproductivity, and paleo-seawater depth. The Lower Carboniferous formation consists of three sedimentary facies: basin facies, lower slope facies, and upper slope facies. From the basin to the lower slope and then to the upper slope facies, TOC, quartz, and pyrite contents gradually decrease, whereas the carbonate mineral content shows an increasing trend. A continuous decline in paleo-seawater depth transformed a deep-water anoxic environment with high paleoproductivity and low detrital input in the basin facies into a semi-deep-water environment with dysoxic-oxic conditions and moderate detrital influx in the lower slope facies, evolving further into a suboxic environment with high detrital flux in the upper slope facies. The geochemistry results suggest that anoxic conditions and high paleoproductivity were the primary controls on organic matter enrichment in the siliceous shale of the basin facies. In contrast, redox conditions significantly influenced organic matter accumulation in the mixed shale of the lower slope facies, attributed to relatively low paleoproductivity in a more restricted marine setting. Additionally, the adsorption of carbon components by clay minerals facilitated the preservation of organic matter in the calcareous shale of the upper slope facies.

Conodonts of the Famennian stage Upper Devonian Tournaisian stage Lower Carboniferous Magnitogorsk ore field

The article is the first to publish materials on the conodont characteristics of the ore-bearing volcanogenic-sedimentary formations in the Magnitogorsk ore field. They were obtained during the of geological mapping in the late 80s. On the basis of the conodonts study, a detailed stratigraphic subdivision of the Upper Devonian and Lower Carboniferous formations lacking faunal characteristic, was made. In the composite section of the Shumilin Formation, an almost complete sequence of the Famennian Horizons of the Upper Devonian and the Tournaisian of the Lower Carboniferous stages were determined. In the Famennian the Makarovsky, Murzakaevsky, Kushelginsky and Lytvinsky Horizons of the West Urals stratigraphic scheme are distinguished. In the Tournaisian the Gumerovsky, Malevsky, Upinsky, Kosorechensky, Kizelovsky and Kos’vinsky Horizons are established.

Сharacteristic properties of the terrigenous reservoir development with underlying water by horizontal wells

The paper considers the issues of the development of Bobrikovsko-Radaevsky and Tula formations among the Arlansky and Yugomashevsky oilfields, which are classic examples of the development of terrigenous reservoir. The analysis of the operational parameters was carried out for horizontal wells that were drilled into the terrigenous part of the Lower Carboniferous formations. There is a problem of premature flooding of the wells, which has low specific production rate of recoverable reserves. The displacement characteristics are similar to the typical displacement characteristics for a reservoir with an active aquifer based on analogy analysis. According to the results of the calculations performed, it was revealed that the time to achieve critical water cut is affected by the volume of oil equal to the volume of the half-cylinder figure with a radius equal to the distance between the wellbore tracing and the position of the oil-water contact, as well as the fluid rate. Achieving ater cut for wells with active bottom waters is a natural process of formation development within the downhole zone volume. The influence of downhole pressure on displacement characteristics for wells from different groups was studied. Wells were grouped according to the liquid rate, and it was shown that the displacement characteristics are improving for a group of wells with increasing liquid rate. Keywords: terrigenous reservoir; oil; oilfield; horizontal well; water cut; fluid flow rate; forced extraction; bottom water; displacement characteristics.

Characteristics of matrix-related pores associated with various lithofacies of marine shales inside of Guizhong Basin, South China

Matrix-related pore characteristics of between Lower Carboniferous shale and Middle Devonian shale in Guizhong Basin were investigated to explore the reservoir capacity. Via the combination of organic geochemistry analysis, X-ray diffraction, gas adsorption, mercury intrusion porosimetry, helium porosimetry and focused ion beam-scanning electron microscopy, material basics and physical properties were studied. Five lithofacies were divided as comparable units in two formations according to thermal maturity, OM abundance and mineral components, namely organic-moderate argillaceous shale with high thermal maturity (OMAS-H) and organic-lean argillaceous shale with high thermal maturity (OLAS-H) in Lower Carboniferous Formation, and organic-lean mixed shale with over thermal maturity (OLMS-O), organic-rich mixed shale with over thermal maturity (ORMS-O) as well as organic-rich calcareous shale with over thermal maturity (ORCS-O) in Middle Devonian Formation. Results showed that (1) OMAS-H and OLAS-H performed better porous features than OLMS-O, ORMS-O and ORCS-O, in terms of PV, PSA and porosity, (2) pores developed better in OMAS-H and OLAS-H than those in OLMS-O, ORMS-O and ORCS-O, in terms of pores of rigid grains, pores associated with clay flakes and OM-hosted pores, (3) specific PVs of OM were dramatically larger than those of mineral components, while specific PVs of OM in both OMAS-H (0.348 ml/g × 10−6) and OLAS-H (0.248 ml/g × 10−6) were about an order of magnitude higher than those in OLMS-O (0.055 ml/g × 10−6), ORMS-O (0.025 ml/g × 10−6) and ORCS-O (0.011 ml/g × 10−6). The ability of pore contribution largely depends on whether corresponding components are suited in the appropriate evolution stage with suitable thermal and pressure circumstance. Then sufficient degree of pore carriers (matrixes) need to be thought about, especially OM and clay as the secondary pore providers. Also, the demand for pore preservation highlights the importance of brittle minerals which can establish rigid frameworks. Therefore, in the case of controlling factors on pore characteristics, the importance ranking should be taken into consideration.

New evidence of effusive and explosive volcanism in the Lower Carboniferous formations of the Moroccan Central Hercynian Massif: Geochemical data and geodynamic significance

The Azrou-Khénifra basin, located in the SE sector of the Moroccan Central Hercynian Massif of the Western Meseta of Morocco comprises volcanic and volcanoclastic rocks where two magmatic sequences can be distinguished: i) the Dhar Lahmar Sequence, composed of Upper Visean basaltic lava flows and pyroclastic deposits; and ii) the Kef Al Asri Sequence, composed of Visean – Serpukhovian intermediate to acid rocks.A continuous spatial and temporal evolution between the two volcano-sedimentary sequences was observed during the detailed geological work performed in the studied area. Petrography and geochemical studies additionally suggest a continuous compositional evolution from the more basic magmatic rocks to the intermediate/acid rocks, which implies a cogenetic magmatic differentiation controlled by crystal fractionation (with minor crustal assimilation) of a calc-alkaline trend magmatic suite. The inferred magmatic evolution is consistent with a geodynamic environment of an orogenic zone within an active continental margin setting.This partly explosive Visean – Serpukhovian volcanism, identified for the first time in the Western Meseta of Morocco, displays very similar petrographic and geochemical characteristics to its Eastern Meseta analogues, which implies that the emplacement of these magmatic rocks must have occurred in similar collisional geodynamic settings for both major geological domains, further constraining the evolution of this major crustal segment within the Carboniferous events that shaped the Hercynian Orogeny.

Литолого - геофизические свойства сланцевых пород с повышенным содержание керогена

The key features of unconventional shale hydrocarbon accumulations include the following: a) all source rocks act as low permeability oil and gas res-ervoir rocks requiring no cover rock; b) effective pore space is distributed within the bulk of mature kerogen resulting from katagenetic transformations in organic material. Evaluating the properties of reservoir rocks with a high content of kerogen attracts a lot of interest due to new approaches to unconven-tional hydrocarbon exploration and the challenge of applying the technology of hydraulic fracturing in low-permeability formations. This research into the lithological and physical properties of facies with a high kerogen content was prompted by a correlation between the sedimentary features of the proven productive shale formations and similar formations of different ages in the Dnieper-Donets basin. The sedimen-tary conditions of shale formation in DDb being similar to those of forming oil and gas producing shales with a high content of kerogen in Utica/Point Pleasant paleobasins, the highest kerogen content was assumed to be associated with certain lithotypes holding interest for further study. Mathematical equations were derived to describe the correlation between radioactivity, uranium content, bulk density, electrical resistivity and organic carbon content for shales from the Utica formation and the DDb shales. There were clarified mathematical dependences of bulk density on organic carbon content for a number of Lower Carboniferous formations in DDb. As using separate mathematical expressions is likely to pro-duce results of doubtful validity, preference should be given to a system of equations to describe the nature of changes in different physical prop-erties of shales depending on the organic component content. That will provide accurate data on the share of kerogen in the studied reservoir rocks. Values of hydrogen and oxygen indices only predict low molecular weight products and their subsequent extraction. The findings on the lithological properties and mathematical relationships have been reported and discussed at international conferences.

Preface

The lithostratigraphic guide of Belgium is subdivided into ten chapters dealing respectively with Cambriam-Ordovician-Silurian formations, Devonian formations, Lower Carboniferous formations, Upper Carboniferous formations, Permian formations, Triassic and Jurassic formations, Cretaceous formations, Paleogene and Neogene formations, Quaternary formations. The different chapters have been prepared by the respective national stratigraphic subcommissions set up by the Belgian National Committee for Geological Sciences.

Das Eindringen von Neophyten in anthropogen geschaffene Standorte und ihre Vergesellschaftung am Beispiel von Senecio inaequidens DC. )

The dispersal of neophytes depends on the effect of man’s influence on his environment. The recent producing of disturbed vegetation area and of new dispersal ways is responsible for the conquering of new species in strange regions. Not more than 20 years were necessary for the South-African species Senecio inaequidens DC. to appear very frequently in the region of Aachen (the most western town of FRG). The main locations of this weed are waste-heaps of coal, new and constantly disturbed sites of the city and along railways and highways especially in the area of Upper-Devonian and Lower-Carboniferous formations as well as in loess regions. The colonisation of S. inaequidens starts in a very early stage of the succession. On most habitats the early pioneer stadium appears to be the most important site condition. Within 49 releves of S. inaequidens on different locations around Bremen and Aachen the high number of accompanying species (176) shows a wide ecology amplitude of site conditions.

The Lower Carboniferous formations in the Hikoroichi region, southern Kitakami Mountains, northeast Japan (PartII):Sedimentological study of sandstone and limestone

The Lower Carboniferous formations in the Hikoroichi region, southern Kitakami Mountains, northeast Japan (PartII):Sedimentological study of sandstone and limestone

The Lower Carboniferous formations in the Hikoroichi region, southern Kitakami Mountains, northeast Japan (Part I):Stratigraphy of the Hikoroichi Formation

The Lower Carboniferous formations in the Hikoroichi region, southern Kitakami Mountains, northeast Japan (Part I):Stratigraphy of the Hikoroichi Formation

Wave‐generated structures and sequences from a shallow marine succession, Lower Carboniferous, County Cork, Ireland

ABSTRACTIn a Lower Carboniferous formation south of Cork, Ireland, characterized by sand/mud alternations at varying scales, several lithotypes could be singled out on the basis of relative sand content and primary sedimentary structures. The lithotypes are arranged in several types of sequences: coarsening upwards, coarsening‐fining upwards, random, and in rare instances: fining upwards.With increased gross sandcontent the sand intercalations thicken and show a richer array of structures, reflecting a wider range of energy conditions. The majority of the structures is interpreted as wave generated. Current formed structures play an insignificant role. Tidal effects could not be ascertained. The alternation of low‐ and high‐energy lithotypes, occurring in sandy as well as muddy parts of the sequences is explained as resulting from the interplay of storm and fair weather conditions. The effect of shoaling bathymetry is reflected in sequences by an increasing importance of high‐energy lithotypes.The environment of deposition can be visualized as a muddy shallow marine platform on which longshore directed sandy shoals were formed under the influence of wave action. Depending on the degree of wave agitation and the availability of sand the shoals reached different stages of maturity: incipient, submerged or emergent. The sequential type encountered in vertical sections depends on the location of the line of logging and varies laterally as sandlenses thicken, amalgamate or die out.

The age and composition of the Whin Sill and the related dikes of the north of England

The system of intrusive sheets in the Lower Carboniferous formations of the north of England, familiar to geologists throughout the world as the Great Whin Sill, has a voluminous early literature which it is unnecessary to summarize here. It will be sufficient to refer to the classical papers by Topley and Lebour on the field relationships (1) and by Teall on the detailed petrography (4), each of which contains an ample bibliography of the earlier literature. The most recent general account is by Prof. E. J. Garwood (9), who contributed a careful discussion of the evidence bearing on the period of intrusion.Teall's great paper closely followed on one devoted to some of the dikes of the north of England (3), and in it he drew attention to the remarkable petrographical Similarity between the rocks of the Heft and High Green dikes and that of the Whin Sill (4, p. 656).

The Geology of the Northern Border of Dartmoor between Whiddon Down and Butterdon Down

In this paper the Lower Carboniferous formation bordering the granite of Dartmoor for a length of about 4½ miles, between Whiddon Down on the west and Butterdon Down towards the east, are the only stratified rocks dealt with; but the nature of, and variations found in the granite south of the Carboniferous rocks are also considered. The area examined includes part of the deep gorge of the River Teign, known as Fingle Glen, between Hunter's Tor and about a mile east of Fingle Bridge, or rather more than two-thirds of the length of the gorge. The area described is covered by the 6-inch Ordnance Survey quarter-sheets of Devon:—LXXVII, S.E.; LXXVIII, S.W.; LXXVIII, S.E.; XC, N.W.; and XC, N.E. Of these quarter-sheets only the whole of LXXVIII, S.W. is covered; but portions of the other sheets are required to describe the area in a comprehensive manner. In the area dealt with, the Lower Carboniferous, or Culm Measures, may, as found by Mr. R. H. Worth (10) in the granite-border south-west of Okehampton, be divided into two groups: the Lower Aluminous Series and the overlying Calcareous Series. Both these series of rocks have been affected by contact-meta-morphism from the granite. The Lower Aluminous Series in this district can be divided into zones: the lower zone characterized by the occurrence of much segregated or disseminated iron-pyrites, and the upper zone in which chiastolite is found. The Lower Aluminous Series passes upwards by gradual change, and without any physical feature, from black slates into

Some Recent Advances in General Geology

AMONG the recent researches on organic remains none are of greater geological interest and importance than those relating to the Radiolaria. The tiny siliceous structures which belong to this Order of Protozoa have long been recognised in our formations, but the part they have played in building up portions of the stony structure of the earth has not until lately been realised. The most striking evidence was that brought forward by Prof. Edgeworth David and Mr. E. F. Pittman (Quart. Journ. Geol. Soc., vol. lv. p. 16, 1899). They describe, a great series of siliceous limestones, jaspers and claystones, with interstratified coral limestones and plant-beds, and submarine tuffs, the whole attaining a thickness of over 9000 feet, and; extending over many hundred square miles in New South Wales. In the bulk of these rocks Radiolaria are present at the rate of about one million to the cubic inch, and among the forms Dr. G. J. Hinde has recognised twenty-nine genera and fifty-three species. Taken as a whole, the deposits are fine-grained, and bear evidence of having been laid down in clear sea-water, beyond reach of any but the finest sediment. They do not indicate any very considerable depth ot water; but they tell of a vast lapse of time, and of conditions which prevented the dispersal over the area of coarse detritus. What exactly were these conditions it remains for future research to discover. In this country, in Devonshire and Cornwall, the occurrence of radiolarian cherts, both of Ordovician and Carboniferous ages, has been made known through the observations of Dr. Hinde, Mr. Howard Fox and Mr. Teall. The more prominent of these rocks are found in the Lower Carboniferous formation of Coddon Hill near Barnstaple, where the chert-beds have long been known, although their organic origin, was not until recently discovered. The freedom of the beds from mechanically-formed detritus has led to the supposition that these strata were deposited-in deep water and at some distance from the coast, although the associated strata above and below the chert-beds do not lend support to the hypothesis. The fact is that at the present time the only extensive radiolarian deposits known to be in process of accumulation are in the deeper oceanic regions.

The geology of the oil shalefields of the Lothians

1. Introductory . In quitting the Presidential chair of the Edinburgh Geological Society at the end of my term of office, which it has been a pleasure no less than an honour for me to have occupied during the last two years of the bright Nineteenth Century, it has occurred to me that this opportunity might be taken to speak of a subject that has engaged much of my time and attention during the last fifteen years, the first three of which were spent as an officer on the staff of H.M. Geological Survey. The geology of the oil shalefields in the neighbourhood of Edinburgh is a branch of local geology well within the scope of this Society's work, and although the oil industry has existed in this part of Scotland for more than thirty years, no reliable general account has ever been published of the important section of the Lower Carboniferous formation which has so greatly conduced to the well-being of a large district and its people. Such a subject has many features of interest both to the scientific and the economic mind, and I now propose to speak in a popular way of some of the results of my geologisings, in the hope of being able to throw a little new light on the relationships and character of the rocks that have themselves been made, during this generation, to throw so much light over dark places in many a European country. It is not my intention

IV.—Heer's Flora Fossilis Arctica

In vol. ii. of his Flora Fossilis Arctica, Professor Oswald Heer has treated of the Fossil Flora of Bear Island, and shown that it belongs to the Lower Carboniferous Formation, of which it forms the lowest beds (named by him the “Ursa” beds), close to the junction with the Devonian. The Yellow Sandstone of Kiltorcan in Ireland, the Grauwacke of the Vosges, and the southern part of the Black Forest, and of St. John in Canada, belong to the same group. In the summer of 1870 two young Swedish naturalists (Wilander and Nathorst) discovered this same formation in the Klaas Billen Bay of the Eisfiord in Spitzbergen, and brought home fine specimens of Lepidodendron Veltheimianum, and Stigmaria ficoides. It has also been found in West Greenland, for Prof. Nordenskiold tells us that the Swedish expedition, which went to Disco in the course of last summer, to fetch the meteorite, weighing 25 tons, which he discovered at Ovifak in that island, has brought home fossil plants of true Carboniferous age.

On the Lower Carboniferous Brachiopoda of Nova Scotia

A t the request of Dr. J. W. Dawson, F.R.S., F.G.S., Principal of M'Gill University, Montreal, I have examined the Brachiopoda collected by him from the Lower Carboniferous formation of Nova Scotia, as well as those obtained by Sir C. Lyell during his first journey in America, and I now submit the result of this examination to the Geological Society. The geology of Nova Scotia has already received the attention of several distinguished observers; and I may mention that, although prior to Sir C. Lyell's visit to the country in question Mr. R. Brown had described the limestone of East River and Cumberland as Lower Carboniferous, the limestones of Windsor and Shubenacadie were at that time regarded as “New Red Sandstone” or “Permian.” Sir C. Lyell was the first to maintain that the whole was of Carboniferous age; and, by so doing, he unravelled a complication which might for a time have involved the geology of the country in much confusion. He may therefore justly claim to have been the first geologist who was able to determine the geological age of the Gypsiferous strata of Nova Scotia, which he considered to be a member of the Carboniferous group instead of the Triassic or the Permian, or both of them, as previously conjectured*. Dr. Dawson informs me that his first papers on the subject were the results of investigations which he made to test Sir C. Lyell's views, and that Mr. Brown and he followed up these observations, and accumulated a vast

On the Flora of the Silurian, Devonian, and Lower Carboniferous Formations

W hile thanking you for your valuable work ‘Siluria,’ which you have had the kindness to send me, I have the honour of announcing to you that I have completed my work on the ‘Flora of the Silurian, Devonian, and Lower Carboniferous Formations’ It is already printed, and will be published at the expense of the Imperial Academy of Naturalists at Jena, accompanied by twelve lithographic and photographic plates*. The number of all the fossil plants in the said formations amounts to 185 species. They are distributed ( a ) according to the orders or natural families, thus Five of these belong to the Algæ; one to terrestrial plants— Siyillaria Hausmanni , Goepp., found by M. Hausmann in 1807 (Reise in Scandinavien, vol. v.; Kjerulf, Geolog. der südlichen Norwegens, p. 87) near Idre and Särne. It is perhaps the most interesting plant of the whole work. One terrestrial plant, Sagenaria Weltheimiana , from the schist of Hamilton County, New York; but you and M. Verneuil consider that these beds belong to the Upper Devonian formation, in which, in Silesia, Thuringia, Ireland, and in the so-called Chemung? and Catskill formations of the State of New York, a much larger number of terrestrial plants has been found, amongst which this species of Sagenaria also occurs. This formation contains fifty-seven species, of which seven belong to the Algœ; the others are terrestrial, and belong to the families which are found up to the close of the Palæozoic period, viz. the Ferns, Calamineœ, Equisetaceœ, Lepidodendreœ, Lycopodiaceœ, Sigillarieœ, Coniferœ , and Nœggerathieœ

On a Gap in the Greywacke Formation of the Eastern Lammermuirs filled by Old Red Sandstone Conglomerate

T he occurrence of vast masses of conglomerate on both sides of the Lammermuir chain has been well known to geologists since the days of Hutton and Hall. It appears, however, never to have been suspected that the formations of the north and south sides were connected by a band of considerable breadth running completely across the chain from Doon Hill, about two miles from Dunbar, to the Hardens Hills, about the same distance west from Dunse. The position, extent, and relations to the adjoining strata of this interesting formation of conglomerate will be best understood by reference to the accompanying sketch (see Map). The whole district occupied by the greywacke, conglomerate, and trap rocks is almost uniformly hilly, the height of the hills ranging from about 800 to 1400 feet above sea-level, those composed of conglomerate being in general fully as high as those consisting of greywacke or igneous rocks. The tracts occupied by the strata of the old red sandstone and lower carboniferous formations are much lower and flatter, and generally rise no higher than 300 or 400 feet above the level of the sea. The conglomerate occupies a trough in the greywacke, evidently the result of an ancient dislocation of great extent. At the margins it is seen overlapping the upturned ends of the greywoacke strata, which are generally either vertical, or dip at angles of 45° or upwards, to about W.N.W., the dip being rather steeper on the east side of the conglomerate than on the west.