Palaeoenvironments and palynofacies of a pulsed transgression: the late Devonian and early Dinantian (Lower Carboniferous) rocks of southeast Wales

1991 ◽  
Vol 128 (4) ◽  
pp. 355-380 ◽  
Author(s):  
J. R. Davies ◽  
A. McNestry ◽  
R. A. Waters
Keyword(s):  
Coastal Plain ◽  
Depositional Environments ◽  
Late Devonian ◽  
Lower Carboniferous ◽  
Palynological Analysis ◽  
Red Sandstone ◽  
South Wales ◽  
Kerogen Type ◽  
Event Stratigraphy ◽  
Size Sorting

AbstractTwo boreholes in the Vale of Glamorgan have provided new data on the nature of the early Dinantian (Courceyan) transgression in South Wales. This transgression is manifested by the transition from the largely fluviatile, late Devonian, Upper Old Red Sandstone (Quartz Conglomerate Group) to the predominantly marine, early Dinantian, Lower Limestone Shale Group. The marine sequence comprises five shoaling upwards cycles, constructed from a suite of sedimentary lithofacies which record deposition in environments ranging from coastal plain, peritidal, lagoon, barrier and embayment to subtidal, open marine shelf. Each cycle represents a pulse of the transgression, and each successive pulse appears to have been larger than the preceding one, introducing progressively less restricted and more distal marine environments.Thirty-seven samples were processed for palynological analysis. Miospore biozonation supports the cycle correlations between the two boreholes, suggested by the sedimentary event stratigraphy. Detrital kerogens from the samples comprise both terrestrially derived and marine types in varying proportions. Each kerogen type is described as well as the size, sorting and preservation of each assemblage. A palynofacies profile is presented for eachof the depositional environments recognized.

Basin history deduced from subtle changes in fluvial style: a study of distal alluvium from the Devonian of southwest Ireland

1992 ◽  
Vol 83 (4) ◽  
pp. 655-667 ◽  
Author(s):  
John R. Graham ◽  
Andrea James ◽  
Kenneth J. Russell
Keyword(s):  
Coastal Plain ◽  
Depositional Environments ◽  
Upper Devonian ◽  
Small Scale ◽  
Basin Evolution ◽  
Progressive Reduction ◽  
Red Sandstone ◽  
Extensional Basin ◽  
Subsidence Rate ◽  
Ephemeral Channels

AbstractTwo detailed sections through 4 km of distal alluvium of the Upper Devonian Old Red Sandstone in the Munster Basin, southern Ireland, display a limited number of lithofacies. There is little ordering of these lithofacies on a small scale but changes in the proportions of lithofacies through time define a sequence of stages of basin evolution. The depositional environments changed progressively from sheetflood dominant, via mobile ephemeral channels and floodplains to a more fixed channel–overbank system and eventually to a coastal plain. On the basis of the sedimentary record a progressive reduction in subsidence rate with time is deduced as the main control on the evolution of the basin fill. This deduction is consistent with predictions from previously applied extensional basin models, but is insufficiently refined at present to distinguish between the different models.

scholarly journals X. The fossil flora of the culm measures of North-west Devon, and the palœobotanical evidence with regard to the age of the beds

1905 ◽  
Vol 197 (225-238) ◽  
pp. 291-325 ◽  
Keyword(s):  
Carbonaceous Material ◽  
Physical Structure ◽  
Fossil Flora ◽  
The South ◽  
Lower Carboniferous ◽  
Red Sandstone ◽  
North West ◽  
The North ◽  
South Wales ◽  
Plant Remains

The deposits of Upper Palæozoic age in the south-west of England differ remarkably in their general characters from those developed on the north side of the Bristol Channel. This conclusion applies not only to the Devonian rocks, but also to the succeeding Carboniferous series. In South Wales and Monmouth, the Devonian beds are of the Old Red Sandstone type, whereas, the Devonian succession of North Devon exhibits a marked, though not an entire change, in both petrological characters and palæontological facies; a change which becomes even more marked in the series of limestones, volcanic, and detrital deposits developed in the southern portion of that county. The South Wales coalfield, the largest and most important productive measures in this country, consists of a sequence of coal-bearing strata, resting upon beds of Lower Carboniferous age, for the most part similar in character to those occurring in our other English coalfields. In Devonshire, and in portions of the neighbouring counties of Somerset and Cornwall, a Carboniferous basin of considerable size is developed, occupying more than 1,200 square miles. In many important respects these rocks again differ somewhat markedly from their equivalents in South Wales. They form a succession of deposits of a somewhat abnormal type; being composed of sediments of extremely varied nature and origin, both detrital and organic. They are especially characterised by a general absence of carbonaceous material of any economic importance. These Carboniferous rocks are spoken of as the Culm Measures, a name first applied to them by Sedgwick and Murchison in 1837. These authors in their classic memoir, published in 1840, gave the first accurate description of the physical structure of the beds, and proved conclusively their Carboniferous age. It may be pointed out, however, that De la Beche, in 1834, was the first to indicate the Upper Carboniferous age of that portion of the Culm Measures which forms the subject of this memoir; his conclusion being based on plant remains identified by Professor Lindley. De la Beche also added considerably to our knowledge of the Culm Measures in his ‘Report on the Geology of Cornwall and Devon,’ published in 1839. Since then, John Phillips, Holl, T. M. Hall, and others, and, in more recent times, Messrs. Hinde and Fox, and Mr. Ussher, have all contributed important information on this subject.

scholarly journals The origin and early radiation of terrestrial vertebrates

2001 ◽  
Vol 75 (6) ◽  
pp. 1202-1213 ◽  
Author(s):  
Robert L. Carroll
Keyword(s):  
Fossil Record ◽  
Early Carboniferous ◽  
Late Devonian ◽  
Lower Carboniferous ◽  
Major Transitions ◽  
Terrestrial Vertebrates ◽  
History Of ◽  
Paleozoic Tetrapods ◽  
Early Radiation ◽  
Ways Of Life

The origin of tetrapods from sarcopterygian fish in the Late Devonian is one of the best known major transitions in the history of vertebrates. Unfortunately, extensive gaps in the fossil record of the Lower Carboniferous and Triassic make it very difficult to establish the nature of relationships among Paleozoic tetrapods, or their specific affinities with modern amphibians. The major lineages of Paleozoic labyrinthodonts and lepospondyls are not adequately known until after a 20–30 m.y. gap in the Early Carboniferous fossil record, by which time they were highly divergent in anatomy, ways of life, and patterns of development. An even wider temporal and morphological gap separates modern amphibians from any plausible Permo-Carboniferous ancestors. The oldest known caecilian shows numerous synapomorphies with the lepospondyl microsaur Rhynchonkos. Adult anatomy and patterns of development in frogs and salamanders support their origin from different families of dissorophoid labyrinthodonts. The ancestry of amniotes apparently lies among very early anthracosaurs.

Sedimentology and Evolution of the Fluvial-Deltaic System: A Modern Depositional Model Analog from the Red Sea Coastal Region, Saudi Arabia

2021 ◽  
Author(s):  
Osman Abdullatif ◽  
Mutasim Osman ◽  
Mazin Bashri ◽  
Ammar Abdlmutalib ◽  
Mohamed Yassin
Keyword(s):  
Red Sea ◽  
Coastal Plain ◽  
Depositional Environments ◽  
Hydrocarbon Reservoirs ◽  
Sediment Supply ◽  
Arabian Shield ◽  
Space And Time ◽  
Groundwater Aquifers ◽  
Coastal Sabkha ◽  
Lithofacies Association

Abstract Siliciclastic sediments represent important lithological unit of the Red Sea coastal plain. Their subsurface equivalents are important targets of groundwater aquifer and hydrocarbon reservoirs in the region. The lithofacies of the modern fluvial deltaic system has several distinct geomorphic units and sub-environments such as alluvial, fluvial, delta plain, aeolian, intertidal, coastal sabkha and eustuarine sediments. This study intends to characterize the lithofacies and the depositional environments and to produce an integrated facies model for this modern fluvial-deltaic system. The study might provide a valuable modern analog to several important subsurface Neogene formations that act as important hydrocarbon reservoirs and groundwater aquifers. The study integrates information and data obtained from landsats, maps and detailed field observation and measurements of facies analysis of the fluvial and deltaic along traveses from the Arabian Shield to the Red Sea coast. The lithofacies sediment analysis revealed four main lithofacies associations namely lithofacies A,B,C ad D. Lithoacies Associations A, which represents the oldest unit is dominated by coarse gravel with minor sands facies. While the lithofacies B is dominated byfine gravel and sand lithofacies, occasionally pebbly, vary from horizontal, planar to massive sands with minor laminated to massive silts and mud facies. The lithofacies in A and B show lateral proximal to distal variation as well as characteristic vertical stacking patterns. The Facies Association A and B indicates a change in fluvial depositional styles from gravelly alluvial fans to gravelly sandy fluvial systems. The lithofacies association C represents the recent fluvial system which consists of minor gravel lag deposits associated maily with various sand lithofacies of planner, horizontal and massive sand associated with massive and limainted sand and mud lithofacies. The lithofacies Association D is dominated with Barchan sand dunes local interfigger with muddy iinterdunes and sand sheets. Lithofacies D occupies rather more distal geomporphic position of the fluvial deltaic system that is adjace to coastal sabkha. The lithofacies associations described here document the evolution and development of the coastal plain sediments through space and time under various autocyclic and allocyclic controls. This included the tectonics and structural development associated with the Red Sea rifting and opening since the Oligocene – Miocene time. Others controls include the evolution of the Arabian shield (provenance) and the coastal plain through space and time as controlled by tectonics, sediment supply, climate and locally by autocyclic environmental This study might be beneficial for understanding the controls and stratigraphic evolution of the Red Sea region and will be of great value for reservoir and aquifer characterization, development and management. This modern analog model can also help in providing geological baseline information that would be beneficial for understanding similar ancient fluvial deltaic sediments. The study might provide guides and leads to understand the subsurface facies, stratigraphic architecture and heterogeneity of any potential groundwater aquifers and hydrocarbon reservoirs.

IMPACT RESILIENCE: ECOLOGICAL RECOVERY OF A CARBONATE FACTORY IN THE WAKE OF THE LATE DEVONIAN IMPACT EVENT

Palaios ◽  
2020 ◽  
Vol 35 (1) ◽  
pp. 12-21
Author(s):  
BENJAMIN E. RENDALL ◽  
LEIF TAPANILA
Keyword(s):  
Marine Invertebrate ◽  
Depositional Environments ◽  
Ecological Resilience ◽  
Late Devonian ◽  
Impact Event ◽  
Geographic Ranges ◽  
Marine Communities ◽  
Before And After ◽  
The Alamo ◽  
The Impact

ABSTRACT Conformable limestone deposits bracketing the Alamo breccia (Late Devonian, Nevada) provide a robust dataset for comparisons of depositional environments and marine communities before and after a significant meteor impact. Rank abundances of more than 3000 faunal identifications from 158 sampling localities cluster in three major faunal groups that are arranged in an onshore-offshore lithofacies gradient. Comparison of faunal clusters before and after the impact show little to no dissimilarity. The recovery of marine invertebrate communities following the Alamo impact event was geologically instantaneous. Broad geographic ranges of the fauna may have contributed to ecological resilience. From a geologic perspective, marine communities appear to rebound quickly and fully following meteor impacts, leaving impact-related extinctions as outliers that correspond only to the largest impacts.

scholarly journals Geochemical characteristics and depositional environments of the Narimba Formation source rock, Bass Basin, Australia

2020 ◽  
Vol 10 (8) ◽  
pp. 3207-3225
Author(s):  
Mohamed Ragab Shalaby ◽  
Muhammad Izzat Izzuddin bin Haji Irwan ◽  
Liyana Nadiah Osli ◽  
Md Aminul Islam
Keyword(s):  
Source Rock ◽  
Vitrinite Reflectance ◽  
Depositional Environments ◽  
Geochemical Characteristics ◽  
Type Ii ◽  
Wet Gas ◽  
Kerogen Type ◽  
Rock Characterization ◽  
Rock Eval ◽  
Oil Gas

Abstract This research aims to conduct source rock characterization on the Narimba Formation in the Bass Basin, Australia, which is made of mostly sandstone, shale and coal. The geochemical characteristics and depositional environments have been investigated through a variety of data such as rock–eval pyrolysis, TOC, organic petrography and biomarkers. Total organic carbon (TOC) values indicated good to excellent organic richness with values ranging from 1.1 to 79.2%. Kerogen typing of the examined samples from the Narimba Formation indicates that the formation contains organic matter capable of generating kerogen Type-III, Type-II-III and Type-II which is gas prone, oil–gas prone and oil prone, respectively. Pyrolysis maturity parameters (Tmax, PI), in combination with vitrinite reflectance and some biomarkers, all confirm that all samples are at early mature to mature and are in the oil and wet gas windows. The biomarkers data (the isoprenoids (Pr/Ph), CPI, isoprenoids/n-alkanes distribution (Pr/nC17 and Ph/nC18), in addition to the regular sterane biomarkers (C27, C28 and C29) are mainly used to evaluate the paleodepositional environment, maturity and biodegradation. It has been interpreted that the Narimba Formation was found to be deposited in non-marine (oxygen-rich) depositional environment with a dominance of terrestrial plant sources. All the analyzed samples show clear indication to be considered at the early mature to mature oil window with some indication of biodegradation.

Lower Devonian plant and spore assemblages from Lower Old Red Sandstone strata of Tredomen Quarry, South Wales

2011 ◽  
Vol 165 (3-4) ◽  
pp. 183-208 ◽  
Author(s):  
Jennifer L. Morris ◽  
John B. Richardson ◽  
Dianne Edwards
Keyword(s):  
Lower Devonian ◽  
Red Sandstone ◽  
South Wales
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