scholarly journals Exceptionally preserved calcified sponge assemblagesin Upper Jurassic carbonates of the eastern Getic Carbonate Platform (Southern Carpathians, Romania)

2021 ◽  
Author(s):  
George PLEŞ ◽  
Felix SCHLAGINTWEIT ◽  
Iuliana LAZĂR ◽  
Ioan I. BUCUR ◽  
Emanoil SĂSĂRAN ◽  
...  
Keyword(s):  
Carbonate Platform ◽  
Distribution Patterns ◽  
Upper Jurassic ◽  
Nutrient Competition ◽  
Carbonate Platforms ◽  
Diagnostic Features ◽  
Carbonate Production ◽  
Reef Area ◽  
Morphological Adaptations ◽  
Calcified Sponges

A rich poriferan assemblage was identified within the easternmost part of the Getic Carbonate Platform of Romania (Grădiștei Gorges). The excellent preservation state of most poriferans here led to the discovery of a new species (Neuropora gigantea Pleș & Schlagintweit, n. sp.) and to the identification of previously unknown diagnostic features in some species (Sarsteinia babai Schlagintweit & Gawlick, 2006 emend., Neuropora lusitanica Termier, 1985, Sphaeractinia steinmanni Canavari, 1893). Calciagglutispongia yabei Reitner, 1992, Sarsteinia babai and Sphaeractinia steinmanni are reported for the first time from the Upper Jurassic carbonates of the Getic Carbonate Platform. The sedimentary input fluctuations and the nutrient competition had an important role in understanding the morphological adaptations of the analysed species. The existing palaeoecological and palaeoenvironmental conditions generated different distribution patterns towards the reef profile and also preferential adaptations to a specific Tethyan domain. As opposed to the poriferan assemblages from the northern Tethyan shelves, these organisms formed sponge-coral-microencruster boundstones at the margins and fore-reefal zones of isolated carbonate platforms within the intra-Tethyan realm. The importance of calcified sponges in reef-zonation is highlighted by the establishment of a general zonation model. Three zones can be distinguished: 1) Cladocoropsis-Milleporidium zone (back-reef area); 2) Bauneia-Chaetetopsis-Parastromatopora zone (central reef area); and 3) Sphaeractinia/Ellipsactinia-Neuropora zone for the fore-reef area. In the absence of a true reef framework these calcified sponges developed typical morphologies, environmental adaptations and partnerships with other biotic groups which strongly influenced the carbonate production throughout the intra-Tethyan domain.

scholarly journals The siliciclastics/carbonates shift in the Jurassic of the Western Caucasus (central northern Neo-Tethys): reconsidering research over the last 50 years

Geologos ◽  
2019 ◽  
Vol 25 (2) ◽  
pp. 153-162 ◽  
Author(s):  
Dmitry A. Ruban
Keyword(s):  
Sea Water ◽  
Current Knowledge ◽  
Carbonate Platform ◽  
Temporal Distribution ◽  
Tectonic Activity ◽  
Carbonate Platforms ◽  
Western Caucasus ◽  
Carbonate Production ◽  
The Western Caucasus ◽  
Spatio Temporal

Abstract A chain of carbonate platforms evolved in the northern Neo-Tethys during the Late Jurassic, but current knowledge remains incomplete as long as data from several larger regions, such as the Western Caucasus, are not included. In order to fill this gap, it is here suggested to reconsider the information accumulated chiefly during Soviet times. Although these data are too general, they still matter with regard to some regional characteristics and tentative interpretations. Available data on the spatio-temporal distribution of Bajocian-Callovian sedimentary rocks are summarised in a novel way which permits documentation of depositional trends at six representative localities in the Western Caucasus. The extent of the carbonate platform increased at two localities since the Late Callovian and at a third since the Middle Oxfordian. Three additional sites were characterised either by non-deposition or deep-marine sedimentation. The onset of carbonate platform development marked a remarkable shift from chiefly siliciclastic to carbonate deposition, although this event was not sudden everywhere. The Bathonian pulse of tectonic activity, coupled with the eustatic sea level rise, allowed shelves to expand during the Callovian-Oxfordian, with a reduction in siliciclastic input from islands and sea-water that became well oxygenated and warmer. These conditions were conducive to biogenic carbonate production, allowing the carbonate platform to expand subsequently.

An Integrated Approach To Forward Modeling Carbonate Platform Development

1994 ◽  
Author(s):  
Helmut Mayer
Keyword(s):  
Carbonate Platform ◽  
Sediment Accumulation ◽  
Integrated Approach ◽  
Forward Modeling ◽  
Carbonate Platforms ◽  
Carbonate Production ◽  
Geometric Evolution ◽  
Sediment Redistribution ◽  
Key Variables ◽  
The One

The forward model presented here is designed to simulate stratigraphic and geometric development of carbonate platforms. Starting from an initial basement geometry, the effects of a number of key variables on water depth are combined for each time increment. This procedure is repeated in an iterative fashion for subsequent time steps. The variables considered include subsidence, carbonate production, sediment redistribution, compaction, isostatic compensation, and eustatic sea-level change. Time- or depth-dependent functions are developed for these variables. Free parameters in these functions allow fitting to realistic magnitudes. A sample simulation demonstrates the characteristics of the model and indicates its usefulness in case studies and predictions. In recent years a number of studies on the modeling of sediment accumulation in various basin settings has been published. Most of them are concerned with clastic basin fill or do not discriminate lithologies (e.g., Turcotte and Kenyon, 1984; Kenyon and Turcotte, 1985; Tetzlaff, 1986; Bitzer and Harbaugh, 1987; Flemings and Jordan, 1987, 1989; Tetzlaff and Harbaugh, 1989; Jervey, 1989), while only few focus on mixed clastic/carbonate systems (e.g., Aigner et al., 1989; Lawrence et al., 1990) or carbonate platforms (e.g., Lerche et al., 1987; Bice, 1988; Demicco and Spencer, 1989; Scaturo et al., 1989). Sediment accumulation and distribution on a carbonate platform and the adjacent slope represent a highly complex system of numerous interdependent factors which in concert determine the development of the stratigraphy and geometry of the platform. The goal of this study is to develop a model that yields a "best compromise" between two principal targets: representation of all important variables in geologically reasonable functional relationships on the one hand, and simplicity on the other. Forward modeling of sedimentary systems serves to simulate the stratigraphic and geometric evolution of the system, dependent on variations in the input parameters. The purpose of this approach is to establish the critical variables and parameters which dominate the system and to produce a geologically reasonable generic stratigraphic pattern. The next step then would be to use the model to reproduce known patterns of actual modern or ancient sedimentary systems (inverse modeling).

scholarly journals Carbonate platform production during the Cretaceous

2020 ◽  
Vol 132 (11-12) ◽  
pp. 2606-2610 ◽  
Author(s):  
Alexandre Pohl ◽  
Yannick Donnadieu ◽  
Yves Godderis ◽  
Cyprien Lanteaume ◽  
Alex Hairabian ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Carbonate Platform ◽  
Carbonate Platforms ◽  
Carbon Cycle Model ◽  
Carbonate Production ◽  
Volcanic Degassing ◽  
First Order ◽  
Carbonate Deposition ◽  
Underlying Mechanisms ◽  
Unimodal Pattern

Abstract Platform carbonates are among the most voluminous of Cretaceous deposits. The production of carbonate platforms fluctuated through time. Yet, the reasons for these fluctuations are not well understood, and the underlying mechanisms remain largely unconstrained. Here we document the long-term trend in Cretaceous carbonate platform preservation based on a new data compilation and use a climate-carbon cycle model to explore the drivers of carbonate platform production during the Cretaceous. We show that neritic carbonate preservation rates followed a unimodal pattern during the Cretaceous and reached maximum values during the mid-Cretaceous (Albian, 110 Ma). Coupled climate-carbon cycle modeling reveals that this maximum in carbonate deposition results from a unique combination of high volcanic degassing rates and widespread shallow-marine environments that served as a substrate for neritic carbonate deposition. Our experiments demonstrate that the unimodal pattern in neritic carbonate accumulation agrees well with most of the volcanic degassing scenarios for the Cretaceous. Our results suggest that the first-order temporal evolution of neritic carbonate production during the Cretaceous reflects changes in continental configuration and volcanic degassing. Geodynamics, by modulating accommodation space, and turnovers in the dominant biota probably played a role as well, but it is not necessary to account for the latter processes to explain the first-order trend in Cretaceous neritic carbonate accumulation in our simulations.

About this title - Seismic Characterization of Carbonate Platforms and Reservoirs

10.1144/sp509 ◽  
2021 ◽  
Vol 509 (1) ◽  
pp. NP-NP
Author(s):  
J. Hendry ◽  
P. Burgess ◽  
D. Hunt ◽  
X. Janson ◽  
V. Zampetti
Keyword(s):  
Seismic Data ◽  
Oil And Gas ◽  
Carbonate Platform ◽  
Carbonate Platforms ◽  
Oil And Gas Exploration ◽  
Seismic Modelling ◽  
Flow Units ◽  
Development Data ◽  
Seismic Characterization

Modern seismic data have become an essential toolkit for studying carbonate platforms and reservoirs in impressive detail. Whilst driven primarily by oil and gas exploration and development, data sharing and collaboration are delivering fundamental geological knowledge on carbonate systems, revealing platform geomorphologies and how their evolution on millennial time scales, as well as kilometric length scales, was forced by long-term eustatic, oceanographic or tectonic factors. Quantitative interrogation of modern seismic attributes in carbonate reservoirs permits flow units and barriers arising from depositional and diagenetic processes to be imaged and extrapolated between wells.This volume reviews the variety of carbonate platform and reservoir characteristics that can be interpreted from modern seismic data, illustrating the benefits of creative interaction between geophysical and carbonate geological experts at all stages of a seismic campaign. Papers cover carbonate exploration, including the uniquely challenging South Atlantic pre-salt reservoirs, seismic modelling of carbonates, and seismic indicators of fluid flow and diagenesis.

scholarly journals Triassic metasediments in the internal Dinarides (Kopaonik area, southern Serbia): stratigraphy, paleogeographic and tectonic significance

2010 ◽  
Vol 61 (2) ◽  
pp. 89-109 ◽  
Author(s):  
Senecio Schefer ◽  
Daniel Egli ◽  
Sigrid Missoni ◽  
Daniel Bernoulli ◽  
Bernhard Fügenschuh ◽  
...  
Keyword(s):  
Shallow Water ◽  
Lower Triassic ◽  
Turbidity Currents ◽  
Distal Margin ◽  
Carbonate Platforms ◽  
Carbonate Production ◽  
Tectonic Significance ◽  
Internal Dinarides ◽  
Water Carbonate ◽  
Shallow Water Carbonate

Triassic metasediments in the internal Dinarides (Kopaonik area, southern Serbia): stratigraphy, paleogeographic and tectonic significanceStrongly deformed and metamorphosed sediments in the Studenica Valley and Kopaonik area in southern Serbia expose the easternmost occurrences of Triassic sediments in the Dinarides. In these areas, Upper Paleozoic terrigenous sediments are overlain by Lower Triassic siliciclastics and limestones and by Anisian shallow-water carbonates. A pronounced facies change to hemipelagic and distal turbiditic, cherty metalimestones (Kopaonik Formation) testifies a Late Anisian drowning of the former shallow-water carbonate shelf. Sedimentation of the Kopaonik Formation was contemporaneous with shallow-water carbonate production on nearby carbonate platforms that were the source areas of diluted turbidity currents reaching the depositional area of this formation. The Kopaonik Formation was dated by conodont faunas as Late Anisian to Norian and possibly extends into the Early Jurassic. It is therefore considered an equivalent of the grey Hallstatt facies of the Eastern Alps, the Western Carpathians, and the Albanides-Hellenides. The coeval carbonate platforms were generally situated in more proximal areas of the Adriatic margin, whereas the distal margin was dominated by hemipelagic/pelagic and distal turbiditic sedimentation, facing the evolving Neotethys Ocean to the east. A similar arrangement of Triassic facies belts can be recognized all along the evolving Meliata-Maliac-Vardar branch of Neotethys, which is in line with a ‘one-ocean-hypothesis’ for the Dinarides: all the ophiolites presently located southwest of the Drina-Ivanjica and Kopaonik thrust sheets are derived from an area to the east, and the Drina-Ivanjica and Kopaonik units emerge in tectonic windows from below this ophiolite nappe. On the base of the Triassic facies distribution we see neither argument for an independent Dinaridic Ocean nor evidence for isolated terranes or blocks.

scholarly journals The biostratigraphic record of Cretaceous to Paleogene tectono-eustatic relative sea-level change in Jamaica

2018 ◽  
Author(s):  
David Patrick Gold ◽  
James P. G. Fenton ◽  
Manuel Casas-Gallego ◽  
Vibor Novak ◽  
Irene Pérez-Rodríguez ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Carbonate Platform ◽  
Caribbean Region ◽  
Level Curve ◽  
Relative Sea Level ◽  
Carbonate Production ◽  
Platform Drowning ◽  
Relative Sea Level Rise ◽  
Strong Control

The island of Jamaica forms the northern extent of the Nicaraguan Rise, an elongate linear tectonic feature stretching as far as Honduras and Nicaragua to the south. Uplift and subaerial exposure of Jamaica during the Neogene has made the island rare within the Caribbean region, as it is the only area where rocks of the Nicaraguan Rise are exposed on land. Biostratigraphic dating and palaeoenvironmental interpretations using larger benthic foraminifera, supplemented by planktonic foraminifera, nannopalaeontology and palynology of outcrop, well and corehole samples has enabled the creation of a regional relative sea-level curve through identification of several depositional sequences. This study recognises ten unconformity-bounded transgressive-regressive sequences which record a complete cycle of relative sea level rise and fall. Sequences are recognised in the Early to ‘Middle’ Cretaceous (EKTR1), Coniacian-Santonian (STR1), Campanian (CTR1), Maastrichtian (MTR1-2), Paleocene-Early Eocene (PETR1), Eocene (YTR1-3) and Late Eocene-Oligocene (WTR1). These transgressive-regressive cycles represent second to fourth order sequences, although most tie with globally recognised third order sequences. Comparisons of the Jamaican relative sea-level curve with other published global mean sea-level curves show that local tectonics exerts a strong control on the deposition of sedimentary sequences in Jamaica. Large unconformities (duration >1 Ma) are related to significant regional tectonic events, with minor overprint of a global eustatic signal, while smaller unconformities (duration <1 Ma) are produced by global eustatic trends. The relatively low rates of relative sea-level rise calculated from the regional relative sea-level curve indicate that carbonate production rates were able to keep pace with the rate of relative sea-level rise accounting for the thick successions of Maastrichtian carbonates and those of the Yellow and White Limestone Groups. Carbonate platform drowning within the White Limestone Group during the Oligocene to Miocene is attributed to environmental deterioration given the low rates of relative sea-level rise.

scholarly journals Seismic characterisation of carbonate platforms and reservoirs: an introduction and review

2021 ◽  
pp. SP509-2021-51
Author(s):  
J. Hendry ◽  
P. Burgess ◽  
D. Hunt ◽  
X. Janson ◽  
V. Zampetti
Keyword(s):  
Seismic Data ◽  
Large Scale ◽  
Carbonate Platform ◽  
Energy Transition ◽  
Carbonate Platforms ◽  
Seismic Attribute ◽  
Sequence Stratigraphic ◽  
3D Data ◽  
Diagenetic Facies ◽  
Central Atlantic

AbstractImproved seismic data quality in the last 10–15 years, innovative use of seismic attribute combinations, extraction of geomorphological data, and new quantitative techniques, have significantly enhanced understanding of ancient carbonate platforms and processes. 3D data have become a fundamental toolkit for mapping carbonate depositional and diagenetic facies and associated flow units and barriers, giving a unique perspective how their relationships changed through time in response to tectonic, oceanographic and climatic forcing. Sophisticated predictions of lithology and porosity are being made from seismic data in reservoirs with good borehole log and core calibration for detailed integration with structural, paleoenvironmental and sequence stratigraphic interpretations. Geologists can now characterise entire carbonate platform systems and their large-scale evolution in time and space, including systems with few outcrop analogues such as the Lower Cretaceous Central Atlantic “Pre-Salt” carbonates. The papers introduced in this review illustrate opportunities, workflows, and potential pitfalls of modern carbonate seismic interpretation. They demonstrate advances in knowledge of carbonate systems achieved when geologists and geophysicists collaborate and innovate to maximise the value of seismic data from acquisition, through processing to interpretation. Future trends and developments, including machine learning and the significance of the energy transition, are briefly discussed.

Impact of basin architecture on diagenesis and dolomitization in a fault-bounded carbonate platform: outcrop analogue of a pre-salt carbonate reservoir, Red Sea rift, NW Saudi Arabia

2019 ◽  
Vol 26 (3) ◽  
pp. 448-461 ◽  
Author(s):  
Khalid Al-Ramadan ◽  
Ardiansyah Koeshidayatullah ◽  
Dave Cantrell ◽  
Peter K. Swart
Keyword(s):  
Red Sea ◽  
Elevated Temperatures ◽  
Carbonate Platform ◽  
Isotope Analysis ◽  
Carbonate Reservoir ◽  
Carbonate Platforms ◽  
Hydrocarbon Reservoir ◽  
Red Sea Rift ◽  
Platform Margin ◽  
Clumped Isotope

The early Miocene Wadi Waqb carbonate in the Midyan Peninsula, NE Red Sea is of great interest not only because of its importance as an archive of one of the few pre-salt synrift carbonate platforms in the world, but also as a major hydrocarbon reservoir. Despite this importance, little is known about the diagenesis and heterogeneity of this succession. This study uses petrographical, elemental chemistry, stable isotope (δ13C and δ18O) and clumped isotope (Δ47) analyses to decipher the controlling processes behind the formation of various diagenetic products, especially dolomite, from two locations (Wadi Waqb and Ad-Dubaybah) that have experienced different diagenetic histories. Petrographically, the dolomites in both locations are similar, and characterized by euhedral to subhedral crystals (50–200 µm) and fabric-preserving dolomite textures. Clumped isotope analysis suggests that slightly elevated temperatures were recorded in the Ad-Dubaybah location (up to 49°C), whereas the Wadi Waqb location shows a sea-surface temperature of c. 30°C. These temperature differences, coupled with distinct δ18OVPDB values, can be used to infer the chemistry of the fluids involved in the dolomitization processes, with fluids at the Wadi Waqb location displaying much higher δ18OSMOW values (up to +4‰) compared to those at the Ad Dubaybah location (up to −3‰). Two different dolomitization models are proposed for the two sites: a seepage reflux, evaporative seawater mechanism at the Wadi Waqb location; and a fault-controlled, modified seawater mechanism at the Ad-Dubaybah location. At Ad-Dubaybah, seawater was modified through interaction with the immature basal sandstone aquifer, the Al-Wajh Formation. The spatial distribution of the dolostone bodies formed at these two locations also supports the models proposed here: with the Wadi Waqb location exhibiting massive dolostone bodies, while the dolostone bodies in the Ad-Dubaybah location are mostly clustered along the slope and platform margin. Porosity is highest in the slope sediments due to the interplay between higher precursor porosity, the grain size of the original limestone and dolomitization. Ultimately, this study provides insights into the prediction of carbonate diagenesis in an active tectonic basin and the resultant porosity distribution of a pre-salt carbonate reservoir system.

A review of the carbonaria-subgroup of Fannia Robineau-Desvoidy (Diptera: Fanniidae), with descriptions of two new species from China

Zootaxa ◽  
2009 ◽  
Vol 2204 (1) ◽  
pp. 37-47 ◽  
Author(s):  
MING-FU WANG ◽  
DONG ZHANG ◽  
SHUANG ZHENG ◽  
CHUN-TIAN ZHANG
Keyword(s):  
New Species ◽  
Distribution Patterns ◽  
Systematic Position ◽  
Diagnostic Features ◽  
The World ◽  
Two New Species ◽  
Geographic Distributions ◽  
World Fauna

The Fannia carbonaria-subgroup belongs to the Fannia carbonaria-group Chillcott, 1961. The world fauna of this subgroup is reviewed, the diagnostic features of the subgroup are redefined, and a key to the males of the known species is given. Two new species from China are described: F. dorsovittata Wang sp. nov. and F. subfuscitibia Wang sp. nov.. To facilitate comparisons of the species, Fannia corvina (Verrall), Fannia imperatoria Nishida and Fannia xiaoi Fan are redescribed. Geographic distributions of the species of the subgroup are updated. The systematic position and distribution patterns of the F. carbonaria-subgroup are discussed.

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