scholarly journals Petro-mineralogical and geochemical characteristics of Shahaba Limestone from Gogi-Kanchankayi sector, Bhima Basin, Karnataka with reference to Uranium mineralisation

2021 ◽  
Vol 38 (1) ◽  
pp. 23-32
Author(s):  
Debasish Roy ◽  
Dheeraj Pande ◽  
Sikta Patnaik ◽  
S K Varughese ◽  
A K Pradhan ◽  
...  
Keyword(s):  
Carbonate Platform ◽  
Low Energy ◽  
Energy Conditions ◽  
Carbonaceous Matter ◽  
Shallow Marine ◽  
P2o5 Content ◽  
Marine Carbonate ◽  
Uranium Mineralisation ◽  
Siliceous Limestone ◽  
Basin Margin

The Shahabad Limestone Formation of Bhima Basin from Gogi-Kanchankayi area occurs in heterogeneous forms like massive/blocky limestone, argillaceous/ siliceous limestone and laminated/ flaggy limestone. These limestones are primarily composed of micrite, which often alters into sparry calcite on diagenesis with associated impurities of quartz, feldspar, barite, chlorite, glauconite, sulphides and carbonaceous matter. Geochemically, these limestones comprises of variable CaO with low MgO and P2O5 content. Trace elements concentration shows elevated Ba, Rb and depleted Sr. The current study classified these limestones as non-dolomitic and non-phosphatic types deposited in shallow marine carbonate platform setting with low energy conditions. Post-sedimentation, basin tectonics has resulted in reactivation of the basin margin fault causing intense fracturing of limestone. Subsequent hydrothermal movement along those fractures has resulted in re-mobilisation and re-precipitation of sulphides and carbonaceous matter, and along with alteration has facilitated the precipitation of the uranium bearing minerals.

scholarly journals STUDYING IN THE PAXOS ZONE THE CARBONATE DEPOSITIONAL ENVIRONMENT CHANGES DURING UPPER CRETACEOUS, IN SAMI AREA OF KEFALLINIA ISLAND, GREECE

2017 ◽  
Vol 43 (2) ◽  
pp. 793
Author(s):  
E. Zoumpoulis ◽  
F. Pomoni-Papaioannou ◽  
A. Zelilidis
Keyword(s):  
Depositional Environment ◽  
Upper Cretaceous ◽  
Carbonate Platform ◽  
Upward Trend ◽  
Shallow Marine ◽  
Sedimentary Environments ◽  
Stratigraphic Analysis ◽  
Marine Carbonate ◽  
Carbonate Sequence ◽  
Shallow Subtidal

The shallow-marine carbonate sequence of Sami (Kefallinia isl. Fig. 1) is a part of the Upper Cretaceous carbonate platform of the Paxi zone. Detailed lithostratigraphic and microfacies analysis of that sequence revealed clear periodicities and cyclicity. The high-resolution stratigraphic analysis has shown a number of lithofacies organized in groups (lithofacies associations), suggesting, on the whole, sedimentary environments ranging from lagoonal to peritidal context. The vertical arrangement of these lithofacies allowed the identification of a cyclic recurrence of the depositional and early diagenetic features, including a meteoric overprint on top of the elementary cycles. The cycles exhibit a shallowing upward trend from shallow subtidal to inter-supratidal and hypersaline facies, in a warm shallow marine environment.

scholarly journals SEDIMENTOLOGY AND BIOSTRATIGRAPHY OF AN UPPER TRIASSIC CARBONATE SUCCESSION OF TRIPOLITZA PLATFORM IN MARI AREA, PARNON MOUNTAIN, SE PELOPONNESUS, GREECE

2018 ◽  
Vol 40 (1) ◽  
pp. 101
Author(s):  
M. Kati ◽  
A. Zambetakis-Lekkas ◽  
E. Skourtsos
Keyword(s):  
Carbonate Platform ◽  
Upper Triassic ◽  
Shallow Marine ◽  
Carbonate Sedimentation ◽  
Subaerial Exposure ◽  
Arid Conditions ◽  
Southern Margin ◽  
Time Period ◽  
Marine Carbonate ◽  
Semi Arid

The Upper Triassic succession in the base of Tripolitza carbonate platform, in the Mari area of the Parnon Mt. in SE Peloponnesus, mostly consists of dolomites and to a lesser extent ofcalcitic dolomites. A detailed fades analysis and biostratigraphical study revealed that during Norian — Rhaetian times inter-supratidal and subtidal (shallow lagoonal) fades presenting cyclic development were deposited in the inner platform, similar to those that were formed in most of the Alpine platforms of the southern margin of the Tethys during the same time period. Diagenetic considerations further indicate that this shallow marine carbonate sedimentation was interrupted by subaerial exposure intervals and subsequent early lithification of the recently deposited sediments. The extensive and, mainly, early dolomitization and recrystallization, the presence of meteoric-vadose cements and specifically the repeated appearance of dolocrete horizons in the upper parts of many peritidal cycles, clearly show periodic subaerial exposure of the sediments, as well as the prevalence of semi-arid conditions in the area.

The Early Devonian atrypoid brachiopod Tibetatrypa n. gen. from Xizang (Tibet, China)

1986 ◽  
Vol 60 (2) ◽  
pp. 286-292
Author(s):  
Paul Copper ◽  
Hou Hong-Fei
Keyword(s):  
South China ◽  
Western Europe ◽  
Carbonate Platform ◽  
The South ◽  
The Urals ◽  
Early Devonian ◽  
Shallow Marine ◽  
Marine Carbonate ◽  
Sayan Region

Early Devonian (Pragian-Emsian) rocks in the Xainza region of central Xizang (Tibet) yield a shallow-marine, carbonate-platform fauna of corals, brachiopods, dacryoconarids, nautiloids and conodonts, among which Tibetatrypa n. gen. is locally a prominent constituent. The fauna broadly resembles that of western Europe, the Altai-Sayan region, the Urals and western Qinlin province of China, but differs from the South China faunas. Tibetatrypa, related to the Silurian genus Nalivkinia, is the youngest and largest member of the subfamily Clintonellinae, and is the first Devonian brachiopod described from Tibet.

scholarly journals Aspects of the Cenozoic stratigraphy of the Northern Sulaiman Ranges, Pakistan

1997 ◽  
Vol 16 (1) ◽  
pp. 51-58 ◽  
Author(s):  
R. W. Jones
Keyword(s):  
Carbonate Platform ◽  
Shallow Marine ◽  
Sequence Stratigraphic ◽  
Depositional Settings ◽  
Marine Carbonate ◽  
Stratigraphic Framework ◽  
Lithostratigraphic Units

Abstract. The results of micropalaeontological, nannopalaeontological and palynological analyses of Cenozoic sections from the Northern Sulaiman Ranges in Pakistan are discussed. They are in keeping with previously published results (though in some cases significantly more refined). They enable placement of most of the sampled lithostratigraphic units in a global bio- and sequence-stratigraphic framework. Limestones appear to be associated with essentially transgressive global sequences, shales with essentially regressive sequences. Palaeoenvironmental interpretations indicate a range of depositional settings from continental through shallow marine to basinal. A number of shallow marine carbonate platform sub-environments are recognized over the Palaeocene–Eocene section

scholarly journals A New Bioevent Stratigraphy of Late Jurassic Arab-D Carbonates of Saudi Arabia

GeoArabia ◽  
1996 ◽  
Vol 1 (3) ◽  
pp. 417-434
Author(s):  
Geraint Wyn Hughes
Keyword(s):  
Saudi Arabia ◽  
High Frequency ◽  
Late Jurassic ◽  
Carbonate Platform ◽  
Abu Dhabi ◽  
Fine Scale ◽  
Shallow Marine ◽  
Carbonate Sedimentation ◽  
Marine Carbonate ◽  
Productivity Rate

ABSTRACT A series of fine-scale biofacies cycles are recognised by the application of semiquantitative micropalaeontological analysis of cores in eight wells from the reservoir carbonates from the Arab-D and upper Jubaila formations in Saudi Arabia. They are of Kimmeridgian - Tithonian age, and form the primary producing reservoir of the world’s largest single continuous reservoir located in the Ghawar field of Saudi Arabia. Three new composite biozones are identified that include a basal, deep marine Biozone D3 with fining-upwards cycles which equate, in part, with the Jubaila Formation. Biozone D2 was deposited in shallower conditions of the lower Arab-D carbonate, and Biozone D1 deposited in a very shallow marine environment of the upper Arab-D carbonate; both zones contain multiple coarsening-upwards cycles. Numerous additional bio-events, of potential subzonal value, are detected within these broad zones, and are considered to be related to discrete shoaling-upwards responses to transgressive episodes. The proposed scheme differs significantly from that erected for the Arab-D Formation in offshore Abu Dhabi. Carbonates of the Arab-D member are concluded to be composed of a series of high frequency palaeobathymetric changes which were superimposed upon an extensive carbonate platform. Gradual shallowing of the platform resulted possibly from a reduction in subsidence rate, a fall in sea level, rise in carbonate productivity rate or a combination of these. The latest episode of very shallow marine carbonate sedimentation terminated with the deposition of the Arab-D evaporites.

First report of Acanthochaetetes (Porifera: Demospongiae) from the Cretaceous Khalsi Formation, Ladakh Himalaya, India

2021 ◽  
pp. 1-9
Author(s):  
Prasenjit Barman ◽  
Francisco Sánchez-Beristain ◽  
Shruti Ranjan Mishra ◽  
Mohd Ibrahim ◽  
Narendra Kumar Swami ◽  
...  
Keyword(s):  
Growth Form ◽  
Carbonate Platform ◽  
Sedimentation Rates ◽  
Shallow Marine ◽  
Faunal Assemblages ◽  
Marine Carbonate ◽  
Upper Hauterivian ◽  
Ladakh Himalaya ◽  
New Finding ◽  
First Time

Abstract The Cretaceous chaetetid sponge Acanthochaetetes huauclillensis Sánchez-Beristain and García-Barrera is reported for the first time from the Aptian–Cenomanian Khalsi Formation, Ladakh Himalaya, India. Its low- to high-domical growth form could suggest an adaptation to either an environment with constant sedimentation rates, or to an irregular substrate. However, these growth forms also may indicate an absence of important environmental/sedimentological changes during the lifespan of the sponges. In addition, the growth form of this species suggests a calm, non-turbulent, reef-like microenvironment. Along with the other faunal assemblages, such as the rudists, corals, and the gastropod Nerinea, A. huauclillensis indicates a tropical to subtropical shallow marine carbonate platform setting. This new finding extends its stratigraphic range from the upper Hauterivian to the Aptian–Cenomanian interval in the eastern Tethyan realm.

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