Facies Architecture and Sedimentary Structures in the drill cores of Uranium Bearing Sediments of Banganapalle Formation of Palnad Sub-basin, Guntur District, Andhra Pradesh

The Banganapalle Formation, the lowest member of the Neoproterozoic Kurnool Group of rocks, resting over the basement granites, has been identified as the host rock for uranium in Koppunuru area in the western part of Palnad sub-basin. The uppermost arenite facies of the Banganapalle Formation is exposed on surface and shows only few bedform indicators like ripple marks, planer laminations etc. Down-hole lithological examinations on course of core drilling in Koppunuru and adjoining areas identified five recognizable lithofacies of Banganapalle Formation, viz. basal conglomerate unit, quartzite-shale intercalated facies, and two quartz arenite facies separated by a grey shale dominated argillaceous facies. The polymictic conglomerate, with unsorted grit to pebble size clasts of granite, shale, quartzite, vein quartz and dolerite indicate short distance transportation and derivation from nearby granitoids traversed by quartz reef/dolerite dykes. Cyclic repetitions of arenaceous and argillaceous sediments in Banganapalle lithocolumn above the basal conglomerates point to alternate rhythmic marine transgression and regression regimes. These units can also be discriminated based on their sedimentary texture, bedforms and several soft-sedimentary penecontemporaneous deformational structures (PCD) like load structure, convolute bedding/laminations, and slump structures such as micro-slips, gravity faults and folds. These syn-sedimentary structures clearly indicate perturbation and submergence of the basin contemporaneous to deposition. Cross-beds suggests change in current direction/intensity while bi-directional symmetrical ripples in outcrops of upper arenite facies suggests that the Banganapalle sediments are derived from the basement granitoids exposed to the north as well as upper Cuddapah sediments to its west. Overall, the sedimentary structures, textural and composition variation of the lithounits suggest deposition of these sediments in marginal marine, inter- to supra-tidal flat environment. The porous and permeable nature of the quartz arenite and the basal conglomerates and the presence of available reductants in the form of sulphides and carbonaceous matter make them the best suited loci for fluid movement and precipitation of uranium.

New data on the stratigraphy of Badenian from Krčedin area (Northern Serbia, Central Paratethys)

Badenian sediments are found for the first time in the surroundings of the Krcedin village. They represent remnants of the Central Paratethys marginal sea. The sediments are represented by a basal conglomerate unit overlain by pure and sandy marl. Foraminifera and rare ostracods are present, limited to the marls. Normal gradation and the prevalence of planktonic foraminifera suggest a rapidly deepening basin.

Evidence of young, proximal and primary (YPP) diamond source occurring in alluviums in the Santo Antônio do Bonito, Santo Inácio and Douradinho rivers in Coromandel region, Minas Gerais

ABSTRACT: Magmatism associated with the Alto Paranaíba structural high comprises kimberlites, kamafugites, and alkaline complexes, forming an approximately 400 x 150 km NW-SE belt in the southern São Francisco Craton. Dating of some intrusions reveals ages between 120 and 75 Ma. Chemical analyses of garnet recovered in alluvium from traditional diamond digging areas indicate peridotitic garnet windows in Três Ranchos and Coromandel. Six hundred and eighty (680) diamonds acquired or recovered during mineral exploration in the digging areas of Romaria, Estrela do Sul, Três Ranchos and Coromandel show unique characteristics, certain populations indicating young, proximal and primary sources (YPP). Analyses of 201 stones from Santo Antônio do Bonito, Santo Inácio and Douradinho rivers alluvium, Coromandel, present no evidence of transport, characterizing a proximal source. Within these river basins, exposures of the Late Cretaceous Capacete Formation basal conglomerate contain mainly small rounded and/or angular quartzite pebbles and of basic and ultrabasic rocks, as well as kimberlite minerals (garnet, ilmenite, spinel, sometimes diamond). A magnetotelluric profile between the Paraná and Sanfranciscana basins shows that the thick underlying lithosphere in the Coromandel region coincides with the peridotitic garnet window and with a diamond population displaying proximal source characteristics. Diamond-bearing kimberlite intrusions occur in different areas of Alto Paranaíba.

A new eusuchian (Crocodylia) tooth from the Early or Middle Paleocene, with a description of the Early–Middle Paleocene boundary succession at Gemmas Allé, Copenhagen, Denmark

A recently found crocodylian tooth crown from the basal conglomerate of the Middle Paleocene (Selandian) Lellinge Greensand Formation, differs morphologically from other finds of crocodylian teeth from the Paleocene of southern Scandinavia. The tooth is conical and blunt with a narrow rounded apex, and slightly curved along the axis of its length. The morphology of the tooth suggests it belongs to either the longirostrine eusuchian Aigialosuchus, which is known from the Campanian of southern Sweden, or to a member of the Alligatoridae which are the most common crocodylians in northern Europe in the Late Cretaceous. Gavialoid crocodylians, in particular Thoracosaurus which is known from the Danian limestome of the Limhamn quarry in southern Sweden and from the Faxe quarry in eastern Denmark, can be excluded because of their deviating tooth morphology. Regardless of its assignment, the tooth is interesting in a stratigraphic context as it demonstrates the existence of at least two crocodylian taxa in Scandinavia during the Early and Middle Paleocene.

Analysis of Sedimentary Facies Model - The Cretaceous Bottom Conglomerate of Xinjiang Junggar Basinludong Area as an Example

This paper aims to Cretaceous bottom conglomerate facies of Xinjiang Ludong area of China research to elucidate the deposition pattern analysis phase, as well as the use of methods. Methods first take logging combined with tectonic pattern and sedimentary background, division comparing in Ludong area of Cretaceous basal conglomerate unit. Secondly, the application of modern sedimentology theory, method, system analysis of lithologic characteristics of this area and sedimentary structure feature. According to the logging facies analysis, summarized the various sedimentary facies marks, distinguishing different sedimentary types, ultimately determine the sedimentary facies.