Los mármoles cálcicos de El Escorial (Complejo Metamórfico Cushamen, Macizo Norpatagónico): caracterización isotópica de 87Sr-86Sr y edad de sedimentación

The El Escorial marbles (Cushamen Metamorphic Complex) along with amphibolites form metamorphic septa within the permian granitoids of the Mamil Choique Formation (261-286 Ma). The metamorphism, determined in granulite facies migmatic gneisses septa cropping out 120 km southwest of El Escorial, occurs at 311 ± 27 Ma (CHIME method in monazite). The marbles are calcitic (calcite > 95%, R.I.: 0.5 to 2.5%) and show 87Sr/86Sr values between 0.70768 and 0.70825 (n = 10). The data provided in this work, added to previous contributions, allow to constraints the sedimentation age of the silicic-carbonate successions of the Cushamen Metamorphic Complex between ca. 385 and 335 Ma. This suggests the existence of a mixed carbonate-siliciclastic platform at least in the southernmost portion of southwestern Gondwana between Middle Devonian and early Carboniferous (Middle Mississippian).

LiCoO2/Graphite Cells with Localized High Concentration Carbonate Electrolytes for Higher Energy Density

Widening the working voltage of lithium-ion batteries is considered as an effective strategy to improve their energy density. However, the decomposition of conventional aprotic electrolytes at high voltage greatly impedes the success until the presence of high concentration electrolytes (HCEs) and the resultant localized HCEs (LHCEs). The unique solvated structure of HCEs/LHCEs endows the involved solvent with enhanced endurance toward high voltage while the LHCEs can simultaneously possess the decent viscosity for sufficient wettability to porous electrodes and separator. Nowadays, most LHCEs use LiFSI/LiTFSI as the salts and β-hydrofluoroethers as the counter solvents due to their good compatibility, yet the LHCE formula of cheap LiPF6 and high antioxidant α-hydrofluoroethers is seldom investigated. Here, we report a unique formula with 3 mol L−1 LiPF6 in mixed carbonate solvents and a counter solvent α-substituted fluorine compound (1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropylether). Compared to a conventional electrolyte, this formula enables dramatic improvement in the cycling performance of LiCoO2//graphite cells from approximately 150 cycles to 1000 cycles within the range of 2.9 to 4.5 V at 0.5 C. This work provides a new choice and scope to design functional LHCEs for high voltage systems.

An Attempt for Construction of Carbonate Platform Geometry from Devonian Hajigak Formation, Central Afghanistan, with the Help of Facies Analysis and Petrography

The subject of sedimentology fundamentally remained subdivided into two sectors viz. siliciclastic and carbonate with the understanding that these two systems are mutually dissociative in terms of their genesis. Even in the highly referred textbooks, siliciclastics and carbonates are always discussed in separate sections. Presumably, the limited occurrences of mixed siliciclastic-carbonate sediments in nature are because of constraining effects that siliciclastics have on carbonate-secreting organisms; the two sediments rarely found mutually associated in nature. Although the mixed carbonate-siliciclastic sediments are subordinate in occurrence, their presence in some instances proved that they do not represent any geological oddity. Rather, their sediment logical history may tell us a great deal about the dynamics and interactions of facies, paleoecologies of many carbonate-secreting organisms, and tectonic histories of depositional basins. Keeping this in mind, the present study attempted to recognize and draw the paleoenvironmental conditions and processes of the Devonian Hajigak Formation, Afghanistan by means of detailed facies analysis and petrographical signatures. An attempt has also been made to characterize sandstone wedges that punctuate the carbonate succession and some variable deposits of shales and marls.

The Franklinian Composite Tectono-Sedimentary Element, North Greenland

The Franklinian margin composite tectono-sedimentary element (CTSE) in North Greenland is dominated by Neoproterozoic - lowermost Devonian sedimentary strata that include early syn-rift through passive margin TSEs of mixed carbonate and siliciclastic facies. The sedimentary successions are well exposed in much of northern Greenland, but locally were strongly affected by the Ellesmerian Orogeny, resulting in a fold and thrust belt that deformed the northernmost exposures. An exposed palaeo-oilfield attests to the petroleum potential of the basin. Several formations have good source potential and several others have good reservoir properties. Palaeo-heat flow indicators show that temperatures increase to the north, where much of the basin is over-mature. Because of the remoteness of the area and the restricted locations where petroleum potential is likely to remain, the basin is not currently a target for exploration.

Detailed Lithofacies and Architectural Facies Analyses on Mixed Carbonate-Siliciclastic Clastic Shoreline Depositional Environment of the Cibulakan Formation in Cipamingkis River, Jonggol, Bogor, West Java

Cibulakan Formation as one of the prolific hydrocarbon-bearing intervals has become an interesting study object for many researchers. The continuous outcrop of the Cibulakan Formation in the Cipamingkis River comprises claystone, sandstone, and subordinate limestone of grainstone, packstone, and wackestone facies. The outcrop should be able to give a clearer vertical and spatial variation of sandstone and limestone geometry compared to the conventional core alone. Field observations followed by measuring the section is conducted to distinguish lithofacies and to create a stratigraphic profile from the chosen interval. Samples and thin sections from sandstone and limestone lithofacies are observed further to determine fragment type variation, matrix, cement, texture, and porosity types qualitatively. Fourteen (14) lithofacies have been recognized from the observation, i.e., Slumped Sandstone (A1), Claystone (A2), Slightly-bioturbated Sandstone (B1), Cross-laminated Sandstone (B2), Parallel-laminated Siltstone (B3), Calcareous Claystone (B4), Moderately-bioturbated Sandstone (C1), Hummocky Cross-stratified Sandstone (C2), Skeletal – Coral clast Wackestone (C3), Skeletal-clast Packstone (C4), Coralline Foraminiferal Boundstone (C5), Low-angle Planar Cross-bedded Sandstone (D1), Intensely-bioturbated Sandstone (D2), and Trough Cross-bedded Sandstone (D3). There are four architectural facies in the research interval and each of them is composed of different and specific lithofacies. An ideal parasequence is composed of all Architectural Facies namely : (A) Offshore-Transition (B) Lower Shoreface (C) Upper Shoreface with the whole thickness range between 15 to 25 m and the parasequence shows thickening upward succession. The detailed information about the lithofacies and architectural facies hopefully will provide a better understanding of the facies modelling of the mixed carbonate-siliciclastic depositional setting, new insights for parasequence recognition in clastic shoreline depositional environment and become a reference for other areas lacking in core data and/or outcrop analogue.