Depositional Sedimentary Facies, Stratigraphic Control, Paleoecological Constraints, and Paleogeographic Reconstruction of Late Permian Chhidru Formation (Western Salt Range, Pakistan)

The Upper Indus Basin, in Pakistan’s western Salt Range, is home to the Zaluch Gorge. The sedimentary rocks found in this Gorge, belonging to the Chhidru Formation, were studied in terms of sedimentology and stratigraphy, and provide new insights into the basin paleogeographic evolution from the Precambrian to the Jurassic period. Facies analysis in the Chhidru Formation deposits allowed the recognition of three lithofacies (the limestone facies—CF1, the limestone with clay interbeds facies—CF2, and the sandy limestone facies—CF3) with five microfacies types (mudstone biomicrite—MF-1, wackestone-biomicrite—MF-2, wackestone-biosparite—MF-3, pack-stone-biomicrite—MF-4, and packstone-biosparite—MF-5), as well as their depositional characteristics. The identified carbonate and siliciclastic formations display various facies in a shallow marine environment, with different lithologies, sedimentary features, and energy conditions. It is thought that the depositional characteristics of these microfacies are closer to those of the middle to outer shelf. Because of the progressively coarsening outcrop sequence, this formation seems to be at the very top of the high stand system tract (HST). A modified dynamic depositional model of the Chhidru Formation is further built using outcrop data, facies information, and stratigraphy. According to this concept, the formation was deposited in the middle to inner shelf area of the shallow marine environment, during the Late-Permian period. The Permo-Triassic Boundary (PTB), which is the end of the type-1 series, is marked by this formation’s top.

The Capability of Sentinel-MSI (2A/2B) and Landsat-OLI (8/9) for Seagrass and Algae Species Differentiation using Spectral Reflectance

This paper assesses the reflectance difference values between the homologous visible and near-infrared (VNIR) spectral bands of Sentinel-MSI-2A/2B and Landsat-OLI-8/9 sensors for seagrass, algae, and mixed species discrimination and monitoring in a shallow marine environment southeastern of Bahrain in the Arabian Gulf. To achieve these, a field survey was conducted to collect samples of seawater, underwater sediments, seagrass (Halodule uninebell.netrvis and Halophila stipulacea) and algae (green and brown). As well, an experimental mode was established in a Goniometric-Laboratory to simulate the marine environment, and spectral measurements were performed using an ASD spectroradiometer over each separate and different case of seagrass and algae mixed species at different coverage rate (0, 10, 30, 75, and 100 %) considering the bottom sediments with clear and dark colors. All measured spectra were analyzed and transformed using continuum-removed reflectance spectral (CRRS) approach to assess spectral separability among separate or mixed species at varying coverage rates. Afterward, the spectra were resampled and convolved in the solar-reflective spectral bands of MSI and OLI sensors and converted into water vegetation indices (WVI) to investigate the potential of red, green, and blue bands for seagrass and algae species discrimination. For comparison and sensor differences quantification, statistical fits (p < 0.05) were conducted between reflectances in homologous bands and also between homologous WVI; as well as the coefficient of determination (R2) and root mean square difference (RMSD) were calculated. The results of spectral and CRRS analyses highlighted the importance of the blue, green, and NIR wavelengths for seagrass and algae detection and probable discrimination based on hyperspectral measurements. However, when resampled and convolved in MSI and OLI bands, spectral information loses the specific and unique absorption features and becomes more generalized and less precise. Therefore, relying on the multispectral bandwidth of MSI and OLI sensors, it is difficult or even impossible to differentiate or to map seagrass and algae individually at the species level. Additionally, instead of the red band, the integration of the blue or the green bands in WVI increases their discriminating power of submerged aquatic vegetation (SAV), particularly Water Adjusted Vegetation Index (WAVI), Water Enhance Vegetation Index (WEVI), and Water Transformed Vegetation Index (WTDVI) indices. These results corroborate the spectral analysis and the CRRS transformations that the blue and green electromagnetic radiation allows better marine vegetation differentiation. However, despite the power of blue wavelength to penetrate deeper into the water, it also leads to a relative overestimation of dense SAV coverage due to the higher scattering in this part of the spectrum. Furthermore, statistical fits between the reflectance in the VNIR homologous bands of SMI and OLI revealed excellent linear relationships (R2 of 0.999) with insignificant RMSD (≤ 0.0015). Important agreements (0.63 ≤ R2 ≤ 0.96) were also obtained between homologous WVI regardless of the integrated spectral bands (i.e., red, green, and blue), yielding insignificant RMSD (≤ 0.01). Accordingly, these results pointed out that MSI and OLI sensors are spectrally similar, and their data can be used jointly to monitor accurately the spatial distribution of SAV and its dynamic in time and space in shallow marine environment, provided that rigorous data pre-processing issues are addressed.

Foraminifera biostratigraphy and paleoenvironmental studies of well-x, eastern Niger delta

Ditch cutting samples from Well-X drilled in the Eastern part of the Niger delta were subjected to biostratigraphy and paleoenvironmental studies using micropaleontological analysis to identify the foraminifera present in the sections penetrated by the well.A total of 50 (fifty) foraminifera species made up of benthonic and planktic spp were recovered from the sections. The marker species identified are Globorotalia acostaensis, Globorotalia mernadii cultrate, Neogloboquadrina dutertrei, Globorotalia plesiotumida, Globorotalia obesa, Globorotalia nepenthes, Sphaeroidinella subdehiscens, Neogloboquadrina dutertrei, Globigerinoides sudquadratus.The four (4) biozones identified are N16 (Late Miocene 9.5Ma - 10.9Ma), N15-N14, N13-N12 and N12-N11 (Middle Miocene with corresponding ages 10.9Ma -11.8Ma, 11.8Ma-12.2Ma and 12.2Ma respectively).Using the encountered benthonic foraminiferal species, the paleoecology was determined; and it was revealed that the paleoenvironment of the section ranges from Inner Neritic to Outer Neritic Environment. Also, the lithological analysis revealed an intercalation of Shale, Mudstone and Sand which indicates various paleoecological episodes that led to their deposition.The age of the well was inferred from the bioevents of the marker species to be Middle Miocene to Late Miocene with the sparse occurrence of the Calcareous Benthic and the Plankonic species suggesting a shallow marine environment.

Organism motility in an oxygenated shallow-marine environment 2.1 billion years ago

Evidence for macroscopic life in the Paleoproterozoic Era comes from 1.8 billion-year-old (Ga) compression fossils [Han TM, Runnegar B (1992) Science 257:232–235; Knoll et al. (2006) Philos Trans R Soc Lond B 361:1023–1038], Stirling biota [Bengtson S et al. (2007) Paleobiology 33:351–381], and large colonial organisms exhibiting signs of coordinated growth from the 2.1-Ga Francevillian series, Gabon. Here we report on pyritized string-shaped structures from the Francevillian Basin. Combined microscopic, microtomographic, geochemical, and sedimentologic analyses provide evidence for biogenicity, and syngenicity and suggest that the structures underwent fossilization during early diagenesis close to the sediment–water interface. The string-shaped structures are up to 6 mm across and extend up to 170 mm through the strata. Morphological and 3D tomographic reconstructions suggest that the producer may have been a multicellular or syncytial organism able to migrate laterally and vertically to reach food resources. A possible modern analog is the aggregation of amoeboid cells into a migratory slug phase in cellular slime molds at times of starvation. This unique ecologic window established in an oxygenated, shallow-marine environment represents an exceptional record of the biosphere following the crucial changes that occurred in the atmosphere and ocean in the aftermath of the great oxidation event (GOE).