ALBERT

Description: Redox-sensitive elements (Mo, V, U, Re, Cd, Co, As, Sb, Tl, Ni, Cr, Mn, Fe, Pb, Cu, Zn, Se) and proxies for detrital clastic sedimentation (Al, Ti, Sc, Th) along with total organic carbon (TOC) and total sulfur (TS) were analysed to constrain the paleoredox conditions of the Middle-Upper Jurassic black shales in the Blue Nile (Abay) Basin, Ethiopia. These samples were collected from the deep marine Antalo Limestone (Oxfordian-Kimmeridgian), Gohatsion Formation (Bathonian) and glauconitic shale-mudstone unit (Aalenian-Toarcian). Significant variations in redox-sensitive elements concentration within and between these shales were evident for variable redox conditions. In general, the concentration of proxies for detrital clastic sedimentation increases from the Antalo Limestone to Gohatsion Formation and further to glauconitic shale-mudstone unit shales, respectively. The Antalo Limestone shales show slightly higher enrichment in redox-sensitive elements than the Gohatsion Formation and glauconitic shale-mudstone unit shales. The Antalo Limestones shales have higher TOC content than the glauconitic shale-mudstone unit shales and become very low in the Gohatsion Formation shales. The TS content in contrast, is relatively lower in the Antalo Limestone shales, intermediate in the Gohatsion Formation shales and becomes higher in the glauconitic shale-mudstone unit shales. The Antalo Limestone shales were deposited under anoxic-suboxic conditions whereas the Gohatsion Formation and glauconitic shale-mudstone unit shales were deposited under suboxic-oxic conditions. The TOC content and redox conditions of the Antalo Limestone shales implies favourable organic matter preservation and future source rock explorations in the basin should be targeted there.

Description: The aim of this work is to evaluate the genesis and tectonic setting of the Kenticha rare metal granite-pegmatite deposit using petrography and whole-rock geochemical analysis. The samples were analysed for major elements, and trace and rare earth elements by ICP-AES and ICP-MS, respectively. The Kenticha rare metal granite-pegmatite deposit is controlled by the N-S deep-seated normal fault that allow the emplacement of the granite-pegmatite in the study area. Six main mineral assemblages have been identified: (a) alaskitic granite (quartz + microcline + albite with subordinate muscovite), (b) aplitic layer (quartz + albite), (c) muscovite-quartz-microcline-albite pegmatite, (d) spodumene-microcline-albite pegmatite, partly albitized or greisenized, (e) microcline-albite-green and pink spodumene pegmatite with quartz-microcline block, which is partly albitized and greisenized, and (f) quartz core. This mineralogical zonation is also accompanied by variation in Ta ore concentration and trace and rare earth elements content. The Kenticha granite-pegmatite is strongly differentiated with high SiO2 (72–84 wt %) and enriched with Rb (∼689 ppm), Be (∼196 ppm), Nb (∼129 ppm), Ta (∼92 ppm) and Cs (∼150 ppm) and depleted in Ba and Sr. The rare earth element (REE) patterns of the primary ore zone (below 60 m depth) shows moderate enrichment in light REE ((La/Yb)N = ∼8, and LREE/HREE = ∼9.96) and negative Eu-anomaly (Eu/Eu* = ∼0.4). The whole-rock geochemical data display the Within Plate Granite (WPG) and syn-Collisional Granite (syn-COLG) suites and interpret as its formation is crustal related melting. The mineralogical assemblage, tectonic setting and geochemical signatures implies that the Kenticha rare metal bearing granite pegmatite is formed by partial melting of metasedimentary rocks during post-Gondwana assembly and further tantalite enrichment through later hydrothermal-metasomatic processes.

Description: This study aims to evaluate the hydrogeochemical and isotopic signatures of water (surface and groundwater) of the Andasa watershed in the upper Blue Nile Basin, northwest Ethiopia using integrated hydrogeochemical and isotopic methods with the help of Hierarchical Cluster Analysis (HCA) and Principal Component Analysis (PCA) techniques. To achieve this, major cation and anion (n = 61) and stable isotope (δ2H and δ18O; n = 36) analyses have been done. The result revealed that geogenic (rock-water interaction) and anthropogenic (waste disposal landfill site, agricultural practices, diverted river via open canal) effects are the major water quality controlling factors. Rock-water interaction is more dominant factor that produced alkaline earths bicarbonate hydrogeochemical facies. Moreover, the Cl and δ18O relationship shows a shift towards the right from vertical axis (δ18O) which signifies anthropogenic effects. Using HCA and PCA techniques, EC, TDS, Ca, Na, Mg, HCO3, SO4, Cl and NO3 were identified as the leading hydrogeochemical parameters in determining the area. Accordingly, Mg-Ca-HCO3, Ca-Mg-HCO3 and Ca-Na-HCO3 found to be the main water types. Silicate minerals are responsible for controlling the hydrogeochemical property of the waters in the area through hydrolysis and cation exchange processes. Most of the samples signify evaporation prior to recharge in the wet seasons and irrigation return flow in the dry seasons. Most river samples show depleted δ18O and δ2H reflecting that their source is highland area of the watershed. From hydrogeochemical and isotopic signatures, the north and northeast parts of the area are the discharging zones and southern and central parts are the recharging zones.

Description: High-quality 3D seismic data are used to analyze the history of fault growth and hydrocarbon leakage in the Snøhvit Field, Southwestern Barents Sea. The aim of this work is to evaluate tectonic fracturing as a mechanism driving hydrocarbon leakage in the study area. An integrated approach was used which include seismic interpretation, fault modeling, displacement analysis and multiple seismic attribute analysis. The six major faults in the study area are dip-slip normal faults which are characterized by complex lateral and vertical segmentation. These faults are affected by three main episodes of fault reactivation in the Late Jurassic, Early Cretaceous and Paleocene. Fault reactivation in the study area was mainly through dip-linkage. The throw-distance plots of these representative faults also revealed along-strike linkage and multi-skewed C-type profiles. The faults evolved through polycyclic activity involving both blind propagation and syn-sedimentary activity with their maximum displacements recorded at the reservoir zone. The expansion and growth indices provided evidence for the interaction of the faults with sedimentation throughout their growth history. Soft reflections or hydrocarbon-related high-amplitude anomalies in the study area have negative amplitude, reverse polarity and are generally unconformable with structural reflectors. The interpreted fluid accumulations are spatially located at the upper tips of the major faults and gas chimneys. Four episodes of fluid migration are inferred and are linked to the three phases of fault reactivation and Neogene glaciations. Hydrocarbon leakage in the Snøhvit Gas Field is driven by tectonic fracturing, uplift, and erosion. The interpreted deep-seated faults are the main conduits for shallow hydrocarbon accumulations observed on seismic profiles.

Description: This work aims to unravel the provenance, depositional tectonic setting and source area weathering of the cretaceous Debre Libanos Sandstone in the Blue Nile Basin, Ethiopia from its petrographic and geochemical signatures. Both the average chemical index of alteration (CIA) and chemical index of weathering (CIW) of sandstones (CIA = 91.08, CIW = 96.75), shales (CIA = 81.89, CIW = 98.17) and siltstones (CIA = 98.10, CIW = 99.35) of the Debre Libanos Sandstone indicate very strong chemical weathering. The low Th/Sc ratio of sandstones (1.46), shales (0.85) and siltstones (0.81), and Th/Sc versus Zr/Sc relationship indicate sediment recycling that leads to a progressive enrichment of heavy minerals such as zircon which is the major host for Zr and Th. The increase of quartz content in sandstones and dense minerals in siltstones and shales can be related to hydraulic sorting, grain-size controlled fractionation and source composition. Trace element concentration and their ratios (La/Th, Cr/Th, Th/Sc, Cr/V, Y/Ni) with rare earth element proxies (Eu/Eu*, LaN/YbN) of the studied samples revealed felsic to mixed source rocks of upper continental crust with some input from recycled old sediments. The source area of the Debre Libanos Sandstone is from the northern and northwestern Ethiopia during the time of marine regression, retreat of the Indian Ocean from NW Ethiopia back to SE Somalia. Tectonic discrimination diagrams revealed continental rift setting for the sandstones and collision setting for shales and most of the siltstones. Furthermore, the studied sandstones were partly deposited in a passive margin setting which had undergone post-depositional K-metasomatic alteration. The shales and siltstones were deposited in active margin setting.

Description: This study investigates the hydrocarbon generation potential, kerogen quality, thermal maturity and depositional environment of Middle – Upper Jurassic sedimentary rocks in the Blue Nile Basin, Ethiopia, using organic petrography, Rock‐Eval pyrolysis and molecular organic geochemistry. Thirty‐seven outcrop samples were analysed for their total organic carbon (TOC) and inorganic carbon (TIC) contents. The samples came from a Toarcian – Bathonian transitional glauconitic shale‐mudstone unit, the overlying Upper Bathonian Gohatsion Formation, and the Lower Callovian – Upper Tithonian Antalo Limestone Formation. Thirteen samples with sufficient TOC contents for further analysis of the organic matter, eight from the Antalo Limestone Formation and five from the glauconitic shale‐mudstone unit, were selected and analysed using Rock‐Eval pyrolysis. Vitrinite reflectance (VRr) was measured on random particles, and qualitative maceral analysis was performed under normal incident and UV light. Nine samples were selected for molecular organic‐geochemical analyses. All the samples originating from the Gohatsion Formation showed TOC values which were too low for further analyses of the organic matter. The TOC contents of shales and limestones from the Antalo Limestone Formation and and of shales from the glauconitic shale‐mudstone unit were 3.43‐6.43% (average 4.85%) and 0.76‐3.15% (average 1.72%), respectively, and two coaly shale samples from the latter unit have average TOC values of 18.48%. HI values are very high for shales in the Antalo Limestone Formation (average 575 mg HC/g TOC) but lower for the shales in the glauconitic shale‐mudstone unit. The vitrinite reflectance of shales from the Antalo Limestone Formation ranged between 0.21% and 0.47%; coaly shales from the glauconitic shale‐mudstone unit have VRr% of between 0.29% and 0.35%. Pr/Ph ratios for samples of the Antalo Limestone Formation shales ranged from 0.8 to 1.1, indicating anoxic to suboxic depositional conditions; while shales in the glauconitic shale‐mudstone unit show higher values of up to 4.9. In terms of organic petrography, the Antalo Limestone Formation samples are dominated by finely dispersed liptinite particles and alginite; the organic material in the glauconitic shale‐mudstone unit is of higher land plant origin, with abundant vitrinite and inertinite. Sterane and hopane biomarker ratios suggest an anoxic/suboxic depositional environment for the Antalo Limestone Formation shales and limestones. These values together with Rock‐Eval Tmax (average 414 °C), the high ratio of pristane and phytane over the n‐alkanes C17 and C18, and hopane biomarker ratios indicate that the Middle – Upper Jurassic succession is of low thermal maturity in the central parts of the Blue Nile Basin. The Antalo Limestone Formation shales have a high petroleum generation potential, making them a viable target for future exploration activities.

Description: This study integrates the Revised Universal Soil Loss Equation (RUSLE) with GIS and remote sensing techniques to assess soil erosion severity in the Dembecha District, Northwestern Ethiopia. Digital elevation model (DEM), land use/land cover (LU/LC) maps, and rainfall and soil data were used as an input to identify the most erosion prone areas. Accordingly, the district was classified into five soil loss severity classes: very slight (24%), slight (49%), moderate (11%), severe (3%) and very sever (13%) risk classes. Most of the district was characterized by very slight to slight soil erosion rates which is associated with the gentle slope covered by Alisols and Cambisols. The mean annual soil loss in the district is estimated to be 49 t ha−1 yr−1, i.e. total soil loss of 526,996 t yr−1. Hence, soil and water conservation (SWC) measures should prioritize based on soil erosion severity levels.

Description: As in most disciplines of science, technology, engineering, mathematics and medicine (STEMM), gender disparity is prevalent in the ranking of Earth Sciences faculties at senior and advanced levels. (i.e., Associate and Full Professors). In this study, a robust database was mined, created, and analyzed to assess the faculty compositions of 142 Earth Science departments in 39 countries across Africa. The data were collected from verifiable online resources focusing on ranks and gender ratios within each department. The studied earth science departments cut across universities in northern, southern, central, eastern, and western Africa. Our data revealed that female faculty members are predominantly underrepresented in most of the departments documented and are markedly uncommon in senior positions such as Professors, associate Professors, and senior researchers compared to their male counterparts. On the contrary, female faculty members are predominant in the lower cadres, such as lecturers, teaching, and graduate assistants. The observed male to female ratio is 4:1. At the base of this gender gap is the lower enrolment of female students in Earth Science courses from undergraudate to graduate studies. To achieve gender equality in Earth Science faculty composition in Africa, we recommend increasing female students' enrollment, mentoring, awareness, timely promotion of accomplished female researchers, and formulation of enabling government policies. More work-related policies that guarantee work-life balance for female earth science academic professionals should be formulated to attract and retain more women into Earth Sciences careers.

Description: The Southern Permian Basin in Central Europe (in Germany and Poland) hosts several sediment-hosted Cu deposits (see Borg et al., 2012). The Cu- and Zn-Pb sulfide mineralization is preserved in the coarse-grained continental siliciclastics of the uppermost Rotliegend (S1), organic matter- and carbonate-rich marine mudstones of the Kupferschiefer (T1) and dolomitic Zechstein Limestone (Ca1). In these datasets, we provide quantitative mineralogical and geochemical data of drill core samples from the Saale Basin in East Germany. The samples include the uppermost Rotliegend sandstone (S1), Kupferschiefer (T1) and lowermost Zechstein Limestone (Ca1), referred as the Kupferschiefer system, from three drill cores (Sangerhausen, Allstedt and Wallendorf). This data publication includes quantitative mineralogy (X-ray diffraction), bulk rock major, minor and trace element geochemistry (X-ray fluorescence and inductively coupled mass spectrometry) and total organic carbon (elemental analyzer).