Physicochemical Parameters and Suitability for Irrigation of Groundwater Resources from Biskra Area (Southeastern Algeria)

This study is part of the more general framework for diagnosis of the quality of water resources in the Biskra area and its suitability for irrigation. This work reports the results of an analysis of physicochemical groundwater quality. Groundwater samples were collected from 12 boreholes in different aquifers exploited in the area, and used for drinking and domestic purposes. The results showed that the water of the limestone aquifer (Maastrichtian) is better than other aquifers (phreatic, Miopliocene, Lower Eocene). This affects more particularly the pH, conductivity (mineralization), total hardness, and concentration of the major elements. As far as the same aquifers (phreatic, Miopliocene, Lower Eocene), present water which classified mediocre highly mineralized for irrigation because EC > 2250 μS/cm (class 4). The Maastrichtian aquifer presents a poor water quality (class 3), according to the Riverside classification.

Lower Eocene (Middle Ilerdian) brachiopods from the Campo region, Central Pyrenees, north-eas tern Spain

Three brachiopod species, Terebratulina tenuistriata (Leymerie, 1846), Argyrotheca vidali (Mallada, 1878), and "Terebratula" n. sp., are recognized in the marls and calcareous silts of the Lower Eocene Puebla Formation of the Campo region in the Central Pyrenees, north-eastern Spain. The rich and well preserved material of T. tenuistriata and A. vidali allows to recognize the range of their morphological variability and to evaluate the status of earlier established species. The investigated assemblage is characterized by the small, pedunculate taxa adapted to life on a soft bottom anchoring directly in a soft substrate or attaching to very small, hard substrates.

Past ecosystems drive the evolution of the early diverged Symphyta (Hymenoptera: Xyelidae) since the earliest Eocene

Paleoxyela nearctica gen. et sp. nov., is described from the upper Eocene of Florissant Formation in Colorado. We placed Paleoxyela gen. nov. in the subfamily Macroxyelinae and the tribe Macroxyelini based on the numerous wing venation characters visible on the specimen. Proxyelia pankowskii gen. et sp. nov. is described from the lower Eocene Fossil Lake deposits of the Green River Formation in Wyoming. We placed Proxyelia gen. nov. in the subfamily Macroxyelinae and the tribe Xyeleciini based on the numerous wing venation characters visible on the specimen. These new records of the family Xyelidae are of particular importance to better understand the past diversity of the clade and propose hypotheses about their diversification. Extant Xyelidae inhabit temperate Northern Hemisphere forests, and most of their larvae feed on conifers, which may explain why they are relatively poorly diversified compared to the other symphytan families. We suggest that the global decline in conifers and the reduced diversity of extant host trees partly explain the diversity of extant Xyelidae. We correlate the biome repartition during the Eocene to that of the extant xyelid.

New hermit crabs (Paguroidea, Anomura) from the Eocene of Huesca, Spain

A new genus and two new species of fossil hermit crabs (Anomura, Paguroidea) are described from the southern Pyrenean basins (Huesca, NE Spain). Parapetrochirus nov. with P. robustus n. gen., n. sp., as type species, comes from the lower Eocene (Ypresian) Roda Formation. It preserves both chelipeds exhibiting a notable heterochely, a larger left cheliped and a concavity without granulation in the inner upper portions. Eocalcinus gerardbretoni n. sp. comes from the highest levels of the Arguis Formation (Priabonian) in Yeste locality. This species is characterized by a hemispherical outline and a sinuous lower margin of the chela, which differs from the type species of the genus. The cheliped morphology of such species allows inclusion in the families Diogenidae and Calcinidae, respectively. Fossil paguroids are relatively rare in the Eocene of Spain, therefore, the description of these two new taxa increases the known diversity of this group. Parapetrochirus robustus n. gen., n. sp. inhabited siliciclastic substrates within a prodelta environment and E. gerardbretoni n. sp. was collected from the last levels of coral rudstones just below the continental influence of Yeste-Arrés Formation.

Rare Earth Elements Enrichment in the Upper Eocene Tošići-Dujići Bauxite Deposit, Croatia, and Relation to REE Mineralogy, Parent Material and Weathering Pattern

Tošići-Dujići bauxite deposit, situated in Dalmatian inlands, Croatia, contains minor remaining bauxite reserves. The deposit lies on Lower Eocene foraminiferal limestone and is covered by Upper Eocene Promina sediments. Bauxite samples were analyzed for textural, mineralogical, and geochemical features in order to determine absolute REE abundances and their relation to mineralogy, as well as to devise the origin of REE enrichment and to trace weathering and bauxitization paths of the parent material. The samples show total REE abundances up to 3500 mg/kg with significant HREE enrichment in some cases. All samples are gibbsitic with hematite and anatase as major phases. Kaolinite occurs in most of the samples, and goethite, böhmite, and nordstrandite are minor phases. Monazite-(Ce) and xenotime-(Y) were identified as detrital REE minerals as well as authigenic florencite-(Ce). In the REE most abundant sample, REE are most likely bound to Fe- and Ti-oxide phases as suggested by correlation analysis. Chemical weathering proxies show intensive weathering. Geochemical and textural data imply that the REE enrichment is influenced by intensive weathering (CIA 97.87–99.26) of detrital material, and also by possible deposition/redeposition of residual material potentially derived and mobilized from various sedimentary rocks of the area.

Stratigraphic Lexicon: A revised guide to the Cenozoic Surface Formations of Qatar, Middle East (excluding the islands)

The author learned first-hand about the surface stratigraphy and geology of Qatar by dedicating most of his weekends to conducting field works and public-guided field tours from 2007 to 2020 while employed by Qatar Petroleum. Here, he reviews and updates the surface stratigraphic knowledge of Qatar since the last lexicon was published back in 1975. The geology and macro-paleontology of the Lower Eocene Rus, Middle Eocene Dammam, Lower Miocene Dam, and Mio-Pliocene Hofuf formations are described in detail and well-illustrated.

Sandstone body character, river styles, and geomorphology of the lower Eocene Willwood Formation, Bighorn Basin, Wyoming, USA

The lower Eocene Willwood Formation of the intermontane Bighorn Basin, Wyoming, USA, is an alluvial red bed succession with a sand content of ca. 20%-25%. The formation has been studied intensively for paleontology, paleoclimate, and sedimentary reconstruction. However, alluvial sandstone bodies and their corresponding river styles remain little characterized and documented. Here, efforts are made to study the characteristics and river styles of sandstone bodies through ca. 300 m of alluvial stratigraphy in the McCullough Peaks outcrop area based on the field data and a georeferenced 3-D photogrammetric model. Four channel facies associations are recognized, and they are ascribed to four river planform styles: distributary channel, massive trunk-shaped channel, braided channel, and sinuous channel, with the latter two styles being the more abundant. The channel sandstone bodies that show the character of sinuous rivers and those of braided rivers differ significantly in average thickness (6.1 m versus 9.0 m) and insignificantly in average width (on average 231 m) and paleoflow directions (on average N003). Braided-character dominated and sinuous-character dominated river styles are seen to alternate in the outcrop, while they show no spatial dependency in the 10 km2 study area. Bighorn Basin margins varied in the early Eocene, with differing tectonic, geological, and topographic characteristics. The observed mixture of river styles may be attributed to differential influences of axial and transverse river systems and/or climate change that controls water discharge and sediment load. An early Eocene geomorphologic reconstruction is constructed summarizing these new and earlier results.