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In southern Africa, the Okavango Delta is a large alluvial fan sustaining a unique wetlands ecosystem in the heart of the Kalahari desert. The Delta is fed by an annual flood that brings water from the Angolan plateaus to the north, down to the Okavango region. The fan is characterized by vegetated, permanent or seasonal floodplains, dotted with thousands of sandy islands of various origin (inverted paleo‐channels, paleo‐dunes, meander bars, etc). On at least some of these islands, shallow groundwater is characterized by a high pH (>8) and a high concentration of metals and metalloids, making it naturally toxic. In the 1990s, McCarthy and co‐workers explain the chemistry of that water through an evapotranspiration model, the flood‐water being pumped by the vegetation toward the center of the islands and progressively enriched in elements by evapotranspiration. This model has been widely applied to all islands in the Okavango, not considering their individual specificities nor that of the surrounding floodplain. Our work, based on a multidisciplinary approach including sedimentology, mineralogy and geochemistry, and discussed by McCarthy and Humphries, questions the established model suggesting that the alkaline water cannot derive from simple concentration of the floodwater. Key Points: The chemical composition of the alkaline groundwater cannot reflect simple evaporation processesThe variable origin of islands in the Okavango Delta makes for variable bio‐geochemical processesThe hydro‐geochemical functioning of the Delta will only be understood through interdisciplinary studies [ABSTRACT FROM AUTHOR]

The Grand Forks complex (GFC) is a metamorphic core complex within the composite Shuswap complex in the southern Omineca belt of the Canadian Cordillera. It is juxtaposed against the surrounding low-grade rocks of the pericratonic Quesnel terrane by outward-dipping Eocene normal faults. The GFC attained peak metamorphic conditions of 750-800 °C and 5.5-6.0 kbar (1 kbar = 100 MPa) in the late Paleocene to early Eocene, followed by ~2.5 kbar of near- isothermal decompression at upper-amphibolite to granulite facies conditions (~725-750 °C) in the early Eocene. Subsequent low-temperature greenschist-facies exhumation (~0.7-1.5 kbar) was accommodated by the brittle--ductile Kettle River normal fault (KRF) on the east flank of the complex and the Granby fault (GF) on the west flank. This study presents 16 new [sup.40]Ar/[sup.39]Ar hornblende and biotite dates from the GFC and low-grade rocks in the hanging walls to the KRF and GF. Cooling of the GFC through the closure temperature of hornblende (~530 °C) is constrained to the interval between ~54 and 51.4 ± 0.5 Ma, whereas cooling through the closure temperature of biotite (~280 °C) occurred at 51.4 ± 0.2 Ma. In the hanging wall of the KRF, cooling through the closure temperature of hornblende and biotite occurred nearly coevally at 51.7 ± 0.6 Ma and 51.0 ± 1.0 Ma, respectively. Five apatite fission track dates (closure temperature ~110 °C) from the GFC and adjacent hanging walls are indistinguishable within error, yielding an average age of 34.6 ± 2.0 Ma. The lack of difference in biotite and apatite ages between the GFC and the low-grade hanging wall rocks against which it is juxtaposed suggests no significant movement on the KRF and GF after ca. 51 Ma. Results from this study and a previous study on U-- Pb dating of the GFC document rapid cooling of the GFC in excess of 200 °C/Ma ina4Ma interval between 55 and 51 Ma (Eocene). This rapid phase of exhumation of the GFC was followed by 15 Ma of slow cooling (~10 °C/Ma) of the joined GFC and hanging wall between ~280 °C (biotite closure) and ~110 °C (apatite closure). Resume : Le complexe de Grand Forks (GFC) est un complexe a noyau metamorphique a l'interieur du complexe composite de Shuswap dans le sud de la ceinture Omineca de la cordillere canadienne. Il est juxtapose aux roches environnantes, de faible metamorphisme, du terrane pericratonique de Quesnel par des failles normales a pendage vers l'exterieur, datant de l'Eocene. Le GFC a atteint des conditions metamorphiques de crete de 750-800 °C et de 5,5-6,0 kbar (1 kbar = 100 MPa) entre le Paleocene tardif et l'Eocene precoce; ces conditions ont ete suivies d'une decompression quasi isotherme a ~2,5 kbar sous des conditions de facies superieur des amphibolites au facies des granulites (~725-750 °C) a l'Eocene precoce. Par la suite, une exhumation a basse temperature, au facies des schistes verts (~0,7-1,5 kbar), a ete aide par la faille normale cassante-ductile de Kettle River (KRF) sur le flanc est du complexe et par la faille Granby (GF) sur le flanc ouest. Cette etude presente 16 nouvelles datations [sup.40]Ar/[sup.39]Ar sur une hornblende et une biotite du GFC et des roches a faible metamorphisme de l'eponte superieure du KRF et du GR. Le refroidissement du GFC jusqu'a la temperature de fermeture de la hornblende (~530 °C) est limite a l'intervalle entre ~54 et 51,4 ± 0,5 Ma, alors que le refroidissement jusqu'a la temperature de fermeture de la biotite (~280 °C) a eu lieu il y a 51,4 ± 0,2 Ma. Dans l'eponte superieure de la faille Kettle River, le refroidissement jusqu'a la temperature de fermeture de la hornblende et de la biotite s'est produit presque simultanement, soit respectivement a 51,7 ± 0,6 Ma et 51,0 ± 1,0 Ma. Cinq datations obtenues par traces de fission sur l'apatite (temperature de fermeture ~110 °C) provenant du GFC et des epontes superieures adjacentes sont indistinguables a l'interieur de la marge d'erreur, donnant une moyenne de 34,6 ± 2,0 Ma. Le manque de difference dans les ages de la biotite et de l'apatite entre le GFC et les epontes superieures des roches a faible metamorphisme auxquelles ils sont juxtaposes suggererait qu'aucun mouvement significatif ne s'est produit le long de la faille Kettle River et la faille Grangy apres 51 Ma. Selon les resultats de la presente etude et d'une etude anterieure portant sur la datation U-Pb du GFC, un refroidissement rapide du GFC a plus de 200 °C/Ma serait survenu dans un intervalle de 4 Ma entre 55 et 51 Ma (Eocene). Cette phase rapide d'exhumation du GFC a ete suivie de 15 Ma de refroidissement lent (~10 °C/Ma) de l'ensemble GFC et l'eponte superieure entre ~280 °C (fermeture de la biotite) et ~110 °C (fermeture de l'apatite). [Traduit par la Redaction], Introduction The Grand Forks complex (GFC) is a north-south-trending, fault-bounded metamorphic core complex straddling the border between southern British Columbia and northern Washington State (Fig. 1). It is known as [...]

Abstract Background Malaria remains a major public health problem in the Republic of Congo, with Plasmodium falciparum being the deadliest species of Plasmodium in humans. Vector transmission of malaria is poorly studied in the country and no previous report compared rural and urban data. This study aimed to determine the Anopheles fauna and the entomological indices of malaria transmission in the rural and urban areas in the south of Brazzaville, and beyond. Methods Indoor household mosquitoes capture using electric aspirator was performed in rural and urban areas during raining and dry seasons in 2021. The identification of Anopheles species was done using binocular magnifier and nested-PCR. TaqMan and nested-PCR were used to detect the Plasmodium species in the head/thorax and abdomens of Anopheles. Some entomological indices including the sporozoite infection rate, the entomological inoculation rate and the man biting rate were estimated. Results A total of 699 Anopheles mosquitoes were collected: Anopheles gambiae sensu lato (s.l.) (90.7%), Anopheles funestus s.l. (6.9%), and Anopheles moucheti (2.4%). Three species of An. gambiae s.l. were identified including Anopheles gambiae sensu stricto (78.9%), Anopheles coluzzii (15.4%) and Anopheles arabiensis (5.7%). The overall sporozoite infection rate was 22.3% with a predominance of Plasmodium falciparum, followed by Plasmodium malariae and Plasmodium ovale. Anopheles aggressiveness rate was higher in households from rural area (1.1 bites/night) compared to that from urban area (0.8 ib/p/n). The overall entomological inoculation rate was 0.13 ib/p/n. This index was 0.17 ib/p/n and 0.092 ib/p/n in rural and in urban area, respectively, and was similar during the dry (0.18 ib/p/n) and rainy (0.14 ib/p/n) seasons. Conclusion These findings highlight that malaria transmission remains high in rural and urban area in the south of Republic of Congo despite the ongoing control efforts, thereby indicating the need for more robust interventions.

[1] The present-day topography of the Tian Shan range is considered to result from crustal shortening related to the ongoing India-Asia collision that started in the early Tertiary. In this study we report evidence for several episodes of localized tectonic activity which occurred prior to that major orogenic event. Apatite fission track analysis and (U-Th)/He dating on apatite and zircon indicate that inherited Paleozoic structures were reactivated in the late Paleozoic-early Mesozoic during a Cimmerian orogenic episode and also in the Late Cretaceous-Paleogene (around 65 60 Ma). These reactivations could have resulted from the accretion of the Kohistan-Dras arc or lithospheric extension in the Siberia-Mongolia zone. Activity resumed in the late Mesozoic prior to the major Tertiary orogenic phase. Finally, the ongoing deformation, which again reactivates inherited tectonic structures, tends to propagate inside the endoreic basins that were preserved in the range, leading to their progressive closure. This study demonstrates the importance of inherited structures in localizing the first increments of the deformation before it propagates into yet undeformed areas. Citation: Jolivet, M., S. Dominguez, J. Charreau, Y. Chen, Y. Li, and Q. Wang (2010), Mesozoic and Cenozoic tectonic history of the central Chinese Tian Shan: Reactivated tectonic structures and active deformation, Tectonics, 29, TC6019, doi: 10.1029/2010TC002712.

Apatite fission track analysis (AFTA) data are used to bring new light on the long-term and recent history of the Baikal rift region (Siberia). We describe the evolution of the topography along a NW--SE profile from the Siberian platform to the Barguzin range across the Baikal southern Patom range and the northern termination of Lake Baikal. Our results show that the Baikal-Patom range started to form in the Early Carboniferous and was reactivated in Middle Jurassic--Lower Cretaceous times during the orogenic collapse of the Mongol-Okhotsk belt. Samples located in the Siberian platform recorded a continuous sedimentation up to the early Carboniferous but remain unaffected by later tectonic episodes. The Barguzin basin probably started to form as early as Late Cretaceous, suggesting a continuum of deformation between the postorogenic collapse and the opening of the Baikal Rift System (BRS). The initial driving mechanism for the opening of the BRS is thus independent from the India-Asia collision. AFTA show a late Miocene--early Pliocene increase in tectonic extension in the BRS that confirms previous thoughts and might reflect the first significant effect of the stress field generated by the India-Asia collision. doi:10.1029/2008TC002404.

[1] We studied the patterns, rates and evolution of fluvial terraces and fault system during the building process of an intracontinental transpressional mountain in the Gobi-Altay (Mongolia). By analyzing incisions and offsets of fluvial terraces and alluvial fans, we show that the massif has grown by outward migration of thrust faults through time. On the northern flank, the present bounding thrust fault began its activity ~600 ka ago, while a more internal sub-parallel fault was still active until ~200-100 ka. Vertical offset of an alluvial fan abandoned ~100 ka ago allows an estimate of 0.1 mm/yr Upper Pleistocene--Holocene uplift rate. The morphology of the catchment-piedmont system strongly suggests a periodical formation of the alluvial surfaces, controlled by the climatic pulses, at the beginning of the wet interglacial periods. The abandonment of the alluvial terraces lags by several thousand years the abandonment of the alluvial fans, showing a diachronous incision propagating upstream. The incision rate deduced from the different elevations of straths exceeds of one order of magnitude the rock uplift rate. This excess is mostly due to ongoing drainage network growth at the core of the massif, and incision due to alluvial apron entrenchment near the outlet. This implies that fluvial response is mainly controlled by drainage growth, interaction with piedmont and cyclic climatic variations, rather than by rock uplift. Citation: Vassallo, R., et al. (2007), Transpressional tectonics and stream terraces of the Gobi-Altay, Mongolia, Tectonics, 26, TC5013, doi: 10.1029/2006TC002081.

Abstract Background Although Plasmodium falciparum infection is largely documented and this parasite is the main target for malaria eradication, other Plasmodium species persist, and these require more attention in Africa. Information on the epidemiological situation of non-P. falciparum species infections is scarce in many countries, including in the Democratic Republic of the Congo (hereafter Republic of the Congo) where malaria is highly endemic. The aim of this study was to determine the prevalence and distribution of non-P. falciparum species infections in the region south of Brazzaville. Methods A cross-sectional survey was conducted in volunteers living in rural and urban settings during the dry and rainy seasons in 2021. Socio-demographic and clinical parameters were recorded. Plasmodium infection in blood samples was detected by microscopic analysis and nested PCR (sub-microscopic analysis). Results Of the 773 participants enrolled in the study, 93.7% were from the rural area, of whom 97% were afebrile. The prevalence of microscopic and sub-microscopic Plasmodium spp. infection was 31.2% and 63.7%, respectively. Microscopic Plasmodium malariae infection was found in 1.3% of participants, while sub-microscopic studies detected a prevalence of 14.9% for P. malariae and 5.3% for Plasmodium ovale. The rate of co-infection of P. malariae or P. ovale with P. falciparum was 8.3% and 2.6%, respectively. Higher rates of sub-microscopic infection were reported for the urban area without seasonal fluctuation. In contrast, non-P. falciparum species infection was more pronounced in the rural area, with the associated risk of the prevalence of sub-microscopic P. malariae infection increasing during the dry season. Conclusion There is a need to include non-P. falciparum species in malaria control programs, surveillance measures and eradication strategies in the Republic of the Congo. Graphical Abstract