Evaluation of neotectonic activity using watershed geomorphic analysis: A case study in the west of Dokan Lake, Kurdistan Region, Iraq.

The Iraqi Kurdistan Region's landscapes are the product of a complex merging of the effects of the collision between the Arabian and Eurasian plates and various geomorphic processes. A study of the Khrmallan drainage basin in the west of Dokan Lake, based on a morphotectonic study is a significant contribution to our understanding of the Neotectonic activity in the High Folded Zone. This study investigated an integrated method of detail morphotectonic mapping and geomorphic indices' analysis for determining the signal of Neotectonic activity, using the digital elevation model (DEM) and satellite images. The detailed morphotectonic map, along with extensive field data, revealed considerable variation in the relief and morphology of the study area, and eight morphotectonic zones were recognized. The presence of a high anomalous value in stream length gradient (SL) ranges from 19 to 769, increasing the channel sinuosity index (SI) reaching 1.5, and the tendency of basin shifting through the transverse topographic index (T) ranging from 0.02 to 0.5, conclude that the study area is tectonically active. The strong relationship between the growth of the Khalakan anticline and the activation of faulting is concurrent with the collision of the Arabian and Eurasian plates. A hypothesis of an antecedent can be applied to the Khrmallan valley.

Systematics and biogeography of the Atlantic Forest endemic genus Juliomys (Rodentia: Cricetidae): a test of diversification hypothesis using mitochondrial data

The Atlantic Forest harbors a large species richness and high levels of endemism, but the processes that shaped its biodiversity are poorly studied, especially for mammals. Among them are the endemic mice Juliomys, which comprise forest dwellers distributed in southeastern and southern Brazil, northeastern Argentina, and eastern Paraguay. In this study, we investigate the phylogenetic relationships among species and perform phylogeographic analyses to evaluate the population structure and demographic scenarios through mitochondrial gene cytochrome b sequences. We investigate three hypotheses of diversification (forest refuges, montane isolate, and geomorphological events) to understand the evolution of the Juliomys species. Phylogenetic analyses recovered five clades/lineages, four of which are congruent with species currently recognized. The fifth lineage expands the range of the genus 659 km to the north and may represent a new species. The observed demographic and geographic structure of genetic diversity does not match the forest refuge hypothesis as mechanism to explain the diversification in Juliomys. Our results recovered J. rimofrons and J. ximenezi as sister species, supporting predictions of montane isolate hypothesis. We also detected a shallow genetic structure in J. pictipes and J. ossitenuis. Both phylogeographic breaks were congruent with limits of the São Paulo Basin, an area that has undergone Neogene reactivations of tectonic faults. It is suggested that geomorphological events led to a deformed landscape that influenced the dynamics of sedimentary basins and promoted an incipient population structure in J. pictipes and J. ossitenuis. Our findings demonstrate that the divergences whithin Juliomys species occurred during the Quaternary, too recently to have produced strong geographic structure.

Systematics and biogeography of the atlantic forest endemic genus Juliomys (Rodentia: Cricetidae): A test of diversification hypothesis using mitochondrial data

The Atlantic Forest harbors a large species richness and high levels of endemism, but the processes that shaped its biodiversity are poorly studied, especially for mammals. Among them are the endemic mice Juliomys, which comprise forest dwellers distributed in southeastern and southern Brazil, northeastern Argentina, and eastern Paraguay. In this study, we investigate the phylogenetic relationships among species and perform phylogeographic analyses to evaluate the population structure and demographic scenarios through mitochondrial gene cytochrome b sequences. We investigate three hypotheses of diversification (forest refuges, montane isolate, and geomorphological events) to understand the evolution of the Juliomys species. Phylogenetic analyses recovered five clades/lineages, four of which are congruent with species currently recognized. The fifth lineage expands the range of the genus 659 km to the north and may represent a new species. The observed demographic and geographic structure of genetic diversity does not match the forest refuge hypothesis as mechanism to explain the diversification in Juliomys. Our results recovered J. rimofrons and J. ximenezi as sister species, supporting predictions of montane isolate hypothesis. We also detected a shallow genetic structure in J. pictipes and J. ossitenuis. Both phylogeographic breaks were congruent with limits of the São Paulo Basin, an area that has undergone Neogene reactivations of tectonic faults. It is suggested that geomorphological events led to a deformed landscape that influenced the dynamics of sedimentary basins and promoted an incipient population structure in J. pictipes and J. ossitenuis. Our findings demonstrate that the divergences whithin Juliomys species occurred during the Quaternary, too recently to have produced strong geographic structure.

Neotectonics and pastoralism: How they impact flood regimes in Madagascar's highlands.

Sustainably maintaining the densely populated upland plains of Madagascar as operationally safe spaces for the food security of the nation and the urban growth of its capital city, Antananarivo, hinges critically on avoiding crop and infrastructure destruction by their through-flowing rivers. The flood regime, however, is also a function of two 'slow' variables hitherto undocumented: tectonic subsidence regime, and floodplain sedimentation rate. From a radiocarbon-dated chronostratigraphy and environmental history of the sediment sequences in three of Madagascar's semi-enclosed upland basins (Antananarivo, Ambohibary, and Alaotra), we quantify and compare how the precarious equilibrium between the two variables entails differentials in accommodation space for sediment and floodwater. Results show that all these plains have been wetlands for at least 40,000 years, but that the Antananarivo Basin is the most vulnerable because the imbalance between sedimentation and subsidence is the largest. Although the tectonic regime and the endemic forms of gully erosion that occur in the catchments are beyond human control, we advocate that flood mitigation strategies should focus on the natural grassland savanna, which makes up most of the contributing areas to surface runoff in the watersheds. Pastoralists are persistently left out of rural development programmes, yet the rangelands could benefit from the introduction of multi-purpose grasses and legumes known to withstand high stocking rates on poor soils while combining the benefits of nutritiousness, fire and drought resistance, with good runoff-arrest and topsoil-retainment abilities. Future-proofing Madagascar's upland grainbaskets and population centres thus calls for joined-up action on the sediment cascade, focusing on soil and water sequestration through integrated watershed management rather than on hard-defence engineering against overflowing rivers on the plains, which has been the costly but ineffectual approach since the 17th century.

Drivers of water pollution and evaluating its ecological stress with special reference to macrovertebrates (fish community structure): a case of Churni River, India.

The focus of this study is to measure ecological stress of Churni River based on the estimates of dissolved oxygen (DO), pH, biological oxygen demand (BOD), chemical oxygen demand (COD), nutrients imbalances of dissolved inorganic nitrogen or DIN (NO3- N and NO2- N) and dissolved inorganic phosphate or DIP (PO43-). The present water quality measured in terms of overall index of pollution (OIP), eutrophication index (EI), organic pollution (OPI) and water pollution indexes for ecological status (WPI) portrays that the river is polluted having a high concentration of BOD, COD, nutrients (DIP and DIN) and a very low concentration of DO. Fish community structure taken as most sensitive indicator of ecological stress of water pollution depicts that out of 44 species, 28 fish species (63.63%) comprising 20.0% planktivore (PL), 9.09% benthic feeder (BE), 18.18% omnivorous (OM) and 15.90% carnivorous (CA) at Majhdia and 21 fish species (47.72%) comprising 18.18% PL, 4.59% BE, 13.63% OM and 11.36% CA at Ranaghat have been disappeared. The present investigation has found that anthropogenic interventions like disposal of industrial effluents and agricultural run-off from on-bed and off bed land use are the main drivers of the pollution. Furthermore, natural forcing in the form of neotectonic movements and monsoon regimes has intensified the problem.

Radon measurements in an area of tectonic zone: A case study in Central Slovakia.

General overviews of the spatial distribution of radon and other natural radionuclides in the geological basement as commonly presented on regional or country maps tend to offer a low density of information, insufficient for gaining relevant knowledge of the environmental impact, especially in the areas of tectonic zones often assumed to be radon prone and therefore dangerous for the human population. An additional survey, employing radon measurements in soil and indoor air, was carried out seeking to provide a more detailed characterization of the expressive fault zone of the Malá Magura in the Horná Nitra region of Central Slovakia. Eventually, the results of soil 222Rn volume activity measurements along two short profiles crossing the assumed fault line did not reveal any indication of active nature of local tectonics, but merely pointed to an existence of a zone of contact between different types of rocks. The results of indoor radon measurements in dwellings of two villages lying on the studied fault showed values that were lower than those commonly observed on the Slovak territory, ruling out any negative health impact on population. Nevertheless, in order to add new findings to an already well established study of geological structure of the region, the indoor radon data collected through a previous survey require a further analysis.

Analysis of tectonic-controlled fluvial morphology and sedimentary processes of the western Amazon Basin: an approach using satellite images and digital elevation model

An investigation of the tectonic controls of the fluvial morphology and sedimentary processes of an area located southwest of Manaus in the Amazon Basin was conducted using orbital remote sensing data. In this region, low topographic gradients represent a major obstacle for morphotectonic analysis using conventional methods. The use of remote sensing data can contribute significantly to overcome this limitation. In this instance, remote sensing data comprised digital elevation model (DEM) acquired by the Shuttle Radar Topographic Mission (SRTM) and Landsat Thematic Mapper images. Advanced image processing techniques were employed for enhancing the topographic textures and providing a three-dimensional visualization, hence allowing interpretation of the morphotectonic elements. This led to the recognition of main tectonic compartments and several morphostructural features and landforms related to the neotectonic evolution of this portion of the Amazon Basin. Features such as fault scarps, anomalous drainage patterns, aligned ridges, spurs and valleys, are expressed in the enhanced images as conspicuous lineaments along NE-SW, NW-SE, E-W and N-S directions. These features are associated to the geometry of alternated horst and graben structures, the latter filled by recent sedimentary units. Morphotectonic interpretation using this approach has proven to be efficient and permitted to recognize new tectonic features that were named Asymmetric Ariaú Graben, Rombohedral Manacapuru Basin and Castanho-Mamori Graben.

Uma investigação do controle tectônico da morfologia fluvial e dos processos sedimentares de uma área localizada a sudoeste da cidade de Manaus, na Bacia do Amazonas, foi conduzida a partir do uso de dados de sensores remotos orbitais. Nessa região, o baixo gradiente topográfico representa o principal obstáculo para a análise morfotectônica usando métodos convencionais. O uso de dados de sensores remotos pode contribuir significativamente para superar essa limitação. Desse modo, dados de sensoriamento remoto, compreendendo modelo digital de elevação (DEM) obtido pelo Shuttle Radar Topographic Mission (SRTM) e imagens Landsat TM, foram utilizados para essa investigação. Técnicas avançadas de processamento de imagem foram empregadas para realce de imagens topográficas e sua elaboração tridimensional, permitindo desse modo, a interpretação dos elementos morfotectônicos. Isso permitiu o reconhecimento de principais compartimentos tectônicos, diversas feições morfoestruturais e formas de relevo relacionadas à evolução neotectônica dessa porção da Bacia do Amazonas. Feições como escarpas de falha, padrão anômalo na drenagem, alinhamentos de relevo, vales e divisores d'água foram realçados nas imagens como notáveis lineamentos ao longo das direções NE-SW, NW-SE, E-W e N-S. Essas feições foram associadas à geometria de estruturas do tipo horste e gráben alternados, este último preenchido por unidades sedimentares recentes. A interpretação morfotectônica usando essa técnica mostrou-se eficiente e permitiu o reconhecimento de novas feições tectônicas as quais foram denominadas de Gráben Assimétrico Ariaú, Bacia Romboédrica de Manacapuru e Gráben Castanho-Mamori.