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Landslides are a major geohazard that cause thousands of fatalities every year. Despite their importance, identifying unstable slopes and forecasting collapses remains a major challenge. In this study, we use the 7 February 2021 Chamoli rock–ice avalanche as a data-rich example to investigate the potential of remotely sensed datasets for the assessment of slope stability. We investigate imagery over the 3 decades preceding collapse and assess the precursory signs exhibited by this slope prior to the catastrophic collapse. We evaluate monthly slope motion from 2015 to 2021 through feature tracking of high-resolution optical satellite imagery. We then combine these data with a time series of pre- and post-event digital elevation models (DEMs), which we use to evaluate elevation change over the same area. Both datasets show that the 26.9×106 m3 collapse block moved over 10 m horizontally and vertically in the 5 years preceding collapse, with particularly rapid motion occurring in the summers of 2017 and 2018. We propose that the collapse results from a combination of snow loading in a deep headwall crack and permafrost degradation in the heavily jointed bedrock. Despite observing a clear precursory signal, we find that the timing of the Chamoli rock–ice avalanche could likely not have been forecast from satellite data alone. Our results highlight the potential of remotely sensed imagery for assessing landslide hazard in remote areas, but that challenges remain for operational hazard monitoring., Natural Hazards and Earth System Sciences, 22 (10), ISSN:1561-8633, ISSN:1684-9981

Fifty-six cordaitalean trunks with anatomical features are discovered and described from the Moscovian (Pennsylvanian) Benxi Formation in Yangquan City, Shanxi Province, North China. They are allochthonously preserved in fluvial channel deposits and classified into two types based on the anatomy. The first type is characterized by a solid and heterocellular pith, endarch primary xylem and pycnoxylic secondary xylem with araucarian radial tracheidal pits and araucarioid cross-field pitting. The second type contains a septate pith and a pycnoxylic secondary xylem which is comparable to that of the first type. Primary xylem is absent in the second type. The diameter of these trunks ranges from 0.11 m to 0.55 m. The largest tree is estimated to be 29.96 m high using an allometric approach. The trunks represent the oldest and largest trees from the North China Block during the Pennsylvanian due to the absence of Silurian, Devonian, and Mississippian there. The fossil evidence shows that cordaitaleans were large arborescent trees growing on clastic substrates in the Cathaysia during the Pennsylvanian. Their occurrence from the upper Pennsylvanian in North China Block suggests that the previously reported diversity of cordaitaleans, which were estimated based on impressions, is a gross underestimate. The absence of growth rings in the trunks and co-occurrence of arborescent lycopsids in the same interval, together with coal seams and bauxite around the fossil-bearing horizons, indicate that the trees grew under perhumid tropical conditions.

The Alxa Block is a significant tectonic unit in the middle part of the southern Central Asian Orogenic Belt that was affected by multiple Paleozoic and Meso-Cenozoic deformation events. In this st...

Groundwater is an essential source of water due to its substantial use of domestic, irrigation and industrial purpose. The present study was pointed to examine the groundwater quality of groundwater in pre-monsoon and post-monsoon seasons on the year of 2013 at Pennagaram block of Dharmapuri district, Tamilnadu. A few groundwater samples of the study area were analyzed for their physico-chemical parameters (APHA, 1998). The spatial distribution map provides a clear explanation for hydrochemical characteristics of groundwater quality for domestic and irrigational purpose in both the seasons. The results of showed the most of the groundwater samples in the study area showed that the pH is slightly acidic to alkaline in nature. The TDS and EC content of the samples in PRM and POM were measured and found 80% of the samples within the WHO limit (1500 mg/L). The water constituents are highly adjustable with respect to cationic and anionic constituents. However, to summarize the average of cations is Ca2+ ˃ Na+ ˃ Mg2+ ˃ K+ and anions are Cl-> HCO3 > SO4 > NO3 > F. The spatial analysis output indicates that in some stations there is need for some degree of treatment for groundwater in the study area before consumption.

Sea lamprey (Petromyzon marinus) control is achieved in the Laurentian Great Lakes by applying lamprey-specific pesticides (lampricides) to habitats containing larval sea lamprey. Lampricide treatments cost less and are more effective in watersheds where dams block adult sea lamprey migration and limit larval distribution relative to watersheds with no barriers to migration. However, dams impound water and can block movement of valued fishes, outcomes that are untenable for some stakeholders. Here, a seasonal and non-physical barrier of pulsed direct electrical current was tested to block adult sea lamprey while also monitoring the movement and mortality of non-target fish species. The electric barrier was operated in the Black Mallard River, a tributary to northern Lake Huron, March through August 2016–2018. The electric field blocked adult sea lamprey; 1056 adult sea lamprey were captured downstream of the electric field and two were captured upstream of the electric barrier over the three-year study. In 2018, larval sea lamprey abundance upstream of the barrier was about 50% less than historical averages, and genetic analysis found that roughly 98% of larvae upstream of the barrier were spawned in years prior to barrier installation. When the barrier was electrified, non-target fish species were blocked, and a small percentage (

Response of erosive mechanisms to climate change is of mounting concern on Beaufort Sea coasts, which experience some of the highest erosion rates in the Arctic. Collapse of intact permafrost blocks and slumping within sprawling retrogressive thaw complexes are two predominant mechanisms that manifest as cliff retreat in this region. Using aerial imagery and ground survey data from Pullen Island, Northwest Territories., Canada, from 13 time points between 1947 and 2018, we observe increasing mean retreat rates from 0 ± 4.8 m a−1 in 1947 to 12 ± 0.3 m a−1 in 2018. Mean summer air temperature was positively correlated with cliff retreat over each time step via block failure (r2 = 0.08; p = 0.5) and slumping (r2 = 0.41; p = 0.05), as was mean storm duration with cliff retreat via block failure (r2 = 0.84; p = 0.0002) and slumping (r2 = 0.34; p = 0.08). These data indicate that air temperature has a greater impact in slump-dominated areas, whereas storm duration has greater control in areas of block failure. Increasingly, heterogeneous cliff retreat rates are likely resulting from different magnitudes of response to climate trends depending on mechanism, and on geomorphological variations that prescribe occurrences of retrogressive thaw slumps.

In this research, the thermodynamic (energy and exergy) analysis of a single slope solar still using graphite plates and block magnets (GPBMSS) was investigated during summer and winter climatic conditions of Coimbatore city (latitude: 11°01′68′′N and longitude: 76°95′58′′E), in India, 2019. The results observed in GPBMSS were compared with a conventional solar still (CSS) under the same climatic conditions. The outcomes observed that the hourly productivity in GPBMSS was 19.6% and 22.8% higher in summer and winter days, respectively, when compared to CSS. The cumulative productivity in GPBMSS was found to be about 3.93 kg/m2 and 3.56 kg/m2 respectively, for 12 h observations during summer and winter days. Furthermore, the energy and exergy efficiencies of GPBMSS were substantially improved by 20.6% and 18.1% when compared to CSS during summer days. Similarly, the energy and exergy efficiencies of GPBMSS were increased by 18 and 19% compared to CSS in winter days. In addition, the maximum basin exergy destruction was observed in CSS compared to other solar still components. The results observed that the heat storage ability of the graphite plates and water magnetization in GPBMSS greatly decreased the exergy destructions. Finally, the water quality analysis proved that the distillate collected from both GPBMSS and CSS satisfied the requirements recommended by the Bureau of Indian Standards. HIGHLIGHTS Graphite plates and block magnets are attached in a solar still basin (GPBMSS) and improved the productivity by 3.93 kg/m2 and 3.56 kg/m2 respectively, in summer and winter climatic days.; The energy efficiency of GPBMSS was substantially improved by 20.6 and 18%, respectively, compared to CSS during summer and winter days.; The exergy efficiency in GPBMSS was enhanced by 18.1 and 19%, respectively compared to CSS in summer and winter days.

Extreme cold events (ECEs) on the Tibetan Plateau (TP) exert serious impacts on agriculture and animal husbandry and are important drivers of ecological and environmental changes. We investigate the temporal and spatial characteristics of the ECEs on the TP and the possible effects of Arctic sea ice. The daily observed minimum air temperature at 73 meteorological stations on the TP during 1980–2018 and the BCC_AGCM3_MR model are used. Our results show that the main mode of winter ECEs over the TP exhibits the same spatial variation and interannual variability across the whole region and is affected by two wave trains originating from the Arctic. The southern wave train is controlled by the sea ice in the Beaufort Sea. It initiates in the Norwegian Sea, and then passes through the North Atlantic Ocean, the Arabian Sea, and the Bay of Bengal along the subtropical westerly jet stream. It enters the TP from the south and brings warm, humid air from the oceans. By contrast, the northern wave train is controlled by the sea ice in the Laptev Sea. It originates from the Barents and Kara seas, passes through Lake Baikal, and enters the TP from the north, bringing dry and cold air. A decrease in the sea ice in the Beaufort Sea causes positive potential height anomalies in the Arctic. This change enhances the pressure gradient between the Artic and the mid-latitudes, leading to westerly winds in the northern TP, which block the intrusion of cold air into the south. By contrast, a decrease in the sea ice in the Laptev Sea causes negative potential height anomalies in the Artic. This change reduces the pressure gradient between the Artic and the mid-latitudes, leading to easterly winds to the north of the TP, which favors the southward intrusion of cold polar air. A continuous decrease in the amount of sea ice in the Beaufort Sea would reduce the frequency of ECEs over the TP and further aggravate TP warming in winter.

The primary objective of this research was to assess the efficiency of RS and GIS for predicting the flood risk in Raiganj Sub-division, Eastern India using the Frequency ratio, Entropy index, and Weight of evidence-information Value models. Consequently, for spatial analyses fourteen flood conditioning variables are constructed. The research region is experiencing floods consequently in the past with moderate to high intensities. The assessment demonstrates that factors such as elevation, LULC, rainfall, distance from rivers, and drainage density contributed significantly to the occurrence of floods. From the estimation, it is found that about 11.02 per cent (Frequency Ratio result), 13.90 per cent (Entropy’s result), and 11.50 per cent (WofE-IV results) of the total area has very high vulnerability status respectively. Around 33 per cent to 47 per cent of the total area of each block in the subdivision is projected to be in danger of floods. The validation of the results indicates that the success rate of the presently constructed maps was 0.933 for the FR model, 0.917 for the SEI model, and 0.907 for the WofE model indicating that the frequency ratio model for mapping flood risk in the study region is more authentic, reliable, and useful for delineating flood vulnerable areas and potential flood risk sites. The findings of the analysis will help planners to develop flood prevention measures as part of regional flood risk management programs, as well as provide a foundation for future research in the study area.

The present study was conducted to analyze cropping intensity of four blocks (Mogra-Chinsurah, Polba-Dadpur, Singur and Haripal) of the Gangetic alluvial zone of India using multi-dated Sentinel-2 data in 2018–19 cropping year. It was observed that during peak growing stage all crops ascribed higher Normalized Difference Vegetation Index NDVI values (0.4 to 0.73) and NDVI became as low as 0.06 when the fields were vacant. Sentinel-2 data acquired in the peak crop growing period during each cropping season were carefully selected, and NDVI was computed over the whole study area. Rule-based classification was applied for cropping sequence and cropping intensity classification based on the occurrence and non-occurrence of crops using NDVI threshold (0.4). Sentinel-2 images acquired on 22/10/2018, 6/12/2018, 30/1/2019 and 30/4/2019 were used for masking of trees and non-agricultural area. October 22, January 30 and April 30 imageries demonstrated peak crop growing period during kharif, rabi and pre-kharif seasons whereas December 6 image represented occurrence of no or little crop in the study area. Crop acreage was the highest in Polba-Dadpur block during all the three seasons. The crop–fallow—crop sequence occupied the highest areas (43%) followed by crop–crop–crop sequence (39%). 50% and 39% of the total cultivated land was under 200% and 300% cropping intensities. Overall, accuracies of cropping system and cropping intensity classification were 88.54% and 87.85%, respectively. Sentinel-2 data can be successfully used for cropping system analysis which helps in crop planning and management.

Stationary, long-lasting blocked weather patterns can lead to extreme conditions such as anomalously high temperatures or heavy rainfall. The exact locations of such extremes depend on the location of the vortices that form the block. There are two main types of blocking: (i) a high-over-low block with a high located poleward of an isolated low and (ii) an omega block with two lows that lie southeast and southwest of the blocking high in the Northern Hemisphere. In this work, we refine a novel method based on the kinematic vorticity number and the point vortex theory that allows us to distinguish between these two blocking types. Based on the National Centers for Environmental Prediction–Department of Energy (NCEP–DOE) Reanalysis 2 data, we study the trends of the occurrence probability and the onset (formation), decay (offset) and transition probabilities of high-over-low and omega blocking in the 30-year period from 1990 to 2019 in the Northern Hemisphere (90∘ W–90∘ E) and in the Euro-Atlantic sector (40∘ W–30∘ E). First, we use logistic regression to investigate long-term changes in blocking probabilities for full years, seasons and months. While trends are small for annual values, changes in occurrence probability are more visible and also more diverse when broken down to seasonal and monthly resolution, showing a prominent increase in February and March and a decrease in December. A three-state multinomial regression describing the occurrence of omega and high-over-low blocking reveals different trends for both types. Particularly the February and December changes are dominated by the omega blocking type. Additionally, we use Markov models to describe transition probabilities for a two-state (unblocked, blocked) and a three-state (unblocked, omega block, high-over-low block) Markov model. We find the largest changes in transition probabilities in the summer season, where the transition probabilities towards omega blocks significantly increase, while the unblocked state becomes less probable. Prominent in winter are decreasing probabilities for transitions from omega to high-over-low and persistence of the latter. Moreover, we show that omega blocking is more likely to occur and to be more persistent than the high-over-low blocking pattern.

Brick is one of the most important building materials and the demand of it is continuously rising for high increasing of population and the demand for settlement growth. Brick kilns in India are considered by traditional types of manufacturing and established as a significant industry in the unorganized sector. Percentage of female worker is more than male and in most of the cases total family be involved. Indian brick industry is the second biggest in the world after the China which provides livelihood. Among 9 Blocks of Diamond Harbour Sub-Division, Kulpi is the largest block based on number of brick kiln industry. Total brick kiln of the Sub division is 101. But Kulpi has 44 Brick Kilns (equal to 43.46%) covering an area of 60,000 Bigha or 80.3 Sq. Kms acquiring 25.83 % area of the Block itself. Author has attempted to observe the geo-spatial scenario and analysis of brick kiln industry of Kulpi block. Keywords: Locational Status, Brick Kiln Industry, Distribution, Comparison, Analysis, Kulpi Block

Identifying distinct tectonic units is key to understanding the geotectonic framework and distribution law of oil and gas resources. The South China Sea and its adjacent areas have undergone complex tectonic evolution processes, and the division of tectonic units is controversial. Guided by block tectonics theory, this study divide the South China Sea and its adjacent areas into several distinguished tectonic units relying on known boundary markers such as sutures (ophiolite belts), subduction-collision zones, orogenic belts, and deep faults. This work suggests that the study area is occupied by nine stable blocks (West Burma Block, Sibumasu Block, Lanping-Simao Block, Indochina Block, Yangtze Block, Cathaysian Block, Qiongnan Block, Nansha Block, and Northwest Sulu Block), two suture zones (Majiang suture zone and Southeast Yangtze suture zone), two accretionary zones (Sarawak-Sulu accretionary zone and East Sulawesi accretionary zone), one subduction-collision zone (Rakhine-Java-Timor subduction-collision zone), one ramp zone (Philippine islands ramp zone), and six small oceanic marginal sea basins (South China Sea Basin, Sulu Sea Basin, Sulawesi Sea Basin, Banda Sea Basin, Makassar Basin, and Andaman Sea Basin). This division reflects the tectonic activities, crustal structural properties, and evolutionary records of each evaluated tectonic unit. It is of great theoretical and practical importance to understand the tectonic framework to support the exploration of oil and gas resources in the South China Sea and its adjacent areas.

The measurement data obtained at the GPS network in the southwestern part of the Baikal Rift System for the period from 1994 to 2020 were analyzed. The spatial relationship between seismic events and tectonic strain rates was estimated. The field of modern horizontal motions and deformations was calculated for the Tunka, South Baikal, and Khubsugul depressions. The rotation pole of the Siberian block was defined. The general geodynamic setting on the western flank of the Baikal Rift System is characterized by low horizontal velocities in the range of 0.5–1.4 mm yr–1. Based on calculation of the relative deformations, the contrast zones of dilatation with narrow zones with the “non-Baikal” type of directions of deformation processes against the background tectonic extension regimes have been determined for the first time in the Bystraya and Khubsugul tectonic depression. Tectonic stresses are accumulated in these narrow zones and released in earthquakes.

Several fossil woods from Early Cretaceous sediments in Yumen City in northwestern North China Block, China, have been described. They belong to two fossil wood taxa, Piceoxylon yumeniense Zhou, Peng, Deng, Zhang and Yang n. sp. and Protophyllocladoxylon chijinense Zhou, Peng, Deng, Zhang and Yang n. sp. The well-preserved specimens yield secondary xylem with distinct growth rings. Piceoxylon yumeniense exhibits cross-field with taxodioid pits as well as two distinct xylem ray types. The bi- to triseriate rays are characterised by one or two horizontal resin canals with unequal uniseriate ends. Protophyllocladoxylon chijinense Zhou, Peng, Deng, Zhang and Yang n. sp. shows window-like cross-field pits, which are occasionally cupressoid and have uniseriate xylem rays. These fossil wood records improve our understanding of the fossil diversity, floral composition and palaeoclimate of the Xiagou Formation. Palaeoclimatic analysis of the palaeoxylogical assemblage indicates that the northwestern Gansu region predominantly exhibited a warm and wet climate condition, while a brief cooling event may have occurred in the region during the Early Cretaceous.

Atmospheric blocking plays an important role in modulating mid-latitude weather, in particular in the Northern Hemisphere (NH). Trend analysis of atmospheric blocking for both hemispheres by using Sen’s Innovative Trend Analysis (ITA) is performed in this study. The blocking data archived in the University of Missouri covers the period of 1968–2019 for the NH and 1970–2019 for the Southern Hemisphere is used in the study. Block occurrence, duration and blocking intensity (BI) is analysed by classifying the NH (and SH) into three groups according to the preferred blocking locations: Atlantic, Pacific and Continental (Atlantic, Pacific and Indian). In the NH, blocking intensity showed mixed results. It showed a decreasing trend for the entire hemisphere and Atlantic Region, whilst a different trend was shown for different BI clusters. For blocking numbers and duration, the entire hemisphere and regions showed increasing trends. These increasing trend values were also statistically significant. In the SH, blocking intensity showed a decreasing trend for low clusters, whilst medium and high cluster increased for the entire hemisphere. Block duration showed an increasing trend for the entire SH. Block numbers showed increasing trends, except for one point in the low cluster. Blocking characteristics showed different trends for different preferred blocking locations. Increasing trends of blocking numbers for the overall SH and Pacific region are statistically significant at 95% level. Increasing trends of blocking duration for the overall SH, Atlantic and Pacific region are statistically significant at 90%, 95% and 95% level, respectively.

The Kunlun Fault System (KFS), situated on the northern border of the Bayan Har block, central-eastern Tibetan Plateau, is among the most important active regional transform fault systems. The “Maqu seismic gap” (MSG), mainly located in the eastern KFS, is ~ 200-km long. It is composed of the Maqu section, Luocha section, and Hua Lake pull-apart basin. A strong paleoearthquake was identified on the Luocha section, named the Zoige earthquake. It is inferred that the earthquake occurred in 1488 AD. Ruptures caused by this earthquake are distributed intermittently along the Luocha section and form an ~ 50-km-long inverse “L”-shaped deformation zone. The coseismic left-lateral horizontal displacement is 3 ~ 6 m. The macro-epicenter is located west of Benduo village. The estimated magnitude is Mw 7.2 ± 0.2, based on empirical magnitude fault rupture relations. These results indicate that the Luocha section was the causative fault of this earthquake and is dominated by compression-shear stress. The latest earthquakes along the Maqu and Luocha sections occurred 1000 ~ 1500 and ~ 530 years ago, respectively. The next earthquake is more likely to induce segmented ruptures than cascade ruptures. The elapsed time along the Maqu section is close to the earthquake recurrence interval. Therefore, the Maqu section has the risk of seismic activity.

The tectonic evolution of the Sibumasu Block during the Permian remains controversial, and Permian faunas and their paleobiogeographic affinities provide some insight into its paleogeographic and tectonic evolutionary histories. In this paper, a new brachiopod fauna dominated bySpinomartinia prolificaWaterhouse, 1981 is described from the uppermost part of the Taungnyo Group in the Zwekabin Range, eastern Myanmar. This brachiopod fauna includes 23 species and its age is well constrained as late Kungurian by the associated conodonts, i.e.,Vjalovognathus nicolliYuan et al., 2016 andMesogondolella idahoensis(Youngquist, Hawley, and Miller, 1951), contrary to the late Sakmarian age given to the same brachiopod faunas previously reported from southern Thailand and Malaysia. Based on comprehensive comparisons of the Cisuralian brachiopod faunas and other data in different parts of the Sibumasu Block, we consider that they are better subdivided into two independent stratigraphic assemblages, i.e., the lower (earlier)Bandoproductus monticulus-Spirelytha petaliformisAssemblage of a Sakmarian to probably early Artinskian age, and the upper (younger)Spinomartinia prolifica-Retimarginifera alataAssemblage of a late Kungurian age. The former assemblage is a typical cold-water fauna, mainly composed of Gondwanan-type genera, e.g.,BandoproductusJin and Sun, 1981,SpirelythaFredericks, 1924, andSulciplicaWaterhouse, 1968. The latter assemblage is strongly characterized by an admixture of both Cathaysian and Gondwanan elements, as well as some genera restricted to the Cimmerian continents. Notably, the spatial distribution pattern of these two separate brachiopod assemblages varies distinctly. The Sakmarian cold-water brachiopod faunas have been found in association with glacial-marine diamictites throughout the Sibumasu Block including both the Irrawaddy and Sibuma blocks. In contrast, the Kungurian biogeographically mixed brachiopod faunas are only recorded in the Irrawaddy Block, unlike the Sibuma Block that contains a contemporaneous paleotropical Tethyan fusuline fauna. Thus, it appears likely that by the end of Cisuralian (early Permian), the Sibumasu Block comprised the Irrawaddy Block in the south with cool climatic conditions, and the Sibuma Block in the north with a temperate to warm-water environment, separated by the incipient Thai-Myanmar Mesotethys.

The Corsica–Sardinia lithospheric block is traditionally viewed as a region of notoriously low seismicity. Earthquake catalogs report only three moderate earthquakes in the range of magnitudes 5.0–5.1. The scarcity of documented seismicity in the region does not allow for the reliable assessment of the seismic hazard. In this paper, we make an attempt to evaluate the seismic potential of the Corsica–Sardinia region employing the morphostructural zoning (MSZ) that allows for the identification of locations of potential earthquakes. The MSZ delineates the hierarchical system of morphostructural blocks, the network of lineaments bounding the blocks, and the loci of nodes formed around intersections of lineaments. Nodes are treated as earthquake controlling structures. We have used the existing criteria of seismicity defined earlier for seismogenic (M5+) nodes in Iberia and the Western Alps with the goal to identify seismogenic nodes capable of generating earthquakes M5+ in the Corsica–Sardinia block. We test the criteria of seismicity for these regions relying on modern models of the Mediterranean geodynamics that view the eastern margin of Iberia and Provence adjacent to the Western Alps as locations of the Corsica–Sardinia block before drifting. Due to a common tectonic evolution the structure of the Corsica–Sardinia block is roughly similar in the basic features to the structural setting of Iberia and southern France. Out of the 81 nodes delineated by MSZ (deliberately ignoring the available earthquake catalogue) we identify 24 nodes capable of earthquakes M5+ using the criteria of seismicity defined for Iberia. Nodes hosting three documented M5+ earthquakes are assigned to seismogenic ones and most of the nodes accommodating smaller events with magnitudes 4.0–4.9 are also classified as seismogenic by pattern recognition. Applying the criteria of seismicity defined for the Western Alps, we have properly identified only two nodes hosting the documented M5+ earthquakes and missed practically all the nodes with smaller events. The performed analysis reveals that the criteria of seismicity defined for Iberia are more pertinent for the identification of seismogenic nodes in Corsica–Sardinia, because they recognize as seismogenic the nodes marked by documented earthquakes. Our study suggests that the seismic potential of the Corsica–Sardinia block can be specified as low-to-moderate. The defined locations of seismogenic nodes provide key information for knowledgeable long-term seismic hazard assessment of the region.

The displacements of the Earth’s surface before and after the earthquakes that took place near the southern shore of Lake Baikal on September 21, 2020 (Bystrinskoe earthquake with a magnitude of M = 5.5), and August 27, 2008 (Kultukskoye earthquake with a magnitude of M = 6.3), were analyzed using satellite radar interferometry methods. Remote sensing data obtained by the Sentinel-1B (C-band) and the ALOS-1/2 PALSAR-1/2 (L-band) spaceborne synthetic aperture radars were used to study deformation processes. Blocks with different strain rates were found based on the results of analysis of satellite radar interferometric measurements for the period from May 2017 to October 2020 for the Bystrinskoe earthquake and from January 2007 to February 2011 for the Kultukskoe earthquake. The difference in the deformation values before the Bystrinskoe earthquake was 14 mm and that before the Kultukskoe earthquake ranged from 12 to 13 mm.

Urban environments often host a greater abundance and diversity of alien plant species than rural areas. This is frequently linked to higher disturbance and propagule pressure, but could also be related to the additional establishment of species from warmer native ranges in cities, facilitated by the latter's higher air temperatures and drier soils. A hitherto unresolved question is how stressful the urban environments become during climate extremes such as heatwaves and droughts. Do such episodes still favor alien plant species, or set them back? We used in situ measured phenotypic leaf and development trait responses of the six most widespread alien Asteraceae species from various native climates along Belgian urban‐to‐rural gradients, measured during two unusually warm and dry summers. Urbanization was characterized by three factors: the percentage of artificially sealed surfaces (urbanity, measured at three spatial scales from in situ to satellite‐based), the vegetation cover and the sky view factor (SVF, fraction of the hemisphere not blocked by buildings or vegetation). Across species, either from colder or warmer native climates, we found a predominant protective effect of shielded environments that block solar radiation (low SVF) along the entire urban‐to‐rural gradient. Such environments induced lower leaf anthocyanins and flavonols indices, indicating heat stress mitigation. Shielded environments also increased specific leaf area (SLA), a typical shade response. We found that vegetated areas had a secondary importance, increasing the chlorophyll content and decreasing the flavonols index, but these effects were not consistent across species. Finally, urbanity at the organism spatial scale decreased plant height, while broader‐scale urbanity had no significant influence. Our results suggest that sealed surfaces constrain alien Asteraceae during unusually warm and dry summers, while shielded environments protect them, possibly canceling out the lack of light. These findings shed new light on alien plant species success along urban‐to‐rural gradients in a changing climate., Sealed surfaces constrain alien Asteraceae during unusually warm and dry summers, while shielded environments protect them, possibly cancelling out the lack of light. These findings shed new light on alien plant species success along urban‐to‐rural gradients in a changing climate.

Seismic and field observations indicate that the Mw7.4 Maduo earthquake ruptured the Jiangcuo fault, which is a secondary fault ∼85 km south of the northern boundary of the Bayan Hor block in western China. The kinematic characteristics of the Jiangcuo fault can shed lights on the seismogenic mechanism of this earthquake. Slip rate is one of the key parameters to describe the kinematic features of a fault, which can also provide quantitative evidences for regional seismic hazard assessments. However, due to lack of effective observations, the slip rate of the Jiangcuo fault has not been studied quantitatively. In this study, we consider the interaction between the Jiangcuo fault and the eastern Kunlun fault, and estimate the slip rates of the two faults using the interseismic GPS observations across the seismogenic region. The inferred results show that the slip rates of the Jiangcuo fault and the Tuosuo Lake segment of the Kunlun fault are 1.2±0.8 and 5.4±0.3 mm a−1, respectively. Combining the slip rate with the average slip inferred from the coseismic slip model, the earthquake recurrence interval of the Jiangcuo fault is estimated to be 1800 −700 +3700 years (1100–5500 years). Based on the results derived from previous studies, as well as calculations in this study, we infer that the slip rate of the Kunlun fault may decrease gradually from the Tuosuo Lake segment to the eastern tip. The Jiangcuo fault and its adjacent parallel secondary faults may have absorbed the relative motion of blocks together with the Kunlun fault.

Based on the analysis of the distribution of structural-material complexes, facial-genetic types and modeling of the history of immersion of the Lower Cretaceous sediments, the spatial-temporal differentiation of the tectonic regime of the Black Sea megadepression in the Early Cretaceous was established. It is shown that the structural and lithologicalfacial features of the Lower Cretaceous tectonic-sedimentation system were determined by the interaction of tectonic and geological-paleooceanographic factors. Thus, the low sea level and the initial phases of activation of sublatitudinal faults in the Hoterivian-Aptian determined the dominant influence of submeridional tectonic faults on the formation of the corresponding structural-facial block zonation. The increase in the area of the basin, the removal of denudation areas in the Late Albian reduced the intensity of terrigenous discharge, and the prolonged activity of sublatitudinal faults led to the formation of sublatitudinal structural-facial zonation. In the subsequent geological history, the tectonic regime was characterized by a complex mosaic-block character, which influenced the heterogeneity of oil and gas lithofluid systems of Cretaceous deposits.

The geodynamic potential reflects the energy state of the lithospheric blocks, which affects the safety and comfort of human life. The accumulated geodynamic potential acts on the living conditions of humans through its manifestation and development (evolution) in the natural environment with stress relief in the geophysical fields of the Earth. This works evaluates the level of geodynamic potential of the blocks in the northeastern segment of eastern Caucasus located in the arid climate zone in order to make recommendations for appropriate services that prevent harsh geoecological consequences. Paleoseismogeological and structural-tectonic methods with respect to the geodynamic potential of the regional blocks and analysis of the spatiotemporal distribution of seismicity during the instrumental observation period are the main methods of study. Analysis of the study results shows that the region has the Earth’s crust blocks with a critical level of geodynamic potential. A pattern for potential zones of potential earthquake sources and regional blocks with critical geodynamic potential is constructed. The geodynamic potential of the blocks in the northeastern segment of the eastern Caucasus is assessed under the conditions of steppification of terrestrial ecosystems and its geoecologocal significance is shown. The potential zones of expectation of potential sources of strong earthquakes, which may negatively affect ecological safety in the region, are identified. The studies continue the works on the evaluation of the geoecological situation that for under the impact of potential catastrophic geoecological processes of a natural character in a region prone to steppification and aridization.

The mid-latitudes are exposed to outbreaks of Arctic cold air almost every winter. A stretch of below-normal temperatures prevailed over Eastern Europe, the Balkan Peninsula, parts of Mediterranean region and Turkey in the 2018/2019 winter. Extremely low temperatures associated with cold-air advection and considerable snowfalls were observed in parts of Turkey, especially during December and January. This study aims to investigate the association of observed cold anomalies with changes in the upper atmospheric conditions, especially considering polar vortex weakening, from December 2018 to January 2019, when the cold anomalies were more persistent over the country. The findings indicate that the observed cold anomalies during the two-month period were caused by several factors, including northerly and north-westerly Arctic air mass advection from an omega block pattern and polar vortex split, respectively. A persisting ridge across Western Europe caused meridional flow channels from the Arctic region to extend far towards the south. In addition, a deep upper low developed over north-eastern Europe and pushed a strong cold front towards east-central Europe, the Balkan Peninsula and Turkey. The polar vortex split was not as persistent across Eurasia as across North America but still led to cold anomalies, especially in early January 2019. Following the polar vortex split, an Arctic cold advection moved downstream and reinforced the southward displacement of the Siberian high, leading to extended cold anomalies and a stretch of below-normal temperatures over Turkey. An omega blocking pattern across the Western and Northern Europe also enhanced the northerly and north-westerly cold-air advection. In addition, a few intense cut-off lows, which moved across the eastern Mediterranean and Black Seas, intensified the local cold-air advection effects. The negative phase of the arctic oscillation corresponded well with the period of extremely cold temperatures observed over Europe during the 2018/2019 winter. The impact of the North Atlantic Oscillation variability on the cold anomalies portrayed a conflicting result for Turkey when compared to the Northern US, Canada and Northern Europe, where the cold-air outbreaks are usually associated with its negative phase. It is also likely that the decreasing Barents-Kara Sea ice favoured Ural blocking that led below-normal temperatures that impacted Eastern Europe and Turkey.

The rate of global sea level rise is increasing as ice from Greenland and Antarctica melts and warmer seawater expands. By 2050, sea levels could surge by 10 to 25 millimeters per year, according to climate modelers, up from just about 3 millimeters per year now. The rising water could drown some 20% to 90% of the world9s coastal wetlands, destroying habitats that are among the most ecologically valuable on Earth. But coastal scientist Matt Kirwan has argued that such forecasts of wetland loss are needlessly bleak. Studies he and his colleagues have conducted suggest some tidal wetlands can keep pace with sea level rise, by building their soils vertically and migrating inland horizontally as water creeps up coastlines. Some coastal wetlands could even expand, if people don9t block their paths with seawalls or other infrastructure. But many researchers are skeptical of Kirwan9s findings, and have begun to challenge his work.

The Langshan Piedmont fault (LPF) is an active Holocene normal fault that borders Langshan Mountain and the Hetao Graben in the northwest of Ordos Block of China. In this study, paleoseismic trenching was undertaken at three sites and 11 fault outcrops are well exposed. The results show that eight paleoearthquake events occurred on the LPF since 43 ka BP, and six paleoearthquake events are complete since 14 ka BP, the latest event is 2300–2400 a BP; the LPF has the characteristic of quasi-periodic recurrence and the average recurrence interval is 2350 years. Therefore, there is a high probability that the LPF will have another earthquake. The vertical activity rate of the LPF is ~1.12 ​mm/yr since Holocene, and ~0.77 ​mm/yr since 14 ka BP. In this study, it is considered that the LPF is mainly characterized by simultaneous rupture of the whole segment. The vertical displacement of the paleoearthquake events is 0.8–2.5 ​m and the corresponding maximum paleoearthquake magnitude is M 7.4. The seismic hazard of Langshan area should not be ignored. The buildings in Langshan area, especially Wulatehouqi and Qingshan town, should be able to withstand a magnitude 8 earthquake.

Anthropogenic disturbance alters animal movements. Large mammals require vast areas to meet their needs, and they encounter anthropogenic disturbances frequently during daily movements. We assessed the impact of disturbance on the daily movement of two large threatened mammals, and examined the nuances of movement response to type and regeneration of disturbance across seasons. We calculated daily net displacement (Euclidian distance between first and last GPS location) and sinuosity (total path length divided by displacement) of grizzly bears and caribou in west-central Alberta, Canada using GPS locations. We assessed links between daily movement and densities of roads, pipelines, seismic lines, harvest blocks, and wellsites. We also considered the effect of harvest block and seismic line regeneration based on LiDAR-derived vegetation height. During early winter, net displacement of caribou increased in relation to the density of wellsites and harvest blocks. Grizzly bear net displacement increased and sinuosity decreased in relation to the density of non-linear disturbances (harvest blocks, wellsites) during spring. During summer, grizzly bear net displacement increased in relation to secondary road density and decreased in relation to wellsite density. During fall, grizzly bear net displacement decreased in relation to secondary road density and increased in relation to harvest block and pipeline density. Caribou and grizzly bears adjusted their movement in response to disturbances, but each species responded differently and in accordance with its seasonal ecology. Assessing the impacts of disturbance on threatened species across spatiotemporal scales and seasons provides useful insights for multi-species conservation strategies.

The crustal evolution of the Yangtze block and its tectonic affinity to other continents of Rodinia and subsequent Gondwana have not been well constrained. Here, we present new U-Pb ages and Hf isotopes of detrital zircons from the late Neoproterozoic to early Paleozoic sedimentary rocks in the northwestern margin of the Yangtze block to provide critical constraints on their provenance and tectonic settings. The detrital zircons of two late Neoproterozoic samples have a small range of ages (0.87–0.67 Ga) with a dominant age peak at 0.73 Ga, which were likely derived from the Hannan-Micangshan arc in the northwestern margin of the Yangtze block. In addition, the cumulative distribution curves from the difference between the depositional age and the crystalline age (CA–DA) together with the mostly positive εHf(t) values of these zircon crystals (−6.8 to +10.7, ~90% zircon grains with εHf[t] > 0) suggest these samples were deposited in a convergent setting during the late Neoproterozoic. In contrast, the Cambrian–Silurian sediments share a similar detrital zircon age spectrum that is dominated by Grenvillian ages (1.11–0.72 Ga), with minor late Paleoproterozoic (ca. 2.31–1.71 Ga), Mesoarchean to Neoarchean (3.16–2.69 Ga), and latest Archean to early Paleoproterozoic (2.57–2.38 Ga) populations, suggesting a significant change in the sedimentary provenance and tectonic setting from a convergent setting after the breakup of Rodinia to an extensional setting during the assembly of Gondwana. However, the presence of abundant Grenvillian and Neoarchean ages, along with their moderately to highly rounded shapes, indicates a possible sedimentary provenance from exotic continental terrane(s). Considering the potential source areas around the Yangtze block when it was a part of Rodinia or Gondwana, we suggest that the source of these early Paleozoic sediments had typical Gondwana affinities, such as the Himalaya, north India, and Tarim, which is also supported by their stratigraphic similarity, newly published paleomagnetic data, and tectono-thermal events in the northern fragments of Gondwana. This implies that after prolonged subduction in the Neoproterozoic, the northwestern margin of the Yangtze block began to be incorporated into the assembly of Gondwana and then accept sediments from the northern margin of Gondwanaland in a passive continental margin setting.

—Based on the common-mid-point (CMP) seismic data on the 3-DV reference profile, using dynamic conversion of refracted waves into time sections, we constructed velocity sections across four crustal blocks in the boundary region of ​​the Siberian platform and the folded region: the Nizhnealdansakaya (Lower Aldan) depression, Pre-Verkhoyansk foredeep, Sette-Daban block, and West-Verkhoyansk folded area. The four structures contact each other along the fault zones with the velocity model abruptly changing at these boundaries. Within the Lower Aldan depression, the topography of two refractive discontinuities is constructed: the basement boundary and intermediate boundary in the sedimentary cover. In the Pre-Verkhoyansk foredeep, one refractive discontinuity is revealed in the sedimentary cover, whereas the basement boundary in this region is located at greater depths than covered by the observation system. All the discontinuities established in these blocks are lithological. In the uppermost crust of the Sette-Daban block and West Verkhoyansk folded area, gently sloping refractive boundaries with velocity jump and steep velocity gradients directed towards the underlying medium are detected. The Sette-Daban block has especially high seismic velocities. The refractive boundaries in these blocks are not lithological.

It is well documented that sediments record geochemical signatures that reflect the composition and tectonic setting of the rocks providing the detritus for them. This is true of the turbidites in ...

Lyme disease is the most common tick-borne disease in North America. Though human infection is mostly transmitted in a limited geography, the range has expanded in recent years. One notable area of recent expansion is in the mountainous region of southwestern Virginia. The ecological factors that facilitate or constrain the range of human Lyme disease in this region remain uncertain. To evaluate this further, we obtained ecological data, including remotely sensed data on forest structure and vegetation, weather data, and elevation. These data were aggregated within the census block groups of a 9,153 km2 area around the cities of Blacksburg and Roanoke, VA, an area with heterogeneous Lyme disease transmission. In this geographic area, 755 individuals were reported to have Lyme disease in the 10 yr from 2006 to 2015, and these cases were aggregated by block group. A zero-inflated negative binomial model was used to evaluate which environmental variables influenced the abundance of Lyme disease cases. Higher elevation and higher vegetation density had the greatest effect size on the abundance of Lyme disease. Measures of forest edge, forest integrity, temperature, and humidity were not associated with Lyme disease cases. Future southward expansion of Lyme disease into the southeastern states may be most likely in ecologically similar mountainous areas.

Mapping diversity patterns is important to clarify its causes and is essential information for conservation policies. We map the distribution of vascular epiphytes from the Southern block of the Brazilian Atlantic Forest (SBAF) to understand the main factors responsible for the richness and species turnover, as well as to generate information for the conservation of this functional group. We gathered a data set of vascular epiphytes, mapping the richness and weighted endemism using cells of 0.5° × 0.5°, and performed two Generalized Dissimilarity Models (GDM) using a filter of 18 and 54 species in cells of 5 km × 5 km to evaluate the species turnover and correlation with the climatic and topographic factors. We found four sites presenting both a high richness and endemism. A gradient of richness and species turnover between the coastal and inland regions was confirmed, as well as between the lowlands and the mountainous regions. The main predictors obtained from GDM were geographic distance, cloud cover, and temperature seasonality. The topographic heterogeneity and the resulting climate changes are responsible to enhance the richness and species turnover of vascular epiphytes in the SBAF. It is important to conserve the coastal areas and the mountainous gradients due to the high richness and strong species turnover, but also the inland areas since their composition is quite distinct from previous environments.

The 40Ar/39Ar dating of ultrapotassic rocks from Central Chukotka shows that these rocks are Early Cretaceous, and yields a narrow range of age variations (109 to 107 Ma), which correlates fairly well with the range of age variations of granitoids typical of the study area (117–105 Ma). There are thus grounds to suggest that the ultrapotassic magmas and granitoids resulted from the same geological process that can be identified from the material characteristics of the ultrapotassic magmas.In the modern concepts of the regional geological development, the formation of the granitoid and ultrapotassic magmas can be related to the continental lithosphere extension due to the collision of Eurasian plate and the Chukotka – Arctic Alaska continental block.Using modern genetic models based on the interpretations of the material characteristics of ultrapotassic magmas, it is possible to limit the number of genetic hypotheses and to relate the continental lithosphere extension to the processes that took place in the upper mantle of the study area.

Data from a dense seismic network, long-term observations, and modern methods for locating the aftershock hypocenters of the Chuy earthquake in 2003 were used to compile a spatial volumetric seismic portrait of seismically activated faults. The results revealed a cup-shaped structure of the aftershock process with a maximum focal depth of ~20 km at the center of the aftershock region, the presence of uneven changes in density of the aftershock origins along the master strike-slip fault with weakening activity of the main shear zone at the sections of its intersection with faults. The width of the activated zone along the master fault varies from 1–2 km to 10 km, which can be explained by the variability of the zone of influence of the fault with distance. Variability of the slope of the activated master fault, related to the block structure of the epicentral region has been established. The feathering and branching plots on the master fault were identified and studied. Horizontal seismically activated layers extending laterally from the master fault were revealed. Two layers are located at depths of 10–20 km. The first layer is under the Chagan–Uzun block; the second layer is under the northwestern edge of the Kurai depression. The third horizontal layer, at a depth of ~2 km, departs from the master fault to the North Chuy range.

Water is an important natural resource on the surface of earth. Approximately 70% of the water is utilized in the agricultural sectors. Yamuna River having a total drainage area of 366,220 sq Kilometer’s is now highly prone to pollution causing a major threat to the water quality. The present investigation was carried at Sam Higginbottom University of agriculture technology and sciences in the department of Soil Science and Agricultural Chemistry lab. In this study, a total of 24 water samples were collected on 01 November 2020 in Chaka block of Prayagraj district and from each village 3 water samples were collected and analyzed for their primary and secondary irrigation water quality parameters by using standard laboratory techniques. Through this, the results stated that pH is in the range of 6.22-7.34 with mean valve 6.74, EC in the range of 0.61-1.13 dS m-1 with mean valve 0.83, and Irrigation water quality index was in the range of 107.6-177.8, where 100% of the water samples are in poor condition. These analyses concluded that still, improvement has to be done to improve irrigation water quality.

Dumka is the sub-capital of Jharkhand, which is rich in fishery resources. The status of fish diversity was not known from all the water bodies from this area. A study of fish diversity was undertaken in Dumka Block (Latitude 23 ⁰47′ and 24⁰38′ East Longitude 86⁰28′and 87⁰15′). of Jharkhand during 2018 to 2020. Fish sample were collected from different freshwater sources using local contraption and modern nets. 31 species of fishes belonging to 17 families have been described in total. Fishes of cyprinidae family have been found to be dominant followed by Chanidae. Small indigenous fishes have decreased. Some awareness measures need to be taken to conserve the fish species.

An infrequent occurrence of sapphirine from metapelite rocks of the Cardamom hills of South India has been reported. This report of sapphirine may not be the first from the Southern Granulite Terrane (SGT) but is essentially from a new locality. The studied metapelites are silica-undersaturated devoid of garnet and the sapphirine symplectites. The symplectites of orthopyroxene + cordierite, orthopyroxene + K-feldspar + cordierite, orthopyroxene + sapphirine + cordierite ± K-feldspar ± biotite, orthopyroxene + biotite + cordierite + K-feldspar are discernible. The textural patterns show partial to complete pseudomorphism of the initially formed orthopyroxene and sapphirine and their succeeding decomposition to present stage. The relative XMg calculated for the key minerals show the trend as: Crd > Spr > Bt > Opx. The pseudosection modelling and the calculated P-T diagram drawn from the average bulk composition of the studied metapelite connote isothermal decompression with peak pressure and temperature conditions stable at ∼10 Kbar and ∼985 °C respectively. The assemblage reported in this study has an important bearing on the crustal evolution of the high-grade metamorphism exhumed from a deeper level of the crust.

The Xolapa Complex of southern Mexico preserves evidence of its connection with the Chortis Block of Central America. Orthogneisses yielded U-Pb protolith ages from 172 to 169 Ma and paramigmatites...

Groundwater is the major freshwater resource in urban and rural areas of India that provides potable water. The quality evaluation of existing groundwater resources is vital and it's quantity for the optimal utilization and maintenance. The bounding coordinates of the selected study area of Tuticorin industrial area is between 8°38'24" and 8°51'0" latitude and between 77°54'36" and 78°12'36" longitude. Groundwater samples were collected as grid form at 40 locations during the pre- and postmonsoon seasons in the year 2017. Fe, Zn, Co, Pb, Mn, Ni, Cr, and Cu metal concentrations were determined using AAS (Atomic Absorption Spectrophotometer)-Perkin Elmer makes the model AAnalyst 200. Most of the groundwater samples were exceeded by the WHO 2008; USEPA 2009; and BIS 2012 guideline for drinking water standards. Further to assess the groundwater pollution status based on the heavy metal indices such as heavy metal pollution index (HPI), heavy metal evaluation index (HEI), degree of contamination (DOC), hazard quotient (HQ), hazard index (HI). Statistical analyses to found the appropriateness of groundwater for consumption and factors of contamination. The evaluation results indicate that groundwater is highly deteriorated and unsuitable for drinking in premonsoon period. While evaporation of water which increases the heavy metal concentration in premonsoon and dilution factor was affected in postmonsoon season. The increased concentration of heavy metals in groundwater might have been caused by evaporation, anthropogenic activities, and dissolution of rock formations which poses risk to human health. If this kind of growing contamination in the groundwater is unattended, it may lead to various health issues to the people from this region. Therefore, a consistent and sustainable water management should be carried out in this region in order to improve the groundwater quality.

Few studies have determined the relationship between the thermal and methane anomalies associated with earthquakes. In this study, National Center for Environmental Prediction (NCEP) air temperature data and Atmospheric Infrared Sounder (AIRS) total column CH4 data were used to extract the thermal anomalies and methane concentration anomalies before 2008 Wenchuan earthquake. The Granger causality test is then used to support or disprove some conjectures that describe the relation between thermal anomalies and methane anomalies The results show that thermal anomalies appeared from May 5 to 14, 2008, and that methane anomalies appeared from May 12 to 28. Spatially, thermal anomalies occurred to the south of the epicentre in the area with the maximum secular block motion before the earthquake, and the methane anomalies occurred along the Longmenshan Fault as well as the south of the epicentre. The Granger causality results indicate that change in crustal stress caused the thermal anomalies, creating the escaping channels for the underground gases, and then lead to the methane anomalies. In terms of the lag of the methane anomalies, the methane anomalies are unlikely to have been the main cause of the thermal anomalies. However, in the area with large block motion before the earthquake and in the surface rupture area, the methane anomalies may have also influenced the local temperature.

The Qinling orogen, one of the most important orogens in Asia, belongs to the northeastern part of the Tethyan orogen. The architecture and processes of the Qinling orogen remain controversial. In this study, we present 15 new zircon U–Pb ages, 20 whole-rock geochemical and 46 Sm-Nd isotopic analyses, and 30 zircon Lu–Hf isotopic data for early Mesozoic granitoids in this orogen, combining with data from literature, to delineate the crustal architecture and processes of the orogen. A total of 181 zircon U–Pb ages show three phase (252–230, 230–198, and 190–185 Ma) of granitoids. The first-phase granitoids occur mainly in the westernmost segment of the orogen and formed in a subduction setting during the closure of the Mianlue Ocean (a northern branch of the Paleo-Tethyan Ocean). The second- and third-phase granitoids, distributed in the middle to eastern parts of the Qinling orogen, were generated in late syn-collisional and post-collisional tectonic settings, respectively. Whole-rock Nd and zircon Hf isotopic mapping of these granitoids yield six and seven isotopic provinces, respectively. These provinces display that the southern margin of the North China Block and the northern margin of the South China Block are dominated by ancient deep crust, that is, early Paleoproterozoic (2.3–1.8 Ga) and late Paleoproterozoic (∼1.7 Ga) components, respectively. By way of camparison, the North Qinling contains younger Mesoproterozoic [eNd(t) = −10.7 to −0.2; TDM = 1.4–1.0 Ga] basement, evidencing that it is an independent terrane different from the North China Block. The isotopic mapping also reveals a deep-seated NNE–SSW-trending zoned architecture that is approximately perpendicular to the WNW–ENE-trending of the orogen. This provides new evidence for the “Spaghetti Junction model” for the Qinling orogen. The old Nd (2.2–1.0 Ga, mostly 2.0–1.2 Ga) and Hf (2.3–0.8 Ga, mostly 2.0–1.2 Ga) model ages indicate that the continental growth in this orogen occurred mainly during the Paleoproterozoic and Mesoproterozoic, with only minor amounts of juvenile [eNd(t) = ∼0, TDM = ∼0.1 Ga] continental growth along the Shangdan and Mianlue sutures. These characteristics suggest that the Qinling orogen is dominantly formed by the collision of ancient continental blocks, distinct from some typical accretionary orogens, such as the Central Asian Orogenic Belt with voluminous juvenile crust.

With the innovation and development of offshore oil drilling technology, drilling wells in deep waters areas have become an important activity for the development of new hydrocarbon reservoirs in this type of environment. CNOOC (China National Offshore Oil Corporation) won the rights to exploit two unexplored deepwater blocks in the Gulf of Mexico, in a bid realized by the Mexican Government (CNH), in 2016. The challenge to combine the newest technology with the oil industry experienced knowledge to lead the exploration and development of these deep-water blocks in Mexico is around the corner. Therefore, the basic techniques for deep waters wells drilling and the main potential risks are expounded in this paper. A set of deep waters wells drilling processes and methodologies are previously designed, and a specific case is demonstrated next, which provides a referential model for deep waters wells drilling in the Gulf of Mexico.

Reworking or growth of the Hadean (>4.0 Ga) continental crust provides important hints in understanding the early evolution history of Earth. In this study, a comprehensive program of zircon U-Pb dating and Hf isotope analyses, as well as whole-rock major and trace element analyses, has been carried out on the Muzidian granitic gneisses from the northern Dabie orogen. The Muzidian gneisses are tonalite or granodiorite in composition, and have geochemical features resembling those typical of the tonalite-trondhjemite-granodiorite (TTG) suites. Zircon U-Pb dates range from ~2.5–2.4 Ga in the magmatic cores and from ~2.1–2.0 Ga in the metamorphic rims. Both the zircon cores and the rims have highly negative ɛHf(t) values of −25.2 to −19.9 and −31.0 to −28.1, respectively, corresponding to Tcrust of 4.25 Ga to 3.98 Ga, thereby, indicating that the protoliths of the orthogneisses in the northern Dabie orogen were formed by reworking of Hadean continental crust. This provides strong evidence for the presence of Hadean continental crust in the northern Yangtze block. These remnants of Hadean rocks resided in the continental crust of the Yangtze block for more than about 1700 Ma before being reworked. Compared to the ancient crustal components in the Kongling area of the Yangtze block, the Muzidian area along the northern margin of the Yangtze block seems to be more prospective for further occurrences of the Hadean zircon and/or rocks.

Southeast Asia plays a key role in the evolution of the eastern Tethys, which is characterized by accretion and amalgamation of numerous terranes since early Paleozoic. In the present study...

Even though meteorologists have been aware of atmospheric blocking for more than 100 years, it is a phenomenon still not well forecast or completely understood. Also, while there is not one standard accepted definition, there are some commonalities known about the understanding of blocking behavior. Blocking occurs less often than other destructive phenomena, but globally their occurrence has increased since the beginning of the century. The longevity of blocking means it can negatively impact agricultural and economic activity and human comfort by bringing extreme conditions not only to the areas where they occur but also to locations well upstream and downstream. Additionally, while it is known where blocking occurs and their general character has been well described, operational models still struggle to replicate the intensity and duration even though improvement has been noted in the timing and location of onset. Climatologically, models still underestimate their occurrence. In the last 40 years, investigators have used case study analysis and numerical and theoretical models to understand the onset and maintenance of blocking. Comparatively few have examined block decay. This review endeavors to cover the highlights of the history of blocking investigations, especially in the last few decades, in order to provide an understanding for a more general scientific audience.