Northwest Portion Research Articles

Geomagnetically induced currents (GICs) during strong geomagnetic activity (storms, substorms, and magnetic pulsations) on 23–24 April 2023

We analyzed intense geomagnetically induced currents (GICs) recorded during a complex space weather event observed on 23–24 April 2023. Two geomagnetic storms characterized by SYM/H intensities of −179 nT and −233 nT were caused by southward interplanetary magnetic field (IMF) Bz component of −25 nT in the sheath fields, and −33 nT in the magnetic cloud (MC) fields, respectively. GIC observations were divided into two local time sectors: nighttime (1700–2400 UT on 23 April) GICs observed during the interplanetary sheath magnetic storm, and morning sector (0200–0700 UT on 24 April) GICs observed during the MC magnetic storm. By using the direct measurements of GICs on several substations of Karelian-Kola power line (located in the north-west portion of Russia) and gas pipeline station near Mäntsälä (south of Finland), we managed to trace the meridional profile of GIC increases at different latitudes. It was shown that the night sector GIC intensifications (∼18–42 A) occurred in accordance with poleward expansion of the westward electrojet during a substorm. On the other hand, the intense morning sector GICs (∼12–46 A) were caused by Ps 6 magnetic pulsations. In addition, a strong local morning GIC (∼44 A) was associated with a local substorm-like disturbance caused by a high-density solar wind structure, possibly a coronal loop portion of an interplanetary coronal mass ejection.

Distinct Element Method Analyses for Damage Assessment: The Northern Spur of Valverde Bulwark in the Venetian Fortress of Bergamo

ABSTRACT The 16th century Venetian Fortress, with more than 70,000 m2 of masonry wall facing, characterises the city landscape of Bergamo. Almost intact and well preserved, the defensive system was inscribed on the UNESCO World Heritage List in 2017. Today, the first causes of its deterioration are the vegetation growth and the lack of maintenance, which have led to instabilities and local failures, particularly in the northwest portion. Thus, in 2019 and 2020, survey campaigns were carried out to assess the safety of one of the most damaged sections, the Valverde bulwark. The survey combines on-site observations, laboratory tests, and photogrammetric and laser scanner surveys to describe the bulwark. Numerical simulations have been performed using a distinct element approach, i.e. assimilating the masonry to a system of discrete bodies consisting of blocks (usually rigid) interacting on their interfaces. A routine dedicated to defining a real-like geometrical model has been developed. The numerical analyses were run to assess the conditions of the Valverde bulwark under self-weight and earth pressure and considering seismic load. Through the detailed survey and its automatic digitisation, it is possible to fully recognise and analyse the state of health of these historic structures and their mechanical behaviour.

TREE PLANTING PRIORITIZATION IN NATIONAL CAPITAL REGION, PHILIPPINES USING REMOTE SENSING, ANALYTIC HIERARCHY PROCESS AND GIS

Abstract. The need for trees in cities is rapidly increasing because of global warming, rapid population growth, and urbanization. To maximize the benefits of trees, areas of greatest need should be identified and prioritized. In this study, a geospatial framework for tree planting prioritization is developed for NCR using remotely sensed datasets, AHP, and GIS. A Planting Priority Index (PPI) for NCR is derived based on five criteria with corresponding weights calculated based on ratings from 18 experts – air quality (25.2%), tree cover (23.8%), land cover (17.8%), population (17.4%), and land surface temperature (15.8%). The AHP resulted in a consistency ratio (CR) value of 1.7% and a consensus value of 53.2%. PPI values were calculated and statistically significant prioritization clusters and outliers were identified using Anselin Local Moran’s I statistics. The resulting PPI and cluster maps showed that the high-priority areas for tree planting clustered near the region’s center and northwest portion covering the cities of Malabon, South Caloocan, Navotas, Quezon City, Marikina, San Juan, and Mandaluyong, while the low priority areas were found mostly along the region’s outskirts at cities of Pasay, Las Piñas, Muntinlupa, Taguig, Valenzuela, and North Caloocan. The generated maps showing PPI values across the region may aid local government agencies and environmental organizations in evaluating and recalibrating their local greening programs. The workflow presented in this study can also be adopted in other regions with localized variables and site-specific goals relevant to tree planting and greening programs.

Climatic damage cause variations of agricultural insurance loss for the Pacific Northwest region of the United States.

Abstract Agricultural crop insurance is an important component for mitigating farm risk, particularly given the potential for unexpected climatic events. Using a 2.8 million nationwide insurance claim dataset from the United States Department of Agriculture (USDA), this research study examines spatiotemporal variations of over 31,000 agricultural insurance loss claims across the 24-county region of the inland Pacific Northwest (iPNW) portion of the United States, from 2001 to 2022. Wheat is the dominant insurance loss crop for the region, accounting for over 2.8 billion dollars in indemnities, with over 1.5 billion dollars resulting in claims due to drought (across the 22 year time period). While fruit production generates considerably lesser insurance losses (400 million dollars) as a primary result of freeze, frost and hail, overall revenue ranks number one for the region, with 2 billion dollars in sales, across the same time range. Principal components analysis of crop insurance claims showed distinct spatial and temporal differentiation in wheat and apples insurance losses using the range of damage causes as factor loadings. The first two factor loadings for wheat accounts for approximately 50 percent of total variance for the region, while a separate analysis of apples accounts for over 60 percent of total variance. These distinct orthogonal differences in losses by year and commodity in relationship to damage causes suggest that insurance loss analysis may serve as an effective barometer in gauging climatic influences.

Use of Forensic Methods In Disclosure of Fire Insurance Claims

When an insurance claim occurs, there is often a difference of opinion between the insurer and the insured in interpreting the contents of the policy. In order to resolve claim disputes, according to the clauses in the policy, an opinion from an independent third party is needed. The purpose of third party involvement is to provide an opinion from another point of view. In this research, it is described how third parties are involved in resolving an insurance claim. Starting from the incident report, it was reported that a fire had occurred at latitude coordinates 7°25'26"S and longitude 112°43'33"E. Appointed investigators visit places affected by the fire to carry out inspections at the scene and investigate the origin of the fire and look for possible causes of the fire. Using forensic methods that include on-site investigation, damage analysis, witness statements, interpretation, and deductive reasoning processes, data collected in the field is then analyzed to be tested against a number of proposed hypotheses. Debris and electrical cable samples were collected for further analysis. Based on physical evidence collected during the investigation, it was discovered that the fire started in the northwest portion of the building. The results of the findings were then traced by tracing the parts of the building that were damaged, and investigators found an electrical short circuit due to a failure in the lights. These findings are then analyzed by the insurance claims team to determine the amount of the claim that must be paid by the insurer. There were no suspicious elements or circumstances surrounding the fire and other possible causes of the fire have been considered and ruled out.

Site response analysis beneath the Kashmir basin (NW Himalaya) using ambient noise

Deep sedimentary valleys entrap and amplify seismic waves, which is further responsible for site-specific amplification over the allied region. Kashmir valley is a deep and active sedimentary basin in the northwest portion of the Himalayan lap. To characterize the site response for the intermountain Kashmir valley for the first time, we acquire single station microtremor measurements using Lennartz (three components/5s seismometer) at 141 sites with a grid of (5 km × 5 km) and two-dimensional (2D) array measurements using seven units of recording station of different geometry pattern at 38 sites across different lithological setup within the basin. We present here (1) a first-order predominant fundamental frequency (0.21–10.19 Hz) and subsequent sedimentary thickness maps for the entire valley, reflecting deep deposition with spatial heterogeneity in the area using the horizontal-to-vertical spectral ratio (HVSR) technique; (2) spatial classification of generated HVSR curves linking subsurface geomorphology and post strong ground-motion scenario in the valley; (3) extraction of the best dispersion characteristics of Rayleigh waves (fundamental mode) from all recorded vertical signals at each array site using frequency–wavenumber (F-K) method with an emphasis on signal synchronicity; and (4) retrieval of one-dimensional (1D) shear wave velocity ( VS) profiles across the valley from the inversion of dispersion curves using the neighborhood algorithm. Distinct model parameterizations were tested for the inversion to achieve the optimal inversion misfit. The collocated 1D VS profiles are consistent with newly drilled borehole logs information. Besides, the presented first-ever ambient noise survey–based site response study meets the objectives of site-specific seismic hazard and risk analysis of the Kashmir valley at the regional scale.

Bringing to Light the Potential of Angular Nighttime Composites for Monitoring Human Activities in the Brazilian Legal Amazon

The Brazilian Legal Amazon (BLA) is the largest administrative unit in Brazil. The region has undergone a series of territorial policies that have led to specific conditions of occupation of the land and particular urban environments. This plurality expresses specific physical relations with the environment and infrastructure, which require innovative methods for detecting and profiling human settlements in this region. The aim of this work is to demonstrate how angular composites of nighttime lights can be associated with specific profiles of urban infrastructure, sociodemographic parameters, and mining sites present in the BLA. We make use of sets of yearly VNP46A4 angular composites specifically associated with the narrowest ranges of observations across the year, i.e., observations right below the sensor’s pathway (near-nadir range) and observations in between the oblique range (off-nadir), to identify urban typologies that expose the presence of structures such as vertical buildings, industrial sites, and areas with different income levels. Through a non-parametric evaluation of the simple difference in radiance values ranging from 2012 to 2021, followed by an ordinary least squares regression (OLS), we find that off-nadir values are persistently higher than near-nadir values except in areas where obstructing structures and particular anisotropic characteristics are present, generally changing trends of the so-called angular effect. We advocate that relational metrics can be extracted from the angular annual composites to provide additional information on the current urban structural state. By calculating the simple difference (DIF), the relative difference (REL), and the residual values of the linear regression formula estimated for the off-nadir and near-nadir composites (RES), it is possible to differentiate urban environments by their physical aspects, such as high-mid income areas, low-income settlements with different levels of density, industrial sites, and verticalized areas. Moreover, pixels that were exclusively found in one of the angular composites could be spatially associated with phenomena such as the overglow effect for the exclusive off-nadir samples and with the wetlands of the northwest portion of the Amazon Forest for the near-nadir samples. This work deepens our current understanding of how to optimize the use of the VNP46A4 angular series for monitoring human activities in the Amazon biome and provides further directions on research possibilities concerning nighttime light angular composites.

Molecular epidemiology of antibiotic-resistant Escherichia coli among clinical samples isolated in Azerbaijan, Iran.

The immediate emergence of resistant bacteria poses an increasingly growing problem to human society and the increasing prevalence of antibiotic resistance in Escherichia coli strains is one of the most important health problems. This study aimed to review the molecular epidemiology of drug resistance among clinical isolates of E. coli in north-west portion of Iran Azerbaijan. A complete of 219 clinical isolates of E. coli had been collected from the various clinical samples. The disk diffusion and agar dilution assays were used to determine antimicrobial susceptibility. The presence of antibiotics resistance genes was carried out by the PCR method. The highest susceptibility was shown to imipenem (3%) and fosfomycin (3%), and the most antibiotic resistance was presented to ampicillin (99%). The highest frequent ESBL gene among isolates was bla CTXM-15 in 70% followed by blaCMY-2 in 67%, and blaTEM-1 in 46%. The most common fluoroquinolone (FQ) resistance genes were oqxB (34%), followed by oqxA (25%), and qnrB (18%). The frequency of tetracycline resistance genes (tetA, tetB, tetC, and tetD) were detected in 24.8%, 31.6%, 1.8%, and 4.2%, respectively. The highest frequent genes to fosfomycin were fosA 10%, fosA3 30%, fosC 40%, and fosX 20%. The dominant founded aminoglycosides resistant genes were armA (12.96%) and npmA (4.93%). The prevalence of antibiotics resistance in the tested E. coli isolates was high in Azerbaijan, Iran and these findings showed that E. coli is one of the major drug-resistant pathogens.

Formation Waters Delineate Diverse Hydrogeologic Conditions at a Plate Scale: Eastern Flank of the Juan de Fuca Ridge

AbstractThe chemical composition of formation waters within the upper basaltic crust were calculated or measured at 24 sites on the northwest portion of the Juan de Fuca (JDF) Plate using data from sediment pore waters, scientific boreholes, and seafloor springs. Formation waters differ in composition across this ridge‐flank region because of variations in water‐rock reactions and residence times, exchange rates with overlying sediment pore waters, and microbial processes along flow paths. We interpret spatial variations in the solute composition of formation waters to resolve areas that are geochemically distinct or similar, lateral trends that result from water transport, areas where water‐rock reactions in the deeper crust are apparent, and sites of seawater recharge and formation water discharge. We provide evidence for large‐scale lateral flow associated with two (mostly) buried basement ridges on ∼1.4 and ∼3.5 Ma seafloor, which are subparallel to the JDF spreading axis to the west. Between these two ridges, where the seafloor and the sediment‐basement interface are relatively flat, formation waters have undergone extensive exchange with overlying sediment pore waters, consistent with a long residence time. Basaltic outcrops provide sites of seawater recharge and hydrothermal discharge, sometimes through the same feature, highlighting the heterogeneous nature of hydrogeologic conditions and processes. This work provides a blueprint for future plate‐scale studies to assess, for example, geologic controls of crustal age, spreading rate, and sedimentation on subsurface hydrologic patterns.

Quantifying Heavy Precipitation throughout the Entire Tropical Cyclone Life Cycle

Abstract Tropical cyclones (TCs) and their associated precipitation can have devastating impacts on the areas affected, with outcomes ranging from mudslides to inland flash flooding. Previous studies have used a fixed radius around the TC to isolate storm-related precipitation. One previous study instead used a dynamic radius of 8 m s−1 winds, but the wind field of the TC can deteriorate or shift quickly after landfall or the onset of extratropical transition (ET). This study uses a dynamical radius derived from the 500-hPa geopotential height in and around the TC to define TC- and post-tropical cyclone (PTC)-related heavy precipitation, allowing for the analysis of precipitation with tropical origins after the official demise of the original TC. Climatologies are constructed, indicating a maximum in TC- and PTC-related heavy precipitation in the west North Pacific and a secondary maximum in the east North Pacific. PTC-related heavy precipitation accounts for as much as 40% of the annual heavy precipitation in the northwest portion of the west North Pacific basin and 3.13% of heavy precipitation globally. We observe that the major hurricane stage contributes on average 2.6% of the global TC- and PTC-related precipitation, while the less intense but more common tropical storm stages of the TC life cycle contribute 85.7% of this observed precipitation. This analysis framework can be further extended to assess model biases and climate projections of TC and PTC precipitation.

Role of landscape features in resource selection by female Greater Prairie-chickens within a constrained environment

Greater Prairie-chickens ( Tympanuchus cupido ) historically occupied 20 states within the contiguous United States; however, due to habitat degradation and loss, they are currently found in 11 states, only four of which have a stable population. Kansas supports a relatively large abundance of Greater Prairie-chickens, where the Flint Hills ecoregion historically supported the largest population density of all ecoregions. In the past decade, the Flint Hills population has declined by 75 % to an estimated 8,334 individuals in 2021 from 34,180 individuals in 2015 due to landscape changes and intensification of grassland management practices. The Fort Riley Military Reservation in the northwest portion of the Flint Hills ecoregion is one of a few areas within the ecoregion that does not implement grazing or vast annual burning. The Greater Prairie-chicken population within Fort Riley has remained relatively stable over the past 25 years despite being constrained by surrounding landscape features and development. We analyzed multiple scales of resource selection by 46 female Greater Prairie-chickens during March-April 2019–2021 on Fort Riley to investigate why this population is doing relatively well compared to populations in surrounding areas. We tested landscape feature, vegetation, and burn mosaic variables to evaluate which variables had the greatest influence on resource selection. Landscape features had the greatest influence on resource selection. Females avoided trees within Fort Riley for both breeding season use and nest-site selection at a greater margin than any other study in Kansas. Additionally, fourth-order selection was not evident within this study system, contrary to studies within surrounding areas. Our findings join a growing body of literature that suggests containment of woody encroachment as a high priority for managers to maintain or expand prairie grouse habitat in many different environments. This containment is especially critical on Fort Riley because of its constrained environment, and further woody encroachment could lead to loss of habitat that is inescapable by the Greater Prairie-chicken population on Fort Riley. Spatially-explicit evaluations of habitat availability are increasingly important as more areas within the Greater Prairie-chicken range become constrained by urbanization, agricultural expansion, and intensive management practices.

The molecular characterization of colistin-resistant isolates of Acinetobacter baumannii from patients at intensive care units.

The objective of this study was to determine molecular characterization and genetic diversity of colistin-resistant A. baumannii clinical isolates in Intensive Care Unit hospitalized patients. A total of 127 A. baumannii clinical isolates were evaluated for antimicrobial susceptibility. PCR reaction and sequencing were performed for the detection of mutations in pmrAB and lpx ACD genes. Based on antimicrobial susceptibility testing, 40.94% and 33.85% of the isolates were MDR and XDR respectively whereas 3.93% of them were found to be PDR. Results of agar dilution MIC and E-test indicated that 76% of the isolates were sensitive to colistin. All of the isolates were positive for bla OXA-51 and 50% of them were positive for both bla OXA-23 -like and bla OXA-143 -like genes while only 25% of the isolates were positive for bla OXA-72 . None of them were positive for the bla OXA-58 -like gene. There is no mutation in pmrA. The V162A substitution for pmrB gene was repeated in two isolates, and E394D and Y292H substitutions in lpxA were observed in two isolates; also, C120R and F165L substitutions in lpxC gene was repeated in two isolates. Analysis of phylogenetic tree based on alterations in lpxACD and pmrB genes indicated the appearance of new isolates compared to the reference strain ATCC17978 A. baumannii isolates. The present study indicated the prevalence of MDR and XDR A. baumannii isolates and the emergence of PDR isolates in the northwest portion of Iran. The appearance of colistin-resistant isolates with new mutations in pmrB, lpxACD genes indicates new resistance mechanisms.

Student Perceptions of Course Configuration: Hybrid and Face-to-Face Models

Hybrid or blended learning has gained enormous popularity in higher education because of its demonstrated ability to increase student learning, reduce undergraduate attrition rates, and maintain costs in an era of relentlessly increasing tuition. This study reviews the literature on hybrid or blended learning, enumerating both the benefits and liabilities of this type of instruction and the controversies surrounding it. The researchers then describe the two forms of a mixed-methodology survey instrument used to determine the satisfaction of primarily undergraduate students who are enrolled in separate sections of an introduction to education course, one taught in a traditional face-to-face mode and one in a blended configuration during two academic terms at a public regional comprehensive university in the Northwest portion of the United States. They then analyze the findings of the qualitative and quantitative data with recommendations for further research.

Gravity surveys and 3D integrated model with magnetic and geological data of the granite-greenstone terrane in Pitangui Synclinorium, NW of the Quadrilátero Ferrífero (MG, Brazil)

The Pitangui Greenstone Belt (PGB) is a Meso to Neoarchean metavolcano-sedimentary sequence, inserted in the Pitangui Synclinorium, located in the northwest portion of the Archean-Paleoproterozoic metallogenic province of the Quadrilátero Ferrífero, southern of the São Francisco craton (Brazil). The PGB holds important gold mines like the Turmalina Complex and recently discovered deposits, as São Sebastião. The PGB is mapped in detail scale, but there is still little information about its subsurface configuration. This paper presents gravity surveys, constrained by geological, structural, boreholes, aeromagnetic and seismic data, aiming to provide a better understanding of the 3D geometry of this granite-greenstone terrane. The treatment of the available data resulted in Bouguer anomaly maps, 2D gravity modelling and a 3D geological-geophysical integrated model. The gravity Bouguer anomalies of the region present high amplitudes associated with the PGB, alternating with low zones related to the surrounding granite-gneiss rocks. The profiles and the model suggest that the maximum depth of the greenstone belt is approximately 5 km in its central portion, being strangled by granitic intrusions in its southernmost region. The PGB is about 100 km long, but most of it is covered by Neoproterozoic sediments of the Bambuí Group and Quaternary deposits, which significantly increase its metallogenic potential, especially in regions with few mineral exploration works. The 3D model contributes to the understanding of the tectonic framework and evolution of the PGB, showing the spatial relation with the surrounding granite-gneiss basement and intrusions, and younger sedimentary covers, providing valuable insights about their depth, vertical and lateral geometry. Additionally, this new data can become a valuable tool for developing strategies to select deep mineral targets, expanding the exploratory potential for this mineral province.

Characterization of the Gamma-ray Emission from the Kepler Supernova Remnant with Fermi-LAT

The Kepler supernova remnant (SNR) had been the only historic SNR that lacked a detection at GeV and TeV energies, which probe particle acceleration. A recent analysis of Fermi-LAT data reported a likely GeV γ-ray candidate in the direction of the SNR. Using approximately the same data set but with an optimized analysis configuration, we confirm the γ-ray candidate to a solid >6σ detection and report a spectral index of 2.14 ± 0.12stat ± 0.15syst for an energy flux above 100 MeV of (3.1 ± 0.6stat ± 0.3syst) × 10−12 erg cm−2 s−1. The γ-ray excess is not significantly extended and is fully compatible with the radio, infrared, and X-ray spatial distribution of the SNR. We successfully characterized this multiwavelength emission with a model in which accelerated particles interact with the dense circumstellar material in the northwest portion of the SNR and radiate GeV γ rays through π° decay. The X-ray synchrotron and inverse-Compton emission mostly stem from the fast shocks in the southern regions with a magnetic field B ~ 100 μG or higher. Depending on the exact magnetic field amplitude, the TeV γ-ray emission could arise from either the south region (inverse-Compton dominated) or the interaction region (π° decay dominated).

Trends in monthly and annual streamflow related to rainfall and land use at the Atlantic rainforest biome

Understanding trends in rainfall and streamflow over time are essential for water resources planning and management. This study analyzed trends in the streamflow of the Itapemirim river basin (IRB) in Southeastern Brazil and to relate these trends with changes that occurred in rainfall and land use (from 1969 to 2018). Accumulated rainfall decreased in the dry period. In October (considered the beginning of the hydrological year), rainfall amounts decreased in all sub-basins and suggested a shift of the beginning of the rainy period to November. Increasing rainfall was only observed for December and only in the west and northwest portion of the IRB. Average monthly streamflow showed a downward trend and followed downward trends in rainfall depth from the same month or the immediately previous one. Decreases of 25–40% in minimum streamflow occurred in most sub-basins and dated mainly from the 1990's. There was an increasing trend in maximum streamflow of 28–48% in the Braço Norte Direito River and in the Itapemirim River.

Exploratory plays of the Foz do Amazonas Basin, NW portion, in deep and ultra-deep waters, Brazilian Equatorial Margin

A petroleum geology study was carried out at Foz do Amazonas Basin northwest portion, a new exploratory frontier basin on the Brazilian Equatorial Margin. Seismic and well data were interpreted to search similar play of some oil discoveries in correlated basins. The study area is in deep/ultra-deep waters, where the influence of the Amazon Cone is less expressive and 90 km east of Zaedyus oil discovery on Guiana-Suriname Basin. There were interpreted four seismic horizons, four chronostratigraphic intervals, two hypothetical petroleum systems, two exploratory Cretaceous plays, and an estimative of the source rock maturity. The petroleum systems are: Cassiporé/Codó–Limoeiro (late Aptian-Late Cretaceous) and Limoeiro–Limoeiro (Cenomanian/Turonian-Late Cretaceous). The top seismic horizons interpreted are Basement, Albian, Cretaceous, and Middle Miocene, determining four chronostratigraphic intervals: Early Cretaceous, Late Cretaceous, Paleocene to Middle Miocene, and Late Miocene to Recent. There were interpreted two Cretaceous plays: Slope to Plain and Deep/Ultra-Deep Waters. The main source rocks are the shales of the Codó Formation (late Aptian) and Limoeiro Formation (Cenomanian-Turonian). The Codó Formation reaches 10% TOC, has Type I kerogen, excellent potential for oil generation, and thermal maturity. The Limoeiro Formation may have 4,4% TOC, Type II kerogen, and very good petroleum potential. The reservoir rocks are Late Cretaceous Limoeiro Formation turbiditic sandstones. The seal rocks are marine shales from Late Cretaceous Limoeiro Formation. The traps are mainly stratigraphic (pinch-out). The migration routes are mainly lateral or, exceptionally, vertical, where the faults are present. The estimated source rock maturity indicates that at least one of them is below the oil window top. It was concluded that there is a great hydrocarbon exploratory potential to this part of the basin, similar to the discoveries that occurred in the correlated basins of the equatorial margins of Africa and South America.

Insights into sedimentary provenance and the evolution of the Potiguar Basin, NE Brazil, using U–Pb ages and Lu–Hf isotopes in detrital zircons

U–Pb and Lu–Hf data obtained from detrital zircon of 21 samples from four wells were used to determine the source terrains of the Cretaceous sedimentary rocks of the Pendência, Pescada and Alagamar Formations (rift and post-rift sections) of Potiguar Basin, northeast Brazil. More than 1500 U–Pb concordant ages allowed the determination of the main age peaks in Paleoproterozoic (ca. 2.2–2.0 Ga and 1.9–1.7 Ga) and Neoproterozoic (ca. 0.62–0.55 Ga), matching the ages of rocks from the basement adjacent to the basin (northern portion of Borborema Province). εHf values obtained from 61 zircon grains range from −0.53 to −8.86 for Paleoproterozoic and from 7.67 to −25.43 for Neoproterozoic zircons, consistent with published data from rocks of the adjacent basement. Neoproterozoic zircons shows εHf values more negative from bottom to top, and presents a trend in U–Pb age vs εHf where the older grains show juvenile signature and the younger, continental crustal signature. This trend mimics the evolution of granitoid generation in the basement adjacent to the Potiguar Basin during the Neoproterozoic orogeny. The age pattern varies vertically in most wells, reflecting the contribution of distinct source areas following the rift evolution. Furthermore, the age pattern in the wells located at southeast of the grabens and horsts system of the onshore Potiguar Basin show Paleoproterozoic zircons concentrated in a single peak age, few or no zircon grains of 1.8–1.6 Ga and lesser amount of 0.6–0.7 Ga zircons, in contrast with the wells located at northwest, with Paleoproterozoic ages distributed in more than one peak, significant presence of 1.8–1.6 Ga zircons and proportionally more 0.6–0.7 Ga zircon grains. It suggests that this system acted as a barrier to sediment transport, delimiting the basin in two sectors fed by two different sources, one being the northeast portion of Borborema Province and the other, the northwest portion, both in the rift and post-rift sections. Such differences can result in distinct quality for the potential reservoirs in these sectors and would be an important guide for hydrocarbon exploration in Potiguar basin.

Geochronology and geochemistry of the Yidi'nan quartz diorite in the West Qinling, China: Implications for evolution of the Palaeo‐Tethys Ocean

The Xiahe‐Hezuo polymetallic district, located the northwest portion of the West Qinling orogen, has a wide distribution of granitoid rock. Thus, information on the widespread Triassic granitoids in this area is important to constrain the tectono‐magmatic processes. However, the tectonic setting and genetic mechanism for the granitoids in this area are still controversial. In this study, we present a detailed description of zircon U–Pb ages, whole‐rock geochemistry, and Hf isotopes for the Yidi'nan quartz diorite and elucidate their petrogenesis and geodynamic implications. The quartz diorite was crystallized at 240.6 ± 1.8 Ma, based on its zircon U–Pb age. The quartz diorite belongs to the high‐K calc‐alkaline, metaluminous, I‐type granites and its fractionated REE patterns show enrichment of Rb, U, and Th, depletion of Ba, Sr, Nb, and Ta, and negative Eu. The zircons have negative εHf(t) values in a range of −7.66 to −2.72, corresponding to two‐stage model ages ranging from 1.66 to 1.48 Ga. The integrated data from petrology, geochronology, and bulk geochemistry suggest that the quartz diorite is formed along an active continental margin, and from the partial melting of the Lower Proterozoic crust. It is associated with the Palaeo‐Tethys oceanic crust that suffered northward subduction beneath the South Qinling Block from Permian to Early Triassic.

Evapotranspiration Estimation Based on Remote Sensing and the SEBAL Model in the Bosten Lake Basin of China

Evapotranspiration (ET) is an important part of both water balance and energy balance. Accordingly, the estimation of ET plays a key role in research related to regional water resources and energy balance. Using the largest inland freshwater lake in China—Bosten Lake Basin—as a target area, this study employs the SEBAL model combined with actual surface ET from the 2013 MODIS ET data to estimate ET in the Bosten Lake Basin from a time and space perspective. The findings include the following: (1) Evapotranspiration in the Bosten Lake Basin shows a unimodal distribution in terms of time distribution, with the highest ET occurring in July and August. In terms of spatial distribution, the overall trend is more apparent in the northwest portion of the basin than the southeast portion, as there are more mountains in the northwest as well as fewer desert areas. (2) Grassland and unused land were the main types of land cover, and ET exhibited a clear relationship to vegetation coverage and water supply. The distribution of land use types from northwest to southeast ET show a significant downward trend. (3) During the growing season, the average daily ET level of land use/cover type was the greatest over water bodies (5.61 mm/d), followed by grassland (4.6 mm/d) and snow/ice (4.29 mm/d), with unused land giving the smallest amounts of ET.