Northeast Direction Research Articles

Diamond-bearing lithosphere of the Siberian platform (based on geophysical data). Precambrian heredity, Paleoproterozoic plume magmatism, diamond content of the Anabar tectonic province

In the first part of the article [15], we presented the results of the analysis of the structural relationship of prospective areas and tectonic zonation of the Siberian Platform (SP). Here we demonstrate the reflection of the heredity of structural-material complexes (SMC) of the Precambrian basement of the SP to the Paleoproterozoic mantle-plume events in the geophysical fields. The analysis of the attributes of the prospective areas, as images of the SMC of the deep Precambrian, made it possible to determine the area of maximum thermal-mantle impact on the SP Precambrian lithosphere of the Early Proterozoic superplume, as well as its presumed center in the northwestern segment of the SP. The spatial distribution of the attributes, revealing the correlation of the components with the prospecting areas, contributed to the refinement of the position of the system of orthogonal lineaments on the SP, in general, corresponding to the framework reported in Basharin’s work [3]. The published geological and geophysical materials and the results of processing geophysical data showed that the deep structure of the central part of the Anabar tectonic province (AN) has the attributes characteristic of the Archean diamondiferous cratons. This can indicate the presence of a diamondiferous lithospheric root within AN. The southwestern segment of AN corresponds with the position of the Angara-Vilyui ore belt (AVRP) [2], which, along with other data, can allow us to extend the ore belt in the northeast direction, as well as recognize it in the rank of the Siberian diamond province. The prospects for the discovery of new industrial-diamond-bearing kimberlite fields are associated with the territory of the AN, the positions of the diamond-bearing lithospheric root, zones of deep crustal-mantle faults within it and its boundaries.

AGE AND TECTONIC SETTING OF THE KOPRI-TYPE GRANITOIDS OF THE JUNCTION ZONE OF THE DZHUGDZHUR-STANOVOY AND WEST-STANOVOY SUPERTERRANES OF THE CENTRAL ASIAN FOLD BELT

Geochemical, geochronological (U-Pb on ID TIMS zircons), and isotope-geochemical (Sm-Nd) studies of the Kopri-type granitoids of the Tukuringra Complex have been done. The granitoids localized exclusively in the zone of the Dzheltulak suture, which separates the Dzhugdzhur-Stanovoy and West Stanovoy superterranes of the Central Asian fold belt. It has been established that they can be classified as postcollision granitoids of elevated alkalinity and basicity of the adakite type, formed in the age range of 127 ± 1–126 ± 1 Ma, which are part of the Late Mesozoic postcollision Stanovoy volcano-plutonic belt extending in the sublatitudinal direction from the Sea of Okhotsk inland continent subparallel to the Mongolo-Okhotsk suture zone for more than 1000 km and stitching the Dzhugdzhur-Stanovoy and West- Stanovoy superterranes. The structural position of massifs of the Kopri-type granitoids fixes the upper age boundary of the formation of the Dzheltulak suture. The formation of the initial magmas of these granitoids is connected with an essentially lithospheric source formed as a result of mixing of the Early Precambrian and younger, apparently, Phanerozoic component. The similarity in the Nd isotopic composition of the granitoids of the Kopri-type with similar in composition and age granitoids of the West Stanovoy superterrane most likely indicates the similarity of their sources, as well as the fact that the Dzheltulak suture zone “plunges” in the northeast direction under the structures of the Dzhugdzhur–Stanovoy superterrane. This is in full accordance with modern ideas about the features of the deep structure of the junction of the Eurasian and Amur lithospheric plates.

Organic molecular markers in PM2.5 on a tropical island in the South China Sea: Temporal variations, sources, and process implications

Organic aerosols (OA) in marine environments can be derived from various origins. However, fundamental temporal variations of marine OA are lacking, leading to an insufficient understanding of their sources and atmospheric processes. In this study, numerous organic molecular markers in fine aerosols were measured on a tropical island in the South China Sea (SCS) for one year to examine their occurrence, temporal variations, sources, and atmospheric transport. Differences in the temporal variations of these compounds, depending on their input pathways were observed. The carbon preference index indicated that diesel and gasoline exhausts are the main sources of n-alkanes. The backward trajectory showed that the occurrence of levoglucosan (the dominant anhydrosugar) was associated largely with air masses from East Asia delivered by the monsoon. Glucose and galactose in the aerosols mainly originated from biogenic sources in the tropical regions. The temporal pattern of stearic acid and palmitic acid, the dominant fatty acids (FAs), was highly monsoon-dependent and associated with atmospheric inputs. Sea salt aerosols (SSA) were considered the primary origin of the FAs. Four main sources (biomass burning, biogenic organic aerosols, sea salt aerosols, and vehicle and vessel exhaust) of these markers at this island were identified by principal component analysis. The Concentration Weighted Trajectory (CWT) model revealed that the source regions were mainly associated with the northeast and southwest directions of the island as well as from local emissions. Specific ratios and relationships of/between the organic molecular markers in the aerosols also implied strong compound-selective atmospheric loss, which needs to be validated.

Multiwavelength study of NGC 1365: The obscured active nucleus and off-nuclear compact X-ray sources

ABSTRACTWe present a multiwavelength study of the active nucleus and the off-nuclear X-ray sources in the nearby spiral galaxy, NGC 1365 using three simultaneous UV/X-ray observations by AstroSat over a two months period and archival IR observations performed with Spitzer and Herschel. Utilizing the data from the Soft X-ray Telescope (SXT) onboard AstroSat, we find spectral variability mainly caused by the variation in the X-ray column density, (NH ∼ 1022–1023 cm−2). With the accurate spatial resolution of the UVIT onboard AstroSat, we separate the intrinsic AGN flux from the host galaxy emission and then correct for the Galactic and the internal reddening. We detect no significant variation in the NUV emission over the observation period. The AGN in FUV band is undetectable due to heavy intrinsic extinction. Further, the multiwavelength IR/UV/X-ray AGN SED reveals that the AGN is in a low-luminosity phase with accretion rate ∼0.01 LEdd. The steady UV emission and strong X-ray absorption variability suggest that the obscuring clouds are likely compact and affect the compact X-ray source only and do not possibly cover the extended UV emitting region. In addition, the UVIT is able to resolve two bright spots at a radius of 7 arcsec (∼6.3 Kpc) from the central nucleus in the South-West (SW) direction. In the UVIT image of the entire galaxy, we identify UV counterparts to four Chandra identified bright X-ray sources. One well-known ultra-luminous X-ray source (ULX) NGC 1365 X2 is identified with its UV counterpart at 86 arcsec from the nucleus in the North-East (NE) direction from the active nucleus.

Analysis of the relationship among land surface temperature (LST), land use land cover (LULC), and normalized difference vegetation index (NDVI) with topographic elements in the lower Himalayan region

Land Surface Temperature (LST) affects exchange of energy between earth surface and atmosphere which is important for studying environmental changes. However, research on the relationship between LST, Land Use Land Cover (LULC), and Normalized Difference Vegetation Index (NDVI) with topographic elements in the lower Himalayan region has not been done. Therefore, the present study explored the relationship between LST and NDVI, and LULC types with topographic elements in the lower Himalayan region of Pakistan. The study area was divided into North-South, West-East, North-West to South-East and North-East to South-East directions using ArcMap 3D analysis. The current study used Landsat 8 (OLI/TIRS) data from May 2021 for LULC and LST analysis in the study area. The LST data was obtained from the thermal band of Landsat 8 (TIRS), while the LULC of the study areas was classified using the Maximum Likelihood Classification (MLC) method utilizing Landsat 8 (OLI) data. TIRS collects data for two narrow spectral bands (B10 and B11) with spectral wavelength of 10.6 μm–12.51 μm in the thermal region formerly covered by one wide spectral band (B6) on Landsat 4–7. With 12-bit data products, TIRS data is available in radiometric, geometric, and terrain-corrected file format. The effect of elevation on LST was assessed using LST and elevation data obtained from the USGS website. The LST across LULC types with sunny and shady slopes was analyzed to assess the influence of slope directions. The relationship of LST with elevation and NDVI was examined using correlation analysis. The results indicated that LST decreased from North-South and South-East, while increasing from North-East and South-West directions. The correlation coefficient between LST and elevation was negative, with an R-value of −0.51. The NDVI findings with elevation showed that NDVI increases with an increase in elevation. Zonal analysis of LST for different LULC types showed that built-up and bare soil had the highest mean LST, which was 35.76 °C and 28.08 °C, respectively, followed by agriculture, vegetation, and water bodies. The mean LST difference between sunny and shady slopes was 1.02 °C. The correlation between NDVI and LST was negative for all LULC types except the water body. This study findings can be used to ensure sustainable urban development and minimize urban heat island effects by providing effective guidelines for urban planners, policymakers, and respective authorities in the Lower Himalayan region. The current thermal remote sensing findings can be used to model energy fluxes and surface processes in the study area.

Geo-visualization of Sarawak COVID-19 Publicly Available Data Employing Open-source Geospatial Software

The state government of Sarawak with the help of the Sarawak Disaster Management Committee (SDMC) has continuously made the updated information on the state COVID-19 situation and its ensuing control measures available to general public in the form of daily press statements. However, these statements are merely providing textual information on daily basis though the data are in fact rich in temporal and spatial properties. Since the onset of COVID-19 pandemic, spatiotemporal analysis becomes the key element to better understand the spread of COVID-19 in various spatial levels worldwide. Hence, there is an urgent need to convert this textual information into more valuable insights by applying geo-visualization techniques and geospatial statistics. The paper demonstrates the prospect of retrieving geospatial data from publicly available document to locate, map and analyze the spread of COVID-19 up to division level of Sarawak. Specifically, map visualization and geospatial statistical analysis are performed for the list of exposed locations, which are indeed locations visited by COVID-19 patients prior to being tested positive in Kuching division, using open-source geospatial software QGIS. It is found that these exposed locations concentrate on the build-up areas in the division and are in south-west to north-east direction of the center of Kuching in September and October 2021. Despite the number of exposed locations published is relatively small compared to the number of confirmed cases reported, both are nearly strongly correlated. The insights gained from such geospatial analysis may assist the local public health authorities to impose applicable disease control interventions at division level.

Home ranges, directionality and the influence of moon phases on the movement ecology of Indian flying fox males in southern India.

Flying foxes of the genus Pteropus are amongst the largest fruit bats and potential long-range pollinators and seed dispersers in the paleotropics. Pteropus giganteus (currently P. medius) is the only flying fox that is distributed throughout the Indian mainland, including in urban and rural areas. Using GPS telemetry, we mapped the home ranges and examined flight patterns in P. giganteus males across moon phases in a semi-urban landscape in southern India. Home range differed between the tracked males (n=4), likely due to differences in their experience in the landscape. We found that nightly time spent outside the roost, distance commuted and the number of sites visited by tracked individuals did not differ significantly between moon phases. In 61% of total tracked nights across bats, the first foraging site was within 45˚ of the emergence direction. At the colony-level, scan-based observations showed emergence flights were mostly in the northeast (27%), west (22%) and southwest (19%) directions that could potentially be related to the distribution of foraging resources. The movement ecology of fruit bats in relation to the pollination and seed dispersal services they provide requires to be investigated in future studies. This article has an associated First Person interview with the first author of the paper.

Proper Motions of Water Masers in W49 N Measured by KaVA

We report the proper motions of 22 GHz water masers toward W49 N that were observed by the KVN and VERA Array (KaVA) during 2017 February–May. We found 263, 268, and 310 features in three successive epochs; they were distributed in a region of size 4 × 4 arcsec2. The strongest flux density was in the third epoch, and its averaged value was 18,090 Jy at V LSR +0.47 km s−1. For 102 H2O maser features, proper motion was detected across all three epochs. The average proper motions in R.A. and decl. offset were −0.352 and +0.890 mas yr−1, respectively. The morphology of the distribution of the H2O maser features was found to be a bipolar outflow structure with an inclination angle of 37° ± 13° to the line of sight, and the features were expanding from a well-defined outflow center. A model of the source combining expansion and rotation yielded a distance to W49 of 11.12 ± 0.96 kpc that is consistent with the results from trigonometric parallax. A redshifted lobe was situated in the northeast direction and a blueshifted lobe in the southwest direction. We also discussed the location of the powerful flaring H2O maser feature at V LSR = + 6 km s−1 and its possible mechanisms on the basis of spatial structures for the maser feature in VLBI maps observed with the KaVA, timed just before and during the rebrightening phase.

Crustal study based on integrated geophysical techniques in the Northwestern Himalayas, Pakistan

The present research aims to explicate the tectonics of the northwest Himalayas, Pakistan, based on integrated gravity, magnetic and earthquake data. The raw gravity and magnetic data were processed, and seven isoanomaly maps were prepared for qualitative interpretation, whereas a gravity model was prepared along the selected profile for quantitative interpretation. The local earthquake data have also been used to identify the various seismogenic layers in the subsurface and to understand how seismicity relates to regional structural features. Three northwest‐trending thick‐skinned blind basement faults are identified from the present study, namely the Indus Kohistan Seismic Zone (IKSZ), Bagh Basement Fault and Hazara Lower Seismic Zone. The IKSZ is the tectonically most active among them and responsible for the 2005 Kashmir earthquake (Mw = 7.6) and 1974 Pattan earthquake (Mw = 6.2) in the region. The present study also delineated the prominent location of the Main Central Thrust in which the high‐grade metamorphic rocks of Higher Himalayan Crystalline thrust over low‐grade metamorphic rocks of Lesser Himalayas along this thick‐skinned fault. The field evidence such as ductile deformation, zone of inverted metamorphism, and brittle deformation also confirm this location. The sharp bending of the crystalline crust, as well as deep basement just south of Kohistan Island Arc (KIA), indicate that the high density and susceptibility rocks of this arc thrust on the leading margin of the Indian Plate along the Main Mantle Thrust. This thrust fault is a major suture zone separating the KIA in the north from the Indian Plate in the south. The other faults in the region exist in the sedimentary/meta‐sedimentary wedge and are thin‐skinned. It is inferred from the current investigation that the study area exhibits a composite style of deformation. Moreover, the gravity model combined with earthquake data suggested the existence of multiple décollement zones below the Hazara‐Kashmir Syntaxis. The model envisaged an increase in the thickness of the Indian Plate continental crust in the northeast direction.

Hydrothermal Reservoir and Electrical Anisotropy Investigated by Magnetotelluric Data, Case Study of Asal Rift, Republic of Djibouti

At the center of the Republic of Djibouti, an eroded rift called Asal is located where tectonic and magmatic activities can be observed at the surface. Multiple studies were carried out with different exploration methods, such as structural, geophysical and hydrogeological, to understand rifting processes and characterize the subsurface of this rift. Among these subsurface exploration methods, the deep geoelectrical structures need to be better defined with the magnetotelluric (MT) method to better delineate the deep resistivity structures. With the objective of improving our understanding of the deep rift structure, magnetotelluric (MT) data acquired in the Asal rift were analyzed and inverted to build a 2D electrical conductivity model of the hydrothermal system. To achieve this, a dimensionality analysis of the MT data along a 2D profile perpendicular to the rift axis was carried out. Results of this analysis justify the approximation of 2D conductivity structure. Then, 2D inversion models were achieved to build models of the conductive structures. Dimensionality analysis results revealed the existence of electrical anisotropy. Consistent correlation between geoelectric strike and electrical anisotropy direction was suggested. Electrical anisotropy direction determined from the ellipticity of the phase tensor for the short periods was interpreted as the consequence of tectonic activity and horizontal deformation of the rift. Moreover, electrical anisotropy direction for the long periods was assumed to be related to the effects of combined magmatic-tectonic activities with predominant magma/dyke intrusion, which implies the vertical deformation and the subsidence of the rift and may imply the alignment of Olivine. Moreover, the variation and rotation of paleo and recent stress fields direction of plate motion in Asal rift located at the junction of three diverging plates—Arabia, Nubia and Somalia—over geological time can generate both magmatic and tectonic activities which in turn can induce a preferred direction of electrical anisotropy which is the direction of the highest conductivity. While the north-south electrical anisotropy direction is parallel to the direction of Red Sea Rift propagation, the north-east electrical anisotropy direction is aligned with the extension direction between Arabia and Somalia plates. Results of the 2D inversion models presented for the Asal rift allowed to identify two superimposed conductive units close to the surface and are interpreted as a shallow aquifer and a wide potential hydrothermal system. These conductive mediums are overlying a relatively resistive medium. The latter is associated with a magmatic system likely containing hot and/or partly molten rocks. The 2D conductivity model developed in this study could be considered as conceptual model of Asal rift prior to modeling multiphase fluid flow and heat transfer and/or could be used to identify the hydrothermal system for future drilling target depth of geothermal exploration.

Rupture Process of the 2017 Mw 5.5 Pohang, South Korea, Earthquake via an Empirical Green’s Function Method

ABSTRACTThe Mw 5.5 earthquake occurred in Pohang, South Korea on 15 November 2017, which is known as a “runaway earthquake,” and was triggered from a critical-state fault as a result of fluid injection. As such earthquakes rarely occur, spatiotemporal slip distributions were investigated via the finite-fault inversion based on the empirical Green’s function in this study. The rupture process can be divided into three steps: first, slip initiated and propagated only to the southwest from the hypocenter during the initial 0.6 s; in the second step from 0.6 to 2.4 s, the slip occurred to the southwest and northeast parts, in which the maximum seismic moment was released; in the third step from 2.4 to 6.0 s, slip occurred around the edge of the fault plane farther from the hypocenter, particularly in the deep part in the northeast direction. In each step, the seismic moment was released as approximately 6%, 59%, and 35%, respectively. The first step can be interpreted not as a part of the rupture process of the mainshock but as the immediate and distinct foreshock. Overall, most of the slip distributed southwest is consistent with the results of the directivity analysis using apparent source time functions. Although the average stress drop (~1 MPa) of the Pohang earthquake is considerably lower than that (~20 MPa) of the Mw 5.5 Gyeongju earthquake that naturally occurred in the vicinity of the Pohang, it is difficult to attribute it only to the fluid injection effect. Through this study, we improve our comprehension of the seismic source physics and mechanisms of the Pohang earthquake by analyzing the spatiotemporal slip history, the directivity of rupture process, and the spatial distribution of the stress drop on the fault plane.

Faults of the Pre-Baikal submontane trough (Siberian Platform): Structural-genetic analysis

Research subject. The pre-Baikal submontane trough is located in the eastern part of the Irkutsk Amphitheater of the Siberian Platform, stretching for 600 km in a north-easterly direction. The trough started to form in the Mesozoic on the Paleozoic folded base and continued in the Cenozoic. The trough is characterized by a complex structure of shafts and deflections complicated by ruptures.Aim. To investigate the insufficiently studied ruptures of the platform cover, which are difficult to map due to minor displacements of their wings.Materials and methods. The method of specialized mapping of crustal fault zones based on a analysis genetically related of ruptures families was used. A network of 18 points of geological and structural observations in rocks of different ages of the sedimentary cover was created.Results. A rank structural-genetic analysis of fractures mapped in rocks of different ages and composition revealed specific features associated with the gradual development of the trough. The ruptures identified in the rocks of the pre-Cenozoic cover of the platform satisfy the parageneses of the compression zone, the dextral strike-slip zone and the extension zone of the north-eastern strike. Deformations in Cenozoic sediments belong to the parageneses of dextral strike-slip zone and the extension zone. These parageneses consist of strike-slip and normal faults.Conclusions. The Cenozoic Pre-Baikal submontane trough was formed under strike-slip and extension conditions. The compression stage is highlighted in the Pre-Cenozoic base.

Movement patterns and growth rate of Scotsman Polysteganus praeorbitalis (Sparidae) tagged in the Pondoland Marine Protected Area, Eastern Cape, South Africa

A tag-recapture study was undertaken on Polysteganus praeorbitalis in the Pondoland Marine Protected Area (PMPA) on the east coast of South Africa. A total of 1 042 fish were tagged over a period of 16 years and 255 individuals (24.5%) were recaptured, some of them on multiple occasions. Data analysis showed that 84.7% of recaptured fish remained in relatively small home ranges (-750 m linear distance), while 13.3% abandoned their home ranges and undertook unidirectional movements (of 21-1 211 km) along the KwaZulu-Natal coast in a north-easterly direction, most likely to spawn. While the no-take area of the PMPA provides effective protection for resident fish, the export of adult P. praearbitalis provides strong evidence of the benefits that no-take MPAs can offer to adjacent fisheries. Based on the tag-recapture length data, the growth rate was found to be relatively slow, averaging 46 mm y-1. This growth rate was similar to that determined by a study of ageing using sectioned otoliths. Reliable tag-recapture data can thus be used to provide a valuable means of validating growth rates determined by other methods.

High-Inclination Coring of Chang-63 of the Yanchang Formation in Huaqing Oilfield, Ordos Basin: Implications for Ancient Flow Direction and Fracture Orientation

A promising method is to use coring of high-inclination well to find ancient flow direction and orient tiny natural fractures in massive sandstone of sandy debris flow. Determination of ancient flow direction can reduce the number of exploration wells, and orientation of natural fractures is of guiding significance to the deployment of water injection development well pattern. In Block X of Huaqing Oilfield, Ordos Basin, the cores of Chang 63 section were obtained from Well Y through 16 coring operations, with a total length of 105 m. Cores is oriented through drilling parameters, the number of cores, the angle between the core edge and horizontal bedding, the coincidence degree of core profile and directional flame structure. Therefore, the micro-fractures on the core are directional. The ancient flow directions of sandy debris flow were restored by load casting, groove casting, groove casting and imbricate structure. Our results show that the ancient flow directions of sandy debris flows were southwest, southeast, northwest, and west from bottom to top. The front of the Wuqi Delta is the main source of blocky sandstone with the best oil-bearing property. Affected by the topography of the lake bottom, the sandy debris flow turned locally in the northeast direction, and the sandy debris flow from this direction was formed. The NEE-SWW-trending fractures formed in the Yanshanian period are most developed in the Huaqing area, which should be considered in deploying the flooding well network. The north-south micro-fractures formed in the Himalayan period can improve the physical properties of tight sandstone, which is of great significance for tight sandstone reservoirs.

Impacts of climate change on hulless barley security in plateau region: A case study of Lhasa River basin in Tibet, China

AbstractAccurate understanding of the impacts of climate change on hulless barley and river in the Lhasa River Basin is of great significance to food security and water resources management in the plateau region. It is important to explore the relationship between hulless barley and river under the background of climate change for the comprehensive and coordinated development of agriculture and water conservancy. Based on the Google Earth Engine (GEE) cloud computing platform, the Random Forest algorithm was used to obtain the spatio‐temporal variation of hulless barley and river in the Lhasa River Basin from 2010 to 2020. The overall accuracy and Kappa coefficient of classification results were 89.54% and 85.96%, respectively. The average area and Normalized Difference Vegetation Index (NDVI) of hulless barley from 2010 to 2020 were 178.46 km2 and 0.69, respectively. The increase of accumulated precipitation, number of precipitation days, average dew point temperature (ADPT) and average wind speed (AWS) promoted the growth of hulless barley, with NDVI significant increasing rate of 0.0173 (R2 = 0.764, p < 0.001). The combined effects of human activities (construction of water conservancy facilities and mining activities), ADPT and AWS resulted in a significant decrease (decreasing rate: 10.8682 km2/year, p < 0.01) in river area during 2010–2020. There was a significant negative correlation (R2 = 0.722, p < 0.01) between hulless barley NDVI and river area driven by climate factors. The changes in hulless barley gravity center and river gravity center were consistent, and both shifted in the northeast direction. These results provide a scientific understanding of the impacts of plateau climate change on agriculture and water resource. The land cover maps of the Lhasa River Basin with long time series and high spatial resolution were drawn. Our study verified the relevance between hulless barley gravity center and river gravity center as well as the internal relationship between hulless barley growth and river area. Furthermore, we explored the interrelation relationships among hulless barley, the Lhasa River area and climate factors.

ORE-BEARING OF THE LIVOBEREZHNY ZIRCON-RUTILE-ILMENITE PLACER DISTRICT

The relevance of the presented publication is due to the need to highlight the current state of zirconium-titanium specialization objects, the need to modernize and unify geological information, due to the significant increase in the world community’s interest in minerals that belong to the group of critical raw materials. The article presents generalized data on the ore-bearing zircon-rutile-ilmenite deposits of the Livoberezhniy placer district of the Ukrainian placer province. This area has unique paragenetic characteristics, as it is located in the junction zone of three geostructural units: the Dnipro-Donetsk depression, the northeastern slope of the Ukrainian crystalline shield, and the Kalmius-Toretsk depression of Donbas. The Livoberezhniy placer district includes the Vovchansk, Voskresenivsk, Southern, Nova-Mykolaivka, North-Samarsk, Yuriivsk and Petropavlivsk zircon-rutile-ilmenite deposits. These deposits are located in the sediments of the Bereka and Novi Petrivtsi suites. The Petropavlivsk and Yuriivsk deposits have a two-layer structure, the rest is belongs to the deposits of the only Novi Petrivtsi suite. The genesis of deposits is buried coastal-marine placers. All deposits have a slight dip of the ore sand layers in a north-east direction, which outlines the general slope of the water basin floor. Today, the Vovchansk zircon-ilmenite-rutile deposit is being developed by DEMURINSKY GZK LLC. On the basis of the results of geological prospecting and geological exploration conducted in the 60s and 70s of the last century, maps of the strength of the ore stratum and the distribution of ore components (ilmenite, rutile, zircon) were constructed. The visualization data was built for the Voskresenivsk, Southern, Nova-Mykolaivka, North-Samarsk, Yuriivsk and Petropavlivsk deposits. An analysis of the obtained data was carried out and a number of conclusions were drawn regarding the distribution of ore components for each of the deposits.

Spatio-temporal interaction heterogeneity and driving factors of carbon emissions from theconstruction industry in China.

Global warming caused by carbon emissions has become a major issue that countries need to address. As the largest carbon emitter globally, the construction industry is one of the major contributors to carbon emissions in China. It is of significance for carbon reduction to study carbon emission from construction industry. Based on various methods, this study explored the spatio-temporal characteristics of carbon emissions and the driving factors of construction industry. This study found, in 2007, 2010, and 2012, carbon emissions from the construction industry exhibited an increasing trend, and the indirect carbon emissions accounted for approximately 77% of the total carbon emissions overall; in addition, the regional gaps in carbon emissions are widening. The space centers of gravity of direct, indirect, and total carbon emissions showed similar rotations in the counterclockwise direction and gradually shifted to the northeast direction. Carbon emissions from the construction industry were predominantly influenced by the total population, number of employees in construction industry, labor productivity in construction industry, added value of the construction industry, energy consumption in construction industry in 2007, evolution to the mutual influence of the total population, labor productivity in construction industry, and energy consumption in construction industry in 2012. The finds can make references for the regional sustainable development.

Source rupture characteristics of the September 5, 2022 Luding MS 6.8 earthquake at the Xianshuihe fault zone in southwest China

On September 5, 2022, at Beijing time 12:52 p.m., an MS 6.8 earthquake struck Luding County, Garze Tibetan Autonomous Prefecture, Sichuan Province. The epicenter of the earthquake was at the intersection of the Sichuan-Yunnan, Bayankala, and South China blocks. The tectonic background is extremely complex, and strong earthquakes occur frequently. Based on a predetermined focal location and focal mechanism solution for the earthquake, we reversed the focal depth and rupture process of the earthquake by fitting the teleseismic P and SH waves recorded by the global seismic network. The results show that the focal depth is 16 ​km, with the main rupture having a length of about 45 ​km near the epicenter, with a maximum displacement of 1.02 ​m. Although the rupture mainly propagates from the north–northwest (NNW) to the south–southeast (SSE) along the fault strike, there is a small-scale rupture slip zone at shallow depths in the north–northeast (NNE) direction along the epicenter of the seismogenic fault. This rupture image corresponds to the cluster distribution of aftershocks in the NNW and SSE directions starting from the epicenter, corresponding to the distribution of recorded landslides. The earthquake occurred on the Moxi fault, located in the southeastern section of the Xianshuihe fault. The major tectonic feature in this area is the southeastward movement of the Chuandian block relative to the Bayanhar block.

DISPERSION OF SO2 AND NO2 EMITTED BY AUXILIARY BOILER OF PT KMI METHANOL INDUSTRIAL USING THE GAUSSIAN PLUM MODEL AERMOD IN BONTANG CITY EAST KALIMANTAN INDONESIA

The petrochemical industry PT Kaltim Methanol Industri Bontang City, uses auxiliary boilers with natural gas fuel and is connected to the stack to emit pollutants into the atmosphere. The objectives of this study are SO2 modeling with a radius of 5 kilometers and modeling of NO2 with a radius of 10 kilometers from the emission source. Modeling using AERMOD software, AERMET Software, and Aermap ArcGIS Software. The wind rose in the dominant research area from the southwest and northeast directions. Dispersion of SO2 and NO2 decreases according to the distance. The increase in concentration occurred in areas that experienced elevation increases, in Teluk Pandan District with a distance of about 10 kilometers northwest with an elevation of about 100 meters above sea level, and part of the West Bontang District with a distance of about 5 kilometers to the southwest with an elevation of about 90 meters above sea level. The maximum concentration of SO2 at the receptor was 6.2631 μg/m3 on hourly modeling, 0.58132 μg/m3 on modeling per 24 hours, and 0.0317 μg/m3 on annual modeling. The maximum NO2 concentration at the receptor was 1.96781 μg/m3 on hourly modeling, 0.18089 μg/m3 on hourly modeling, and 0.01002 μg/m3 on annual modeling. The distribution of pollutants based on hourly modeling per 24 hours is spreading in all directions and irregularly while for annual modeling it tends to spread towards the southwest and northeast according to the wind rose.Keywords: AERMOD, Emissions, Modeling, Air Dispersion, Auxiliary boiler

Multi-scenario simulation of land use/cover change and carbon storage assessment in Hainan coastal zone from perspective of free trade port construction

Accurate prediction of future Land Use/Cover Change (LULCC) and its impact on ecosystem carbon storage is of great scientific significance for regional land use decision making and carbon management. However, there are few previous studies that combine spatial and temporal scales to explore the impact of future land use changes on ecosystem carbon storage in coastal zones at the provincial scale. Taking the coastal zone of Hainan Island as an example, Landsat TM (OLI) data from 1990, 2000, 2010 and 2020 were used as the main data sources to analyze the spatial and temporal evolution of land use from 1990 to 2020. The GeoSOS-FLUS model was used to predict land use patterns under baseline, development priority and ecological priority scenarios in 2030. Based on land use data, ArcGIS and Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) models were used to evaluate the carbon storage of ecosystems from 1990 to 2030, to explore the spatial and temporal evolution of LULCC and response of the LULCC to carbon storage, and to reveal the process and mechanism of the impact of the complex land use change process on the carbon sink service function of regional ecosystems in tropical and subtropical coastal zones. The results showed that: 1) From 1990 to 2020, the area of cropland, forest land, grassland and unused land decreased, while the area of water and built-up land increased. Unused land and cropland area continues to decrease, built-up land continues to increase. 2) LULCC has led to a continuous decrease in regional carbon storage over 30 years, reaching 1.5 × 106 t, with an annual change rate of 5.0 × 104 t/a. The extensive expansion of built-up land and the degradation of forest land are significant reasons for the decrease in carbon density, and “unused land→grassland” is the most obvious reason in the carbon storage increase. “Grassland→forest land (artificial)" is the most significant mapping reason in the decrease of carbon storage. The spatial and temporal characteristics of regional carbon storage showed a significant positive correlation with the region, and the wetland and mangrove areas in the southwest and northeast directions were the high-high concentration areas of carbon storage. 3) The built-up land in 2020–2030 shows different degrees of expansion in the baseline, development priority and ecological priority scenarios, with an increase of 1.94%, 2.13% and 0.70% respectively, and the development priority scenario has the largest increase. The cropland showed a shrinking trend in 3 simulated scenarios, and the area decreased by 0.87%, 0.97% and 0.87%, respectively. 4) The regional carbon storage in 2020–2030 decreases significantly under the baseline and development priority scenarios, at 1.29 × 105 t and 2.45 × 105 t respectively, while it increases significantly under the ecological priority scenario, at 1.34 × 105 t. The ecological priority scenario can effectively enhance the carbon sink capacity and control the reduction of cropland area. Optimizing the land use structure, controlling the growth rate of built-up land and increasing the area of forest land can have a positive effect on the development and use of coastal zone space and the carbon cycle.