Deep Source Research Articles

In-situ trace elements and sulfur isotopic analyses of stibnite: Constraints on the genesis of Sb/Sb-polymetallic deposits in southern China

The Xiangzhong metallogenic province (XZMP), the largest polymetallic mineralization province in southern China, is known for its large number of Sb and Sb-polymetallic deposits (>100). In this study, detailed microscope observation, trace element, and sulfur isotopic analyses were performed on stibnite from the Xikuangshan, Woxi, and Banxi deposits in the XZMP to constrain the ore genesis.Stibnite from three deposits appears similar under backscattered electron imaging and has similar major elements contents. Detectable trace elements in stibnite are Fe, Cu, Zn, As, and Pb. Base metals (Cu, Pb, and Zn) are enriched in stibnite from the Woxi deposit but are depleted in stibnite from the Xikuangshan and Banxi deposits. Gold is detectable only in stibnite from the Woxi deposit. Cu, As, and Pb mainly occur as solid solutions within the crystal lattice in stibnite, while micro-scale inclusions of Fe- and/or Zn-rich phases are also observed. The δ34S values of stibnite from three deposits are distinct but with narrow ranges: +6.8 to +10.2 ‰; +5.5 to +6.5 ‰; −4.2 to +0.1 ‰ for the Xikuangshan, Banxi, and Woxi deposits, respectively. The δ34S values of stibnite suggest that the underlying basement rocks are the potential source of sulfur for the Sb mineralization in the Xikuangshan and Banxi districts while sulfur for the Sb mineralization of the Woxi district may have originated from a deep magmatic source. In addition, a positive trend between the δ34S values of stibnite and sampling depth suggests an input of the 34S-rich basin brine during the mineralization in the Woxi district.We propose a genetic model for the Sb mineralization in the XZMP: Fluids rich in Sb, Au, W, Cu, Pb, and Zn related to igneous activities ascended via regional deep faults and mixed with 34S-rich basin brine. Ore minerals of Sb, Au, and W were deposited within structural traps resulting in the Woxi-type deposits. The basement-derived deep fluids driven by orogenic leached Sb and related metals from the basement metamorphic rocks, which migrated via the regional faults and mixed with cold near surface meteoric water to form the Xikuangshan-type deposits.

A New Methodology Combining Geophysical Calculations and Geological Analysis to Identify and Characterize Carrier Systems for Vertical Hydrocarbon Migration in the Central Diapir Zone of the Yinggehai Basin, China

To understand hydrocarbon migration in terms of the mechanisms, accumulations and exploration targets, it is essential to correctly identify and characterize the carrier systems that control fluid-migration history and oil/gas reservoir formation. The Yinggehai Basin in China is an important area for natural gas exploration and production. However, due to the argillaceous sand sedimentary environment and the absence of faults from the Neogene thermal subsidence period, traditional migration pathways are absent in the Yinggehai Basin, posing significant challenges to target evaluation in this area. Exploration shows that most of the existing gas reservoirs are associated with vertical migration. In this work, coherence cube and curvature seismic techniques are used in the central diapir zone of the Yinggehai Basin to identify diapir-associated fractures and regional stress. Together with geological analysis, two categories of carrier system are discussed in detail to explain the complex migration and accumulation patterns that have puzzled the area. Diapirs have five evolutionary phases, i.e., pressurization, piercing, equilibrium, release and collapse, which have different fracture development patterns, leading to different mechanisms of hydrocarbon migration and accumulation. The carbon isotopes of gaseous hydrocarbons in DF shallow layers and mid-deep layers have an inverted order distribution, indicating mixed accumulation with different maturity, whereas in the mid-deep layers of the diapir-affected areas, there is a single accumulation with low maturity. Early diapiric activity allowed the natural gas produced from deep source rocks to migrate upward along the diapiric carrier system and accumulate in suitable traps to form gas reservoirs. For regional-stress related fractures, the gradual loss of overpressure and fluids from deep to shallow in high-pressure fractures results in the gas accumulation time of deep traps in the regional stress-related carrier system being relatively late and the gas accumulation time of shallow traps being relatively early.

Assessment of possibility of finding geothermal energy resources around Mount Meru in northern Tanzania using classical solute geothermometry

This study uses classical solute geothermometry analysis to estimate the temperature and circulation depth of the geothermal reservoir around Mount Meru. Five springs affected by magmatic gases from a deep magmatic heat source are investigated; these include two hydrothermal springs. Results from silica geothermometers show that estimated reservoir temperatures range from 70 to 110 °C; this corresponds to a low-temperature hydrothermal system. Since Mount Meru is an active volcano, one would expect a high-temperature hydrothermal system; the low temperatures are ascribed to the mixing of hydrothermal and cold recharge waters. The geothermal reservoir is estimated to be about 1.3–1.4 km deep. Thus, the study shows that a low-temperature geothermal energy resource can be found on the eastern flank of Mount Meru.

Extracting the Invisible: Mesial Temporal Source Detection in Simultaneous EEG and SEEG Recordings.

Epileptic source detection relies mainly on visual expertise of scalp EEG signals, but it is recognised that epileptic discharges can escape to this expertise due to a deep localization of the brain sources that induce a very low, even negative, signal to noise ratio. In this methodological study, we aimed to investigate the feasibility of extracting deep mesial temporal sources that were invisible in scalp EEG signals using blind source separation (BSS) methods (infomax ICA, extended infomax ICA, and JADE) combined with a statistical measure (kurtosis). We estimated the effect of different methodological and physiological parameters that could alter or improve the extraction. Using nine well-defined mesial epileptic networks (1949 spikes) obtained from seven patients and simultaneous EEG-SEEG recordings, the first independent component extracted from the scalp EEG signals was validated in mean from 46 to 80% according to the different parameters. The three BSS methods equally performed (no significant difference) and no influence of the number of scalp electrodes used was found. At the opposite, the number and amplitude of spikes included in the averaging before the extraction modified the performance. Anyway, despite their invisibility in scalp EEG signals, this study demonstrates that deep source extraction is feasible under certain conditions and with the use of common signal analysis toolboxes. This finding confirms the crucial need to continue the signal analysis of scalp EEG recordings which contains subcortical signals that escape to expert visual analysis but could be found by signal processing.

Imaging of a shallow magma conduit system based on a high-power frequency-domain controlled-source electromagnetic survey

Mantle-derived magma may undergo lateral flow and emplacement through horizontal magma conduits; this occurs after magma from a deep source ascends through a vertical conduit. Regardless of this understanding, the characteristics of such shallow magma conduit systems remain unclear. We have developed an image of a shallow (5 km deep) magma conduit system based on the resistivity results of a high-power frequency-domain controlled-source electromagnetic survey in the Kalatongke magmatic-type Ni-Cu deposit. The magma upwelled and ascended along the vertical fault. At shallow depths, the magma moved horizontally along the tuff layer, laterally propagating in a horizontal magma conduit. Magma extending horizontally in the horizontal tuff layer could not break through the upper, conductive, and low-density carbonaceous layer. This image provides a conduit model with vertical magma ascent and lateral magma propagation. The model provides a basis for studying shallow magma conduit systems in orogenic belts on a global scale.

Driving forces and their relative contributions to hydrocarbon expulsion from deep source rocks: A case of the Cambrian source rocks in the Tarim Basin

To thoroughly understand the dynamic mechanism of hydrocarbon expulsion from deep source rocks, in this study, five types of hydrocarbon expulsion dynamics (thermal expansion, hydrocarbon diffusion, compaction, product volume expansion, and capillary pressure difference (CPD)) are studied. A model is proposed herein to evaluate the relative contribution of different dynamics for hydrocarbon expulsion using the principle of mass balance, and the model has been applied to the Cambrian source rocks in the Tarim Basin. The evaluation results show that during hydrocarbon expulsion from the source rocks, the relative contribution of CPD is the largest (>50%), followed by compaction (10%–40%), product volume expansion (5%–30%), and thermal expansion (2%–20%). The relative contribution of diffusion to hydrocarbon expulsion is minimal (<10%). These results demonstrate that CPD plays an important role in the hydrocarbon expulsion process of deep source rocks. The hydrocarbon expulsion process of source rocks can be categorized into three stages based on the contribution of different dynamics to the process: the first stage is dominated by compaction and diffusion to expel hydrocarbons, the second stage is dominated by product volume expansion and CPD, and the third stage is dominated by product volume expansion and CPD. This research offers new insights into hydrocarbon exploration in tight oil and gas reservoirs.

Quantifying the Seismicity Parameters of A New Model of Seismic Source Zone for Aceh and Surrounding Areas

Aceh is justified as one of the Indonesian provinces with a high level of seismicity. This high seismicity certainly has a severe negative impact on various aspects of human life in Aceh and the surrounding areas. Various types of efforts must be carried out to solve and mitigate the problem caused by each earthquake in Aceh and the surrounding areas. One aspect that can be carried out to minimize the hazards of seismic activity is the characterization of the source of the earthquake. This characterization can be used for various purposes for further seismic-related studies, including for studying seismic hazard analysis using the probabilistic seismic hazard analysis (PSHA) method. This research aims to determine the characteristics of the seismic source zones for Aceh and the surrounding areas. Based on the geological setting and seismicity catalog data of Aceh and the surrounding areas, a new model of seismic source zones was developed. This new model proposed for Aceh and the surrounding areas is divided into four zones: shallow background seismic source zones (divided into two source zones), two deep background seismic source zones, two megathrust source zones, and one fault zone, namely the Sumatra fault zone. The results of this study suggest that Zone I and Zone II of shallow background seismic source zones have a-values of 2.36 and 4.7, b-values of 0.545, and Mmax of 7.7 and 6.8. Deep background seismic source zone I has an a-value of 4.43 and a b-value of 0.9 with a maximum magnitude of 7 Mw. Meanwhile, deep background seismic source zone II has an a-value of 3.28 and a b-value of 0.755 with a maximum magnitude of 6.1 Mw. Megathrust seismic source zone I has an a-value of 3.53 and a b-value of 0.691 with a Mmax of 7.7 Mw. Meanwhile, the megathrust seismic source zone II has an a-value of 3.81 and a b-value of 0.702 with a Mmax of 7.1 Mw. Sumatra fault seismic source zone has an a-value of 2.88 and a b-value of 0.615 with a Mmax of 6.7 Mw.

Middle Miocene forearc alkaline magmatism in Amami-Oshima Island, central Ryukyu Arc: implications for paleoreconstruction of Shikoku Basin

During the middle Miocene, forearc alkaline magmatism occurred in the Outer Zone of Southwest Japan and the northern Ryukyu Arc, resulting in the formation of forearc alkaline basaltic rocks with ocean island basalt (OIB)-like chemical signatures. In contrast, subduction-related magmatism was present in the central Ryukyu Arc. However, the southwestern margin of the forearc alkaline magmatism was poorly constrained in the Ryukyu Arc. We examined two basaltic dikes in the Chichibu accretionary complex of Amami-Oshima Island, the central Ryukyu Arc. The dikes cut massive basalt, reddish chert, varicolored shale, and grey chert. The chemical compositions of basaltic dikes are characterized by the enrichment of incompatible trace elements, possibly representing a low degree of partial melting from a deep mantle source. 40Ar/39Ar dating analyses indicate that the basaltic dikes yield ages of 16.37 ± 0.14 Ma and 16.51 ± 0.10 Ma. The paleomagnetic analyses on stepwise thermal demagnetizations allowed extracting the direction of stable magnetizations with unblocking temperatures of 450–575 °C for the two dikes [(Dec, Inc) = (138.1°, − 13.3°), (124.0°, − 24.9°)]. The magnetization could be primary, acquired either as part of a secular variation or a geomagnetic excursion during reversed polarity chron/subchron. The 40Ar/39Ar ages and paleomagnetic directions within the error range imply that they intruded almost simultaneously during C5Cn.2r (16.532–16.434 Ma). The age and trace element patterns of the basaltic dikes are comparable to those of Miocene alkaline basaltic rocks, which resulted from forearc alkaline magmatism during the initial subduction of the young and warm Shikoku Basin. The discovery of alkaline basaltic dikes on Amami-Oshima Island suggests that the distribution of middle Miocene forearc alkaline magmatism may extend to the central Ryukyu Arc. Hence, the northern end of the Kyushu-Palau Ridge (i.e., southern end of Shikoku Basin) could have been located south of Amami-Oshima Island around 16.5–16.4 Ma, then moved eastward to the current location.Graphical

Plate tectonics in action in the Mesoarchean: Implication from the Olondo greenstone belt on the Aldan Shield of Siberian Craton

The Archean Olondo greenstone belt (OGB) is located on the Aldan shield, the largest basement of the Siberia craton. With well-preserved abundant mafic-ultramafic rocks, ≥30% in volume, the OGB is unique among other greenstone belts in the world. In this study, we present the most up-to-date geochemical and isotopic data for the ultramafic-mafic rocks of the OGB, in order to better constrain their mantle sources and the plate tectonic process involved in the formation of OGB at ca. 3 Ga. The ultramafic rocks vary from fresh to serpentinized dunites, and are highly refractory as residual mantle phase as indicated by depletion in P-Platinum Group Elements (PGE) relative to I-PGEs for highly siderophile elements (HSE). Fresh dunites show U-shaped rare earth element (REE) patterns, with positive to negative Nb anomalies, indicative of late metasomatism in their mantle source. Rhenium-Osmium isotopic compositions of these dunites yield mantle model age (TMA) of 2960–3020 Ma, comparable to the formation age of the OGB at ca. 3 Ga. Together, the data suggest that, unlike mantle cumulate origin for most of the Archean ultramafic rocks, the OGB dunites were mantle residuals after a high degree of partial melting (>30%), which subsequently interacted with the subduction-related melt/fluid. On the other hand, the OGB mafic rocks including komatiitic and tholeiitic basalts show geochemical characteristics relative to the ultramafic residuals that reinforce a subduction-related regime as their formation setting, despite extra mid-ocean ridge and plume settings. Tholeiitic basalts yield variable REE patterns from depleted, chondritic, to enriched light rare earth elements (LREE) patterns, with variable Nb-Ta anomalies, indicating their similarities with modern N-MORB and boninites, comparable to mafic rocks in typical supra-subduction zone (SSZ) ophiolites. Such mafic rocks with combined lower εNd(t) and negative Nb-Ta anomalies were most likely the result of mixing with subducted components, consistent with the observed Nb depletion in the residual dunites. The Al-depleted komatiitic basalts may have originated from deep mantle source, corresponding to garnet stability field, confirmed by their depletion in HREE and requiring a mantle plume to transport and melt at such a depth. The OGB ultramafic-mafic rocks could be a record to witness plume-induced subduction initiation processes such that mantle plume, sea-floor spreading and subduction were all in operation in the Mesoarchean time.

Deep heat source detection using the magnetotelluric method and geothermal assessment of the Farafra Oasis, Western Desert, Egypt

Nonrenewable hydrocarbon energy sources provide the bulk of Egypt's energy. However, the nation needs to diversify its energy portfolio and use conventional and renewable energy in tandem to ensure its long-term economic growth; therefore, harvesting untapped geothermal resources might help Egypt meet its energy needs in a sustainable and effective manner. The Farafra Oasis is located in the midst of Egypt's Western Desert and has been selected as the focal point for sustainable long-term development in the Western Desert.Using a magnetotelluric (MT) survey, a deep exploration of the Farafra region has been conducted to explore the underlying geological state and, as a result, explain the origin of several thermal wells around the oasis. None of the prior studies reached the necessary depths to offer information on the surface of deep igneous rocks, which may be the source of heat in the study area. Two field excursions were conducted to measure 19 stations along a line crossing the Farafra Oasis and extending more than 130 km. The MT instrument measured periods greater than 1000 s to gather low-frequency data with great efficiency.On the basis of 2D inversion of MT data, a mathematical model of the Farafra region's geothermal system was built to visualize and characterize the heat sources underneath the Farafra Oasis. It was shown that the existence of a high-temperature pluton at considerable depth is the primary cause of the temperature rise in the aquifer under the Farafra Oasis, as the water mass builds up on top of plutonic rocks and flows upwards via fractures and faults.

Interconnection of magma sources beneath the Katmai volcanic system inferred from seismic tomography and petrology

The Katmai volcanic cluster in Alaska hosts eight volcanoes, most of which are presently active, including Novarupta, whose eruption in 1912 is considered as the largest in the World during the 20th and 21st centuries. We present a new seismic tomographic model for the upper crust beneath the Katmai Group calculated with the use of ∼173,000 arrival times of the P and S waves from ∼11,000 local earthquakes. The resulting distribution of the Vp/Vs ratio reveals a common deep magma source for the entire system below the depth of 5 km centered in the area of Katmai Pass. The tomographic model also demonstrates interconnections of this source with most of the active volcanoes of the group. Based on this model, we propose a possible mechanism for the Novarupta eruption in 1912. The high-Vp/Vs anomaly beneath Novarupta at depths below 5 km may represent a trace of intrusion of low-density volatile-rich rhyolite magma that was made additionally buoyant by vesiculation. This hypothesis is supported by our petrological analysis showing that amphibole is a stable phase in 1912 rhyolite, which require a deeper source than previously suggested. This ascent was accompanied by draining of denser andesite and dacite magmas from under Mount Katmai, which caused the Katmai edifice to collapse. A shallow anomaly of low Vp/Vs ratio right below Novarupta may trace the conduit filled with pumice-type highly porous rocks remained after the eruption.

Formation and implication of cold-seep carbonates in the southern South China Sea

Southern South China Sea (SCS), rich in oil and gas resources, can provide a favorable condition for the formation and development of cold seeps. However, the geochemical effect of cold seep activities and the carbon cycle in the SCS are not well understood. Cold-seep carbonates as a window to exploration of gas hydrate are of great significance to investigate the material circulation in cold-seep system and to reconstruct the paleo-climate environment in the SCS. In this research, eight cold-seep carbonates collected from the Beikang Basin, southern SCS, are generally presented as yellow-black irregular column, crust and block, and mainly composed of high magnesium calcite (HMC), indicating they probably formed inside the deep fluid migration pathway. The middle rare earth element (MREE) enrichment with no or positive Ce anomaly in the carbonates from BH-CL37A suggests that they precipitated in anoxic pore water, while heavy rare earth element (HREE) enrichment in BH-CL32A carbonate shows great effect of seawater and they were formed in shallower depth. Different enrichments of redox sensitive trace elements and (Mo/U) EF indicate the strong anoxic environment. It is concluded that the difference of fluid environment could affect the enrichment degree and precipitation rate of trace elements by the relations between trace elements and Al. Extremely depleted 13C, slightly enriched 18O and the variation of Sr isotopes have archived the main biogenic methane source and the co-effect of seawater and seep fluid driven from a deep source (possibly containing the water from hydrate dissociation). The unique and complex geological conditions in the southern SCS will lead to the distinct regional specificity of the cold seep, which is different from the cold seep system in the northern SCS. This study plays an essential role in fulfilling the understanding of the activities of cold seeps in the SCS, revealing the element migration and transformation in cold seeps and their influencing factors.

КАРИЙСКИЙ ЗОЛОТОРУДНЫЙ УЗЕЛ (ВОСТОЧНОЕ ЗАБАЙКАЛЬЕ): ГЕОХИМИЧЕСКИЕ ОСОБЕННОСТИ РУД, СВЯЗЬ МАГМАТИЗМА С ОРУДЕНЕНИЕМ

Dykes of the Amudzhikano-Sretenskiy complex (J3–K1) including hybrid porphyries are widely developed in the area of the Kara gold ore cluster. The parameters of the lanthanides distribution in them are close to those of ores of the quartz-tourmaline-pyrite association, indicating probable single sources of their formation. In hybrid porphyries, ΣTR is 52.24–123.35; in ores of the quartz-tourmaline-pyrite association ΣTR is 52.82–133.78. In hybrid porphyries, Eu/Sm is 0.18–0.65; in ores of the quartz-tourmaline-pyrite association Eu/Sm is 0.18–0.47. The degree of differentiation of magmatic chambers according to Eu/Eu* is 0.61-2.26 in dikes of hybrid porphyries; Eu/Eu* is 0.78–1.49 in ores of quartz-tourmaline-pyrite association. The represented data indicate that their magmatic chambers of dikes of hybrid porphyries and quartz-tourmaline-pyrite ores were not differentiated and, consequently, had a deep source. According to the geochemical composition, part of the Amudzhikano-Sretenskiy complex granite values corresponds to ore-bearing granites with goldmolybdenum mineralization. Ores of the actinolite-magnetite association are characterized by the highest gold contents among productive stages of gold mineralization. Close correlation relationships of Au with Zn, W, Mo were established in ores of the actinolite-magnetite association; in ores of the quartz-tourmaline-pyrite association – with Mo, Pb; in ores of the quartz-arsenopyrite association – with Pb, Mo, As, Ag.

Gas flares and modern degasation processes in the Arctic seas (on the frequency resonance results-based)

The newly obtained results of the frequency-resonance (FR) technologies application for the study of the sources and processes of seeps and pockmarks formation in the Arctic Region (Norwegian, Barents Sea) and the North Sea are considered. The experimental study of the seepage processes' source formation was carried out using modified methods of the FR-processing, and decoding of satellite images and photographs with the vertical scanning of the cross-sections. The study results of the methane seeps and pockmarks fields show that the intensity and dynamics of their formation partly depend on the inflow of gas fluids from deep sources because of active degassing processes. The use of FR-sounding technologies allows us to remotely determine the spatial regularities of zones of intense gas emission formation and the geological sources of migration probable depth. The study of seep and pockmark field results confirms the significant, but insufficiently taken into account, the influence of crust-mantle gas fluids on the nature and degassing processes features in the structures of the continental margins. New results confirm the crust-mantle gas fluids influence on the nature and degassing processes features in the scan points of Polar marginal structures. These data are important arguments in favor of the "volcanic model" of various structural elements formation in this Region. The FR- technologies data also showed a possibility of seeps and pockmarks use as shallow and deep hydrocarbon field indicators in gas emission areas. These independent data can be used in modeling the deep lithosphere structure and possible mechanisms of abiogenic hydrocarbon formation in Arctic margin structures. We suppose that hydrocarbons through deep channels migrate (from 57 km deep) to the upper crustal horizons where can form hydrocarbon fields. During this migration, gas seeps and pockmarks are formed on the sea bottom and part of the gas can migrate into the atmosphere. Modern degassing centers' studies have confirmed the presence of zones of active migration of gases into the atmosphere, which is an important influencing factor in the dynamics of global climate change processes on Earth. The experience of FR- technologies used in the fields of methane seeps and pockmarks study found in the structures of the Arctic Polar seas showed versatility and the possibility of their use in the study of large gas emissions in structures of different regions.

Deep Learning-Based Speech Specific Source Localization by Using Binaural and Monaural Microphone Arrays in Hearing Aids

A deep learning-based method is proposed for jointly detecting and localizing speech sources in a complex acoustic scene by using microphones of a hearing aid. Motivated by the human auditory system, peripheral preprocessing is applied on the microphone signals to obtain auditory subband signals that serve as input to the proposed deep neural network for detecting and localizing speech sources. In the proposed neural network, a combination of residual and dense aggregation learning is utilized rather than the conventional residual learning to preserve and reuse the spatial representations at the output layers. This process is performed to improve the gradient flow in deeper layers, in the training stage. The learning curves show that the proposed residual-dense aggregation mapping do improve the speed and accuracy of the convergence. The proposed model shows good performance in joint speech source detection and localization using a binaural microphone array (i.e., three channels at each side) but also using a monaural microphone array (i.e., four channels at the right side) despite of the short distances between the microphones. The proposed methods also outperform neural networks that are directly using STFT components of the binaural or monaural microphone arrays. In addition, the proposed models extended with learnable peripheral processing show slightly improved in detection and localization scores compared to the proposed models using the plain auditory subband signals, in both the binaural and monaural microphone arrays but only so, when the learnable peripheral processing is initialized with parameters stemming from human peripheral processing.

State-of-the-Art Analysis of Deep Learning-Based Monaural Speech Source Separation Techniques

The monaural speech source separation problem is an important application in the signal processing field. But recent interaction of deep learning algorithms with signal processing achieves remarkable performance improvement for speech source separation problems. This paper explores the numerous state-of-the-art deep learning-based monaural speech source separation algorithms in the time-frequency (T-F), time, and hybrid domains. The motivation, algorithm, and framework of different deep learning models for monaural speech source separation are analyzed. The benchmarked algorithms in the T-F domain can be categorized as deep neural networks (DNN), clustering, permutation, multi-task learning, computational auditory sense analysis (CASA), and phase reconstruction-based techniques, whereas the state-of-the-art time-domain approaches can be categorized as CNN, RNN, multi-scale fusion (MSF), and transformer-based techniques. The end-to-end post filter (E2EPF) is a hybrid algorithm combining T-F and time-domain works to achieve enhanced results. Time-domain models have shown improvement in separation performance compared to the T-F and hybrid domain models with small model sizes. Methods in T-F, time, and hybrid domains are compared using <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$SDR$ </tex-math></inline-formula> , <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$SI-SDR$ </tex-math></inline-formula> , <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$SI-SNR$ </tex-math></inline-formula> , PESQ, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$STOI$ </tex-math></inline-formula> as quality assessment metrics on some benchmark datasets.

Extreme Upwelling Events in the Seas of the Alor Kecil, Alor Island, Indonesia

Upwelling is a process by which deep, colder, higher-nutrient waters are brought to the sea surface. In the tropics, an indicator that an upwelling event has occurred is lowering of sea surface temperatures (SSTs) to 25°–27°C from a mean of ~28°C. Based on more than one year of in situ data, we observed an unusual extreme upwelling event (EUE) when the near-surface temperature (NST) dropped by 10°C within one hour during the spring tide in Mulut Kumbang Strait of Alor Kecil. The extreme minimum NST during this EUE was ~12°C, and the upward displacement speed of the cold water was ~0.012 m s–1. The increase in salinity from ~30‰ to 34‰–36 ‰ during the decrease in NST indicates a deep source for the cold water mass . From bathymetry and CTD data, the source of the cold water mass was a deep basin (&gt;300 m) located at the southern part of Pantar Strait. In this basin, the temperature at 270 m depth can be as low as 8°C. We suggest that tidal sloshing (i.e., the back-and-forth movement of water) brings the cold water mass through a channel that connects this deep basin to Mulut Kumbang Strait. Interactions between semi-diurnal (M2, S2, and N2) tidal components strongly modulate the tidal signal with a period of nearly one month. That EUEs only occur from August to November also suggests a strong monsoonal influence. Because tides are predictable, we suggest that future EUEs are predictable.

Фальсификаты рукописей Григория Распутина Новейшего времени и их распознавание

Never before has the handwritten legacy of Grigory Rasputin become the subject of scientific scrutiny. This gap is explained by the fact that Rasputin’s manuscripts has never been separated from the surviving corpus of his texts, which were published only partially and without appropriate textual preparation. Therefore, the author tried to compile a complete corpus of Rasputin’s manuscripts found in the archives and museums of Russia as well as from the rest of the world. This exercise enabled him to identify and record the main linguistic and archaeographic characteristics of Rasputin’s manuscript heritage. The process of compiling a corpora of manuscripts of an individual author and its subsequent critical examination naturally and inevitably leads to the isolation of a number of manuscripts from this corpus for reasons of their inconsistency with the characteristics found in the main body of manuscripts. The recent study of the corpus of Grigory Rasputin’s manuscripts revealed that a number of his newly discovered letters and notes turned out to be alien. It is evident that the accuracy of the conclusions drawn from the examination of written monuments directly depends on the expert’s familiarity with the reference samples in the original. But since the corpus of Rasputin’s manuscripts had not previously been formed, the examination was carried using reproductions, and without a deep source study or linguistic analysis of the manuscripts. This inevitably led to erroneous conclusions, in particular, to the recognition of secondary manuscripts as Rasputin’s originals. To confirm his theses, the author carries out a detailed examination of five manuscripts that have been identified in recent years and have been recognized by experts as originals. The main, but not the only argument with which the author tries to refute the conclusions of experts, is a linguistic analysis. The linguistic characteristics of Grigory Rasputin’s idiom provide us with the main criterion according to which one can reach a verdict on the authenticity of a particular manuscript authored by this historical figure.

STRATEGI PEMBELAJARAN DENGAN MENGGUNAKAN KONTEKSTUAL

Many factors influence the success of the learning process, including language learning. Student problems in learning language Arabic is students still need a long time to learn andimplement Arabic. Contextual learning model (contextual teaching and learning) is present in this era with the aim of helping students understand the meaning of teaching materials and relate them to the context of everyday life. The purpose of this study is to discuss in depth the theory of strategy contextual learning in learning Arabic. Deep data source. This research is a variety of literature books, journals, scientific papers, and also other documents both in physical and digital form are reviewed regarding contextual strategy. Data analysis techniques used in research this is a data analysis technique according to Matthew B. Miles and A. Michael Huberman which consists of 4 stages, namely data collection, data reduction, data display, and conclusion

Sequential melting of deep crustal source rocks in a rift system: An example from southern Tibet

Granitic rocks derived by sequential partial melting are not well-documented worldwide. This paper provides another new important case in southern Tibet. The Yardoi gneiss dome within the Southern Tibet Rift System (STRS) consists of at least four suites of Miocene high-Sr/Y granites, formed at 20.4 Ma, 18.9 Ma, 17.7 Ma, and 17.1 Ma, respectively. Geochemical data indicate that they are Na-rich and peraluminous granites with high Sr/Y and La/Yb ratios. These granites show relatively radiogenic 87Sr/86Sr(t) (0.7091–0.7149) and unradiogenic εNd(t) (−11.1 to −7.7) isotopic signatures. As crystallization ages become younger, they are characterized by decreases in εNd(t) and Sr/Y but increases in 87Sr/86Sr(t) and Rb/Sr. Such temporal trends could be explained by sequential partial melting of first the mafic lower crustal rocks and then progressively shallower metasedimentary rocks. These findings together with literature-derived data, suggest that from north to south along the STRS, as extension proceeded with a heat source from the upwelling of asthenospheric mantle, sequential partial melting produced different Miocene magmatic rocks. This provides new insight into the mechanisms for the generation of geochemical and isotopic variations in spatially confined but temporally progressed granitic rocks.