Journal of Asian Earth Sciences: X最新文献

{"title":"Shuttle radar topography-based analysis reveals the active Borneo Island Fault in Borneo, SE Asia","authors":"Hazwan Syafiq ,&nbsp;A.A. Shah ,&nbsp;Muhammad Gazali Rachman","doi":"10.1016/j.jaesx.2024.100184","DOIUrl":"10.1016/j.jaesx.2024.100184","url":null,"abstract":"<div><p>This study presents the results of shuttle radar topography-based analysis providing new insights into the geological and structural architecture of the island of Borneo. The aim is to examine whether Borneo is tectonically active and to better understand the origin of prominent topographic features such as the Dulit Plateau and the large oroclinal bend of Sarawak. The results show that the Tinjar and the Lupar lines are tectonically active fault zones. The Lupar fault zone is broadly distributed along the spine of the island, representing a major suture featured by ophiolites and extensive volcanism. The development of the Dulit Triangle and the large oroclinal bend are related to fault interactions. The seismological, geodetic and geomorphological evidence suggests that Borneo is tectonically active. The Borneo Island Fault is the major active fault piercing through the island’s mountainous backbone. On a tectonic scale, the oblique northeastward active convergence of the Australian plate with the Sunda plate drives the deformation on the island of Borneo, some of which is also associated with the northward motion of the Philippine Sea plate. Recent GPS data indicate that the Sunda plate is moving slowly to the southwest, and our results suggest this motion is consistent with the interaction between the Sunda and the Australian plates.</p></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"12 ","pages":"Article 100184"},"PeriodicalIF":1.7,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590056024000124/pdfft?md5=eee27b96b452e7def2e11cd31ffaf808&pid=1-s2.0-S2590056024000124-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142129114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quaternary deposition and erosion in the northeastern sunda strait: An interplay between sea level, tectonics, and magmatic activity","authors":"Susilohadi Susilohadi ,&nbsp;Franto Novico ,&nbsp;Laurent Husson ,&nbsp;Riza Rahardiawan ,&nbsp;Harkins Prabowo ,&nbsp;Joni Widodo ,&nbsp;Evie Hadrijantie Sudjono","doi":"10.1016/j.jaesx.2024.100179","DOIUrl":"10.1016/j.jaesx.2024.100179","url":null,"abstract":"<div><p>The northeastern Sunda Strait is a narrow strait separating Java and Sumatra islands. Currently, it forms a seaway between the Java Sea and the Indian Ocean. The geological setting of the region is extremely dynamic, but how the Plio-Pleistocene interplay between sea level oscillations, magmatism, and tectonics, which lead to the current setting, has not been completely understood. We analysed an important set of legacy shallow seismic data from this area to decipher these intricate relationships. Our results indicate that the tectonic extension partly dismantled the Indonesian arc since the Middle Miocene. However, volcanic products formed a barrier between the Sunda Shelf and the Indian Ocean during the Late Pliocene to the Middle Pleistocene. Marine flooding started during the Middle Pleistocene but bypassed the barrier by flooding the NW edge of Java Island. During the Late Pleistocene, high amplitudes and longer periods of the glacial-interglacial cycles ultimately connected the Java Sea with the Indian Ocean. Still, it was only during the Holocene that important erosion made this seaway efficient in transporting seawater between the two reservoirs.</p></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"12 ","pages":"Article 100179"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590056024000070/pdfft?md5=257ed79d4e73ea2544892ab385b47d9e&pid=1-s2.0-S2590056024000070-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141279927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anthropogenic impacts on the water chemistry of a transboundary river system in Southeast Asia","authors":"Duc A. Trinh ,&nbsp;Nga T. Do ,&nbsp;Virginia N. Panizzo ,&nbsp;Suzanne McGowan ,&nbsp;Jorge Salgado ,&nbsp;Andy R.G. Large ,&nbsp;Andrew C.G. Henderson ,&nbsp;Thuy T. Vu","doi":"10.1016/j.jaesx.2024.100183","DOIUrl":"10.1016/j.jaesx.2024.100183","url":null,"abstract":"<div><p>The Red River originating from Yunnan province, China is the second largest river in Vietnam in terms of length and discharge. Combination of water chemistry monitoring data of 4 years (2018–2022) from different sub-basins of the Red River (the Da, Lo, Thao, Tra Ly, and Day) with historical datasets indicates a decline in pH from 8.1 in 2000 to 7.7 in 2021, greater CO₂ concentrations and a shift from waters naturally dominated by carbonate weathering to waters dominated by evaporite weathering. Such changes were most apparent in the delta area where heavy human activities have increased influxes of most dissolved chemicals, except SiO₂. Evaporite weathering is particularly enhanced by mining and deforestation occurring in upstream regions of both China and Vietnam. Pyrite oxidation, alongside silicate weathering, is enhanced along the Red River Fault Zone but reduced in tributaries with a higher proportion of hydropower reservoirs. Longer water residence times in these large reservoirs (total volume &gt; 2.7x10¹⁰ m³) located in the Da and Lo sub-basins have also increased primary productivity, leading to higher evasion/uptake of CO₂ and SiO₂, lower total dissolved solids (TDS), and higher pH. The total physical and chemical denudation rates of upstream mountain tributaries ranged between 0.107 ± 0.108 and 0.139 ± 0.137 mm yr⁻¹, mainly due to reservoir implementation and instream aquatic biogeochemistry changes. Our findings demonstrate that anthropogenic activities are profound factors impacting the water chemistry of the Red River system.</p></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"12 ","pages":"Article 100183"},"PeriodicalIF":1.7,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590056024000112/pdfft?md5=89ed199b16d1c7b2a79f98be11fbb1d7&pid=1-s2.0-S2590056024000112-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141998356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Petrography and stratigraphic Os isotopic ages of ferromanganese nodules from the Northwest Pacific east of Minamitorishima Island","authors":"Tatsuo Nozaki ,&nbsp;Kosuke T. Goto ,&nbsp;Yutaro Takaya ,&nbsp;Kazuhiko Shimada ,&nbsp;Akira Owada ,&nbsp;Gen Shimoda ,&nbsp;Jun-Ichi Kimura ,&nbsp;Qing Chang ,&nbsp;Tetsuji Onoue ,&nbsp;Shiki Machida ,&nbsp;Teruaki Ishii ,&nbsp;Kenji Shimizu ,&nbsp;Naoto Hirano ,&nbsp;Kazuhide Mimura ,&nbsp;Moei Yano ,&nbsp;Junichiro Ohta ,&nbsp;Yasuhiro Kato","doi":"10.1016/j.jaesx.2024.100176","DOIUrl":"https://doi.org/10.1016/j.jaesx.2024.100176","url":null,"abstract":"<div><p>The area offshore of Minamitorishima Island, Northwestern Pacific Ocean, contains large amounts of seafloor mineral resources such as ferromanganese (Fe–Mn) nodules, Fe–Mn crusts, and rare-earth element and yttrium (REY)-rich muds. In this study, we applied stratigraphic Os isotopic dating to a Fe–Mn nodule for the first time to date its formation/depositional age, and mineralogical and texturally characterized a complementary nodule. Based on macroscopic and microscopic observations, the studied Fe–Mn nodules can be divided into three layers: Layers L2, L1, and L0 from core to rim. Under the microscope, the Fe–Mn nodules are dominated by vernadite and Fe-oxyhydroxide. In particular, Layer L1 is dominated by banded-columnar vernadite and contains lower amounts of clay minerals derived from the detrital component than Layers L2 and L0. The bulk major and trace element geochemical compositions of sampled layers in the Fe–Mn nodules all plotted in the hydrogenous field in several discrimination diagrams. The Os isotopic ages determined by fitting to the paleo-seawater ¹⁸⁷Os/¹⁸⁸Os curve can be divided into three clusters (35.7–31.0, 19.0–9.0, and 4.0–1.0 Ma, corresponding to Layers L2, L1, and L0, respectively). These Os isotopic ages indicate that two periods of very slow growth or growth hiatuses occurred during the formation of the Fe–Mn nodule; these age gaps are related to the intermittent (discontinuous) timings of the beginning of Fe–Mn nodule formation offshore Minamitorishima Island.</p></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"11 ","pages":"Article 100176"},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590056024000045/pdfft?md5=b5858134166c3bde55b62c0495a4faf1&pid=1-s2.0-S2590056024000045-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140163873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Provenance of the lower Cretaceous Lumshiwal Formation, Surghar Range, northwestern Indian Plate, Pakistan: Insights from new petrographical and geochemical analysis","authors":"Muhammad Waseem Khan ,&nbsp;Saif Ur Rehman ,&nbsp;Sajjad Ahmed ,&nbsp;Shahid Jameel Sameeni","doi":"10.1016/j.jaesx.2023.100172","DOIUrl":"https://doi.org/10.1016/j.jaesx.2023.100172","url":null,"abstract":"<div><p>This paper documents the provenance and palaeoclimatic conditions of the Cretaceous Lumshiwal Formation near the western margin of the Indian plate in the Surghar Range, northwest Pakistan. The combined techniques of petrography, X-ray diffraction (XRD), and bulk rock geochemistry were utilized to reveal the source and mineral-geochemical composition and sandstone type. The petrographic analysis of the sandstones confirms the dominance of quartz, feldspar, and rock fragments, with subordinate occurrences of muscovite, magnetite, and hematite. Heavy minerals consist of tourmaline, titanite (sphene), rutile, cassiterite, monazite, and zircon. The cementing material includes ferruginous clays, jarosite, glauconite, calcite, minor dolomite, gypsum, and silica. The modal composition plot of the sandstones falls into arkose to sub-arkose, with a few lithic arkose varieties. Lithic fragments mainly include granite, with a minor occurrence of granitic gneiss, chert, phyllite, and quartz mica schist. The discriminatory provenance diagram of the sandstones suggests a transitional continental provenance. The bulk rock geochemistry of the sandstones reveals the presence of SiO₂, TiO₂, Al₂O₃, Fe₂O₃, FeO, MnO, CaO, MgO, Na₂O, K₂O and P₂O₅. The petrographical mineral findings were corroborated with XRD, SEM, and bulk rock geochemistry analysis (major element concentrations and their ratios), which collectively all confirm a felsic igneous source. The tectonic discrimination diagram (SiO₂-log K₂O/Na₂O wt %) implies a dominant influx of sediment sourced from the passive continental margin of the uplifted Gondwana Indian plate. Terrigenous sediments found in the Lumshiwal Formation are interpreted to have been derived from granites and granitic gneisses of the Indian Shield. The palaeo-weathering index, including the chemical index of alteration (CIA) and the chemical index of weathering (CIW) of the Lumshiwal Formation confirms a low to moderately weathered source area. The climate discrimination plot (SiO₂ versus Al₂O₃ + Na₂O + K₂O) shows that humid to semi-humid climatic conditions during the deposition of the Lumshiwal Formation.</p></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"11 ","pages":"Article 100172"},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590056023000373/pdfft?md5=d329e257640ce251741dcf4c0d2d633f&pid=1-s2.0-S2590056023000373-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139100047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mineral chemistry and alteration patterns of Cr-spinel in serpentinized peridotites from NW Iran","authors":"Mohssen Moazzen ,&nbsp;Masoumeh Ahangari ,&nbsp;Roland Oberhänsli ,&nbsp;Uwe Altenberger","doi":"10.1016/j.jaesx.2024.100178","DOIUrl":"https://doi.org/10.1016/j.jaesx.2024.100178","url":null,"abstract":"<div><p>The Late Cretaceous ophiolite mélange in the Salmas area of NW Iran is a part of the Neotethys ophiolites. The mélange includes serpentinized harzburgite, serpentinites, mafic rocks, radiolarite, layered red pelagic limestones and grey and white marbles. Harzburgite main primary mineral phases are olivine, orthopyroxene, clinopyroxene and Cr-spinel. Cr-spinel has Cr₂O₃ contents of 21.13 to 30.18 wt% and high Al₂O₃ (38.67–48.52 wt%), FeO (15.18–18.13 wt%) and MgO (15.18–17.51 wt%) contents. The 100 × Cr/(Cr + Al) ratios of 23 to 34 indicate 9 to 13 % partial melting in the Mid Ocean Ridge (MOR) environment for the origin of the peridotites. An alteration zone is developed around the altered Cr-spinel. Fine-grained minerals assemblage at the spinel crystals’ margin includes Cr-rich chlorite, Cr-rich garnet and spinel-silicate mixture. A 2–5 μm wide transitional zone is developed between the chromite-silicate assemblage and the Cr-rich garnet zone. The chemical variations of major oxides across the alteration zone are mainly diffusion controlled. Al, Cr and Mg have diffused out from the primary spinel and Fe and Mn have diffused into the spinel. Cr-spinel is altered in two stages due to serpentinization. During the first stage and following hydration, spinel reacted with olivine and orthopyroxene to form Cr-rich chlorite and ferrian chromite. Silica formed at this stage. At the second stage, the reaction between the chromite-silicate assemblage and Cr-rich chlorite plus silica form the first stage and Ca²⁺ in the fluid (released from clinopyroxene alteration) produced Cr-rich garnet and H₂O-rich fluid, at temperature between 400 and 600 °C.</p></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"11 ","pages":"Article 100178"},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590056024000069/pdfft?md5=e44776860847660f40be2143972ae8ce&pid=1-s2.0-S2590056024000069-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140338578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Source rock potential, thermal maturity, and depositional environment of the Ordovician Ra’an Shale Member, central Saudi Arabia","authors":"Faisal AlGhamdi ,&nbsp;Lamidi Babalola ,&nbsp;Abdullah Alqubalee ,&nbsp;Israa S. Abu-Mahfouz ,&nbsp;Bandar Alotaibi ,&nbsp;Mohammed Abouelresh","doi":"10.1016/j.jaesx.2024.100174","DOIUrl":"https://doi.org/10.1016/j.jaesx.2024.100174","url":null,"abstract":"<div><p>The Ordovician Ra’an Shale Member of the Qassim Formation in Saudi Arabia has potential as an unconventional hydrocarbon play. This shale unit, however, has not been studied in detail for its geochemical characteristics, thermal maturity, and reservoir quality. This study aims to investigate this shale member from a well-exposed section at Khashm Ra’an in the Qassim region, central Saudi Arabia. Detailed fieldwork followed by comprehensive geochemical and petrographic analyses were conducted to evaluate the hydrocarbon potential and interpret the depositional setting of this shale member. Integration of field sedimentological description, sample description and thin section petrography facilitated the identification of partially burrowed laminated fish-bearing shale, bioturbated siltstone, graptolite-bearing shale, shale/siltstone and sandstone/shale interbeds in the investigated outcrop. The intervals were sandwiched between the bioturbated sandstone of the underlying Kahfah Sandstone and the overlying Quwarah Formation. These lithofacies are interpreted to have been deposited in a shallow marine depositional setting. The preservation of graptolite in some intervals indicates low bottom dissolved oxygen conditions. The mineralogical analysis indicated that clay minerals, quartz, and feldspars are the major mineralogical components in the study samples. Based on mineralogical compositions, the studied samples were classified into three main lithofacies types; silica-rich argillaceous mudstone, clay-rich siliceous mudstone, and mixed siliceous mudstone lithofacies. Elemental analysis proxies indicated that most of the tested samples were deposited in anoxic environment. The calculated values of the chemical index of weathering (CIW) indicated that samples were exposed to high rates of weathering, which negatively impacted organic matter preservation.</p><p>Microscopic investigation identified the pore systems of the Ra’an Member as interparticle, interparticle and fracture pore systems, and observed the diagenetic features in the form of cementation, compaction, and dissolution. Organic geochemical analysis indicates that the samples are mainly of kerogen type III and II/III with poor to fair potential for hydrocarbon generation. This study provides an improved understanding of the depositional setting, organic geochemical, and thermal evolution of the Ra'an Member as a potential unconventional hydrocarbon reservoir.</p></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"11 ","pages":"Article 100174"},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590056024000021/pdfft?md5=911f2a55b2dc0653d2cd8d30f293253b&pid=1-s2.0-S2590056024000021-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139652929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of earthquake potential using a kinematic crustal block motion model in Java, Indonesia, based on GNSS observation","authors":"Rio Raharja ,&nbsp;Takeo Ito ,&nbsp;Irwan Meilano","doi":"10.1016/j.jaesx.2023.100171","DOIUrl":"10.1016/j.jaesx.2023.100171","url":null,"abstract":"<div><p>Assessing the earthquake potential in Java Island is of paramount importance due to its status as one of the world's most seismically active regions, a concern that is heightened by the island’s high population density. This study presents a comprehensive analysis of crustal deformation in Java Island, utilizing observations from Global Navigation Satellite System (GNSS) gathered over a decade, from 2008 to 2018. The GNSS data revealed a distinct non-linear trend, primarily due to the persistent post-seismic deformation following the 2006 M_w7.7 Java earthquake. To enhance the accuracy of our analysis, we employed viscoelastic relaxation modeling for data correction. Among the eleven unique crustal block motion models created, MODEL04 emerged as the optimal model for assessing earthquake potential. The seismic moment deficit rates obtained from this model provide valuable insight into the region's potential to generate future seismic events. Notably, our findings suggest that the convergence of the Australian plate with Western and Eastern Java carries the potential to produce earthquakes of M_w8.7 and M_w &gt; 7.8, respectively. An exploration of the inland fault interfaces revealed seismic moment deficit rates suggestive of the potential for M_w7.0 earthquakes.</p></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"11 ","pages":"Article 100171"},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590056023000361/pdfft?md5=783607521e3fe9ad02e726b9acef5f02&pid=1-s2.0-S2590056023000361-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138987215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shallow-water carbonate facies herald the onset of the Palaeocene-Eocene Thermal Maximum (Hazara basin, Northern Pakistan)","authors":"Mubashir Ali ,&nbsp;Giovanni Coletti ,&nbsp;Luca Mariani ,&nbsp;Andrea Benedetti ,&nbsp;Muhammad-Jawad Munawar ,&nbsp;Saif Ur Rehman ,&nbsp;Pietro Sternai ,&nbsp;Daniela Basso ,&nbsp;Elisa Malinverno ,&nbsp;Khurram Shahzad ,&nbsp;Suleman Khan ,&nbsp;Muhammad Awais ,&nbsp;Muhammad Usman ,&nbsp;Sébastien Castelltort ,&nbsp;Thierry Adatte ,&nbsp;Eduardo Garzanti","doi":"10.1016/j.jaesx.2023.100169","DOIUrl":"10.1016/j.jaesx.2023.100169","url":null,"abstract":"<div><p>We investigate the Palaeocene succession of the Hazara Basin (Northern Pakistan) to better understand the impact of climate change on marine carbonate-producing organisms. These shallow-water carbonates, deposited during the Late Palaeocene, before the onset of the Palaeocene-Eocene Thermal Maximum, were studied using a quantitative approach to highlight changes in the skeletal assemblage. We recognise a decrease in the abundance of colonial corals and green calcareous algae and an increase in larger benthic foraminifera and red calcareous algae from the early Thanetian to the late Thanetian. Increasing temperatures may represent a plausible cause for the decline of the more sensitive colonial corals in favor of the more tolerant larger benthic foraminifera. A similar pattern is observed in most successions deposited along the margins of the Neotethys Ocean, suggesting a connection with the Late Palaeocene environmental changes that heralded the PETM hyperthermal event. Our stratigraphic analysis of the Hazara Basin strata suggests that the biotic turnovers occurred during the Palaeocene – Eocene transition started already before the onset of the Palaeocene Eocene Thermal Maximum as recorded by the geochemical proxies.</p></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"11 ","pages":"Article 100169"},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590056023000348/pdfft?md5=f7fb86d5f0e52d4f3fc0ae1f8f7467c9&pid=1-s2.0-S2590056023000348-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138622125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An enhancement in the petrophysical evaluation in a vuggy carbonate gas reservoir by integrating the core data and empirical methods, Zagros basin, south of Iran","authors":"Seyed Javad Safavi ,&nbsp;Ramin Maldar","doi":"10.1016/j.jaesx.2024.100177","DOIUrl":"https://doi.org/10.1016/j.jaesx.2024.100177","url":null,"abstract":"<div><p>The presence of vuggy pore types poses challenges in accurately assessing effective porosity. This study focuses on the significant scientific issue of improving petrophysical evaluation in vuggy carbonate gas reservoirs. The Kangan Formation is one of the main gas reservoir formations in the southern Zagros region, Iran. The main objective of the current research is to distinguish and exclude the influence of vuggy pore types from effective porosity in the reservoir pay zones of the Kangan reservoir.</p><p>In the current research, a combination of full suite logs, image logs, core analysis, and thin section studies was employed. The image logs illustrate that vuggy porosity is abundant in the Kangan Formation and these results are confirmed by the available core thin sections, specifically in Zone Kangan_B; Additionally, the cross plots of compressional velocity versus bulk density and total porosity, as a part of rock physics study, indicate the characteristics of the vuggy reservoir. Two methods are utilized to quantify vuggy porosity. The first method, the Velocity Deviation Log (VDL) approach, identifies various available pore types, especially vugs. The second method is a newly proposed approach that can exclude vuggy porosity from the computed effective porosity. In this novel approach, a variable porosity exponent (m) is derived by adopting the Lucia equation to exclude vuggy porosity from the effective porosity computations. Thus, petrophysical evaluation can be implemented based on the constant and variable “m”. Comparing both petrophysical results, it is evident that the amounts of effective porosity and water saturation are modified in the vuggy-bearing intervals. Applying the proposed approach will improve the accuracy of petrophysical properties and lead to the proper calculation of the hydrocarbon volume in the carbonate reservoir rocks containing isolated vugs, particularly in gas-bearing reservoirs where conventional logs are affected by gas contents.</p></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"11 ","pages":"Article 100177"},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590056024000057/pdfft?md5=8e9e40aee0e4b36bc1eb610c2d94d3d7&pid=1-s2.0-S2590056024000057-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140332972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}