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Hill slope instability of Nainital City,Kumaun Lesser Himalaya,Uttarakhand,India

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Journal of Rock Mechanics and Geotechnical Engineering 2018年第2期10卷 280-289页

作者： Nirvan Sah Mohit Kumar Rajeev Upadhyay Som Dutt department of geology(CAS) Kumaun UniversityNainital263001India Wadia Institute of Himalayan geology 33 General Mahadeo Singh RoadDehradun248001India

Nainital City of Kumaun Lesser Himalaya is prone to mass wasting processes during monsoon season,which mischievously triggers the hill slope instability in this region. Slate, dolomitic limestone, silty sandstone and rhythmite of the Krol Formation are the main rock types. The present study focuses on the investigation of slope stability in the region in terms of potential seismicity and landslide. Geological and geotechnical mapping indicates that the major portion of the area is characterized by slope wash materials and buildings. The combination of 3-4 joint sets with one random joint is the main structure at *** major geological structures of this area are Nainital lake fault passing from the center of the lake, Main Boundary Thrust at SW, and Khuriya Fault passing from the SE direction of Nainital City. This work finds that different types of discontinuities(e.g. joints and faults), overburden due to unplanned civil structures,and neotectonic activity in the vicinity of this ara affect the stability of the city. The slate forms the base of the city, dipping slightly towards the lake side along the NW direction, thus accelerating the instability of this area. Rock mass rating(RMR), slope mass rating, factor of safety(FOS) and graphical analysis of the discontinuity for slope kinematics indicate that the study area is a landslide-prone zone. This study can facilitate reducing the risk of human life, and contribute to the ongoing construction works in the area.

关键词： Hill slope instability Himalaya region Wedge failure Rock mass rating(RMR) Factor of safety(FOS)

Syn-sedimentary tectonics and facies analysis in a rift setting: Cretaceous Dalmiapuram Formation, Cauvery Basin, SE India

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Journal of Palaeogeography 2018年第2期7卷 146-167页

作者： Nivedita Chakraborty Subir Sarkar department of geology Kabi Jagadram Roy Govt. General Degree College department of Geological Sciences Jadavpur University

The Cretaceous(Albian-Cenomanian) Dalmiapuram Formation is one of the economically significant constituents in the hydrocarbon-producing Cauvery rift basin, SE India that opened up during the Late Jurassic e Early Cretaceous Gondwanaland fragmentation. The fossil-rich Dalmiapuram Formation,exposed at Ariyalur within the Pondicherry sub-basin of Cauvery Basin, rests in most places directly on the Archean basement and locally on the Lower Cretaceous(Barremian-Aptian) Basal Siliciclastic Formation. In the Dalmiapuram Formation, a facies association of tectonically-disturbed phase is sandwiched between two drastically quieter phases. The early syn-rift facies association(FA 1), records the first carbonate marine transgression within the basin, comprising a bar-lagoon system with occasionally storms affecting along the shore and a sheet-like non-recurrent biomicritic limestone bed on the shallow shelf that laterally grades into pyrite e glauconite-bearing dark-colored shale in the deeper shelf. Spectacular breccias together with varied kinds of mass-flow products comprise the syn-rift facies association(FA 2). While the breccias occur at the basin margin area, the latter extend in the deeper inland sea. Clast composition of the coarse clastics includes large, even block-sized limestone fragments and small fragments of granite and sandstone from the *** beds of quieter intervals between tectonic pulses occur in alternation with them. Faulted basal contact of the formation, and small grabens filled by multiple mass-flow packages bear the clear signature of the syntectonic activity localized contortions, slump folds, and pillow beds associated with mega slump/slide planes and joints, which corroborates this contention further. This phase of tectonic intervention is followed by another relatively quieter phase and accommodates the late syn-rift facies association(FA 3). A tidal bar-interbar shelf depositional system allowed a transgressive systems tract motif to gr

关键词： Syn-sedimentary tectonics Facies analysis Carbonate shelf Cretaceous Dalmiapuram Formation Cauvery Basin

n-Alkane bound biomarker fingerprints from asphaltenes in the bitumens of Eastern Dahomey Basin,Nigeria:Source and genetic implications

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Petroleum Research 2024年第1期9卷 85-91页

作者： Modupe A.Egbeola Olubunmi C.Adeigbe Olajide J.Adamolekun department of geology University of IbadanIbadanNigeria structural geology and Tectonics Institute of Applied GeosciencesKIT-Karlsruhe Institute of TechnologyAdenauerring 20a76131KarlsruheGermany

The asphaltene fractions of the bitumens of Eastern Dahomey Basin in Nigeria,were analyzed by flash pyrolysis-gas chromatography(Py-GC)method in order to unravel its geochemical history and *** distributions of the initial biomarkers of the original oils from the pyrolysates are related to the assessment of organic matter source,paleo-redox conditions and source environment during ***,it effectively establishes the genetic relationship of the *** n-alkane distributions in the pyrolysates reveal nC_(9)-nC_(32)n-alkanes,maximizing at nC_(14),isoprenoids-pristane(Pr)and phytane(Ph),and some n-alkene *** peaks of low to medium-weight nC_(9)-nC20 n-alkanes and low peaks of nC_(21)+n-alkanes characterize the *** reveal that abundant algal organic matter with some terrigenous inputs contributed to the source rock of the *** high concentration of marine organic matter inputs to the source rock is further confirmed by the nC_(17)/nC27 ratios which range from 5.39 to 19.82 and shows the predominance of nC_(17)*** general unimodal n-alkane distributions in the bitumens indicate derivation from similar organic matter types showing that they are genetically *** anoxic to suboxic environmental conditions that prevailed during the deposition of the sediments is revealed by the isoprenoids,Pr/Ph ratios(0.72-1.28).Pristane/nC_(17)and Phytane/nC_(18)range from 0.16 to 0.33 and 0.22 to 0.56,revealing that the bitumens were from predominantly marine organic matter(type II kerogen)preserved in a reducing environment with no evidence of ***,the Ph/nC_(18)ratio and the cross plot of Pr+Ph/nC_(17)+nC_(18)allow the classification of the bitumens into two subfamilies/groups(A and B).The bitumen samples have low wax content as indicated by the degree of waxiness ranging from 0.21 to 0.38 which confirms low terrigenous *** on the carbon preference index(CPI:0.92 to 1.55)and odd-even predo

关键词： Genetic relationship Flash pyrolysis Biomarker Asphaltene Pyrolysates

Composition of Pancarli Magmatic Ni-Cu±(PGE) Sulfide Deposit in the Cadomian-Avalonian Belt, Eastern Turkey

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Journal of Earth Science 2020年第3期31卷 536-550页

作者： Esra Yildirim Nail Yildirim Cahit Donmez Kurtulus Gunay Taner Korkmaz Mustafa Akyildiz Burcu Goren Firat University Department of Geology EngineeringElazig 23119Turkey general Directorate of Mineral Research and Exploration of Turkey Department of Mineral Research and ExplorationAnkara 06520Turkey Cukurova University Department of Geology EngineeringAdanaTurkey

Pancarli Ni-Cu±(PGE)sulfide deposit occurs in the Neoproterozoic basement complex of the Bitlis massif,which is one of the Andean-type active continental margin fragments with arc-type assemblages represented by the Cadomian orogenic *** sulfides are associated with quartzo-feldspathic gneisses(country rock)and mafic intrusions(host rock).Composed of only semi-massive ore,the Ni-Cu±(PGE)sulfide deposit is a small-scale deposit,and it does not contain net-textured and disseminated *** mineral assemblage comprises pyrrhotite,pentlandite,and *** semi-massive ore samples contain 2.2 wt.%-2.9 wt.%Ni,0.8 wt.%-2.2 wt.%Cu(Cu/(Cu+Ni)=0.2-0.5)and 0.13 wt.%-0.17 wt.%*** Cu/Ni ratios(average 0.57)are consistent with the segregation of sulfides from a basaltic *** Pt+Pd100%S values of 0.08 ppm-0.89 ppm,relatively low Pt/Pd ratios of 0.2-1.4,and Pd/Ir ratios of 4.5-39 have also been *** values demonstrate that the magma reached S saturation before its emplacement and the mineralization with high Cu/Pd ratios formed by sulfides segregated from a PGE-depleted magma.δ^34S isotope values(average-3.1‰)of Pancarli sulfides are lower than mantle ***δ^34S value indicates contamination from surrounding *** the composition,remobilization style and magma type,the Pancarli Ni-Cu±(PGE)sulfide deposit is similar to the deposits associated with Andean-type magmatic arcs located in the convergent plate margin settings.

关键词： Ni-Cu±(PGE)sulfide deposit δ^34S isotopes Neoproterozoic Andean type eastern Turkey

Geochemical characteristics of natural gases and source rocks in Obayied sub-basin,north Western Desert,Egypt:implications for gas-source correlation

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Acta Geochimica 2023年第2期42卷 241-255页

作者： Mostafa Hassan Mahmoud Leila Mohammed Ahmed Ghalib Issa Omar Hegab geology department Faculty of ScienceMansoura UniversityMansoura 35516Egypt Egyptian general Petroleum Corporation CairoEgypt

Western Desert represents a major oil and gas province in Egypt producing more than 50%of the country’s oil *** and gas blend occurs in most producing fields,however,the genetic link between gas and liquid hydrocarbon phases are not *** sub-basin in the Western Desert where oil and gas phases coexist in the Middle Jurassic sandstones of the Khatatba Formation provides an ideal place to investigate the link between oil and gas *** analyses on rock samples(Rock–Eval pyrolysis,vitrinite reflectance,R_(o))and gases(molecular and isotopic composition)were conducted in order to identify the genetic characteristics of the hydrocarbon phases ***-relevant parameters(Rock–Eval T_(max),vitrinite reflectance R_(o))elucidate that only Middle Jurassic Khatatba organofacies capable of generating wet and dry hydrocarbon ***,the enrichment of C_(7)normal alkanes,mono-branched alkanes relative to polybranched components in the Obayied gases reflect their generation via cracking of *** modelling results confirm gas generation through both primary and secondary ***,secondary cracking of liquid hydrocarbon phases is volumetrically more *** cracking of the Khatatba organofacies likely predate and catalyze the secondary cracking of the liquid phases and therefore the volume of generated gas increases incrementally eastward where both processes *** present study highlights the significant role of secondary cracking in the generation and accumulation of huge gas accumulations in the basins containing oil-prone source intervals.

关键词： Primary and secondary cracking Gas geochemistry Jurassic Khatatba Obayied Western Desert

Fluid Inclusion Studies and Geochemistry of Rare Earth Elements of Hydrothermal Fluorites from Pohrenk,Kirsehir,Central Turkey

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Acta Geologica Sinica(English Edition) 2001年第1期75卷 59-65页

作者： Sükrü KOC Ali RECBER geology department Ankara UniversityAnkara 06100Turkey general Directorate of Mineral Research and Exploration Ankara

Fluorite mineralization occurs along fractures and cracks of Middle Eocene and Pliocene limestones and marls in the north and northeast of the P?hrenk region (?i?ekdagi, Kirsehir). Tb/Ca – Tb/La and Y/Ho ratios were obtained from REE contents of fluorites which have revealed that mineralization is of hydrothermal type. Negative Ce anomalies and positive Eu anomalies reflect that hydrothermal solutions once had high oxygen fugacity. Fluid inclusion studies indicate that homogenization temperatures of mineralization varied between 90°C and 200°C, and hydrothermal solutions are composed of NaCl + KCl + MgCl2 + H2O. In addition, salinity measurements show that hydrothermal solutions were mixed with meteoric or rock formation water. Geologic setting, REE geochemistry and fluid inclusion studies suggest that mineralization was deposited from a solution generated by mixing of magmatic and meteoric water under epithermal conditions.

关键词： fluorite rare earth elements fluid inclusions

Macular microvascular and structural changes on optical coherence tomography angiography in atypical optic neuritis

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World Journal of Methodology 2025年第1期15卷 88-94页

作者： Chinmay Mahatme Madhurima Kaushik Veerappan Rathinasabapathy Saravanan Karthik Kumar Virna M Shah department of general Ophthalmology Aravind Eye HospitalCoimbatore 641014Tamil NāduIndia department of Neuro-ophthalmology Aravind Eye HospitalCoimbatore 641014Tamil NāduIndia department of Vitreoretina Aravind Eye HospitalCoimbatore 641014Tamil NāduIndia

BACKGROUND Atypical optic neuritis,consisting of neuromyelitis optica spectrum disorders(NMOSD)or myelin oligodendrocyte glycoprotein antibody disease(MOGAD),has a very similar presentation but different prognostic implications and longterm management *** and metabolic factors are being thought to play a role in such autoimmune neuro-inflammatory disorders,apart from the obvious immune mediated *** the advent of optical coherence tomography angiography(OCTA),it is easy to pick up on these subclinical macular microvascular and structural *** To study the macular microvascular and structural changes on OCTA in atypical optic *** This observational cross-sectional study involved 8 NMOSD and 17 MOGAD patients,diagnosed serologically,as well as 10 healthy *** vascular density(MVD)and ganglion cell+inner plexiform layer thickness(GCIPL)were studied using *** There was a significant reduction in MVD in NMOSD and MOGAD affected as well as unaffected eyes when compared with healthy *** and MOGAD affected eyes had significant GCIPL thinning compared with healthy *** unaffected eyes did not show significant GCIPL thinning compared to healthy controls in contrast to MOGAD unaffected *** comparing NMOSD with MOGAD,there was no significant difference in terms of MVD or GCIPL in the affected or unaffected *** Although significant microvascular and structural changes are present on OCTA between atypical optic neuritis and normal patients,they could not help in differentiating between NMOSD and MOGAD cases.

关键词： Optical coherence tomography angiography Atypical optic neuritis Macular microvascular changes Neuromyelitis optica spectrum disorders Myelin oligodendrocyte glycoprotein antibody disorder

Paleo and Modern Stress Regimes of Central North Tabriz Fault, Eastern Azerbaijan Province, NW Iran

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Journal of Earth Science 2015年第3期26卷 361-372页

作者： A Yousefi-Bavil M Moayyed department of Geotectonics and Regional geology Geology Institute of Azerbaijan department of Earth Sciences University of Tabriz

The North Tabriz fault is a segmented dextral fault in Northwest Iran, with a history of major destructive earthquakes that have repeatedly destroyed the city of Tabriz（current population 1.6 million）. The quiescence of the fault（last major temblor in 1854） and a lack of outcrop study have hampered stress analysis. Resolution of the stress states on the fault could be used for seismotectonic study along the North Tabriz fault and for understanding the geodynamics of the Arabia-Eurasia collision zone. Using fault-slip data collected from 88 localities in the fault system, we conducted an inversion analysis of this fault-slip data and analysis of the stratigraphic, geometric, and structural information. As a result, we confirmed that transcurrent deformation is prevalent on the North Tabriz fault and adjacent areas and is generally accomplished by predominant NW-SE-trending dextral and NE-SW-trending sinistral faults. Specifically, three separate tectonic episodes are recognised from the stress inversion data, consistent with the geologic data：（i） a post-Cretaceous and pre-Early Miocene compressional（Laramian） stress regime,（ii） an Early Miocene extensional stress regime, and（iii） modern tectonic episode with different local stress regimes（compressional and extensional） along the different segments of this fault.

关键词： stress regime NW Iran tectonics North Tabriz fault stress inversion strike-slip fault

Hydrogen-rich water protects against inflammatory bowel disease in mice by inhibiting endoplasmic reticulum stress and promoting heme oxygenase-1 expression

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World Journal of Gastroenterology 2017年第8期23卷 1375-1386页

作者： Nai-Ying Shen Jian-Bin Bi Jing-Yao Zhang Si-Min Zhang Jing-Xian Gu Kai Qu Chang Liu department of Hepatobiliary Surgery The First Affiliated Hospital of Xi’an Jiaotong University department of general Surgery Shaanxi Nuclear Geology 215 Hospital

AIM To investigate the therapeutic effect of hydrogen-rich water(HRW) on inflammatory bowel disease(IBD) and to explore the potential mechanisms *** Male mice were randomly divided into the following four groups: control group, in which the mice received equivalent volumes of normal saline(NS) intraperitoneally(ip); dextran sulfate sodium(DSS) group, in which the mice received NS ip(5 m L/kg body weight, twice per day at 8 am and 5 pm) for 7 consecutive days after IBD modeling; DSS + HRW group, in which the mice received HRW(in the same volume as the NS treatment) for 7 consecutive days after IBD modeling; and DSS + HRW + Zn PP group, in which the mice received HRW(in the same volume as the NS treatment) and ZnP P [a heme oxygenase-1(HO-1) inhibitor, 25 mg/kg] for 7 consecutive days after IBD modeling. IBD was induced by feeding DSS to the mice, and blood and colon tissues were collected on the 7th d after IBD modeling to determine clinical symptoms, colonic inflammation and the potential mechanisms *** The DSS + HRW group exhibited significantly attenuated weight loss and a lower extent of disease activity index compared with the DSS group on the 7th d(P < 0.05). HRW exerted protective effects against colon shortening and colonic wall thickening in contrast to the DSS group(P < 0.05). The histological study demonstrated milder inflammation in the DSS + HRW group, which was similar to normal inflammatory levels, and the macroscopic and microcosmic damage scores were lower in this group than in the DSS group(P < 0.05). The oxidative stress parameters, including MDA and MPO in the colon, were significantly decreased in the DSS + HRW group compared with the DSS group(P < 0.05). Simultaneously, the protective indicators, superoxide dismutase and glutathione, were markedly increased with the use of HRW. Inflammatory factors were assessed, and the results showed that the DSS + HRW group exhibited significantly reduced levels of TNF-α, IL-6 and IL

关键词： Hydrogen Inflammatory bowel disease Oxidative stress Endoplasmic reticulum stress Heme oxygenase-1