evaluation of relative tectonic perturbations of the kashmir basin northwest himalaya india an integrated morphological approach abstract geomorphic and morphotectonic evaluations of the kashmir basin have been carried by implicating different geomorphic indices such as stream gradient index sl hypsometric integral hi drainage basin asymmetry af valley floor height and width ratio vf transverse topographic symmetry factor t mountain front sinuosity smf drainage basin shape bs and sinuosity index si for the categorization of relative index of active tectonics riat through the use of geographic information systems gis so as to decipher the role of neotectonics in geomorphologic evolution of the basin the verified riat classes through field investigation and validation reveal the traverse of twenty one active faults in the basin with demarcation of three riat classes viz class 1 inactive 20 07 of the area class 2 moderately active 36 52 of the area and class 3 very active 43 4 of the area the observed values of riat distribution pattern are well corroborated with field observations ultimately the overall geomorphic outputs and clustering of recent seismicity support the active tectonic control over the kashmir basin india

early diagenesis of terrigenous triterpenoids and its implications for petroleum geochemistry abstract the distribution of triterpanes in sediments and crude oils is commonly used for oil oil and oil source rock correlation in petroleum geochemistry while isomer ratios of such compounds are applied as maturity parameters the triterpane pattern in terrestrially influenced geological samples is however remarkably less diverse than the triterpenoid skeletons occurring in the extant higher plant biosphere natural observations laboratory experiments and molecular mechanics calculations have revealed that acid catalysed double bond isomerization and skeletal rearrangement reactions of terrigenous triterpenoids during early diagenesis are the key to understanding the triterpane patterns in more matured geological materials examples studied in detail are the double bond isomerization of oleanenes and the subsequent hydrogenation of the products into oleanane and 18 oleanane and the transformation of taraxer 14 ene and lup 20 29 ene into oleanenes although the reactions are likely to be kinetically controlled the main products formed and ultimately preserved are the thermodynamically most stable ones the experimental results and natural observations have significant implications for the use of terrigenous triterpenoid compounds in petroleum geochemistry

novel tricyclic and tetracyclic terpanes in tertiary deltaic oils structural identification origin and application to petroleum correlation abstract tricyclic terpanes of the cheilanthane series in crude oils and sediments are routinely used for geochemical correlation the cheilanthanes are particularly useful to identify crude oils derived from marine clastic or carbonate source rock as well as input to the source rocks from marine algal or terrigenous organic matter however they sometimes have limitations for the correlation of oils expelled from different source rocks that received similar organic matter e g oils from source rocks dominated by terrigenous organic matter novel non cheilanthane tricyclic terpanes consisting of c21 and c25 compounds and a c27 tetracyclic terpane were identified in oils from the assam india beaufort mackenzie canada and the niger nigeria deltas nmr data reveal that all three compounds have an oleanane type structure with rings c d and e intact while rings a and b have been degraded leaving a side chain attached to ring c in the case of the tricyclics and only a degraded a ring in the tetracyclic on the basis of occurrence nmr structure and co variance with oleanane abundance these new tricyclic and tetracyclic compounds are believed to form from a ring functionalised oleanoid precursors in angiosperm flowering plants the distribution of these compounds in representative oils from the niger delta accumulations permits separation of the oils into at least three distinct source rock organofacies

mineralogy geochemistry and the origin of high phosphorus oolitic iron ores of aswan egypt abstract the coniacian santonian high phosphorus oolitic iron ore at aswan area is one of the major iron ore deposits in egypt however there are no reports on its geochemistry which includes trace and rare earth elements evaluation texture mineralogy and origin of phosphorus that represents the main impurity in these ore deposits have not been discussed in previous studies in this investigation iron ores from three localities were subjected to petrographic mineralogical and geochemical analyses the aswan oolitic iron ores consist of uniform size ooids with snowball like texture and tangentially arranged laminae of hematite and chamosite the ores also possess detrital quartz apatite and fine grained ferruginous chamosite groundmass in addition to fe 2 o 3 the studied iron ores show relatively high contents of sio 2 and al 2 o 3 due to the abundance of quartz and chamosite p 2 o 5 ranges from 0 3 to 3 4 wt showing strong positive correlation with cao and suggesting the occurrence of p mainly as apatite x ray diffraction analysis confirmed the occurrence of this apatite as hydroxyapatite under the optical microscope and scanning electron microscope hydroxyapatite occurred as massive and structureless grains of undefined outlines and variable size 5 150 m inside the ooids and or in the ferruginous groundmass among trace elements v ba sr co zr y ni zn and cu occurred in relatively high concentrations 62 240 ppm in comparison to other trace elements most of these trace elements exhibit positive correlations with sio 2 al 2 o 3 and tio 2 suggesting their occurrence in the detrital fraction which includes the clay minerals ree ranges between 129 5 and 617 ppm with strong positive correlations with p 2 o 5 indicating the occurrence of ree in the apatite chondrite normalized ree patterns showed lree enrichment over hree la yb n 2 3 5 4 and negative eu anomalies eu eu 0 75 0 89 the oolitic texture of the studied ores forms as direct precipitation of iron rich minerals from sea water in open space near the sediment water interface by accretion of feo sio 2 and al 2 o 3 around suspended solid particles such as quartz and parts of broken ooliths the fairly uniform size of the ooids reflects sorting due to the current action the geochemistry of major and trace elements in the ores reflects their hydrogenous origin the oolitic iron ores of the timsha formation represent a transgressive phase of the tethys into southern egypt during the coniacian santonian between the non marine turonian abu agag and santonian campanian um barmil formations the abundance of detrital quartz positive correlations between trace elements and tio 2 and al 2 o 3 and the abundance mudstone intervals within the iron ores supports the detrital source of fe this prediction is due to the weathering of adjacent land masses from cambrian to late cretaceous the texture of the apatite and the ree patterns which occurs entirely in the apatite exhibits a pattern similar to those in the granite thus suggesting a detrital origin of the hydroxyapatite that was probably derived from the precambrian igneous rocks determining the mode of occurrence and grain size of hydroxyapatite assists in the maximum utilization of both physical and biological separation of apatite from the aswan iron ores and hence encourages the use of these ores as raw materials in the iron making industry

the oleananes origin maturation and limits of occurence in southern nigeria sedimentary basins oleananes occur within well defined age and paleogeographic boundaries in the sedimentary province of southern nigeria thus signifying that the biomarkers may be analogous to index fossils in anambra syncline lower benue trough the biomarkers are found in rocks which are as old as late upper cretaceous in tertiary niger delta the concentration composition and distribution of the oleananes in rocks and oils are determined mainly by palaeodepositional environment and thermal history and are independent of age and geographical location of specific samples oleanane content varies with increasing burial depth with peak concentration coinciding within rm range 0 4 0 6 implying early generation of hydrocarbons from the basin s typically resin rich kerogens it is evident that the oleanane content parameter is superior to the hopane and sterane isomerisation indices for monitoring thermal maturation in the delta and for differentiating paralic from paralic marine source facies as well as early from late generated oils

paleozoic and mesozoic geological history of northeastern africa based upon new interpretation of nubian strata 1 the nubia terrain in southern egypt and northern sudan is the type area for strata of mainly cretaceous age because nubian sandstone or nubian formation or similar terms were used for strata in other areas and of other stratigraphic positions the name nubian has become meaningless this paper summarizes results of field work done in egypt and sudan since 1976 reconstruction of the tectonics and paleogeography of northeast africa since the early paleozoic permits division of all strata related broadly to the nubian into three cycles the paleozoic cycle cambrian to early carboniferous is mainly marine this cycle was interrupted by the collision of gondwana with northern continents the resultant karoo cycle representing purely continental sedimentation exte ded from the late cretaceous until the early jurassic the disintegration of pangea led to a third cycle that began in the late jurassic and resulted in the marginal marine to continental strata of the nubian cycle that ranges in age from late jurassic to latest cretaceous

sequencing events across the permian triassic boundary guryul ravine kashmir india abstract the permian triassic boundary ptb section at guryul ravine kashmir india comprises a 100 m thick apparently conformable succession of mixed siliciclastic carbonate sediments deposited in a deep shelf or ramp setting this section although long important in debates concerning placement of the ptb has not previously been the focus of an integrated chemostratigraphic study in the present study samples from a 20 m thick interval straddling the ptb were analyzed for major and trace element concentrations toc tic rees and organic 13c 15n to investigate contemporaneous environmental changes the guryul ravine section exhibits a sequence of discrete events that provide potentially important information about the character and cause s of the ptb two transient negative c isotopic excursions within the upper changxingensis zone predate the late permian event horizon lpeh i e the global mass extinction event by 200 400 kyr and are associated with the onset of a major eustatic rise and with secondary extinction peaks these excursions may record minor environmental disturbances prior to the main end permian crisis supporting an intrinsic mechanism such as volcanism and climate change rather than an extrinsic mechanism such as a bolide impact the onset of a large 4 0 to 4 5 sustained negative c isotope shift marks the lpeh which is located at the zewan khunamuh formation contact 260 cm below the biostratigraphically defined ptb the guryul ravine section exhibits a stepwise extinction pattern with the largest peak between the lpeh and ptb and a secondary peak just above the ptb a pattern similar to that observed in the meishan d gssp

facies and paleogeographic importance of the pre rift limestones from ne egypt sinai the depositional environments of the phanerozoic limestones of northeastern egypt were reconstructed based on microfacies and fossil content of the following limestonedominated sequences late carboniferous late anisian ladinian carnian bajocian kimmeridgian aptian albian late cenomaman early turonian late coniacian maastrichtian late paleocene early eocene the african craton in the south and the tethyan sea in the north mainly controlled the sedimentation of most phanerozoic strata they increase in thickness towards the north due to the gentle north northwest dip of the precambrian cratonal basement different subsiding areas enabled the filling of different depocenters since jurassic times with a maximum during the cretaceous

organic geochemistry and organic petrology of a potential source rock of early eocene age in the beaufort mackenzie basin abstract the biological marker compounds 17 h and 17 h 23 28 bisnorlupane have been identified in a coaly interval at about 3300 3320 m depth within the lower taglu sequence early eocene in the immiugak a 06 well in the beaufort mackenzie basin these biomarkers were previously only known to occur in the lower part of the richards formation and were thus used to infer that the richards was the source for most of the tertiary oils and condensates in the basin the discovery of bisnorlupanes in older much more organic rich rocks indicates that the previous oil source rock correlations may not have been correct and that the coals in the lower taglu sequence are likely the dominant effective source rock especially for the paleocene and early eocene reservoirs in the southern part of the mackenzie delta petrographic and rock eval analyses indicate that the lower taglu sequence coaly section should be mainly a source for gas but with some potential to expel liquids the level of thermal maturity inferred from rock eval tmax 432 438 c equivalent to about 0 65 0 75 ro vitrinite is slightly higher than that inferred from the measured reflectance fluorescence and foraminiferal colouration index which all indicate that the maturity at 3300 m is about 0 60 0 65 ro vitrinite equivalent at the gulf et al immiugak a 06 well site

biomarkers of holocene buried conifer logs from bella coola and north vancouver british columbia canada abstract the biomarker compositions of a holocene seep oil liquefied resin originating from a buried log of douglas fir pseudotsuga menziesii from bella coola bc canada and a holocene pine wood pinus sp sample from north vancouver bc canada were analyzed using gas chromatography mass spectrometry gc ms the total extract of the bella coola sample contains the sesquiterpenoid derivative calamenene and diterpenoids of the labdane abietane pimarane and phyllocladane classes a novel series of successively degraded labdane derivatives labdan 15 oic acid norlabdanoic acids drimenoic acid was detected in the polar fraction and a diagenetic pathway is proposed aromatic abietanes are the major components in the neutral fraction the neutral fraction of the pine wood contains two sesquiterpenoids calamenene cadalene diterpenoids of the abietane pimarane isopimarane and kaurane classes and a series of steroids 18 norabieta 8 11 13 triene dehydroabietin is the major component among the predominantly aromatic abietanes based on the compositions of the terpenoids it is concluded that the diagenesis of the pine and douglas fir logs probably occurred under anaerobic conditions leading to reductive reactions such as decarboxylation of resin acids with concurrent oxidation reactions to form the aromatic derivatives

tectonic evolution of kashmir basin in northwest himalayas abstract geomorphology has long been recognised as a key to evaluate the interplay between tectonics and landscape geometry in the regions of active deformation we use geomorphic signatures at varied spatial scales interpreted from srtm dem landsat etm data supplemented with field observations to review the tectonic evolution of kashmir basin in northwest himalayas geomorphic evidence is persuasive of a credible nnw sse trending dextral strike slip structure central kashmir fault ckf with the strike length of 165 km stretched centrally over the nnw sse length of the kashmir basin as a result of the strike slip motion and subsequent erosion significant deformation has taken place along the ckf in addition broad geomorphic architecture of the basin reveals typical pull apart characteristics hence we deduce that the kashmir basin has evolved as a pull apart quaternary sediment depression owing to the deformation along the central kashmir fault the spatial distribution pattern of seismic events neic catalogue 1973 2013 and gps measurements published collectively substantiate our geomorphic interpretations

cyclic terpenoids of contemporary resinous plant detritus and of fossil woods ambers and coals abstract cyclic terpenoids present in the solvent extractable material of fossil woods ambers and brown coals have been analyzed the sample series chosen consisted of wood remains preserved in holocene to jurassic sediments and a set of of ambers from the philippines copalite israel canada and dominican republic the brown coals selected were from the fortuna garsdorf mine and miocene formations on fiji the fossil wood extracts contained dominant diterpenoid or sesquiterpenoid skeletons and aromatized species were present at high concentrations with a major amount of two ring aromatic compounds tricyclic diterpenoids were the predominant compounds in the ambers aromatized derivatives were the major components consisting of one or two aromatic ring species with the abietane and occasionally pimarane skeletons the saturated structures were comprised primarily of the abietane and pimarane skeletons having from three to five carbon c1 c2 etc substituents kaurane and phyllocladane isomers were present in only minor amounts bicyclic sesquiterpenoids as saturated and partial or fully aromatized forms were also common in these samples but only traces of sesterterpenoids and triterpenoid derivatives were found the brown coal extracts were composed of major amounts of one and two ring aromatized terpenoids with a greater proportion of triterpenoid derivatives than in the case of the woods and ambers this was especially noticeable for the german coal where the triterpenoids were predominant open c ring aromatized structures were also present in this coal steroid compounds were not detectable but some hopanes were found as minor components in the german brown coal an overview of the skeletal structure classes identified in each sample as well as the general mass spectrometric characteristics of the unknown compounds are included in the present paper it can be concluded from these structural distributions that aromatization is the main process for the transformation of terrestrial cyclic terpenoids during diagenesis constituting a general pathway for all terpenoids

utilizing the geophysical and hydrogeological data for the assessment of the groundwater occurrences in gallaba plain western desert egypt the investigated region is located in the western desert fringes of the nile valley which requires studies of groundwater related to the many projects of land reclamation the key objective of this paper is to estimate the qualitative and geometrical features of the investigated aquifer using 60 vertical electrical sounding and time domain electromagnetic soundings allows us to suggest one possible model of the geometrical features of the local aquifer a hydrogeological monitoring has been undertaken to investigate the current groundwater situation at the gallaba plain such hydrological monitoring has not been undertaken before in detail the results show that the investigated region has high groundwater potentialities in two main aquifers which belong to pleistocene shallow fresh water and deep brackish water the lithological and structural elements contribute mainly to recharge and store the groundwater in the western part of the river nile in kom ombo graben the geochemical properties of the groundwater of the studied aquifers reflect meteoric water which is a fresh to slightly brackish water the small amount of groundwater salinity arises from silicate weathering and evaporation processes occurring in the aquifer matrix moreover most of the studied groundwater samples are unfit for human consumption such samples are very satisfactory for livestock and poultry purposes and they can be used for irrigation using modern and improved irrigation methods e g sprinkler and drip methods furthermore the hydrogeological monitoring of the concerned area indicates that it has high groundwater potentialities which will support its sustainable development

geology petrology and utilisation potential of some tertiary coals of the northeastern region of india abstract the coal bearing tertiary sediments of the northeastern region of india range in age from palaeocene to oligocene the coal deposits of meghalaya and the mikir and north cachar hills of assam contain generally thin seams of eocene age and were formed under stable shelf condition in peripheral platform areas the coal deposits of oligocene age occur in a narrow linear belt of overthrusts referred to as the belt of schuppen that extends from nagaland through assam to arunachal pradesh they were deposited in near shore deltaic wet forest swamps to marshy environments close to a geosynclinal trough the coal seams attain considerable thickness in the makum and namchik namphuk coalfields comparisons of coal type and rank variations in the eocene and oligocene coals indicate that the coals are broadly similar the coals are vitrinite rich 70 vol mineral matter free hereafter referred as mmf with moderate amounts of liptinite 8 vol mmf and inertinite 5 vol mmf the coals are high in volatile matter 38 57 dry mineral matter free basis hereafter referred as dmf sulphur 1 10 and hydrogen contents 4 9 dmf the carbon content of the coals ranges from 68 to 85 dmf the coals have caking properties in restricted zones the vitrinite reflectance of the oligocene coals r r 0 53 0 74 is slightly higher than that of the eocene coals r r 0 37 0 67 as per astm standard the eocene coals are classified as sub bituminous c to high volatile bituminous c and the oligocene coals as sub bituminous a to high volatile bituminous b microscopic examination of the coals shows a number of features which indicate that the northeastern coals may have generated hydrocarbons most of the eocene and oligocene coals are suitable for combustion and conversion e g liquefaction processes the coals with caking properties are being used at rates up to 5 10 in blends for metallurgical coke provided their sulphur content is below 3 and their ash content below 10

geomorphic evidence of unrecognized balapur fault segment in the southwest kashmir basin of northwest himalayas abstract the balapur fault bf is a high angle thrust fault reverse dipping 60 ne with an established length of 40 km striking nw se of the kashmir basin however geomorphic traces suggest that the strike of the bf propagates beyond what has been documented previously the present investigation aims to identify the unrecognized segment of the bf in the sw of the kashmir basin using hypsometric variability in longitudinal profiles knickpoints zones followed by validation through stream gradient index sl calculations of the rivers draining the area the longitudinal profiles of all the streams indicate prominent and consistent anomalies in the upper and mid reaches even on the coarse resolution data survey of india topographic maps 1 50 000 40 m dem srtm 90 m the profile anomalies in the upper reaches hard rock zone of the streams may be attributed to lithological contacts i e panjal trap agglomeratic slate shale limestone however the river profile convex segments and course deflection specifically in the mid reaches soft rock zone are most likely associated with recent tectonic activity geomorphic signatures suggest that these anomalies coincide with the strike of the recognized segment of the bf moreover the sl values of each stream express a clear agreement with the anomalies shown by the long profiles of the rivers hence we infer that the strike of the bf extends for a significant distance 95 km over the northeastern flank of the pir panjal range in the nw se direction

sedimentology palynostratigraphy and palynofacies of the late oligocene makum coalfield assam india a window on lowland tropical vegetation during the most recent episode of significant global warmth abstract the sedimentology palynofacies and pollen and spore assemblages together with observations on the preserved megaflora from the tirap coal mine assam india 27 17 20 n 95 46 15 e provide important insights into the composition and distribution of plant communities in a late oligocene tropical delta palaeolatitude approximately 18 n these insights take on additional significance because the late oligocene included the last significantly warm interval in earth s history before progressive neogene cooling to the present day icehouse the lower two thirds of a 188 m studied section represents lower delta plain environments with only a small degree of brackish water marine influence raised mires autochthonous swamps and allochthonous organic matter accumulations comprise the vitrinite rich high volatile bituminous b coals the upper third of the section represents upper delta plain environments with high sediment pass through here standing fossil forests attest to frequent inundation and recovery of the arborescent interfluve vegetation throughout the period of deposition of the studied section several 100 kyr sediment supply exceeded increases in accommodation space afforded by basin subsidence relative sea level rise a dominance of spores attributed to cyatheaceous and other fern taxa indicates that tree ferns and other pteridophytes were a major component of the vegetation throughout the environments represented by the section despite the absence of ferns in the megafossil record nypa and mangrove megaremains together with mangrove pollen and acrostichum spores attest to the presence of a mangrove community similar in composition to those of modern southeast asia palms and megathermal tree taxa such as those belonging to the malvaceae meliaceae alangiaceae anacardiaceae and pellicieraceae inhabited the interfluve and swamp forests perennial herbs of the family gunneraceae occur throughout the section palynofacies analysis shows a dominance of anoxic dysoxic environments with a small part of the lower part of the section exhibiting more oxic conditions associated with circumstantial evidence for mild marine possibly tidal influence most palynodebris fluoresce only weakly consistent with the relatively high rank for coals of this age a small number of reworked gondwanic permian grains suggest sediment erosion from the highlands to the north the late oligocene tropical delta vegetation has much in common with modern lowland wet megathermal forests from southeast asia however tree ferns appear more prevalent in the late oligocene

oil source correlation in tertiary deltaic petroleum systems a comparative study of the beaufort mackenzie basin in canada and the pearl river mouth basin in china abstract biomarker distributions in crude oil have been routinely used to investigate source rock character thermal maturity of migrated oil and lateral facies changes in the underlying source rocks in vertically drained basins case studies from tertiary deltaic systems that contain mixed oils from multiple source rocks in the beaufort mackenzie and pearl river mouth basins indicate that oil source correlation using the common fingerprint approach tends to favour the source that contains higher biomarker concentrations so biomarker concentrations as well as concentration independent yet source definitive parameters are needed to address the mass balance issues

geochemistry of crude oils from eastern indonesia high resolution geochemistry shows genetic relationships among 27 crude oils from eastern indonesia and suggests the ages and paleoenvironments of their source rocks oils inferred to originate from tertiary and triassic jurassic source rocks in the study occur north and south of 2is latitude respectively twenty oils mainly from irian jaya and sulawesi originated from tertiary marine marlstone source rocks that contained type ii iii kerogen deposited under suboxic conditions probably the upper miocene klasafet formation these low sulfur oils show high oleanane c26 24 nordia cholestane and pristane phytane ratios and 13c rich carbon isotope compositions high oleanane and 24 nordiacholestane ratios are diagnostic of tertiary oils and source rocks these oils account for about 16 of the estimated ultimate recoverable reserves in eastern indonesia

the paleogene vegetation and petroleum system in the tropics a biomarker approach abstract the present study investigates the biomarker signatures of sediments and crude oils to infer the paleovegetation from the two petroleum systems of assam basin eastern india they are classified as the paleocene middle eocene and the middle eocene oligocene petroleum systems the sediments are oil and gas prone with an early catagenetic stage of thermal evolution here we report tricyclic diterpanes such as rimuane pimarane rosane and isopimarane along with tetracyclic diterpanes ent beyerane phyllocladane kaurane from paleocene eocene coal bearing sediments and crude oils these diterpane biomarkers attest dominant contribution from conifers possibly from podocarpaceae and araucariaceae however diterpanes are not detected in oligocene sediments and oils crude oils from both paleocene eocene and oligocene reservoirs and organic rich sediments contain angiosperm biomarkers such oleanane and related triterpanes along with bicadinane a biomarker specific for the dipterocarpaceae family of angiosperms the equatorial position of india during early paleogene along with the presence of angiosperm signatures including dipterocarpaceae and gymnosperms reflect the emergence of tropical rainforest elements in eastern india absence of diterpenoids in oligocene samples and difference in angiosperm parameters from paleocene eocene samples suggests a change in source vegetation and organofacies

flood hazard assessment of upper jhelum basin using morphometric parameters morphometric parameters can be useful tools to provide general understanding of physical characteristics of drainage basin with respect to floods to evaluate the flood influencing factors in the upper jhelum basin we delineate the upper jhelum basin into ten sub basins followed by extraction of drainage network and morphometric parameters using advanced spaceborne thermal emission and reflection radiometer digital elevation model and topographic maps in geographic information system the overall flood potential was determined on the basis of compound value obtained for all morphometric parameters of each sub basin the analysis reveals that in general the northeastern segment of the upper jhelum basin reveals comparative higher flood potential than the southwestern segment the tributaries such as lidder veshav arapal arapat and bring exhibit greater potential to produce peak flows during rainfall events while the tributaries like dudhganga rambiara sandran romushi and sasara express moderate to low flood potential respectively the results of this study are likely to be very useful for effective flood hazard mitigation in upper jhelum floodplain

burial history and kinetic modeling for hydrocarbon generation part ii applying the galo model to saharan basins the galo basin evolution model described in makhous et al 1997 is applied to evaluate hydrocarbon generation and migration histories in several saharan basins three basins the oued el mya ghadames and illizi are located in the central and eastern parts of the saharan platform and are investigated in detail the ahnet mouydir timimoun reggane and other basins located in the southern and western parts of the platform are also studied the modeling results combined with geochemical data are used in a synthesis of the regional framework the thermal gradients in the ghadames and illizi basins are greater than those in the oued el mya basin this difference is attributed to differences in sedimentation and subsidence rates to less hercynian erosion and to fewer occurrences of evaporates in the akfadou region of the ghadames basin and in the mereksen region of the illizi basin in the southern and western parts of the illizi province the major subsidence occurred before hercynian uplift very moderate hercynian uplift in the ghadames and illizi basins did not involve a significant decrease of temperatures and organic matter maturation continued but at slower rates as a result the realization of hydrocarbon potential appears to be higher than would be expected favorable traps are located near subsided areas where the source shales particularly the devonian were not subjected to uplift and erosion in this respect the eastern sahara including the ghadames and illizi basins is a favored province analysis of the distribution of present day temperatures and paleotemperatures in the paleozoic sediments of the triassic province oued el mya ghadames trias and north illizi basins combined with effective source rock occurrences shows that favorable conditions for hydrocarbon generation during the paleozoic occurred essentially in the southern and southwestern parts of the province hydrocarbon generation during the mesozoic took place mainly in the central and northern parts of this province however some of the hydrocarbon accumulations in the northern and northeastern parts of oued el mya basin and in the northern and western ghadames basin were subsequently destroyed by the hercynian orogeny in the illizi basin ordovician and devonian structures are the most likely traps for hydrocarbons generated during the paleozoic whereas in the ghadames and oued el mya basins structures formed prior to the late cretaceous are preferentially favorable for oil accumulation gas accumulations are found in traps formed in the late cretaceous or later when source shales were buried to 3 3 3 5 km and more

geochemistry of loess paleosol sediments of kashmir valley india provenance and weathering abstract middle to late pleistocene loess paleosol sediments of kashmir valley india were analyzed for major trace and ree elements in order to determine their chemical composition provenance and intensity of palaeo weathering of the source rocks these sediments are generally enriched with fe 2 o 3 mgo mno tio 2 y ni cu zn th u sc v and co while contents of sio 2 k 2 o na 2 o p 2 o 5 sr nb and hf are lower than the ucc chondrite normalized ree patterns are characterized by moderate enrichment of lrees relatively flat hree pattern gd cn yb cn 1 93 2 31 and lack of prominent negative eu anomaly eu eu 0 73 1 01 average 0 81 paas normalized ree are characterized by slightly higher lree depleted hree and positive eu anomaly various provenance discrimination diagrams reveal that the kashmir loess paleosol sediments are derived from the mixed source rocks suggesting large provenance with variable geological settings which apparently have undergone weak to moderate recycling processes weathering indices such as cia ciw and pia values 71 87 83 83 and 80 57 respectively and a cn k diagram imply weak to moderate weathering of the source material

tertiary oils from upper assam basin india a geochemical study using terrigenous biomarkers abstract the upper assam basin in northeast india is a tertiary sub basin of the assam arakan basin hydrocarbons are present in the langpar formation upper palaeocene lakadong member of the sylhet formation lower eocene and the barail oligocene tipam lower miocene and girujan middle miocene formations in the basin a detailed study to understand the nature and origin of the oils from different stratigraphic horizons using terrigenous and other biomarkers has been carried out further the variation in maturities of oils occurring in different stratigraphic horizons has also been studied the study shows that rearranged oleananes oleananes and bicadinanes are present in these oils implying land plant input to their source rocks the oils have been classified into different groups using ratios of rearranged oleananes oleananes bicadinanes and steranes indicating presence of multiple source rocks in the basin with subtle variation in characteristics maturity studies show that oils from younger horizons barail tipam and girujan are more mature than oils from older horizons langpar and lakadong there is an apparent mismatch in maturity of oils as measured by different biomarker maturity parameters this is due to the mixing of two different charges of oils having different maturities and generated from two different source rock kitchens in the same reservoir principal component analysis pca of biomarker data has also been able to classify the oils into various groups a new parameter has been developed using ratios of rearranged oleananes for determining maturity of these oils

role of inversion tectonics in structural development of the himalaya abstract analysis of surface and subsurface structures variation of shortening amounts obtained by restoration of deformed cross sections and occurrence of younger hangingwall rocks over the older footwall rocks across the vaikrita thrust in the higher himalaya suggests reactivation of early normal faults as thrusts based on this an inversion tectonics model is proposed for structural development of the himalaya the model explains the geometrical shape of the himalaya as primary arcuation and helps in resolving superimposed deformation in the region

biomarker and n alkane isotope profiles for tertiary oils relationship to source rock depositional setting abstract biomarker and n alkane isotope profiles have been measured for 29 late cretaceous tertiary oils from se asia china papua new guinea new zealand and the u s a the results are interpreted with respect to six kinds of source rock depositional setting fluvio deltaic fd freshwater transitional tr lacustrine lac saline lacustrine sal marine deltaic md and marine carbonate mc a comparison of biomarker and n alkane isotope results suggests that parameters such as the oleanane hopane ratio may overestimate the higher plant contribution to marine oils the abundance of bicadinanes is much more variable than that of oleanane probably because of a specific association with the highly resinous dipterocarp hardwoods of se asia however traces do occur in an oil from outside the paleogeographic range of the dipterocarp family confirming that there is also a more general angiosperm source the bicadinane isomeric distribution is shown to depend on maturity leading to new maturity parameters which are resistant to even very heavy biodegradation retention indices based on the regular hopane series are provided for the main bicadinane and methyl bicadinane isomers and for a group of oleanane related triterpanes of unknown structure the presence of the latter compounds may indicate locally deposited as opposed to transported higher plant matter in the source source rock depositional setting is the primary control on the shape of the n alkane isotope profile with negatively sloping curves being characteristic of fd and tr oils and flat or positively sloping curves typical of marine oils the difference is probably related to the bacterial reworking of higher plant matter in the fd environment a slight isotopic anomaly at n c 17 correlates with the abundance of algal derived steranes and may indicate a minor marine contribution to the source of an fd oil

correlation of the major late jurassic early tertiary low and highstand cycles of south west egypt and north west sudan the mainly continental deposits of northwest sudan and south west egypt have been correlated with coeval shallow marine and marine deposits in northern egypt along a north south running cross section based on surface and subsurface data the palaeodepth curve of northern egypt illustrates the gradual seal level rise reaching its maximum during the late cretaceous with conspicuous advances during the aptian and late cenomanian a general highstand is also recorded during the campanian maastrichtian in north west sudan a detailed facies correlation is given for the aptian and late cenomanian highstand in western egypt the correlation of the cenomanian bahariya and maghrabi formations displays short term relative sealevel fluctuations the interpretation illustrates the extensiveness of related erosional processes in the hinterland partly intensified by temporarily uplift of the uweinat aswan high in the south regional uplift and constant erosion took place in south west egypt during coniacian and santonian times the regional stratigraphic gaps and uncertain interpretation of the bahariya uplift are induced by the influence of the trans african lineament especially during the late cretaceous low stand fluvial sheet sandstones characterized by non cyclic sequence development and high facies stability occur especially in the neocomian and early turonian during the barremian and albian fluvial architecture changes to more cyclic fluvial sequences and increasing soil formation due to increasing subsidence more humid climatic conditions and the generally rising sea level culminating in the extensive shallow marine abu ballas and maghrabi formations

sesquiterpanes diterpanes and other higher terpanes in oils from the taranaki basin of new zealand abstract the bi tri and tetracyclic terpenoids in crude oils from the taranaki basin of new zealand have been studied the distribution of c14 c15 and c16 bicyclanes was essentially invariant amongst the various fields a suggestion is made that the proportion of rearranged to total drimanes may be related to maturity and the ratio of homodrimane to drimane may be related to depositional environment mass spectra are reported for a number of unidentified sesquiterpanes including possibly norbisabolane and bisabolane the distribution of bi tri and tetracyclic diterpanes was very similar to that of crude oils from the gippsland basin of south east australia the occurrence of rimuane was confirmed 8 h labdane was identified and 4 h 18 norisopimarane was tentatively identified isopimarane dominated the diterpane distribution of oils from the maui field in the south west of the basin and its abundance gradually diminished in a north westerly direction until it became a minor component of oil from the new plymouth field this trend coincided with an increase in the complexity of the triterpane distribution and with the oleanane content of the oils these northwards trends also followed the evolution of coal deposits in the region the diterpanes in these oils had the same structure as those which occur in extant trees of the araucariaceae and podocarpaceae which flourish in new zealand today and did so even more extensively in the past coal measures formed from forests of such trees are probably the source of the diterpanes a situation analogous to that in the gippsland basin of south eastern australia tricyclanes of the cheilanthane series were not detected in any of the taranaki oils lending support to the view that these tricyclanes occur most abundantly in oils derived from marine sources c24 tetracyclanes secotriterpanes occurred abundantly in all the oils as they do in terrigenous oils from other parts of the world

the paleocene eocene carbon isotope excursion in higher plant organic matter differential fractionation of angiosperms and conifers in the arctic abstract a study of upper paleocene lower eocene p e sediments deposited on the lomonosov ridge in the central arctic ocean reveals relatively high abundances of terrestrial biomarkers these include dehydroabietane and simonellite derived from conifers gymnosperms and a tetra aromatic triterpenoid derived from angiosperms the relative percentage of the angiosperm biomarker of the summed angiosperm conifer biomarkers was increased at the end of the paleocene eocene thermal maximum petm different when observed with pollen counts which showed a relative decrease in angiosperm pollen stable carbon isotopic analysis of these biomarkers shows that the negative carbon isotope excursion cie during the petm amounts to 3 for both conifer biomarkers dehydroabietane and simonellite comparable to the magnitude of the cie inferred from marine carbonates but significantly lower than the 4 5 of the terrestrial c29 n alkane m pagani n pedentchouk m huber a sluijs s schouten h brinkhuis j s sinninghe damste g r dickens and the iodp expedition 302 expedition scientists 2006 arctic s hydrology during global warming at the paleocene eocene thermal maximum nature 442 671 675 which is a compound sourced by both conifers and angiosperms conspicuously the angiosperm sourced aromatic triterpane shows a much larger cie of 6 and suggests that angiosperms increased in their carbon isotopic fractionation during the petm our results thus indicate that the 4 5 c29 n alkane cie reported previously represents the average cie of conifers and angiosperms at this site and suggest that the large and variable cie observed in terrestrial records may be partly explained by the variable contributions of conifers and angiosperms the differential response in isotopic fractionation of angiosperms and conifers points to different physiological responses of these vegetation types to the rise in temperature humidity and greenhouse gases during the petm

the ratios of dibenzothiophene to phenanthrene and pristane to phytane as indicators of depositional environment and lithology of petroleum source rocks abstract the ratio of dibenzothiophene to phenanthrene and the ratio of pristane to phytane when coupled together provide a novel and convenient way to infer crude oil source rock depositional environments and lithologies such knowledge can significantly assist in identifying the source formation s in a basin thereby providing valuable guidance for further exploration the ability to infer this information from analysis of a crude oil is especially valuable as frequently the earliest samples in a new area may be shows and or drill stem test samples from exploratory wells which are characteristically drilled on structural highs stratigraphically remote from the source formation s a cross plot of dibenzothiophene phenanthrene versus the pristane phytane ratios measured on seventy five crude oils from forty one known source rocks ranging in age from ordovician to miocene consistently classified the oils into the following environment lithology groups marine carbonate marine carbonate mixed and lacustrine sulfate rich lacustrine sulfate poor marine and lacustrine shale and fluvial deltaic carbonaceous shale and coal the dibenzothiophene phenanthrene ratio alone is an excellent indicator of source rock lithology with carbonates having ratios 1 and shales having ratios the dibenzothiophene to phenanthrene and the pristane to phytane ratios can also be used to classify source rock paleodepositional environments the classification scheme is based on the premise that these ratios reflect the different eh ph regimes resulting from the significant microbiological and chemical processes occurring during deposition and early diagenesis of sediments the dibenzothiophene phenanthrene ratio assesses the availability of reduced sulfur for incorporation into organic matter and the pristane phytane ratio assesses the redox conditions within the depositional environment interpretation of these ratios has been aided by quantitative biomarker analysis and by carbon isotope data for pristane and phytane obtained by gas chromatography isotope ratio mass spectrometry

optical properties of some tertiary coals from northeastern india their depositional environment and hydrocarbon potential abstract in northeastern india the coalfields of arunachal pradesh assam and nagaland are disposed along a linear belt of overthrusts known as the belt of schuppen where tertiary strata have been folded and dispersed into a number of thrust slices the coal bearing sediments in this belt are associated with the baragolai and tikak parbat formations of the barail group oligocene in meghalaya the tertiary sediments were deposited on a stable shelf along the periphery of the shillong plateau they are almost undisturbed and sub horizontal in attitude the coal seams are associated with the sylhet tura formations palaeocene of the jaintia group the chemical properties of these coals show characteristics of both low on volatile matter content and high on moisture and calorific value ranks the coals have a low softening temperature and a high swelling index volatile matter hydrogen and sulphur contents besides having the highest tar yield among indian coals the syncrude produced from these coals shows similarities with the identical fraction of crude oil from nahorkatiya oilfield assam the coals from the belt of schuppen and meghalaya are non banded and bright in nature microscopically their humic components are strongly decomposed with a common to frequent association of framboidal pyrite and calcite concretions the coals are vitrinite rich 52 0 80 0 with moderate amounts of liptinite macerals 5 8 16 2 the inertinite content is low 4 6 11 0 to occasionally high 30 0 fluorescing vitrinite and liptinite macerals constitute 46 5 to 83 5 by volume m m f perhydrous vitrinite liptodetrinite and resinite are the most common fluorescing macerals the rank of the coal samples r 0 max 0 57 0 74 ranges between high volatile bituminous c and b stages the assam coals are higher in rank than those of nagaland and meghalaya in northeastern india during the palaeocene and oligocene epochs peat swamps formed in situ from tropical mangrove rich angiospermous forest vegetation the palaeocene coals in meghalaya were formed in estuaries or lagoons however the coal forming phase ceased shortly due to prolonged marine transgression the oligocene coals in the belt of schuppen were formed during a regressive phase in back water lagoons or brackish water swamps on a prograding delta complex the hydrocarbon potential mg ch g c org of the coal samples from northeastern india has been theoretically deduced on the basis of their kerogen types following mukhopadhyay et al 1985 the presumed hydrogen index varies from 250 to 430 and 300 to 470 mg ch g c org respectively for coals in the belt of schuppen and meghalaya evidence indicates that in arunachal pradesh assam and nagaland oil has been generated from kerogen types ii b and ii a in the oligocene mudstone siltstone shale association of the coal measures of barail group in meghalaya no oil is known so far nevertheless the predominance of kerogen types ii a and ii b in coals indicates a good oil potential in the palaeocene sediments of the jaintia group

plate tectonics and cratonal geology in northeast africa egypt sudan the stratigraphical interpretation of the strata of nubia allows for the first time in connection with structural petrological and sedimentological investigations to reconstruct the geological development of this cratonal area after cratonization during the panafrican event extensional trends in wsw ene direction caused a structural relief striking nnw sse the collision between gondwana and the northern continents during the carboniferous resulted in the uplifting of large parts of the northeast african plate and was accompanied by more or less east west striking faults and magmatic intrusions erosion of paleozoic sediments in middle and southern egypt and reversal of the main drainage direction was the consequence this caused deposition of karroo type strata in northern sudan including glacial deposits at the base along the sudanes egyptian border

the himalayan passive margin from precambrian to cretaceous times abstract the himalaya passive margin should be separated into the indian himalaya and the pakistan himalaya divided by the nanga parbat haramosh basement uplift in the northwestern syntaxes the indian passive margin shows a complex history involving splitting of microcontinents off the northern gondwana margin from early paleozoic times until the jurassic in contrast the pakistan himalaya formed part of the stable indian shelf until separation from africa started in the jurassic each margin has a distinct stratigraphic history until the mid mesozoic after which they show similar histories until the tertiary the himalaya mountains in india consist of three distinct tectonic units juxtaposed during the neogene by southward thrusting of the northern indian precambrian to mesozoic passive margin the lesser himalaya on the south forms a late precambrian passive margin usually directly overlain by late cretaceous to tertiary clastics its stratigraphy is closest to that of the indian shield in contrast the high himalaya has a thin ordovician to carboniferous shelf sequence deposited after early ordovician deformation and granite intrusion above this thick permian and mesozoic shelf sequences mark the separation of continental blocks off the northern indian margin and the opening of the neotethys ocean the north himalaya formed the slope and basin of this ocean and consists of reactivated paleozoic gneiss domes overlain by thick mesozoic sediments which pass in the northeastern himalaya into an enormously thick sedimentary sequence resting on oceanic crust paleomagnetic and structural evidence indicates at least 500 km of southward thrusting along the main central thrust between the lesser and high himalaya this thrusting together with a further 250 km of erosion at the front of the nappes has removed the entire inner shelf of the himalaya passive margin and can explain the startling contrast between the high and lesser himalaya stratigraphic sequences but there are still discrepancies particularly in the eastern himalaya where precambrian basement is juxtaposed with the north himalaya mesozoic slope these discrepancies can be partly resolved by strike slip movements roughly parallel to the himalaya which have removed parts of the northern indian passive margin such faults of the requisite orientation displacement and age occur in southeast asia where their cumulative displacements can add up to several thousand kilometres similar faults of undoubted pre tertiary age occur in the pakistan himalaya here the passive margin shows a much simpler history of jurassic to miocene subsidence

source rock evaluation and sequence stratigraphic model based on the palynofacies and geochemical analysis of the subsurface devonian rocks in the western desert egypt abstract the paleozoic rocks are the least explored among the subsurface successions in the western desert of egypt this contribution submits a significant record for the palynofacies and geochemical analysis for an important division of the subsurface paleozoic rocks from faghur 1 and nw d302 1 boreholes the palynofacies of the devonian sediments of zeitoun formation extensively verified and classified the palynofacies classification depended on the statistical techniques of cluster and correspondence analysis the cluster analysis discriminated four classes of palynofacies in r mode which are brown wood palynofacies class r1 spore palynofacies class r2 aom opaque phytoclasts palynofacies class r3 and marine phytoplankton palynofacies class r4 in the q mode the cluster analysis revealed three palynofacies types which are palynofacies type c palynofacies type b palynofacies type a the combination of cluster and correspondence analysis is employed to interpret the evolution of basin dynamics and the mechanisms that controlled the deposition of the devonian rocks three basic environmental settings were recognized and they include 1 oxic highly proximal shelf setting 2 oxic proximal shelf setting and 3 oxic distal shelf the high oxygenation levels are confirmed by the inorganic geochemical analysis of fe ts fe and ts toc in the samples from faghur 1 borehole the paleoenvironmental reconstruction is used to identify four 2nd order stratigraphic sequences in the studied sections which are devseq1 devseq2 devseq3 and devseq4 these sequences are systematically described and correlated with their equivalent global devonian sequences the palynofacies investigation is integrated with the inorganic and organic geochemical analysis to evaluate the potentially of hydrocarbon generation from the probable source rocks in the studied sections and its onset timing the identified kerogen types are mostly mature tai range between 2 and 3 and tmax range between 427 and 439 c gas prone type iii with poor organic enrichment toc

contrasted distributions of triterpene derivatives in the sediments of lake caco reflect paleoenvironmental changes during the last 20 000 yrs in ne brazil lipid fractions extracted from sediment layers deposited in a small brazilian lake during the last 20 000 yrs were investigated by gas chromatography mass spectrometry considerable differences in the distribution and the amount of triterpene derivatives in the aliphatic as well as in the aromatic fractions were observed all along the series although no precise identification of these compounds was undertaken our interpretation of mass spectral data allowed us to discriminate between des a triterpenes mono and triaromatic derivatives of pentacyclic triterpenes and a series of compounds tentatively identified as diaromatic derivatives of tetracyclic triterpenes the largest compound diversity was found in the lowest levels of the series dated back to the end of the last glacial maximum when good preservation of terrestrial plant debris was ensured by rapid burial in a semi arid climate then except for a period corresponding to the younger dryas only des a lupane was detected in significant amounts the high predominance of des a lupane is interpreted to result from the development of a belt of eleocharis sp spike rush that filtered most of organic inputs from the catchment and was the site of des a lupane production and exportation towards the lake centre during the younger dryas a strong influx of des a lupane is attributed to the destruction of the spike rush belt consecutive to the lowering of the lake level under drier conditions the temporary destruction of this barrier allowed other triterpene derivatives to reach the lake the distinct dynamics of des a and aromatic triterpene derivatives under variable medium conditions led us to hypothesis that these two families of compounds derive from distinct pools that contributed differently to the sediment depending on environmental and climatic conditions des a lupane was most probably produced in sub aquatic conditions within the belt of spike rush conversely aromatic derivatives of triterpenes could have resulted from the degradation of their biological precursors within reducing micro environments in the catchment

structural setting and kinematics of nubian fault system se western desert egypt an example of multi reactivated intraplate strike slip faults abstract detailed surface geological mapping and subsurface seismic interpretation have been integrated to unravel the structural style and kinematic history of the nubian fault system nfs the nfs consists of several e w principal deformation zones pdzs e g kalabsha fault each pdz is defined by spectacular e w wnw and ene dextral strike slip faults nne sinistral strike slip faults ne to ene folds and nnw normal faults each fault zone has typical self similar strike slip architecture comprising multi scale fault segments several multi scale uplifts and basins were developed at the step over zones between parallel strike slip fault segments as a result of local extension or contraction the nne faults consist of right stepping sinistral strike slip fault segments e g sin el kiddab fault the nne sinistral faults extend for long distances ranging from 30 to 100 kms and cut one or two e w pdzs two nearly perpendicular strike slip tectonic regimes are recognized in the nfs an inactive e w late cretaceous early cenozoic dextral transpression and an active nne sinistral shear

oleananes in oils and sediments evidence of marine influence during early diagenesis abstract the oleananes as markers for the angiosperms provide valuable source and age information when present in an oil nevertheless they are not quantitatively related to the land plant input and indeed their presence reflects only a small leak in diagenetic processes leading primarily to aromatic oleanoids because they are minor products the abundance of oleananes in terrigenous oils and sediments may be highly sensitive to changes in early diagenetic conditions here we present evidence that contact of plant matter with seawater during early diagenesis enhances the expression of oleananes in a mature sediment or oil oleananes are absent or present at very low concentrations in samples from the base of an eocene coal seam affected by postdepositional seawater intrusion however their abundance increases toward the top of the seam in correlation with organic sulphur dibenzothiophene phenanthrene and the homohopane index similarly in deltaic sediments from the south sumatra basin oleanane hopane is strongly correlated with indicators of marine influence such as c 27 c 29 steranes and the homohopane index in each case increasing oleanane abundance is accompanied by a reduction in the extent of aromatisation and for the south sumatra basin the proportion of a ring contracted oleananes an angiosperm derived miocene coal from the philippines deposited under freshwater conditions shows abundant aromatic oleanoids but no oleananes these results show that oleananes need to be used with caution as age and source markers in fluvio deltaic and lacustrine petroleum systems on the other hand their sensitivity to early diagenetic conditions may make them useful in locating effective source rocks in such systems

terpenoid composition and botanical affinity of cretaceous resins from india and myanmar abstract fossil resins from the cretaceous sediments of meghalaya india and kachin myanmar burma were analysed using curie point pyrolysis gas chromatography mass spectrometry and thermochemolysis gas chromatography mass spectrometry to help elucidate their botanical source the major pyrolysis products and methyl esterified thermochemolysis products of both the resins were abietane and labdane type diterpenoids with minor amount of sesquiterpenoids the thermochemolysis products also included methyl 16 17 dinor callitrisate methyl 16 17 dinor dehydroabietate and methyl 8 pimaren 18 oate the latter two from just the myanmarese resin the exclusive presence of both labdane and abietane diterpenoids and the lack of phenolic terpenoids may suggest that the studied cretaceous resins were derived from pinaceae pine family conifers

coexistent pre existing extensional and subsequent compressional tectonic deformation in the kashmir basin nw himalaya abstract this paper presents a new interpretation of overlapping differential deformations and likely causes of the structural heterogeneity within the kashmir basin representing a prominent and distinctive strain feature in nw himalaya the broad geomorphic expression of the kashmir as an elongated nw se trending sedimentary trough is inconsistent with general compression governing structural trend and deformation pattern of 2500 km long himalayan frontal thrust zone in addition to the general extensional geometry there are prominent anomalous deformation features at varied spatial scales in the basins that imply dominance of extensional tectonics we infer that contrary to the overall compression dominant mechanism of the himalaya the apparent extensional geometry of the basin connotes orogen parallel extensional deformation pull apart triggered by oblique convergence in the nw himalaya moreover we construe that the comparatively younger contractile positive features in form of the geomorphic convexity push up accompanied by out of sequence reverse faulting balapur fault hereafter called as bf within the basin which is generally believed to be associated with the uplift along ne dipping southern thrust complex mbt mct possibly resulted due to the tectonic reversal positive inversion the presence of the compressional features within the locally predominant extensional setting is suggestive of the basin s hybrid character where variable tectonic regimes earlier extension and subsequent compression seem to be coexistent

aliphatic and aromatic triterpenoid hydrocarbons in a tertiary angiospermous lignite abstract the hydrocarbon biomarker assemlage of a liptinite rich early tertiary angiospermous lignite has been characterized the biomarker fistribution for the lignite confirms the low maturity and previous paleobotanic interpretations the aliphatic hydrocarbon fraction consists predominantly of n alkanes showing a strong odd carbon predominance and numerous de a triterpenoids and triterpenoids derived from higher plants bacterially derived triterpenoids were represented primarily by homohopanes and hopenes the aromatic hydrocarbon fraction contains a series of mono di and triaromatic de a triterpenoids and mono tri and tetraaromatic triterpenoids derived from higher plants the concentration and abundance of monoaromatic triterpenoids containing one to three additonal degress of unsaturation have not seen previously observed in a single deposit as such a diagenetic scheme for angiosperm derived triterpenoids is presented which confirms and extends previous hypothesis

improved understanding of the petroleum systems of the niger delta basin nigeria biomarker and n alkane compound specific stable carbon isotope analyses csia were carried out on 58 crude oil samples from shallow water and deepwater fields of the niger delta in order to predict the depositional environment and organic matter characteristics of their potential source rocks using a source organofacies prediction approach from oil geochemistry the presence in the western deepwater oils relatively abundant c27 steranes c30 24 n propyl cholestane low oleanane index relatively low pr ph ratios gammacerane and positive to nearly flat c12 c30 n alkane compound specific stable carbon isotope profiles suggests that the source facies that expelled these oils contain significant marine derived organic matter deposited under sub oxic and stratified water column conditions this contrasts with the terrigenous organic matter dominated source rocks accepted for shallow water niger delta oils oils in the shallow water accumulations can be separated into terrigenous and mixed marine terrigenous families the terrigenous family indicates expulsion from source rock s containing overwhelmingly higher plant source organic matter average oleanane index 0 48 high c29 steranes as well as having negative sloping n alkane isotope profiles oxic source depositional conditions pr ph 2 5 and non stratified conditions absence to low gammacerane content are inferred for the terrigenous family the mixed marine terrigenous family has biomarker properties that are a combination of the deepwater and terrigenous shallow water oils bitumen extracts of the sub delta late cretaceous araromi formation shale in the dahomey basin are comparable both molecularly and isotopically to the studied western deepwater oil set but with an over all poor geochemical correlation this poor geochemical match between araromi shale and the western deepwater oils does not downgrade the potential of sub delta cretaceous source rock contribution to the regional oil charge in the deepwater niger delta

abor volcanics further evidence for the birth of the tethys ocean in the himalayan segment the himalayan region has a record of several phases of igneous activity which indicate a continued n s orientated tensional regime since at least late precambrian time though the earlier volcanic eruptions were restricted both in time and space the late carboniferous triassic activity was widespread in terms of both the time interval and area covered the abor volcanic activity in the eastern syntaxial bend of the himalayan fold belt is coeval with the initiation of late carboniferous triassic panjal trap volcanism of the western syntaxial bend and eruption of the sikkim lavas chemical characters of the abor volcanics indicate 1 a within plate rift tectonic setting of the lava eruptions 2 a transitional nature between tholeiitic and alkalic compositions 3 relative enrichment in incompatible elements and 4 high fe ti values similar to many such basalts erupted in the regions of active lithospheric rifting the olivine free nature a linear trend for mgo and low co contents of the studied rocks are suggestive of high pressure olivine fractionation for the generation of the bulk chemistry however large variations in the incompatible element abundances and ratios of rocks at a similar fractionation stage discount the evolution of the lava chemistry exclusively by simple fractionation or partial melting processes instead these characters together with the low zr nb ratio and within plate rift tectonic setting suggests the modification of an upper mantle source region possibly by fluid phase co 2 immediately before the partial melting and lithospheric rifting combining geology of the region with the geochemistry and inferred tectonic setting of these rocks the lava eruptions are suggested to have been associated with the 9rift valley stage9 of the tethys ocean formation in the present himalayan region

thermal and tectonic evolution of the kashmir basin vis a vis petroleum prospects abstract investigation of the formation of peri atlantic basins and evaluation of the mechanism of lithospheric break up provide a guide for understanding the pre collision history of the himalayan region as an example the kashmir basin is discussed the present form of the kashmir basin is that of a graben bounded by two horsts the stratigraphic succession shows a complete record of shallow marine sedimentation from the cambrian to middle carboniferous in the upper carboniferous the depositional environment changed to continental type accompanied by large scale erosion especially on the western side and the deposition of agglomeratic slate and then in the lower permian by the panjal trap volcanism whilst the eastern side after this continental phase again subsided and received marine sediments until the end of the triassic the western side experienced repeated uplift and volcanism gravity and seismic data indicate the presence of high density material and a shallow depth of the moho beneath the basin and also the eruption of the panjal trap lava along two deep seated faults f1 and f2 on the flanking horsts with dips towards the present indus tsangpo suture after the upper carboniferous a continental phase is noted all over the himalaya this is thought to mark the initiation of the break up of the indian plate from the siberian cathysian block which finally occurred at the end of the triassic based on the stratigraphie and tectonic set up of kashmir in particular and the whole himalaya in general a model is presented to explain the formation of the kashmir basin good compatibility of the model with observed tectonic and stratigraphie aspects of kashmir and the whole himalaya is found the geothermal history of different strata in this basin indicates promising conditions for hydrocarbon generation a few of the more promising strata are identified for intensive investigations

geochemical characterization and source investigation of oils discovered in khoraghat nambar structures of the assam arakan basin india abstract we examined the geochemical compositions of the newly discovered bokabil and sylhet oils and of the extracts of potential source rock samples from the khoraghat nambar area of the assam arakan basin india stable carbon isotopic compositions and a number of biomarkers indicate that oils in the bokabil formation early to middle miocene can be correlated across the khoraghat and nambar fields however oil from the sylhet formation middle to late eocene is distinct from those in the bokabil formation late eocene to early oligocene barail coal shale and middle to late eocene kopili shale sequences are identified as potential source rocks both strata contain organic matter predominantly derived from higher land plants however different organofacies exist for barail coal shale and kopili shale sequences that can be distinguished by the stable carbon isotopic compositions and biomarker distributions an oil source correlation study shows that barail rock extracts are genetically correlatable with the bokabil oils whereas kopili rock extracts have similar source specific parameters to those of the sylhet oil thus the study suggests the presence of two petroleum systems in the khoraghat nambar area the barail bokabil and the kopili sylhet petroleum systems barail and kopili sediments from the study area are of lower maturity than the oils suggesting that the actual source strata are more mature equivalents likely to be present in the naga schuppen zone therefore areas in and around the naga schuppen zone where better reservoir facies are expected are favoured targets for further exploration

sesqui and diterpenoid biomarkers preserved in taxodium rich oligocene oxbow lake clays weisselster basin germany several diterpenoids of the abietane pimarane and phyllocladane type and three cadalanetype sesquiterpenoids have been identified in the organic solvent extracts of lower oligocene clay sediments haselbach strata saxony germany the sediment contains needles and cone scales of a fossil taxodium species which represents the only conifer in the samples a clear correlation between the observed conifer biomarkers and taxodium is evident apart from diterpenoids detected previously in other sediments a new diaromatic totarane diterpenoid is reported in isolated fossil and recent taxodium needles and cone scales as well as in the haselbach clays a phenolic diterpenoid of the abietane type ferruginol has been identified the results indicate that the taxodium rich clay samples contain several diterpenoids which so far have been used as biomarkers for other conifer families and thus the chemotaxonomical use of diterpenoid biomarkers for the differentiation of fossil conifer families has to be revised

chemostratigraphic evidence of higher plant evolution in the taranaki basin new zealand correlation between palynological and biomarker records of higher plant development during the cretaceous and paleogene in taranaki basin new zealand is good gymnosperms particularly podocarps were the chief members of coastal plain swamp flora during the late cretaceous and contributed significant quantities of diterpanes often dominated by isopimarane to organic rich sediments angiosperms increased in relative abundance through the paleocene and became the dominant higher plants in the eocene their contributions to coaly sediments are characterized by various triterpanes particularly 18 h oleanane and its c24 a ring degraded counterpart this change in dominance of higher plant groups can be followed by the use of an angiosperm gymnosperm index agi based on the relative concentrations of selected triterpanes and diterpanes in mz 191 and mz 123 mass chromatograms plant biomarker distributions do not provide as precise age indications as do pollen assemblages but they may be more representative of the vegetation growing in a particular area of a peat swamp

palaeoenvironments of the permian triassic transition sections in kashmir india abstract detailed measurements of two permian triassic boundary sections at guryul ravine and pahlgam in kashmir indicate continuous sedimentation across the boundary though with a marked change from shallow storm influenced shelf to deeper shelf below wave base successive shell beds through the 2 5 m thick transitional latest permian section at guryul formed as in situ accumulations with little sign of either erosional breaks or condensation faunal change takes place gradually in the late permian transition beds as elsewhere in the tethyan sections there is no major event layer at the permian triassic boundary and little evidence for dysaerobic conditions both the kashmir and east greenland permian triassic sections have sedimentation rates that are orders of magnitude greater than at the condensed meishan reference section they show that the end permian extinction was associated with transgression but not with immediate onset of anoxic conditions macrofaunal extinction seems associated with reduction in primary production which would also explain the dwarfism of fossils found in all permian triassic sections studied so far

comment on earthquake geology of kashmir basin and its implications for future large earthquakes by shah 2013 kashmir basin fault and its tectonic significance in nw himalaya jammu and kashmir india by shah 2015 kbf without any additional structural kinematic geologic or geomorphic data in support therefore this comment aims to clarify the confusions created by shah 2013 2015a and it is in this context we provide a review of the bf no active faults out of sequence thrusts tectonic discontinuities were known north of mbt or mct in the kashmir basin except a few nw se suspected fault segments with the collective length of 45 km along nw quaternary deposits mapped from aerial photographs and corona satellite images nakata et al 1991 and a south facing scarp delineated as a possible active fault using landsat satellite images yeats et al 1992 subsequent investigations revealed that the southwest facing scarp yeats et al 1992 is a high angle thrust fault reverse with an average northeast 60 dip and nw se strike length of 40 km ahmad 2010 madden et al 2010 2011 ahmad and bhat 2012 figs 1 2 3 the structure was named as bf because of its exposure on the left bank of rambiara river tributary of jhelum river at balapur village n 33 75 e 74 83 in shupiyan district of jammu and kashmir state india ahmad 2010 ahmad and bhat 2012 with an unknown depth the bf cuts across nw se unconsolidated karewa deposits plio pleistocene soft sediments devoid of gouge and breccia however rotated gravels at the fault contact have been marked ahmad and bhat 2012 stratigraphic relations show that the fault has uplifted the lower pleistocene methawoin member sand sandy clay clay silt and lignite bands of the lower karewa and juxtaposed it to the middle pleistocene shupiyan member gravels mostly composed of panjal trap fragments of the upper karewa bhatt 1989 subsequently the bf was firmly established by paleoseismic investigation and field data madden et al 2010 2011 ahmad et al 2013 ahmad 2014 an optically stimulated luminescence osl sample collected from fluvial deposits a few meters above the lower strath gives comment

petroleum geochemistry of a part of upper assam basin india a brief overview abstract the upper assam tertiary sedimentary basin is an important petroleum province with reservoir rocks ranging in age from upper paleocene to miocene the bulk of the oil production is from the barail oligocene and tipam miocene formations promising hydrocarbon pools have been discovered recently in upper paleocene lower eocene formations prolific source rocks occur within the barail oligocene formation langpar formation upper paleocene and lakadong theria member of sylhet formation of upper paleocene lower eocene age the source rocks contain predominantly type ii organic matter and are thermally immature to early mature biomarker ratios indicate the dominance of land plant derived kerogen the barail and tipam oils have moderate gravity and significant wax contents the physical and chemical characteristics of the paleocene eocene crude oil is similar to that produced from younger horizons within the basin with the exception of minor quantities of heavy viscous crude oils observed in a few wells multivariate analysis including principal components analysis and factor analysis of fluorescence data and principal components analysis of biomarker data indicate that the barail oligocene and tipam miocene oil have been derived from barail source rocks with a possible contribution from eocene source rocks these preliminary studies have not provided conclusive evidence for the source of the eocene oils although geological factors indicate that the source rocks are probably the interbedded shales coals occurring within the upper paleocene lower eocene sediments

molecular composition and chemosystematic aspects of cretaceous amber from the amazonas araripe and reconcavo basins brazil amber occurrences in brazil are rare in this regard the molecular composition of three such fossil resin samples from brazilian cretaceous sedimentary basins has been analyzed to determine the botanical origin of the resins the samples were collected from the amazonas alter do chao formation araripe santana formation crato member and reconcavo maracangalha formation caruacu member basins the mono sesqui and diterpenoids in the extracts were used as chemosystematic markers when compared with terpenoids in extant conifers the compounds were mainly diterpenoids and their degradation products from the labdane podocarpane pimarane and isopimarane classes in addition to paraffins methoxyphenols and carboxylic acids tetracyclic diterpenoids such as phyllocladane kaurenol and kauranol were also present the biomarker compositions are certainly typical for conifers and given the absence of triterpenoids and diterpenoids such as ozic acid angiosperms can be excluded as a botanical source the absence of phenolic diterpenoids ferruginol totarol and their derivatives excludes podocarpaceous affinities for the ambers from the amazonas and araripe basins the fossil records of the embedding sediments e g araucariaceae pollen and leaves support the proposal of an araucariacae origin for these ambers but cupressaceae and cheirolepidiaceae cannot be excluded on the other hand the presence of phyllocladane and kaurane derivatives is evidence for araucariaceae or podocarpaceae origins for the amber from the reconcavo basin but cupressaceae cannot be excluded