fluviokarst and classical karst examples from the dinarics krk island northern adriatic croatia abstract in order to contribute to the debate on the role of fluvial erosion in the shaping of karst two nearby areas with different karstic landscapes were compared areas a and b are located relatively close to each other on the southern side of the krk island adriatic sea croatia both areas are composed of similar limestone with a very high caco 3 content area a is a typical doline or polygonal type classical of karst with numerous dolines up to 57 km 2 covered with terra rossa red soil and mediterranean maquis shrubland dolines are located in zones which correspond to the strike of the main geological structures dry karstic valleys are visible only on gently inclined coastal slopes bordering the karstic plateau in contrast area b is typical of a bare karst landscape with a strong palaeo fluvial imprint the dolines are absent and the bedrock is only sporadically covered with terra rossa palaeogene marls have been observed in a few elongated depressions and in the coastal zone of area b along steep coastal slopes valleys up to 460 m km 2 are cut into the carbonates the traces of episodic surface flows are visible in some of these valleys in contrast to the valleys in area a remnants of a disrupted ancient fluvial network are clearly visible on the elevated karstic plateau in area b differences in the recent morphology are attributed mainly to varying thicknesses of the palaeogene impermeable marly cover and the intensity of tectonics in the two areas

sedimentary pyrite formation an update sedimentary pyrite formation during early diagenesis is a major process for controlling the oxygen level of the atmosphere and the sulfate concentration in seawater over geologic time the amount of pyrite that may form in a sediment is limited by the rates of supply of decomposable organic matter dissolved sulfate and reactive detrital iron minerals organic matter appears to be the major control on pyrite formation in normal non euxinic terrigenous marine sediments where dissolved sulfate and iron minerals are abundant by contrast pyrite formation in non marine freshwater sediments is severely limited by low concentrations of sulfate and this characteristic can be used to distinguish ancient organic rich fresh water shales from marine shales under marine euxinic conditions sufficient h2s is produced that the dominant control on pyrite formation is the availability of reactive iron minerals calculations based on a sulfur isotope model indicate that over phanerozoic time the worldwide average organic carbon to pyrite sulfur ratio of sedimentary rocks has varied considerably high cs ratios during permo carboniferous time can be explained by a shift of major organic deposition from the oceans to the land which resulted in the formation of vast coal swamps at that time low cs ratios compared to today during the early paleozoic can be explained in terms of a greater abundance of euxinic basins combined with deposition of a more reactive type of organic matter in the remaining oxygenated portions of the ocean the latter could have been due to lower oceanic oxygen levels and or a lack of transportation of refractory terrestrial organic matter to the marine environment due to the absence of vascular land plants at that time

classification of huminite iccp system 1994 abstract in the new classification iccp system 1994 the maceral group huminite has been revised from the previous classification iccp 1971 int handbook coal petr suppl to 2nd ed to accommodate the nomenclature to changes in the other maceral groups especially the changes in the vitrinite classification iccp 1998 the new vitrinite classification iccp system 1994 fuel 77 349 358 the vitrinite and huminite systems have been correlated so that down to the level of sub maceral groups the two systems can be used in parallel at the level of macerals and for finer classifications the analyst now has according to the nature of the coal and the purpose of the analysis a choice of using either of the two classification systems for huminite and vitrinite this is in accordance with the new iso coal classification that covers low rank coals as well and allows for the simultaneous use of the huminite and vitrinite nomenclature for low rank coals

recent developments in surface and subsurface karst geomorphology an introduction abstract where dissolution processes of bedrock dominate peculiar morphologies develop and overrule all landforms controlled by other surface processes pure karst landscapes are present in many parts of the world but most of the time landscapes are shaped by a multitude of processes the comprehension of the dissolution processes that act both at the surface and underground has developed rapidly in the last half century although major achievements had already been reached at the end of the xixth century this special issue gives an overview of some of the most recent developments in surface and subsurface karst geomorphology and reviews where further studies should be fostered

structural tectonic controls and geomorphology of the karst corridors in alpine limestone ridges southern carpathians romania abstract the relationship between surface karst development and the geological frame is widely acknowledged in the study of karst landforms it is of considerable interest especially in alpine environments e g alpine dinaric carpathian orogenic system karst corridors are generally known as kluftkarren or bogaz and form by solution of limestone along a lithoclase network the v nturari a buila massif carpathians romania is a typical alpine karst ridge and a former carbonate platform of upper jurassic age in which geologically controlled karst features have been developing over a geologic timescale field research and mapping were useful in extracting geologic features joint and structure controlled karst corridors are common in the upper section of the mountain between 1600 and 1850 m first a complex system of lithoclases fissures joints and faults occurred then surface runoff or meltwater solutionally enlarged them tension fractures strike in a northeast southwest direction parallel to homoclinal limestone layers the exposed fault walls often preserve draperies and speleothem remnants further statistical analysis of joint fault and bogaz orientations has shown the close relation between the three datasets and morphometric analysis centered only on the karst corridor system results derived from the statistical analysis of orientation data show that there is a strong preferred orientation of the bogaz or bogaz like forms along the directional faults and that they commonly develop in extensional tectonically active environments additional features typical to fluviokarst are also present subterranean connections between the karst corridors and the headwalls of the pocket valleys generating headward recession both by continuous sapping of karst springs at the headwall base followed by collapses an extremely poor surface drainage network developed in the upper pavement facing southeast compared to that on the middle and lower sides

composition of modern deep sea sands from arc related basins summary petrographic and chemical examination of modern deep sea sands shows a clear distinction between active and passive plate tectonic settings among active settings sands from forearc basins of island arcs and basins from strike slip continental margins can be distinguished but those from other arc related settings overlap considerably in composition in particular sands from continental margin subduction zones and those from the backarc of island arcs appear to be indistinguishable chemically arc related sands are very close in composition to ancient greywacke sandstones for instance sodium almost always exceeds potassium thus it is not necessary for sodium to be added to sands diagenetically to make greywackes as has been suggested the influence of tectonics on the composition of sandstones has long been a central feature of sandstone petrology the geosynclinal model of global tectonics stimulated much thought on this subject probably the best known ideas are those of krynine e g 1942 subsequently such research declined but the plate model for global tectonics has produced a new wave of interest e g crook 1974 schwab 1975 potter 1978 dickinson suczek 1979 much of this work has relied on data from ancient sediments where diagenetic changes and difficulty in de ciphering the tectonic setting limit the useful ness of the conclusions much more work is needed on recent sediments to establish a base line against which ancient sediments can be compared we have previously reported valloni maynard 1981 the results of our work on the petrography of a set of recent deep sea sands from piston cores in this paper we shall com pare this petrographic information with bulk chemistry and attempt to relate these to tecto nics in arc related settings

comparison of the vulnerability of limestone karst and siliciclastic coasts example from the kvarner area ne adriatic croatia the recent shape of the coast in the kvarner area is primarily a consequence of the drowning of karst relief due to sea level rise during the holocene further sea level rise and increased storminess in this coastal area is expected in the future in order to assess coastal vulnerability two stretches of the mainland coast and the coast of four main islands in kvarner have been examined most of the coast in the kvarner area has a low risk of wave induced marine erosion and has low vulnerability to predicted sea level changes due to its rocky origin carbonate rocky coasts make up most of the coasts whereas coasts formed in siliciclastic flysch rocks are less common the largest proportion of fine grained beaches over 20 is found on rab island due to a higher presence of less resistant flysch rocks in order to develop mitigation and adaptation plans for future coastal changes an integrated coastal zone management is proposed

modelling karst geomorphology on different time scales abstract the evolution and flow in a karst aquifer is studied with numerical simulations based on the karst model karst aquifer simulation tool the aquifer consists of a three dimensional interconnected network of conduits representing fractures in the rock and a porous rock matrix representing the finer fissured system in the rock flow through the aquifer can be driven by both diffuse recharge from precipitation and localised sinking streams and the aquifer drains towards a large karst resurgence representing the base level superimposed onto the karst aquifer is a landscape which can evolve with time by small scale diffusive processes large scale river erosion and karst denudation fractures in the aquifer are enlarged with time by chemical dissolution enhancing the secondary porosity of the karst aquifer the enlargement of fractures results in a dramatic increase of the aquifer conductivity over several orders of magnitude and a change of flow patterns from an initially pore controlled to a heterogeneous fracture controlled aquifer during the evolution the water table is falling from an initially high position close to the land surface to a lower level coinciding with the actual base level two model scenarios are studied to elucidate the karst aquifer evolution in three dimensions the evolution models are then complemented by event type spring discharge modelling which can be used as a predictive tool for karst spring discharge and contaminant transport

coal as a source rock for oil a review the geological debate about whether and to what extent humic coals have sourced oil is likely to continue for some time despite some important advances in our knowledge of the processes involved it is clear that not only liptinites but also perhydrous vitrinites have the potential to generate hydrocarbon liquids in the course of natural coalification some liptinites especially alginite cutinite and suberinite contain a higher proportion of aliphatic moieties in their structure than other liptinites such as sporinite and resinite and are therefore more oil prone it is of potential value to be able to predict the several environments of deposition in which coals with high liptinite contents or containing perhydrous vitrinites may have been formed review of the distribution of oil prone coals in time and space reveals that most are jurassic tertiary with key examples from australia new zealand and indonesia methods based both on experimental simulations and the examination of naturally matured samples have been used to determine the order of generation of hydrocarbons from different macerals results are not entirely consistent among the different approaches and there is much overlap in the ranges of degradation but it seems probable that in the natural environment vitrinites begin to generate early followed by labile liptinites such as suberinite then cutinite sporinite and finally alginite petroleum potential may be determined by experimental simulation of natural coalification or inferred through various micro techniques especially fluorescence and infrared ir spectroscopy or bulk techniques such as elemental analysis and 13c nmr spectroscopy the latter three techniques enable a measure of the polymethylene component of the coal which now appears to be one of the best available approaches for determining petroleum potential no method of experimental simulation of petroleum generation from coals is without criticism and comparative results are highly variable however hydrous pyrolysis confined pyrolysis and forms of open system hydrous pyrolysis approach acceptable simulations whether and to what degree generated liquid hydrocarbons are expelled has long been the central problem in oil from coal studies the structure of vitrinite was believed until recently to contain an interconnected microporous network in which generated oil would be contained until an expulsion threshold was attained recent studies show the pores are not interconnected combined with a dynamic model of pore generation it now seems that expulsion of hydrocarbons is best explained by activated diffusion of molecules to maceral boundaries and ultimately by cleats and fractures to coal seam boundaries the main reason for poor expulsion is the adsorption of oil on the organic macromolecule which may be overcome 1 if coals are thin and interbedded with clastic sediments or 2 if the coals are very hydrogen rich and generate large quantities of oil the existence of oil in vitrinite is attested to by solvent extractions fluorescence properties and by microscopic observations of oil and bitumen experimental simulation of expulsion of oil from coals has only recently been attempted the relative timing of release of generated co2 and ch4 could have considerable importance in promoting the expulsion of liquid hydrocarbons but the mechanism is unclear as it is universally agreed that dispersed organic matter dom in some shales readily generates and expels petroleum it is curious that few consistent geochemical differences have been found between coal macerals and dom in interbedded shales unambiguous evidence of expulsion from coals is limited and in particular only a few commercial oil discoveries can be confidently correlated to coals these include upper cretaceous fruitland formation coals in the usa from which oil is produced new zealand tertiary coals and middle jurassic coals from the danish north sea it is likely that coals have at least contributed to significant oil discoveries in the gippsland basin australia in the turpan basin china and in the kutei and ardjuna basins in indonesia but this remains unproven early reports that early jurassic coals in mid norway were a major source of the reservoired oils have been shown to be inaccurate none of the proposed rules of thumb for generation or expulsion of petroleum from coals seem particularly robust decisions on whether a particular coal is likely to have been an active source for oil should consider all available geological and geochemical information the assumptions made in computational models should be well understood as it is likely with new understandings of processes involved that some of these assumptions will be difficult to sustain

the character and origin of lacustrine source rocks in the lower cretaceous synrift section congo basin west africa lower cretaceous synrift lacustrine shales from the congo basin west africa have been analyzed with sedimentological and geochemical techniques to characterize source rock quality and identify triggers for deposition of intervals richest in organic carbon the sequence includes a lower active rift section deposited during active faulting and subsidence overlain by an upper late rift section deposited during reduced faulting and subsidence total organic carbon toc averages 2 3 wt throughout the active rift siliciclastic shale section 6 in marls in the lower part of the late rift section and 1 2 in deltaic shales in the upper part of the late rift section organic matter consists of mixed types i and iii kerogen in the active rift shales pure type i kerogen in the late rift marls and a type i and iii mixture in the late rift deltaic shales redox proxies indicate that the deep lake was relatively reducing throughout deposition of the active rift and lower late rift sections therefore enhanced anoxia did not trigger deposition of the richest source rocks decreased sedimentation rates in the late rift do not account for the full increase in toc nor the shift on organic matter type the richest source rocks are associated with high rates of organic productivity and chemical sedimentation indicating that flux of dissolved components to the rift lake including nutrients for algae growth was critical we propose that reduced topography associated with the late rift was necessary for efficient cycling of plant derived carbon into soil carbonate and ultimately the rift lake and for enhancing chemical weathering and nutrient flux

structural evolution of malay basin its link to sunda block tectonics abstract the malay basin is located offshore west malaysia in the south china sea within north central region of 1st order sunda block the basin developed partly as a result of tectonic collisions and strike slip shear of the southeast asia continental slabs as the indian plate collided into eurasia and subsequent extrusion of lithospheric blocks towards indochina the sunda block epicontinental earliest rift margins were manifested by the palaeogene w e rift valleys which formed during nw se sinistral shear of the region later eocene nw se dextral shear of 2nd order indochina block against east malaya block rifted open a 3rd order malay basin developed within it is a series of 4th order n s en echelon ridges and grabens the grabens and some ridges sequentially host w e trending 5th order folds of later compressional episodes the malay basin ridge and graben model explains the multi phased structural deformation which started with the a pre rift palaeo mesozoic crystalline metamorphic basement b synrift phase during paleogene c fast subsidence from late oligocene to middle miocene d compressional inversion of first sunda fold during late miocene and e basin sag during plio pleistocene with mild compressional episodes the subsequent mio pliocene folding history of malay basin is connected to the collision of sunda block against subducting indian australian plate this neogene sunda tectonics to some degree after the cessation of south china sea spreading is due to the diachronous collision along the 1st order plate margins between se asia and australia

isotopic biogeochemistry of the neocomian lacustrine and upper aptian marine evaporitic sediments of the potiguar basin northeastern brazil abstract systematic variations in the abundances of 13c in kerogens and in saturated hydrocarbons were used to assess the paleoenvironments of the neocomian lacustrine and aptian lagoonal to restricted marine evaporitic sediments of the pendencia and alagamar formations respectively from the potiguar basin brazil in the pendencia formation the isotopic compositions of compounds formed in the photic zone i e pristane carotane and some of the n alkanes vary only slightly with depth suggesting invariable conditions in the surface environment however dramatic changes occur in the carbon isotopic compositions of hopanoid biomarkers produced by organisms inhabiting the lower part of the water column of the pendencia paleolake parts of the section having finely laminated sediments with no burrowing coincide with the most significant 13c depletion of the hopanoids relative to algal products indicating effective stratification of the water column and active recycling of methane in the alagamar formation isotopic compositions of the n alkanes vary systematically with depth but not with carbon number indicating dominance of a single source for all n alkanes independent of carbon number and secular variations in the isotopic composition of that source the latter variations can be correlated with global changes in the isotopic composition of marine dissolved inorganic carbon associated with the oceanic anoxic event that occurred in the upper aptian oae 1 arthur m a and schlanger s o 1979 aapg bull 63 870 885 the 17 h 21 h c30 hopane is the most depleted in 13c among the compounds and reflects contributions from chemoautotrophs and in extreme cases from methanotrophs the covariations between the 13c values of pristane and phytane and these acyclic isoprenoids and carotane suggest a common origin from phytoplankton gammacerane has 13c values compatible with a derivation from bacterivorous ciliates feeding on algae and cyanobacteria growing under variable paleoenvironmental conditions

organic geochemistry and depositional environment of the aptian bituminous limestone in the kale gumushane area ne turkey an example of lacustrine deposits on the platform carbonate sequence the jurassic lower cretaceous aged carbonate sequence is widely exposed in the southern zone of eastern pontides aptian black bituminous limestone is found in the upper part of this sequence in the kale area gumushane this limestone contains faunal remains e g gastropod ostracod characean stems and miliolid type benthic foraminifera that indicate a freshwater lacustrine depositional environment the total organic carbon toc values of the bituminous limestone samples range from 0 11 1 30 with an average toc value of 0 54 the hydrogen index hi varies from 119 448 mg hc g toc average hi 298 mg hc g toc indicating that the limestone contains gas prone as well as oil prone organic matter pyrolysis data prove that the organic matter content in the bituminous limestone consists of type ii kerogen the average tmax value for bituminous limestone samples is 438 c 434 448 c bitumen toc ratios for bituminous limestone are 0 05 and 0 04 the tmax values and the ratios indicate that the bituminous limestone samples contain early mature to mature organic matter analysis of solvent extracts from the two richest bituminous limestones show a predominance of high carbon number c26 c30 n alkanes the pr ph ratio and cpi value are 1 34 and 0 96 respectively c29 is the dominant sterane with c29 c27 c28 the bituminous limestone samples have low c22 c21 ratios high c24 c23 tricyclic terpane ratios and very low c31r c30 hopane ratios 0 25 these data are consistent with the bituminous limestones being deposited in a lacustrine environment

organic geochemical characteristics and depositional setting of paleogene oil shale mudstone and sandstone from onshore penyu basin chenor pahang malaysia abstract the eastern chenor pahang area of the penyu basin contains an untapped potential in part due to poor knowledge of its organic facies characteristics the sedimentary succession of eastern chenor pahang area is dominated by fine to coarse grained sandstone occurring in association with oil shale and mudstone in a predominantly fining upward sequence detailed geochemical and petrographic characterization was carried out on oil shale and mudstone samples to evaluate the origin and type of organic matter om as well as the paleoenvironmental conditions and organic richness of the paleogene sedimentary succession the facies are only enriched in total organic carbon toc potential hydrocarbon yield s2 and extractible organic matter eom the types of organic matter are important index reflecting the potential of the source rock s based on elemental ratios the analyzed samples are shown to contain types i and ii kerogens this finding is supported by the high hydrogen index hi of 300 mg hc g toc and the presence of abundant liptinitic materials biomarker signatures n alkanes n c25 high c29 c30 17 h hopane ratios 0 8 3 3 and high c29 steranes 49 78 low total sulfur and v v ni ratio suggest a predominantly terrestrial source input with some contribution from aquatic microorganisms as indicated by the common occurrence of amorphous organic matter combining this results with n alkane patterns kerogen types and organic petrography predominance of c29 sterane probably indicates a contribution of aquatic organisms such as green and brown algae consistent with botrycoccus braunii race a and pediastrum contribution and some influence of higher plants om integration of biomarker studies with bulk geochemical and petrographic analysis suggests that the analyzed samples were deposited under suboxic conditions in a fresh water lacustrine environment this finding is corroborated by the ratios of pristane phytane v ni and sr br high bioproductivity and a stratified fresh water column with suboxic bottom water condition enhanced om preservation in the analyzed mudstone and shale facies the high om content in these samples maybe related to the fine grained matrix of the mud rocks and the paleoclimate in the area

oil shale formation in the upper cretaceous nenjiang formation of the songliao basin ne china implications from organic and inorganic geochemical analyses abstract two oil shale layers are present in the upper cretaceous nenjiang formation of the songliao basin representing excellent hydrocarbon source rocks their biomarker compositions provide evidence for a major contribution by aquatic organisms within the photic zone of the water column phytoplankton blooms were promoted by warm humid climate and lake eutrophication salinity stratification and anoxic bottom water conditions are indicated in the lower oil shale layer whereas decreased salinity and partial oxygenation of the water column are evident in the upper oil shale layer moreover an increase in sizes of alginite from the lower to the upper oil shale layer and enhanced telalginite concentrations is detected therefore a stratified water column with high salinity and anoxic bottom water conditions contributes to organic matter om preservation in the lower oil shale layer in contrast high bioproductivity in combination with om preservation favored by enhanced algae sizes and telalginite concentrations are suggested as the om enrichment mechanisms in the upper oil shale layer in addition factors such as clay minerals microbial activity and detrital matter input cannot be ignored for their influence on om enrichment in this study a preservation model within the lower oil shale layer and a productivity model within the upper oil shale layer are established the models imply that excellent preservation is the major controlling factor for om enrichment in the lower oil shale layer whereas the high bioproductivity is the major controlling factor for om enrichment in the upper oil shale layer however the combination of both factors for oil shale deposition must be considered

impacts of paleohydrological changes on n alkane biomarker compositions of a holocene peat sequence in the eastern european russian arctic coupled analyses of n alkane biomarkers and plant macrofossils from a peat plateau deposit in the northeast european russian arctic were carried out to assess the effects of past hydrology on the m

source rock characteristics of the lower cretaceous abu gabra formation in the muglad basin sudan and its relevance to oil generation studies organic rich shale and claystone are present within the lower cretaceous abu gabra formation of the muglad basin representing excellent oil source rocks the source rock potential of abu gabra organicrich whole rock samples from two oilfields in the muglad basin was investigated using bulk and quantitative pyrolysis techniques the analytical program included toc pyrolysis sra pyrolysis gc bulk kinetics elemental analysis and kerogen microscopy the results were used to characterize the kerogen composition and type of petroleum generated from these abu gabra organic rich sediments to clarify the structural variability of the organic matter in the abu gabra source rock the investigated abu gabra organic rich sediments proved to contain excellent quality lacustrine kerogens the samples have moderate to high hydrogen index hi values 267e837 mg hc g rock consistent with predominantly oil prone types i and ii kerogen with a minor contribution of type iieiii kerogens this is supported by the abundant liptinitic materials i e lipid rich structured algae structureless amorphous alginite and sporinite and high atomic hydrogen to carbon h c ratio however pyrolysis gc analysis proved that all the investigated abu gabra samples contain homogeneous type i kerogen that produces mainly waxy oil bulk kinetic experiments on these samples indicate that the source rock facies derived from a homogenous organic matter spans an extremely narrow distribution of activation energy ea ranges from 49 kcal mol to 51 kcal mol the magnitude order of frequency factors a also show a narrow distribution range from 10

geomorphological significance of the palaeodrainage network on a karst plateau the una korana plateau dinaric karst croatia abstract karst plateaus often have a complex geological and geomorphological history it is widely accepted that their development requires a long period of karst denudation this study reconstructs the palaeodrainage network of a karst plateau analyses its properties and establishes its geomorphological significance the main purpose of this research was to deepen our understanding of a key stage in the evolution of karst plateaus the transition from a fluvial land surface to one dominated by karst surface processes the study was conducted on a large part of the una korana plateau the largest plateau in the dinaric karst the majority of the plateau is made of carbonate rocks of triassic jurassic and cretaceous age that set the conditions for the development of the karst we have reconstructed the palaeodrainage network based on 1 25 000 topographic maps with 10 m contours the transition of the surface drainage network to the underground karst drainage network is still in progress so depending on the degree of karstification the drainage network was divided into three categories active dry and relict it was found that 90 5 of the pre existing drainage network has undergone some degree of karstification the active surface drainage network gradually shifted to a dry network then to a relict network the surface drainage network is gradually replaced by a dense network of dolines today the flat and karstified inter fluvial area is drained underground towards the main watercourses and these drain the entire region over the surface towards the pannonian basin this is the largest known karst palaeodrainage network in the dinaric karst that has been reconstructed in this way

morphometric properties of dolines in matarsko podolje sw slovenia matarsko podolje in sw slovenia is a karstic surface with many dolines which appear between the flysch composed brkini hills in the ne and mt slavnik in the sw we have analyzed dolines to find the morphometric parameters of the depth area volume and circularity index and also calculated the doline density and pitting index all parameters were also calculated separately for individual lithological units to explain the variations of the calculated values among these groups morphometry was performed in gis environment on a 1 1 m digital elevation model with bare earth obtained by lidar the results show a high density of dolines 94 dolines km2 and also a high pitting index rp 8 27 compared to other studies there are some significant differences between the measured values in individual lithologies as the depths areas and volumes are largest in dolomitic beds other beds include various types of limestones and carbonate breccia the median values of depth area and volume are 2 98 m 541 m2 and 690 m3 the circularity index is also lowest in dolomite beds and kozina limestones however the differences are not so pronounced as for areas and volumes dolines longer axes are parallel to the directions of major structural elements however more detailed mapping should be done to confirm the influence of faults and fracture zones on the doline geometry

tidal notches in vinodol channel and bakar bay ne adriatic sea indicators of recent tectonics abstract detailed mapping of coastline in vinodol channel and adjacent bays in the kvarner area northern adriatic sea revealed the existence of well expressed submerged notches ranging in their elevation from 45 to 115 cm below mean sea level noticeable difference in the height of these presumably coeval tidal notches is attributed to neotectonic movements since the roman times the difference of 0 1 m on opposite parts of vinodol channel is in accordance with the presumed thrusting tectonics in the adjacent vinodol valley the deeper position of coeval tidal notches in bakar bay the drowned part of vinodol valley indicates it is the tectonically most active zone investigation of tidal notches in this case complements information from the solid rock geology and measurements of recent tectonic movements revealed by gps positioning moreover it indicates the potential of detailed mapping of tidal notches for neotectonic research in some coastal areas

a review of possible eustatic isostatic and tectonic contributions in eight late holocene relative sea level histories from the mediterranean area abstract this paper consists of a comparison between eight late holocene sea level histories investigated by the author in different mediterranean areas and sea level predictions in the same areas made by global isostatic models the areas include three regions that are generally considered as tectonically relatively stable 1 the southern coast of france 2 sardinia and 3 the southern coasts of tunisia where late holocene evidence may be either of submergence or of emergence also considered are 4 a subsidence region in the northern adriatic and actively uplifting areas 5 in calabria and 6 in nisyros island greece lastly case studies in areas affected by repeated coseismic vertical displacements include 7 western crete and antikythira island in the hellenic arc and 8 the levant coasts of turkey syria and the lebanon in each case the question of whether the evidence available may or may not be consistent with gradual isostatic or eustatic displacements has been explored it appears that in non tectonic areas the hydro isostatic effects have been overestimated sardinia or underestimated southern tunisia by the same models in the northern adriatic the closest mediterranean area to the former scandinavian ice sheet glacio eustatic effects are suspected to be almost absent our analysis failed to quantify isostatic effects in areas of rapid tectonic uplift calabria and nisyros but rejected predictions of significant isostatic subsidence in the hellenic arc and on the levant coast finally several data from tectonic and non tectonic areas are consistent with nearly stable global eustasy since 6000 bp thus challenging the assertion of significant additional melting of antarctica after the complete melting of the former northern hemisphere ice caps

organic geochemistry and elements distribution in dahuangshan oil shale southern junggar basin origin of organic matter and depositional environment abstract the dahuangshan oil shale located in the northern bogda mountain on the southern margin of the junggar basin was deposited in a late permian lacustrine environment a combined investigation of element and organic geochemistry was performed to define the source rock potential the paleoenvironment and source of the organic matter thick sequences of oil shales with an average thickness of 638 m were deposited in lucaogou formation which mainly consists of oil shale argillaceous dolomite silty claystone tuff limestone and dolomitic marl a spot of plant stem fossils and abundance of pyrite crystals fishtail and fish skeleton can also be found there analyzed oil shale samples from dahuangshan area are characterized by high total organic carbon toc contents 5 6 34 75 s2 22 65 199 25 mg hc g rock hydrogen index hi 359 1068 mg hc g toc and oil yield 4 9 26 6 indicating the oil shales have excellent source rock potential tmax values 433 453 c show an early to medium maturation stage of organic matter which is supported by organic geochemical maturation parameters all of the obtained kerogen types are types ii and i with oil prone source rock potential dahuangshan oil shale samples are rich in sio2 68 59 followed by al2o3 10 18 and fe2o3 5 43 compared with average shale and north american shale composite nasc analyzed oil shale samples are obviously enriched in p 0 71 there is a significant correlation between al2o3 and fe2o3 mgo k2o mno cu ba co and ni for their association with clay minerals besides the significant correlations between fe2o3 and mno co and ni are considered to result from their similarity on geochemical behavior all selected oil shales are characterized by distinctly sloping light rare earth elements lree trends lan smn 2 70 5 95 accompanied by flat heavy rare earth elements hree trends with distinct eu negative anomalies 0 60 0 73 two slightly different patterns of rees in the oil shale samples are distinguished by the difference in ce depletion and nd anomaly in addition dahuangshan oil shale samples are characterized by short to middle chain n alkanes low carbon preference index cpi values 0 93 1 24 single peak composed of nc20 or nc22 low pr ph 0 41 0 91 relatively high homohop index 0 061 0 99 and high concentrations of c27 sterane indicating reducing deep water and moderate saline environment with prevalent contribution of algae and microorganisms to organic matter accumulation

organic petrological and organic geochemical characterisation of the tertiary coal bearing sequence of batu arang selangor malaysia abstract the tertiary coal bearing sequence at batu arang in selangor peninsular malaysia consists of a sandstone coal oil shale facies assemblage a detailed organic petrological and organic geochemical study was carried out on several organic rich sediments from this sequence the oil shales are dominated by botryococcus derived telalginite and pediastrum derived lamalginite the coals hypautochthonous in origin are mainly duroclarite type although other minor microlithotypes also occur alginite is not observed in the coals but other liptinitic constituents are very common particularly thin walled cutinite and sporinite the oil shales and the coals are thermally immature this immaturity has a considerable influence on the biomarker distributions particularly so on the triterpanes which are dominated by c 31 22r and c 30 compounds interestingly for tertiary aged sediments of continental origin the diagnostic biomarker compounds such as 18 h oleanane and bicadinanes normally linked to the higher land plant group of angiosperms are not observed in the samples analysed tricyclic terpanes occur only in very low relative abundance or are virtually absent a clear distinction however in the biomarker distributions of the shales and the coals carbargilite can be made based upon the distribution of c 27 c 29 regular steranes the shales with a source input being predominantly planktonic algae are dominated by 5 h 14 h 17 h 20r cholestane while the coals carbargilites with a source input consisting mainly of higher plant material are dominated by 5 h 14 h 17 h 20r ethyl cholestane the depositional environment of the batu arang coal bearing sequence is interpreted as varying from an alluvial flood plain peat swamp to fluvio lacustrine depositional setting

provenance and tectonic setting of late carboniferous clastic rocks in west junggar xinjiang china a case from the hala alat mountains abstract the late carboniferous palaeo tectonic setting of the west junggar region is comprised of arcs alternating with basins geochemical analysis of the sedimentary rocks associated with these arc related basins was conducted to better constrain the provenance and tectonic setting major and trace element geochemistry data of late carboniferous mudstones and sandstones in the hala alat mountains suggest that these sedimentary rocks and their source areas are characterized by the following four features 1 sediments experienced a simple recycling process 2 a low degree weathering conditions in the source areas 3 compositional immature of the sedimentary rocks 4 dominated by intermediate to felsic provenance with a few intermediate to mafic sediments integrated with the palaeo flow data and previous authors works a fore arc basin model is proposed for the tectonic setting of the sedimentary rocks the sawur arc is the primary provenance and supplies the major intermediate to felsic detrital fragments the bozchekul chingiz arc and kexia oceanic island arc are the other two secondary sources

gis based analysis of doline density on taurus mountains turkey the taurus mountain is one of the most important karstic region of the world and dolines are characteristics landforms of this area however the number and distribution of doline are unknown in the study area the aims of this study are to explain the total number of dolines distribution of doline density effects of slope conditions and the change of doline orientation in the taurus mountains according to the 1 25000 scale topographic maps utilized in this study a total of 140 070 dolines were determined in a 13 189 km2 area on eleven high karstic plateaus bordered by steep slopes and deep gorges these plateaus are substantially affected by highly faulted and jointed systems and about 80 of each plateau is covered with neritic limestone the dolines are located at an elevation between 10 and 2870 m average elevation of all dolines is 1842 m 90 of dolines are located between 1300 and 2270 m and only 5 of dolines found under 1330 m according to this results the densest doline zone corresponds to the alpine and periglacial zone above the treeline doline density reaches 100 doline km2 on mt anamas and the seyran geyik and akdag ranges as well as the taseli plateau maximum density 187 doline km2 is found on the akdag mountains however 66 of the study area is characterized by low density 29 9 with moderate density 3 4 with high density and 0 7 with very high density the highest doline densities are seen on gentle slopes 15 25 km2 and steep slopes 35 km2 are limited doline distribution according to the rose diagram formed by the azimuths of the long axis of the dolines at the central taurus two direction are dominant in doline orientations nw se and ne sw however dominant directions are ne sw at eastern ne sw and nw se at central and nw se at western part of the central taurus according to this elongations doline orientations are formed an arc which is formed by tectonic evolution of the central taurus

late pleistocene holocene sea level rise and the pattern of coastal karst inundation records from submerged speleothems along the eastern adriatic coast croatia in order to reconstruct the late pleistocene holocene sea level rise along the eastern adriatic coast eight speleothems were collected from three submerged caves along the croatian coast from depths of 38 5 to 17 m the marine biogenic overgrowth layer and the youngest and the oldest parts of the speleothems were dated by the 14c method their stable isotope 13c 12c and 18o 16o contents were also measured from the measured 14c activity of the marine overgrowth and using the model of alessio et al 1992 risultati preliminari relativi alla datazione di speleotemi sommersi nelle fasce costiere del tirreno centrale giornale di geologia ser 3 54 2 165 193 the start of overgrowth i e the time of flooding by seawater was determined to be 10 185 cal bp at 36 m 9160 cal bp at 34 m and 7920 cal bp at 23 m our results partially match the sea level curves reconstructed for adjacent areas tyrrhenian coast and french mediterranean coast however the start of the marine overgrowth on speleothems in pit caves indicates strong dependence on the steepness of the terrain on steep extensively karstified coasts marine overgrowths on speleothems coincided with the submersion of the speleothems due to the relatively short distance between the pit and the open sea and fast penetration of seawater into the pit in contrast marine overgrowths on speleothems in pits in the flat terrains occurred later because speleothem growth ceased due to flooding with fresh groundwater later the fresh water was replaced by seawater due to the greater distance of the inland pits to the former coast

the role of loamy sediment terra rossa in the context of steady state karst surface lowering abstract reddish loamy material terra rossa found on many karstified surfaces has long been accepted as a characteristic karst feature two basic views of terra rossa formation were distinguished related to either a residual or a detrital origin more recently it has been suggested that it could derive from isovolumetric reactions between the parent carbonate rock and airborne material this paper reviews possible sources of terra rossa explores its behaviour on the karst surface from the karst geomorphology viewpoint and considers whether its existence is better explained in terms of a closed or open karst geomorphic system two approximately west east traverses were laid out across slovenia and the czech republic comprising nine sample locations in each country previously known to be characterized by terra rossa general geomorphic speleomorphic conditions were estimated and loamy material and parent rock samples were collected insoluble residues extracted from the rock were processed in the same ways as the loamy material basic geochemical and mineralogical investigations were run the data obtained were processed statistically results show that statistical relationships between the adjacent rock insoluble residues and adjacent terra rossa bodies exist only at sampling sites recognised as vertical most such sites are cutters which are karren like grooves formed beneath the soil more commonly referred to as subsoil karren us environmental protection agency 2002 a lexicon of cave and karst terminology field m s ed p 53 possible sources of terra rossa material as well as the possibilities of material accumulating on the karst surface are discussed in detail with special emphasis upon cutters theoretical considerations indicate that cutters are the only features that can collect sufficient insoluble residue to be detectable after a period of evolution within a surface that is lowering under steady state conditions all other accumulations of similar appearance must be admixed materials of diverse origins or be completely allogenic in origin the most recent approach which considers terra rossa as an active karst surface agent is temporarily put aside though its explanatory potential in the future is acknowledged

the origin type and preservation of organic matter of the barremian aptian organic rich shales in the muglad basin southern sudan and their relation to paleoenvironmental and paleoclimate conditions barremianeaptian organic rich shales from abu gabra formation in the muglad basin were analysed using geochemical and petrographic analyses these analyses were used to define the origin type of organic matters and the influencing factors of diagenesis including organic matter input and preservation and their relation to paleoenvironmental and paleoclimate conditions the bulk geochemical characteristics indicated that the organic rich shales were deposited in a lacustrine environment with seawater influence under suboxic conditions their pyrolysis hydrogen index hi data provide evidence for a major contribution by type i ii kerogen with hi values of 400 mg hc g toc and a minor type ii iii contribution with hi values 400 mg hc g toc this is confirmed by kerogen microscopy whereby the kerogen is characterized by large amounts of structured algae botryococcus and structureless amorphous with a minor terrigenous organic matter input an enhanced biological productivity within the photic zone of the water columns is also detected the increased biological productivity in the organicrich shales may be related to enhanced semi arid humid to humid warm climate conditions therefore a high bio productivity in combination with good organic matter preservation favoured by enhanced algae

coal bearing strata of labuan mode of occurrences organic petrographic characteristics and stratigraphic associations the current study describes the mode of occurrences of labuan cenozoic coals as observed in the field and identifies the coal macerals based on their organic petrographic characteristics as observed under reflected white light and blue light excitation in this study some sedimentological aspects such as the depositional environment were correlated with the organic petrological characteristics of the coals based on the organic petrographic features and the thermal maturity as determined by vitrinite reflectance some new stratigraphic associations have been identified similarities in sedimentological and organic petrological characteristics suggest that the shaly strata associated with carbonaceous sandstones exposed on the north western part of labuan island and the outcrop exposed in the south within the east kiam sam peninsula belong to the same sequence within the setap shale formation based on petrographic characteristics described and vitrinite reflectance values obtained from this study at least four distinct units that are associated with coal bearing sediments can be recognized strata with vitrinite reflectance vr ro in the range of approximately 0 4 0 5 is the youngest and belongs to the belait formation which include the tg layang layangan unit the oldest sequence outcropping at tg punei near the labuan crude oil terminal shell terminal belongs to the west crocker formation possesses vitrinite reflectance in the range of 0 8 0 9 whereas the intermediate unit is the setap shale formation which possesses vr of 0 55 0 6 including the east kiam sam sandstone unit and temburong formation which possesses vr in the range of 0 65 0 75 it ought to be noted that the differences in the thermal maturity variations within the cenozoic sediments of labuan reported here does not form the fundamental basis of the stratigraphic subdivision of labuan but an attempt to associate it with what appear to be the still unresolved stratigraphic issues of labuan these vr values suggest the belait formation is immature setap shale formation is early mature while the temburong and west crocker formations are at peak maturity for liquid hydrocarbon generation the analysed coals are predominantly mangrove derived and considered to be oil prone as suggested by the common occurrences of oil haze suberinite bituminite exsudatinite and perhydrous vitrinite

carbon sulfur iron relationships and δ13c of organic matter for late albian sedimentary rocks from the north atlantic ocean paleoceanographic implications abstract cores from six deep sea drilling project sites 367 369 137 386 387 and 603 of the late albian north atlantic ocean were investigated for organic carbon content 13c values of the kerogens maceral composition of the organic matter c s ratios fe toc s relationships and framboidal pyrite size distribution in order to evaluate processes that led to the accumulation of organic matter rich black shale deposits the results show a clear separation of the albian north atlantic into an anoxic eastern part and a mostly oxic western part the eastern north atlantic is dominated by organic matter rich deposits sulfate reduction occurred in an oxygen free water column and resulted in characteristic c s ratios fe toc s relationships and framboidal pyrite size distribution patterns elevated productivity anoxia and high sedimentation rates supported the formation of black shale deposits for most of the western and central parts organic matter sedimentation took place through an oxygenated water column the accumulated organic matter is dominantly of terrigenous origin the deposition of marine derived organic matter was most likely controlled by productivity paleobathymetry and low sedimentation rates

bottom water oxygenation history in southeastern arabian sea during the past 140 ka results from redox sensitive elements the concentrations of multiple redox sensitive elements such as re u mo cd v sb and tl were determined in sediments from the southeastern arabian sea 9 o 21 n 71 o 59 e to understand the bottom water oxygenation history throughout the past 140 ka the enrichment of redox sensitive elements re u cd and sb above average crustal abundances suggests that the last glacial maxima 17 48 ka stadials of marine isotope stage mis 5 5b and 5d and glacial termination gt ii 133 ka were associated with suboxic bottom water conditions sediments deposited during these suboxic conditions show the highest re content up to 54 ppb normalized to a carbonate free basis which is highly enriched over average continental crust 0 4ppb and these sediments appear to be the major sink for the global mass balance estimation marine isotope stages 1 3 4 and interstadials of mis 5 5a 5c 5e were all associated with near oxic conditions overall the lack of enrichment of mo and v above crustal abundance and a high re mo ppm ppm ratio avg 18 2x10 3 suggest that sediments of the southeastern arabian sea never contained free h2s during the last 140 ka these changes in the bottom water oxygen content can be related to the oceanic circulation pattern during this time and in part are reflected in relationships between the timing of redox changes and paleoproductivity proxies

historical contingency in fluviokarst landscape evolution abstract lateral and vertical erosion at meander bends in the kentucky river gorge area has created a series of strath terraces on the interior of incised meander bends these represent a chronosequence of fluviokarst landscape evolution from the youngest valley side transition zone near the valley bottom to the oldest upland surface this five part chronosequence not including the active river channel and floodplain was analyzed in terms of the landforms that occur at each stage or surface these include dolines uvalas karst valleys pocket valleys unincised channels incised channels and cliffs smaller features such as swallets and shafts also occur landform coincidence analysis shows higher coincidence indices ci than would be expected based on an idealized chronosequence ci values indicate genetic relationships common causality among some landforms and unexpected persistence of some features on older surfaces the idealized and two observed chronosequences were also represented as graphs and analyzed using algebraic graph theory the two field sites yielded graphs more complex and with less historical contingency than the idealized sequence indeed some of the spectral graph measures for the field sites more closely approximate a purely hypothetical no historical contingency benchmark graph the deviations of observations from the idealized expectations and the high levels of graph complexity both point to potential transitions among landform types as being the dominant phenomenon rather than canalization along a particular evolutionary pathway as the base level of both the fluvial and karst landforms is lowered as the meanders expand both fluvial and karst denudation are rejuvenated and landform transitions remain active

stability of detrital heavy minerals on the norwegian continental shelf as a function of depth and temperature abstract petrographic analysis of 1931 thin sections from sandstones of pliocene to devonian age on the norwegian continental shelf indicate that the heavy minerals zircon tourmaline rutile apatite and spinel survive to depths exceeding 5000 m and to temperatures of around 200 c without showing signs of intrastratal dissolution on the other hand the maximum depth and temperature of occurrence for amphibole are 841 m and 40 c around 1500 m and 55 c for sphene when 0 5 km of probable uplift is taken into account 2231 m and 92 c for kyanite 2559 m and 95 c for epidote 2810 m and 109 c for staurolite and 4589 m and 175 c for garnet initial signs of garnet dissolution occur at around 2000 m depth and all garnets are partially dissolved at depths greater than 3500 m monazite is present down to 4858 m and 182 c and chloritoid to 3811 m and 149 c it is however uncertain whether this is due to the low number of samples deeper than 4858 m and to the rare occurrence of chloritoid or to intrastratal dissolution the same sequence of heavy mineral stability is found when volume of quartz cement is used as a proxy for time temperature exposure quartz cement is not found in samples containing amphibole or detrital sphene a maximum of a fraction of a percent quartz cement is found in samples containing kyanite up to 1 together with epidote up to 6 with staurolite up to 24 with chloritoid up to 25 with garnet whereas maximum values of 25 35 are present together with zircon tourmaline rutile patite spinel and monazite the sequence of persistence of heavy minerals versus depth found in this study is very similar to results from several previous studies although unstable heavy minerals survive to greater depths in very young and rapidly buried sandstones and there are some differences regarding the stability of sphene and epidote heavy mineral dissolution has created secondary pores and possibly has contributed to precipitation of kaolinite illite quartz and carbonates in the studied sandstones but these reactions are of very limited volumetric importance

trace element behavior and redox facies in core shales of upper pennsylvanian kansas type cyclothems the black shale submember of core shales of pennsylvanian kansas type cyclothems is highly enriched in redox sensitive trace elements tes relative to the overlying gray shale submember as well as to many other modern and ancient organic rich deposits controls on trace element behavior in the black shale can be inferred from trace element enrichment factors efs relative to gray shale and the relationship of tes to total organic carbon toc most tes conformed to one of two patterns 1 mo u v zn and pb exhibited moderate efs and strong covariation with toc in samples having 10 wt toc and 2 cu ni cr and co exhibited low efs and moderate to strong covariation with toc in all samples these patterns are inferred to represent different responses to benthic redox conditions the first pattern is characteristic of tes of strong euxinic affinity i e those taken up in solid solution by fe sulfide or involved in other reactions catalyzed by free h2s and resident mainly in authigenic phases whereas the second pattern is characteristic of tes of weak euxinic affinity i e those not strongly influenced by the presence of free h2s and resident mainly in the organic carbon or detrital fractions of the sediment these inferences allowed development of a multiproxy technique for assessing redox facies in black shale samples euxinic conditions were considered to have existed if at least two of four redox indicator trace elements mo u v zn showed euxinic levels of enrichment and nonsulfidic anoxic conditions were inferred otherwise the validity of the procedure is indicated by 1 agreement among all four redox indicators for a large majority of samples 69 of 185 2 among samples yielding a mixed redox signal a systematic sequence of te enrichment v zn mo u and 3 for tes of weak euxinic affinity reduced variance among samples representing each redox facies sequential enrichment may be a response to differential redox thresholds for accumulation e g v or postdepositional remobilization of trace elements e g u and may provide a basis for finer assessment of redox conditions in low oxygen paleoenvironments than permitted by simple classification schemes the multiproxy procedure for redox facies analysis developed in this study is likely to be more reliable than widely used single proxy indicators based on trace elements e g mo authigenic u or v v ni or c s fe systematics e g s toc or dop d 2004 elsevier b v all rights reserved

biomarkers and geochemical indicators of holocene environmental changes in coastal lake sarbsko poland organic rich samples from the holocene sedimentary sequence of lake sarbsko were investigated to reconstruct variations in the aquatic system in response to environmental change the aims were to i identify organic matter om sources ii examine changes in soluble om composition in relation to fluctuations in limnological conditions and iii validate the sensitivity of organic geochemical indicators in tracing environmental changes diatom frustules are abundant in all samples alginite macerals and terrigenous organic matter further contribute to the sedimentary om organic petrography total organic carbon toc n ratio values and high content of biogenic silica sio2 biogenic argue for a predominant algal source of om in contrast the n alkane distributions high relative abundance of c29 steroid hydrocarbons and high content of detrital quartz in the sediments provide evidence for the input of terrigenous material as a major om source within the basin the terpenoid biomarker composition indicates a contribution from conifers and angiosperms from the diterpenoids in the samples a contribution from species of the coniferales family pinaceae is concluded toc s and mg ca values as well as steroid hopanoid concentration ratios reflect enhanced water salinity in this coastal lake due to ingression of brackish water from the baltic sea during the atlantic and sub atlantic periods as indicated by the positive relationship between d 13 c of toc and mg ca d 13 c values are influenced by changing contribution of marine vs freshwater phytoplankton additional isotopic heterogeneity in d 13 c may result from differences in terrigenous om supply vs autochthonous om production in the lake the isotopic composition of calcites supports the establishment of freshwater conditions in the lake during the sub boreal period pristane phytane and fe mn ratios are interpreted to reflect differences in the redox conditions oxygenation of bottom waters was temporarily variable with highest levels of oxygen availability during the sub boreal freshwater lake high contents of hopanoid hydrocarbons argue for enhanced microbial activity in the water column and sediment the occurrence of 2b methyl hopanes is related to the presence of cyanobacteria or methylotrophic bacteria

evolution of the adriatic carbonate platform palaeogeography main events and depositional dynamics abstract the adriatic carbonate platform adcp is one of the largest mesozoic carbonate platforms of the perimediterranean region its deposits comprise a major part of the entire carbonate succession of the croatian karst external or outer dinarides which is very thick in places more than 8000 m and ranges in age from the middle permian or even upper carboniferous to the eocene however only deposits ranging from the top of the lower jurassic toarcian to the top of the cretaceous can be attributed to the adcp defined as an isolated palaeogeographical entity although the entire carbonate succession of the karst dinarides was deposited within carbonate platform environments there were different types of carbonate platforms located in different palaeogeographical settings carboniferous to middle triassic mixed siliciclastic carbonate deposits were accumulated along the gondwanian margin on a spacious epeiric carbonate platform after tectonic activity culminating by regional middle triassic volcanism recorded throughout adria the african promontory a huge isolated carbonate southern tethyan megaplatform abbreviated as stm was formed with the area of the future adcp located in its inner part tectonic disintegration of the megaplatform during the middle to late early jurassic resulted in the establishment of several carbonate platforms including the adriatic apenninic and apulian separated by newly drowned deeper marine areas including the adriatic basin as a connection between the ionian and belluno basins lagonero basin and the area of the slovenian and bosnian troughs the adcp was characterised by predominantly shallow marine deposition although short or long periods of emergence were numerous as a consequence of the interaction of synsedimentary tectonics and eustatic changes also several events of temporary platform drowning were recorded especially in the late cretaceous when synsedimentary tectonics became stronger leading up to the final disintegration of the adcp the thickness of deposits formed during the 125 my of the adcp s existence is variable between 3500 and 5000 m the end of adcp deposition was marked by regional emergence between the cretaceous and the palaeogene deposition during the palaeogene was mainly controlled by intense synsedimentary tectonic deformation of the former platform area some carbonates mostly eocene in age were deposited on irregular ramp type carbonate platforms surrounding newly formed flysch basins and the final uplift of the dinarides reached its maximum in the oligocene miocene the adriatic carbonate platform represents a part although a relatively large and well preserved one of the broader shallow water carbonate platform that extended from ne italy to turkey although its continuity is somewhat debatable in the area near albanian greece boundary this large carbonate body which was deformed mostly in the cenozoic including a significant reduction of its width needs a specific name and the central mediterranean carbonate platform is proposed abbreviated to cmcp although the local names such as adcp for its nw part should be kept to enable easier communication and to facilitate description of local differences in platform evolution

tectonic constraints on the late pleistocene holocene relative sea level change along the north eastern adriatic coast croatia abstract in spite of very favourable coastal features late pleistocene holocene relative sea level changes along the eastern adriatic coast are still not completely resolved mostly due to the intensive and complicated regional and local neotectonics we gathered current knowledge that generally presents the north adriatic area as subsiding one and proposed a reconstruction in new light of possible very slow local uplift average rate of 0 1 0 25 mm a for last 80 ka which is supported by well dated submerged speleothems and tectonic reconstruction in addition such a scenario supports also the formation of tidal notches that are common in the north adriatic region but not yet entirely understood however according to the latest mediterranean data on sea level during the marine isotope stage mis 5 1 being at 1 m 80 ka ago we do not dismiss the possibility of subsidence which would have been 0 18 0 23 mm a on average for the last 80 ka but notch formation under such condition would not have been realistic apparently the position of the north eastern adriatic coast on a convergence area requires extensive palaeoenvironmental studies including structural lithostratigraphical palaeontological archaeological and radiometric data and application of isostatic modelling

climatic control on the composition of carboniferous permian gondwana sediments khalaspir basin bangladesh abstract late paleozoic or permo carboniferous gondwana successions world wide are marked by widespread and lengthy glaciation 67 ma and multiple transitions from icehouse to greenhouse state mineralogical and compositional changes in sandstones and mudstones of the gondwana succession in drill hole gdh 45 from the khalaspir basin of bangladesh are interpreted in a climatic framework using the proxies of the mineralogical index of alteration mia and the chemical index of alteration cia low mia

structural controls on distribution of dolines on mount anamas taurus mountains turkey abstract solution dolines are characteristic landforms on the high plateaus of the taurus mountains in this study the effects of tectonic structures drainage and slope conditions on the distribution and morphometric properties of dolines in the western part of the central taurus are explained to delimit the dolines 1 25000 scale topographic maps were used the uppermost closed contour lines were digitized as polygons and the elevation long and short axes elongation ratios orientation angles of the polygons were calculated the doline density is compared with drainage density and mean slope values a total of 111 rose diagrams were created in order to illustrate the superficial distribution of orientation as a result a total of 10 652 dolines were detected in a 711 km2 doline area and maximum density reaches 123 dolines km2 however according to the doline density two distinct regions were detected high density r1 and low density r2 correlations between drainage density slope angle and doline density are negative in the two regions according to negative correlations the drainage density is not a determinant factor in r1 while it is a determinant factor in r2 a 30 slope angle in km2 limits doline distribution on the plateau surface the orientation of all doline long axes is nw se which is parallel to the general orographic extent of mount anamas however different orientations were detected and these orientations were showed in farther sub regions according to the 111 gridded rose diagrams the overall result of this study is that the fault and joint systems that developed on the thick bedded limestone between thrust faults affected the doline density while lateral strike slip normal faults and joint systems in front of the thrust belt were more effective on the geometric shapes of dolines

detecting and characterizing unroofed caves by ground penetrating radar abstract the bare karst surface in the southeastern part of krk island croatia is characterized by different surface karst features such as valley like shallow linear depressions and partially or fully sediment filled depressions of various shapes and sizes they were noticed due to locally increased thickness of sediment and enhanced vegetation but had not yet been systematically studied and defined considering only the geometry of the investigated surface features and the rare traces of cave environments detected by field surveys it was unclear which processes surface karstification and or speleogenesis contributed most to their formation the low frequency ground penetrating radar gpr method using a special 50 mhz rta antenna was applied to study and describe these karst features three study sites were chosen and 5 km of gpr profiles were positioned to include various surface features the results obtained from the gpr investigation lead to the following conclusions 1 an increased thickness of sediment was detected in all the investigated depressions indicating their considerable depth 2 areas between different depressions expressed as attenuated zones in gpr images reveal their interconnection 3 transitions between surface and underground features are characterized by a collapsed passage visible in the gpr data and 4 an underground continuation of surface valley like depressions was detected proving the speleogenetic origin of such features subsurface information obtained using gpr indicates that the valley like depressions irregular depressions completely or partially filled with sediment and some dolines are associated with a nearly 4 km long unroofed cave and developed as a result of karst denudation in the regional context these results suggest long lasting karstification processes in the area in contrast to the pre karstic fluvial phase previously assumed to have occurred here this research is the first application of the gpr method to survey unroofed caves worldwide and the first detailed study of such karst features in croatia the low frequency gpr proved to be an efficient method not only for detecting underground continuations but also for distinguishing and identifying surface features and transition zones between surface and subsurface segments of unroofed caves and can therefore be used for recognizing similar geomorphological features

erroneous maturity assessment given by tmax and hi rock eval parameters on highly mature weathered coals abstract two sets of mature coals have been collected at outcrop on two dipping coal seams in the ales carboniferous coalfield massif central france visual examination petrographic observations and rock eval pyrolysis studies unequivocally suggest that these coals have been weathered the intensity of this alteration increasing progressively towards the soil according to the reflectance rr values of 1 7 1 8 these coals have reached low volatile bituminous rank in contrast to the reflectance which does not exhibit any marked variation along the studied sections tmax although classically considered as a rank parameter increases progressively with decreasing distance from the surface this tmax increase is accompanied by a decrease in the hydrogen index hi and with an increase in oxygen index oi all these changes are undoubtedly consequential to weathering thus in the present case tmax must not be considered as a maturity indicator but as an oxidation parameter like oi and the o c atomic ratio this conclusion is also supported by the positive correlation between tmax and proportion of oxidised vitrinites i e bearing oxidation marks provided by maceral analysis this peculiar behaviour of tmax in response to the weathering of mature coals is in total contrast with its invariance during low mature coal alteration this finding obliges us to moderate or even to revise the conclusions of a previous work on mature coals sampled at outcrop int j coal geol 44 2000 49 where higher tmax than expected from rr values were supposed to have been necessarily caused by warm and oxidizing fluids