monoterpenylabietenoids novel biomarkers from extant and fossil taxodioideae and sedimentary rocks abstract the presence of 7 p cymenylferruginol and its diagenetic biomarkers occurring in cenozoic fossil plants and mesozoic siltstones and coals has been studied using gas chromatography mass spectrometry both 7 and 7 p cymenylferruginol isomers were the dominant natural products with two novel minor additional isomers namely 3 and 3 p cymenylferruginol and two hydrocarbons 7 and 7 p cymenyldehydroabietane the other tentatively assigned aromatic hydrocarbons were 9 10 p cymenylretene and 9 p cymenylsimonellite which were present in upper cretaceous and lower jurassic sedimentary rocks with their further dehydrogenation products diterpenoid dimers were also tentatively identified in trace amounts with 11 and 14 ferruginylferruginol as the dominant compounds our results show that the p cymenylferruginols and p cymenyldehydroabietanes are not thermally stable and that their occurrence in sedimentary rocks is controlled by the maturity of the organic matter om also chamaecydin identified for the first time in pre paleogene strata was not detectable when the om maturity based on vitrinite reflectance was higher than 0 45 0 5 rr

armoured sponge spicules from panarea island italy implications for their fossil preservation abstract a variety of calcareous and siliceous skeletal components are associated with exceptional still active deposits of modern iron ooids off panarea one of the volcanic islands of the aeolian arc tyrrhenian sea italy both ooids and skeletal components occur as loose sediments influenced by submarine hydrothermal fluid vents whereas iron ooids are exclusively made of goethite laminae primarily nucleated on volcaniclastic material sponge spicules that represent most of the siliceous skeletal component develop laminated coatings concretions of varying sizes this partial or total coating consists of regularly banded fe rich layers exhibiting the same textural features and mineralogical composition goethite of the ooid cortex developed around inorganic cores spicules did not reveal any obvious attaching structure or interfingering with the surrounding coating and did not undergo bioerosion or any other evidence of biological intervention during their development a hydrothermal origin compatible with the general setting is therefore proposed for these armoured sponge spicules we believe that this unique modern case of iron concretions produced on siliceous spicules can contribute to explain other known fossil cases as well as to understand the taphonomy of this type of biogenic silica that seems rarely to have been preserved in such an extreme habitat

chemostratigraphy of the posidonia black shale sw germany ii assessment of extent and persistence of photic zone anoxia using aryl isoprenoid distributions aquatic depositional environments where anoxic conditions extend from bottom waters into the photic zone occurred frequently during the geologic past periods of photic zone anoxia pza can be recognized by the presence of specific lipids produced exclusively by the green sulphur bacteria chlorobiaceae that are preserved in the sedimentary record chlorobiaceae perform anoxygenic photosynthesis that requires light penetration into h2s saturated waters sediment samples integrate paleoenvironmental conditions over time intervals ranging from at best a few decades to more commonly several millennia photic zone anoxia recognized in paleoenvironmental analyses is thus defined as episodic with no further interpretation on the duration and persistence of the anoxic events we provide here a high resolution multiproxy chemostratigraphy study for the toarcian posidonia black shale from the dotternhausen section in sw germany in order to assess duration and seasonal fluctuation of photic zone anoxia based on the relative abundance of derivatives of chlorobiaceae lipids we assess the variability in the degree and persistence of photic zone anoxia using an aryl isoprenoid ratio air obtained by calculating the proportion of the short chain c13 17 versus the intermediate chain c18 22 aryl isoprenoids higher relative abundance of the short chain analogues is interpreted as indicating more intensive aerobic degradation of aryl isoprenoids air varies between values of 0 5 indicative of persistent pza phases and 3 0 for short termed episodic pza events absolute concentration of aryl isoprenoids is negatively correlated with the air which is in agreement with a progressive diagenetic breakdown of aryl isoprenoids the air decreases are validated using independent palecological and geochemical redox indicators for the posidonia shale in sw germany d 2004 elsevier b v all rights reserved

dynamics of tethyan carbonate platforms tethyan carbonate platforms are relatively short lived depositional systems which were born developed died and sometime resurrected in a tectonically active area in contrast with pericratonic platforms which are generally huge in size hundreds of kilometers across and show wide facies belts very gentle slopes ramps and transitional boundaries tethyan carbonate platforms are smaller tens of kilometers and have steep slopes generally faulted boundaries and abrupt facies changes it appears clear that the overall control on these two contrasting systems is the geodynamic milieu relatively stable in the first case where eustatic oscillations and long term subsidence are probably the main dictators quite dynamic and aggressive in the second one where carbonate platforms developed through the entire geodynamic spectrum rifting transtension transpression and collision of the wilson cycle primary controls on tethyan carbonate platforms appear to be tectonics most important and eustatic sea level oscillations which determine their emplacement growth and decay their overall shape and architecture are a function of these factors secondary factors affecting tethyan carbonate platform evolution are physiography oceanographic conditions and biology as a function of geologic time especially across the mesozoic tertiary boundary facies and facies distribution and to a lesser extent their shape are controlled by thesemore variables less

middle eocene seagrass facies from apennine carbonate platforms italy abstract two stratigraphic sections located in the latium abruzzi monte porchio central apennines central italy and in the apulian carbonate platform s cesarea torre tiggiano salento southern italy were measured and sampled to document the sedimentological characteristic and the faunistic assemblages of middle eocene seagrass deposits the faunistic assemblages are dominated by porcellaneous foraminifera orbitolites alveolina idalina spiroloculina quinqueloculina triloculina and abundant hooked shaped gypsinids associated with hooked red algae and green algae halimeda fabiania rotaliids and textulariids as well as nummulitids are subordinated the samples were assigned to lutetian sbz13 16 according to the occurrence of nummulites cf lehneri alveolina ex gr elliptica idalina berthelini orbitolites complanatus slovenites decastroi and medocia blayensis at santa cesarea reticulate nummulites occur in association with alveolina spp and halkyardia minima marking the lower bartonian sbz17 three main facies associations have been recognised i larger porcellaneous foraminiferal grainstones with orbitolitids and alveolinids deposited into high energy shallow water settings influenced by wave processes that reworked the sediments associated with a seagrass ii grainstone to packstone with small porcellaneous foraminifera and abundant permanently attached gypsinids deposited in a more protected e g small embayment in situ vegetated environment iii bioclastic packstone with parautochthonous material reworked from the seagrass by rip currents and accumulated into rip channels in a slightly deeper environment the biotic assemblages suggest that the depositional environment is consistent with tropical to subtropical vegetated environments within oligotrophic conditions

nature of the early proterozoic outokumpu assemblage eastern finland abstract the 1970 ma old outokumpu assemblage consists of serpentinites gabbro and mafic metavolcanites with pelagic and chemogenic sediments lying in the early proterozoic 2200 1950 ma karelides of eastern finland its formation occurred after the development of the jatulian 2200 2000 ma quartzite dominated shelf sediments and prior to the deposition of the kalevian flysch the outokumpu assemblage has been compared to an ophiolite and though the lithologies are all present sheeted dykes excepted the internal stratigraphy suggests otherwise the mafic metavolcanites have a more depleted chemistry than n morb and were erupted into shallow water along with the deposition of pelagic shales carbonates and chemogenic sediments including metalliferous exhalites ultramafic sills intruded these rocks at a later stage prior to rapid subsidence and flysch deposition the recently discovered jormua ophiolite complex may constitute part of the depositional basement to the outokumpu assemblage and the kalevian flysch which formed over stretched crust in an ensialic basic

the molecular composition of cretaceous ambers identification and chemosystematic relevance of 1 6 dimethyl 5 alkyltetralins and related bisnorlabdane biomarkers abstract one of the major components of the organic solvent extractable fraction of cretaceous ambers is 1 6 dimethyl 5 isopentyltetralin a compound that has been incorrectly or not identified in previous reports on the molecular composition of cretaceous ambers here the purification and structural identification of 1 6 dimethyl 5 isopentyltetralin is reported from amber samples of the cretaceous penacerrada ii deposit at penacerrada alava basque cantabrian basin spain the structural identification of 1 6 dimethyl 5 isopentyltetralin allowed the complete identification of related compounds comprising the family of 1 6 dimethyl 5 alkyltetralins this suggests that those compounds with concentrations up to 27 of the total organic extract of amber from penacerrada are characteristic for labdane type biomarkers in cretaceous fossil resins and their distributions indicate different compositional families related to their botanical and topographic origin also the name amberene is proposed for the main molecule of this group the relative proportion of the amberene type compounds suggests three compositional families for the cretaceous spanish ambers

eoalpine and mesoalpine tectonics in the southern alps according to structural and stratigraphic data eoalpine and mesoalpine tectonics can be clearly recognized in the southern alps and distinguished from the better known neoalpine deformation

the nature and fate of natural resins in the geosphere iv middle and upper cretaceous amber from the taimyr peninsula siberia evidence for a new form of polylabdanoid of resinite and revision of the classification of class i resinites abstract analysis of three amber resinite samples collected from middle and upper cretaceous sediments in the taimyr peninsula siberia indicates that these materials are based on copolymers of biformene i and communol ii these resinites represent a previously undescribed form of class i polylabdanoid resinite definitions of the sub classes of class i resinites have been revised generalized to recognize the general relation between these samples and other class ib resinites and to facilitate classification of polylabdanoid resinites which do not necessarily incorporate communic or ozic acids

exceptional fossil record distribution of soft tissue preservation through the phanerozoic preservation of soft bodied fossil biotas konservat lagerstaten that preserve traces of volatile nonmineralized tissues readily degraded by bacteria are not evenly spaced through geologic time when compared to outcrop area exceptional faunas appear to be over represented in the cambrian and jurassic these concentrations in time correspond to particular environments indicating that controls on the distribution of exceptional faunas may have operated on a global scale the reduction in the number of exceptional faunas after the cambrian may reflect the evolution and diversification of deep bio turbators specific conditions favoring stagnation and episodic burial were required to ensure preservation in younger rocks

rb sr geochronology in the thompson belt manitoba implications for aphebian crustal development and metallogenesis the supracrustal metasediments of the thompson belt pipe and thompson groups show pronounced differences in rb sr age 1855 1685 and 1665 1575 ma respectively and initial sr ratio 0 7096 0 7166 and 0 7203 0 7233 however they have similar rb sr ratios 0 8 1 2 and the age and isotopic differences are attributed to differing degrees of postdepositional metamorphic reworking the sr growth trajectories of these metasediments define a broad band on the evolution diagram and indicate a probable maximum age of deposition of ca 2 0 0 1 ga furthermore the role of archean detritus in the depositional history of these sediments is quite limited based on isotopic data for the basement gneisses and adjoining granulites of the pikwitonei region comparison of these data with those for metagraywackes of the adjacent kisseynew gneisses average indicates that there were fundamental differences between the marine environments within which the two aphebian sedimentary sequences were deposited the hig

the significance of source versus process in the tectonic controls of magma genesis arculus r j 1987 the significance of source versus process in the tectonic controls of magma genesis in s d weaver and r w johnson editors tectonic controls on magma chemistry j volcanol geotherm res 32 1 12 despite the association of certain characteristic trace element signatures with particular tectonic environments of eruption there are accumulating data which would result in significant tectonic misassignments ambiguity of signals appears in active arc back arc systems of the southwestern pacific and particularly in some intracontinental plate suites given the selective preservation of continental as opposed to oceanic lithosphere inappropriate paleotectonic inferences are probable using trace element criteria alone strong relative fractionation of the alkalis and alkaline earth elements aee with respect to the rare earth elements ree in the majority of arc related magmas and a number of intraplate continental basalts is strongly suggestive of the involvement of hydrous fluids at some stages in the respective petrogenetic processes occurring in these two tectonic regimes in contrast fractionation of high field strength elements hfse such as nb and ta with respect to the ree in the same suites is most readily explained by the involvement at some stage in the magma formation process of high sio2 melts a number of widely applied tectonic discriminants makes use of aee hfse fractionation but the processes and sources involved in subduction zone petrogenesis may be duplicated during interaction of mantle derived basalt with the heterogeneous components of continental lithosphere both mantle and crust a significant role for both volatile dominated fluids and silicate melts is implicated in collision and some intracontinental plate magmatism

variations in abundances and distributions of isoprenoid chromans and long chain alkylbenzenes in sediments of the mulhouse basin a molecular sedimentary record of palaeosalinity abstract the abundances and distribution patterns of mono di and trimethylated 2 methyl 2 4 8 12 trimethyltridecyl chromans mttcs and long chain alkylbenzenes in extracts of marl 66 samples anhydrite 15 and halite 1 strata of the salt iv formation of the oligocene mulhouse basin are reported the distributions of the methylated mttcs indicate salinity changes of the upper part of a density stratified water column of the basin these variations are explained by a tectonically or climatically induced change in the supply of water of relative lower salinity to form a layer overlying the deeper water brine hence it is suggested that mesohaline 3 5 15 conditions in the surface waters were established as a result of periodic incursions of marine water and subsequent evaporation conversely during periods when the surface water was derived mainly from fresh water from the hinterland lower average salinity in the surface layer resulted the distributions of long chain alkylbenzenes also appear to record these changes

chemostratigraphy of the posidonia black shale sw germany i influence of sea level variation on organic facies evolution abstract during the toarcian widespread deposition of organic rich mudrocks black shales occurred across europe linked to a 3rd order sea level rise we provide a high resolution multi proxy chemostratigraphic study of the dotternhausen sections in sw germany embedded in a stratigraphic and palecological framework chemostratigraphy and paleoenvironmental reconstruction is based on rock eval and elemental analysis of bulk organic matter and biomarker analysis of aliphatic hydrocarbon fractions aliphatic biomarker ratios applied to reconstruct the facies development include pristane phytane and pristane phytane n c 17 n c 18 ratios carbon preference index c 27 c 29 sterane and hopane sterane distribution results show that sea level change exerted the major control on the composition of primary produced organic matter and on its redox controlled preservation changes in primary production and in the ratio of terrestrially versus marine derived organic matter take place drastically at the onset of black shale deposition the relative proportion of terrestrial versus marine biomass accumulation is independently assessed by highly correlative bulk organic matter properties hi values and biomarker ratios cpi the terrestrially derived end member yields hi values of 50 100 mg hc toc and cpi values of 1 4 2 0 whereas the marine end member has hi values of 600 700 mg hc toc and cpi values of 0 95 1 05 correspondingly the shift in plant versus bacteria derived biomass is discriminated by hi values and hopane sterane ratios data were grouped according to their position in the lowstand lst lower and upper transgressive tst highstand systems tract hst and maximum flooding surface mfz of the sequence stratigraphic framework occurrence of organic matter with a significant bacterial contribution is restricted to the lst and lowermost tst and shows hopane sterane ratios of 0 25 0 5 marine phytoplanktonic matter dominates the upper tst hst and mfz with organic matter giving hopane sterane ratios between 0 5 and 1 7 samples from the hst yield hi values between 450 and 500 mg hc toc which is consistently lower by 150 mg hc toc when compared to the tst the lower quality of the organic matter deposited in the hst is due to its longer settling times through a thicker oxygenated water column a strong correlation with relative sea level stand and the c 27 c 29 sterane ratio is observed lst exhibits c 27 c 29 sterane ratios of 0 7 during transgression values increase to 1 0 reaching a maximum at 1 4 during sea level highstand thus reflecting decreasing terrigenous input and shifts in near shore versus open marine algal communities episodic fluctuation of anoxia is discussed on the basis of a monsoonal climate model which infers significant surface run off during summer monsoon providing high nutrient supply and associated high primary productivity in combination with a density stratified water column excellent preservation conditions for organic matter were established dry winter conditions with inversion of the surface water flow regime led to seasonal export of bottom waters and episodic establishment of dysoxic conditions variations in the extent of annual flushing of sub basins on the toarcian shelf controlled long term organic matter accumulation rate paleoclimate variability and its connection with sea level stand is thus of paramount importance for different modes of organic matter accumulation and redox system stability

acoustic measurements of surface gravity wave spectra in monterey bay using mode travel time fluctuations earlier work by miller et al j acoust soc am 86 326 345 1989 suggested that the surface gravity wave frequency direction spectrum could be measured using acoustic tomography signals an experiment was performed in monterey bay california from 12 16 december 1988 to validate this earlier work during that period an acoustic tomography source with a center frequency of 224 hz and bandwidth of 16 hz was deployed continuously repeating its coded transmissions every 1 9375 s the transmissions were received on a number of modified sonobuoys placed on the continental shelf at a range of approximately 55 km although the acoustic propagation was complicated by the presence of the monterey submarine canyon a hybrid ray and mode interpretation explains the observations the main effect of the surface waves on the acoustic signals is determined to occur in the shallow continental shelf portion of the path on the shelf it is shown that the resolved acoustic normal modes exhibit the fluctuations in travel time described in our earlier work the acoustic measurements of the surface wave spectrum compared well with measurements made by a pitch roll wave buoy maintained in the area by the national data buoy center ndbc the acoustic and buoy spectra agreed well on the location of the peak swell frequency the root mean square rms wave amplitudes from the two measures agreed to within 7

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

amber and organic matter from the late oligocene deep water deposits of the central western carpathians orava podhale basin abstract the occurrence of amber in the central carpathian paleogene basin is reported here for the first time the amber has been analyzed by means of optical microscopic methods infrared spectroscopy gas chromatography mass spectrometry and pyrolysis gas chromatography mass spectrometry to understand the amber composition origin taphonomy alteration and diagenesis organic petrographic and reflectance analyses of organic matter from amber bearing sediment was carried out to get information about paleoenvironment and maturity of sedimentary rock analyses confirmed polylabdane structure associated with class ib type of amber and its possible origin from the conifer family araucariaceae it is characterized by a high degree of maturity where both temperature and exogenic processes have participated in its conversion heterogeneity of reflectance values in the resinite suggests that amber was not redeposited from an older and more mature sedimentary unit the discrepancy between the maturity of the amber and amber bearing sedimentary rock along with abundant char and inertinite macerals indicates a probability of thermal alteration of the amber under the influence of heat from a wildfire and increased maturity occurring before its ultimate burial in a deep sea environment the assemblage of terrigenous macerals and numerous char and inertinite particles which were found in amber bearing sediment as well as in the amber crust suggest forest swamp type vegetation affected by wildfires the presence of amber and predominantly terrigenous organic matter besides mud rip up clasts derived from freshwater sediments in deep marine deposits indicates a direct connection of terrestrial environments to the deep water depositional system

characterization of model evaporitic environments through the study of lipid components abstract a saline circuit has been studied as a model of coastal evaporite system the lipid composition of diverse salt ponds encompassing calcite gypsum and halite domains has been determined most of the lipid materials has been found in the carbonate samples and is related to algal cyanobacterial debris lipids in the gypsum domain are of heterotropic microbialorigin and extreme halophilic bacteria constitute the main lipid contribution in the halite samples n alkane distributions with high predominance of n docosane constitute a previously described feature of sedimentary evaporitic conditions that is charateristics of the intermediate calcite gypsum samples in the calcite domain the presence of c20 highly branched isoprenid olephines tetrahymanol and the large amounts of phytol constitute likely precursors of lipids usually found in evaporitic environments i e c20 highly branched isoprenoid alkanes gammacerane and high phytane pristane ratios their occurence point to dehydration and hydrogenations as two main diagenetic processes leading to the formation of evaporitic molecular markers

metavolcanic rocks of the la ronge domain in the churchill province saskatchewan geochemical evidence for a volcanic arc origin the la ronge domain in the churchill province of the canadian shield is a volcanic sedimentary plutonic belt of early proterozoic age geochemical data supported by geological evidence strongly suggest that the la ronge metavolcanics were emplaced in an island arc setting the metavolcanic rocks range from basalt through andesite to dacite and rhyolite calcalkaline and tholeiitic types are dominant with minor alkaline varieties classification based on the major elements produces ambiguous results because of mobility of these elements during metamorphism however relatively immobile minor and trace elements provide reliable characterization of the basalts in particular the latter display distinctive trace element properties and morb normalized geochemical patterns similar to those of recent volcanic arc basalts being enriched in incompatible elements of low ionic potential and depleted in those of high ionic potential the calcalkaline basalts are in addition enriched in th p ce and sm a minor within plate component is also displayed by some metabasalts suggesting that magma genesis in parts of the la ronge arc involved sub continental lithosphere rare earth element patterns show enrichment in the lree with little or no eu anomaly interpretation by means of trace element discrimination diagrams incorporating elements such as ti y nb zr cr th yb and ce provides clear evidence for emplacement in a volcanic arc tectonic setting

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

taphonomy of insects in carbonates and amber abstract the major taphonomic processes that control insect preservation in carbonate rocks limestones travertines and nodules are biological insect size and wingspan degree of decomposition presence of microbial mats predation and scavenging environmental water surface tension water temperature density and salinity current activity and diagenetic authigenic mineralisation flattening deformation carbonisation the major taphonomic processes that control the preservation of insects in fossil resins amber and copal are different but can be considered under the same headings biological presence of resin producers size and behaviour of insects environmental latitude climate seasonality resin viscosity effects of storms and fires soil composition and diagenetic resin composition insect dehydration pressure carbonisation thermal maturation reworking oxidation these taphonomic processes are geographically and temporally restricted and generate biases in the fossil record nevertheless where insects occur they may be abundant and very diverse taphonomic processes may impact on phylogenetic and palaeobiogeographic studies in determining the timing of the origin and extinction of insect groups and in identifying radiations and major extinctions taphonomic studies are an essential prerequisite to the reconstruction of fossil insect assemblages to interpreting the sedimentary and environmental conditions where insects lived and died and to the investigation of interactions between insects and other organisms

novel phenolic biomarker triterpenoids of fossil laticifers in eocene brown coal from geiseltal germany abstract novel phenolic triterpenoids were tentatively identified with known mono tri and tetraaromatic oleanane ursane and lupane hydrocarbons and natural product precursors amyrone amyrin in the extract of eocene fossil laticifers called affenhaar from the geiseltal lignites germany the novel phenolic terpenoids are mono and triaromatic hydroxytriterpenoids oh at position 1 2 or 3 of the oleanane ursane and lupane classes hydroxy 24 25 dinoroleana 1 3 5 10 12 tetraene hydroxy 24 25 dinorlupa 1 3 5 10 triene hydroxy 24 25 dinorlupa 1 3 5 10 19 22 tetraene hydroxy 24 25 26 27 tetranorursa 1 3 5 7 9 11 13 heptaene hydroxy 24 25 26 27 tetranoroleana 1 3 5 7 9 11 13 heptaene and hydroxy 24 25 26 27 tetranorlupa 1 3 5 7 9 11 13 heptaene the structures of the novel compounds were proposed based on the interpretation of the gas chromatography mass spectrometry data of the underivatized and silylated total extract

guidelines for evaluating petroleum source rock using programmed pyrolysis rock eval pyrolysis is used to rapidly evaluate the petroleum generative potential and thermal maturity of rocks accurate conclusions require programs every 30 60 ft 9 18 m understanding of interpretive pitfalls and supporting data such as visual kerogen vitrinite reflectance and elemental analyses the generative potential of coals is commonly overestimated by pyrolysis and is best determined by elemental analysis and organic petrography most coals show high s2 s3 5 and low hi values 300 mg hc g toc migrated oil and mud additives which alter rock eval data can sometimes be removed by special processing for immature rocks bimodal s2 peaks and pi values over 0 2 indicate contamination pyrolysis downgrades organic poor clay rich rocks which show lower hi and higher tmax values than isolated kerogen because of adsorption of pyrolyzate on the clays tmax values for small s2 peaks 0 2 mg hc g toc are unreliable tmax is affected by maturation organic matter type contamination and the mineral matrix s3 is sensitive to inorganic and adsorbed carbon dioxide and to instrumentation problems acidification of carbonate rich samples and proper maintenance improves s3 measurement constant sample weights 100 mg are recommended below a threshold weight tmax increases by up to 10 c and other parameters decrease organic rich samples which overload the detector can be diluted with carbonate detector linearity is determined by pyrolyzing various weights of an organic rich rock

biomarkers reveal the role of photic zone euxinia in exceptional fossil preservation an organic geochemical perspective photic zone euxinia pze has proven important for elucidating biogeochemical changes that occur during oceanic anoxic events including mass extinction and conditions associated with unique fossil preservation organic geochemical analyses of a 380 ma invertebrate fossil which included well preserved soft tissues from the gogo formation canning basin western australia showed biomarkers and stable isotopic values characteristic of pze and a consortium of sulfate reducing bacteria which lead to exceptional fossil and biomarker preservation the carbonate concretion contained phytoplankton green sulfur bacteria chlorobi and sulfate reducing bacteria biomarkers with an increasing concentration toward the nucleus where the fossil is preserved the spatial distribution of cholestane unequivocally associated with the fossilized tissue and its high relative abundance to the total steranes suggest that the fossil is a crustacean the presence of an active sulfur cycle in this devonian system including sulfate reduction and the resulting pze played a pivotal role in the preservation of soft tissue from the fossil and its associated low maturity biomarker ratios

terpenoids in extracts of lower cretaceous ambers from the basque cantabrian basin el soplao cantabria spain paleochemotaxonomic aspects the composition of terpenoids from well preserved cretaceous fossil resins and plant tissues from the amber bearing deposits of el soplao and reocin in cantabria northern spain have been analyzed using gas chromatography mass spectrometry and the results are discussed using the terpenoid composition of extant conifers as a reference amber is present at many horizons within two units of coastal to shallow marine siliciclastics of albian and cenomanian age the fossil resins are associated with black amber jet and abundant well preserved plant cuticle compressions especially those of the extinct conifer genus frenelopsis cheirolepidiaceae we report the molecular characterization of two types of amber with different botanical origins one of them is characterized by the significant presence of phenolic terpenoids ferruginol totarol and hinokiol and pimaric isopimaric acids as well as their diagenetic products the presence of phenolic diterpenoids together with the lack of abietic and dehydroabietic acids excludes both pinaceae and araucariaceae as sources for this type of amber the biological diterpenoid composition is similar to that observed for extant cupressaceae the second type of amber is characterized by the absence of phenolic terpenoids and other specific biomarkers some terpenoids with uncertain structure were detected as well as the azulene derivative guaiazulene our results suggest that the amber from cantabria could be fossilized resin from frenelopsis and other undetermined botanical sources the biological terpenoid assemblage confirms a chemosystematic relationship between frenelopsis and modern cupressaceae

application of the coherent to incoherent intensity ratio to estimation of ocean surface roughness from high frequency shallow water propagation measurements for acoustic propagation through a shallow ocean channel or waveguide the coherence between different transmissions is controlled primarily by the roughness of the ocean surface and to a lesser degree by fluctuations in the volume in this study the coherent to incoherent intensity ratio ctir is defined as a way to quantify the coherence between multipath transmissions and ocean surface rms wave height and wind speed a theory that connects the ctir and the coherent surface reflection coefficient is developed using both kirchhoff and small slope approximations as rough surface scattering models the ctirs have been evaluated over a period of several days using broad band experimental results from shallow water deployment of source and receiver arrays that span most of the water column estimates of wind speed and rms wave height obtained using these ctir calculations are compared with environmental measurements to demonstrate the validity of the theory

the la voulte lagerstatte callovian evidence for a deep water setting from sponge and crinoid communities the siliceous sponges and crinoids from the chenier ravine france lower callovian are used here as biological markers to characterize the palaeoenvironment of the adjacent and contemporaneous la voulte lagerstatte that is remarkable for its unique soft bodied fauna e g worms cirrate octopods vampire squids sponges are abundant with dominant hexactinellids 80 and lithistids 20 four lines of fossil evidence supported by recent analogues indicate that this sponge community inhabited deepwater setting under dysphotic or aphotic conditions 1 the dominance of hexactinellids 2 the prevalence of cone shaped and erect morphologies that usually characterize recent bathyal sponges 3 the close similarities with recent hexactinellids from the continental slope and 4 the lack of encrustation by photophilic organisms attachments of sponges on hard substrate e g crystalline basement and their preservation in soft sediments e g muds indicate heterogeneous bottom conditions the chenier fauna also contains small stalked asymmetric cyrtocrinid crinoids that are known to live on hard substrates in bathyal environments such as the sw pacific steep seamounts convergent palaeoenvironmental clues obtained from both crinoids and siliceous sponges support the notion that the la voulte area including the la voulte lagerstatte was situated in the upper part of the bathyal zone near the slope basin transition with a water depth most probably exceeding 200 m supporting evidence from heterogeneous substrates and complex fault systems indicate a depositional environment along the external part of the slope where steep topographies and blocks usually favour the settlement of cyrtocrinid crinoids and hexactinellid sponges la voulte may therefore be one of the rare and extremely precious mesozoic lagerstatten to have fossilized a deep marine environment

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

organic geochemistry and paleoenvironment of the early eocene pesciara di bolca konservat lagerstatte italy abstract exceptional preservation of fossils in so called konservat lagerstatten requires specific depositional regimes excluding disturbance of bottom sediments by either wave actions and currents or by benthic fauna we here describe a depositional model for the eocene pesciara di bolca konservat lagerstatte based on sedimentological paleoecological and detailed organic geochemical results sediments were deposited in a lagoonal like basin with stagnant bottom waters located on an extended carbonate platform that was sheltered from open marine waters by a submarine threshold run off from nearby land areas provided nutrients to support an algal community dominated by diatoms no fossil diatom shells have been identified but evidence for their presence is given by the high abundance of highly branched isoprenoids in extractable bitumens influx of terrigenous organic matter into the lagoon occurred in particular during deposition of the basal fish bearing level l1 here not only plant macrofossils amber spores and pollen but also the lipid composition indicated notable input of land plants via the presence of n c 24 to n c 32 carboxylic acids long chain n alkanes n c 27 n c 29 n c 31 and angiosperm wax triterpenoids the redox regime in general was strongly reducing as evidenced by the high concentration of sulfur vs organic carbon excellent kerogen preservation as shown by high hydrogen indices and low pristane phytane but high phytane n c 18 ratios the water column was highly stratified with anoxic saline bottom and fresh surface waters euxinic conditions with free reduced sulfur present in the photic zone could only be detected in sediments from the l1 horizon via traces of aromatic carotenoids derived from green sulfur bacteria chlorobiaceae which utilize h 2 s in anoxygenic photosynthesis the depositional regime is thus comparable to the lithographic limestones of solnhofen but based on biomarker evidence lacks the high salinities postulated for the latter biomarker composition indicates that best preservation conditions prevailed in the basal part of the studied section 0 7 m above datum but declined upon deposition of the upper part we interpret the body of the pesciara as a parasequence of the 4th order 0 01 0 5 ma with the lower part representing a relative sea level lowstand and the upper part a relative sea level highstand

effects of thermal maturity on biomarker distributions in gondwana coals from the satpura and damodar valley basins india abstract organic geochemistry of gondwana coals especially the distribution of molecular fossils or biomarkers is not well constrained throughout the world in this study we have therefore evaluated biomarker signatures along with bulk organic matter and petrographic characteristics in coal samples collected from two gondwana basins in india satpura basin kanhan coalfield and damodar valley basin jharia coalfield from both coalfields the samples were collected from the lower permian barakar formation which is one of the major coal bearing strata in india a significant variation in thermal maturity levels in the samples is indicated by rock eval pyrolysis and petrographic analysis with the kanhan samples generally belonging to immature to early mature stage while the jharia samples display characteristics of overmature coals this variation in the thermal maturity strongly affects the biomarker distributions especially the terpenoids hopanes and steranes were considerably degraded due to thermal maturation and were below detection limit in the overmature samples presence of aliphatic diterpanes ent 16 h kaurane 16 h phyllocladane as well as aromatic diterpanes retene methylretenes tetrahydroretene simonellite and bisnorsimonellite in low maturity samples indicate terrestrial input possibly from the primitive conifers however the aliphatic and aromatic diterpanes were below detection limit in overmature samples making it difficult to infer their source distributions of polycyclic aromatic hydrocarbons pahs are also controlled by thermal maturity levels as evident from difference in pah ratios in the low and high maturity samples

salinity stratification in the permian phosphoria sea a proposed paleoceanographic model the late permian phosphoria formation of the western united states contains 1 7 10 12 t of phosphate and locally as much as 32 9 total organic carbon the mineral wealth of the phosphoria formation is generally attributed to late permian upwelling along the western margin of the continent unlike in most modern environments upwelling in the late permian occurred proximal to a broad shallow evaporative sea rather than an abrupt continental margin evaporite deposits that are contemporaneous with the organic and phosphate rich strata are present within the phosphoria and adjacent basins elevated concentrations of the biomarker gammacerane are ubiquitous in the organic rich facies of the phosphoria formation which suggests that the basin was salinity stratified depositional environments incorporating both upwelling and salinity stratification are unusual and poorly documented in modern settings we infer the presence of salinity stratification in the phosphoria basin and propose a paleoceanographic model of the phosphoria sea during the deposition of organic and phosphate rich sediment from the western margin of the continent upwelling water flowed into the evaporative phosphoria sea replacing and overriding hypersaline bottom water that drained westward this paleoceanographic model of the phosphoria sea may help to explain the distribution and preservation of organic and phosphate rich strata in the phosphoria formation

the messinian diatomite deposition in the mediterranean region and its relationships to the global silica cycle abstract diatomites constitute a widely represented lithology in the messinian sections of the circum mediterranean neogene marginal basins although traditionally interpreted as genuine evidence of the gradually restricted conditions that characterized the mediterranean just before the messinian salinity crisis their coeval occurrence with a global intensification of the opaline production in the world oceans late miocene early pliocene biogenic bloom suggests that an integrative analysis of the origins of these sediments is necessary a comprehensive analysis of the geological and paleontological records suggests that the synergistic intervention of abiotic tectonic and climate reconfigurations and biotic expansion of grass dominated opal rich biomes controlling factors may have promoted a remarkable enhancement of silica flux from continents to oceans which in turn can explain the opaline burst that occurred during the late miocene at both the global and mediterranean scale the finely laminated pattern and the rich fossil content of diatomaceous deposits that are usually considered to be byproducts of anoxic conditions are briefly discussed some studies seem to indicate that instead of anoxia the aggregation and sedimentation of diatom tests may play a critical role in these processes the lower messinian diatomites of the mediterranean region are generally interbedded with organic rich sediments sapropels clearly attesting prolonged precessionally controlled periods of basin stratification and bottom water anoxia or hypoxia a causal relationship between sapropel and diatomite deposition in the mediterranean is proposed considering the possible interplay between stratification adapted diatoms and anaerobic bacteria and their respective role in influencing the marine silica cycle

identification of aryl isoprenoids in source rocks and crude oils biological markers for the green sulphur bacteria abstract a series of c13 to c31 aryl isoprenoids 1 alkyl 2 3 6 trimethylbenzenes have been identified in reef hosted oils and their source rocks from the middle and upper silurian of the michigan basin and middle devonian of the alberta basin canada their structure has been confirmed by unambiguous synthesis of the c14 member of the series their structure and isotopic composition indicate that they are derived from isorenieratene from the chlorobiaceae family of sulphur bacteria these results are consistent with geological and geochemical studies that show that the source rocks were deposited under metahaline to hypersaline sulphate and sulphide rich water columns the distribution of other biomarkers in these oils and source rocks indicates that a diverse biota contributed organic matter to the source environment in conjunction with the aryl isoprenoids they show that there is a remarkable similarity in composition between the two sets of oils and source rocks despite their great temporal and geographic separation this reflects the similarity of their environments and emphasizes the importance of sedimentary facies in controlling the composition of organic matter in source rocks and their derived oils

aromatic hydrocarbon biomarkers in terrestrial organic matter of devonian to permian age abstract this paper presents the results of a detailed study on the occurrence and distribution of alkylnaphthalenes and alkylphenanthrenes in 39 coal and sediment samples from the late palaeozoic containing predominantly terrestrial organic matter most of the samples represent the euramerian flora realm and originate from locations beyond the variscan front in eastern northern and central europe i e especially england and the moscow basin the samples are of relatively low maturity 0 32 to 1 80 rr and consist mainly of mixtures of type iii and ii kerogen quantification of the c0 to c4 naphthalenes and the c0 to c4 phenanthrenes showed that these compound classes were highly abundant in all samples aromatic hydrocarbon maturity parameters in general are in good agreement with measured vitrinite reflectance values 1 2 7 trimethylnaphthalene an assumed diagenetic product of oleanane type biomarkers was present in all investigated samples this observation provides evidence that oleanane type lipids were biosynthesised by organisms predating the evolution of angiosperms or that assumed formation pathways for 1 2 7 trimethylnaphthalene are insecure 1 2 8 trimethylphenanthrene was significantly enriched in samples from the permian and the one sample from the devonian investigated in this study the precursor s of 1 2 8 trimethylphenanthrene therefore may have been produced by organisms which were least abundant in the carboniferous depositional environments represented by our samples

a new fossil lagerstatte from the lower eocene of lessini mountains northern italy a multidisciplinary approach hemipelagic dark limestones within calciturbiditic deposits at monte solane in the western lessini mountains of northern italy yield a fish fauna dominated by stomiiforms a minor component of the fossil assemblage is represented by a macroalgal non calcareous flora associated with rarer terrestrial components including few angiosperm leaves and seeds micropaleontological foraminifera dinoflagellate cysts sedimentological and geochemical proxies tex86 indicate a deposition of the fossil bearing bed in a hypoxic to possibly anoxic warm restricted basin high precision dating based on rich foraminiferal and calcareous nannoplankton content allows ascribing the site to the upper part of the ypresian lower eocene the site is slightly older than the ypresian worldwide famous shallow water bolca konservat lagerstatte located in the same region convergent paleoenvironmental clues based on both microfossils and ichthyofauna indicate that the sediments were deposited in the upper bathyal zone probably between 300 and 600 m solane is therefore one of the rare and precious eocene lagerstatte to have fossilized in a deep marine setting the site contains the oldest cenozoic record of an ichthyofauna dominated by meso bathypelagic taxa

polar aromatic biomarkers in the miocene maritza east lignite bulgaria aromatic and polar compounds of lignite lithotype bitumens maritza east were analyzed diterpenoid phenols and ketophenols i e mainly ferruginol sugiol hinokione and products of their diagenetic transformations were identified as the dominant biomarkers a variety of sesquiterpenoids was present as well these compounds provided evidence for the assumption that members of the cupressaceae s 1 are the coal precursors polar triterpenoids i e lupeol lupenone adiantone and hopanones were present in subordinate quantities in the humoclarain sample these biomarkers support an input of deciduous angiosperm vegetation to the peat swamp source matter three diagenetic transformation schemes for the diterpenoid phenols ketophenols are proposed 1 ferruginol and or sugiol alteration through dehydrogenation demethylation and ring b cleavage 2 hinokione aromatization to simonellite and 3 7 ketototarol change through 7 ketototar 5 enol to 20 nor 3 oxo totara 5 10 6 dienol the identified diterpenoids demonstrated the presence of gymnospermae in the coal forming community furthermore the phenolic diterpenoids indicated a specific input of organic matter from conifers of the cupressaceae taxodiaceae or podocarpaceae as the most abundant trees in the coal forming swamp

early eocene amber from the pesciara di bolca lessini mountains northern italy abstract the occurrence of amber from the world famous fossil lagerstatte of pesciara di bolca verona province is here reported for the first time this amber has been carefully analysed by means of infrared spectrophotometry ftir thermogravimetric analysis tg differential thermogravimetric analysis dtg and elemental chemical analysis then the amber from bolca has been compared with other ambers of similar age among them a sample from the cava rossi quarry monte di malo vicenza province shows striking similarities in all the physical chemical characters the fossil content of the amber levels of the pesciara and cava rossi was examined with respect to the palynomorphs and larger foraminiferans this permitted to ascertain that the two amber levels are substantially isochronous within the resolution power of the larger foraminiferan biozones according to the shallow benthic biozonation the age is in both cases sbz 11 or middle cuisian early eocene moreover the fossil assemblages allowed to reconstruct the palaeoenvironments stressing they were in both case on a shallow carbonate platform relatively close to the shoreline the pesciara palaeoenvironment was very close to the continental areas and with peculiar conditions allowing the exceptional preservation of the fishes instead the cava rossi palaeoenvironment was more distal and open to marine influxes

results from the 1984 marginal ice zone experiment preliminary tomography transmissions implications for marginal ice zone arctic and surface wave tomography during the 1984 marginal ice zone experiment mizex 84 a 224 hz center frequency acoustic tomography sound source was deployed off spitsbergen norway in 1200 m of water over the course of 10 days it transmitted hourly signals that were recorded by receivers at two locations one moving with the ice pack and the other stationary the main purpose of the transmissions was to answer the following questions which are important to the feasibility of acoustic tomography in marginal ice zone miz and arctic regions 1 can the signals be coherently averaged to improve the signal to noise ratio of the multipath arrival peaks 2 are the surface scattering and bottom reflection losses acceptably low 3 are the arrivals identifiable 4 are the arrivals stable and 5 are the arrivals resolvable our data analysis provides generally positive answers indicating that ocean acoustic tomography is feasible in miz regions however the shallow bathymetry in the mizex 84 area increases the difficulty of the problem consistent with the observations of palmer et al 1985 and deferrari and nguyen 1985 in the shallow water of the straits of florida in analyzing the data it was noticed that the phase or travel time fluctuation spectra of surface interacting rays exhibited a shape similar to that of the surface wave frequency spectrum this suggested that tomography could also measure the surface wave field a previously unexplored possibility theoretical expressions are derived in this paper which relate the acoustic fluctuations to standard surface wave descriptors e g the frequency directional spectrum these expressions are then used to compute the surface wave frequency spectra for 2 days of data though these spectra are uncorroborated by other wave spectrum measurements e g wave rider buoys the rms wave heights predicted by the acoustics agree well with rms wave heights estimated by wind force data

conifer and angiosperm biomarkers in clay sediments and fossil plants from the miocene clarkia formation idaho usa the aliphatic lipids and terpenoids of conifer and angiosperm macrofossils and the clay sediment from a new site p 37 of the miocene clarkia formation idaho usa were analyzed to evaluate the preservation of characteristic conifer and angiosperm biomarkers in the sediment series of aliphatic lipids terpenoids and steroids similar to the biomarkers found in type locality clarkia p 33 were the predominant compounds in the sediment and in the fossils long chain aliphatic lipids were major compounds in the fossil plants and the sediment but a differentiation of angiosperm and conifer sources is not possible due to their common distribution among all vascular plants in addition to previously reported terpenoids diterpenoids of a conifer origin and several angiosperm derived polar triterpenoids of the oleanane lupane ursane and friedelane classes are reported here for the first time from the clarkia sediments the conifer shoots taxodium glyptostrobus calocedrus contained characteristic conifer biomarkers such as abietane type diterpenoids while characteristic angiosperm triterpenoids were predominant in the angiosperm leaves betula quercus lithocarpus the biomarker compositions of the taxodium and glyptostrobus shoots match the terpenoid patterns previously reported from fossil seed cones of the same genera although conifer macrofossils contribute about 45 to the flora of site p 37 characteristic conifer biomarkers occurred in the sediment in only low amounts while the angiosperm derived triterpenoids were present in comparatively higher abundances the results indicate that the conifers are under represented compared to the angiosperms according to the terpenoid composition of the sediment extract this may be due to the presence of small angiosperm derived particles leaf detritus wax in the sediment and or migration of leaf waxes from the angiosperm leaves into the sediment in contrast the diterpenoids are trapped in the resinous woody tissue of the conifers and are thus disseminated less into the sediment

ftir and statistical studies on amber artefacts from three romanian archaeological sites abstract in the present study fourier transform infrared spectroscopy in the reflectance mode ftir reflectance was performed on well preserved archaeological amber originating from three romanian archaeological sites of roman and byzantine cultures which did not allow sampling material resulting spectra were subjected to multivariate data analysis mda using principal components analysis pca in the light of the ftir reflectance bands of archaeological samples from the region 1275 to 1155 cm 1 and 900 600 cm 1 we could conclude that the samples from first two locations rosia montan and nuf ru are made from amber of baltic origin in the case of the third location isaccea we take into account the possibility of a mixture of raw materials both baltic and romanian amber these assertions are supported by statistical analysis and the historical context besides the ftir spectra comparison or other analytical data it is very important to correlate any information about the material colour conservation status historical context connections with other artefacts and the statistical analysis in order to favour safe conclusions

light rare earth enrichment of supra subduction zone mantle evidence from the troodos ophiolite cyprus geochemical data including rare earth elements ree are presented for the primitive high mgo glassy lavas from the upper sections of the troodos ophiolite al2o3 tio2 ratios are used as an index of degrees of mantle melting and or successive depletion events the sources of the lavas have undergone both a ubiquitous introduction of low field strength elements and a selective addition of light ree suggesting a two stage mantle contamination model correlations between al2o3 tio2 ratios depletion index and the amount of light ree enrichment present in the lavas suggest a component induced melting model in this model progressive addition of a light ree component induced higher degree batch melts or enabled melting of highly refractory source material the light ree enrichment event is shown to be of the same character across the ophiolite but it is limited to the older ocean crust and a transform influenced regime

the bolca lagerstatten shallow marine life in the eocene the eocene limestones around the italian village of bolca occur in a series of distinct localities providing a unique snapshot of marine life in the early cenozoic famous for its fishes the localities of bolca also yield diverse invertebrate faunas and a rich but relatively understudied flora most fossils from bolca derive from the pesciara and monte postale sites which bear similar fossils but are characterized by slightly different taphonomic and environmental profiles although not precisely contemporaneous the age of these principal localities is well constrained to a narrow interval within the ypresian stage c 50 49 ma this places bolca at a critical time in the evolutionary assembly of modern marine fish diversity and of reef communities more generally

existence of a marginal basin within the circum superior belt geochemical evidence from the churchill superior boundary in manitoba canada mafic volcanic rocks incorporated within the churchill superior boundary zone at ospwagan lake moak lake assean lake and the fox river belt constitute part of the circum superior belt major and trace element data have been obtained from mafic and ultramafic volcanic rocks from four localities the data provide a means of comparing and contrasting the geochemistry of the rocks from the portion of the circum superior belt surrounding the archean superior province in manitoba with other units from elsewhere in the belt and with rocks from the adjacent proterozoic churchill province major element geochemical data are consistent with the rocks having originally formed in a oceanic environment trace element and rare earth element data suggest that the environment was a marginal basin al2o3 tio2 ratios indicate that the magmas were derived from a mantle source by small degrees of partial melting high field strength element patterns show that the mantle source region giving rise to the rocks was relatively uniform in composition trace element mid ocean ridge basalt morb and chondrite normalized patterns indicate similarities in alkali element enrichment for the rocks at asean and ospwagan lakes virtually all the rocks have ti zr nb y and p levels morb which is consistent with the mantle source region having undergone a small degree of partial melting zr p ratios for the rocks from the fox river belt are consistently lower than those from the other localities and the assean lake rocks show slight enrichment in light rare earth elements which may suggest local compositional variability in the mantle source regions supplying the magmas to the fox river belt and the ospwagan assean and moak lake areas

controlled excavations in the pesciara and monte postale sites provide new insights about the palaeoecology and taphonomy of the fish assemblages of the eocene bolca konservat lagerstatte italy abstract the eocene konservat lagerstatte of bolca italy is famous for the abundance and exquisite preservation of its fossils although the bolca sites have provided one of the most studied ichthyofaunistic fossil assemblages of the world several aspects about the community structure and the biostratinomic processes that led to the accumulation of its fish remains have been neglected or underestimated in order to improve our knowledge concerning the palaeoecology and palaeoenvironment of bolca a quantitative palaeoecological and taphonomic analysis of the fish remains collected during controlled excavations at the pesciara and monte postale sites is presented herein the results of these analyses concur to suggest that these two sites have different speciose fish assemblages and different depositional contexts the high quality preservation of the fishes from the pesciara site has allowed for the species level identification of most of its specimens providing a good resolution of its palaeoecological spectrum the pesciara fish assemblage is defined by a sharp oligarchic structure clearly dominated by planktivorous taxa the taphonomic features confirm that the sediments were deposited in an intraplatform basin in which anoxic conditions at the bottom and the development of the biofilm acted as promoters of high quality fossil preservation on the other hand the moderate preservation quality of the fishes from monte postale does not allow for most of the specimens to be identified at the genus or species level making it difficult to interpret the ecological and trophic relationships within this assemblage nevertheless the abundance of marine and terrestrial plants coupled with the large number of invertebrates including abundant corals concur to suggest that the sediments of monte postale were likely deposited close to an emerged coastal area characterized by mangroves seagrass and coral reefs the prominent disgregation of fish skeletons coupled with the unimodal dispersion of the elements and bioturbations clearly indicate a high degree of disturbance in the monte postale palaeoenvironment suggesting at least periodic aerobic conditions at the bottom

facies analysis palaeoenvironmental reconstruction and biostratigraphy of the pesciara di bolca verona northern italy an early eocene fossil lagerstatte abstract the world famous pesciara di bolca fossil lagerstatte has been examined in its palaeontological and sedimentological aspects a re examination of the co occurring age diagnostic larger foraminifers alveolina and nummulites indicates a sbz 11 late ypresian age sedimentological characters allowed us to distinguish between autochthonous micritic limestones and allochthonous biocalcarenites biocalcirudites the latter are the product of penecontemporaneous transport from nearby areas the depositional model here proposed involves a basin with restricted circulation and a prevailing micrite sedimentation this basin was affected by relative sea level oscillations and coarser grained storm induced deposition the palaeoenvironmental reconstruction suggests neighbouring emerged land and very shallow sea bottoms inhabited by large foraminifers such as alveolina and nummulites as yet it is unclear whether a true coral reef was present nearby the bottom on which the pesciara deposits accumulated is interpreted as poorly oxygenated possibly with stromatolite like bacterial mats thus allowing the exceptional preservation of the fish and plants

chlorobiaceae in palaeozoic seas revealed by biological markers isotopes and geology biomarker hydrocarbons in oils and sediments have considerable potential for assessing the nature of biological processes in the past but only a few can be uniquely related to particular organisms reef hosted oils in the silurian of the michigan basin canada and the devonian of western canada have high abundances of 1 alkyl 2 3 6 trimethylbenzenes their precise structures suggest that they are diagenetic products of aromatic carotenoids of the green sulphur bacteria individual components are enriched in 13c by 7 8 relative to the saturated hydrocarbons of the same oil an isotopic anomaly of this magnitude and direction correlates with a component of photosynthetic carbon assimilation by the reductive tricarboxylic acid cycle these results together with data on palaeoenvironments provide compelling evidence for the existence in ancient restricted seas of microbial communities containing chlorobiaceae organisms with distinctive biochemistry which leave morphologically identifiable remains

petrogenesis of ultramafic and mafic rocks of the thompson nickel belt manitoba abundant sill like bodies of serpentinized ultramafic rocks with associated nickel sulfide deposits are found on the western side of the thompson nickel belt near the moak lake setting lake cataclastic fault zone the ultramafic rocks range in composition from dunite to orthopyroxenite and feature variable alteration chemical variation across the bodies is suggestive of in situ differentiation controlled mainly by olivine and orthopyroxene relative abundances of some elements incompatible for olivine and orthopyroxene suggest a parental liquid of komatiitic affinity ultramafic and mafic rocks are petrogenetically linked a high degree of partial melting of mantle material and subsequent low pressure crystal fractionation are responsible for the spectrum of composition from ultramafic to mafic

the importance of atmospheric input of terrestrial organic material to deep sea sediments the concentrations of lipids were determined in atmospheric particle gas and rain samples collected from the tropical north pacific to assess lipid sources transport mechanisms and fluxes to the ocean surface four lipid compound classes aliphatic hydrocarbons fatty alcohols fatty acid esters and salts all unequivocally show a terrestrial vascular plant source these aerosol lipids originate from wind erosion of asian and american soils and direct emission from vegetation the major fluxes result from rain rather than dry deposition these fluxes are large enough to have a major potential impact on the inventory of terrestrially derived lipid material found in deep sea sediments this has been showm for n alkanes fatty alcohols fatty acids total lipids and for organic carbon by comparing atmospheric and sediment trap fluxes with sediment accumulation rates it is suggested that some biogenic terrestrial material is more protected from degradation than marine derived material

molecular indicators of palaeoenvironmental conditions in an immature permian shale kupferschiefer lower rhine basin north west germany from free and s bound lipids a study of the distributions of free and s bound biomarkers and their 13c values in the extract of a bulk sample of the permian kupferschiefer from the lower rhine basin has been carried out to provide a more detailed characterization of the biological inputs the distributions and isotopic compositions of selected components released from nickel boride desulphurization have been compared with those of components in the free fraction the free biomarkers occur in greater abundance than their s bound counterparts the distribution and carbon isotopic composition of both free and bound components in the extract indicate a major cyanobacterial and algal input likewise the free and bound aromatic hydrocarbons contain components which reveal an origin from the carotenoids of chlorobiaceae green sulphur bacteria providing molecular evidence for the occurrence of photic zone anoxia in the water column most of the components in the complex mixture of mono di tri and tetra aromatics in the free aromatic hydrocarbon fraction result from cyclization and aromatization reactions

tertiary extension in the southern trento platform southern alps italy the southern trento platform southern alps ne italy was the locus of abundant mafic volcanism associated with paleogene extensional tectonics during the pal eocene and throughout the eocene a nnw sse trending graben the alpone agno graben aag developed in the eastern lessini mountains the graben was filled with basaltic volcaniclastics calcarenites and lava flows the aag is a half graben system probably bounded by rotational listric normal faults most faults in the graben dip towards the wsw paleostress analysis within the aag shows that during the eocene the direction of horizontal extension was ene wsw the volcanic activity continued into the oligocene however the relation between oligocene tectonics and volcanism remains unclear gravimetric and magnetic anomalies in conjunction with the crustal thickness variations suggest a locus of lithospheric thinning slightly off axis from the aag this can be explained by an overall asymmetric extensional geometry dominated by a wsw dipping detachment fault the paleogene geodynamic scenario of the trento platform suggests that the aag developed as a foreland extensional response to the active collisional convergence between the european and adriatic plates neogene compressional tectonics reactivated some of the paleogene normal faults as strike sup faults

ecology of extant nummulitids and other larger benthic foraminifera applications in palaeoenvironmental analysis abstract larger benthic foraminifera lbf are important contributors to modern and ancient tropical shallow marine sediments over the past 30 years a substantial body of literature has built up on the ecology of modern lbf especially in terms of their environmentally sensitive depth distribution reproductive strategy and morphology and the symbiotic relationship between many larger foraminifera and photosynthetic algae over the same period the extinct genus nummulites which is abundant in eocene sediments of southern europe north africa and the arabian peninsula has increasingly been studied principally because significant volumes of hydrocarbons have been discovered reservoired within nummulitic limestones offshore tunisia and libya the modern ecological studies of lbf provide a powerful tool with which to develop palaeoecological models for fossil nummulites and other symbiont bearing larger foraminifera in the rock record

cementation and blackening of holocene sands by peat derived humates a case study from the great dune of pilat landes des gascogne southwestern france abstract the base sand layers of the aeolian great dune of pilat which stretches along the coast of arcachon bay have been locally impregnated with a dark brown to black amorphous organic substance of humate composition the humate cemented sand forms a well indurated horizon 40 50 cm in thickness that developed immediately beneath the holocene peaty layer p1 paleosoil the humate identified by means of ft ir and raman micro spectroscopy acted both as a cementing agent and as a coloring agent it formed thin coats and meniscus cements between individual sandstone grains which in turn caused the dark asphaltic like appearance of the sandstone field observations combined with geochemical analyses and the presence of identical geochemical compounds recognized in the peat and sandstone humate cement suggest that the peat containing low coalified rr 0 2 fragments of higher submerged and floating plants and marine algae deposited in a saline and reducing environment served as an obvious source rock for the humate the humate derived from decaying organic remains that descended from the peat into the permeable sand where it indurated irreversibly over a period shorter than 3500 years the present day actions of waves and tides contribute to the erosion of the frontal parts of the humate impregnated sandstone horizon resulting in the formation of the dark rounded sandstone slabs and pebbles that are deposited on nearby beaches this process provides a fine example of recent black pebble formation that derived from pre existing organic matter impregnated source rocks in contrast to their tropical carbonate counterparts however the humate induced blackening of the sandstone pebbles appears to be relatively unstable as the impregnated fragments bleach when exposed to air and seawater for a few seasons

aromatic hydrocarbon composition of the permian kupferschiefer in the lower rhine basin nw germany the aromatic hydrocarbon composition of 25 samples of permian kupferschiefer from the lower rhine basin of nw germany has been investigated using gc gc ms and direct probe ms analysis two narrow sampled profiles were investigated with respect to compositional changes during kupferschiefer sedimentation and samples from 13 different wells covering a depth range from 350 to 1000 m were included in order to study temperature sensitive variations in the kupferschiefer trimethyl substituted aryl isoprenoids in the range from c11 to c21 occur these compounds presumably are degradation products of isorenieratane which is also present in the extracts within the profile the amount of a preferentially occuring c29 chroman increases from the bottom to the top of the kupferscheifer by a factor of about 2 5 the chroman distribution observed in the kupferschiefer points towards euhaline to mesohaline seawater during sedimentation moreover in the investigated profiles a terrestrial source input mainly in the bottom most part of the shale is reflected by the occurrence of a monoaromatic c24 chrysene derivative presumably derived from ring a degradation of pentacyclic triterpenes

organic matter composition and distribution through the aptian albian lacustrine sequences of the araripe basin northeastern brazil abstract the main characteristics and distribution of organic matter have been studied through several aptian albian lacustrine units rio da batateira crato and ipubi formations araripe basin ne brazil six main facies have been distinguished on the basis of their lithological sedimentological characteristics and the type and amount of organic matter 1 marginal lacustrine deltaic massive to coarsely laminated mudstones and sandstones found as lenticular sheet and channel infills 2 oxic marginal lacustrine massive to poorly laminated mudstones 3 oxic suboxic inner lacustrine mudstones and laminated bioclastic mudstones 4 anoxic inner lacustrine dark mudstones 5 anoxic inner lacustrine dark clay carbonate rhythmites and 6 anoxic inner lacustrine finely laminated dark micritic limestones these facies make up decimeter to several meter thick parasequences which stack up in several tens of meters thick successions water level changes and variations of the detritic sediment contribution in the basin controlled the evolution of the depositional system palynomorph associations showed that the lacustrine system evolved in an arid semiarid tropical area where the most characteristic flora consisted of conifers gnetales bennettitales and early angiosperms in facies 1 to 3 organic matter was scarce poorly preserved and mainly derived from higher land plants facies 4 is characterised by containing abundant algal bacterial derived well preserved organic matter facies 5 and 6 contained mainly branchlets and pollen debris blown by the wind or fed by lacustrine underflows the pattern of organic matter accumulation and preservation corresponds well with cyclical palaeoenvironmental changes from anoxic to oxic bottom conditions and from a fresh to saline upper water layer which affected the shallow lacustrine system the deposition of thin organic matter rich mudstones facies 4 probably occurred during higher water levels which resulted in relatively low salinity waters and low detrital contribution to the inner lacustrine zones less significant organic matter accumulation is recorded in the clay carbonate rhythmites and in the limestones facies 5 and 6 due to scarce autochthonous aquatic organic matter deposition and pervasive intense bacterial degradation caused by persistent meromictic conditions large differences in the degree and path of evolution of the humic material derived from higher land plants have been detected depending on the depositional conditions the humic material in the oxic facies underwent humification and gelification and had the highest huminite reflectances whereas it showed suppressed reflectance values in the oil shales facies 4 and in the carbonate dominated facies in the latter extensive bacterial reworking of humic material is also observed these differences are considered significant and applicable to other case studies in terms of evaluating the maturity of organic matter in ancient lacustrine systems

geochemical characterization of malm zeta laminated carbonates from the franconian alb sw germany ii abstract during jurassic times especially within the malm stage local depressions formed on the eastern bavarian carbonate platform that were surrounded by wall reefs this created a unique depositional environment where in an open marine setting stagnant and anoxic bottom waters developed in an intra reef depression anoxic conditions were stabilized below wave base by enhanced salinity in the bottom waters and establishment of a density stratification biomarker analysis was applied to characterize palaeosalinity and redox conditions utilizing organic sulfur compound methylated chroman hopanoid and saturated isoprenoid distributions prevention of terrigenous influx by protecting reef walls lead to iron deficiency in intra reefal sediments causing early diagenetic sulfurization of functionalized lipids absence of clay mineral catalysts and early sulfurization favored an unusual steroid distribution lacking rearranged analogues but providing coexistence of saturated steranes with and configuration 13 17 spirosterenes unknown sterenes and steradienes as well as mono di and triaromatic steroids desulfurization of the polar fraction was carried out for two samples to verify that palaeoenvironment reconstruction based on free hydrocarbon and heterocompound distribution was not invalidated by sulfur quenching of selected compounds gammacerane was found to be the only component to occur exclusively in the sulfur bound fraction only minor amounts of hydrocarbons were released upon desulfurization implying that free bitumen analysis was applicable for organofacies characterization organic petrological investigation of organic mats revealed the presence of two different types of such structures comparison of organoclast fluorescence spectra with those of extracted porphyrin fractions indicate an origin of porphyrins exclusively from cyanobacterial mats whereas algal dominated mats yield no porphyrins this aims towards a better localization of specific biomarker origin in geological samples

oceanographic conditions as a trigger for the formation of an early miocene aquitanian konservat lagerstatte in the central paratethys sea article i nfo article history an exceptional early aquitanian konservat lagerstatte with well preserved vertebrate and invertebrate fossil assemblages has been studied in the north alpine foreland basin of upper austria the finely laminated sediments were deposited along the northern shelf of the central paratethys sea micropaleontological foraminifers dinoflagellates and geochemical organic carbon sulphur carbonate content biomarker stable isotopes proxies indicate intense upwelling in addition episodically increased coastal runoff provided large amounts of nutrients stimulating primary productivity all evidence suggests deposition within dysoxic anoxic bottom waters of an oxygen minimum zone along the outer shelf and upper slope fossil assemblages show specific planktic and nektic associations in distinct intervals of the section various mechanisms are discussed to explain their origin 1 blooms of pteropods and calcareous nannoplankton reflect short term peaks in primary productivity increased coastal runoff and or intensified upwelling activity are considered as trigger mechanisms for providing the nutrients 2 allochthonous associations of the cephalopod aturia with brown algae suggest a two fold transport mechanism shells of the offshore living cephalopods were transported post mortem to the coast by surface currents and or wind currents episodic flooding events and storms mixed the accumulated shells with the algae and moved them offshore the latter process also seems to apply to several pipefish accumulations observed in the section 3 multi species vertebrate accumulations of fish and dolphins are considered parautochthonous as their habitat is in good agreement with the reconstructed paleoenvironment 4 benthic macrofauna is scarce and of low diversity it mainly consists of bivalves adapted to dysoxic environments and is thus interpreted to be autochthonous

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

interpreting rock eval pyrolysis data using graphs of pyrolizable hydrocarbons vs total organic carbon kerogen the major organic component of sedimentary rocks is commonly analyzed by rock eval pyrolysis plotting the data on a graph of s 2 vs total organic carbon toc and determining the regression equation is the best method for determining the true average hydrogen index and measuring the adsorption of hydrocarbon by the rock matrix such a plot also indicates the type of kerogen present and avoids the problem of increasing hydrogen index with total organic carbon content with the s 2 vs toc diagram the organic component of different suites of samples may be compared and their petroleum generation potentials established as an example the diagrams are used to evaluate the sedimentary environments and petroleum potential of the paleogene evaporitic sediments of the mulhouse basin alsace france

short paper a standardized model for tethyan tertiary carbonate ramps low latitude carbonates in massive and clinoform bedded sheets termed ramps occur throughout the tertiary tethyan realm and are characterized by recurring biofacies usually including large foraminifera rhodolithic algae coralgal patch reef and gastropod dominated sequences all can be interpreted broadly within a standardized tertiary carbonate ramp model biota can be used to define precise palaeobathymetric zones which have a predictive utility in palaeoenvironmental modelling especially where data are limited the carbonate ramp model of earlier authors has been elaborated by read 1982 and ramp formation occurs mostly in passive margin and extensional tectonic settings ramps are characterized by slope gradients of less than 1 degree and once established are conservative to change much use has been made of the ramp model for palaeozoic and mesozoic lithofacies modelling in contrast published work on cenozoic ramps is limited however tethyan ramps are particularly widespread and extend tens to hundreds of kilometres along strike and occupy tens of kilometres of slope many studies have dealt with cenozoic ramp associations and sequences e g pedley 1983 reiss hottinger 1984 purser 1973 and have demonstrated the diversity of biotal and sediment detail but without ascribing them to a ramp model biota were quick to adapt to the tertiary environments left vacant after the k t boundary extinction events new genera of foraminifera mollusca bryozoa and echinoder mata rapidly replaced the extinct forms in bursts of innovative opportunism codiacean algae rhodophyta and marine angiosperms were equally adaptive colonizers of the carbonate platforms novel biofacies associations were derived from

numerical modeling of acoustic tomography in the straits of florida sensitivity to bathymetry an acoustic model based on the split step parabolic equation technique is used to study the effects of irregularities in bathymetry on the transmission loss or equivalently sound energy distribution for continuous wave cw acoustic signals in particular contours of transmission loss in the range depth plane are predicted for the propagation of a 510 hz cw signal across the straits of florida between miami florida and bimini bahamas the predicted intensity contours exhibit recognizable energy bundles that correspond to actual ray bundles the stability of these bundles is studied as random bottom irregularities are introduced the distribution of acoustic energy is found to be insensitive to random variations in bottom bathymetry of up to 5 m rms the same model is used to investigate the feasibility of transport and depth averaged temperature measurements of the florida current by acoustic method energy contour plots are predicted for several source receiver geometries a system of five transceivers positioned to form two triangles sharing a common vertex in the eastern edge of the miami terrace is evaluated as a monitoring strategy

the role of decay and mineralization in the preservation of soft bodied fossils abstract fossil deposits that preserve soft bodied organisms provide critical evidence of the history of life usually only more decay resistant materials e g cuticles survive as organic remains as a result of selective preservation and subsequent diagenesis to more resistant biopolymers permineralization the permeation of tissues by mineralizing fluids may preserve remarkable detail particularly of plants however evidence of more labile tissues e g muscle normally requires the replication of their morphology by rapid in situ growth of minerals i e authigenic mineralization this process relies on the steep geochemical gradients generated by decay microbes the minerals involved and the level of detail preserved which may be subcellular depend on a number of factors including the nature of microbial activity and amount of decay availability of ions and the type of organism that is fossilized understanding these controls is essential to determining the conditions that favor exce

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

thiophenic biomarkers for palaeoenvironmental assessment and molecular stratigraphy reconstruction of ancient depositional environments is an important objective in the earth sciences the complex assemblages of organic molecules in sediments include compounds that can be related to known biochemicals produced by specific biota from well defined habitats1 3 and these chemical fossils are applied frequently to reconstruct palaeoenvironments especially in studies of organic and petroleum geochemistry and in chemical oceanography most of the compounds used in this way are hydro carbons2 4 although oxygenated for example alcohols acids and ketones and nitrogen containing for example porphyrins compounds have also been applied successfully1 2 here we report on the use of organic sulphur compounds as geochemical tools for palaeoenvironmental and stratigraphic assessment depth profiles of specific sulphur compounds related to certain organisms show significant variations reflecting changes both in sources of organic matter and in physical conditions such as salinity of the depositional environment in a number of cases these variations are not otherwise revealed by changes in lithology geochemical bulk data and or absolute and relative amounts of hydrocarbon biological markers moreover several organic sulphur compounds reveal the presence of unprecedented biochemicals in these palaeoenvironments

vascular plant biomarkers as proxies for palaeoflora and palaeoclimatic changes at the dogger malm transition of the paris basin france abstract vascular plant biomarkers are used here as a chemostratigraphic tool for tracing both palaeoflora and palaeoclimatic changes during the callovian and oxfordian in the paris basin the retene cadalene ratio shows low values in claystones from the middle callovian to the end of the lower oxfordian then increases drastically from the end of the lower oxfordian cordatum zone synchronously with the progressive development of the oxfordian carbonate platform the relative proportion of retene a conifer biomarker is strongly correlated with the abundance of some of its diagenetic precursors and with saturated diterpanes some of these are very common and abundant in the pinaceae family while specific markers for non pinaceae conifers are not detected thus the increase in the retene cadalene ratio around the cordatum zone reflects the rising proportion of pinaceae on the london brabant massif which was the nearest land from the locations studied as pinaceae show many morphological adaptations to dry climate compared to the other plants reported in the jurassic taphofloras of the paris basin their increasing proportion indicates an increasing aridity this climatic change is also supported by published geochemical palaeobiogeographical palynological palaeobotanical and mineralogical data a comparable increase in the relative proportion of retene was also described for the oxfordian of western australia which could be an argument for a worldwide increase in aridity at the end of the lower oxfordian

the pristane n heptadecane ratio as an indicator for recognition of hydrocarbon migration effects a simple scheme is proposed for type iii kerogen source rocks which uses pristane n heptadecane concentration ratios for recognition of hydrocarbon expulsion effects within the maturity interval 0 82 1 03 rm this scheme can be applied from gas chromatography data routinely obtained by most petroleum geochemistry studies in exploration exploration of this scheme to oil prone type ii source rocks appears very promising

terpenoid composition of fossil resins from western india new insights into the occurrence of resin producing trees in early paleogene equatorial rainforest of asia abstract the terpenoid composition of well preserved fresh and oxidized fossil resins ambers from early paleogene lignite bearing sequences of india have been examined using gas chromatography mass spectrometry for determining their botanical origin the samples were collected from two sedimentary basins viz barmer akli formation and bikaner nagaur palana formation western india the total extracts of the studied ambers are represented by hydronaphthalenes sesquiterpenoids and significant occurrence of diterpenoids such terpenoid distribution is typical for gymnosperm especially conifer derived sources the diterpenoids are comprised of majorly abietane phyllocladane kaurane pimarane isopimarane and podocarpane class compounds tertracyclic diterpenoids such as 18 norkauranes ent 16 h kaurane and 16 h phyllocladane and a rearranged tricyclic diterpenoid rosane are detected in the fossil resins from barmer basin the occurrence of tetracyclic diterpenoids and rosane together with 8 13 dimethyl 16 norpodocarpa 6 ene suggests that podocarpaceae family is the possible source of the ambers however chemotaxonomic assignment at family level for the fossil resin from bikaner nagaur basin is difficult due to the absence of source specific diterpenoids previous reports had documented the occurrence of angiosperm derived dammar resins from early paleogene sediments of india dutta et al 2009 rust et al 2010 the present study suggests that the early paleogene resins of the equatorial rainforests were not always represented by the dammar resins derived from dipterocarpaceae a family of angiosperm some of them were also contributed by the conifers

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