carbonate ion concentration in glacial age deep waters of the caribbean sea 1 on the basis of the whole foraminifera shell weights for g sacculifer and n dutertrei from caribbean cores it appears that the carbonate ion concentration of water at 1800 m depth in the open atlantic i e the depth of the caribbean sill was 14 mol kg greater during glacial time than during the holocene the sense of this difference is consistent with the observation that the 13c 12c ratio for benthic foraminifera from glacial age atlantic upper deep water was higher than that for their holocene equivalents it is also consistent with fragment to whole foraminifera results however as several questions regarding the assumptions involved in converting shell weights to paleocarbonate ion concentrations remain unanswered this reconstruction must be considered tentative critical in this regard are the assumptions that shell wall thicknesses were the same as today s at any given site during glacial time and that the 0 3 g per mol kg relationship between shell weight and carbonate ion concentration is applicable over the entire deep water column the records reported here reveal no evidence for an early holocene preservation event however that for core v28 122 documents a dissolution event close to the mis 5 4 boundary

conodont palaeobiogeography and thermal maturation in the caledonides conodont elements are important in biostratigraphy in palaeoenvironmental and palaeobiogeographical analyses and in assessing the thermal history of lower palaeozoic strata throughout the caledonian belt the differentiation of ordovician conodont faunas into the north atlantic and north american midcontinent provinces is not closely comparable with the provincial patterns shown by other faunal groups and does not relate clearly to criteria for recognizing continental separation across the iapetus ocean some species associations adapted to cool normal marine waters were able to cross the ocean at the time of its presumed maximum extent the colours of conodont elements reflect the thermal history of strata and can be used in studies of low grade metamorphism in s wales for example metamorphic temperatures indicated by conodont colour are too high to he accounted for by simple burial beneath the known stratigraphical overburden under normal heat flow conditions elsewhere conodont colour trends also serve to constrain and test models of metamorphism that involve sedimentary burial in subsiding basins tectonic burial under nappes or the thermal effects of intrusions

microdistribution of mg ca sr ca and ba ca ratios in pulleniatina obliquiloculata test by using a nanosims implication for the vital effect mechanism the mg ca ratio within foraminiferal calcareous tests shells is widely used to reconstruct past seawater temperature however recent studies reported that the organic components within a test affect the mg ca distribution in this study we have measured the mg ca sr ca and ba ca ratios within the planktonic foraminifera pulleniatina obliquiloculata by using a nanosims secondary ion mass spectrometer sims which has excellent spatial resolution 1 m and allows us to compare the distribution of chemical compositions with that of the organic components element compositions show banding distributions composed of alternately higher and lower values of those elemental ratios the mg ca ratios previously considered to be mainly controlled by calcification temperature show larger variations than the values expected from the seawater temperature at the habitat depth of p obliquiloculata comparison of the elemental distribution with the test microstructure reveals that the bands of high mg ca and sr ca ratios correspond with layers of the organic components such coincidence suggests that the organic components strongly affect the mg ca and sr ca ratios within a test in spite of the heterogeneous distribution temperature estimated from the averaged mg ca ratio within a test is consistent with seawater temperature at the habitat depth of p obliquiloculata indicating that whole mg ca ratio of foraminiferal test may be useful as paleotemperature proxy in contrast to the mg ca ratio the heterogenity in ba ca ratio which previously has been considered to be mainly controlled by the ambient seawater composition is not fully matched with the layers of the organic compositions although the organic components concentrate ba other unknown factors appear to also cause heterogenity in ba incorporation

irish carboniferous conodonts record maturation levels and the influence of tectonism igneous activity and mineralization organic maturation patterns in the lower carboniferous of ireland have been determined from conodont colour alteration indices cai for some 750 localities onshore ireland conodonts record increasing maturation in the carboniferous rocks from the oil window rocks of the north east southwards to the greenschist meta argillite regime of the munster basin in detail the caledonoid trend has a marked influence in the midlands whilst in the south sharp variations in cai are interpreted as being caused by thrusting of the variscan orogeny in the south east low maturities in the wexford half graben indicate that the region was shielded from orogenic stresses probably by the leinster massif igneous centres such as the carlingford complex and croghan hill produce local sites of increased palaeotemperature significant cai variations have also been noted in proximity to major base metal orebodies the cai results highlight north east ireland and the wexford half graben as areas with hydrocarbon potential

conodont thermal alteration patterns in palaeozoic rocks from belgium northern france and western germany in this paper thermal patterns based on conodont colour alteration indices cai have been studied in the devonian and carboniferous rocks from belgium northern france and western germany four maps with the exception of the southeastern rheinisches schiefergebirge have been compiled for the investigated area one for the eifelian and givetian a second for the frasnian another for the famennian and one for the tournaisian and visean conodonts have not been found in cambrian rocks from belgium and northern france and as they are scarce in the ordovician to lower devonian formations of this area it was impossible to integrate these cai data into an isograd map in germany in the eastern rheinisches schiefergebirge only a few cai values for the lower devonian strata are available in contrast to the ardennes where in general conodonts show cai values of 3 0 5 0 indices in areas adjacent to the anglo brabant massif e g in the western namur synclinorium and in the eifel hills range between 1 5 and 2 0 slightly higher values occur in the campine basin north of the anglo brabant massif by comparison with cai data from belgium conodont colour alteration indices from the same stratigraphic horizons in some areas of the northern and eastern rheinisches schiefergebirge are up to one index higher in most areas of the rheinisches schiefergebirge the level of metamorphism corresponds to the anchizone regional variations in cai data appear to be related to buried intrusions and associated hydrothermal activity in the southeastern rheinisches schiefergebirge cai data are not completely consistent but it is possible to discern an increase in coalification from the north to the south high index values in the southern rheinisches schiefergebirge are believed to result from regional metamorphism and heating related to numerous intrusive bodies

metamorphic fluids and transtension in the cantabrian mountains of northern spain an application of the conodont colour alteration index conodont colour alteration index cai values from upper paleozoic rocks in the cantabrian zone of northern spain show that temperatures during hercynian metamorphism locally exceeded 300 c various temperature domains have been defined which are generally separated by fundamental structures these domains do not correspond with the tripartite subdivision based on stratigraphic analysis the observed cai values of conodonts are in general agreement with the mineral paragenesis areas with high cai values display extensive alteration and mineralization and where cai values exceed 4 4 5 200 c slaty cleavage has developed the cantabrian zone is an area of very low grade metamorphism where peak conditions were reached in upper carboniferous to lower permian times the characteristics of the metamorphism and its spatial relationship with major faults suggest that fluids were the main source for regional heating and that fluid transport was focussed along crustal scale structural features the overall deformation regime in this part of the variscan orogen of western europe is interpreted to be large scale transtension this is in agreement with earlier proposed models for the formation of upper palaeozoic basins in this area

thermal metamorphism of the silurian strata of the oslo region assessed by conodont colour conodont elements from silurian limestones in the oslo region norway range from brown to grey samples from the south of the region contain black and grey conodonts indicative of high palaeotemperatures there is a general decrease in thermal metamorphism towards the north with the lowest palaeotemperatures recorded from toten ringsaker and parts of the ringerike district there is a close correlation between thermal metamorphism and the proximity of permian intrusions modified journal abstract

thermal maturation of the lower palaeozoic strata of northern greenland from conodont colour alteration index cai data implications for burial history and hydrocarbon exploration conodont colour alteration data for the lower palaeozoic strata of the north greenland carbonate platform indicate a pattern of increased thermal maturity northwards within the franklinian basin there is little variation in values through the canadian llandovery lower ordovician lower silurian interval at any given locality a simplified thermal model for the platform suggests that the predominant control of conodont colour alteration and thermal maturation was maximum depth of burial which occurred during the mid to late silurian a preliminary integrated scheme for conodont and organic thermal maturity indicators can be compiled from the data now available from north greenland

thrust related very low grade metamorphism in the marginal part of an orogenic wedge scandinavian caledonides the pattern and characteristics of thrust related very low grade metamorphism in the marginal part of an orogenic wedge have been investigated by combining a clay mineral crystallinity survey with detailed structural mapping of the thin skinned foreland thrust belt along the external part of the scandinavian caledonides this external part is composed of late neoproterozoic to ordovician sedimentary sequences of the autochthonous cover and lower allochthon which are overlain by the higher caledonian nappes middle and upper allochthonous units stages of the scandian phase of thrust wedge development are described which are related to the very low grade metamorphic history the initial stage involved the emplacement of cooled nappes belonging to the middle and upper allochthons with very low grade peak metamorphic conditions attained within the underlying lower allochthon cover sediments as they were progressively buried and deformed beneath the thrust wedge during this initial emplacement the isotherms are considered to have been undisturbed and dipping parallel to the wedge surface the following stages of wedge development consisted of extensive post metamorphic imbrication of the underthrusted cover sediments with a transition from basal accretion and uplift at the rear to accretion and forward propagation at the wedge s toe during accretion into the wedge the externally dipping isograd surfaces were extensively displaced from deeper levels toward higher tectonic horizons the last stage of wedge development considered here was characterized by late out of sequence thrusting with enhanced epizonal metamorphic grades developed in the vicinity of the fault zones which either resulted from further displacement of the isograds toward higher levels or from localized heating via intense fluid activity overall the pattern of metamorphic grade fabric relationships and physical calculations of heat transfer based on the geometry of the thrust wedge suggest that neither inverted temperature gradients nor shear heating were likely causes of the metamorphism in this flat lying part of the orogenic wedge the description of inverted very low grade metamorphic isograds in other marginal parts of the scandinavian caledonides which have been previously attributed to either the rapid emplacement of hot thrust nappes or the effects of dissipative shear heating are discussed in terms of variations in both the critical wedge geometry and its controlling boundary conditions

a first look at paleotemperature prospects from mg in coccolith carbonate cleaning techniques and culture measurements 1 although coccolith calcite is abundant in carbonate sediments it has not been previously utilized for mg ca paleothermometry cleaning experiments with synthetic composite samples reagent caco3 powder and organic matter from noncalcifying marine algae chlorella are used to evaluate which traditional and or novel cleaning methods permit us to recover the known carbonate mg ca ratio the most effective cleaning treatment causing the least effect on carbonate chemistry and most complete and rapid oxidation of algal organic matter was oxidation in an equal volume mixture of sodium hypochlorite 2 8 and hydrogen peroxide 30 however in some organic rich samples this method may not remove sufficient noncarbonate mg to permit precise determination of carbonate mg ca mg ca ratios in small culture samples may be determined precisely relative standard deviation of 0 65 using sector field inductively coupled plasma mass spectrometry measurements of mg ca in coccoliths from several species suggest that temperature may be an important control over mg partitioning in coccolith calcite although cleaning issues are likely to be an important limitation on paleoceanographic application

paleomagnetics of ringerike old red sandstone and related rocks southern norway implications for pre carboniferous separation of baltica and british terranes abstract paleomagnetic study of two stratigraphic sections of the upper silurian lower devonian ringerike sandstone oslo area norway indicate a straightforward multicomponent nrm for these rocks a lower temperature magnetization component gives a southwest and up reversed polarity in situ direction yields a negative fold test i e post folding at the 99 confidence level and is nearly identical to directions obtained from overlying permo carboniferous lavas a high temperature magnetization component exhibits both normal and reversed polarity directions passes a fold test at the 95 confidence level and is supported by a baked contact test which indicates a pre intrusion age of magnetization this characteristic high temperature component was successfully isolated in 79 samples from 19 sites within the ringerike succession results indicate a tilt corrected characteristic magnetic direction of declination 26 inclination 16 which is consistent with earlier work this direction corresponds to a time integrated paleopole position of 19 n latitude 164 longitude d p 4 8 d m 9 3 when compared to previous results from rocks of similar age from the british isles an approximately 20 latitudinal displacement between britain and baltica during late silurian early devonian time is suggested

inside story an x ray computed tomography method for assessing dissolution in the tests of planktonic foraminifera x ray computed tomography ct provides an insight into the progression of dissolution in the tests of planktonic foraminifera four species of foraminifera g ruber white g sacculifer n dutertrei and p obliquiloculata from pacific atlantic and indian ocean core top samples were examined by ct and sem inner chamber walls began to dissolve at co32 values of 12 14 mol kg close to the calcite saturation horizon dissolution and precipitation of calcite may occur simultaneously inner calcite of g sacculifer n dutertrei and p obliquiloculata from such sites appeared altered or replaced whereas outer crust calcite was dense with no pores unlike the other species there was no distinction between inner and outer calcite in ct scans of g ruber empty calcite crusts of n dutertrei and p obliquiloculata were most resistant to dissolution and were present in samples where co32 20 mol kg five stages of preservation were identified in ct scans and an empirical dissolution index xdx was established xdx appears to be insensitive to initial test mass mass loss in response to dissolution was similar between species and sites at 0 4 g mol kg we provide calibrations to estimate co32 and initial test mass from xdx

syn rift thermal structure and post rift evolution of the oslo rift southeast norway new constraints from fission track thermochronology abstract the permo carboniferous 240 305 ma oslo graben in southeast norway is a classical magmatic continental rift we present fission track ft data on apatites zircons and sphenes from the rift and surrounding areas in order to clarify its syn and post rift thermal evolution zircons and sphenes within the rift record ft ages of between 270 and 180 ma i e syn post rifting in contrast the precambrian basement surrounding the graben yields zircon ft sphene ft ages of 500 650 ma indicating that heating associated with rifting was focused inside the rift as a result of advective heat flow syn rift to early post rift temperatures reached 240 c at the present erosion level in the graben syn rift advective heating 260 270 ma was probably a result of large scale batholith intrusion post rift 180 220 ma heating seems to have occurred by hydrothermal circulation of high temperature 100 300 c fluids the ft data organic geochemical indicators and fluid inclusions suggest that hydrothermal circulation followed a highly complex pattern controlled by the tectonic and volcanic structure of the rift apatite ft ages and confined track length distributions reveal the post rift exhumation history of the area apatite ft ages are continuous within and outside the graben and decrease from triassic 200 240 ma in the southeast to jurassic 160 ma in the northwest indicating that post rift exhumation took place on a much larger scale than permian rifting modelling of apatite ft ages and track lengths suggests cooling denudation events in the triassic jurassic and neogene accounting for a total post permian erosion of 3 4 km triassic jurassic denudation coincides with the migration of rifting from the oslo skagerrak area to the north sea danish basin as revealed by offshore seismic data and caused destruction of the hydrothermal regime neogene uplift and erosion of the area is also supported by seismic evidence the inferred timing and amount of regional post rift erosion suggests that post rift subsidence and sedimentation within the oslo graben was minimal

core top calibration of mg ca in tropical foraminifera refining paleotemperature estimation 1 optimal use of mg ca as a paleotemperature proxy requires establishing calibrations for different species of foraminifera and quantifying the influence of dissolution to achieve this goal we have measured mg ca and 18o in a series of tropical and subtropical core tops including four depth transects the ceara rise the sierra leone rise and the rio grande plateau in the atlantic and the ontong java plateau in the pacific focusing on spinose mixed layer dwelling species globigerinoides ruber and globigerinoides sacculifer and nonspinose thermocline dwelling neogloboquadrina dutertrei shell mg ca in g sacculifer is 5 15 lower than in g ruber while n dutertrei mg ca is 49 55 lower than in g ruber this statistically significant offset has allowed us to establish different calibrations for each species multilinear regression analysis was used to develop calibration equations that include a correction term for the dissolution effect on mg ca in foraminiferal calcite presented in this paper are two sets of calibrations one set using core depth as a dissolution correction and another using co32 as a dissolution parameter the calibrations suggest that g ruber is the most accurate recorder of surface temperature while g sacculifer records temperatures below the surface at 20 30 m the depth habitat of n dutertrei is more uncertain owing to the wide range in habitat depths depending on hydrographic conditions but on average mg ca and 18o data suggest it is at 50 m of the three species n dutertrei is the most sensitive to dissolution up to 23 decrease in shell mg ca per km while g sacculifer is the most resistant

palaeomagnetic constraints upon the palaeogeographic position of the baltic shield in the ordovician the palaeomagnetic analysis of the ordovician limestones in southern scandinavia 75 sites has given the following results 1 in the southern part of the oslo region all ordovician sediments were remagnetized during the lower permian by a thermo chemical mechanism triggered by the emplacement of the permian volcanic and intrusive suite 2 in the northern part of the oslo region the upper caradoc mjosa limestone carries a high temperature component decl 53 incl 40 95 25 4 sites with corresponding palaeopole at 4 s 143 e 3 in southern sweden all lower ordovician orthoceras limestones sampled in dalarna narke scania vaster gotland oland and oster gotland display the same well defined southeast steep high temperature components leading to a palaeopole at 30 n 55 e a95 9 in areas with late palaeozoic volcanic activity scania vaster gotland this high temperature component is partially overprinted by a remagnetization associated with dolerite emplacement according to these results baltica was situated in temperate southern latitudes 50 s in the early ordovician and has drifted northwards at a latitudinal drift rate of 4 to 7 cm year to reach tropical latitudes 20 s by the late ordovician to late silurian this interpretation is in agreement with previous models based on the occurrence of ordovician reef structures and sheds new light on the early palaeozoic position of baltica relative to other continental blocks

differential preservation of primary isotopic signatures in silurian brachiopods from northern europe abstract isotopic and geochemical compositions of silurian calcitic brachiopod shells carbonate host rocks and calcite cements from two northern european sites with different diagenetic histories are compared gotland sweden oslo graben norway the sequence exposed on gotland is characterized by repeated synsedimentary subaerial exposure and meteoric influence but only insignificant thermal alteration during shallow burial diagenesis in contrast silurian sediments exposed in the oslo area show only few signs of early exposure but were severely affected by thermal alteration during burial of the succession the preservation potential of brachiopod shells in each basin is different most nonluminescent brachiopods from gotland show well preserved microstructures and trace element contents very similar to those of modern brachiopod shells tightly clustered isotope values of individual brachiopod populations do not suggest significant meteoric alteration of primary marine isotope signatures in contrast there is strong evidence that all brachiopod shells from the oslo area contain diagenetically altered 18o values alteration of norwegian brachiopods is not always reflected in their trace element contents and cathodoluminescence characteristics but under sem the shells often display corrosion and recrystallization scattered oxygen isotope values in nonluminescent brachiopods 18o 18 to 5 5o oo together with low 18o values the case study from the oslo graben demonstrates that high fluid rock ratios and thermal overprinting during burial diagenesis may result in pervasive diagenetic alteration of 18o values in nonluminescent brachiopod shells this alteration can be detected by combined petrographic and geochemical investigations on brachiopod shells diagenetic cements and carbonate host rocks brachiopods from deeply buried and hydrothermally altered sites should not be used for deciphering marine 18o signals however the data presented here argue against a general rejection of lower paleozoic brachiopods as indicators of marine isotope signatures

calibration of mg ca thermometry in planktonic foraminifera from a sediment trap time series 1 paired mg ca and 18o measurements on planktonic foraminiferal species g ruber white g ruber pink g sacculifer g conglobatus g aequilateralis o universa n dutertrei p obliquiloculata g inflata g truncatulinoides g hirsuta and g crassaformis from a 6 year sediment trap time series in the sargasso sea were used to define the sensitivity of foraminiferal mg ca to calcification temperature habitat depths and calcification temperatures were estimated from comparison of 18o of foraminifera with equilibrium calcite based on historical temperature and salinity data when considered together mg ca mmol mol of all species except two show a significant r 0 93 relationship with temperature t c of the form mg ca 0 38 0 02 exp 0 090 0 003 t equivalent to a 9 0 0 3 change in mg ca for a 1 c change in temperature small differences exist in calibrations between species and between different size fractions of the same species o universa and g aequilateralis have higher mg ca than other species and in general data can be best described with the same temperature sensitivity for all species and pre exponential constants in the sequence o universa g aequilateralis g bulloides g ruber g sacculifer other species this approach gives an accuracy of 1 2 c in the estimation of calcification temperature the 9 sensitivity to temperature is similar to published studies from culture and core top calibrations but differences exist from some literature values of pre exponential constants different cleaning methodologies and artefacts of core top dissolution are probably implicated and perhaps environmental factors yet understood planktonic foraminiferal mg ca temperature estimates can be used for reconstructing surface temperatures and mixed and thermocline temperatures using g ruber pink g ruber white g sacculifer n dutertrei p obliquiloculata etc the existence of a single mg thermometry equation is valuable for extinct species although use of species specific equations will where statistically significant provide more accurate evaluation of mg ca paleotemperature

the influence of permeability on compressional wave velocity in marine sediments to investigate the effect of permeability on the propagation of seismo acoustic waves through marine sediments a theoretical model based on biot s equations is established which relates the compressional wave velocity measured at a fixed frequency to computed velocities at zero and infinite frequencies in terms of sediment porosity and permeability the model is examined experimentally in a standard soil mechanics consolidation test itself dependent among other things on sediment porosity and permeability which has been modified to include measurements of compressional wave velocity at l mhz and shear wave velocity at 5 khz this test allows the elastic modulus of the sediment frame to be assessed under different load conditions simultaneous with the velocity determinations from a number of tests on different samples five samples are chosen to typify the range of sediment sizes the results show that the difference between the measured velocity at l mhz and the model derived velocity at zero frequency increases with increasing particle size from clays to fine sand with decreasing porosity and with increasing permeability for sediments coarser than fine sand the simple model breaks down possibly because of the dominance of scattering diffraction effects at the high frequency of the experiment within this limitation themore model seems satisfactory to offer a capability of predicting the permeability of a sea floor sediment to an order of magnitude by the in situ measurement of seismic velocities over a wide range of frequencies the prediction process requires a good in situ determination of sediment porosity such as that offered by electrical formation factor measurements less

radiocarbon age offsets of foraminifera resulting from differential dissolution and fragmentation within the sedimentary bioturbated zone 1 shells of coexisting species of planktonic foraminifera from the ontong java plateau reveal radiocarbon age offsets of up to 2200 years similar offsets are found between fragments and whole shells of single species steady state modelling of dissolution and bioturbation within the sedimentary mixed layer predicts age differences of up to several kiloyears due to the interplay between differential dissolution and fragmentation of foraminifer shells and bioturbation the observation that fragile foraminiferal shells are systematically older than those of more robust species is more difficult to explain mechanisms of chemical erosion interface dissolution and sediment redistribution are all apparently unable to explain this phenomenon a possible solution is presented in which a particular species may be represented by two distinct classes of shells which are more or less robust in this case differential dissolution and fragmentation causes an increase in the mean age as the fragile class contributes less to the remaining intact shells this study highlights the vulnerability of low sedimentation rate cores to the effects of dissolution and bioturbation

conodont geothermometry and tectonic overburden in the northernmost east greenland caledonides kronprins christian land lies at the northernmost limit of the east greenland caledonides and may be divided into four main tracts foreland parautochthon thin skinned thrust sheets containing neoproterozoic sediments and thick skinned thrust sheets of crystalline basement the eastern part of the foreland and the parautochthon are composed of ordovician silurian shelf carbonates overlain by llandovery lower wenlock turbidites deposited at the southern margin of the franklinian basin deformation of the parautochthon occurred beneath a major detachment the vandredalen thrust with neoproterozoic sediments of the rivieradal group lying in the hanging wall the rivieradal group was deposited in an e facing half graben and was displaced westwards across its rift shoulders during caledonian thrusting extensive sampling for conodonts has been carried out within the lower palaeozoic rocks of the foreland and parautochthon in order to increase the precision of structural interpretations and to provide data on maximum burial temperature and in turn the thickness of overburden in contrast to earlier studies conodont colour alteration indices cai show a gradual and continuous increase from cai 3 in the eastern part of the foreland to cai 5 in the easternmost parts of the parautochthon the isopleths are not disrupted or truncated by thrusting as previously suspected indicating that the heating is not attributable to pre thrusting stratigraphic overburden furthermore considerations of the regional geology indicate that there was no significant accumulation of sedimentary overburden in post caledonian time the predominant component is thus considered to be loading by thrust sheets modelling of the overburden thickness suggests that prior to erosion it increased from 3 9 km cai 3 in the easternmost foreland to a maximum of 12 5 km beneath the vandredalen thrust sheet in the easternmost part of the area providing constraints for restoring cross sections across the orogen

recent advances in coalification studies and their application to geology abstract recent advances in coalification studies since 1970 are reported concerning microscopic methods causes of coalification the coalification process as such and application to geology the degree of coalification rank is mostly determined on the basis of vitrinite reflectance measured on finely dispersed material in rocks for rocks bare of vitrinite other microscopic methods are used such as fluorescence properties of liptinites and graptolite reflectance under incident light or coloration of microfossils like palynomorphs and conodonts in transmitted light the validity of the various methods is discussed maximum rock temperature and its duration are the main causes of chemical coalification reactions heating rates during subsidence influence the attainment of rank equilibrium contact metamorphic coals and natural cokes formed from bituminous coals are characterized by a relatively high reflectance and anisotropy strong frictional heat may cause local increase of rank adjacent to thrust planes graphitization is thermodynamically not possible in nature without pressure and shearing confining pressure retards the chemical coalification reactions tectonic stress especially shearing promotes the increase of maximum reflectance and of anisotropy it commonly leads to bi axial optical properties instead of the more typical uni axial negative geometry of vitrinite in undisturbed coal seams bi axial optical properties are common for vitrinite inclusions in clastic rocks on the basis of combined fluorescence microscopical and geochemical studies bituminization has been recognized as the characteristic part of coalification in the range between sub bituminous and bituminous coal it is characterized by the generation of petroleum like substances which enable the coal to soften and to agglomerate during carbonization hydrogenation properties are favoured by the bituminization process the different liptinite macerals behave differently during coalification and pass coalification jumps at different rank stages a considerable part of total inertinites is formed during early coalification brown coal to sub bituminous coal stage as rank inertinite this new knowledge appears to become important in relation to hydrocarbon exploration diagenetic methane some examples for the application of coalification studies to geology refer to vitrinite reflectance as an indicator of rock diagenesis and metamorphism palaeogeographical and structural history palaeogeothermics and hydrocarbon exploration large scale areal coalification studies in foredeeps and backdeeps of ancient and recent orogens suggest estimations of crustal thicknesses and relations to plate tectonics