validation of fracture data recognition in rock masses by automated plane detection in 3d point clouds abstract this paper presents 1 an automated method to extract planes and their spatial orientation directly from 3d point clouds followed by 2 extensive validation tests accompanied by thorough statistical analysis and 3 a fracture intensity calculation on automatically segmented planes for the plane extraction a region growing segmentation algorithm controlled by several input parameters is applied to a point cloud of a granite outcrop within its complex surface shape more than 1000 compass measurements were conducted for validation in addition digitally handpicked planes in the software virtual reality geological studio vrgs were used for single plane comparison in a second test site we performed fracture intensity calculation in petrel based on results of the segmentation algorithm on mechanical layers of a clastic sedimentary succession the comparison of automated segmentation results and compass measurements of three different plane sets shows a deviation of 0 70 2 00 while the mean single plane divergence amounts to 4 97 hence this study presents a fast precise and highly adaptable automated plane detection method which is reproducible transparent objective and provides increased accuracy in outcrops with rough and complex surfaces moreover output formats of spatial orientation and location of planes are designed for simple handling in other workflows and software

terrestrial laser scanning of rock slope instabilities this manuscript presents a review on the application of a remote sensing technique terrestrial laser scanning tls to a well known topic rock slope characterization and monitoring although the number of publications on the use of tls in rock slope studies has rapidly increased in the last 5 10 years little effort has been made to review the key developments establish a code of best practice and unify future research approaches the acquisition of dense 3d terrain information with high accuracy high data acquisition speed and increasingly efficient post processing workflows is helping to better quantify key parameters of rock slope instabilities across spatial and temporal scales ranging from cubic decimetres to millions of cubic metres and from hours to years respectively key insights into the use of tls in rock slope investigations include a the capability of remotely obtaining the orientation of slope discontinuities which constitutes a great step forward in rock mechanics b the possibility to monitor rock slopes which allows not only the accurate quantification of rockfall rates across wide areas but also the spatio temporal modelling of rock slope deformation with an unprecedented level of detail studying rock slopes using tls presents a series of key challenges from accounting for the fractal character of rock surface to detecting the precursory deformation that may help in the future prediction of rock failures further investigation on the development of new algorithms for point cloud filtering segmentation feature extraction deformation tracking and change detection will significantly improve our understanding on how rock slopes behave and evolve perspectives include the use of new 3d sensing devices and the adaptation of techniques and methods recently developed in other disciplines as robotics and 3d computer vision to rock slope instabilities research

biomarker signatures of upper cretaceous latrobe group hydrocarbon source rocks gippsland basin australia distribution and palaeoenvironment significance of aliphatic hydrocarbons abstract upper cretaceous maastrichtian and campanian hydrocarbon source rocks from the latrobe group gippsland basin australia have been analysed using gas chromatography mass spectrometry gc ms in order to understand their geochemical characteristics and to reconstruct palaeovegetation and palaeoclimate changes n alkanes ranging from c10 to c37 dominate the aliphatic hydrocarbons in the rock extracts both the carbon preference index and the odd to even predominance values of n alkanes are higher than 1 0 suggesting an input from terrigenous higher plants low wax indices mostly 3 0 a low gammacerane index

automatic characterization of rock mass discontinuities using 3d point clouds abstract direct contact measurements for rock mass discontinuities are generally difficult to perform time consuming biased and often dangerous this paper presents an automatic characterization method for rock mass discontinuities that uses 3d point clouds which can be obtained through non contact measuring techniques such as photogrammetry and light detection and ranging lidar in this method five discontinuity parameters namely the orientation trace spacing roughness and aperture are extracted automatically the overall methodology is as follows 1 orientation is determined by using an improved k means clustering method 2 trace segments are detected by using the normal tensor voting theory and four post processing techniques are employed to compute the trace length 3 spacing is calculated by plotting virtual normal scan lines on the projected traces 4 roughness is evaluated by the correlation between the joint roughness coefficient jrc and the root mean square of the discontinuity surface profile and 5 aperture is obtained by computing the average minimum width based on sub pixel edge detection the proposed method was applied to a drill and blast rock tunnel where the extracted discontinuity parameters were used to calculate the rock mass rating rmr value and geological strength index gsi of the rock mass the application results showed that photogrammetry was more objective and efficient for acquiring rock mass discontinuity information and that it could be used as a potential alternative to the traditional discontinuity mapping method

relationship between petroleum composition and depositional environment of petroleum source rocks crude oils of nonmarine source can be distinguished from those of marine shale source and from oils originating in marine carbonate sequences by using a battery of geochemical parameters as demonstrated with a sample suite of nearly 40 oils a novel parameter based on the presence of c30 steranes in the oil was found to be a definitive indication of a contribution to the source from marine derived organic matter a second novel parameter based on monoaromatized steroid distributions was effective in helping to distinguish nonmarine from marine crudes and can be used to gauge relative amounts of higher plant input to oils within a given basin sterane distributions were similarly useful for detecting higher plant input but were less effective than monoaromatize steroid distributions for making marine versus nonmarine distinctions concentrations of high molecular weight paraffin can also be effective nonmarine indicators but are influenced by maturation and biodegradation processes certain algal derived nonmarine oils may show little high molecular weight paraffin response oils from carbonate sources with a few exceptions can be distinguished by having low pristane phytane ratios low carbon preference indexes and high sulfur contents gammacerane indexes and carbon isotope ratios of the whole crude are not effective in distinguishing these types of environmental differences on a global basis

numerical investigation into strength and deformability of veined rock mass abstract veined rock masses can be found in porphyry copper deposits like at the el teniente mine in chile rock masses with cemented joints or veins cannot be accurately represented using the methods commonly applied to predict the deformability and strength of jointed rock masses laboratory tests on veined rock andesite from the el teniente mine have shown that the veins control the fracturing process and strength in this work the behavior of veined rock was studied using a numerical model built in the finite element software abaqus in this analysis the rock mass was modeled as an assemblage of blocks bonded by layers representing the intact rock and veins respectively uniaxial compression tests on veined core size specimens were simulated and their results compared to experimental data the results show good agreement with the experiments in terms of strength stiffness and mode of failure after this a veined rock mass volume was modeled using the orientation of mapped and post processed discontinuities as input simulations of uniaxial and triaxial tests were performed on the modeled veined rock mass the observed failure mode confirms experimental results showing that at low confinement the failure is concentrated in the veins and the rupture of intact rock becomes significant at higher confinement the obtained strength envelope of the veined rock mass is non linear and its shape is independent of the strength of the intact rock however the hoek brown criterion did not fit the results the residual strength of the veined rock approximated the residual strength of the intact rock agreeing with previously reported observations in jointed rock

quantifying the effects of vein mineralogy thickness and orientation on the strength of intact veined rock abstract the presence of veins in the rock matrix influences the behaviour of a rock this results in a behaviour that is distinct from intact rock without any veins and structure and from jointed rock in this context intact veined rock is a rock containing mineral veins and no joints this paper investigates the influence of vein mineralogy thickness and orientation on the strength of intact veined andesite from the el teniente mine this investigation has focused on a comprehensive vein characterization and analyses of the results of triaxial compression experiments in a comprehensive laboratory investigation it was demonstrated that the peak strength of intact veined rock specimens was strongly influenced by the orientations of individual veins whereby vein mineralogy and thickness had a lesser role a further analysis of the mineral composition of the intact veined rock specimens following a series of triaxial tests revealed a more dominant influence of the mineral composition of the veins it was shown that rock specimens dominated by veins containing 4 attained significantly lower peak strengths than specimens where the average content of hard minerals exceeded 60 of the vein infill analyses of the mobilised shear strength of individual veins demonstrated a strong correlation between the presence of hard minerals and the strength of individual veins in the rock specimens this relationship was stronger when the vein volumetric content of hard minerals was

discontinuity spacing analysis in rock masses using 3d point clouds abstract the complete characterization of rock masses implies the acquisition of information of both the materials which compose the rock mass and the discontinuities which divide the outcrop recent advances in the use of remote sensing techniques such as light detection and ranging lidar allow the accurate and dense acquisition of 3d information that can be used for the characterization of discontinuities this work presents a novel methodology which allows the calculation of the normal spacing of persistent and non persistent discontinuity sets using 3d point cloud datasets considering the three dimensional relationships between clusters this approach requires that the 3d dataset has been previously classified this implies that discontinuity sets are previously extracted every single point is labeled with its corresponding discontinuity set and every exposed planar surface is analytically calculated then for each discontinuity set the method calculates the normal spacing between an exposed plane and its nearest one considering 3d space relationship this link between planes is obtained calculating for every point its nearest point member of the same discontinuity set which provides its nearest plane this allows calculating the normal spacing for every plane finally the normal spacing is calculated as the mean value of all the normal spacings for each discontinuity set the methodology is validated through three cases of study using synthetic data and 3d laser scanning datasets the first case illustrates the fundamentals and the performance of the proposed methodology the second and the third cases of study correspond to two rock slopes for which datasets were acquired using a 3d laser scanner the second case study has shown that results obtained from the traditional and the proposed approaches are reasonably similar nevertheless a discrepancy between both approaches has been found when the exposed planes members of a discontinuity set were hard to identify and when the planes pairing was difficult to establish during the fieldwork campaign the third case study also has evidenced that when the number of identified exposed planes is high the calculated normal spacing using the proposed approach is minor than those using the traditional approach

improvements to field and remote sensing methods for mapping discontinuity persistence and intact rock bridges in rock slopes abstract discontinuity persistence and intact rock bridges are critical factors that influence the stability of rock slopes persistence influences the extent of pre existing potential failure surfaces and intact rock bridges can add cohesion and tensile strength to an incipient failure surface which must be destroyed before slope failure can occur despite continued research and improvements in mapping technology computing power and numerical modelling codes there is no standard recommended methodology for field characterisation of intact rock bridges or their incorporation into stability analysis we use observations from remote sensing and field mapping investigations at three open pit mines and one natural rock slope to recommend improvements to field and remote sensing methods for mapping discontinuity persistence and intact rock bridges in rock slopes we apply a fracture network engineering approach to discontinuity trace mapping using new intensity factors to describe intact rock bridge trace intensity r 21 and blast induced fracture intensity b 21 we emphasize the importance of multi scale characterisation of discontinuity persistence and rock bridges in rock slopes and we distinguish between different classes of intact rock bridges based on scale and geometry with particular attention given to the distinction between laboratory sample scale intact rock bridges on incipient discontinuities and larger rock mass bridges which represent metre or larger scale intervals of fractured rock mass that may exist between very high persistence joints and faults

the effects of thermal maturity on distributions of dimethylnaphthalenes and trimethylnaphthalenes in some ancient sediments and petroleums abstract the distributions of di and trimethylnaphthalenes in two sedimentary sequences from western australia have been examined by capillary gas chromatography and combined gas chromatography mass spectrometry a general decrease was observed in the relative proportions of dimethylnaphthalenes and trimethylnaphthalenes with increasing thermal maturity similar trends were also observed for six crude oils which have very different ratios of ethylcholestane epimers indicating very different thermal histories these results suggest that changes in the relative abundances of certain methyl substituted naphthalenes may be useful indicators of thermal maturity of sedimentary organic matter and the use of a number of isomer ratios is illustrated

fault spacing in the el teniente mine central chile evidence for nonfractal fault geometry we utilize the excellent rock exposure provided by the network of mining tunnels in el teniente mine central chile to test the applicability of fractal fault spacing laws to a 2 km 3 km 1 3 km body of crystalline rock in an andean shear zone fractal spacing laws can be particularly useful because they allow prediction of fault spacing at unsampled scales because of the restrictions of tunnel geometry in the mine we use only scanline one dimensional analyses the large number of parallel tunnels allows us to assess the consistency of one dimensional scanline samples over a two dimensional area we use two methods 1 an interval counting technique and 2 standard cumulative statistics to test the hypothesis of fractal fault geometry in the shear zone the interval counting method produces deceptively good fits to a fractal distribution in fact by analyzing the residuals and differential slopes of interval counting and cumulative statistical plots and by comparison with synthetic fractal negative exponential and log normal distribution data we conclude that a negative exponential distribution best describes fault spatial distribution at the mine we present three possible explanations for the negative exponential spacing distribution 1 the rock body is at the earliest stage in a deformational path that will produce varying spacing distributions as deformation proceeds 2 the spacing distribution is inherited through joint reactivation and 3 the present spacing distribution is the result of a superposition of two spacing distributions each of which is not necessarily negative exponential additionally we attempt to use the deviation of mean spacings in parallel scanlines after wu and pollard 1995 to further classify deformational maturity we show that this method cannot be used to compare population development in faults which follow a negative exponential spacing distribution because of the negative exponential s equivalence of mean and standard deviation instead we use a relative measure of parallel scanline deviation to compare regions the distinctly smaller standard deviation of mean spacings in one region the t3 isla region may be a signature of increased local finite strain accumulation

assessing the maturity of oil trapped in fluid inclusions using molecular geochemistry data and visually determined fluorescence colours abstract the thermal maturity of oils extracted from inclusions and the fluorescence colours of oil bearing fluid inclusions have been measured in 36 sandstone samples from australasian oil fields the inclusion oils were analysed using an off line crushing technique followed by gc ms a maturity assessment was made for each inclusion oil using 25 molecular maturity ratios including a newly defined dimethyldibenzothiophene ratio dmdr each inclusion oil was placed in one of 4 maturity brackets approximately equivalent to early mid peak and post oil generation windows the fluorescence colours of oil inclusions were visually discriminated into blue white and yellow plus orange and their proportions estimated using point counting techniques sixteen samples have 85 of oil inclusions with blue fluorescence whilst other samples have more variable fluorescence colours one sample has 100 of oil inclusions with yellow plus orange fluorescence the results show that samples containing mainly blue fluorescing oil inclusions have thermal maturities anywhere within the oil window in particular the molecular geochemical data strongly suggests that oil inclusions with blue fluorescence can have relatively low maturities calculated reflectance

polycyclic aromatic hydrocarbons in ancient sediments and their relationships to palaeoclimate combustion derived and land plant derived polycyclic aromatic hydrocarbons pahs have been investigated for an upper triassic to middle jurassic sedimentary sequence from the northern carnarvon basin western australia the former included fluoranthene pyrene benzofluoranthenes benzo e pyrene and benzo a pyrene and the latter included retene cadalene and simonellite combustion derived pahs are most abundant in the upper triassic and late lower jurassic sediments the abundances of land plant derived markers all maximise in the upper part of the lower jurassic section but vary independently of one another through time the changes in the relative abundances of these markers have been related to the variation of regional climatic conditions especially the changes in humidity and seasonality during the late triassic to middle jurassic times

relationship between rank and composition of aromatic hydrocarbons for coals of different origins distributions of di and tricyclic aromatics were determined for upper carboniferous to oligocene coals of various origins in addition to upper carboniferous ruhr coals wealden lower creataceous coals from north west germany lower cretaceous coals from western canada and tertiary coals from japan and colombia were studied the coals ranged from sub bituminous to anthracite in rank and showed vitrinite reflectance from 0 4 to 4 9 rm the previously established relationship between the rank of coal in terms of vitrinite reflectance and the distribution patterns of individual aromatic hydrocarbon isomers has been verified and refined it is demonstrated how the above relationships can be used to calculate vitrinite reflectance from the methylphenanthrene index mpi 1 the chemical rank levels of coals can now be defined in terms of the calculated vitrinite reflectance rc

peculiarities of salt lake sediments as potential source rocks in china abstract hypersaline lake sediments are widely distributed in china and can be good sources for petroleum the palaeogene sediments of the jianghan basin in eastern china are a typical example composed of salt lake evaporite clastic facies in fault subsided basins their organic matter is variable but is dominated by type ii kerogen the biological marker characteristics of core extracts and oils from the jianghan basin include i low oep values for n alkanes and occasionally an even odd predominance ii a high concentration of phytane iii a relatively high gammacerane 17 h 21 h hopane ratio and iv abundant mainly nickel porphyrins sample guang 33 k 33 is typical of the immature oils found in the jianghan basin geological and geochemical data both indicate that it was generated from source rocks in the maturity range r 0 0 45 0 55 its characteristics are similar to those of immature source rocks with high concentrations of phytane steranes triterpanes and nickel porphyrins and for an oil extremely low values for molecular parameters of maturity such as c 29 20s 20s 20r 14 h 17 h steranes c 32 22s 22s 22r 17 h 21 h hopanes and dpep dpep etio porphyrins

physical model simulation of shallow openings in jointed rock mass under static and cyclic loadings abstract physical model simulations have been performed to determine the effects of depth joint spacing and orientation on the maximum unsupported span of shallow underground openings under static and cyclic loads cubical and rectangular blocks of phu phan sandstone are arranged in a vertical test frame to simulate a two dimensional representation of single rectangular openings in rock mass with two mutually perpendicular joint sets results indicate that the normalized maximum span w sv rapidly increases with the normalized depth d sh and tends to approach a certain limit for each joint spacing ratio sv sh the maximum span increases with decreasing sv sh ratio under sv sh condition increasing the joint angles from 0 to 45 reduces the maximum span by about 20 at shallow depths the acceleration of 0 225 g can reduce the maximum span by up to 50 the impact of the cyclic loads however reduces as the depth increases the test results under both static and cyclic loadings compare reasonably well with those calculated from discrete element analyses using the udec code

a geostatistical approach to estimating the parameters of a 3d cox boolean discrete fracture network from 1d and 2d sampling observations abstract this work addresses the problem of parameter inference in the cox boolean discrete fracture network model in which the fractures are represented by flat discs with random orientations and diameters that are centered at the points of a doubly stochastic poisson process or cox process since the distributions of the fracture orientations and fracture diameters can be estimated from information of borehole and areal surveys the focus is given to the distribution of the potential field of the cox process which measures the average number of fracture centers per unit volume to this end a relationship between the distributions of fracture diameter fracture intensity mean fractured surface per unit volume and potential field over a large block support is established and relationships between the moments of these distributions are derived in practice the moments of the fracture intensity at a point support can be inferred from borehole information and upscaled to larger block supports using geostatistical tools the moments of the potential field over these block supports can be deduced with the previous relationships which in turn allows estimation of the distribution and spatial continuity of the point support potential field under a given parametric model the validity and applicability of the concepts are demonstrated on synthetic case studies and a workflow to fit a cox boolean discrete fracture network model on the basis of information of borehole and areal surveys is provided

spatial modeling of discontinuity intensity from borehole observations at el teniente mine chile abstract this work addresses the problem of predicting the discontinuity intensity p32 discontinuity area per unit volume of rock mass in space and of quantifying the uncertainty in the true p32 values using information from observed discontinuities intersecting boreholes this problem is relevant in various fields of engineering including mining applications hydrocarbon extraction groundwater modeling and civil works the main idea is to calculate experimental p32 values for borehole segments composites based on a terzaghi weighting of the discontinuities that intersect the boreholes a validation exercise performed on simulated discrete fracture networks demonstrates that the calculated p32 values provide unbiased predictions of the true p32 at both global and local scales and can therefore be used as experimental data for spatial interpolation purposes by using geostatistical simulation techniques the spatial prediction of the p32 and the corresponding measures of uncertainty can be obtained on a block by block basis this methodology is applied to a data set from the el teniente copper mine codelco chile the objective is to map the expected values of the intensity of stockwork veins with a weak infill mineral assemblage and a typical thickness greater than 1 mm which are referred to as weak veins confidence limits on this intensity and its probability of exceeding given critical values are also estimated the quality of the prediction and of the uncertainty quantification is checked by leave one out cross validation the resulting confidence limits and probability maps can be used as indicators to define geotechnical domains in the rock mass

comparison of methods for estimating fracture size and intensity applied to aiguille marbree mont blanc abstract this article presents a multidisciplinary research devoted to correlate estimation of the rock mass characteristics with parameters and features obtained by the use of digital photography the data obtained from remote slope analysis are then undertaken to a statistical analysis of discrete data samples comparing different survey areas in terms of shape and dimension of the sampling window the method is developed by an application to the north rock face of the aiguilles marbrees mont blanc this slope was chosen as case of study since it represents an important high mountain location from the environmental and touristic point of view where the severe working condition led to the application of innovative methodology this site is monitored by a local authority fondazione montagna sicura devoted to the territory safe control since a rock fall of considerable size occurred in september 2007 after a photogrammetric survey an orthophotograph has been created circular windows have been materialized on the orthophotograph to perform area sampling statistical analysis of the obtained data enables us to calculate parameters and estimators for rock mass classification

organic facies and maturation of jurassic cretaceous rocks and possible oil source rock correlation based on pyrolysis of asphaltenes scotian basin canada abstract this paper establishes source rock characterization and oil oil and oil source rock correlations of selected organic rich shale source rocks and selected light oils and condensates from jurassic and cretaceous formations of the scotian basin multiple source rocks of kerogen types iia oil prone iia iib oil and condensate prone iib condensate and gas prone iii gas prone and iv nonsource are identified in various stratigraphic horizons vitrinite reflectance and t inmax data indicate variable maturation histories in different parts of the basin which are related to differences in lithology related heat conductivity and the presence of older sediments closer to areas of rifting multiple linear regression and cluster analyses of aromatic hydrocarbon ratios reveal two oil families some kerogen type iib rock extracts match many of the light oil and condensates in terms of the aromatic hydrocarbon distributions a second family of oils could not be correlated with any of the analyzed source rock extracts pyrolysis gas chromatography of asphaltenes from the cohasset a 52 and sable island 3h 58 wells are significantly different in n alkane aromatics and phenol content the asphaltene pyrolyzates of samples from venture b 52 and s desbarres o 76 have a high aromatic content low content of n alkanes and high phenol values s desbarres which is typical of a terrestial source they correlate well with one another and also with sable island light oil the n triumph g 43 whole rock and extract asphaltene pyrolyzates are dominated by normal hydrocarbons with aromatic phenolic and thiophenic compounds in low concentrations suggesting an algal source algal type organic matter may have made a contribution to the cohasset petroleum as its asphaltene pyrolyzate is also dominated by normal hydrocarbons

close range terrestrial digital photogrammetry and terrestrial laser scanning for discontinuity characterization on rock cuts this paper reviews the application of close range terrestrial digital photogrammetry and terrestrial laser scanning for discontinuity characterization on rock cuts terrestrial remote sensing techniques are being increasingly used as a complement to traditional scanline and window mapping methods they provide more comprehensive information on rock cuts allow surveying of inaccessible outcrops and increase user safety selected case studies are used to estimate the accuracy of several 3d model registration approaches and the most time effort and cost effective methods are highlighted it is shown that simple registration networks are able to provide adequate measurement of discontinuity orientation for engineering purposes the case studies presented also illustrate the effects of sampling bias and limitations related to discontinuity characterization using remote sensing techniques vertical orientation bias and occlusion can be of particular concern when persistent discontinuities dip at the same angle as the camera scanner line of sight major advantages of the techniques are presented illustrating how terrestrial remote sensing techniques provide rapid spatial measurements of discontinuity location orientation and curvature and are well suited to the quantification of persistence magnitudes greater than 3 m

fracture size estimation using data from multiple boreholes abstract the size of a fracture within a rock mass can be obtained using data sampled from boreholes or exposed surfaces in this study fracture sizes are estimated using data from multiple boreholes the fractures are assumed to be elliptical all having the same aspect ratio but not necessarily occurring parallel to each other formulae for estimating the mean and standard deviation of the characteristic fracture size are developed by considering the number of intersections between the fractures and the boreholes a method is proposed to infer the probability density function of the fracture size from the number of fractures which is obtained by random sampling of fractures in adjacent boreholes the fracture distribution is assumed to follow the form of a fractal exponential or lognormal distribution the performance of the method is validated using monte carlo simulations with different inputs of size distribution fracture density orientation and mean fracture size

laser scanning based recognition of rotational movements on a deep seated gravitational instability the cinque torri case north eastern italian alps abstract the cinque torri group cortina d ampezzo italy is an articulated system of unstable carbonatic rock monoliths located in a very important tourism area and therefore characterized by a significant risk the instability phenomena involved represent an example of lateral spreading developed over a larger deep seated gravitational slope deformation dsgsd area after the recent fall of a monolith of more than 10 000 m 3 a scientific study was initiated to monitor the more unstable sectors and to characterize the past movements as a fundamental tool for predicting future movements and hazard assessment to achieve greater insight on the ongoing lateral spreading process a method for a quantitative analysis of rotational movements associated with the lateral spreading has been developed applied and validated the method is based on i detailed geometrical characterization of the area by means of laser scanner techniques ii recognition of the discontinuity sets and definition of a reference frame for each set iii correlation between the obtained reference frames related to a specific sector and a stable external reference frame and iv determination of the 3d rotations in terms of euler angles to describe the present settlement of the cinque torri system with respect to the surrounding stable areas in this way significant information on the processes involved in the fragmentation and spreading of a former dolomitic plateau into different rock cliffs has been gained the method is suitable to be applied to similar case studies

geochemical evaluation of aliphatic and aromatic hydrocarbons in palaeogene source rocks from the latrobe group gippsland basin australia abstract twenty seven hydrocarbon source rocks from the proteacidites asperopolus malvacipollis diversus and lygistepollenites balmei biozones palaeogene latrobe group in the gippsland basin were analysed using gas chromatography mass spectrometry based on the molecular geochemistry of the aliphatic and aromatic fractions together with bulk geochemical data including rock eval pyrolysis and total organic carbon contents the thermal maturity palaeoenvironments and organic matter source of these palaeogene samples were systematically evaluated the results provide a useful comparison with those from upper cretaceous source rocks in the gippsland basin jiang and george 2018 2019 similar to the upper cretaceous rocks the aliphatic hydrocarbons in the paleogene samples are mainly comprised of n alkanes isoprenoids terpanes hopanes and steranes the aromatic hydrocarbons are dominated by naphthalene phenanthrene anthracene fluorene dibenzofuran dibenzothiophene and their alkyl homologues other aromatic hydrocarbons detected include land plant derived compounds e g retene methylretenes cadalene simonellite etc and combustion derived compounds e g chrysene pyrene picene benzo b fluoranthene benzo a anthracene etc these 4 to 6 ring polycyclic aromatic hydrocarbons are more abundant in the paleogene samples compared to the upper cretaceous rocks biomarker and aromatic hydrocarbon distributions indicate that the proteacidites asperopolus and malvacipollis diversus samples are immature or are in the early stage of the oil generation window while the lygistepollenites balmei samples correspond to the low maturity to mature stage the samples were all deposited under sub oxic to oxic conditions in fresh water with low salinity possibly in a lacustrine depositional environment the organic matter inputs are from plankton algae and higher land plants but are dominated by organic matter with a terrigenous origin

effect of sand grain size on simulated mining induced overburden failure in physical model tests abstract to investigate the influence of sand grain size sgs on mining induced overburden failure in physical model tests uniaxial compressive experiments on rock like material with various sgss were performed and two sgss 0 0 5 and 0 5 1 mm were selected the young s modulus uniaxial compressive strength and tangent modulus were larger in rock like material samples with finer sgs and the failure mode changed from mostly shear failure to tensile failure with rising sgs as the mechanical characteristics of coarser sand samples are weaker the overburden breakage distance was shorter in the coarser sand model and the ratio of the average breakage distance between the two models was 1 688 the extent of the overburden fracture was heavier in the coarser sand model and closer pattern to that of the actual coal mine a large database of the heights of the overburden caved zone hcz and fractured zone hfz values with various mining height hm based on previous studies was compiled to obtain best fit parabolic empirical formulas the hcz hm and hfz hm ratios measured in the field were similar to those estimated by the proposed empirical formulas the discrepancy between the physical model test and field measurement may be explained by the fracture pattern in the overburden of the caved zone in the form of layered rectangles unlike the polygonal forms in the coal mine we propose four recommendations to optimize the physical model for such tests from the perspective of sgs the results and recommendations presented here can provide a useful guide for coal mining scientists and engineers designing models for testing of coal mining conditions

aliphatic and aromatic terpenoid biomarkers in cretaceous and paleogene angiosperm fossils from japan abstract the distributions of aliphatic and aromatic terpenoids in cretaceous and paleogene angiosperm fossils from japan were investigated aliphatic a ring degraded oleanane ursane and lupane were found in all samples in addition aliphatic gymnosperm derived diterpenoids were detected in significant quantities aromatic oleanane type triterpenoids were the major components with ursane and lupane type triterpenoids being minor compounds in all angiosperm fossils in a cretaceous gymnosperm fossil major components included aliphatic labdane isopimarane and abietane type diterpenoids aromatic abietane type diterpenoids and chrysene and picene type polyaromatic hydrocarbons pahs trace amounts of oleanane ursane and lupane type triterpenoids were also identified it is likely that the aromatic triterpenoids were introduced to the gymnosperm fossil from the angiosperm derived material in the sediments we defined an angiosperm gymnosperm index al agi as an alternative to the aliphatic triterpenoid diterpenoid ratio proposed in the literature the al agi index may underestimate the angiosperm contribution because the aliphatic angiosperm derived triterpenoids are more readily converted to aromatic counterparts than the diterpenoids during diagenesis an aromatic angiosperm gymnosperm index ar agi can be calculated using aromatic diterpenoids and triterpenoids we suggest that ar agi is best calculated using only the oleanane ursane and lupane type aromatic triterpenoids and that the chrysene and picene type pahs be excluded

establishing relationships between structural data from close range terrestrial digital photogrammetry and measurement while drilling data abstract geologists mine planners geotechnical and mining engineers always strive for maximum information to get a better insight of the rock mass before interacting with it over the recent decades close range terrestrial digital photogrammetry crtdp has been increasingly used for data acquisition and to support the conventional methods for rock mass characterization it provides a safe time saving and contact free way to gather enough data to minimize user dependent biases however it requires an expensive camera fieldwork and some software to extract the information from images in addition it can over estimate the rock fracturing sometimes due to weathering of the rock face or poor blasting practices measurement while drilling mwd data include the responses of different drilling parameters to the variations in the rock mass mwd data are produced in large quantity as they come from every hole drilled these data correspond to the inside variations of rock rather than the surface ones counted in photogrammetry in this paper structural data are obtained from different bench faces of an open pit mine using a commercial software package shapemetrix3d by 3gsm these data are compared to the mwd data of the boreholes that were blasted to produce these bench faces to establish certain relationships between drilling parameters and rock mass structures half casts of the boreholes with mwd data were visible on the bench faces of the pre split wall that allowed a better correlation the results show abrupt changes in mwd parameters for open joints or cavities with some infilling material and overall increases or decreases in parameters for closely spaced bedding planes fractures or foliations the results are promising and suggest the method can be used to characterize the rock mass modify the charging of explosives in blasting operations and facilitate the geological modeling of the rock mass

rapid mapping and analysing rock mass discontinuities with 3d terrestrial laser scanning in the underground excavation abstract whilst laser scanning techniques have been shown to facilitate rapid identification and analysis of rock mass characteristics relatively little research has been conducted for 3d laser scanning in underground spaces in the present study a semi automatic laser scanning method has been presented for non contact discontinuity identification and rock mass characterisation in a western australian underground gold mine the accuracy of the 3d laser scanning technique was compared with traditional window mapping with a strong correlation being noted the average dip dip direction discrepancy between the two methods was found to be 1 5 16 and attributed to the ability of 3d laser scanning to collect significant quantities of data when compared to traditional methods potential sources of error together with the influence of the scale effect were discussed with an optimum scanning resolution of 7 5 mm at 5 m being noted to provide a combination of significantly reduced collection and processing time and high levels of accuracy overall the present study demonstrated the potential of 3d laser scanning techniques to replace traditional methods with increased efficiency and accuracy in underground mines

influence of asperity degradation on the mechanical behavior of rough rock joints under cyclic shear loading a cyclic shear testing system was established to investigate the mechanical behavior of rough rock joints under cyclic loading conditions laboratory cyclic shear tests were conducted for two joint types of hwangdeung granite and yeosan marble saw cut and split tensile joints prior to test the roughness of each specimen was characterized by measuring the surface topography using a laser profilometer several important aspects of cyclic joint behavior such as high peak shear strength and non linear dilation in the first loading cycle different frictional resistance for the reversed shear loading direction and anisotropic shear behavior and its dependence on the normal stress level were identified from the cyclic shear test results these features and their variations in the subsequent loading cycles are mainly due to the effect of second order asperities and strength of rock material it was also observed from experimental results that degradation of asperities under cyclic shear loading also followed the exponential degradation laws for asperity angle and the mechanism for asperity degradation would be different depending upon the shearing direction and the type of asperities based on the experimental results an elasto plastic constitutive model which can consider the degradation of second order asperities was proposed numerical simulations for the monotonic and cyclic shear loading indicated agreement with the laboratory test results

higher plant biomarkers reflect palaeovegetation changes during jurassic times abstract the relative abundances of three higher plant derived biomarkers retene cadalene and ip ihmn have been measured in marine sedimentary rocks from the northwest margin of australia it is thought that each biomarker represents input from a different plant type the distributions of these three compounds form a fingerprint representing higher plant input hpf variations in hpf in oxfordian sediments were nearly identical in all three locations with retene becoming very abundant relative to the other two compounds with decreasing age of the sediment this finding strongly suggests that the composition of terrestrial input during deposition largely determines hpf and that the possible effects of diagenesis and catagenesis on the distribution of the three biomarkers are relatively unimportant the marked increase in the abundance of retene relative to that of cadalene during the oxfordian is interpreted to reflect an increase in the contribution of plants that produced precursors for retene i e conifers brought about by a significant change in climate this was exemplified by measuring the distributions of retene and cadalene expressed in the higher plant parameter hpp for a suite of sediments from the carnarvon basin western australia covering the complete jurassic period the hpp profile displays three major cycles each covering a period of at least 10 million years this profile not only compared well with published palaeoclimate data but also showed a remarkable similarity with second order cycles in the global sea level curve thus strongly supporting the proposal that variations in hpf and hpp are indications of changes in palaeoclimate the relation with global sea level further suggests that global factors e g the atmospheric carbon dioxide concentration may play a major role in determining the observed variations in the distributions of these higher plant derived biomarkers

measurement and characterisation of spatial distributions of fractures abstract a variety of line sample 1 d and map 2 d datasets of faults and joints has been used to investigate the spatial distributions of fractures and to test techniques of fractal analysis the natural fracture datasets have been supplemented by synthetic datasets with known characteristics the fault datasets investigated range in scale from regional to outcrop and the joint datasets are derived from outcrop 1 d datasets were analysed by the spacing population interval counting and fracture number interval counting techniques 2 d datasets were analysed by box counting and fracture number box counting techniques results indicate that fracture spacing can be characterised in line samples using either the 1 d interval counting technique or more simply by measuring the spacing population as the cumulative frequency distribution of spaces between adjacent fractures tectonic faults frequently show a power law spacing population indicating fractal dimensions of between 0 4 and 1 0 but except for outcrop data truncation effects degrade the analysis unrefined joint datasets commonly show negative exponential or lognormal spacing cumulative frequency distributions however single orientation joint sets are characterised by a regular spacing and are therefore non fractal for both fault and joint map data box counting techniques do not yield the power law relationship between box size and the number of boxes that is expected of fractal geometries it is concluded that 2 d box counting techniques are too insensitive to characterise the many different parameters of a fracture array the fracture density technique appears not to discriminate between very different fracture patterns and therefore does not provide useful results a fracture pattern incorporates several attributes e g size distribution orientation linkage density roughness each of which may scale independently and each of which may be fractal with its own fractal dimension full characterisation of fracture patterns will therefore require independent analysis of each of these attributes

determination of thermal maturity and organic matter type by principal components analysis of the distributions of polycyclic aromatic compounds abstract the thermal maturity and organofacies sensitivity of polycyclic aromatic compound pac distributions was explored by examination of the aromatic fractions of solvent extracts from a diverse set of 53 shales coals and kerogen macerals which have undergone either natural or artificial maturation and which represent all three principal sedimentary organic matter om types systematic changes with maturation were observed in the following groups of isomers tri and tetramethylnaphthalenes methyl and dimethylphenanthrenes methyl and dimethyldibenzothiophenes methylpyrenes and methylchrysenes the maturity differences were quantified by mathematical ratios of the relative concentrations of the more thermally stable isomers to the less stable on the basis of theoretical considerations and empirical observations the pac maturity parameters unlike those derived from saturated biomarker stereoisomers are typically effective across the entire oil generation window to compensate for the effects of om type on the maturity parameters they were combined using principal components analysis the resulting first principal component was in good agreement with independent indicators of maturity the relative distributions of c0 c3 alkylphenanthrenes dibenzothiophene methyldibenzothiophenes and methyldibenzofurans were evaluated by a separate principal components analysis the results permitted an independent grouping of the samples by om type and suggested additional simple molecular ratios that allow graphical recognition of om type including the ratio of dibenzothiophenes to dibenzofurans and a ratio using c2 alkylphenanthrene isomers

application of aromatic compounds as maturity indicators in source rocks and crude oils concentration ratios of aromatic compounds such as naphthalenes phenanthrenes and dibenzothiophenes are at present attracting increasing attention as maturity indicators in sedimentary rocks and crude oils generally these indicators rely either on an increase with maturity in the degree of alkylation of a given parent compound or a shift in the isomer distribution of alkyl aromatic homologues towards thermally more stable isomers a combination of both concepts in the methylphenanthrene index mpi resulted in an excellent maturity parameter as demonstrated for rock extracts by an improved correlation with mean vitrinite reflectance rm between 0 65 and 1 4 i e in the zone of oil formation in cases that rm measurements were ambiguous this empirical relationship has proved useful in the calculation of theoretical vitrinite reflectance rc values from the mpi on the other hand for potential petroleum source rocks reaching maturity at relatively low temperatures the influence of the organic matter type on the aromatic distributions cannot be neglected consequently organic facies effects should be taken into account in the interpretation of aromatic distributions of such source rocks and related crude oils since the impact of the organic facies is strongly reduced with increasing maturity aromatic maturity parameters are particularly useful in the maturity evaluation of post mature crude oils and condensates in contrast to biological markers substantially higher concentrations of the key alkyl aromatics persist at elevated maturation levels thus aromatic maturity parameters should be considered as versatile tools in organic maturation studies and can complement established maturity indicators based on steranes and terpanes

biomarker signatures of upper cretaceous latrobe group petroleum source rocks gippsland basin australia distribution and geological significance of aromatic hydrocarbons abstract aromatic hydrocarbons extracted from upper cretaceous maastrichtian and campanian latrobe group coaly shales and shales from the gippsland basin were investigated by gas chromatography mass spectrometry a variety of 2 ring to 6 ring aromatic hydrocarbons were identified including both higher plant derived and combustion derived polycyclic aromatic hydrocarbons pahs these aromatic compounds indicate that the upper cretaceous coaly shales and shales were deposited in a fluvial deltaic environment with significant higher plant input and are at a relatively low thermal maturity stage higher plant parameters and angiosperm gymnosperm indices based on aromatic components suggest that higher land plants including both angiosperms and gymnosperms were an important part of the palaeovegetation in the upper cretaceous the aromatic angiosperm gymnosperm index that includes chrysene and picene type pahs is not as reliable for evaluation of relative angiosperm and gymnosperm contributions as the aliphatic indices due to input of combustion derived pahs and the complexity of burning conditions altering the relative contributions however combustion derived pahs and aromatic angiosperm gymnosperm indices supplement the information from aliphatic hydrocarbons and provide further evidence to support the hypothesis that palaeoclimate cooled from the campanian to the maastrichtian

geology mineralization alteration and structural evolution of the el teniente porphyry cu mo deposit sir the el teniente cu mo deposit in central chile is an extraordinary accumulation of cu mo ore fig 1 and we welcome the opportunity provided by skewes and stern 2007 to discuss and clarify several important issues regarding its classification and interpretation and to address several incorrect assertions that they make regarding our manuscript cannell et al 2005 we have interpreted el teniente to be a typical porphyry deposit in terms of its alteration assemblages vein and breccia styles and spatial and temporal relationships between cu mo mineralization and felsic porphyries skewes and stern 2007 dispute our claims that mineralization occurred primarily in veins and was related to felsic intrusive activity they also take issue with our interpretations of the various geochronological datasets from el teniente and our classification of el teniente as a porphyry cu mo deposit we address each of these in turn below in order to facilitate the following discussion table 1 correlates the geologic nomenclature of skewes and stern 2007 with that of cannell et al 2005 figures 1 and 2 illustrate the location of the main geologic units on underground mine level 6 at el teniente also shown on figure 1 are the approximate locations of the hypogene sulfide mineral zones figure 2 shows the block model of mo grades in the mine for more details of geologic relationships at el teniente refer to figure 4 of cannell et al 2005 and figures 4 and 5 of skewes et al 2002 although the dacite porphyry dike is shown as a single unit on figure 1 note that rojas 2002 2003 mapped multiple phases within this composite intrusive body skewes and stern 2007 criticized our use of what they assert to be an outdated map of hypogene mineralization

comparing manual and remote sensing field discontinuity collection used in kinematic stability assessment of failed rock slopes this work was supported by the university of alicante within the framework of project gre14 04 additional funding was obtained from the spanish government project number tin2014 55413 c2 2 p

detailed dem analysis of a rockslide scar to characterize the basal sliding surface of active rockslides 1 the basal sliding surfaces in large rockslides are often composed of several surfaces and possess a complex geometry the exact morphology and location in three dimensions of the sliding surface remains generally unknown in spite of extensive field and subsurface investigations such as those at the aknes rockslide western norway this knowledge is crucial for volume estimations failure mechanisms and numerical slope stability modeling this paper focuses on the geomorphologic characterization of the basal sliding surface of a postglacial rockslide scar in the vicinity of aknes this scar displays a stepped basal sliding surface formed by dip slopes of the gneiss foliation linked together by steeply dipping fractures a detailed characterization of the rockslide scar by means of high resolution digital elevation models permits statistical parameters of dip angle spacing persistence and roughness of foliation surfaces and step fractures to be obtained the characteristics are used for stochastic simulations of stepped basal sliding surfaces at the aknes rockslide these findings are compared with previous models based on geophysical investigations this study discusses the investigation of rockslide scars and rock outcrops for a better understanding of potential rockslides this work identifies possible basal sliding surface locations which is a valuable input for volume estimates design and location of monitoring instrumentation and numerical slope stability modeling

possible origin of n alkanes with a remarkable even to odd predominance in recent marine sediments abstract n alkane distributions with a remarkable even to odd predominance c16 c24 were found in marine surface sediments the previously proposed diagenetic reduction of the corresponding n fatty acids could not be considered as a source for these n alkane based on a comparison of compositional features of n alkane n fatty acid and n alcohol distributions carbon isotope analyses and other geochemical parameters the data indicate that the even predominant n alkanes were derived directly from marine bacteria

a novel series of benzohopanes widespread in sediments abstract a novel series c 31 c 35 of benzohopanes cyclized at the c 16 position has been characterized by gas chromatography mass spectrometry and nmr structural elucidation of the usually predominant c 31 member the 4 methylbenzo 16 17 21 22 29 30 trinorhop 16 ene isolated from the messel shale germany these biological markers of bacterial origin seem to be widely distributed in sediments and to show low specificity with regard to the depositional environment although they are well represented in evaporites up to now they have been detected only in thermally immature samples which could reflect either a relative fragility or other possibilities of transformation as compared to the regular benzohopanes cyclised at c 20

geochemical study on a well in the western canada basin relation of the aromatic distribution pattern to maturity of organic matter abstract thirty one rock samples from a western canada basin well have been analysed for aromatics using glass capillary gas chromatography with simultaneous flame ionization and sulfur selective flame photometric detection a uniform aromatic distribution pattern with a marked predominance of di and tricyclic aromatic hydrocarbons was observed throughout a depth interval of 3000 meters comprising cretaceous and jurassic sediments the very high relative abundance of sulfur aromatics at two narrow intervals in the triassic and mississippian is attributed to a major change in facies gradual changes with increasing depth have been observed for a series of compound ratios which had been calculated from the isomers of methyl and dimethylphenanthrene and their parent compounds these changes reflect the increasing thermal maturation of the sedimentary organic matter a methylphenanthrene index mpi has been introduced which exhibited a very good correlation with vitrinite reflectance data the mpi is the first maturity parameter which is based on a series of aromatic hydrocarbons this hydrocarbon internal maturity parameter permits the recognition and definition of maturity levels in extracts which can be compared to the maturity e g vitrinite reflectance of source rocks

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

elliptical fracture network modeling with validation in datong mine china roof coal recovery rate and the performance of gas extraction are essentially controlled by the fractures within coal rock mass thus it is important to generate the accurate fracture network ahead of mining face in this study ten boreholes located differently from the 8212 working face of tashan mine in datong coal mining group china were drilled with the help of borehole video instruments the location orientation of each fracture and the fracture number of different intersection type on each borehole wall were mapped with the advancing of mining face these data were analyzed using the matlab toolbox rjns3d and dips to determine structural homogeneity zone to find the number of fracture sets that exist in the coal rock mass volume density frequency for each set and the probability distributions of orientation fracture size in 3 d sampling biases associated with orientation spacing were corrected during the process the constructed fracture networks were validated by comparing the observed mean spacing along normal vector of mean orientation for each set and the predict value on similar scanlines

triaxial compression experiments on intact veined andesite abstract a comprehensive experimental program was instigated to test intact veined andesite from the el teniente mine chile under triaxial compression with confining pressure ranging from 2 to 60 mpa the experimental program established that the veins acted as weak mechanical components in the specimens promoting rock fracture under stress the experimental results indicated that the stress thresholds identifying the onset of dilatancy and the transition from the stable to unstable fracturing were higher in intact veined rock than in intact rock the observed behaviour illustrated a significant departure from intact rock where the onset of acoustic emissions ae correlates with the onset of specimen dilatancy the experimental results from intact veined rock indicated that the onset of ae correlated with the crack damage stress the departure from the behaviour of intact rock is attributed to the presence of veins

rock mass characterization and assessment of block forming geological discontinuities during caving of primary copper ore at the el teniente mine chile abstract the primary copper ore at the el teniente mine is very competent and massive it is a rock with almost no open discontinuities nevertheless there is a high frequency network of small scale veins coupled with widely spaced faults a research investigation was implemented to determine what discontinuities are the most relevant in the rock mass disassembly process during cave mining rock mass characterization was undertaken at four different scales within the rock mass in particular the block forming discontinuities were characterized by studying a significant number of blocks at the caving draw points two relevant discontinuity characteristics have been found the data suggest that discontinuities having approximately less than 1 3 of hard minerals as infill and thicknesses greater than or equal to 2 mm are weaker and more likely to define blocks during caving and the subsequent comminution process the infill characteristics have been used to characterize rock mass quality in different sectors and the results are in accordance with actual observations at the mine site

extraction and statistics of discontinuity orientation and trace length from typical fractured rock mass a case study of the xinchang underground research laboratory site china abstract the geological parameters of rock discontinuities are of great significance for the evaluation of high level radioactive waste repository and underground research laboratory url site characteristics to provide sufficient basis for the construction of the xinchang url site this paper presents a comprehensive set of methods for acquisition of discontinuity parameters in this set of methods a high precision three dimensional point cloud model of an outcrop with real geographic information is established based on close range photogrammetry technology from which not only planar discontinuities but also linear discontinuities can be identified and extracted by a semi automatic method a new fast fuzzy clustering method is proposed to cluster discontinuity sets the statistics method based on topographic window projection is improved to increase the rationality of estimating the geometric characteristics of fracture traces as a preliminary validation the results of this case study reveal that these methods have good applicability in acquiring discontinuity parameters which is also conducive to the establishment of a deterministic stochastic discrete fracture network dsdfn model to further analyze the properties of fractured rock mass in addition it is preliminarily found that some outcrops different locations have structures with similar geological features to a certain extent moreover the fractures exposed on the outcrop surface have distribution characteristics similar to those in the granite body obtained by drilling above all the presented multidisciplinary methods could provide an alternative and practical approach for low cost and accurate acquisition of discontinuity parameters and thus to study the properties of fractured rock mass effectively

application of synthetic rock mass modeling to veined core size samples abstract rock masses of the primary copper ore at the el teniente mine fail mainly through the infill of preexisting veins during the caving processes especially through those composed of less than 35 hard minerals quartz and pyrite in this study the synthetic rock mass srm approach is used to reproduce the results of ten uniaxial compression tests on veined core size samples of el teniente mafic complex cmet lithology from el teniente mine codelco chile at the scale of the tested samples it is observed that veins composed mostly of quartz dominate the failure process the developed methodology considers generating a deterministic discrete fracture network dfn based on the veins mapped at the surface of each core sample then the micro parameters of the bonded particle model bpm are calibrated to represent the macro parameters of the average block of intact rock within all samples next the micro parameters of the smooth joint contact model sjcm which represent the mechanical properties of veins are calibrated to reproduce the stress strain curves and the failure modes of the veined core size samples measured during the laboratory tests results show that the srm approach is able to reproduce the behavior of the veined rock samples under uniaxial loading conditions the strength and stiffness of veins as well as the vein network have an important impact on the deformability and global strength of the synthetic samples contrary to what was observed in the laboratory tests synthetic samples failed mainly through weak veins this result is expected in the modeling given that anhydrite veins are considered weaker than quartz veins further research is required to completely understand the impact of veins on the behavior of rock masses

trimethylnaphthalenes in crude oils and sediments effects of source and maturity abstract three sedimentary sequences and a number of crude oils have been analysed for trimethylnaphthalenes tmns using gas chromatography the sediments were found to contain enhanced relative abundances of 1 2 5 tmn and 1 2 7 tmn in samples of cretaceous age and younger this was especially pronounced in lower maturity sediments containing type iii organic matter older samples containing type iii organic matter were found to contain enhanced relative abundances of 1 2 5 tmn and lower relative abundances of 1 2 7 tmn 1 2 7 tmn appears to be derived directly from the structural degradation of oleanane type triterpenoids present in angiosperms and as such is proposed as a marker for this class of plant and indirectly therefore also for samples deposited since the early cretaceous the crude oils have been classified according to their trimethylnaphthalene compositions this classification enables crudes of higher plant origin to be identified and to be further classified according to whether the organic matter pre dated or post dated the evolution of angiosperms

molecular parameters of maturation in the toarcian shales paris basin france iv laboratory thermal alteration studies abstract an immature toarcian shale from the paris basin semecourt reported maximum burial depth 700m was heated in the laboratory under reduced pressure at different temperatures 201 257 285 c for different times 6 91 days we measured in the resulting extracts by gas chromatography or combined gas chromatography mass spectrometry 1 a extent of configuational isomerisation at i c 6 and c 10 in pristane ii c 20 and c 14 and c 17 in 5 h 14 h 17 h steranes iii c 17 and c 22 in hopanes 2 b extent of aromatisation in aromatic steroid hydrocarbons both configurational isomerisation and aromatisation occur during heating but the latter process is accelerated relative to the former in comparison with the maturation effect experienced by the toarcian shales as a result of burial depth and the associated temperature rise the results suggest that it may be possible to distinguish the thermal histories of sedimentary sequences by comparison of the relative extents of isomerisation at c 20 in steranes with the extent of aromatisation in aromatic steroid hydrocarbons

mechanical anisotropy of columnar jointed basalts an example from the baihetan hydropower station china abstract columnar jointed basalts are characterized by a self organized joint network of discontinuities and pose a difficult challenge for geotechnical engineering design due to their inherent anisotropic nature we explore here the anisotropic characteristics of the columnar basalt formation in the chinese baihetan hydropower station including aspects of the geometrical rock structure deformation and strength anisotropy site investigations reveal that a typical cross section of the columnar basalt blocks is mainly quadrangular and pentagonal with an average edge length of 0 152 m three types of joints with different macro and micro characteristics form the columnar jointed rock mass and are identified by scanning electron microscopy in situ ultrasonic tests further confirm that the columnar basalt prisms exhibit transverse isotropy with the plane of isotropy perpendicular to the column axis as can also be observed in the field strength anisotropy is confirmed by point load and uniaxial compression tests the mechanical and anisotropic characteristics of baihetan s jointed basalt mass can be explained by its multi scale joints pattern by means of goodman s stiffness equation we find that the anisotropic coefficients obtained for its deformability and strength are similar for all testing methods employed including in situ p wave velocity point load tests and uniaxial compression tests this result confirms the strong anisotropic effect in these rock masses and facilitates an issue that must be considered when assigning input parameters for various classification and numerical analyses schemes

semi automatic extraction of rock mass structural data from high resolution lidar point clouds abstract in this paper a matlab tool called diana discontinuity analysis for the 2d and 3d geo structural analysis of rock mass discontinuities on high resolution laser scanning data is presented the proposed approach is able to semi automatically retrieve some relevant rock mass parameters namely orientation number of sets spacing frequency and derived rqd persistence block size and scale dependent roughness by analyzing high resolution point clouds acquired from terrestrial or aerial laser scanners in addition with a specific diana option called filterveg we are able to remove vegetation or other disturbing objects from the point cloud which is one of the main problems in lidar data processing some examples of the proposed method have demonstrated its ability to investigate rock masses characterized by irregular block shapes and suggest applications in the field of engineering geology and emergency management when it is often advisable to minimize survey time in dangerous environments and in the same time it is necessary to gather all the required information as fast as possible

effects of igneous intrusions on thermal maturity of carbonaceous fluvial sediments a case study of the early cretaceous strzelecki group in west gippsland victoria australia abstract this study has investigated the effect of small igneous intrusions on early cretaceous carbonaceous fluvial sediments of the gippsland basin of south eastern australia based on outcrops in the onshore western part of the basin vitrinite reflectance measurements quantitative mineral phases and clay mineralogy were carried out on twenty two samples of organic rich mudstone up to 25 m east and west of a 1 m wide dyke samples of the dyke allowed classification as an alkali basalt based on its optical characteristics and major and trace element properties background vitrinite reflectance of 0 75 0 80 r max in the sediments is elevated up to 6 67 r max close to the dyke margin with slightly different patterns on each side of the intrusion analysis of seven selected organic rich mudstone samples shows that they all have very similar xrd patterns with the main minerals in all cases being quartz feldspar mainly plagioclase chlorite illite and interstratified illite smectite these observations suggest that the thermal maturity of the organic matter in the sediments was locally elevated by heating due to emplacement of the dyke but no significant changes were observed in host rock mineralogy that could be related to the heat generated by the dyke and the associated vitrinite reflectance variations

automatic identification and characterization of discontinuities in rock masses from 3d point clouds abstract the routine application of remote surveying techniques which can quickly acquire 3d digital data with high resolution in particular digital photogrammetry light detection and ranging lidar and unmanned aerial vehicle uav for rock mass characterization has rapidly grown over the past decade in this paper a new method for automatic identification and interpretation of rock mass discontinuities clustering of discontinuity sets and characterization of discontinuity orientation persistence and spacing using 3d point clouds is presented the proposed method is based on a four stage procedure consisting of 1 normal vector calculation using the iterative reweighted plane fitting irpf method 2 discontinuity sets clustering by fast search and find of density peaks cfsfdp algorithm and fisher s k value iterative calculation to eliminate noise points 3 discontinuity segmentation using density ratio based method and discontinuity plane fitting using the random sample consensus ransac algorithm 4 persistence and spacing calculation using the theory of analytic geometry the method is applied to two case studies i e rock slopes and compared with the results from previous studies and from manual survey it is concluded that the proposed method is reliable and yields a great accuracy for automatic identification of discontinuities in rock masses

petroleum potential and kinetic models for hydrocarbon generation from the upper cretaceous to paleogene latrobe group coals and shales in the gippsland basin australia abstract pyrolysis experiments open and closed systems and kinetic modelling of primary cracking of kerogen have been carried out to investigate hydrocarbon generation characteristics and source rock facies variability within the upper cretaceous to paleogene latrobe group in the gippsland basin on the basis of rock eval data the interbedded coals coaly shales and carbonaceous shales contain different types of kerogen type iii type ii iii type ii with variable potential for both gas and liquid hydrocarbon generation open system pyrolysis gas chromatography data indicate that the organically lean marginal marine shales of the santonian early campanian tricolporites apoxyexinus and nothofagidites senectus biozones produce gas and condensate however coal and coaly to carbonaceous shales sampled from the paleocene lygistepollenites balmei maastrichtian forcipites longus late campanian tricolporites lilliei and turonian phyllocladidites mawsonii palynological biozones are heterogeneous with the capacity to generate both low and high wax paraffinic naphthenic aromatic p n a oils and paraffinic oils with a high wax content the main phase of petroleum formation from these later biozones assuming a constant geological heating rate of 3 3 c ma is predicted to occur between 150 179 c indicating different orders of kinetic stability as a result of different types of organic matter and their state of preservation the thermally immature shales have variable bulk kinetic characteristics but the measured compositional kinetics and phase behaviour show that they have the potential to generate black oils at early stages of kerogen cracking and either light oils or wet gases at higher levels of thermal stress these findings suggest that upon thermal maturation the interbedded shales of the latrobe group may have contributed significant volumes of hydrocarbons to the oil and gas accumulations in the gippsland basin in addition this study not only supports the premise that over reliance on rock eval toc data alone can be misleading for assessment of petroleum generation but also represents a strategy for kerogen type and generative potential determination for fluvio deltaic coals and subordinate lithologies

estimating the intensity of rock discontinuities this paper presents an approach for estimating the intensity of discontinuities and formulating intensity and orientation as a fracture tensor specifically the size distribution and the number of discontinuities are estimated first from which the fracture tensor is then derived discontinuity size distribution is inferred from the trace data sampled in circular windows by using a general stereological relationship between the true trace length distribution and the discontinuity diameter distribution assuming circular shaped discontinuities because the measured trace lengths are biased a method is proposed to estimate the true trace length distribution for circular window sampling circular window sampling has the advantage of automatically eliminating the orientation bias when estimating the true trace lengths a method is then presented with which the total number of discontinuities in an objective volume can be estimated from the number of discontinuities observed in normal size boreholes and using the inferred discontinuity diameter from the circular window sampling on the rock surface with the derived size distribution and number of discontinuities the intensity of discontinuities which is the total surface area of discontinuities per unit volume can then be calculated and included in a new definition of a fracture tensor an application of the approach to analyze simulated discontinuities produces satisfactory results