tsunami of december 26 2004 on the southwest coast of india post tsunami geomorphic and sediment characteristics this paper discusses the impact of the december 26 2004 tsunami on the geomorphic features and sediment characteristics along the southwest coast of india the data used include field observations made after the tsunami and the inferences drawn from the satellite imagery taken before and after the tsunami sediment samples collected from the inner shelf beach and estuarine environments were analyzed to understand post tsunami changes in grain size characteristics the tsunami eroded and transported landwards significant volumes of distinct black sands rich in heavy minerals from the shelf onto the beaches of the kerala region and up to 500 m inland of the present coast

changes in optical properties chemistry and micropore and mesopore characteristics of bituminous coal at the contact with dikes in the illinois basin abstract changes in high volatile bituminous coal pennsylvanian near contacts with two volcanic intrusions in illinois were investigated with respect to optical properties coal chemistry and coal pore structure vitrinite reflectance ro increases from 0 62 to 5 03 within a distance of 5 5 m from the larger dike and from 0 63 to 3 71 within 3 3 m from the small dike elemental chemistry of the coal shows distinct reductions in hydrogen and nitrogen content close to the intrusions no trend was observed for total sulfur content but decreases in sulfate content towards the dikes indicate thermochemical sulfate reduction tsr contact metamorphism has a dramatic effect on coal porosity and microporosity in particular around the large dike the micropore volume after a slight initial increase progressively decreases from 0 0417 cm3 g in coal situated 4 7 m from the intrusive contact to 0 0126 cm3 g at the contact strongly decreasing mesopore and micropore volumes in the altered zone together with frequent cleat and fracture filling by calcite indicate deteriorating conditions for both coalbed gas sorption and gas transmissibility

remarkable bathymetric change in the nearshore zone by the 2004 indian ocean tsunami kirinda harbor sri lanka we investigated bathymetric data obtained at kirinda harbor sri lanka one month before and 2 and 11 months after the 2004 indian ocean tsunami our bathymetric surveyed data and numerical modeling results suggest that the first run up tsunami wave transported huge amounts of offshore sea bottom sediment and deposited it in a layer up to 4 m thick along the shoreface slope in some places this accreted sediment was not eroded by the backwash because of the particular arrangement of artificial structures and sand dunes especially the sedimentation process and the volume of the sediment transported by the run up waves can be examined where the influence of the backwash flow was very minor remarkable sedimentation attributable to the run up wave would have occurred mainly by the deposition of the sediment particles along the slope by the run up waves the slope was developed toward the stoss side rather than by the settlement of the sediment from the suspension load we estimated that considerable amounts of sediment were transported by the tsunami from the offshore sea bottom but most were deposited not on land but in the sea eleven months after the tsunami the harbor bathymetry had almost undergone complete reversion to its pre tsunami condition implying that the tsunami impact on permanent geomorphological landforms was limited at this harbor

landward fining from multiple sources in a sand sheet deposited by the 1929 grand banks tsunami newfoundland abstract a sandy deposit from the 1929 grand banks tsunami in newfoundland contains sediment from two distinct sources one from an inferred gravel shoreline close to the deposit and one from a sandy dune some 200 m seaward of the deposit the deposit ranges from 0 to 15 cm thick and is composed of a bimodal mix of fine and coarse sand we took approximately 100 core samples of this deposit in an attempt to characterize lateral grain size trends within the sand although the coarse fraction does fine with distance inland the fine fraction does not change size over the study area and the aggregate grain size changes in no systematic way we interpret this deposit to represent the mixture of material picked up at the bar with material picked up at the gravel shoreline the bar material does not fine in part because it is already fairly well sorted but also because it is far from its source the shoreline material on the other hand is poorly sorted so that the tsunami took only those grains it was capable of moving and deposited them near their source we estimated the size of the tsunami by determining the flow depth flow velocity combinations required to advect sand from the bar to the back of the deposit and by estimating the shear velocity required for motion of the largest grain we found during our survey this modeling indicates an average flow depth of about 2 5 2 8 m over the area at a flow velocity of 1 9 2 2 m s this estimate compares well with eyewitness accounts of a maximum flow depth of 7 m at the shoreline if our estimate represents an average over the whole study area

a tsunami deposit at the cretaceous tertiary boundary in texas at sites near the brazos river texas an iridium anomaly and the paleontologic cretaceous tertiary boundary directly overlie a sandstone bed in which coarse grained sandstone with large clasts of mudstone and reworked carbonate nodules grades upward to wave ripple laminated very fine grained sandstone this bed is the only sandstone bed in a sequence of uppermost cretaceous to lowermost paleocene mudstone that records about 1 million years of quiet water deposition in midshelf to outer shelf depths conditions for depositing such a sandstone layer at these depths are most consistent with the occurrence of a tsunami about 50 to 100 meters high the most likely source for such a tsunami at the cretaceous tertiary boundary is a bolidewater impact

large bedform generated by the 2011 tohoku oki tsunami at kesennuma bay japan abstract the 11 march 2011 m w 9 0 tohoku megathrust earthquake off the pacific coast of japan was a salient event in the history of japan the resultant huge tsunami the 2011 tohoku oki tsunami inundated a vast coastal area of northeastern japan causing widespread devastation twenty days after the tsunami we analyzed the impact of the tsunami on the sea bottom of the kesennuma inner bay using side scan sonar to explore the damage and bathymetric change in the harbor herein we present the first direct evidence that the sea bottom sediments of around 10 15 m were largely reworked by the tsunami to thickness of a few meters and that large dunes were formed by the tsunami considering that the sea wave influence is as weak as it is inside the inner bay the potential exists that even meter thick paleo tsunami deposits are preserved in shallow sea bottoms with large bedforms this finding will be a stepping stone to future geological studies of tsunami effects in shallow sea regions

thickness and grain size distribution of the 2004 indian ocean tsunami deposits in periya kalapuwa lagoon eastern sri lanka abstract in this paper we describe the sedimentary characteristics of the 2004 indian ocean tsunami deposits in and around periya kalapuwa lagoon sri lanka periya kalapuwa is a coastal lagoon of about 13 km 2 area and has an average depth of about 1 m it is separated from the indian ocean by coastal barrier sand dunes of up to 9 m elevation through which two inlet channels open the lagoon to the ocean this region was hit by three waves during the 2004 indian ocean tsunami the second wave was largest 4 6 m and entered the lagoon not only via the two inlet channels but also by flowing over the sand dunes erosive scars were found on the sand dunes adjacent to the two inlets twenty seven core samples along with trenching and hand auger data show that the tsunami deposits are 9 cm thick on average up to 35 cm in the lagoon and up to 66 cm on the shore and are composed mainly of medium sand mean grain size 1 06 with low mud content 0 61 wt which is similar to the composition of sand from near the erosive scars in the sand dunes mean grain size 0 94 but different from the lagoon deposits mean grain size 1 68 mud content 4 7 wt the distribution of the tsunami deposits was limited to within about 1 km from each inlet the tsunami deposits become thinner and finer grained with increasing distance from the inlets most of the tsunami deposits are massive but some show sedimentary structures single or multiple graded bedding structures parallel laminations defined by layers of heavy minerals and muddy laminations our observations and analyses suggest that the tsunami deposits were formed mainly from sand eroded from sand dunes near the two inlets we estimated the total volume of tsunami sediments to be 83 000 m 3 by assuming that the sediments of the tsunami deposits were supplied only by erosion of sand dunes from near the two inlets this is equivalent to erosion of 83 m 3 of sand per meter of sand dune traversed by the tsunami wave

a new approach to interpreting rock eval s2 and toc data for kerogen quality assessment abstract a simple method for application in source potential mapping is used to assess the original oil and gas potentials in source rock horizons based upon rock eval potential s 2 and total organic carbon toc values the method assumes that kerogens consist of mixtures of end members with assigned hydrogen index values based on suggested algorithms the average amounts of oil prone gas prone and inert organic material over source rock intervals are determined in toc units the method uses regression lines from plots of remaining hydrocarbon potentials s 2 versus total organic carbon toc and quick look transparent overlays are used to read the appropriate kerogen mixture mineral matrix effects during pyrolysis when strong can cause erroneous results this effect which occurs for oil prone kerogens and adsorptive minerals can cause problems particularly for lean samples s 2 0 3 mg hc g rock whilst the errors for richer samples are less the method is applied on three sections of upper jurassic organic rich rocks from the danish north sea sector which are at different maturity stages one of these sections is dominated by gas prone material one is dominated by oil prone material and the third section contains a mixture of oil and gas prone material the method has been compared with other methods that split kerogens in oil and gas generating potential and has given reasonable results experience using the method and a presented example suggest that sedimentological system tract information may be derived from s 2 to toc cross plots a constructed modelling example suggests that the end member concept used in this approach may be used in forward type source rock prediction models when combined with sedimentological models the resulting s 2 toc plots can be used in order to check the forward modelling results against observed values

numerical analysis of boulder transport by the 2004 indian ocean tsunami at pakarang cape thailand at pakarang cape thailand we conducted field observations and numerical modeling of the spatial and grain size distributions and sources of boulders deposited by the 2004 indian ocean tsunami the boulders are a very rare example of boulders for which a tsunami origin is well confirmed numerical modeling of the tsunami s boulder transport revealed that the grain size and spatial distributions of boulders are explainable by the initial distribution of boulders at the source and the tsunami s local behavior which is controlled strongly by the tsunami hydrodynamic features and local topography soon after the bore front reached at the beach the tsunami s hydraulic force on the tidal bench decreased suddenly below the critical force necessary to displace the boulder because of the seaward propagation of the reflected wave that had been generated at the beach slope consequently all boulders were deposited below the high tide line and subsequently concentrated at the western coast of the cape absence of boulders that had been originally deposited deeper than 10 m water depth is also explained by this reflected wave because the wave passed over boulders that had been originally deposited at 10 m water depth before the boulder crossed the reef edge our well tuned model elucidates how the tsunami was able to deposit large boulders on the tidal bench at the cape the results demonstrate that theoretically up to 250 tons of boulders might have been emplaced on the tidal bench by the 2004 indian ocean tsunami at the cape approximately 7 m wave height the calculated maximum weight is of comparable order to that of boulders around the world that are inferred to be of tsunami origin although we infer that the weight is determined based on the sensitive balance of the local topography hydrodynamic features of the tsunami and the initial distribution of boulders at the source

sediment scour and deposition within harbors in california usa caused by the march 11 2011 tohoku oki tsunami abstract tsunamis have caused significant damage to boats and docks within harbors and ports along the california coast sediment scour and deposition within harbors by tsunamis though not extensively studied have produced long term impacts to the recovery and resiliency of affected maritime communities the march 11 2011 tohoku oki teletsunami generated strong tsunami currents up to 7 m s or 14 kn within crescent city and santa cruz harbors that triggered sedimentation problems regulatory issues with sediment disposal and months of delays in the reconstruction process evaluation of video pre and post tsunami bathymetric surveys and harbor sediment analysis data helped develop a better understanding of tsunami flow regime and sediment transport within these harbors in crescent city the scour effects of large tsunami surges were amplified by the narrow entrance to the small boat basin increasing the sediment supply and trapping this material within the basin causing shoaling that made the harbor unusable and creating long term disposal issues within the entire harbor at least 289 400 m3 of sediment was scoured in an area of 0 67 km2 a minimum fill volume of 154 600 m3 was calculated with the sediment covering 55 of that portion of the harbor included in the bathymetric surveys in santa cruz the long constricting layout and shallow nature of the harbor increased current velocities and scour in confined areas and exacerbated sedimentation in between and beneath docks at the harbor entrance estimated scour volumes range from 2550 to 14 800 m3 and fill estimates range from 120 to 8750 m3 depending upon the surveys used to characterize post tsunami conditions while the area of deposition ranges from 6 to 64 of the survey overlap areas about 83 m3 of sediment was scoured in santa cruz north harbor while a minimum of 75 m3 was deposited across 50 of that portion of the harbor common to pre and post tsunami surveys fill estimates are considered minimums due to sediment deposited in locales not covered by the various surveys in general the southern part of the harbor near the entrance jetties was erosional while most of the northern part of the harbor was depositional analyses of tsunami currents observed on videos collected during the tsunami provide excellent support for the bathymetric change analyses and together the two lines of evidence provide a means to predict flow patterns and areas at risk of damage from the tsunami by assessing harbor dimensions and layout and analyzing observations video from past tsunamis reducing constrictions and deepening channels within harbors would greatly reduce tsunami current speeds and the potential for scour the maritime community and state regulatory agencies should work together to streamline the review process to assist recovery efforts after significant tsunamis

spatial thickness variability of the 2011 tohoku oki tsunami deposits along the coastline of sendai bay abstract soon after the 2011 tohoku oki event approximately 1300 tsunami deposit thickness data were collected spatially by the governors to cover the entire tsunami affected area sendai plain along the sendai bay coastline this dataset along with high resolution and high precision data of flow depth and pre tsunami and post tsunami elevation enables us first to conduct a direct comparison of the sedimentation and erosion volumes as well as the tsunami hydrodynamic features e g flow depth and sediment thickness the total balance of sedimentation and erosion volumes revealed that the volume of tsunami deposited sediments can be explained roughly using the erosion volumes at the beach and sand dunes for sandy deposits and at rice paddy fields for muddy deposits both the flow depth and sediment thickness showed positive correlations with the distance from the shoreline while sediment thickness is no correlation to the elevation except in the zone closest to the shoreline where erosion is present in addition a statistical relation was found between the flow depth and sediment thickness in fact the frequency distribution of sediment concentration defined here as the sediment thickness divided by the maximum flow depth at each survey site fits well with the logarithmic normal distribution with geometric average of about 2 this fit indicates that the tsunami deposits on the sendai plain can be explained generally if we simply assume that the saturated level of the sediment concentration in the flow is limited to about 2 on average irrespective of the grain size such a simple explanation might be applicable only for the tsunami deposits on the sendai plain because the topography is remarkably flat and low therefore the tsunami inundation process is relatively simple nevertheless a possible relation between tsunami flow depth and sediment thickness suggested here would be very useful to consider the ideal sedimentary process of the tsunami deposits and to improve forward and inverse modelings

tide gauge observations of the indian ocean tsunami december 26 2004 the magnitude 9 0 earthquake centered off the west coast of northern sumatra 3 307 n 95 947 e on december 26 2004 at 00 59 utc united states geological survey usgs 2005 usgs earthquake hazards program latest earthquakes earthquake hazards program http earthquake usgs gov eqinthenews 2004 usslav 2005 generated a series of tsunami waves that devastated coastal areas throughout the indian ocean tide gauges operated on behalf of national and international organizations recorded the wave form at a number of island and continental locations this report summarizes the tide gauge observations of the tsunami in the indian ocean available as of january 2005 and provides a recommendation for the use of the basin wide tide gauge network for future warnings

characteristics of type iii kerogen in coal bearing strata from the pennsylvanian upper carboniferous in the ruhr basin western germany comparison of coals dispersed organic matter kerogen concentrates and coal mineral mixtures abstract quality quantity and maturity of coal and dispersed terrigenous organic matter were studied on six coal bearing intervals in duckmantian strata pennsylvanian upper carboniferous of the ruhr basin western germany between 10 and 40 samples were collected from fresh drill cores of each interval typically consisting of a coal seam as well as clastic roof and floor strata sandstone siltstone claystone coal seams constitute about 8 vol of the succession studied the samples were analysed by organic petrological methods and rock eval pyrolysis maturity expressed in terms of vitrinite reflectance is between 0 75 and 1 0 for the six successions studied the total amount of dispersed organic matter in clastic rocks is about half of that stored in coal seams both containing predominantly vitrinite significant differences between rock eval parameters determined on whole rock samples and kerogen concentrates were observed especially with respect to hydrogen index hi values thus the hi of the coal is about twice as high as that of the dispersed organic matter although the maceral composition is similar the effects of minerals were further examined by rock eval pyrolysis of artificial mixtures of coal lignite powder and different minerals reduced hi values are partly explained by the retention of generated hydrocarbons on mineral surfaces and partly by reactions of generated fluids with pyrite in kerogen concentrates

change in the magnetic properties of bituminous coal intruded by an igneous dike dutch creek mine pitkin county colorado abstract magnetization measurements have been made on natural coke coal samples collected at various distances from a felsic porphyry dike in a coal seam in dutch creek mine colorado to help characterize the nature and distribution of the iron bearing phases the magnetization passes through a maximum at the coke to coal transition about 31 cm from the dike contact the magnetic measurements support the geochemical data indicating that magmatic fluids along with a high temperature gas pulse moved into the coal bed interaction of the magmatic fluids with the coal diminished the reducing power of the thermal gas pulse from the dike to a point about 24 cm into the coal the hot reducing gas penetrated further and produced a high temperature 400 525 c zone at about 31 cm just ahead of the magmatic fluids metallic iron found in this zone is the principal cause of the observed high magnetization beyond this zone the temperature was too low to alter the coal significantly

influence of petrographical composition on coking behavior of inertinite rich coals abstract medium rank inertinite rich coal samples were collected for study from limnic and paralic facies in the upper silesian coal basin of poland the microlithotypes seem to control the content of the mosaic textures it also appears that carbominerites favor the formation of pyrolytic carbons the coke obtained from poorly pyrofusinitized homogeneous limnic coal has higher mechanical strength with larger and thicker cell walls and is less porous than those derived from highly pyrofusinitized heterogenous paralic ones the microstructure of the cokes appears to be controlled by different amounts of fibers and coarse mosaics

numerical assessment of bathymetric changes caused by the 2004 indian ocean tsunami at kirinda fishery harbor sri lanka abstract thus far various numerical models have been developed and improved to aid understanding of the sediment transport process due to tsunamis however the applicability of these models for the field scale bathymetric change remains a major issue due to the scarcity of measured bathymetric data immediately before and after tsunamis this study focuses on assessing the applicability of the sediment transport model by comparing the model results with measured bathymetry data obtained one month before and two months after the 2004 indian ocean tsunami at kirinda fishery harbor sri lanka obtained model results were compared with measured data along four different transects in particular similar to the measured data the model reproduced the bed level change at the harbor mouth well although it shows some discrepancy on bathymetric change along the shoreline which is directly affected by littoral drift therefore it is noted that the divergence of reproducing the local bathymetry change is due to the normal wind wave effect on measured data and the model limitations hence we included the wind wave effect in modeled data and the discrepancy between measured and modeled data was reduced furthermore the modeled bed level change indicates a dynamic behavior in terms of the net variation during the tsunami flow such that deposition dominates in the inflow and erosion dominates in the backflow both bed level variation and the suspended load concentration reveal that the large amount of eroded sediment attributable to tsunami waves was in suspended form and was deposited in the nearshore area after the water fluctuation had abated the model results further indicate that eroded sediment at the initial depth deeper than 11 m might be brought by the incoming tsunami waves and deposited in the nearshore area where the depth is shallower than 7 m

horizontal and vertical variation of 2004 indian tsunami deposits an example of two transects along the western coast of thailand abstract we investigated horizontal and vertical variations in modern tsunami deposits along two transects at nam khem and khao lak western coast of thailand deposited by the large tsunami associated with the earthquake magnitude 9 0 of 26 december 2004 off sumatra indonesia tsunami waves 6 10 m high struck the area approximately 2 h after the earthquake tsunami deposits cover the low lying coastal plains and extend more than 1 km inland from the shoreline no landward decrease in sediment thicknesses was found clearly at either transect terrace scarps and a steep slope behind the coastal plain probably stopped tsunami deposition further inland causing substantial sediments to be deposited in front of these features very clear vertical variations in grain size and multiple layers are found in the deposits to about 600 m inland at nam khem fine grained sediments overlie the coarse grained sediments of the basal layer of the tsunami deposits at some sites the fine grained sediments are overlain by another layer of coarse grained sediments suggesting deposits laid down in succession by multiple waves the basal coarse grained sediments at nam khem fine landward the up flow waned inland based on the assumption that the grain size of the basal deposits relates to the strength of the up flow these results are potentially useful in disaster prevention and coastal environmental change management as well as for interpreting paleotsunami deposits in geological records

tsunami deposits beneath tidal marshes on northwestern vancouver island british columbia two sand sheets underlying tidal marshes at fair harbour neroutsos inlet and koprino harbour on the northwestern coast of vancouver island british columbia were probably deposited by tsunamis the sand sheets become thinner and finer grained landward drape former land surfaces contain marine microfossils are locally graded or internally stratified and can be correlated with earthquakes that generated tsunamis in the region 137cs dating and historical accounts indicate that the upper sand sheet was deposited by the tsunami from the great alaska earthquake in 1964 radiocarbon ages on plant fossils within and on top of the lower sand sheet show that it was deposited sometime after about a d 1660 we attribute the lower sand sheet to a tsunami from the most recent plate boundary earthquake on the cascadia subduction zone about 300 yr ago extending the documented effects of this earthquake north of the nootka fault zone the 1964 tsunami deposits differ little in thickness and continuity among the three marshes in contrast the lower sand sheet becomes thinner and less continuous to the north implying a tsunami source south of the study area

geochemical truths in large data sets i geochemical screening data abstract organic geochemistry especially when undertaken on a well by well or outcrop by outcrop basis arguably lacks statistically significant numbers of analyses to establish reliable trends can a reliable vitrinite reflectance vs depth trend be established from say 12 analysed samples when the number of analysed samples are in the hundreds or even thousands much clearer general trends are established and anomalous measurements more readily recognised interpretation of anomalies is itself highly instructive but forms another paper in this paper a global data set of some 5000 source rock samples is assembled from the open literature and released data e g open file reports and the results discussed to produce practical oil industry interpretations from basic screening data a complex conclusion can be extracted from simple data sets and are supported by mass balance and kinetic theory it is concluded that interpretation always falls back on a comparison of new data with pre existing knowledge in the form of tables and plots total organic carbon toc values are generally log normally distributed so that using mean standard deviation values will under estimate the upside potential when fed into risked probabilistic hydrocarbon charge prediction models kerogen type is initially best determined using plots of rock eval s 2 vs toc rather than the hydrogen index hi s 2 toc vs oxygen index oi s 3 toc or pseudo van krevelen plot the intercept of the s 2 vs toc plot predicts the average dead carbon inertinite content of the source rock set with the slope corresponding to the hydrogen index of the labile component hi l maturity trends of the hydrogen index vs t max or r o show reversals at high maturities as supported by the kinetics of the thermal breakdown of the three standard kerogen types at elevated maturities type iii kerogens have higher hydrogen indices than types i and ii kerogens a feature that must be taken into account when correcting mature kerogens to their original hi values hi o the reduction in hydrogen index is a measure of generation with the corresponding increase in production index pi s 1 s 1 s 2 being effectively a measure of hydrocarbon retention a cross plot of hi vs pi can be interpreted in terms of expulsion efficiencies expelled generated minus retained hydrocarbon measured data support a pore saturation and or generation pressure driven process for expulsion and indicate a limiting pore saturation equivalent to a production index of 0 6 for rich 2 toc source rocks

hydrodynamic implications of textural trends in sand deposits of the 2004 tsunami in sri lanka abstract field observations and sediment samples at a coastal plain setting in southeastern sri lanka were used to document the erosional and depositional impacts of the 2004 indian ocean tsunami and to interpret the hydrodynamic processes that produced an extensive sand sheet deposit tsunami deposit thicknesses ranged from 6 to 22 cm with thickness being controlled partly by antecedent topography the deposit was composed of coarse to medium sand organized into plane parallel laminae and a few laminasets vertical textural trends showed an overall but non systematic upward fining and upward thinning of depositional units with an upward increase in heavy mineral laminations at some locations repeated patterns in the vertical textural trends upward fining upward coarsening uniform were used to subdivide and correlate the deposit into five hydro textural stratigraphic units the depositional units were linked to hydrodynamic processes and upcurrent conditions such as rates of sediment supply and composition of the sediment sources vertical changes in grain size distributions recorded the depositional phases associated with flow acceleration initial unsteady pulsating flow relatively stable and uniform flow flow deceleration slack water and return flow or flow redirection study results suggest that vertical textural trends from multiple cross shore sections can be used to interpret complex tsunami flow histories but at the location examined interpretation of the lateral textural trends did not provide a basis for identifying the correct sediment transport pathways because flow near the landward boundary was multidirectional

thermal maturity source rock potential and kinetics of hydrocarbon generation in permian shales from the damodar valley basin eastern india abstract this study investigates the source rock characteristics of permian shales from the jharia sub basin of damodar valley in eastern india borehole shales from the raniganj barren measure and barakar formations were subjected to bulk and quantitative pyrolysis carbon isotope measurements mineral identification and organic petrography the results obtained were used to predict the abundance source and maturity of kerogen along with kinetic parameters for its thermal breakdown into simpler hydrocarbons the shales are characterized by a high toc 3 4 mature to post mature heterogeneous type ii iii kerogen raniganj and barren measure shales are in mature late oil generation stage rr raniganj 0 99 1 22 rr barren measure 1 1 1 41 vitrinite is the dominant maceral in these shales barakar shows a post mature kerogen in gas generation stage rr barakar 1 11 2 0 and consist mainly of inertinite and vitrinite the 13corg value of kerogen concentrate from barren measure shale indicates a lacustrine marine origin 24 6 30 84 vs vpdb and that of raniganj and barakar 22 72 25 03 vs vpdb show the organic provenance to be continental the 13c ratio of thermo labile hydrocarbons c1 c3 in barren measure suggests a thermogenic source discrete bulk kinetic parameters indicate that raniganj has lower activation energies e 42 62 kcal mol compared to barren measure and barakar e 44 68 kcal mol temperature for onset 10 middle 50 and end 90 of kerogen transformation is least for raniganj followed by barren measure and barakar mineral content is dominated by quartz 42 63 siderite 9 15 and clay 14 29 permian shales in particular the barren measure as inferred from the results of our study demonstrate excellent properties of a potential shale gas system

sedimentological and geomorphological imprints of holocene tsunamis in southwestern spain an approach to establish the recurrence period this paper reviews the sedimentological and geomorphological imprints of prehistoric and historical tsunamis in the four main estuaries of sw spain these imprints include beach erosion filling of intertidal channels deposition of bioclastic layers washover fans and reworked aeolian sheets and the breaching of spits and tombolos most of these imprints were caused by the 218 209 bc and ad 1755 tsunamis although evidence of other tsunamis has been identified in these two events effects on human populations were severe and diverse such as human loss of life changes in coastal settlements and international borders damage to port infrastructure or flooding of marsh and inhabited areas new radiocarbon reservoir data were included in order to obtain an approach to the recurrence period of these high energy events 700 1000 years in this area 2013 elsevier b v

evaluation of source rock potential matrix effect and applicability of gas oil ratio potential factor in paleocene eocene bituminous shales of camalan formation nallihan turkey abstract in order to improve the reliability and accuracy of source rock evaluation a total of 102 shale samples of camalan formation were collected analyzed and re characterized with taking matrix retention effect into account results from rock eval and visual kerogen analyses indicate 1 an excellent source rock with an average toc of 6 39 wt 2 an assemblage of amorphous i e alginite type i organic matter as a major organic constituent with an excellent potential for generating oil 3 shale samples from camalan formation are in immature early intermediate stage of maturity based on tmax avg 440 c and spore color index sci 2 5 4 also no amount of camalan generated oils are migrated out of shale based on s1 vs toc plot i e transformation ratio tr 0 samples of this study show a significant mineral matrix effect after correction of mineral matrix effect the average hydrogen index hi of the camalan formation increased by more than 60 mg hc g toc and reached to an average of 811 mg hc g toc gas oil ratio potential gorp factor were used in order to split up the toc and s2 into oil prone and gas prone and also to investigate the level of consistency between the results of gorp factor and those of visual kerogen studies based on obtained gorp factor more than 90 of toc live is composed from oil prone materials which is in acceptable agreement with petrographic assessments

beach recovery after 2004 indian ocean tsunami from phang nga thailand the 2004 indian ocean tsunami devastated the coastal areas along the andaman western coast of thailand and left unique physical evidence of its impact including the erosional landforms of the pre tsunami topography here we show the results from monitoring the natural recovery of beach areas at khuk khak and bang niang tidal channels of khao lak area phang nga thailand a series of satellite images before and after the tsunami event was employed for calculating the beach area and locating the position of the changed shoreline field surveys to follow up the development of the post tsunami beach area were conducted from 2005 to 2007 and the yearly beach profile was measured in 2006 as a result the scoured beach areas where the tidal channel inlets were located underwent continuous recovery the return of post tsunami sediments within the beach zone was either achieved by normal wind and wave processes or during the storm surges in the rainy season post 2004 beach sediments were derived mainly from near offshore sources the present situation of the beach zone has almost completed reversion back to the equilibrium stage and this has occurred within 2 years after the tsunami event we suggest these results provide a better understanding of the geomorphological process involved in beach recovery after severe erosion such as by tsunami events

sediments deposited by the 2004 indian ocean tsunami along the malaysia thailand peninsula stratigraphy grain size distribution and foraminiferal assemblages of pre tsunami and tsunami sediment from the indian ocean tsunami at five sites along the malaysia thailand peninsula were analyzed to gain information on tsunami sediment source and deposition style between three and five stratigraphic units were identified at each site and contained between one and three fining upward sequences reflecting waning flow or pre backwash deposition coarser sand layers reflecting uprush high energy flow separated the fining upward sequences with the exception of one site sungai burong which contained a coarsening upward sequence all contacts between the pre tsunami and tsunami sediment were sharp or erosional medium and coarse sand dominated all of the tsunami sediment deposits and often contained shell fragments foraminiferal assemblages were able to differentiate pre tsunami sediment from tsunami sediment where no lithological or grain size distribution change was evident between two and four foraminiferal zones were identified at each of the five sites and provided estimates of sediment source and wave characteristics

organic geochemistry of dsdp site 467 offshore california middle miocene to lower pliocene strata abstract results of the analyses of twenty three samples from the middle miocene to lower pliocene strata from dsdp site 467 offshore california are presented the analyses were performed with the aim of determining the origin of the organic matter the stratigraphic section s hydrocarbon generation potential and extent of organic diagenesis organic carbon contents are an order of magnitude greater than those typically found in deep sea sediments suggesting an anoxic depositional environment and elevated levels of primary productivity hydrocarbon generation potentials are above average for most samples the results of elemental analyses indicate that the kerogens are primarily composed of type ii organic matter and are thermally immature analysis of the bitumen fractions confirms that the samples are immature in cores from 541 to 614 meters the gas chromatograms of the c 15 non aromatic hydrocarbon fractions are dominated by a single peak which was identified as 17 h 18 h 21 h 28 30 bisnorhopane this interval is the same area in which the highest degrees of anoxia are observed as reflected by the lowest pristane phytane ratios this correlation may have some implications with regard to the origin of the bisnorhopane and its possible use as an indicator of anoxic depositional conditions within thermally immature sediments

estuarine morphology recovery after the 2011 great east japan earthquake tsunami abstract the 2011 great east japan tsunami caused severe morphological changes along the affected coastline on the northeast part of japan this study investigates the recovery of river mouths and breaching of sandy coast at the place used to be river mouth in miyagi prefecture japan after severe erosion induced by the tsunami through analyzing aerial photograph and investigating field data after several years since the tsunami took place the morphology of some river mouths has mostly recovered while others still have some damage results on the analysis of aerial photograph clearly indicate that the total length of sandy coast on both sides of river mouth plays important role in the recovery process moreover the relevant phenomenon occurring during the morphological recovery process is also investigated the findings demonstrated the intrusion of sand spit into river mouths due to the tsunami having scoured river mouth deeper than the depth of closure interestingly the intrusion distance was found to be positively correlated with the width of river mouth in addition there is an important finding on the practical problem which is related to the intrusion upstream of sand spit that intrusion shifts the boundary of fresh sea water upstream therefore external wave forces must be considered when implementing the design of river structures

direct evidence for organic carbon preservation as clay organic nanocomposites in a devonian black shale from deposition to diagenesis abstract the burial of marine sourced organic carbon oc in continental margin sediments is most commonly linked to oceanographic regulation of bottom water oxygenation anoxia and or biological productivity here we show an additional influence in the devonian woodford shale in which oc occurs as nanometer intercalations with specific phyllosilicate minerals mixed layer illite smectite that we term organo mineral nanocomposites high resolution transmission electron microscopic hrtem images provide direct evidence of this nano scale relationship while discrete micron scale organic particles such as tasmanites algal cysts are present in some lamina a strong relation between total organic carbon toc and mineral surface area msa over a range of 15 toc indicate that the dominant association of organic carbon is with mineral surfaces and not as discrete pelagic grains consistent with hrtem images of nanocomposites where periods of oxygenation are indicated by bioturbation this relationship is modified by a shift to lower oc loading on mineral surfaces and reduced msa variability likely resulting from biological mixing and homogenization of the sediment oxidative burn down of oc and or stripping of oc from minerals in animal guts the toc msa relationship extends across a range of burial depths and thermal maturities into the oil window and persists through partial illitization where illitization occurs the loss of mineral surface area associated with the collapse of smectite interlayer space results in a systematic increase in toc msa and reorganization of organic carbon and clays into nano scale aggregates while the woodford shale is representative of black shale deposits commonly thought to record heightened marine productivity and or anoxia our results point to the importance of high surface area clay minerals for oc enrichment given that the vast majority of these clay minerals are formed in soils before being transported to continental margin settings their mineralogy and attendant preservative potential is primarily a function of continental climate and provenance making these deposits a sensitive recorder of land as well as oceanographic change

palynomorph optical analyses for thermal maturity assessment of upper ordovician katian hirnantian rocks from southern estonia abstract application of integrated multi proxy optical analytical techniques for the assessment of thermal maturity of organic matter was tested in katian to hirnantian upper ordovician sediments from a subsurface succession in southern estonia the investigated valga 10 drill core section consists of a biostratigraphically well constrained succession deposited in the outer part of a carbonate shelf livonian basin the diverse and well preserved palynological assemblages permitted the analysis of thermally induced modifications of optical properties of small and large acanthomorph acritarchs qualitative methods such as uv fluorescence and acritarch alteration index aai were calibrated against the quantitative palynomorph darkness index pdi the occurrence of vitrinite like organoclasts allowed reflectance measurements in some of the investigated samples the strong fluorescence and pale to yellow colour of acritarchs combined with low pdi and organoclast reflectance values suggest thermally immature kerogen and a limited burial diagenesis in the study area moreover pdi showed a good correlation with uv fluorescence allowing a calibration of these two techniques and proving the reliability of pdi for thermal maturity estimation in sedimentary rocks unsuitable for rock eval pyrolysis and vitrinite reflectance furthermore the applied methodologies permitted the differentiation of reworked from in situ organic matter and highlighted the potential of the former for sequence stratigraphic investigations

tsunami induced conglomerates in miocene upper bathyal deposits chita peninsula central japan abstract the tsubutegaura conglomeratic tsunamiites occur in the middle section of the miocene storm related sand silt alternation system in the chita peninsula central japan deposition of the system in the upper bathyal environment in a bay and synsedimentary seismic activity has been elucidated by palaeontological palaeogeographical and sedimentological studies two coupled units each built up by a conglomerate layer with an overlying sandstone layer and the alignment of lenticular sedimentary bodies are exceptional in this sequence some typical lenticular bodies confined within sedimentary troughs consist of a boulder bearing conglomerate layer and calcareous sandstone layer of the lower couple and another conglomerate layer of the upper couple the tuffaceous sandstone layer of the upper couple is distributed more widely than the other lithologies the framework gravels in the coupled conglomerates form a clast supported fabric and are quite notably monomictic the clasts are angular and imbricated partly forming peculiar gravel clusters due to traction current transportation conspicuous laminations develop in the coupled sandstone layers antidunes with chute and pool structure in the upper couple sandstone layer indicate deposition from an upper flow regime current on the other hand the calcareous composition of the lower couple sandstone layer reveals shallow water provenance thixotropic deformations and diastasis cracks in the siltstone bed immediately beneath the layers of the couples show that a severe earthquake tremor and a rapid change of water pressure occurred just before the deposition of the tsunamiites submarine debris flows due to collapse of a fault scarp in a shallow bank and the ensuing wash by two pulses of the tsunami induced ebb current comprise the scenario for the formation of the tsubutegaura conglomeratic tsunamiites

distribution origin and transport process of boulders deposited by the 2004 indian ocean tsunami at pakarang cape thailand abstract the tsunami of 2004 in the indian ocean transported thousands of meters long boulders shoreward at pakarang cape thailand we investigated size position and long axis orientation of 467 boulders at the cape most of boulders found at the cape are well rounded ellipsoid in shape without sharp broken edges they were fragments of reef rocks and their sizes were estimated to be 3 22 7t the distribution pattern and orientation of long axis of boulders reflect the inundation pattern and behavior of the tsunami waves it was found that there is no clear evidence indicating monotonous fine coarse shoreward trends of these boulders along each transect line on the other hand the large boulders were deposited repeatedly along the three arcuate lines at the intertidal zone with a spacing of approximately 136m interval this distribution pattern may suggest that long lasting oscillatory flows might have repositioned the boulders and separated the big ones from small no boulders were found on land indicating that the hydraulic force of the tsunami wave rapidly dissipated on reaching the land due to the higher bottom friction and the presence of a steep slope we further conducted numerical calculation of tsunami inundation at pakarang cape according to the calculation the sea receded and the major part of the tidal bench area with boulders at present was exposed above the sea surface before the arrival of the first tsunami wave the first tsunami wave arrived at the cape from west to east at approximately 130min after the tsunami generation and then inundated inlands our calculation shows that tsunami wave was focused around the offshore by a small cove at the reef edge and spread afterwards in a fan like shape on the tidal bench the critical wave velocities necessary to move the largest and average size boulders by sliding can be estimated to be approximately 3 2 and 2 0m s respectively the numerical result indicates that the maximum current velocity of the first tsunami wave was estimated to be from 8 to 15m s between the reef edge and approximately 500m further offshore this range is large enough for moving even the largest boulder shoreward these suggest that the tsunami waves that were directed eastward struck the reef rocks and coral colonies originally located on the shallow sea bottom near the reef edge and detached and transported the boulders shoreward

flow conditions of the 2004 indian ocean tsunami in thailand inferred from capping bedforms and sedimentary structures the 2004 indian ocean tsunami deposited a sheet of sand with surficial bedforms at the andaman coast of thailand here we show the recognition of bedforms and the key internal sedimentary structures as criteria of the tsunami supercritical flow condition the presence of well preserved capping bedforms implied a dominant tsunami inflow sets of internal sedimentary structures including parallel lamination seaward and landward inclined laminations and downstream dipping laminae indicated antidune structures that were generated by a supercritical flow current in a depositional stage during the inflow a set of seaward dipping cross laminations containing sand with mud drape on the surface of one depositional layer are a unique indication of an outflow structure a majority of deposits show normal grading but in some areas localized reverse grading was also observed the recognition of these capping bedforms and determination of the internal sedimentary structures provides new key criteria to help derive a better understanding of tsunami flow conditions

estimation of the nearshore bathymetry from high temporal resolution sentinel 1a c band sar data a case study abstract the study of the changes in swell properties in the nearshore domain due to interaction with the sea bottom to infer the bathymetry has deserved some attention in the last few years satellite remote sensing images in particular synthetic aperture radar sar have been used to produce a directional wave spectrum by fast fourier transform fft from which the wavelength and wave direction of the ocean surface waves can be retrieved these wave properties can be directly used in the linear dispersion relation to estimate the water depth the present work takes advantages from the very short revisit times of the sentinel 1a with c band 5 405 ghz sar images with 10 m of spatial resolution to study the repeatability of this methodology for deriving the nearshore sea bottom morphology using a case study in the aveiro region located in the portuguese west coast this site is exposed to high energetic wave climate of the north atlantic ocean overall a set of four images were selected for the analysis the robustness of the fft methodology to calculate the wavelength and wave direction from sar images was analysed through calculating their standard deviations the errors of estimating the local bathymetry from these quantities was accessed which allowed to quantify the water depth limits of application of this methodology the set of images was used to establish a bathymetric estimation that merges the derived bathymetry of each image the computed bathymetry was quantitatively compared with the measurements made in 2013 and available at raia observatory the relative error of the water depth ranges between 6 and 10 but increases for the higher depths and depends on the accuracy of the computed wavelength at deep waters the merged derived bathymetry also provides a better approximation for the measured bathymetry than those derived from the individual images

beach profile change at hasaki japan caused by 5 m high tsunami due to the 2011 off the pacific coast of tohoku earthquake abstract the beach profile change caused by the 5 m high tsunami striking the sandy hasaki coast of japan in 2011 was investigated using numerical simulation results and a detailed field data set including the beach profiles measured just 6 h before and three days after the tsunami attack the magnitude of the tsunami induced profile change had roughly the same relation to the wave energy flux as did the profile changes caused by wind generated waves at this location however the mechanisms underlying the morphological changes were different the beach profile changes due to wind waves were induced by smaller bottom stresses with longer duration whereas the profile change due to the tsunami was induced by larger bottom stresses with shorter duration simulation results showed that the tsunami induced beach profile change including the offshore bar erosion was largely caused by suspended sediments transported by the uprush flows of the first two tsunami waves compared with the amount of beach profile change at banda aceh due to the 2004 indian ocean tsunami that at hasaki due to the 2011 tsunami was small the main reason for this is likely the difference in tsunami height 5 m at hasaki and 10 m at banda aceh the second cause may be the topography of the land

barrier spit recovery following the 2004 indian ocean tsunami at pakarang cape southwest thailand abstract the 2004 indian ocean tsunami had notable impacts on coastal landforms temporal change in topography by coastal erosion and subsequent formation of a new barrier spit on the nearshore of pakrang cape southeastern thailand had been monitored for 10 years since 2005 based on field measurement using satellite images high resolution differential gps and or handy gps monitored topography data show that a barrier island was formed offshore from the cape several months after the tsunami event through progradation of multiple elongated gravelly beach ridges and washover fan composed of coral gravels subsequently the barrier spit expanded to the open sea the progradation and expansion were supported by supply of a large amount of coral debris produced by the tsunami waves these observations provide useful data to elucidate processes of change in coastal landforms after a tsunami event the 2004 indian ocean tsunami played an important role in barrier spit evolution over a period of at least a decade

field measurements and numerical simulations of the 2004 tsunami impact on the east coast of sri lanka this paper employs a numerical model of tsunami propagation together with documented observations and field measurements of the evidence left behind by the tsunami in december 2004 to identify and interpret the factors that have contributed to the significant spatial variability of the level of tsunami impact along the coastal belt of the eastern province of sri lanka the model results considered in the present analysis include the distribution of the amplitude of the tsunami and the pattern of wave propagation over the continental shelf off the east coast while the field data examined comprise the maximum water levels measured at or near the shoreline the horizontal inundation distances and the number of housing and other buildings damaged the computed maximum amplitude of the tsunami at water points nearest the shoreline along the east coast shows considerable variation ranging from 2 2 m to 11 4 m with a mean value of 5 7 m moreover the computed amplitudes agree well with the available field measurements we also show that the shelf bathymetry off the east coast particularly the submarine canyons at several locations significantly influences the near shore transformation of tsunami waves and consequently the spatial variation of the maximum water levels along the coastline the measured values of inundation also show significant variation along the east coast and range from 70 m to 4560 m with a median value of 700 m our analyses of field data also show the dominant influence of the coastal topography and geomorphology on the extent of tsunami inundation furthermore the measured inundation distances indicate no apparent correlation with the computed tsunami heights at the respective locations we also show that both the computed tsunami heights and the measured inundation distances for the east coast closely follow the log normal statistical distribution

diatom assemblages in tsunami deposits associated with the 2004 indian ocean tsunami at phra thong island thailand abstract diatom assemblages in sandy deposits of the 2004 tsunami at phra thong island thailand may provide clues to flow conditions during the tsunami the tsunami deposits contain one or more beds that fine upward commonly from medium sand to silty very fine sand diatom assemblages of the lowermost portion of the deposit predominantly comprise unbroken beach and subtidal species that live attached to sand grains the dominant taxa shift to marine plankton species in the middle of the bed and to a mix of freshwater brackish and marine species near the top these trends are consistent with expected changes in current velocities of tsunami through time during high current velocities medium sand is deposited only beach and subtidal benthic diatoms attached to sediment can be incorporated into the tsunami deposit high shear velocity keeps finer material including planktonic diatoms in suspension with decreasing current velocities finer material including marine plankton can be deposited finally during the lull between tsunami waves the entrained freshwater brackish and marine species settle out with mud and plant trash low numbers of broken diatoms in the lower medium sand implies rapid entrainment and deposition whilst selective breakage of marine plankton thalassionema nitzschioides and thalassiosira and coscinodiscus spp in the middle portion of the deposit probably results from abrasion in the turbulent current before deposition

possible tsunami inundation identified amongst 4 5th century bce archaeological deposits at tel ashkelon israel abstract the eroding coastal sections of ashkelon israel contain exposed sequences of natural and anthropogenic sedimentological deposits some of unknown origin ashkelon an important and long occupied ancient coastal city is directly referred to within written records of past tsunami events yet field studies and archaeological descriptions have not yet corroborated these claims this is not unusual nor unexpected given the amount of anthropogenic and natural disturbance that can erase the sedimentary remains as well as the relatively recent advancements in identifying such deposits a sequence of sediments at the base of an eroding coastal archaeological section shows clear waterborne transport characteristics and was previously interpreted as alluvial however no alluvial sources could be associated to the deposit in this study the sedimentological characteristics of this section were described and analyzed in greater detail to determine their nearest similarity to possible transport mechanism such as storms rivers and tsunamis the deposits contain fining upward sequences rip up clasts imbricated inclusions fine mud layers microfauna foraminifera and broken diagnostic pottery from the 4 5th c bc reconstructions of the coastline at the time of the event place the sampled profile at least 100 m inland from the shoreline at an elevation 2 0 to 2 4 m above sea level river channel features were not identified in the section for this area modern observations of major storms show inundations of

inflow and outflow facies from the 1993 tsunami in southwest hokkaido abstract we describe in detail the sedimentary facies provenance and grain size distributions of the 1993 tsunami deposits in the lower reaches of usubetsu river only two lithofacies were recognized a gravel lobe facies glf and a sand sheet facies ssf the gravel lobe facies was deposited rapidly by a hydraulic jump in contrast the sand sheet facies which contains both current ripples and dunes was deposited by a traction current under subcritical flow conditions we identified four stratigraphic units unit 1 unit 2 unit 3 and unit 4 in ascending order we interpreted units 1 and 2 as having been deposited by the inflow and outflow events of the first run up and units 3 and 4 by the inflow and outflow events of the second run up respectively units 3 and 4 were more widely distributed and coarser grained than units 1 and 2 because the second run up was larger than the first run up furthermore unit 4 was more widely distributed than unit 3 because the outflow eroded the inflow deposits grain size distributions of the inflow and outflow deposits were clearly different unit 4 deposits had a peak at 2 5 phi p 1 population in contrast unit 3 deposits had a bimodal distribution with peaks at 0 5 1 5 phi p 2 population and at 2 5 phi p 1 population a comparison of the tsunami deposits with other sedimentary deposits near the study area showed that the tsunami deposits were mainly derived from the seabed at depths below 5 5 m in the offshore area where the marine sands are about 2 2 5 phi in size and thus are the source of the p 1 population the p 2 population is derived from coarse 0 5 2 phi fluvial materials eroded during the tsunami run up according to our calculations benthic foraminiferal tests were entrained from the comparatively deep seabed at depths up to 100 m during the tsunami run up and included in the tsunami deposits

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

tsunami induced sediment transport in the abyssal mediterranean sea an unusual stratigraphic unit nicknamed homogenite fills topographic lows in the complex ridge and trough bathymetry at two survey sites on the western mediterranean ridge and the calabrian ridge on near bottom 4 khz seismic reflection profiles this unit us an acoustically transparent near surface flat lying layer whereas in cores it is a homogeneous gray marl as much as 7 m thick grain size decreases upcore within the unit implying that it was deposited in a single event controlled by gravitational settling the stratigraphic position of the homogenite relative to a firmly dated sapropel bed suggests emplacement between 4400 and 3100 yr b p the source of the homogenite is inferred to be the nearby basin walls farther east two other sites with similar rugged topography lack homogenite entirely a triggering mechanism is required which is capable of initiating massive sediment transport simultaneously in many separate basins at the western two survey sites but which is not effective at the eastern sites a large archeologically recorded earthquake of the correct age is considered and rejected because its epicenter is closer to the nonhomogenite bearing sites than to the sites where this sediment type was observed and because several other earthquakes of comparable magnitude have since been recorded in the area whereas the homogenite is unique the 3 500 yr b p collapse of the caldera of the volcano of santorini caused a huge tsunami which is recorded archeologically and geologically around the eastern mediterranean because of refraction of the tsunami by the bathymetry and because the caldera collapsed in its southwest corner a disproportionate amount of tsunami energy was directed toward the western area where homogenite is observed in contrast the homogenite free sites were relatively sheltered an order of magnitude calculation shows that the near bottom oscillating currents accompanying the santorini tsunami were at or above the threshold erosion velocity at the homogenite bearing sites in addition the near bottom pressure pulse under the tsunami at the homogenite bearing sites was sufficient to cause liquefaction of sediments neither mechanism was adequate to cause sediment transport or slope failure at the homogenite free sites

review and update of the applications of organic petrology part 1 geological applications abstract organic petrology developed as coal petrology at the beginning of the 20th century dedicated mainly to the study of coals because of their utilization in industry coal petrology was then considered a branch of coal science later with the development of specialized nomenclature classification of coal components and the standardization and improvement of analytical microscopical methods this discipline expanded in interests and name becoming organic petrology organic petrology carries a broader context being as well a tool applied in the study of dispersed organic matter in sedimentary rocks due to its importance in exploration for fossil fuel resources at present organic petrology is a discipline widely recognized for its role in fundamental and applied research with respect to both coal utilization and in geosciences throughout the 20th century several important monographs have been published on the discipline of organic petrology including stach s textbook of coal petrology 1st edition 1935 2nd 1975 3rd 1982 updated as the more general organic petrology by taylor et al 1998 more recently the text applied coal petrology the role of petrology in coal utilization was published by suarez ruiz and crelling 2008 this review is the first in a two part review series that describes and updates the role of organic petrology in geosciences a second part complementing this one and focused on the applications of organic petrology to other scientific fields will follow

a detailed geomagnetic record from chinese loess abstract a collection of over 100 individually orientated hand samples was obtained from a 335 m loess section near lanzhou northern china previous studies defined the brunhes matuyama b m boundary and jaramillo normal subchron within the section the position of these magnetic markers led to the suggestion of a basal age for the section of 1 3 ma this disagrees significantly with a date of 2 45 ma for the onset of loess accumulation at lochuan 500 km to the east of lanzhou the present study considers the section in far greater detail and has derived a complex magnetostratigraphy isolating seven normal events within the lower 130 m of the section a simple interpretation of this magnetostratigraphy suggests a basal age for the section in the region of 2 4 ma however the relative chronology of the loess palaeosol sequence although appearing to confirm this basal age has revealed that this simple interpretation of the magnetostratigraphy may not be justified

influence of nearshore sediment dynamics on the distribution of heavy mineral placer deposits in sri lanka beach sediments in sri lanka contain industrial grade heavy mineral occurrences samples of both offshore and onshore sediments were collected to examine the provenance mineralogy and geochemical compositions of the heavy mineral occurrences coastal morphodynamic changes along the coastline of sri lanka were analyzed using the time series satellite images these coastal morphodynamic changes were used to identify the prominent directions of monsoon influenced longshore currents coastal sediment accretion and depositional trends and their relationships to the provenance of the heavy minerals results show the concentrations of detrital ilmenite zircon garnet monazite and rutile vary in the onshore and offshore sediments the heavy mineral potential of the northeastern coast is high average contents of about 45 50 in the verugal deposit 70 85 in the pulmoddai deposit and 3 5 5 0 in offshore samples stretching from nilaveli to kokkilai compared to sediments in southwest average content about 10 in onshore sediments and 2 in offshore sediments from the mouth of the gin river therefore no economic grade heavy mineral placers were identified in the offshore environments the high concentrations of heavy minerals in beach sediments and low concentrations in offshore sediments suggest operation of a panning system in the surf zone to form enriched placer deposits major and trace element compositions of beach sediments show marked enrichments of tio2 fe2o3 la ce zr cr nb th and v compared to average upper continental crust ucc values analysis of prominent coastal longshore transport patterns identifies bidirectional sediment transport in the northeast coast of sri lanka in the southwestern coast two transport directions occur with anti clockwise transport from galle to hambantota and clockwise transport from hikkaduwa to wadduwa the heavy minerals in the placers were mainly derived from precambrian metamorphic rocks and transported to the coast through the river systems of sri lanka

age and palaeoclimatic significance of the loess of lanzhou north china extending in a broad arc that abuts the sandy non gobi deserts the loess plateau of northern china1 3 is one of the most massive accumulations of loess in the world the loess sequence is typically characterized by an alternation of silty or sandy loess with more clay rich palaeosols these alternations in conjunction with their enclosed faunas and distinctive mineralogies have been interpreted as reflecting pleistocene glacial interglacial cycles3 8 because it holds implications for the climatic and anthropological history of china9 10 the definition of a reliable chronological framework for loess deposition is of great interest recent palaeomagnetic studies4 5 have indicated that loess deposition in shaanxi province commenced 2 4 myr ago to assess the synchrony of loess accumulation across the loess plateau we have dated a 330 m thick loess sequence near lanzhou gansu province the magnetostrati graphical results reported here indicate that the base of this loess succession dates from 1 3 my r ago this young age in comparison to the shaanxi sequence is attributed to uplift along the northern fringe of the tibetan plateau11 that precluded early pleistocene loess preservation in this mountainous region palaeosols in the basal loess occur on average once every 25 kyr suggesting that climates conducive to soil forming events may have been modulated by orbital precession in the early pleistocene

geological and geochemical characteristics of marine continental transitional shale from the upper permian longtan formation northwestern guizhou china abstract organic rich shale deposited in a marine continental transitional facies was well developed in the upper yangtze area during the late permian it is considered to contain a large amount of shale hydrocarbon resources this paper takes the upper permian longtan shale in the central guizhou uplift as an example to characterize the transitional shale reservoir based on organic geochemistry data x ray diffraction xrd analysis and scanning electron microscopy sem observation the geochemical characteristics of this transitional shale were systematically studied and the shale gas potential was investigated the results indicate that the longtan shale has fair to good hydrocarbon potential with high total organic carbon toc and contains type iii gas prone organic matter its high thermal maturity favors the generation of gas ro 1 10 2 74 xrd analyses show that the mineral components of the transitional shale are dominated by high clay content 58 7 wt the clay minerals are dominated by illite 44 and mixed illite smectite 43 sem observation shows that intra particle pores inter particle pores and microfracture were well developed in the longtan shale which can provide reservoir space for the accumulation of shale gas organic matter pores appear rare due to its organic type in summary the longtan shale has high organic content high maturation and high gas content all of which demonstrate its great potential as a shale gas resource but the high clay content of the longtan shale may be a challenge to shale gas production

a numerical model for tsunami induced morphology change we describe the development of a time resolved model for tsunami induced morphology change based on an existing boussinesq model for weakly dispersive free surface waves coupled to a depth integrated model for sediment concentration and an equation for bed level change the model allows for spatial variability in bottom friction coefficients and accounts for the presence of non erodible beds or finite depths of available sediment the model is verified using one laboratory data set and against field observations of morphology change in the crescent city ca harbor during the 2011 tohoku tsunami event the model is then applied to a hypothetical example illustrating the impact of tsunami inundation on an undeveloped barrier island

recovery from a large tsunami mapped over time the aceh coast sumatra this is a record of the rapid recovery of the aceh coast northwest sumatra after its destruction in the tsunami of 26 december 2004 using high resolution ikonos images and field visits we mapped the same 175 km of coastline at 1 m resolution five times 2003 before the tsunami 2004 and early 2005 immediately after the tsunami 2006 2007 and 2008 the aceh coast was eroded back for about 500 m in the tsunami except at the rocky headlands and almost the entire suite of depositional landforms of beaches low sand dunes and wetlands were removed a new coast started to appear within weeks closely resembling the pre tsunami version the new suite of depositional forms not only masked the erosional effect of the tsunami within a very brief period but also mimicked the old coast the post tsunami coast was subjected to the normal coastal processes and the new coast was formed within the constraints of the prevalent coastal environment thus resembling the old one the new beaches tend to be bigger than the old one although they have not yet reached their former seaward positions on this coast a tsunami appears to be an episodic destructive event at an interval of 500 years followed by a set of geomorphic processes that rapidly tend to remove or mask the evidence of such destruction the recovery is hindered where anthropogenic influences have modified the coastal forms and configuration we suggest that a the optimal management of coasts of this type after a tsunami is to leave it to nature and b sedimentary deposits are better indicators of past tsunamis than coastal morphology as demonstrated high resolution satellite images can be used not only for measuring changes caused by a high magnitude event but also for tracing the recovery over time this was impossible earlier except for very small areas which could be mapped on foot

insights into the effects of matrix retention and inert carbon on the petroleum generation potential of indian gondwana shales abstract the rock eval pyrolysis and total organic carbon toc analysis technique is widely used for organic geochemistry screening of source rocks and potential unconventional petroleum reservoirs the rock eval derived parameters the hydrogen index hi which is the ratio between hydrocarbons released under the s2 curve hydrocarbon formed by thermal pyrolysis s2 is an indicator of petroleum generation potential and total organic carbon toc can be used to infer the type of organic matter present in a rock however hi is often under estimated due to retention of some hydrocarbons included under the s2 curve by the rock matrix and the presence of inert carbon within the rock here we describe and correct the matrix retention and inert carbon effects on hydrocarbon generation from a suite of shale samples from indian gondwana shale reservoirs removal of the petrographically identified inert carbon component from the samples tested leads to less scatter in the toc s2 relationship obtained the ratio of volume percentage of organic matter identified through optical microscopy to toc is calculated and that ratio was least in the one heat affected sample but higher in low toc shales 12 5 with decreasing toc content in the sample set analyzed the corrected hi values calculated using the s2 toc intercept increase significantly this correction can therefore lead to false indications about the type of organic matter present a key novel finding of this work is the need while correcting hi for matrix retention effects to consider samples with a specific range of toc contents and to match them to the kerogen types present e g types iii and iv in the samples analyzed filters should also be applied to adjust for the degree of thermal maturity and organic facies

critical considerations when assessing hydrocarbon plays using rock eval pyrolysis and organic petrology data data quality revisited abstract the dramatic increase in exploration for unconventional hydrocarbon resources has inherently fuelled the need for new source rock geochemical data the need for new data comes along with an increasing number of new users many of whom do not possess the background to interpret accurately and evaluate the quality of data sets generated by different geochemical screening techniques e g rock eval pyrolysis vitrinite reflectance here datasets from rock eval pyrolysis vitrinite reflectance and leco toc analyses are scrutinized and compared to show how failing to recognize good vs bad datasets can dramatically change interpretations during prospect or play appraisals detector saturation contamination of the sample with drilling fluid and suppression of both tmax and vitrinite reflectance are examples of complications that could compromise the validity of the results and the play or prospect reviews derived from them in addition misconceptions such as leco toc is better than rock eval 6 toc expressed by many users are a consequence of the lack of understanding of how different screening techniques and instrumentation work a solid understanding of these pitfalls and limitations can provide inexperienced geoscientists and engineers with the required support to improve risk maps for hydrocarbon charge analysis and source rock evaluations when using classic guidelines for interpreting results

erosion and sedimentation in kalpakkam n tamil nadu india from the 26th december 2004 tsunami abstract laterally extensive sand sheets deposited by the 26th december 2004 asian tsunami provide a valuable modern analogue for comparison with wash over deposits of unknown origin in many places on the east coast of india distinct deposits of marine sand drape the landscape and overlie the muddy soils of the coastal plain this paper discusses detailed measurements of coastal topography tsunami flow height and deposit thickness made at kalpakkam india five transects were examined in detail to assess the sedimentology and spatial distribution of the tsunami deposit near the mean water line the tsunami eroded approximately 10 25 cm of sand from the beach and berm at kalpakkam the sand sheet deposited by the tsunami begins 25 m from the shore extending 420 m inland where it becomes thin and patchy approximately 30 m from the limit of inundation in some cases the deposit consists of 2 to 4 normally graded units with coarse sand near the base and fine sand at the top a characteristic observed in many tsunami deposits worldwide in many places the deposits also contain numerous thin laminated units a characteristic usually associated with storm over wash the presence of the laminated beds is indicative of the complexity of tsunami sedimentation on the coast such observations are essential to the formation of definitive facies models for palaeo overwash studies that are capable of distinguishing between sediments deposited by storms or tsunami

traces of tsunami preserved in inter tidal lacustrine and marsh deposits some examples from northeast japan the japan sea earthquake of may 26 1983 triggered a large scale tsunami that surged over the coast of ne japan and caused considerable damage the tsunami resulted in peculiar sedimentary processes on the coast depending on the hydraulic scale of the tsunami three kinds of sedimentary processes were recognized each of which left unique deposits such deposits are expected to remain in sedimentary sequences preserving remarkable sedimentary facies borehole samples drilled at different localities in coastal regions have been examined to detect traces of ancient tsunamis sedimentological and geochemical studies of the samples reveal that layered deposits similar to those developed by the tsunami of the japan sea earthquake are common in the drilled cores estimated ages of these deposits are exactly equivalent to the dates of ancient tsunamis documented in historical records these results show that the invasion of tsunamis is recorded in coastal depositional sequences from analyses of long borehol

comparative organic petrology of interlayered sandstones siltstones mudstones and coals in the upper carboniferous ruhr basin northwest germany and their thermal history and methane generation in the coal mining ruhr area upper carboniferous rocks ca 4000 m consist of interlayered sandstones siltstones mudstones and coals they were deposited in a tropical paralic environment where alternating fluvial sedimentation occasional marine ingressions and swamp growth resulted in an irregular cyclic succession the total sedimentary package contains on an average 6 vol of organic matter about 70 vol of the organic matter occurs in coal seams the rest as dispersed organic matter in clastic rocks the organic matter is autochthonous in the coals and allochthonous in associated sandstones and siltstones it consists of about 70 vitrinite 20 inertinite and 10 liptinite the overall maceral group composition is the same for coals and dispersed organic matter this surprising similarity is caused by a nearly exclusive input of land plant derived organic matter to swamps and fluvial systems and a similar degree of preservation highest average liptinite contents of total macerals were found in unrooted mudstones highest average inertinite contents in coarse grained siltstones and highest average vitrinite percentages in sandstones

sediment sources and sedimentation processes of 2011 tohoku oki tsunami deposits on the sendai plain japan insights from diatoms nannoliths and grain size distribution abstract the 11th march 2011 tohoku oki tsunami inundated the low lying sendai plain japan more than 5 km inland leaving sand and mud deposits over most of the area in order to establish the sources of the tsunami deposits and interpret processes of their sedimentation samples were collected from the deposits underlying soils and the beach along a shore perpendicular transect and analysed for grain size diatom assemblages and nannoliths the fining inland tsunami deposits consisted of poorly to moderately sorted medium to coarse sand within 2 km of the coastline and very poorly to poorly sorted mud farther inland more specifically there was a slight fining of the coarse to medium sand mode within the sandy deposits and an increased contribution of the coarse and very coarse silt fraction in the mud deposits the tsunami deposits also exhibited vertical changes including fining upward and coupled coarsening fining upward trends few diatoms were present in beach sediments soils and tsunami deposits within 1 km of the coastline while diatoms were more abundant farther inland diatom assemblages in the soil and tsunami deposits were similar and dominated by species typical of freshwater brackish habitats while no typically marine species were encountered nannoliths were generally absent in the studied sediments except for few specimens our data indicate that there was probably no or only a very minor component of marine sediments transported onland by the tsunami the sandy tsunami deposits within 1 km of the coastline were mostly derived from beach and dune erosion from 1 to 2 km landward the contribution of these sources decreased while sources comprising local soil erosion and the entrainment of sediments from the teizan bori canal increased farther inland local soil erosion was the major sediment source for the mud deposits the tsunami deposits were most likely deposited during at least two inundations mostly out from suspension resulting in an upward grain size fining trend however bed load deposition was also important in the sandy deposits as suggested by a common grain size upward coarsening position on c m diagrams and frequent horizontal lamination the present study reveals that even very large tsunamis may not transport marine sediments onland and thus many commonly applied indicators of tsunami deposits based on the assumption of their offshore origin marine diatoms foraminifera nannoliths marine sediments may be of limited use

truncated flame structures within a deposit of the indian ocean tsunami evidence of syn sedimentary deformation this study reveals the three dimensional morphology and syn sedimentary formation processes of a deformation structure termed truncated flame structures which is found in a terrestrial tsunami deposit in southern thailand that formed during the 2004 indian ocean tsunami the structure was found at the boundary between a lower fine grained layer and an upper coarse grained layer that are related to two runup events in order to confirm the morphology of the structure the authors excavated two trenches and an opencast pit when viewed in a cross section oriented parallel to the direction of the runup current the deformed boundary has an irregularly bulging profile similar to that observed in flame structures the protruding structures are inclined towards the downstream direction of the runup current and are truncated horizontally along their upper surface by parallel laminations in the overlying layer when viewed in a cross section oriented perpendicular to the current direction it appears that parts of the upper layer descend into the lower layer as lobate masses in places these masses are completely detached from the main part of the upper layer forming circular or elliptical shapes the contact between the lower layer and the main part of the upper layer is a planar truncation surface opencast excavation of the contact surface revealed that the deformed structures have flat sinuous horseshoe crests that open in a downstream direction it is possible for the runup current to generate shear stress such that it deforms the boundary into a truncated flame structure moreover the observations made in this study indicate the syn sedimentary development of the structure deformation and truncation occurred simultaneously in association with the runup current that formed the upper layer truncated flame structures can be used as a criterion in identifying the syn sedimentary deformation of substrate the structures are indicative of unidirectional flow with sufficiently high shear velocity to deform unconsolidated substrate as in the present case the truncated flame structures may be characteristic of tsunami events that involve strong unidirectional currents on land due to the extraordinarily long wave period of tsunamis rather than other events such as storm surges or flooding

geological effects of tsunami on mid ocean atoll islands the maldives before and after the sumatran tsunami low lying coral islands are fragile landforms susceptible to long term sea level rise and extreme events such as hurricanes and tsunamis the sumatran earthquake of 26 december 2004 generated waves that reached the maldives 2500 km away observations of the effects of the tsunami are presented here based on pre and post tsunami topographic and planform surveys of 13 uninhabited maldivian islands the surveys showed there was no substantial island erosion and no significant reduction in island area rather the tsunami accentuated predictable seasonal oscillations in shoreline change including localized retreat of exposed island scarps by up to 6 m deposition of cuspate spits to leeward and vertical island building through overwash deposition of sand sheets up to 0 3 m thick covering up to 17 of island area these results have implications for island stability indicating that low lying reef islands are physically robust and the geological signature of tsunamis on atoll island development is minor

onshore tsunami deposits caused by the 1993 southwest hokkaido and 1983 japan sea earthquakes onshore tsunami deposits resulting from the 1993 southwest hokkaido and 1983 japan sea earthquakes were described to evaluate the feasibility of tsunami deposits for inferring paleoseismic events along submarine faults tsunami deposits were divided into three types based on their composition and aerial distribution a deposits consisting only of floating materials b locally distributed siliclastic deposits and c widespread siliclastic deposits the most widely distributed tsunami deposits consist of the first two types type c deposits are mostly limited to areas where the higher tsunami runup was observed the scale of tsunami represented by vertical tsunami runup is an important factor controlling the volume of tsunami deposits the thickest deposits about 10 cm occur behind coastal dunes to produce thick siliclastic tsunami deposits a suitable source area such as sand bar or dune must be available in addition to sufficient vertical tsunami runup estimation of the amounts of erosion and deposition indicates that tsunami deposits were derived from both onshore and shoreface regions the composition and grain size of the tsunami deposits strongly reflect the nature of the sedimentary materials of their source area sedimentary structures of the tsunami deposits suggest both low and high flow regimes consequently it seems very difficult to identify tsunami deposits based only on grain size distribution or sedimentary structure of a single site in ancient successions

simple kinetic models of petroleum formation part i oil and gas generation from kerogen modern basin analysis uses kinetic models to predict the extent of petroleum generation within potential source rocks the global kinetic model presented here assigns kinetic parameters based on gross depositional environment and stratigraphic age this is useful in areas of low geochemical knowledge including exploration frontiers five kerogen kinetic organofacies each characterized by a specific organic matter input and early diagenetic overprint can broadly be related to sedimentary facies age associations even using seismic sequence stratigraphy alone a aquatic marine siliceous or carbonate evaporite any age b aquatic marine siliciclastic any age c aquatic non marine lacustrine phanerozoic d e terrigenous non marine ever wet coastal mesozoic and younger and f terrigenous non marine coastal late palaeozoic and younger routine pyrolysis data allow partitioning of organic carbon in the immature source rock into four initial components oil oil generative gas generative and inert separate kinetic parameters for the oil and gas generative fractions allow computation of the evolving concentration and composition of the products it was assumed that the activation energy distributions for each fraction were normally distributed non linear regression of large combined laboratory and field data sets varying by up to 12 orders of magnitude in heating rate established optimum values for the required ten 5 2 kinetic parameter sets a emean e differences in kinetic parameters can be reconciled with known chemical properties although our knowledge base is still inadequate to construct kinetic models from first principles mean activation energies governing oil generation increase systematically in the order a f causing a corresponding increase in generation temperature at a reference heating rate 2 c ma 1 the oil generation window 10 90 oil generative kerogen degraded increases from ca 95 135 c to 145 175 c organofacies c has the tightest energy distribution and narrowest oil generation window the gas generation window ranges from ca 105 155 c to 175 220 c thermal stress results from a combination of temperature and time an order of magnitude increase decrease in heating rate elevates depresses reaction temperatures by ca 15 c heating rates in subsiding sedimentary basins can vary by two orders of magnitude dramatic differences in generation temperature can result if the heating rate and organofacies effects compound thus global oil and gas generation temperature thresholds constitute blunt instruments with which to screen the petroleum potential of sedimentary basins because unexpelled oil provides a potential feedstock for oil to gas cracking in the source rock quantitative models of petroleum generation become really useful only when coupled with models of oil gas cracking and expulsion for example the frequently observed association between gas provinces and coals cannot be explained solely by their generation behaviour

loess stratigraphy in central china abstract the loess deposits in central china record world wide climate changes of the last 2 5 ma numerous climatic oscillations are marked by alternating loess and soil units with continuous coverage of the matuyama and brunhes epochs magnetic susceptibility of the deposits correlates closely with the oxygen isotope record of the deep sea sediments and provides an independent measure of climate and time the key marker bed of the chinese loess sequence is the paleosol s5 the time equivalent of the mid brunhes oxygen isotope stages 13 14 and 15 it marks a prolonged interval of warm humid climate lasting from approximately 615 to 470 thousand years ago several episodes of river downcutting coincide with deposition of the exceptionally thick loess units l1 oceanic oxygen isotope stages 2 to 4 l2 stage 6 l5 stage 12 l6 stage 16 l9 stage 22 l15 stage 38 about 1 15 ma and ws4 about 2 3 ma these erosional events are interpreted as a result of episodic uplift of the loess plateau the deposition of the earliest loess layers between 2 5 and 2 3 ma ago marks a first order shift from warm and humid environments toward harsh continental steppes comparable to those of the middle and late pleistocene little if any lithologic or paleontologic changes were noted within or above the olduvai magnetozone so that the proposed plio pleistocene boundary at approximately 1 65 ma has no lithostratigraphic and biostratigraphic representation in the chinese loess series comparison with the deep sea drilling program core 552a in the north atlantic and with the santerno river section near bologna shows that the occurrence of the earliest loess in china coincides with the timing of the first significant ice rafting in the north atlantic and with the appearance of cold water foraminifers in the marine deposits of northern italy an extension of the stage system of the oxygen isotope signal extended back to the gauss matuyama boundary is proposed

preliminary study of quaternary tectono climatic cycles in china major cycle ii this started in the middle part of the aggradation of early pleistocene lacustrine and fluviolacustrine beds nihewan yuanmou and qiangtant formations and ceased with the deposition of the top part of these strata during this cycle the second glacial stage corresponding to the shizishan glacial stage of the east kunlun mountains is essentially indicated by sporepollen assemblages and periglacial phenomena reflecting a cold climate until the second interglacial stage or the late part of it intense tectonic movements also named nihewan yuanmou and qiangtang movements occurred simultaneously all over the country and interrupted the development of early pleistocene lakes the timing is shown by magnetostratigraphy and began near the gauss matuyama boundary and ended after the olduvia event major cycle i this began about 3 4 ma ago when global climate became colder and continued to about 2 4 ma bp corresponding more or less with the entire gauss epoch the moraines and the fluvioglacial or periglacial sediments representing the first glaciation rest mostly unconformably on bedrock including pliocene sequences with partial conformity in places overlying fluviolacustrine beds are generally in overlapping or transitional relationship with them for example it can be seen that the sammen movement marking the end of major cycle i led to a break in the sedimentation in the ancient sanmen lake of the sanmenxia area on yellow river cao et al 1983 several boundaries between the various cyclothems stratigraphically and geomorphologically using magnetostratigraphy and climatostratigraphy the boundaries between three major cycles can be established as follows

effects of landforms on tsunami flow in the plains of banda aceh indonesia and nam khem thailand abstract mapping on high resolution satellite images and in the field shows differences in landforms and characteristics of tsunami flow on two contrasting coastal plains following the giant earthquake on december 26 2004 the plain of banda aceh on the northern tip of the sumatra island indonesia and the nam khem plain in the andaman sea coast of thailand the landforms of the banda aceh coastal plain are characterized as deltaic lowland with tidal plains in the western and central parts and strand plain with beach ridges in the eastern part the run up tsunami flow invaded areas about 3 4 km from the coast strong tsunami flow severely damaged the tidal plain and the landforms along the coast except coastal dunes in the east most of the landforms except sand dunes along the coast had almost no effect on the protection against the tsunami but the higher micro landforms such as beach ridges and natural levees prevented the flow of the tsunami from its invasion into the inland near the end of tsunami inundation the tsunami inundation spread out over the entire nam khem coastal plain with an average depth of 4 5 m the direction of run up flow was almost perpendicular to the coastline whereas backwash flow directions were controlled by topography backwash flow was concentrated in the lower portions of the plain for example in small stream channels wedge shaped channels in the lower parts of the streams were formed due to the concentration of backwash flow the existence of the swales between parallel beach ridges corresponds well with the distribution of thick tsunami deposits coastal erosion of the plain was caused by the direct attack of tsunami waves and the lower reaches of small rivers were eroded by strong backwash flow

coalbed methane characteristics of gates formation coals northeastern british columbia effect of maceral composition the majority of research reported on methane adsorption characteristics of coal seams has focused on vitrinite rich coals however western canadian coals are more inertinite rich than those of the western united states and are shown to differ in gas adsorption characteristics the influence of maceral composition upon gas adsorption characteristics of medium volatile coal samples from the middle cretaceous gates formation of northeastern british columbia was investigated lithotype coal facies samples were analyzed for surface area maceral and mineral composition and methane adsorption standard coal analyses were also performed proximate low temperature ash and equilibrium moisture the vitrinite content of the samples analyzed ranges from 18 to 95 vol min ral matter free the ash yield varies from 4 4 to 33 7 wt both maceral composition and mineral matter content have an important influence on adsorption characteristics as indicated by carbon dioxide surface areas and methane adsorption isotherms on a mineral matter free basis the amount of methane adsorbed generally increases with vitrinite enrichment the lowest methane adsorption occurs in the sample with the highest inertinite content carbon dioxide surface areas of the lithotypes range from 87 to 176 m2 g on a raw coal basis and from 99 to 184 m2 g on a mineral matter free basis surface area generally decreases with increased mineral matter content and increases with increased vitrinite content the increase in adsorption of both methane and carbon dioxide with increased vitrinite concentration is interpreted a resulting from differences in the pore size distribution of vitrinite and inertinite vitrinite is predominantly microporous whereas inertinite is meso to macroporous the monolayer volumes of carbon dioxide as calculated from the dubininradushkevich equation are higher than those of methane as determined from the langmuir equation but are correlated the methane adsorption isotherms and surface area data indicate that the maceral compositional variations in coal are at least as significant as coal rank in determining the potential volume of adsorbed methane and thus the coalbed methane potential of a deposit

tsunami as agents of geomorphic change in mid ocean reef islands low lying atoll islands appear highly vulnerable to the effects of climate change and extreme natural events potentially disastrous effects of future sea level rise have been inferred in many studies and the actual impacts of tropical storms on island destruction and formation have been well documented in contrast the role of tsunami in the geomorphic development of atoll islands has not been investigated the sumatran earthquake of 26 december 2004 generated a tsunami that reached the maldives 2500 km away with waves up to 2 5 m high observations on the geomorphic changes resulting from the tsunami are detailed here based on pre and post tsunami profile measurements of island beach and reef topography and gps surveys of the planform shape of islands and beaches of 11 uninhabited islands in south maalhosmadulu atoll maldives erosional and depositional impacts were observed on all islands and these have been quantified in general the changes were of a minor nature with a maximum reduction in island area of 9 and average of 3 75 rather the tsunami accentuated predictable seasonal oscillations in shoreline change including localised erosion reflected in fresh scarps and seepage gullies depositional features in the form of sand sheets and sand lobes emplaced on the vegetated island surfaces provide clear evidence that the tsunami waves washed over parts of all the islands both erosional scarps and overwash deposits were concentrated at the tsunami exposed eastern sides of the islands impacts on leeward shores were primarily accretionary in the form of spit and cuspate foreland extension whereas the nature and magnitude of intra and inter island impacts was variable an east to west decline in aggregate effects was noted detailed consideration of the morphodynamic interaction between the tsunami waves and island morphology show that this cross atoll gradient resulted not just from the reduction in tsunami energy as it passed through the atoll but also from variations in elevation of the encircling island ridge and the quantity and distribution of sediment in the antecedent beach a conceptual model identifying the sequence of changes to individual islands supports the observational data and the pattern of geomorphic changes resulting from the tsunami this model leads to consideration of the longer term impacts of the tsunami on the future stability of islands four scenarios are presented each of which has a different island beach sediment budget and different relaxation time to achieve dynamic equilibrium

sedimentology of the december 26 2004 sumatra tsunami deposits in eastern india tamil nadu and kenya the december 26 2004 sumatra tsunami caused severe damage at the coasts of the indian ocean we report results of a sedimentological study of tsunami run up parameters and the sediments laid down by the tsunami at the coast of tamil nadu india and between malindi and lamu kenya in india evidence of three tsunami waves is preserved on the beaches in the form of characteristic debris accumulations we measured the maximum run up distance at 580 m and the maximum run up height at 4 85 m flow depth over land was at least 3 5 m the tsunami deposited an up to 30 cm thick blanket of moderately well to well sorted coarse and medium sand that overlies older beach deposits or soil with an erosional unconformity the sand sheet thins inland without a decrease of grain size the deposits consist frequently of three layers the lower one may be cross bedded with foresets dipping landward and indicating deposition during run up the overlying two sand layers are graded or parallel laminated without indicators of current directions thus it remains undecided whether they formed during run up or return flow thin dark laminae rich in heavy minerals frequently mark the contacts between successive layers benthic foraminifera indicate an entrainment of sediment by the tsunami from water depths less than ca 30 m water depth on the indian shelf these depths are present at distances of up to 5 km from the coast in kenya only one wave is recorded which attained a run up height of 3 m at a run up distance of ca 35 m from the tidal water line at the time of the tsunami impact only one layer of fine sand was deposited by the tsunami it consists predominantly of heavy minerals supplied to the sea by a nearby river the sand layer thins landward with a minor decrease in grain size benthic foraminifera indicate an entrainment of sediment by the tsunami from water depths less than ca 30 m water depth reaching down potentially to ca 80 m the presence of only one tsunami related sediment layer in kenya but three in india reflects the impact of only one wave at the coast of kenya as opposed to several in india grain size distributions in the indian and kenyan deposits are mostly normal to slightly positively skewed and indicate that the detritus was entrained by the tsunami from well sorted pre tsunami deposits in nearshore swash zone and beach environments

assessment of organic richness and hydrocarbon generation potential of raniganj basin shales west bengal india abstract high energy prices and severe energy shortage has led shale gas to become the focus of study and exploration in many countries india like many other countries around the world with shale gas potential recognizes the strategic importance of developing its shale gas resources for the purpose of shale gas assessment the authors have selected sixty six borehole shale samples of different formations from different parts of raniganj basin west bengal india rock eval pyrolysis and total organic carbon toc analysis and petrographic characterization of the shales were carried out shales from barakar lower permian barren measures upper permian and raniganj formation upper permian are marked by good to excellent toc content input of type iii organic matter and are capable of generating oil and thermogenic gas upon thermal cracking igneous intrusives dykes and sills in the formations occurring in and around the areas of sitarampur si and kulti ku in western part of the basin might have resulted in cooking of the shales increasing their maturities estimated vitrinite reflectance vro as indicated by the barren measures shales of shallow depths from the above mentioned areas majority of the samples are marked by low oxygen index oi values

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

evaluation of tsunami impacts on shallow marine sediments an example from the tsunami caused by the 2003 tokachi oki earthquake northern japan abstract a combined approach of field geology and numerical simulation was conducted for evaluating the tsunami impacts on the shelf sediments the 2003 tokachi oki earthquake m 8 0 that occurred on 25 september 2003 off southeastern hokkaido northern japan generated a locally destructive tsunami maximum run up height of the tsunami waves reached 4 m above sea level in order to estimate the tsunami impacts on shallow marine sediments we compared pre and post tsunami marine sediments in water depths of 38 112 m in terms of grain size sedimentary structure and microfossil content decreases of fine fractions especially finer than very fine sand which led to coarsen the mean grain size were detected in the inner shelf of the northern part of the study area foraminiferal assemblages also changed in the coarsened sediments on the other hand the other shelf sediments largely unchanged or slightly fined we also simulated the tsunami wave velocity and direction and grain size entrained by the modeled tsunami the numerical simulation resulted in that the 2003 tsunami could transport very fine sand in water depths shallower than 45 95 m at the northern part of the study area this is comparable with the actual grain size changes after the tsunami had passed however some storms and tidal currents might also be possible to stir the surface sediments after the pre tsunami survey so we could not conclude that the grain size changes had been caused only by the tsunami nevertheless a combined approach of sampling and modeling was powerful for estimating the tsunami impacts under the sea

numerical simulation of sedimentation and erosion caused by the 2011 tohoku tsunami in oarai port japan abstract the 2011 tohoku tsunami induced sediment deposition of 334 000 m3 mainly in the basin and 9 m erosion at the tips of a breakwater and a groin in oarai port japan the tsunami induced bathymetry change was simulated using a numerical model and the simulated bathymetry change was compared with the measured one the comparison showed that the simulated bathymetry change quantitatively agreed with the measured one including the sediment deposition and the erosion mentioned above although the erosion measured along the breakwater was not well reproduced by the model the time series of simulated bathymetry change water level current and suspended sediment concentration showed that the sediment deposition in the center of the basin was mostly induced by the sediments that moved into the basin through its entrance between the breakwater and the groin and were redistributed by counterclockwise vortices the severe erosion at the tip of the breakwater was mainly induced by the strong southward currents

tsunami sediments and their foraminiferal assemblages abstract tsunami hazard assessment begins with a compilation of past events that have affected a specific location given the inherent limitations of historical archives the geological record has the potential to provide an independent dataset useful for establishing a richer chronologically deeper time series of past events recent geological studies of tsunami are helping to improve our understanding of the nature and character of tsunami sediments wherever possible geologists should be working to improve the research tool kit available to identify past tsunami events marine foraminifera single celled heterotrophic protists have often been reported as present within tsunami deposited sediments but in reality little information about environmental conditions and by analogy the tsunami that deposited them has been reported even though foraminifera have an enormous capacity to provide meaningful palaeo environmental data here we review what foraminifera are describe their basic form and significance summarise where they have been reported in tsunami sediments and identify what can be learnt from them we review the gaps in our understanding and make recommendations to assist researchers who examine foraminiferal assemblages in order to enhance their use within tsunami geology

tsunami deposits in holocene bay mud in southern kanto region pacific coast of central japan abstract tsunami have probably deposited sand sheets that are intercalated in holocene bay floor mud exposed on the boso and miura peninsulas facing the convergent boundary of the pacific philippine sea and eurasian plates we have identified seven sand sheets at four drowned valleys and correlated these by 137 radiocarbon dates of shells and wood the sheets consist of poorly sorted muddy sand and well sorted sand layers in fining upward sequences containing abundant transported shells rip up clasts and wood fragments the sheets erosionally overlie bioturbated bay floor mud that contains molluscan shells in life position most of the sheets are less than 20 cm thick and rarely more than 50 cm thick some molluscan shells are older in these layers than in underlying mud both landward and seaward paleocurrents are shown in a few cases by imbrication of shells and by low angle wedge shaped lamination at least five of the sand sheets contain molluscan fossils derived from rocky coasts or shore platforms although they intercalated in mud deposited within bays at depths of 10 15 m two other sand sheets are dominated by open seashore ostracode assemblages although they were deposited in the brackish inner bay and muddy central bay five of the layers may correlate with emergences recorded by nearby holocene marine terraces these correlations suggest that great earthquakes triggered the inferred tsunami the tsunami occurred at intervals of 300 2000 years beginning about 10 000 years ago

tsunamis as geomorphic crises lessons from the december 26 2004 tsunami in lhok nga west banda aceh sumatra indonesia abstract large tsunamis are major geomorphic crises since they imply extensive erosion sediment transport and deposition in a few minutes and over hundreds of kilometres of coast nevertheless little is known about their geomorphologic imprints the december 26 2004 tsunami in sumatra indonesia was one of the largest and deadliest tsunamis in recorded human history we present a description of the coastal erosion and boulder deposition induced by the 2004 tsunami in the lhok nga bay located to the west of banda aceh northwest sumatra the geomorphological impact of the tsunami is evidenced by beach erosion some beaches have almost disappeared destruction of sand barriers protecting the lagoons or at river mouths numerous erosion escarpments typically in the order of 0 5 1 5 m when capped by soil and more than 2 m in dunes bank erosion in the river beds the retreat along the main river is in the order of 5 15 m with local retreats exceeding 30 m large scars typically 20 50 cm deep on slopes dislodgement of blocks along fractures and structural ramps on cliffs the upper limit of erosion appears as a continuous trimline at 20 30 m a s l locally reaching 50 m the erosional imprints of the tsunami extend to 500 m from the shoreline and exceed 2 km along riverbeds the overall coastal retreat from lampuuk to leupung was 60 m 550 000 m 2 and locally exceeded 150 m over 276 000 m 3 of coastal sediments were eroded by the tsunami along the 9 2 km of sandy coast the mean erosion rate of the beaches was 30 m 3 m of coast and locally exceeded 80 m 3 m the most eroded coasts were tangent to the tsunami wave train which was coming from the southwest the fringing reefs were not efficient in reducing the erosional impact of the tsunami the 220 boulders measured range from 0 3 to 7 2 m large typically 0 7 1 5 m with weights from over 50 kg up to 85 t we found one boulder less than 1 m large at 1 km from the coastline but all the others were transported less than 450 m 30 m and the moderate tsunamis height