insights into subduction related uplift along the hikurangi margin new zealand using numerical modeling 1 we investigate the causes of regional uplift along the hikurangi margin north island new zealand late quaternary rock uplift rates and postglacial fluvial incision rates delineate broad changes in rock uplift pattern along the margin comparison with the neogene rock uplift rates the erosion surface on basement and the margin morphology suggests that these uplift patterns are long lived and relate to deep seated subduction processes we use two dimensional numerical finite element models to place constraints on margin geometry and uplift rates resulting from subduction processes inferred to drive regional uplift the models indicate that subduction of relatively buoyant and thick hikurangi plateau crust is the most likely mechanism for low rates 1 mm yr 1 of uplift along the entire margin sediment underplating is probably the major cause of higher rates of uplift of the central and northern axial ranges 2 4 mm yr 1 seamount subduction could account for short wavelength zones of higher uplift rate on the order of 1 mm yr 1 and could contribute to tectonic erosion which may be driving uplift in the northern margin this study shows the value of using numerical models to link regional patterns of rock uplift and surface morphology to deep seated subduction processes

generation of gas and oil from coal and other terrestrial organic matter abstract late carboniferous permian sedimentary rocks contain the world s largest coal reserves which have generated and released gas but little if any oil in comparison organic matter deposited in lacustrine fluvial deltaic or brackish water sediments has sourced large quantities of waxy oils in countries such as china australia the u s a argentina venezuela and indonesia plus gas and condensate in deltas worldwide why is more oil coming from land derived organic matter disseminated in sediments than from the carboniferous permian coal beds which also are land deposits the answer appears to be in the hydrogen content and the ease of migration when organic matter and coals have high hydrogen contents relative to carbon they can form oil when the hydrogen is low mainly gas is formed most of the world s coal is low in hydrogen whereas much of the terrestrial organic matter disseminated in sediments is higher in hydrogen so it forms more oil also both gas and oil are adsorbed on coal more strongly than on the disseminated kerogen of sedimentary rocks this makes migration of oil out of the coal more difficult compared to migration from conventional shale source rocks

coseismic uplift of holocene marine terraces in the pakarae river area eastern north island new zealand abstract holocene marine terraces along 15 km of the northeastern coast of north island record episodic tectonic uplift a maximum of seven terraces are arranged in staircase fashion and lie about 20 km above the subduction interface between the pacific and australian plates the highest t1 corresponds with the maximum of the holocene marine transgression about 6700 14 c yr b p younger terraces are marine abrasion platforms overlain by thin beach deposits radiocarbon ages of marine shells from beach deposits indicate that uplift above marine conditions occurred ca 6700 t1 5500 t2 3900 t3 2500 4 1600 t5 1000 t6 and slightly younger than 600 t7 yr b p uplift probably occurred coseismically the maximum late holocene uplift rate in the study area is 8 mm yr altitudinal distribution of terraces suggests deformation exists as a ca 20 km elongate dome broken at the southern end by the pakarae fault which trends across the dome rupture on this fault has accompanied the growth of the dome but is not responsible for it bathymetric profiling suggests that an active fault parallel to and about 5 km offshore is probably responsible for the episodic coastal uplift

source rock characterization and oil generating potential of the jurassic madbi formation onshore east shabowah oilfields republic of yemen abstract the hydrocarbon source rock potential of shales from the jurassic madbi formation was evaluated using organic geochemistry rock eval pyrolysis toc and bitumen extraction and organic petrology very good source rock potential is suggested by high values of total organic carbon content toc 2 0 wt and high extractable organic matter content and hydrocarbon yields 11 000 and 6000 ppm respectively the madbi formation samples have high hydrogen index hi and low oxygen index oi values most of the samples in the study area are thermally mature and contain oil prone type i and type ii kerogen vitrinite reflectance ro values for the madbi shale samples were measured from 0 74 to 0 89 tmax values range from 430 to 438 c which are in reasonably good agreement with vitrinite reflectance data reveal that the madbi shales are at the early to peak mature stage on the basis of biomarker maturity parameters these shales are thermally mature shales of the madbi formation contain abundant hydrogen rich kerogen liptinite up to 55 and therefore good oil generating potential is anticipated this is supported by high hydrogen indices hi of up to 400 mg hc g toc and early to peak mature oil window range

biological markers and carbon isotope composition of organic matter in the upper cretaceous coals and carbonaceous shale succession jiza qamar basin yemen origin type and preservation abstract bituminous coals and carbonaceous shales located in the jiza qamar basin on the eastern yemen were analysed based on a combined investigation of organic geochemistry and petrology to define the palaeodepositional environment condition organic matter inputs and their thermal maturity carbon isotope compositions and various biomarkers were performed on coals and carbonaceous shales within the upper cretaceous mukalla formation in the jiza qamar basin the 13 c values range from 29 2 to 24 5 with average values around 26 7 whereas the organic carbon contents in most sediment samples are consistently high 3 indicating that the organic matter in the mukalla coal and carbonaceous shale sediments has a predominantly terrigenous origin with slightly marine influence during burial this has also been identified from kerogen microscopy which is characterized by dominance of vitrinite and liptinite organic matter the investigated biomarkers indicated that the mukalla coals and carbonaceous shales contain high contribution of land plants with a minor aquatic organic matter input that was deposited in a fluvial to deltaic environments and preserved under relatively oxic conditions this has been achieved from acyclic isoprenoids terpane and sterane biomarkers of a saturated hydrocarbon and dibenzothiophene alkylnaphthalene and methylphenanthrene biomarkers of an aromatic hydrocarbon based on the analysed biomarker thermal maturity indicators it may be deduced that the mukalla coals and carbonaceous shales in the jiza qamar basin have entered an early mature to mature stages for hydrocarbon generation this is also supported by vitrinite reflectance values of 0 63 0 83 ro indicative that these sediments have reached oil window maturity

late quaternary uplift rates of marine terraces on the pacific coast of north america southern oregon to baja california sur abstract marine terraces are common landforms along the pacific coast of north america from southern oregon to southern baja california we report 60 new uranium series ages of marine terrace corals hydrocorals and other fossils terraces representing the ca 80 ka and ca 125 ka high stands of sea are the most common along the pacific coast and we have used these ages along with terrace shoreline angle elevations and paleo sea level estimates to calculate late quaternary uplift rates uplift rates in the forearc region of the cascadia subduction zone range from 0 45 1 08 m kyr farther south along most of the coast west of the san andreas fault zone uplift rates range from 0 15 0 35 m kyr but some areas have significantly higher rates of uplift and others have apparently experienced little or no uplift in the last 125 ka in baja california sur west of the east pacific rise little or no uplift has occurred during the late quaternary on average the magnitude of rates of uplift for the tectonic regimes is as follows cascadia subduction zone san andreas fault zone region east pacific rise region

source rock characteristics and hydrocarbon generation modelling of upper cretaceous mukalla formation in the jiza qamar basin eastern yemen abstract the upper cretaceous mukalla coals and other organic rich sediments which are widely exposed in the jiza qamar basin and believed to be a major source rocks were analysed using organic geochemistry and petrology the total organic carbon toc contents of the mukalla source rocks range from 0 72 to 79 90 with an average toc value of 21 50 the coals and coaly shale sediments are relatively higher in organic richness consistent with source rocks generative potential the samples analysed have vitrinite reflectance in the range of 0 84 1 10 ro and pyrolysis t max in the range of 432 454 c indicate that the mukalla source rocks contain mature to late mature organic matter good oil generating potential is anticipated from the coals and coaly shale sediments with high hydrogen indices 250 449 mg hc g toc this is supported by their significant amounts of oil liptinite macerals are present in these coals and coaly shale sediments and py gc s 2 pyrograms with n alkane alkene doublets extending beyond nc 30 the shales are dominated by type iii kerogen hi one dimensional basin modelling was performed to analysis the hydrocarbon generation and expulsion history of the mukalla source rocks in the jiza qamar basin based on the reconstruction of the burial thermal maturity histories in order to improve our understanding of the of hydrocarbon generation potential of the mukalla source rocks calibration of the model with measured vitrinite reflectance ro and borehole temperature data indicates that the present day heat flow in the jiza qamar basin varies from 45 0 mw m 2 to 70 0 mw m 2 and the paleo heat flow increased from 80 ma to 25 ma reached a peak heat flow values of approximately 70 0 mw m 2 at 25 ma and then decreased exponentially from 25 ma to present day the peak paleo heat flow is explained by the gulf of aden and red sea tertiary rifting during oligocene middle miocene which has a considerable influence on the thermal maturity of the mukalla source rocks the source rocks of the mukalla formation are presently in a stage of oil and condensate generation with maturity from 0 50 to 1 10 ro oil generation 0 5 ro in the mukalla source rocks began from about 61 ma to 54 ma and the peak hydrocarbon generation 1 0 ro occurred approximately from 25 ma to 20 ma the modelled hydrocarbon expulsion evolution suggested that the timing of hydrocarbon expulsion from the mukalla source rocks began from 15 ma to present day

rock eval tmax suppression documentation and amelioration the rock eval thermal maturation parameter tmax may occasionally be suppressed relative to surrounding rock units this is commonly assumed to result from either a bitumen contribution to the s2 peak or the presence of sulfur rich and hence thermally labile kerogen the phenomenon is frequently coincident with a high natural gamma ray signature and elevated rock eval hydrogen index hi and total organic carbon toc contents determination of thermal maturity of such units relies either on the interpolation of tmax from surrounding units or the direct estimation of the extent of suppression on a given sample the latter may be required if the available samples are restricted to conventional or sidewall core material representative of imited stratigraphic intervals the second white speckled shale part of the cretaceous colorado group in the alberta basin displays tmax suppression over part of its thickness a consistent relationship emerges from calculating a linear regression of tmax as a function of either toc or hi for several wells at different levels of thermal maturity below values of about 453 c late oil window tmax is suppressed by about 1 c for every increase in hi of 50 mg hydrocarbon g toc thus tmax suppression in the second white speckled shale can be corrected by extrapolating all tmax values to a constant hi of 100 to 150 mg hydrocarbon g toc values typical of type iii kerogen

evidence of large prehistoric offshore earthquakes deduced from uplifted holocene marine terraces in pangasinan province luzon island philippines abstract uplifted holocene marine terraces in pangasinan province westernmost luzon island philippines are reported here for the first time as geomorphic evidence of large prehistoric offshore earthquakes we recognized up to three holocene terrace steps elevations of shoreline angles are ti 1 to 5 m tii 2 to 7 m and tiii 4 to 11 m above mean sea level amsl the lateral variation in the elevation of terrace steps indicates differential uplift along the coast the staircase topography characterized by horizontal abrasion platforms meter scale terrace risers and wave cut notches suggests that these geomorphic features were formed by large coseismic uplift events terrace morphology and radiocarbon ages further suggest that at least three coseismic coastal uplift events have occurred since the culmination of the post glacial sea level rise 6000 years ago we interpret tiii to be the holocene transgressive surface 6000 ybp and estimated a maximum uplift rate of 1 7 mm yr which is almost the same as the late pleistocene uplift rate of 1 3 mm yr we infer that proximity to offshore seismic sources has contributed to the deformation pattern of holocene terraces and variation in the number of terrace steps uplift patterns of marine terraces also suggest that the magnitude and location of prehistoric earthquakes may have varied between individual coseismic uplift events we conducted simple elastic dislocation modeling to evaluate the source parameters of the causative faults our preliminary models show that a landward dipping offshore reverse fault located at the base of a steep slope separating the fore arc basin and continental shelf could be responsible for coastal uplift along the western pangasinan peninsula

age height and deformation of holocene marine terraces at mahia peninsula hikurangi subduction margin new zealand mahia peninsula is a prominent coastal landmark in eastern north island and is the closest point of land in the north island to the hikurangi trough where the pacific plate plunges beneath the subduction complex at the eastern margin of the australian plate uplifted holocene marine deposits of both estuarine and open beach affinities are found in many parts of the peninsula and provide the basis for holocene tectonic characterization estuarine deposits record the later part of the postglacial transgression that culminated about 6500 years b p in new zealand the deposits have been differentially uplifted since that time at a rate of 2 5 0 3 mm yr in the central north coast area decreasing to 0 7 0 2 mm yr about 6 km to the west the coastal plain is characterised in many places by a stepped sequence of emergent shore platforms overlain by fossiliferous beach deposits extensive radiocarbon dating of samples from beach deposits shows that terraces in widespread parts of the peninsula are of five distinct ages each of the terraces is inferred to have formed in conjunction with a large prehistoric earthquake because of the stepped terrace morphology clustering of ages on each terrace differential uplift of terraces across the peninsula and historic coseismic uplift events in this tectonic setting paleoseismic events of mw 7 5 8 0 are estimated to have occurred approximately 250 1600 1900 3500 and 4500 years b p uplift distribution of the holocene and late pleistocene marine terraces shows that the peninsula lies on the west gentle flank of the active lachlan anticline which is cored by a major west dipping reverse fault the lachlan fault holocene active deformation at mahia peninsula and other coastal areas of eastern north island is a continuation of structures developed in pleistocene time in the landward part of the subduction complex adjacent to the hikurangi subduction zone

variations in the geochemistry of closely interbedded oil prone coals and shales paralic and deltaic environments frequently contain closely interbedded oil prone coals and carbonaceous shales of similar organic facies however differences in depositional and diagenetic conditions can result in significant variations in geochemistry between these coals and shales these variations are observed in sediments from a range of ages and areas including australia new zealand and indonesia for example pristane phytane and pristane n c sub 17 ratios are frequently higher in coals than in associated shales although n alkane distributions are similar the c sub 27 ts tm ratios are frequently much lower in coals although most other biomarker ratios are generally the same for coals and shales however absolute biomarker concentrations particularly of c sub 27 tm hopane can be two to four times higher in coals significantly many coals contain high concentrations of diasteranes equivalent to those observed in shales differences in other parameters such as the c sub 30 diahopane c sub 30 hopane ratios and pyrolysate compositions are also evident data indicate that rocks begin to become more coal like at tocs of approximately 25 the variations in these parameters are probably the result of variability in early depositional and diagenetic conditions such as eh ph and microbial action in addition these parameters are probably influenced by the effectsmore of an organic vs an inorganic matrix the impact of this variability must be considered when conducting oil source correlation studies and when assessing the relative contributions of coals and shales to the generation of oil in a basin less

organic geochemical characteristics and depositional environments of the jurassic coals in the eastern taurus of southern turkey abstract in this study organic matter content type and maturity as well as some petrographic and physical characteristics of the jurassic coals exposed in the eastern taurus were investigated and their depositional environments were interpreted the total organic carbon toc contents of coals in the feke akkaya kozan gedikli and kozan kizilinc areas are 24 54 66 78 and 49 15 respectively the feke akkaya and kozan kizilinc coals have low hydrogen index hi values while the kozan gedikli coals show moderate hi values all coal samples display very low oxygen index oi values the kozan gedikli coals contain type ii organic matter om the feke akkaya coals contain a mixture of type ii and type iii om and the kozan kizilinc coals are composed of type iii om sterane distribution was calculated as c27 c29 c28 from the m z 217 mass chromatogram for all coal samples tmax values for the feke akkaya kozan gedikli and kozan kizilinc coals are 439 412 and 427 c vitrinite reflectance values ro for the feke akkaya and kozan kizilinc coal samples were measured as 0 65 and 0 51 and these values reveal that the feke akkaya and kozan kizilinc coals are at subbituminous a or high volatile c bituminous coal stage on the basis of biomarker maturity parameters these coals have a low maturity the pristane phytane pr ph ratios for the feke akkaya kozan gedikli and kozan kizilinc coals are 1 53 1 13 and 1 25 respectively in addition all coals show a homohopane distribution which is dominated by low carbon numbers and c35 homohopane index is very low for all coal samples all these features may indicate that these coals were deposited in a suboxic environment the high sterane hopane ratios with high concentrations of steranes low pr ph ratios and c25 c26 tricyclic ratios 1 may indicate that these coals formed in a swamp environment were temporarily influenced by marine conditions

organic geochemical characteristics and depositional environment of the tertiary tanjong formation coals in the pinangah area onshore sabah malaysia article i nfo article history the tertiary tanjong formation coals exposed in the west middle block of the pinangah coalfield central part of southern sabah were analyzed and their depositional environments were interpreted the tertiary tanjong coals are humic and generally dominated by vitrinite with significant amounts of liptinite and low amounts of inertinite macerals total organic carbon contents toc of the coals range from 51 2 to 77 7 wt and yield of bitumen values ranging from 57 300 to 140 000 ppm which meet the standard as a source rock with good hydrocarbon generative potential in support good liquid hydrocarbons generation potential can be expected from the tanjong coals based on significant liptinitic content 15 this is supported by their high hydrogen index up to 300 mg hc g toc consistent with type ii and mixed type ii iii kerogens and py gc s2 pyrograms with n alkane alkene doublets extending beyond c30 the coal samples have vitrinite reflectance values in the range of 0 42 0 66 ro indicating immature to early mature stage for hydrocarbon generation these vitrinite reflectance values also indicated that the tanjong coals are with sub bituminous b a and high volatile bituminous c rank tmax values ranging from 419 to 451 c are good agreement with the vitrinite reflectance data this is supported by biomarker maturity parameters as suggested by the c32 homohopane the saturated fraction of the tanjong coals are characterized by dominant odd carbon numbered n alkanes n c23 to n c33 high pr ph ratios 8 18 high tm ts ratios 6 28 and pre dominant of regular sterane c29 all biomarker parameters clearly indicate that the organic matter was de rived from terrestrial inputs and deposited under oxic condition

generation and expulsion of oils from permian coals of the sydney basin australia abstract organic geochemical and petrological assessment of coals coaly shales and fine grained sediments coupled with organic geochemical analyses of oil samples all from permo triassic sections of the southern sydney basin australia have enabled identification of the source for the widely distributed oil shows and oil seeps in this region the permian coals have higher hydrogen indices higher liptinite contents and much higher total organic matter extract yields than the fine grained sediments a variety of source specific parameters obtained from n alkanes regular isoprenoids terpanes steranes and diasteranes indicate that the oil shows and seeps were generated and expelled predominantly from higher plant derived organic matter deposited in oxic environments the source and maturity related biomarkers and aromatic hydrocarbon distributions of the oils are similar to those of the coals the oil coal relationship also is demonstrated by similarities in the carbon isotopic composition of the total oils coal extracts and their individual n alkanes extracts from the permo triassic fine grained sediments on the other hand have organic geochemical signatures indicative of mixed terrestrial and prokaryotic organic matter deposited in suboxic environments which are significantly different from both the oils and coal extracts the molecular signatures indicating the presence of prokaryotic organic matter in some of the coal extracts and oils may be due to thin sections of possibly calcareous lithologies interbedded within the coal measures the genetic relationship between the oils and coals provides new evidence for the generation and expulsion of oils from the permian coals and raises the possibility for commercial oil accumulations in the permian and early triassic sandstones potentially in the deeper offshore part of the sydney basin

non volcanic tremor associated with the march 2010 gisborne slow slip event at the hikurangi subduction margin new zealand 1 non volcanic tremor accompanies slow slip events at most circum pacific subduction zones previously the hikurangi subduction margin new zealand and the boso peninsula of japan have been noted as exceptions where slow slip which occurs at shallow depth compared to other subduction zones does not generate seismic tremor the lack of tremor observations raises questions whether tremor and slow slip are manifestations of the same process and whether different temperature and pressure conditions influence the physical mechanism of tremor production analysis of seismic data during the march 2010 gisborne slow slip event new zealand reveals that this slow slip event at the northern hikurangi margin is accompanied by tremor with distinctive characteristics compared to local microearthquakes both the gisborne area of new zealand and the boso peninsula of japan are underlain by thick accumulations of sedimentary rocks that likely inhibit the observation of low amplitude tremor due to high attenuation discovery of tremor in new zealand suggests that tremor may always accompany slow slip and that its apparent absence at the boso peninsula the hikurangi margin prior to this study and any future regions discovered to experience slow slip without concurrent tremor may be the effect of highly attenuating sediments

a late holocene marine terrace on the kidnappers coast north island new zealand some implications for shore platform development processes and uplift mechanism abstract a marine terrace up to 6 m above present mean sea level is preserved along 15 km of the kidnappers coast hawke s bay north island new zealand radiocarbon dates for 10 shell samples collected from intertidal marine deposits overlying an uplifted shore platform have a total age range of 590 yr from 2280 50 to 2750 70 yr b p sample age decreases landward suggesting a small relative sea level rise probably as a result of tectonic subsidence prior to uplift rates of contemporary shore platform formation preclude the preservation of a marine terrace subjected to constant aseismic uplift preservation of a subhorizontal uplifted shore platform mantled by intertidal marine deposits with in situ fauna is best explained by abrupt coseismic uplift 2300 yr b p and preceded by tectonic subsidence the presence of a single marine terrace does not permit the calculation of past earthquake magnitude or recurrence but the nne tilt of the 2300 yr old marine terrace indicates continued growth of the north trending late pleistocene kidnappers anticline

submarine paleoseismology of the northern hikurangi subduction margin of new zealand as deduced from turbidite record since 16 ka abstract paleoseismic studies seek to characterise the signature of pre historical earthquakes by deriving quantitative information from the geological record such as the source magnitude and recurrence of moderate to large earthquakes in this study we provide a 16 000 yr long paleo earthquake record of the 200 km long northern hikurangi margin new zealand using cm thick deep sea turbidites identified in sediment cores cores were collected in strategic locations across the margin within three distinct morphological re entrants the poverty ruatoria and matakaoa re entrants the turbidite facies vary from muddy to sandy with evidence for rare hyperpycnites interbedded with hemipelagites and tephra we use the oxal probabilistic software to model the age of each turbidite using the sedimentation rate of hemipelagite deduced from well dated tephra layers and radiocarbon ages measurements on planktonic foraminifera turbidites are correlated from one core to the other using similarity in sedimentary facies petrophysical properties and ages results show that 46 turbidites are synchronous along the entire margin amongst them 41 are interpreted as originating from the upper continental slope in response to earthquake triggered slope failures between 390 170 to 16 450 310 yr bp using well established empirical relationships that combine peak ground acceleration magnitude and location of earthquakes we calculate that synchronous slope failures were triggered by the rupture of 3 of the 26 known active faults in the region each capable of generating mw 7 3 to 8 4 earthquakes two are crustal reverse faults and one is the subduction interface the 41 mw 7 3 earthquakes occurred at an average recurrence interval of 400 yr over the last 16 000 yr among them twenty are interpreted as subduction interface earthquakes that occurred at an average recurrence interval of 800 yr with alternating periods of high activity and low return times 305 610 yr and quiescence periods with high return times 1480 2650 yr based on turbidite paleoseismology we propose that subduction interface earthquakes were of lower magnitude during active periods mw 7 5 than during quiescence periods mw 8 2

using uplifted holocene beach berms for paleoseismic analysis on the santa maria island south central chile major earthquakes m 8 have repeatedly ruptured the nazca south america plate interface of south central chile involving meter scale land level changes earthquake recurrence intervals however extending beyond limited historical records are virtually unknown but would provide crucial data on the tectonic behavior of forearcs we analyzed the spatiotemporal pattern of holocene earthquakes on santa maria island smi 37 degrees s located 20 km off the chilean coast and approximately 70 km east of the trench smi hosts a minimum of 21 uplifted beach berms of which a subset were dated to calculate a mean uplift rate of 2 3 0 2 m ky and a tilting rate of 0 022 0 002 degrees ky the inferred recurrence interval of strandline forming earthquakes is similar to 180 years combining coseismic uplift and aseismic subsidence during an earthquake cycle the net gain in strandline elevation in this environment is similar to 0 4 m per event

a holocene incised valley infill sequence developed on a tectonically active coast pakarae river new zealand abstract a sequence of fluvio estuarine sediments exposed beneath the highest holocene marine terrace at pakarae north island new zealand records the early mid holocene infilling of the pakarae valley this sequence was developed on an active coseismically uplifting coastline and provides a valuable comparison to widely used facies models for estuaries which were developed exclusively from stable coastal settings we describe eight sedimentary sections distributed along a 220 m stretch of riverbank and present twelve new radiocarbon ages sedimentology and benthic foraminifera are used to divide the sequence into eight bio lithofacies these units are grouped into four paleoenvironmental facies associations barrier estuarine estuary head delta and floodplain we compare the distribution of the pakarae paleoenvironmental facies associations to those in models of incised valley infill sequence models and case studies of infilled valleys these data allow us to present new contributions to the development of a facies model for the sedimentary infilling of an incised valley system that was experiencing coseismic uplift synchronous with deposition we suggest the distinctive characteristics of such a model would include 1 part or all of the transgressive and lowstand sequences may now lie above modern sea level 2 the transgressive sedimentary sequence is typically condensed relative to the coeval amount of eustatic sea level sl rise that occurred during that period and 3 evidence of relative sl falls such as transitions from estuarine to fluvial environments despite conditions of rapid and continuous eustatic sl rise

hydrocarbon potential of pennsylvanian coal in bohai gulf basin eastern china as revealed by hydrous pyrolysis abstract a hydrous pyrolysis experiment was performed using pennsylvanian brown coal with a vitrinite reflectance vr 0 of 0 56 from a coal mine at the southwest corner of the bohai gulf basin eastern china to evaluate the hydrocarbon potential of the coal the coal sample is vitrinite rich 74 5 and inertinite poor 16 7 with liptinite content of 8 8 much of the vitrinite in the sample consists of hydrogen rich vitrinite collodetrinite hydrous pyrolysis was performed at 200 c 230 c 260 c 290 c 320 c and 350 c for 72 h separately yields of both total liquid pyrolysates and expelled oil increased with temperature before reaching their maximum production of 17 27 kg t coal and 14 57 kg t coal at the same temperature of 320 c vr 0 1 18 and decreased afterwards gaseous products increased sharply at 320 c and tended to increase even at the highest experimental temperature 350 c vr 0 1 53 results show that the coal has not only a certain oil generation potential but also a large capacity for gas production and a high expulsion efficiency oil potential of the coal is attributed to its depositional environment which was transitional from shallow marine to coastal plain or swamp during middle to late pennsylvanian the coal was protected from oxidation under water after deposition experimental results indicate that this pennsylvanian coal could have contributed to oil gas accumulation in the bohai gulf basin

significance of coniferous rain forests and related organic matter in generating commercial quantities of oil gippsland basin australia contrary to the conventional belief that humic coal generates primarily gas 3 billion bbl of recoverable oil has been discovered in the humic coaly succession of the fluviodeltaic latrobe group upper cretaceous tertiary that serves as both the reservoir and the source for hydrocarbons in the offshore gippsland basin of southeastern australia evidence for generation of liquid hydrocarbons from the coaly succession includes 1 similarity of n alkane distribution in the oil and in the coal extracts 2 high wax content of oil up to 27 by weight 3 high ratio of pristane phytane in oil 5 6 and 4 dominance of c29 steranes in the oil in the gippsland basin coniferous rain forests dominated by kauri vegetation flourished in a raised bog setting present temperate climate and kauri vegetation of new zealand are considered to be the modern analog to the gippsland basin the coniferous vegetation provided large quantities of hydrogen rich exinite macerals such as cutinite and resinite with potential to generate oil high rainfall raised ground water level low oxygen high acidity and low nutrient conditions of a raised bog setting were suitable for preserving organic matter a comparison of gas chromatograms of oils in the gippsland basin with gas chromatograms of oils generated by hydrous pyrolysis in the laboratory from the immature source rocks suggests that the paraffinic fraction of the oil was derived from coal and the naphthenic fraction was derived chiefly from resin

complex rupture during the 12 january 2010 haiti earthquake initially the devastating mw 7 0 12 january 2010 haiti earthquake seemed to involve straightforward accommodation of oblique relative motion between the caribbean and north american plates along the enriquillo plantain garden fault zone here we combine seismological observations geologic field data and space geodetic measurements to show that instead the rupture process involved slip on multiple faults primary surface deformation was driven by rupture on blind thrust faults with only minor deep lateral slip along or near the main enriquillo plantain garden fault zone thus the event only partially relieved centuries of accumulated left lateral strain on a small part of the plate boundary system together with the predominance of shallow off fault thrusting the lack of surface deformation implies that remaining shallow shear strain will be released in future surface rupturing earthquakes on the enriquillo plantain garden fault zone as occurred in inferred holocene and probable historic events we suggest that the geological signature of this earthquake broad warping and coastal deformation rather than surface rupture along the main fault zone will not be easily recognized by standard palaeoseismic studies we conclude that similarly complex earthquakes in tectonic environments that accommodate both translation and convergence such as the san andreas fault through the transverse ranges of california may be missing from the prehistoric earthquake record

oil generating potential of tertiary coals and other organic rich sediments of the nyalau formation onshore sarawak the oil generating potential of coals and other organic rich sediments from the late oligocene early miocene nyalau formation the offshore extension of which is believed to be a major source rock is evaluated coals of the nyalau formation are typically dominated by vitrinite with moderate and low amounts of exinite and inertinite respectively significant amounts of clay minerals are present in these coals and those containing between 15 to 65 mineral matter by volume are termed carbargilite the samples analysed range from sub bituminous to high volatile bituminous rank possessing vitrinite reflectance in the range 0 42 to 0 72 tmax values range from 425 450 c which is in good agreement with vitrinite reflectance data good oil generating potential is anticipated from these coals and carbargilites with moderate to rich exinite content 15 35 this is supported by their high hydrogen indices of up to 400 mghc gtoc py gc s2 pyrograms with n alkane alkene doublets extending beyond nc30 and their being in the early to mid mature oil window range petrographically the most significant evidence of the oil generating potential of these coals is the generation of petroleum like materials exsudatinite visible under the microscope exsudatinite is a secondary maceral commonly considered to represent the very beginning of oil generation in coal which is shown here to also have an important role to play in hydrocarbon expulsion the precursor of exsudatinite in these coals is the maceral bituminite which readily expels or mobilizes to hydrocarbon like material in the form of oil smears and or exsudatinite as observed under the microscope the maceral bituminite is considered to play a major generative role via early exsudatinite generation which is considered to facilitate the overall expulsion process in coaly source rocks

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

slow slip on the northern hikurangi subduction interface new zealand 1 in october 2002 a surface displacement episode of 20 30 mm magnitude was observed over a 10 day period on two continuous global positioning system gps instruments near gisborne north island new zealand we interpret this to result from slow slip on the northern hikurangi subduction interface using ten years of regional campaign gps 1995 2004 and recent continuous gps data we estimate the recurrence interval for similar events to be 2 3 yrs in november 2004 a similar slow slip event occurred within this recurrence period the 2002 event can be modeled by 18 cm of slow slip near the down dip end of the seismogenic zone on the subduction interface offshore of gisborne the campaign gps data show that the 2002 slow slip event had little effect on regional strain patterns

a proposed laramide proto grand canyon abstract the absence of rim gravels north of grand canyon and of canaan peak type gravels south of grand canyon suggests that a paleocanyon which intersected the transport of these gravels north and south may have begun forming in the laramide in approximately the same position as today s central grand canyon this laramide age canyon is envisioned as having flowed generally from the sw to ne from the peach springs canyon area to mile 197 where it was captured by karst then along a n 60 e joint system to the kanab point area where it converged with drainage coming off the west side of the kaibab arch from there it flowed north along the west flank of the kaibab arch to paleogene lake claron the critical idea suggested by this proposed model is that the modern colorado river utilized laramide paleotopography in establishing its course through the central grand canyon with younger sections of the canyon integrating with it later in the middle to late miocene this paleocanyon route in association with headward erosion from the grand wash cliffs toward the kaibab arch after 16 17 ma helps account for the total volume of rock eroded from grand canyon which cannot be explained by present day incision rates

coastal staircase sequences reflecting sea level oscillations and tectonic uplift during the quaternary and neogene many coasts feature sequences of quaternary and neogene shorelines that are shaped by a combination of sea level oscillations and tectonics we compiled a global synthesis of sea level changes for the following highstands mis 1 mis 3 mis 5e and mis 11 also we date the apparent onset of sequences of paleoshorelines either from published data or tentatively extrapolating an age for the uppermost purported oldest shoreline in each sequence including the most documented mis 5e benchmark we identify 926 sequences out of which 185 also feature holocene shorelines six areas are identified where elevations of the mis 3 shorelines are known and 31 feature elevation data for mis 11 shorelines genetic relationships to regional geodynamics are further explored based on the elevations of the mis 5e benchmark mean apparent uplift rates range from 0 01 0 01 mm yr hotspots to 1 47 0 08 mm yr continental collision passive margins appear as ubiquitously uplifting while tectonic segmentation is more important on active margins from the literature and our extrapolations we infer ages for the onset of formation for 180 coastal sequences sea level fingerprinting on coastal sequences started at least during mid miocene and locally as early as eocene whether due to the changes in the bulk volume of seawater or to the temporal variations in the shape of ocean basins estimates of eustasy fail to explain the magnitude of the apparent sea level drop thus vertical ground motion is invoked and we interpret the long lasting development of those paleoshore sequences as the imprint of glacial cycles on globally uplifted margins in response to continental compression the geomorphological expression of the sequences matches the amplitude and frequency of glacial cyclicity from middle pleistocene to present day moderately fast 100 000 yrs oscillating sea levels favor the development of well identified strandlines that are distinct from one another pliocene and lower pleistocene strandlines associated with faster cyclicity 40 000 yrs are more compact and easily merge into rasas whereas older cenozoic low frequency eustatic changes generally led to widespread flat lying coastal plains

organic geochemical and petrographic characteristics of neogene organic rich sediments from the onshore west baram delta province sarawak basin implications for source rocks and hydrocarbon generation potential abstract the neogene succession of the onshore petroleum prolific west baram province of north west borneo contains organic rich sediments particularly within sarawak basin bulk and quantitative pyrolysis results coupled with organic petrographic characteristics of neogene organic rich sediments have enabled investigation of the source rock characteristics and evaluation of the hydrocarbon generation potential the results were used to assess the quantity of organic matter kerogen composition thermal maturity and type of petroleum that could possibly be generated from these neogene sediments the total organic carbon toc contents of the neogene sediments range between 1 06 and 11 11 wt and hydrogen index hi values are largely below 105 mg hc g toc suggesting that the sediments are organically rich and contain gas prone type iii kerogen this kerogen type is supported by the abundant terrestrial materials i e vitrinite phytoclasts spores and pollen low atomic hydrogen to carbon atomic h c ratio and high abundance of aromatic hydrocarbons in pyrolysis gc pyrograms and would likely generate mainly condensate and gas the analysed samples have vitrinite reflectance in the range of 0 39 0 48 ro and pyrolysis t max in the range of 401 434 c which indicate that these neogene sediments contain immature to very early mature organic matter this implies that these onshore sediments have not been buried to a sufficient depth however the offshore stratigraphic equivalent of these sediments are known to have been buried to deeper depth and could therefore act as an effective petroleum source rock in particular for natural gas

hydrocarbon distribution in coals and in dispersed organic matter of different maceral compositions and maturities more than 60 samples from 5 coal seams and adjacent siltstones and sandstones were selected from a well through westphalian b sediments from northern germany in order to study bitumen generation and migration the cores were drilled between 1200 und 1530 metres depth in this interval vitrinite reflectance rr is increasing from 0 70 to 0 92 results reveal high hydrocarbon generation potentials for all coal samples but not for adjacent clastic rocks although maceral compositions of both are quite similar yields and compositions of thermal extracts from the coals depend on maceral compositions and rank however the bulk of the already generated bitumen has not been removed during natural coalification and is not easily releasable by thermovaporisation a mass balance based on elemental composition of dull coals indicates that in the rather narrow rank interval 0 70 0 92 rr a total mass loss of 20 may have occurred by migration this is evidenced by a loss of about 20 of the original hydrogen the rest being stored in the coals

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

the mendocino triple junction active faults episodic coastal emergence and rapid uplift a complex zone of rapid holocene surface uplift and deformation occurs at the mendocino triple junction the juncture of three plate bounding faults the cascadia subduction zone san andreas fault and mendocino fault within this mountainous structural knot up to 1 4 m of coastal emergence occurred during the 1992 cape mendocino m s 7 1 earthquake surveying and radiometric dating of ancient marine strandlines 7 5 along the cascadia subduction zone megathrust however another plausible interpretation of the data is that multiple earthquakes resulting in smaller amounts of net surface uplift per event similar to the 1992 earthquake occurred closely spaced in time giving the appearance in the geologic record of less frequent and larger events regardless of the number and timing of paleoearthquakes the number of platforms is a minimum of the number of events that resulted in sudden rapid uplift because platform preservation is also a function of rising holocene sea level at present rates and patterns of net surface uplift are better constrained than the timing and magnitude of paleoearthquakes periods of rapid holocene emergence also are identified as far south of the area of 1992 uplift and the mendocino fault as 30 km along the unlocated san andreas fault these also might be associated with coseismic uplift based on new mapping of active faults in the region it is proposed here that this uplift is the result of multiple discontinuous thrust and strike slip fault segments which distribute plate boundary deformation along a restraining bend at the termination of the san andreas fault this interpretation is consistent with the fact that a single prominent strike slip fault has not been identified in the mendocino triple junction region while several small reverse faults crossing holocene deposits and geomorphic surfaces have been mapped and dated

organic geochemical and petrographic characteristics of tertiary coals in the northwest sarawak malaysia implications for palaeoenvironmental conditions and hydrocarbon generation potential abstract tertiary coals from mukah and balingian coalfields in the northwest sarawak malaysia were investigated to evaluate their regional rank variation petroleum generative potential and to reconstruct the palaeoenvironment conditions during peat accumulation the tertiary coals are characterized by high total organic carbon contents toc and yield of bitumen extraction ranging from 31 3 to 55 9 wt and 25 724 9 92 143 7 ppm respectively meet the standard as a good source rock potential the mukah and balingian coals were generally plotted in an area of type iii kerogen and mixed type ii iii kerogens with hi values between 90 and 289 mg hc g toc whereby the coals were derived from plant materials of terrigenous origin this shows that the balingian coals are dominated by type iii terrigenous kerogen while mukah coals are dominated by type ii iii kerogens and are thus considered to be generate mainly gas prone and limited oil prone this is also supported by macerals composition and open system pyrolysis gas chromatography py gc the mukah and balingian coals are thermally immature in rang from lignite to sub bituminous c rank possessing huminite reflectance in the range of 0 26 0 39 this immaturity has a considerable influence on the proximate analysis particularly on relatively high moisture and volatile matter contents and relatively low fixed carbon content petrographically it was observed that the mukah and balingian coals are dominated by huminite with low to high amounts of liptinite and relatively low amounts of inertinite pointing to predominantly anaerobic deposition conditions in the paleomires with limited thermal and oxidative tissue destruction the palaeoenvironment conditions of the coals are generally interpreted as a lower deltaic plain wet peat swamp depositional setting which are generally characterised by low tpi and high gi values and are plotted on the marsh field of the diessel s diagram this is usually consistent with generate relatively high ash yield as is the case of the mukah and balingian coals

holocene paleoseismicity in the fold and thrust belt of the hikurangi subduction zone eastern north island new zealand abstract along the 500 km long eastern coastline of the north island new zealand there are at most seven distinct holocene marine terraces aged 7 ka b p or less the highest of the terraces is 27 m above present day mean sea level the coastal region is subdivided into fourteen distinct subregions based on radiocarbon ages of marine deposits overlying wave cut shore platforms and geographic distribution of similarly aged terraces holocene marine terraces are the result of uplift associated with large earthquakes co seismic deformation this conclusion is based on characteristic stepped terrace morphology clustering of ages of terrace deposits within subrogions and the occurrence of co seismic uplift in historic time differential uplift across structures and distinct age variations at subregion boundaries are also characteristic recurrence intervals of uplift in any one terrace sequence vary from 0 4 ka to 2 0 ka and individual amounts of uplift vary from 1 0 m to 4 0 m in the past 2 5 ka ages from all terraces within subrogions indicate at least 21 paleoseismic events affecting coastal areas of eastern north island in that period these events cluster in time and in separate parts of eastern north island several earthquakes occurred 0 3 0 6 1 0 1 5 2 1 and 2 3 ka b p our data strongly support the concept of segmentation of deformation along the subduction margin the likely cause of coastal uplift is movement on steep reverse faults local structures rather than the subduction thrust that propagate from or near the subduction thrust some 20 25 km below the region earthquakes of moment magnitude 7 3 8 0 are estimated to be associated with these fault movements

early holocene paleoseismic history at the pakarae locality eastern north island new zealand inferred from transgressive marine sequence architecture 1 early holocene transgressive marine deposits infilling the pakarae river paleovalley are used to extend the paleoseismic history of the pakarae river locality east coast north island new zealand back in time prior to eustatic sea level stabilization at 7 calibrated cal ka b p paleoenvironmental evolution of the pakarae river paleovalley from 7 to 10 cal ka b p is reconstructed using sedimentology and biostratigraphy two estuarine units display sudden vertical transitions to floodplain sediments implying significant marine regressions and estuary abandonment these regressions are attributed to coseismic coastal uplift events at 9000 and 8500 cal years b p a third uplift between 8500 and 7350 cal years b p is inferred from a significant difference between the amount of sediment preserved and the predicted sediment thickness according to the eustatic sea level curve this study demonstrates the utility of the analysis of transgressive deposits and their paleoenvironmental characteristics for neotectonic investigations on active coasts

holocene coastal evolution and uplift mechanisms of the northeastern raukumara peninsula north island new zealand abstract the coastal geomorphology of the northeastern raukumara peninsula new zealand is examined with the aim of determining the mechanisms of holocene coastal uplift elevation and coverbed stratigraphic data from previously interpreted coseismic marine terraces at horoera and waipapa indicate that despite the surface morphology there is no evidence that these terraces are of marine or coseismic origin early holocene transgressive marine deposits at hicks bay indicate significant differences between the thickness of preserved intertidal infill sediments and the amount of space created by eustatic sea level rise therefore uplift did occur during early holocene evolution of the estuary the palaeoecology and stratigraphy of the sequence shows no evidence of sudden land elevation changes beach ridge sequences at te araroa slope gradually toward the present day coast with no evidence of coseismic steps the evolution of the beach ridges was probably controlled by sediment supply in the context of a background continuous uplift rate no individual dataset uniquely resolves the uplift mechanism however from the integration of all evidence we conclude that holocene coastal uplift of this region has been driven by a gradual aseismic mechanism an important implication of this is that tectonic uplift mechanisms do vary along the east coast of the north island this contrasts with conclusions of previous studies which have inferred holocene coastal uplift along the length of the margin was achieved by coseismic events this is the first global example of aseismic processes accommodating uplift at rates of 1 mm yr 1 adjacent to a subduction zone and it provides a valuable comparison to subduction zones dominated by great earthquakes

holocene evolution of an estuary on a tectonically rising coast the pakarae river locality eastern north island new zealand abstract estuarine and beach deposits in the vicinity of the present coastline at pakarae river record the infilling of an estuary and subsequent development of a sequence of seven marine terraces during holocene time at the maximum of the last glaciation about 18 000 years ago the shoreline at the ancestral pakarae river was approximately 20 km east of the present shoreline by about 9000 years bp the sea had transgressed across most of that coastal plain to lie within a few hundred metres of the base of the present coastal hills seventeen radiocarbon ages from estuarine deposits record the overall rise in post glacial sea level but in the period c 9500 7000 yrs bp there are reversals to the overall rising trend between 9500 and 8500 yrs bp there appears to have been a eustatic fall in sea level of at least 4 m this observation is supported by data from several other localities around new zealand maximum transgression occurred about 6500 7000 yrs bp when the sea reached the base of hillslopes and an extensive estuary existed behind a barrier bar since that time the barrier bar disappeared probably due to stranding in an uplift event and the coastline advanced progressively outward toward its present position coastal progradation sea level regression and subsequent erosion have occurred in association with episodic large earthquakes at about 6700 5400 3910 2450 1570 1000 and 600 yrs bp the present distribution of terraces has been influenced by coastal erosion which has removed all trace of some terraces from some areas and river erosion has modified the marine terraces near the river

an examination of spatial variability in the timing and magnitude of holocene relative sea level changes in the new zealand archipelago holocene relative sea level rsl changes have been reconstructed for four regions within the new zealand archipelago the northern north island including northland auckland and the coromandel peninsula the southwest coast of the north island the canterbury coast south island and the otago coast south island in the north island the rsl highstand commenced c 8100 7240 cal yr bp when present mean sea level pmsl was first attained this is c 600 1400 years earlier than has been previously indicated for the new zealand region as a whole and is consistent with recent holocene rsl reconstructions from australia in north island locations the early holocene sea level highstand was quite pronounced with rsl up to 2 75 m higher than present in the south island the onset of highstand conditions was later with the first attainment of pmsl being between 7000 6400 cal yr bp in the mid holocene the northern north island experienced the largest sea level highstand with rsl up to 3 00 m higher than present this is demonstrably higher than the highstand recorded for the southwest north island and otago regions a number of different drivers operating at a range of scales may be responsible for the spatial and temporal variation in the timing and magnitude of rsl changes within the new zealand archipelago one possible mechanism is the north south gradient in rsl that would arise in the intermediate field around antarctica in response to the reduced gravitational attraction of the antarctic ice sheet ais as it lost mass during the holocene this gradient would be enhanced by the predicted deformation of the lithosphere in the intermediate field of the southern ocean around antarctica due to hydro isostatic loading and mass loss of the ais however no such long wavelength signals in sea surface height or solid earth deformation are evident in glacial isostatic adjustment gia model predictions for the new zealand region while research from australia has suggested that north south variations in holocene rsl changes due to hydro isostatic influences are limited or non existent at the regional to local scale post glacial meltwater loading on the continental shelf around new zealand is predicted by gia modelling to have a significant effect on the timing and magnitude of rsl changes through the phenomenon of continental levering the spatial variation in continental levering is controlled by the configuration of the coast and the width of the adjacent continental shelf with continental levering providing a robust explanation for the observed spatial and temporal variations in rsl changes further research is required to characterise the regional and local effects of different tectonic regimes wave climates and sediment regimes these are potentially very significant drivers of rsl variability at the regional to local scale however the magnitude of their potential effects remains equivocal

pristane phytane ratios in the mineralized kupferschiefer of the fore sudetic monocline southwest poland abstract the interaction of organic matter with fluids is important in geochemical processes in surface and diagenetic environments in the kupferschiefer copper deposits of southwestern poland organic fluid interactions are inferred to have been important in the genesis of the ore deposits previous organic geochemical studies of the kupferschiefer report evidence of a late diagenetic oxidation event that altered the organic geochemistry this study uses the saturated hydrocarbons as indicators of the biological input and the earliest diagenetic processes to affect the organic geochemistry of the kupferschiefer the normal alkane distributions are lithofacies controlled indicating that they reflect biological input the ratio of the saturated isoprenoids pristane phytane are potential indicators of the redox conditions during sedimentation and diagenesis very low pr ph ratios are associated with lithofacies that were deposited in hypersaline environments increases in the pr ph ratio within individual traverses are interpreted as indicating increasing oxidation of organic matter during deposition and early diagenesis trends of increasing pristane phytane ratios are observed at the base of the kupferschiefer and at the transition within the kupferschiefer from the clay rich to the carbonate rich kupferschiefer which corresponds approximately to the transition from cu zone to the pb zone early diagenetic copper depleted cu and cu fe sulfides have also been reported form the top of the weissliegendes and the cu zone pb zone transition and it is conceivable that both could be related to the same processes

correlation of different maturity parameters in the ahmedabad mehsana block of the cambay basin abstract the potential use of organic matter maturation parameters in assessing the diagenetic catagenetic transition zone with the help of various known molecular parameters has been investigated in the ahmedabad mehsana block of the cambay basin a set of 24 conventional cores from the eocene shales covering a depth regime of 922 2500 m has been studied the oil generation threshold i e the boundary between the diagenetic and catagenetic maturation regimes is assessed to be at 1800 m based on a combination of parameters including percent hydrocarbons in eom saturate aromatic hydrocarbon ratio in eom and the rock eval production index the pr n c17 ratio rock eval hi and oi were not suitable for reliable maturation profiling nor for independently indexing the stages of maturation the extent of the catagenetic regime is distinguished by ph n c18 ratios

measurement of tectonic surface uplift rate in a young collisional mountain belt measurement of the rate of tectonically driven surface uplift is crucial to a complete understanding of mountain building dynamics the lack of a suitable rock record typically prevents determination of this quantity but the unusual geology of papua new guinea s finisterre mountains makes measurement of this rate possible the tectonic surface uplift rate at the finisterre range is 0 8 2 1 mmyr 1 approximately that expected to arise from crustal thickening

sensitivity of biomarker properties to depositional environment and or source input in the lower toarcian of sw germany abstract a sequence of lower toarcian sediments which are highly contrasting in their depositional environment over a 5 m depth interval has been investigated in detail for the variability of geochemical properties which are used for source characterization and oil to source correlation lower liassic marls are representative of a well aerated shallow water environment in contrast to the immediately overlying bituminous shales which are deposited under extremely reducing conditions various properties have been found to vary considerably within these two units amongst the most important are carbon isotopic composition of the kerogen the pristane phytane ratios nickel as opposed to vanadyl porphyrins and the c27 dia regular steranes although maturation within the profile does not change some of the maturation dependent biomarker properties such as the monoaromatic steroid side chain cracking and the tm ts ratio exhibit large changes which can be assigned to diagenetic processes another maturation dependent property the 20s 20r epimerization of c29 steranes exhibits smaller changes which could also be due to early diagenetic processes the study suggests that reducing and oxidizing conditions i e eh and ph in the sediment exert an influence on several biomarker precursor product pathways in maturation studies initial variations due to depositional conditions have therefore to be taken into account

spatial and temporal patterns of off slope sediment delivery for small catchments subject to shallow landslides within the waipaoa catchment new zealand abstract the waipaoa catchment in new zealand has one of the highest measured specific suspended sediment yields measured in new zealand compared to basins of comparable size a significant source of this sediment is from shallow landslides which are often triggered on a regional scale during large magnitude storm events defined as 200 mm rainfall within 72 h the first step of this sediment cascade is removal of landslide material from the slope and into the fluvial system when the debris tail is in physical contact and hence considered connected the difference between the volume of sediment liberated in the event and the volume remaining on the slope immediately following the event is termed the off slope sediment delivery ratio this value ranged from 0 12 to 0 28 for small sub catchments within the waipaoa catchment depending on catchment morphology landslide and triggering event characteristics in the waipaoa catchment a decrease in the catchment sediment delivery ratio is observed as the sub catchment size increased a human induced process which may affect off slope sediment delivery is regolith exhaustion as scars move further upslope in response to removal of preferred weathered material during previous events on the lower sections of slope however it appears that temporal scar migration away from the channels is not prevalent therefore the hypothesis that hillslope relaxation since deforestation is prevalent in this setting is considered null rather the temporal pattern to sediment delivery ratios supports the context of evolving catchment in response to deforestation in the terrain event resistance model

uplift and subsidence associated with the great aceh andaman earthquake of 2004 rupture of the sunda megathrust on 26 december 2004 produced broad regions of uplift and subsidence we define the pivot line separating these regions as a first step in defining the lateral extent and the downdip limit of rupture during that great m w 9 2 earthquake in the region of the andaman and nicobar islands we rely exclusively on the interpretation of satellite imagery and a tidal model at the southern limit of the great rupture we rely principally on field measurements of emerged coral microatolls uplift extends from the middle of simeulue island sumatra at 2 5 n to preparis island myanmar burma at 14 9 n thus the rupture is 1600 km long the distance from the pivot line to the trench varies appreciably the northern and western andaman islands rose whereas the southern and eastern portion of the islands subsided the nicobar islands and the west coast of aceh province sumatra subsided tilt at the southern end of the rupture is steep the distance from 1 5 m of uplift to the pivot line is just 60 km our method of using satellite imagery to recognize changes in elevation relative to sea surface height and of using a tidal model to place quantitative bounds on coseismic uplift or subsidence is a novel approach that can be adapted to other forms of remote sensing and can be applied to other subduction zones in tropical regions

simultaneous long term and short term slow slip events at the hikurangi subduction margin new zealand implications for processes that control slow slip event occurrence duration and migration 1 we document a sequence of simultaneous short term and long term slow slip events sses at the hikurangi subduction zone during the 2010 2011 period the sequence of short term events each 2 3 weeks in duration ruptured much of the shallow plate interface 15 km at central and northern hikurangi over a 6 month period was accompanied by microseismicity and involved patchy irregular migration of sse slip we suggest that the patchy migration of the short term sse is due to large scale 100 3500 km heterogeneities on the plate interface related to seamount subduction and sediment subduction and or underplating this is in contrast to a 2010 2011 long term sse at the central hikurangi margin which evolved steadily over 1 5 years and ruptured much of the plate interface between 20 and 70 km depth we suggest that the occurrence of long term versus short term sses at hikurangi is related to differences in effective normal stresses and relative heterogeneity of the subduction interface the long term sse sequence began 1 year before the short term sequence coulomb stress change models suggest that the long term sse may have triggered initiation of the subsequent short term sse sequence initiation of the short term sequence occurred in a region just updip of or within an interseismically locked portion of the plate interface and may be located within the updip transition from seismic to aseismic behavior alternatively it could be characteristic of a region undergoing partial interseismic coupling this is in contrast to sses observed elsewhere in the world that typically occur within the downdip transition from seismic to aseismic behavior

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

the geology petrology palynology and geochemistry of permian coal basins in tanzania 2 songwe kiwira coalfield abstract this study provides coal quality petrological palynological and geochemical rock eval data on permian coal seams and associated shales and mudstones of the karoo supergroup of the songwe kiwira coalfield tanzania the coal seams which have a cumulative thickness of 6 80 m occur in the shale coal sandstone facies of the mchuchuma formation of artinskian to kungurian age coal quality data calorific values volatile matter contents and vitrinite reflectances indicate high volatile c bituminous to high volatile a bituminous coals having relatively high ash yields 22 49 wt and highly variable sulphur contents 0 17 9 2 wt they could be used to fuel small scale power generation units thereby providing electricity to nearby towns and villages also the coals could be used as a substitute for wood which is becoming increasingly scarce in rural tanzania charcoal is still the main energy source for cooking and wood is used extensively in brick kilns and for making roofing tiles petrological analysis indicated that the coals are dominated by dull to banded dull lithotypes with seams at the base of the mchuchuma formation enriched in inertinite macerals up to 83 vol whereas up section vitrinite contents increase palynological analyses indicated that the assemblage in the lower mchuchuma formation scheuringipollenites assemblage is dominated by trilete spores whereas in the remainder of the section non taeniate disaccates dominate scheuringipollenites protohaploxypinus assemblage facies critical macerals suggest for most seams a marsh wet forest swamp depositional setting which is consistent with the palynological data rock eval analyses indicate type ii iii kerogen with tmax c values ranging from 426 to 440 corresponding to the early stage of hydrocarbon generation thermal alteration indices 2 to 2 and vitrinite reflectance levels 0 60 0 83 ro support the rock eval maturity assessment and despite the predominance of terrestrial derived organic matter there is evidence of oil generation and expulsion in the form of cavity and fracture filling exsudatinite

active upper plate thrust faulting in regions of low plate interface coupling repeated slow slip events and coastal uplift example from the hikurangi margin new zealand 1 contractional fore arc faulting and deformation is a characteristic feature of many subduction systems definition of the three dimensional geometry and displacement rates of active upper plate out of sequence thrust faults along 250 km of the upper hikurangi margin enables us to examine the relationship between fore arc deformation and the subduction interface in light of interseismic coupling estimates and distribution of slow slip events both modeled from gps measurements these mid fore arc structures include the seaward vergent outer shelf lachlan and ariel faults with vertical separation rates up to 5 mm yr and several other major inner shelf faults with rates that are up to 3 8 mm yr and comparable with holocene coastal uplift rates seismic reflection imaging and geometric projection of these faults at depth indicate that they splay from the region of the plate interface where geodetic inversions for interseismic coupling and slow slip events suggest that the plate boundary undergoes aseismic slip this observation may indicate either 1 that frictional properties and interseismic coupling on the plate interface are independent and unrelated to the active splay fault deformation in the inner middle fore arc or 2 that the active splay faulting reflects long term mechanical coupling related to higher shear stress or the relative yield strength of the plate interface to the overriding plate and that the current pattern of interseismic coupling may not be persistent over geological time scales of 20 ka we compare structure and processes on the northern hikurangi and costa rican margins and find similarities and significant differences astride these subduction systems

age and height distribution of holocene transgressive deposits in eastern north island new zealand abstract holocene transgressive deposits are frequently exposed near the present day coastline of the study area along eastern north island new zealand they occur in sites of former estuaries that were filled during the postglacial rise in sea level we present one hundred radiocarbon dates of holocene transgressive deposits from the study area ranging in age from ca 10 000 to 5500 yr b p relative sea level curves up to ca 6000 yr b p were reconstructed for six locations the curves have similar slopes prior to about 7000 yr b p indicating that sea level rise was much more rapid than any tectonic uplift at that time the postglacial rise in sea level in new zealand is considered in general to have culminated at about 6500 yr b p but the upper limit ages of transgressive deposits in our study area vary from ca 5500 to 7000 yr b p at sites where the uplift rate is high the postglacial transgression culminated rather earlier than ca 6500 yr b p and at sites where there is subsidence or there is very low uplift the culmination is later than ca 6500 yr b p nine of fourteen dates from fossil trees in growth position that grew in and were buried by estuarine silt cluster in the age range ca 8000 8400 yr b p these data support the view that there was a minor regression or stillstand in the eustatic sea level rise at that time eleven tectonic subregions are recognized in the study area on the basis of average uplift rate most of these subregions coincide with those established from the number and ages of younger holocene marine terraces of probable coseismic origin

sedimentology organic geochemistry and petroleum potential of jurassic coal measures tarim junggar and turpan basins northwest china lower and middle jurassic coal bearing strata occur widely throughout central asia and are well developed in northwestern china where their thicknesses in the southern junggar northern tarim and turpan basins exceed 2500 2300 and 1500 m respectively examination of these strata along 13 transects across basin margin outcrop belts indicates that they are entirely nonmarine meandering fluvial deposits with local development of braided fluvial and lacustrine deltaic facies chinese subsurface data suggest that regional jurassic lacustrine facies are present down depositional dip consistent with predictions from global circulation modeling of early and middle jurassic monsoonal precipitation laboratory analyses of coals and organic rich shales show a dominance of terrestrial higher plant components visual kerogen analysis indicates that vitrinite inertinite and exinite are the dominant macerals and elemental analysis characterizes most kerogens as type iii rock eval analyses yield moderate hydrogen index values 50 300 and very low oxygen index values 20 jurassic source rock extracts are characterized by odd over even normal alkane distributions high pristane phytane and high hopane sterane ratios dominance of c29 sterane homologs local abundance of diterpenoid compounds and low abundance of tricyclic terpanes geochemical correlation with four petroleums from the junggar tarim and turpan basins strongly suggests that the jurassic coaly deposits and their lacustrine equivalents downdip are petroleum source rocks sterane and hopane distributions of petroleums and extracts of their putative jurassic source rock are similar and can be easily distinguished from published distributions of these compounds in other source rock layers additional correlation parameters include high pristane phytane low abundance or lack of tricyclic terpanes but similar distributions where present and lack of gammacerane with one exception and carotanes compounds that characterize permian and ordovician source rocks and their respective petroleums pyrolysis gas chromatography of selected jurassic samples s ggests that they possess potential for liquid hydrocarbon generation expulsion of c15 hydrocarbons from jurassic source rocks appears likely despite the traditional view that bituminous coals are incapable of expelling long chain hydrocarbons end page 929

oleanane parameter verification by quantitative study of the biomarker occurrence in sediments of the niger delta abstract the variation of the absolute concentration of oleananes in three selevted sedimentary columns of the tertiary niger delta is paralleled by the corresponding oleanane parameter op profile thereby confirming that the latter can be utilized for estimating the relative contribution of terrigenous organic matter it is shown that op features a dynamic range especially at the oil generative window ogw and can precisely delimit the top of the ogw which for the niger delta is shown to coincide approximately with the 80 c isotherm and ro 0 55 this study provides the first direct evidence of the inadequacy of vitrinite reflectance as a maturity parameter for type iii kerogen furthermore based on the new findings an alternative model for oleanene oleanane interconversions in the geosphere is proposed

hikurangi margin tsunami earthquake generated by slow seismic rupture over a subducted seamount abstract tsunami earthquakes generate much larger tsunami than their surface wave magnitude would suggest and are a problem for tsunami warning systems they are often not accompanied by intense or even strong ground shaking and hence do not provide a natural warning for self evacuation the lesser known 1947 offshore poverty bay and tolaga bay earthquakes along the east coast of the north island new zealand share many characteristics with other well known tsunami earthquakes including low amplitude shaking long durations and anomalously large tsunami however these two new zealand events are rare in that their source area has been imaged directly by long offset 2d seismic reflection profiles in this contribution we propose a source model for the 1947 offshore poverty bay tsunami earthquake recognising that the hypocentre occurs in a region where seismic reflection and magnetic data support the existence of a shallow m 7 earthquakes with complex low velocity rupture scenarios that enhance tsunami waves and their role in seismic hazard should not be under estimated

coastal uplift mechanisms at pakarae river mouth constraints from a combined holocene fluvial and marine terrace dataset abstract one of the major environmental controls on sedimentary systems is tectonics and thus in order to make quantitative explanations and predictions of the behaviour of sedimentary systems it is important to quantify tectonic rates and mechanisms in this study we show how a combined holocene fluvial and marine terrace dataset can be used to place constraints on coastal uplift mechanisms at pakarae river mouth to the east of the waipaoa sedimentary system mapping and surveying of fluvial terraces shows that the terraces can be divided into three sets i pgt a fill terrace formed during post glacial sea level rise 10000 7000 cal yr bp ii a sequence of post 7000 cal yr bp degradation terraces and iii historical post ad 1880 flood terraces a conceptual model of terrace evolution proposes that coseismic uplift has resulted in the observed back tilting downstream divergence and successive abandonment of tectonic terraces coastal uplift mechanisms are then examined by comparing the fluvial and marine terrace uplift distribution and the uplift per event from the marine terraces with those predicted by forward elastic dislocation models the models agree with the interpretation that the terrace uplift can be explained by coseismic slip on a steeply west dipping reverse fault located close to the shore possibly in combination with rupture of the hikurangi margin subduction interface 10 24 km below this study also provides insights into the tectonic drivers and impacts on the adjacent waipaoa sedimentary system including the possible role of subduction earthquakes growth of structures on the shelf and upper slope and the role that the interplay between sea level and tectonic controls has on sediment dispersal

holocene coastal uplift in the western pacific rim in the context of late quaternary uplift abstract this paper reviews recent studies of holocene coastal uplift in tectonically active areas near the plate boundaries of the western pacific rim emergent holocene terraces exist along the coast of north island of new zealand the huon peninsula of papua new guinea the japanese islands and taiwan these terraces have several features in common all comprise series of subdivided terraces the highest terrace is a constructional terrace underlain by estuarine or marine deposits and the lower terraces are erosional cutting into transgressive deposits or bedrock the highest terrace records the culmination of holocene sea level rise at ca 6 6 5 ka bp lower terraces were coseismically uplifted repeated major earthquakes have usually occurred at ka intervals and meter scale uplift the maximum uplift rate and number of terraces are surprisingly similar about 4 m ka and seven to four major steps in north island huon peninsula and japan taiwan especially along the east coast of the coastal range is different reaching a maximum uplift rate of 15 m ka with 10 subdivided steps they record a very rapid uplift comparison between short term holocene and long term since the last interglacial maximum sub stage 5e uplift rates demonstrates that a steady uplift rate huon peninsula or accelerated uplift toward the present several areas of japan and north island has continued at least since isotope sub stage 5e rapid uplift in eastern taiwan probably started only in the early holocene judging from the absence of any older marine terraces most of the causative faults for the coastal uplift may be offshore reverse faults branched from the main plate boundary fault but some of them are onshore faults which deformed progressively with time

non steady long term uplift rates and pleistocene marine terrace development along the andean margin of chile 31 s inferred from 10be dating pleistocene uplift of the chilean coast is recorded by the formation of wave cut platforms resulting from marine erosion during sea level highstands in the altos de talinay area 31 s we have identified a sequence of 5 wave cut platforms using in situ produced 10be exposure ages we show that these platforms were formed during interglacial periods at 6 122 232 321 and 690 ka these ages correspond to marine isotopic stages mis or substages miss 1 5e 7e 9c and 17 shoreline angle elevations used in conjunction with our chronology of wave cut platform formation illustrate that surface uplift rates vary from 103 69 mm ka between 122 and 6 ka to 1158 416 mm ka between 321 and 232 ka the absence of preserved platforms related to the mis 11 13 and 15 highstands likely reflects slow uplift rates during these times we suggest that since 700 ka the altos de talinay area was predominantly uplifted during 2 short periods following mis 17 and miss 9c this episodic uplift of the chilean coast in the pleistocene may result from subduction related processes such as pulses of tectonic accretion at the base of the forearc wedge

seismic reflection character of the hikurangi subduction interface new zealand in the region of repeated gisborne slow slip events summary we use seismic reflection data to map the geometry and character of the subduction interface in the gisborne area of the hikurangi subduction margin new zealand which experiences repeated shallow 15 km slow slip events the reflection character and geometry in this area is highly variable which we interpret to be related to the subduction of seamounts and underthrust sediments three zones of high amplitude interface reflectivity hrz 1 2 and 3 are interpreted to be the result of fluid rich sediments that have been entrained with subducting seamounts the interface above the hrz zones is shallower than the surrounding areas by 2 4 km due to the warping of the interface to accommodate seamount subduction these zones of high amplitude reflectivity and shallower interface geometry correlate broadly with locations of recorded slow slip events from 2002 to 2008 we hypothesize that effective stresses on the interface may be lower along the northeast margin in areas of high amplitude reflectivity due to 1 the enhanced underthrusting of fluid rich sediment 2 reduced overburden stresses where the interface has been warped to shallower depths to accommodate seamount subduction and 3 potential fluid flow concentration effects leading to overpressure along these shallower interface corrugations from our observations we propose localized reductions in effective stress caused by interface structural relief may be a potential factor in promoting shallow slow slip events

late holocene coseismic uplift on the hua tung coast eastern taiwan evidence from mass mortality of intertidal organisms abstract the evidence of coseismic uplift on the dynamic wave dominated hua tung coast fringing the active coastal range eastern taiwan has been equivocal due to complex controls by wave and terrestrial sediment over morphological and ecological systems of the coast this study by applying radiocarbon dating methods demonstrates coseismic uplift nature of the coast by finding synchronously killed intertidal organisms mostly boring shell jouannetia sp stranded at different sites of the coast with distinct physiographic characters based on these data together with evidence from wave cut notch sequences two coseismic uplift systems are recognized one centers around the northern middle part of the coast and yields events with uplift amounts of maximal 3 6 m and an average recurrence interval of at least several hundred years the most recent activity of this system influencing at least 70 km of coast occurred at 0 9 ka the earthquake generating this event also triggered extensive landslides debris flows in the region another system exemplified by the uplift associated with the 2003 cheng kung earthquake centers on the southern part of the coast and yields uplift of likely

liquid hydrocarbon generation potential from tertiary nyalau formation coals in the onshore sarawak eastern malaysia tertiary coals exposed in the north central part of onshore sarawak are evaluated and their depositional environments are interpreted total organic carbon contents toc of the coals range from 58 1 to 80 9 wt and yield hydrogen index values ranging from 282 to 510 mg hc g toc with low oxygen index values consistent with type ii and mixed type ii iii kerogens the coal samples have vitrinite reflectance values in the range of 0 47 0 67 ro indicating immature to early mature initial oil window t max values range from 428 to 436 c which are good in agreement with vitrinite reflectance data the tertiary coals are humic and generally dominated by vitrinite with significant amounts of liptinite and low amounts of inertinite macerals good liquid hydrocarbons generation potential can be expected from the coals with rich liptinitic content 35 this is supported by their high hydrogen index of up to 300 mg hc g toc and py gc s 2 pyrograms with n alkane alkene doublets extending beyond c30 the tertiary coals are characterised by dominant odd carbon numbered n alkanes n c23 to n c33 high pr ph ratio 6 8 high t m t s ratio 8 16 and predominant regular sterane c29 all biomarkers parameters clearly indicate that the organic matter was derived from terrestrial inputs and the deposited under oxic condition

national seismic hazard model for new zealand 2010 update a team of earthquake geologists seismologists and engineering seis mologists has collectively produced an update of the national probabilistic seismic hazard psh model for new zealand national seismic hazard model or nshm the new nshm supersedes the earlier nshm published in 2002 and used as the hazard basis for the new zealand loadings standard and numerous other end user applica tions the new nshm incorporates a fault source model that has been updated with over 200 new onshore and offshore fault sources and utilizes new new zealand based and international scaling relationships for the parameterization of the faults the dis tributed seismicity model has also been updated to include post 1997 seismicity data a new seismicity regionalization and improved methodology for calculation of the seismicity parameters probabilistic seismic hazard maps produced from the new nshm show a similar pattern of hazard to the earlier model at the national scale but there are some significant reductions and increases in hazard at the regional scale the national scale differences between the new and earlier nshm appear less than those seen between much earlier national models indicating that some degree of consis tency has been achieved in the national scale pattern of hazard estimates at least for return periods of 475 years and greater online material table of fault source parameters for the 2010 national seismic hazard model

the kinematics of a transition from subduction to strike slip an example from the central new zealand plate boundary 1 we develop a kinematic model for the transition from subduction beneath the north island new zealand to strike slip in the south island constrained by gps velocities and active fault slip data to interpret these data we use an approach that inverts the kinematic data for poles of rotation of tectonic blocks and the degree of interseismic coupling on faults in the region convergence related to the hikurangi subduction margin becomes very low offshore of the northern south island indicating that in this region the majority of the relative plate motion has been transferred onto faults within the upper plate as suggested by previous studies this result has implications for understanding the likely extent of subduction interface earthquake rupture in central new zealand easterly trending strike slip faults such as the boo boo fault are the key features that facilitate the transfer of strike slip motion from the northern south island faults further north into the southern north island and onto the hikurangi subduction thrust our results also indicate that the transition from rapid forearc rotation adjacent to the hikurangi subduction margin to a strike slip dominated plate boundary with negligible vertical axis rotation in the south island occurs via a crustal scale hinge or kink in the upper plate compatible with paleomagnetic and structural geological data despite the ongoing tectonic evolution of the central new zealand region our study highlights a remarkable consistency between data sets spanning decades gps thousands of years active faulting data and millions of years paleomagnetic data and bedrock structure