classification of huminite iccp system 1994 abstract in the new classification iccp system 1994 the maceral group huminite has been revised from the previous classification iccp 1971 int handbook coal petr suppl to 2nd ed to accommodate the nomenclature to changes in the other maceral groups especially the changes in the vitrinite classification iccp 1998 the new vitrinite classification iccp system 1994 fuel 77 349 358 the vitrinite and huminite systems have been correlated so that down to the level of sub maceral groups the two systems can be used in parallel at the level of macerals and for finer classifications the analyst now has according to the nature of the coal and the purpose of the analysis a choice of using either of the two classification systems for huminite and vitrinite this is in accordance with the new iso coal classification that covers low rank coals as well and allows for the simultaneous use of the huminite and vitrinite nomenclature for low rank coals

organic geochemical proxies of paleoceanographic paleolimnologic and paleoclimatic processes abstract organic matter constitutes a minor fraction of marine and freshwater sediments yet its important contribution to the sedimentary record can be used to reconstruct marine and continental paleoenvironments the organic matter content of sediments is the residue of past biota the amounts and types of organic matter present in sediments consequently reflect environmental conditions that impacted ecosystems at different past times general sources of the organic matter are inferred from bulk properties such as elemental compositions carbon and nitrogen stable isotope ratios rock eval pyrolysis data and organic petrography details of organic matter origins are refined by analyses of biomarker molecular compositions source changes are proxies for fluctuations in sea level oceanic surface currents and continental climates algal paleoproductivity rates are indicated by organic carbon mass accumulation rates and carbon and nitrogen stable isotopic compositions these parameters record past availability of nutrients and therefore are proxies of surface mixing in the oceans and amount of land runoff to lakes sea surface paleotemperatures are recorded by the number of carbon carbon double bonds in lipid biomarkers produced by marine algae larger proportions of the double bonds are proxies for the cooler surface waters that accompanied periods of global glaciation and intervals of enhanced upwelling the 13c and d values of plant organic matter record past concentrations of carbon dioxide in the atmosphere and changes in delivery of atmospheric moisture respectively diagenesis which causes the concentration and composition of organic matter in sedimentary settings to differ from those of the original biologically synthesized materials can bias organic geochemical paleoenvironmental records the magnitude of this potential source of misinformation must always be considered and evaluated comparison of multiple organic geochemical proxies of past conditions helps to compensate for the effects of diagenetic alterations and thereby to improve interpretations of paleoenvironmental change

composition of size fractioned sedimentary organic matter in coastal environments is affected by difference in physical forcing strength the diagenesis of sedimentary organic matter som in three different depositional environments in south texas and dominated by vascular plant input was investigated sediments were collected from mcguill lake a small freshwater lake and two salt marsh sites in nueces delta and copano bay and size fractioned by wet sieving physical forcing or energy indicated by tides tidal current and wind and wind fetch area is weakest in the lake intermediate strength at the nueces delta and strongest at copano bay results from total hydrolyzable amino acid thaa and n alkane analysis and 13c solid state nuclear magnetic resonance spectroscopy nmr showed that the som from all three sites became more degraded towards finer size fractions from 300 m 300 125 m 125 63 m 63 32 m to 32 m relative to the coarse fractions the fine fractions were enriched in the degradation indicator aminobutyric acid and in aliphatic and proteinaceous components as shown from nmr spectra and lower c n ratio values this degradation pattern of som with size is typical for sediments from coastal and lacustrine environments however the contents of organic carbon oc thaas and n alkanes were higher in sandy fractions than in silt and clay fractions from mcguill lake sediment suggesting that the som was relatively undegraded in coarse fractions the size distribution of om in the lake could be explained by the weak physical forcing which may not easily break down coarser plant detritus into smaller pieces the trend contrasted with degradation patterns for sediments from nueces delta and copano bay where som was concentrated in the 32 m fraction which may be due to the strong physical forcing the physical forcing effects could also explain the attachment of clay minerals to sand grains in both the lake and nueces delta because of the relatively weak physical forcing effects while no clay attachment to sand grains was found at the copano bay site because of the strong physical forcing effects physical forcing may be an important mechanism in the processing and transport of om from vascular plants and other organic sources in estuaries and bays before the som is exported to coastal oceans

historical changes in organic matter input to the muddy sediments along the zhejiang fujian coast china over the past 160 years abstract the burial of sedimentary organic matter som in large river influenced estuarine coastal regions is affected by hydrodynamic sorting diagenesis and human activities typically the inner shelf region of the east china sea is a major carbon sink for the yangtze river derived fine grained sediments most of the previous work concentrated on studies of surface sediments or used a single proxy in this region in this study two cores from the zhejiang fujian coast were analyzed using bulk toc tn and 13 c toc and molecular biomarker n alkane brassicasterol dinosterol and glycerol dialkyl glycerol tetraether lipids techniques to clarify the sources spatiotemporal distribution and fate of som in the yangtze river estuary and adjacent shelf results indicated that the effects of diagenesis and diffusion on different sedimentary biomarkers resulted in overestimation of the relative contribution of terrestrial organic matter om terr compared with those based on 13 c toc the amount of terrestrial plant organic matter om plant and om terr in sediments decreased offshore in contrast the amount of marine organic matter om marine increased offshore but closer to the yangtze river mouth the amount of soil organic matter om soil increased moreover the amounts of toc om plant and om marine biomarkers increased but om soil and om terr decreased over time in recent decades our study suggests that spatial om distribution patterns in marine shelf sediments were controlled primarily by hydrodynamic sorting and nutrient concentration and temporally diverse patterns were controlled predominantly by anthropogenic influence e g dam construction and soil conservation reclamation and agricultural plantations anthropogenic nutrient input dust storms eutrophication etc and climate events e g interdecadal climatic jump and heavy rain events in the geological period

comparison of lignin phenols and branched isoprenoid tetraethers bit index as indices of terrestrial organic matter in doubtful sound fiordland new zealand abstract the branched isoprenoid tetraether bit index has recently been proposed as a qualitative proxy for the relative amounts of soil and marine derived organic matter om in marine sediments we compare bit values with lignin phenol cuo oxidation products and bulk om proxies in surface sediment samples from doubtful sound a fjord in the southwestern end of new zealand s south island as well as in soils and leaf litter from the local pristine temperate rainforest watershed the region has extreme rates of annual rainfall 7 m year 1 and large mass wasting soil and vegetation events on fjord slopes which results in relatively high fluxes of terrestrial organic matter om terr to fjord sediments sediments contained up to 11 4 w w organic carbon oc with terrestrial to a mixture of terrestrial marine 13 c 24 3 to 28 7 and c n 14 7 36 8 signatures bit values ranged from 0 24 to 0 93 lignin abundance in sediments reported as 8 values mg 8 lignin phenols 100 mg oc 1 ranged from 2 7 to 11 2 a weak correlation was found between concentrations of lignin phenols and bit values r 2 0 313 the likely cause of the differences between the two proxies is differences in the relative amounts of soil om om soil and vegetation intact and detrital transported to the fjord by episodic mass wasting events and gradual accumulation from overland leaching by rainfall and riverine sources interestingly the bit index correlated significantly with bulk sedimentary om om sed proxies 13 c r 2 0 774 c n r 2 0 629 while lignin phenol values 8 exhibited a much weaker correlation with 13 c values r 2 0 320 and no correlation with c n values r 2 0 005 this suggests that om soil represents the dominant fraction of om terr delivered to fjord sediments

efficient sequestration of terrigenous organic carbon in the new britain trench abstract the fate of terrigenous organic carbon octerr in the ocean remains an enigma for four decades hadal trenches the deepest ocean realm 6 11 km deep were recently proposed to be oc depocenters but whether and how much octerr was sequestrated there remain elusive here we conducted comprehensive analyses for four sediment cores from the new britain trench nbt close to papua new guinea to assess source translocation and burial of oc the bulk and molecular radiocarbon data suggest that the nbt landward slope and axis sediments mainly receive young and biogenic rather than petrogenic oc the three endmember mixing model based on 14c 13c and oc contents reveals that sediments of the nbt axis 8225 m comprise relatively high oc contents 0 66 0 08 of which biogenic octerr accounts for 62 10 the high proportion of biogenic octerr was attributed to the selective translocation of octerr enriched coarse particles and rapid delivery of sediments supported by unique v shape feature of the trench in contrast the sediment oc at the oceanward slope is primarily of a marine origin suggesting that octerr was efficiently trapped in the trench bottom it is estimated that the burial rate is 2 75 0 32 g c m 2 yr 1 for oc and 1 69 0 41 g c m 2 yr 1 for octerr in the nbt given a fact that many trenches are close to the landmasses we propose that the hadal trenches may contribute significantly to the burial of octerr in the ocean

the depositional conditions and the palaeoenvironment of the achlada xylite dominated lignite in western makedonia greece abstract the depositional palaeoenvironment of the neogene achlada lignite deposit western makedonia greece was deciphered with respect to the evaluation of the macro petrographic characteristics and the data resulted from coal petrographic analyses the total thickness of the studied lignite seam is 26 m and consists of organic and inorganic alternations the macro petrographic observations suggest extremely high contributions of woody originated tissue xylite from a single tree type among the lignite layers whereas numerous in situ stems and trunks were observed the results of the coal petrographic analysis indicate the dominance of huminite 88 3 vol whereas liptinite and inertinite show much lower values 11 0 vol and 0 7 vol respectively high contribution of mineral matter is also observed in many cases ulminite types a and b are the most abundant macerals whereas the content of ulminite b is followed by the xylite content facies modeling using maceral composition and maceral indices suggested the alternation of forest swamp and reed moor environments where peat accumulated under highly saturated and intensely anoxic conditions a terrestrial origin with wet forest to piedmont plain depositional conditions was suggested by the gelification index gi and tissue preservation index tpi plot a cross plot of the ground water index gwi vs the vegetation index vi suggested swamps under mesotrophic and rheotrophic hydrogeological conditions where the dominant source for the peat was woody vegetation and vegetation high in preservation potential the overall macro and micro characteristics of the achlada lignite suggest a depositional palaeoenvironment that includes three independent parts a the main channel of a meandering river system b the floodplain area and c the oxbow lake the establishment of telmatic limnotelmatic conditions in this palaeoenvironment resulted in the formation of the entire achlada lignite deposit whereas numerous flood episodes interrupted the peat accumulation and resulted in the deposition of clay rich sediments

nitrogen mineralization and immobilization in sediments of the east china sea spatiotemporal variations and environmental implications nitrogen n mineralization and immobilization are important processes of n biogeochemical cycle in marine sediments this study investigated gross n mineralization gnm and nh4 immobilization gai in the sediments from the east china sea esc using 15n stable isotope dilution technique results show that measured rates of gnm and gai ranged from 0 04 to 6 1 g n g 1 d 1 and from undetectable to 9 82 g n g 1 d 1 respectively in general both gnm and gai rates were significantly greater in summer as compared to winter and the high rates occurred mainly in the muddy area and increased gradually from the yangtze estuary to zhe min coastal muddy areas the gnm and gai processes were related closely to sediment temperature ph ammonium nh4 nitrate no3 total organic carbon toc and total nitrogen tn contents in the muddy area while they were associated tightly with sediment temperature ph nh4 toc tn sulfide and fe iii concentrations in the sandy area in addition the total mineralized and immobilized n in the east china sea ecs were estimated to be approximately 2 1 106 t n yr 1 and 2 7 106 t n yr 1 respectively overall these results highlight the importance of n mineralization and immobilization in controlling the n budget in the ecs and improve the understanding of both processes and associated controlling mechanisms in the coastal marine ecosystem

high resolution reconstruction of sedimentary organic matter variability during the holocene in the mud area of the yellow sea using multiple organic geochemical proxies abstract as a result of terrestrial input and local circulation an area containing continuously deposited mud with abundant organic matter om has formed in the yellow sea ys off the shandong peninsula china during the holocene the understanding of temporal variations in sedimentary organic matter som from this mud area helps to evaluate the influences of yellow river discharge and marine productivity on the burial of organic matter in the ys in this study multiple organic geochemical proxies were used to reconstruct holocene changes in som in a sediment core a02c recovered from the mud area of the ys higher total organic carbon toc and biomarker contents during the early holocene relative to the middle and late holocene are attributed to sea level fluctuations the 13c values of toc 13ctoc range from 21 8 to 23 5 becoming more positive from the bottom to the top of the core tmbr terrestrial and marine biomarker ratio values vary from 0 43 to 0 80 with a decreasing trend during the holocene the decrease in tom contribution was related to elevated sea level shifting of the mouth of the yellow river and weakening of the east asian winter monsoon eawm during the holocene a mixing model with three end members based on 13ctoc and tmbr reveals that the contribution of soil om average 42 is higher than that of plant om average 17 simultaneous decreases in the plant om fraction and the marine om fraction occurred around 10 3 8 2 5 9 4 2 and 2 8 kyr bp corresponding to drift ice events in the north atlantic spectral analyses also reveal that all three om fractions exhibit 1015 year periodicity and that the soil and plant om fractions display 1420 year periodicity consistent with the 1000 year cycle of solar activity and the 1500 year cycle of the kuroshio current kc respectively

a novel proxy for terrestrial organic matter in sediments based on branched and isoprenoid tetraether lipids we propose a novel tracer for terrestrial organic carbon in sediments based on the analysis of tetraether lipids using high performance liquid chromatography mass spectrometry hplc ms analysis of terrestrial soil and peats shows that branched tetraether lipids are predominant in terrestrial environments in contrast to crenarchaeol the characteristic membrane lipid of non thermophilic crenarchaeota which is especially abundant in the marine and lacustrine environment based on these findings an index was developed the so called branched and isoprenoid tetraether bit index based on the relative abundance of terrestrially derived tetraether lipids versus crenarchaeol this bit index was applied to surface sediments from the angola basin where it was shown to trace the outflow of the congo river furthermore analyses of particulate organic matter from the north sea showed relatively higher bit indices in water column particulate organic matter near large river inputs a survey of globally distributed marine and lacustrine surface sediments shows that the bit index in these environments correlates with the relative fluvial input of terrestrial organic material making this index generally applicable the new proxy allows the rapid assessment of the fluvial input of terrestrial organic material in immature sediments up to 100 ma old

hydrodynamic sorting and transport of terrestrially derived organic carbon in sediments of the mississippi and atchafalaya rivers abstract over the course of two years four cruises were conducted at varying levels of discharge in the lower mississippi and atchafalaya rivers mr and ar where grab samples were collected from sand and mud dominated sediments the tetramethylammonium hydroxide tmah thermochemolysis method was used to determine sources of terrestrially derived organic carbon oc in these two sediment types to examine the effects of hydrodynamic sorting on lignin sources in river sediments average lignin concentrations in the lower mr were 1 4 1 1 mg goc 1 at english turn et and 10 4 27 4 mg goc 1 at venice using these concentrations annual lignin fluxes to the gulf of mexico from tidal and estuarine mud remobilization at et and venice were 3 1 2 5 10 5 kg and 11 4 30 0 10 5 kg respectively much of the lignin derived materials in muddy sediments appeared to be derived from non woody grass like sources which should decay more quickly than the woody materials typically found in the sandy deposits the average total oc 1 93 0 47 of english turn sands yields an annual flux of 0 34 0 09 10 9 kg lignin flux in the english turn sands 3 6 2 6 mg gc 1 using the numbers above would be 12 2 9 4 10 5 kg the extensive amounts of sand sized woody materials coffee grinds found in the sandy sediments in both the ar and mr are likely derived from woody plant materials this is the first time it has been demonstrated that sandy sediments in the mr provide an equally important pathway compared to muds for the transport of terrestrially derived organic matter to the northern gulf of mexico using the ar average oc in sand 1 16 0 72 we estimated an annual flux of oc to the shelf of 0 13 0 07 10 9 kg lignin flux for ar sands was estimated to be 12 4 12 1 10 5 kg despite the high error associated with these numbers we observe for the first time that the flux of lignin in sandy sediments in the ar to the northern gulf of mexico is comparable to that found in the mr these results further support the likelihood of grain size related hydrodynamic sorting of terrestrially derived organic carbon in the lower mississippi and atchafalaya rivers suggesting that there is a distinct sandy sediment organic fraction contributed by major rivers to the global carbon cycle

flux and fate of yangtze river sediment delivered to the east china sea numerous cores and dating show the yangtze river has accumulated about 1 16 x 10 12 t sediment in its delta plain and proximal subaqueous delta during holocene high resolution seismic profiling and coring in the southern east china sea during 2003 and 2004 cruises has revealed an elongated similar to 800 km distal subaqueous mud wedge extending from the yangtze river mouth southward off the zhejiang and fujian coasts into the taiwan strait overlying what appears to be a transgressive sand layer this distal clinoform thins offshore from similar to 40 in thickness between the 20 and 30 m water depth to 1 2 in between 60 and 90 m water depth corresponding to an across shelf distance of less than 100 km total volume of this distal mud wedge is about 4 5 x 10 11 m 3 equivalent to similar to 5 4 x 10 11 t of sediment most of the sediment in this mud wedge comes from the yangtze river with some input presumably coming from local smaller rivers thus the total yangtze derived sediments accumulated in its deltaic system and east china sea inner shelf have amounted to about 1 7 x 10 12 t preliminary analyses suggest this longshore and across shelf transported clinoform mainly formed in the past 7000 yrs after postglacial sea level reached its mid holocene highstand and after re intensification of the chinese longshore current system sedimentation accumulation apparently increased around 2000 yrs bp reflecting the evolution of the yangtze estuary and increased land erosion due to human activities such as fanning and deforestation the southward flowing china coastal current the northward flowing taiwan warm current and the kuroshio current appear to have played critical roles in transporting and trapping most of yangtze derived materials in the inner shelf and hence preventing the sediment escape into the deep ocean c 2006 elsevier b v all rights reserved

on the fundamental difference between coal rank and coal type abstract this article addresses the fundamental difference between coal rank and coal type while theoretically settled long ago as being different aspects of coal systems science the two concepts are still often confounded in recent years this has resulted in the publication of several works stating that coal type changes with coal rank coal type refers solely to coals depositional origin and the maceral mineral admixture resulting from that origin coal types typically fall in to two categories humic coals developed from peat and sapropelic coals developed from organic mud either type may be allocthonous or autochthonous and within types further refinement of depositional environment can be made coal rank refers to the changes in geochemistry and resultant changes in reflectance caused by increasing thermal maturity of the coal thus it provides an overprint of maturity on existing coal types with proper techniques such as use of crossed polars and etching maceral forms can be differentiated even at high ranks and the original coal type determined

coal as a source rock for oil a review the geological debate about whether and to what extent humic coals have sourced oil is likely to continue for some time despite some important advances in our knowledge of the processes involved it is clear that not only liptinites but also perhydrous vitrinites have the potential to generate hydrocarbon liquids in the course of natural coalification some liptinites especially alginite cutinite and suberinite contain a higher proportion of aliphatic moieties in their structure than other liptinites such as sporinite and resinite and are therefore more oil prone it is of potential value to be able to predict the several environments of deposition in which coals with high liptinite contents or containing perhydrous vitrinites may have been formed review of the distribution of oil prone coals in time and space reveals that most are jurassic tertiary with key examples from australia new zealand and indonesia methods based both on experimental simulations and the examination of naturally matured samples have been used to determine the order of generation of hydrocarbons from different macerals results are not entirely consistent among the different approaches and there is much overlap in the ranges of degradation but it seems probable that in the natural environment vitrinites begin to generate early followed by labile liptinites such as suberinite then cutinite sporinite and finally alginite petroleum potential may be determined by experimental simulation of natural coalification or inferred through various micro techniques especially fluorescence and infrared ir spectroscopy or bulk techniques such as elemental analysis and 13c nmr spectroscopy the latter three techniques enable a measure of the polymethylene component of the coal which now appears to be one of the best available approaches for determining petroleum potential no method of experimental simulation of petroleum generation from coals is without criticism and comparative results are highly variable however hydrous pyrolysis confined pyrolysis and forms of open system hydrous pyrolysis approach acceptable simulations whether and to what degree generated liquid hydrocarbons are expelled has long been the central problem in oil from coal studies the structure of vitrinite was believed until recently to contain an interconnected microporous network in which generated oil would be contained until an expulsion threshold was attained recent studies show the pores are not interconnected combined with a dynamic model of pore generation it now seems that expulsion of hydrocarbons is best explained by activated diffusion of molecules to maceral boundaries and ultimately by cleats and fractures to coal seam boundaries the main reason for poor expulsion is the adsorption of oil on the organic macromolecule which may be overcome 1 if coals are thin and interbedded with clastic sediments or 2 if the coals are very hydrogen rich and generate large quantities of oil the existence of oil in vitrinite is attested to by solvent extractions fluorescence properties and by microscopic observations of oil and bitumen experimental simulation of expulsion of oil from coals has only recently been attempted the relative timing of release of generated co2 and ch4 could have considerable importance in promoting the expulsion of liquid hydrocarbons but the mechanism is unclear as it is universally agreed that dispersed organic matter dom in some shales readily generates and expels petroleum it is curious that few consistent geochemical differences have been found between coal macerals and dom in interbedded shales unambiguous evidence of expulsion from coals is limited and in particular only a few commercial oil discoveries can be confidently correlated to coals these include upper cretaceous fruitland formation coals in the usa from which oil is produced new zealand tertiary coals and middle jurassic coals from the danish north sea it is likely that coals have at least contributed to significant oil discoveries in the gippsland basin australia in the turpan basin china and in the kutei and ardjuna basins in indonesia but this remains unproven early reports that early jurassic coals in mid norway were a major source of the reservoired oils have been shown to be inaccurate none of the proposed rules of thumb for generation or expulsion of petroleum from coals seem particularly robust decisions on whether a particular coal is likely to have been an active source for oil should consider all available geological and geochemical information the assumptions made in computational models should be well understood as it is likely with new understandings of processes involved that some of these assumptions will be difficult to sustain

influences of tropical monsoon climatology on the delivery and dispersal of organic carbon over the upper gulf of thailand abstract organic carbon cycling in se asia is data sparse and poorly studied although high sediment yield and organic carbon intensity occur in the tropical region in the present study we evaluated the role of tropical monsoon pertaining to fluvial discharge sediment load coastal current and water stratification on seasonal organic carbon dynamics during four sampling campaigns in the upper gulf of thailand ugot this study demonstrates that particulate organic carbon poc is closely correlated with the river influx of suspended sediment which is generally regulated by the local rainfall higher poc is found near the large estuarine section chao phraya river chao during southwest monsoon period and the small estuarine section mae klong river mk during november 2013 when tropical cyclones impacted poc in the estuarine sections is more significantly influenced by the seasonal shift compared with the coastal sections land derived organic matter prevails in the small estuarine and coastal sections while marine derived organic matter dominates in the estuarine sections impacted by chao and mk anthropogenic inputs and dam regulation also influences the river export of organic matter during the high precipitation periods total organic carbon toc however displays less significant seasonal monsoon variations than poc further toc tends to accumulate in the sub silt fraction of sediments which mainly occurs in the small estuarine and eastern coastal sections and is more obviously influenced by marine derived factors toc in sediment of the chao and mk influenced sections however displays more seasonal variations with prevailing river input evidenced by coarser sediment and higher c n ratios moreover the almost year round water stratification across the region acts as the barrier in retaining organic carbon in the estuaries and their vicinities from dispersal into the lower portion of gulf of thailand high sedimentation rate 1 1 cm yr 1 further facilitates the organic carbon burial in the study area the delivery dispersal and burial of organic carbon are closely associated with the climate controlled precipitation and thus the tropical monsoon climatology under the global warming in particular is an important factor influencing the organic carbon in the ugot

sulfur and iron diagenesis in temperate unsteady sediments of the east china sea inner shelf and a comparison with tropical mobile mud belts mmbs redox cycling of iron fe and sulfur s exerts profound influences on fates of numerous elements in coastal marine sediments in this study s and fe cycling and its geochemical expressions in the east china sea ecs inner shelf a representative of temperate mobile mud belts mmbs were characterized and compared with tropical counterparts the amazon shelf and the gulf of papua fe and s speciation consistently points to the dominance of authigenic nonsulfidized fe ii phases i e poorly crystalline clays pccs and carbonates and the prevalence of fe redox cycling in the suboxic or weakly sulfidic regimes of the ecs mmbs high contents of authigenic magnetite may be a common diagenetic expression in all mmbs compared to the tropical mmbs three main differences of diagenetic expressions in the ecs mmbs are i light 34spyrite in the ecs mmb vs characteristically heavy 34spyrite in the amazon shelf mmbs ii lower total reactive fe fetr total diagenetic fe ii and ratio of fetr to total fe in the ecs mmbs iii fe ii carbonates and pccs are equally important sinks for nonsulfidized fe ii in the ecs mmbs whereas pccs are the predominant sink in the tropical counterparts these differences are ascribable to factors including low degradability of organic matter small diffusion scales less intense chemical weathering in the drainage basin and or weaker reverse weathering in the ecs mmbs despite the differences above fe and s diagenetic expressions that characterize the prevalence of fe redox cycling in the unsteady suboxic regimes are shared by the ecs and tropical mmbs

centers of organic carbon burial and oxidation at the land ocean interface abstract continental margin systems collectively receive and store vast amounts of organic carbon oc derived from primary productivity both on land and in the ocean thereby playing a central role in the global carbon cycle the land ocean interface is however extremely heterogeneous in terms of terrigenous input marine primary productivity sediment transport processes and depositional conditions e g such as bottom water oxygen level continental margins are also highly dynamic with processes occurring over a broad range of spatial and temporal scales the rates of oc burial and oxidation are consequently variable over both space and time hindering our ability to derive a global picture of oc cycling at the land ocean interface here we review the processes controlling the fate of organic matter in continental margin sediments with a special emphasis on hot spots and hot moments of oc burial and oxidation we present a compilation of compositional data from a set of illustrative settings including fjords small mountainous river margins large deltaic systems and upwelling areas bulk oc stable isotope and radiocarbon compositions reveal the diversity and complexity characteristic of oc buried in marginal seas this primarily relates to differences in marine and terrestrial inputs the composition of the terrestrial component e g vascular plant oc soil and petrogenic oc inputs and processes modulating the fate of oc within the marine environment e g priming this widely contrasting behavior of oc among these systems illustrates that the reactivity of oc is a product of its chemical composition and regional conditions interpreted in the context of bulk compositional data as well as that obtained on specific molecular markers e g lignin derived phenols the possibility exists to tease apart complex mixtures of terrestrial and marine inputs and to shed light on the role of the myriad of depositional and post depositional processes finally we discuss a set of hot topics that warrant further investigation such as the role of photochemistry fungi halogenation and reactive iron in dictating the fate of oc in the changing coastal ocean

the miocene coal seams in the soma basin w turkey insights from coal petrography mineralogy and geochemistry abstract the neogene soma basin western turkey hosts three coal seams km2 km3 and kp1 and several altered tuff layers within the miocene sequences this study focuses on the evaluation of coal petrography mineralogical and elemental compositions as well as the rock eval pyrolysis of the three coal seams from eynez isiklar and denis sectors and to identify the mineralogy of altered tuff layers within km2 and kp1 seams the routine coal quality analyses show that coal samples from the km2 seam are characterized by lower ash yields and total s contents and higher gross calorific values than km3 and kp1 seams the mineralogical composition of the bulk coal samples varies between all three seams the statistical treatment implies that major elements in bulk coal samples such as al fe k mg and na and the vast majority of minor and trace elements have inorganic affinity the trace element contents and elemental enrichments in the coal samples are generally changeable from seam to seam which could be related to differences in ash yield and mineralogy altered tuff layers or tonsteins were identified in km2 and kp1 seams the tonsteins are clay rich and certain trace elements e g as and zr are enriched in the coal layers beneath the tuff layers in the km2 seam this might be related to penetration of leached pore water into these layers and precipitation of epigenetic minerals the coal petrography composition and the coal facies diagrams show that the precursor peat of the km2 seam was accumulating under telmatic mesotrophic anoxic conditions whereas the water level was high and stable the relatively low ash yields and thicker coal beds suggest a lower clastic input from the basin margins and water table fluctuations resulted in calcareous intercalations in the km3 and kp1 seams these imply the development of limno telmatic conditions whereas fluvial activity affected during peat accumulation of both seams considering the maceral composition along with the coal thickness coal seams in the soma basin might display oil generation potential however the pyrolysis analysis shows that the studied coal seams are mainly gas prone and only certain coal beds have mixed hydrocarbon generation capacity all data presented in this study indicates that lithological features differences in coal qualities and elemental contents in the soma basin were mainly controlled by changes in the depositional conditions and the detrital input during miocene

distribution and origin of minerals in high rank coals of the south walker creek area bowen basin australia the coals of the south walker creek area in the northern bowen basin with a vitrinite reflectance rvmax of 1 7 to 1 95 are among the highest rank coals currently mined in australia x ray diffraction studies have identified an unusual mineral variation through the vertical sequence with kaolinite rich assemblages typical of other australian coals at the top and bottom of the seam section and an illite chlorite assemblage resembling a metamorphic association in the middle calcite and ankerite are also abundant in parts of the vertical sequence diaspore is abundant in the middle section of the seam in some areas and paragonite dickite or nacrite occurs in some locations as well the distribution of the non carbonate mineral assemblages cross cuts the seam stratigraphy and appears to be primarily controlled by faults and other structural features integration of the mineral distribution with optical and electron microscope data on the coal and non coal bands chemical data from coal ash analysis and information from x ray micro tomography suggests that the illite chlorite and diaspore bearing assemblages resulted from hydrothermal effects associated with fluid migration through the middle part of the coal seam this is further confirmed by the development of metamorphic textures in a tonstein band also altered to illite and chlorite in the illite rich part of the seam section in contrast to a tonstein with more normal sedimentary textures and a kaolinite composition in the kaolinite rich upper part of the seam detailed studies of cleat mineralisation suggest that fluids rich in ca mg and al were introduced relatively early in the seam s post depositional history associated with heat flow sufficient to alter the minerals in the coal and tonstein in the affected part of the seam section the relatively uniform vitrinite reflectance profile observed through the seam section may indicate that the coal was already of high rank before the fluids were introduced or that any localised heat effects on the organic matter associated with the changes in clay mineralogy were overprinted by subsequent wider ranging rank advance processes

sources and distributions of tetraether lipids in surface sediments across a large river dominated continental margin glycerol dialkyl glycerol tetraether gdgt based proxies are increasingly used in modern carbon cycling and palaeoenvironmental investigations it is therefore crucial to examine the robustness sources transport and degradation of all gdgt based proxies in continental margins where sedimentation rates and extent of carbon cycling are high we have analyzed the distributions of gdgts in surface sediments from the lower yangtze river and east china sea ecs shelf the results revealed multiple sources and complex shelf processes that govern the distributions the isoprenoid gdgt inferred sea surface temperatures ssts are robust and reflect the satellite derived annual mean ssts on the shallow ecs shelf confirming an origin from surface water column dwelling crenarchaeota the input from methanogen sourced isoprenoid gdgts is significant in the river surface sediments but they are almost absent from the ecs shelf branched gdgts are also abundant in the river sediments but ca 95 are degraded in the yangtze estuary a much greater extent than observed for other terrigenous organic matter om proxies there is also evidence for production of branched gdgts in the oxic ecs shelf water column and the anoxic sediments waters of the lower yangtze river as a result branched gdgt based proxies in the lower river and ecs surface sediments do not reflect the catchment environmental conditions the effective degradation in the estuary and widespread aquatic contributions of branched gdgts improves our understanding of how to use branched gdgt based proxies in marginal seas

distributions of bacterial and archaeal membrane lipids in surface sediments reflect differences in input and loss of terrestrial organic carbon along a cross shelf arctic transect enhanced climate warming affecting the arctic region could have a dramatic impact on the terrigenous organic carbon terroc stored in the eurasian permafrost and could increase the amount of oc remobilized to the arctic shelves an improved understanding of the fate of this remobilized soil oc is essential for better understanding of the consequences for the arctic and global carbon cycle in this study glycerol dialkyl glycerol tetraethers gdgts and bacteriohopanepolyols bhps in surface sediments along a 500 km cross shelf transect from the mouth of the kolyma river to the middle of the vast east siberian sea were analysed to assess their potential and that of the associated branched and isoprenoid tetraether bit and r 0 soil indices for tracing terroc in arctic systems both bhp and gdgt contributions indicated the greatest contribution of terroc close to the river mouth while the associated indices showed declining trends in an offshore direction supporting an increasing marine oc input and or a decrease in terroc however while the bhps indicated a dominance of terroc at the start of the transect the gdgts suggested a much larger almost 50 marine oc input at this point in addition the bit index displayed an exponential decline controlled mainly by a substantial contribution of marine gdgts while

mineral matter in low rank coals and associated strata of the mae moh basin northern thailand abstract the mineral and other ash forming constituents in lignites of the mae moh basin in northern thailand have been identified and evaluated in relation to the minerals present in the associated interseam non coal strata and the intra seam non coal bands treatment of the coal with water ammonium acetate and hydrochloric acid shows that a considerable part of the ash forming inorganic matter occurs in water soluble acid soluble or ion exchangeable form although the distribution of elements may be modified by the effects of pyrite oxidation the mobile fraction of the fresh coal is dominated by water soluble ion exchangeable and acid soluble calcium water soluble and exchangeable magnesium water soluble sodium and sulphur and acid soluble iron and aluminium calcium is most abundant especially in coals where a low proportion of silicate minerals quartz clay etc is present it combines readily with the different sulphur forms on combustion to produce an ash with a distinctively high cao and so 3 content the main minerals in the coals are quartz pyrite and a clay fraction consisting of kaolinite illite and an expandable irregular mixed layer mineral the mixed layer clay appears to be more abundant in the coal and illite less so than in the mudrocks of the associated non coal strata the non coal partings within the main seams contain quartz pyrite and a similar clay mineral assemblage but they also contain an abundance of calcite and or aragonite and in some cases consist entirely of carbonate minerals shell fragments and possibly plant replacement structures are present in some of these materials gypsum bloedite hexahydrite and other sulphate minerals and calcite are deposited as fracture fillings and surface coatings on some exposed open cut mine faces

constraints on the application of the mbt cbt palaeothermometer at high latitude environments svalbard norway abstract branched glycerol dialkyl glycerol tetraethers gdgts are membrane lipids of unknown bacteria that are ubiquitous in soil and peat two indices based on the distribution of these lipids in soils the cyclization of branched tetraethers cbt and the methylation of branched tetraethers mbt indices have been shown to correlate with soil ph and mean annual air temperature mat and soil ph respectively and can be used to reconstruct mat in palaeoenvironments to verify the extent to which branched gdgts in marine sediments reflect the distribution pattern on land and whether these proxies are applicable for palaeoclimate reconstruction in high latitude environments with a mat of

the dispersal of sedimentary terrestrial organic matter in the east china sea ecs as revealed by biomarkers and hydro chemical characteristics terrestrial organic matter tom in surface sediments from the lower yangtze river and adjacent east china sea ecs shelf was characterized using elemental stable carbon isotope and molecular analysis the results show that it is heterogeneous and derives from various sources in the lower river transect rc transect and inner shelf transect zj transect but is more homogeneous and presumably derives from a single source in the cross shelf transect pn transect the trends in sedimentary tom abundance indicated by high molecular weight n alkane abundances and distributions lignin derived products 13c values of total organic carbon 13ctoc and ratio of toc to total nitrogen c n suggest a southward off estuary transport mode of tom along the inner shelf transect while counter intuitively the opposite or no trend in tom off estuary transport occur along the cross shelf transect we therefore suggest that yangtze discharged om is transported southwards along the zhejiang fujian coast zj transect and enters the southern okinawa trough via near bottom currents from where it is ultimately delivered back upslope to the middle shelf by the kuroshio invading water consistent with the hydro chemical characteristics of the ecs

trace elements in the lower pliocene fossiliferous kangal lignites sivas turkey abstract the kangal lignite basin which is one of the most productive lignite basins in eastern anatolia turkey includes two lignite seams containing abundant gastropoda shells in the lower pliocene kalburcayiri formation the seams are currently exploited in an open cast mine in the kalburcayiri field and supply feed coal to a power plant with 300 mw capacity the average thickness of each of the two seams in this mine is about 10 m and they are separated by about 20 m of tuffaceous sedimentary rocks a 15 20 cm thick tuff bed occurs within the upper seam the purpose of the study was to understand mineralogy and trace element concentrations of the two lignite seams in the kalburcayiri formation which were affected by volcanic ashes fifty nine core samples of the lignites from seven boreholes across the basin and eight channel samples from the working lignite seams were collected and analysed by proximate analysis x ray powder diffraction xrd inductively coupled plasma mass spectrometry icp ms and scanning electron microscopy sem with energy dispersive x ray microanalysis techniques the samples show that the worked lignite seams on an as received basis contain high moisture contents 43 4 57 8 all the samples on an air dried basis have high ash yields from 19 5 to 81 7 and a broad range of total sulfur contents from 1 16 to 7 04 and calorific values 684 to 4621 kcal kg except for two samples with no temperature rise due to high ash yield the mineral matter of the studied samples is made up of calcite quartz feldspar pyrite opal ct clay minerals gypsum and traces of aragonite the trace element analyses on a whole coal dry basis indicate that most of the borehole samples showed enrichment in specific elements including zn 15 1394 g g mo 13 368 g g and u 5 5 131 g g when compared to the range of these elements for most coals in the world the contents of zn mo and u for the samples from the worked lignite seams are respectively 38 187 54 161 and 28 55 g g the sem studies show that zn is hosted mainly in micron sized zn bearing mineral sphalerite but no mo and u bearing minerals have been detected during these studies except for monazites containing th and u traces the mo and u concentrations are negatively correlated with the ash yields and these elements are contained mainly within organic matter

sources and transport of terrestrial organic matter in vancouver island fjords and the vancouver washington margin a multiproxy approach using d13corg lignin phenols and the ether lipid bit index the branched and isoprenoid tetraether bit index a ratio of marine and terrestrial glycerol dialkyl glycerol tetraether gdgt membrane lipids was recently introduced as a proxy for the fraction of fluvially derived organic carbon oc buried in marine sediments we investigate the source and distribution of terrestrial oc in marine sediments in a large spatial data set that encompasses the washington vancouver island margin vancouver island fjords and puget sound with the goal of comparing the bit index to other traditional measures of terrestrial oc d13 co f oc d13corg and lignin phenols d13corg values and lignin concentrations indicate that the fjords are a significant trap for undegraded wood derived terrestrial material with surface sediments containing up to 76 terrestrial oc these proxies also show significant terrestrial oc contributions to margin sediments up to 54 with most likely an angiosperm source from the columbia river in contrast to d13corg values and lignin concentrations bit index values indicate extremely low terrestrial carbon throughout the study area bit index values range from 0 to 0 28 and are uncorrelated with the other proxies though the bit index did not correlate with other proxies margin gdgt concentrations varied offshore similarly to other terrestrially derived oc and are well correlated with other proxies we suggest that the bit index is best interpreted as a proxy for soil or peat derived oc the majority of terrestrially derived oc delivered to sediment in this area has a lignin rich nonsoil source the disparity between the bit index and other proxies implies that the bit index significantly underestimates terrestrial relative to marine oc input to sediments in areas in which riverine oc input is not soil or peat derived burial of organic carbon oc on continental margins is estimated to account for the majority of the total carbon burial in the ocean and is a significant sink for terrestrial oc hedges and keil 1995 understanding the sources and fate of this terrestrial oc in marine sediments is thus of importance in understanding global biogeochemical cycles in this study we use two traditional proxies for terrestrial oc input to sediments the d 13 c of bulk sedimentary oc d13corg and the concentration of lignin phenols to examine the sources and quantity of terrestrial oc in sediments throughout the washington vancouver island margin vancouver island fjords and puget sound we compare these results to those obtained using a recently introduced proxy for terrestrial oc in marine sediments the branched and isoprenoid tetraether bit index

origin and correlation of tuffs in the permian newcastle and wollombi coal measures nsw australia using chemical fingerprinting abstract felsic tuffs are common throughout the late permian newcastle and wollombi coal measures ncm wcm of the northern sydney basin petrographic studies reveal that they are composed of fragmented crystals of plagioclase quartz and less common degraded biotite and k feldspar together with lithic fragments and relict altered glass shards alteration during burial at t 62 78 kaolinite siderite ankerite and in extreme circumstances tonsteins dominated by i s the latter is formed by the alteration of vitric tuffs zr tio 2 and nb y ratios and rock primordial and chondrite normalised ree patterns la yb 4 05 to 11 37 indicate that the tuffs have been derived from rhyodacitic to dacitic continental arc calc alkaline magmas the accuracy of a recent lithostratigraphic correlations between the ncm and the wcm has been tested by determining the chemical composition of four stratigraphically well defined tuffs in the ncm and comparing them with those obtained from tuffs of the wcm which are thought to be stratigraphically equivalent the comparison was carried out using multivariate statistical analysis the analysis revealed that two of the tuffs awaba nobbys in the ncm could be distinguished the others mt hutton warners bay showed considerable scatter this contrasted with the tonsteins formed from the tuffs which apart from the mt hutton tuff were able to be separated in the wcm three of the tuffs nalleen unnamed tuff equivalent to the mt hutton tuff monkey place creek could be separated however the fourth unnamed tuff equivalent to the warners bay tuff exhibited some scatter treating tuffs in the wcm separately as unknowns in the discriminant model to determine possible correlatives in the ncm revealed that the nalleen tuff is equivalent to the awaba tuff in the ncm confirming the lithostratigraphic correlation the remainder of the tuffs in the wcm however show moderate to poor correlation with the proposed stratigraphically equivalents in the ncm thus the analysis shows that correlation based on lithostratigraphic grounds may be incorrect

chemical evidence of differential particle dispersal in the southern washington coastal environment aliphatic hydrocarbons cupric oxide oxidation products of lignin and polycyclic aromatic hydrocarbons pah were analyzed by capillary gas chromatography in sediments from the southern washington continental shelf and slope the concentration of diploptene relative to plantwax n alkanes increased systematically in surface sediments with distance offshore along east west transects of the study area and remained constant in surface sediments along the midshelf silt deposit analogous trends were also observed for the concentration of cinnamyl phenols relative to vanillyl phenols and total methylphenanthrenes relative to phenanthrene these changes in sedimentary composition are evidence that diploptene from some terrestrial source lignin characteristic of non woody vascular plant tissue and a fossil organic material contained within weathered rock debris disperse across the washington continental shelf and slope in geographic patterns distinct from that for other river derived chemically related materials the compositional variations are explained by the particulate associations of the land derived chemicals and differential hydraulic dispersion of their respective carrier particles after discharge at the mouth of the columbia river

magnetostratigraphy of the dali basin in yunnan and implications for late neogene rotation of the southeast margin of the tibetan plateau 1 the rotation pattern and fault activity in the southeast margin of the tibetan plateau semtp provide meaningful constraints on the geodynamic evolution of the plateau however the lack of cenozoic paleomagnetic studies and accurate age constraints on neogene sediments prevents a better understanding of the late cenozoic tectonic activity in this area to clarify the tectonic rotation pattern and deformation history of the semtp we report new magnetostratigraphic data from a late neogene sedimentary sequence in the dali basin northwestern yunnan province china rock magnetic analyses indicate that both magnetite and hematite are the main carriers of the characteristic remanent magnetizations chrms magnetostratigraphic results show that the sedimentary profile spans from chron c4n 1r to chron c2n the age of the sedimentary sequence in the dali basin can thus be paleomagnetically constrained to an interval from late miocene to early pleistocene the basal age of the sediments is 7 6 ma which indicates that the unroofing of diancang shan and activation of the dali fault system were initiated at this time the appearance of conglomerates and syntectonic sediments suggests the reactivation of the dali fault system at 2 5 ma moreover the overall mean chrm direction suggests that the dali basin experienced significant 4 4 2 5 but minor post late miocene rotation this indicates that most of the clockwise rotation demonstrated by previous paleomagnetic studies in the semtp occurred prior to late miocene and may be concentrated between eocene and miocene which is contemporaneous with the sinistral slip of the ailao shan red river fault

constraints on the sources of branched tetraether membrane lipids in distal marine sediments abstract branched glycerol dialkyl glycerol tetraethers brgdgts are membrane lipids produced by soil bacteria and occur in near coastal marine sediments as a result of soil organic matter input their abundance relative to marine derived crenarchaeol quantified in the bit index generally decreases offshore however in distal marine sediments low relative amounts of brgdgts can often still be observed sedimentary in situ production as well as dust input have been suggested as potential though as yet not well constrained sources in this study brgdgt distributions in dust were examined and compared with those in distal marine sediments dust was sampled along the equatorial west african coast and brgdgts were detected in most of the samples albeit in low abundance their degree of methylation and cyclisation expressed in the mbt methylation index of branched tetraethers and dc degree of cyclisation indices respectively were comparable with those for african soils their presumed source comparison of dc index values for brgdgts in global soils congo deep sea river fan sediments and dust with those of distal marine sediments clearly showed however that distal marine sediments had significantly higher values this distinctive distribution is suggestive of sedimentary in situ production as a source of brgdgts in marine sediments rather than dust input the presence of in situ produced brgdgts in marine sediments means that caution should be exercised when applying the mbt cbt palaeothermometer to sediments with low bit index values i e

sources dispersal and preservation of sedimentary organic matter in the yellow sea the importance of depositional hydrodynamic forcing abstract the sources distribution and fate of sedimentary organic matter som in the yellow sea ys were studied based on the datasets of total organic carbon toc total nitrogen tn organic carbon isotopic values 13 c and n alkanes of forty seven surface sediment samples the spatial pattern of toc and tn coincided with that of the sediment grain size suggesting the hydrodynamic constraints on the accumulation of som in the ys the relatively low toc tn ratios with contrasting tn intercept of the regression lines indicate the influence of the sorption of inorganic n in the nys and a mixture of microorganism derived n rich om pool with the terrigenous n poor om for the sys sediment samples respectively the enriched 13 c could also be partially related to the agriculture inputs due to the enhanced fertilization process in addition to the planktonic derived om molecular compositions of n alkanes and principal component analysis pca showed a significant terrigenous contribution for the som in the central mud deposits the observed even carbon preference of the short chain length n alkanes c 12 c 22 reveals the potential contribution of microorganism derived om in the ys combined lines of evidence of significant terrigenous n alkanes in the ys suggest that the hydrodynamic forcing plays a key role on the selective dispersal and preferential accumulation of the fluvial terrigenous organic materials the simplified terrigenous som transport pathway to the central mud deposits of the ys was conceptually constructed based on the mixed sediments provenances hydrodynamic transport and depositional mechanism of the fine grained sediments in this region

phase mineral and chemical composition of composite samples from feed coals bottom ashes and fly ashes at the soma power station turkey abstract the phase mineral and chemical composition of feed coals fcs and their bottom ashes bas and fly ashes fas produced in the soma thermo electric power station tps turkey was characterized fcs are high ash soma subbituminous coals abundant in moisture and ca and depleted in s the inorganic composition in decreasing order of significance of fcs includes calcite quartz kaolinite illite muscovite chlorite plagioclase gypsum pyrite montmorillonite k feldspar dolomite siderite ankerite opal and volcanic glass the results for 57 elements studied show that ca nb cs v li have significantly higher contents in fc ashes than the respective clarke values for coal ashes the water soluble residues isolated from fcs include gypsum calcite inorganic amorphous matter ca mg na k phase and opal these residues are enriched in na se s b mg mo sr ca k the phase mineral composition of bas and fas includes mainly glass quartz char mullite plagioclase calcite and portlandite and to a lesser extent illite muscovite melilite hematite anhydrite lime cristobalite kaolinite and magnetite minor amounts of k feldspar dolomite ankerite fe spinel gypsum and ca k na phase also occur in bas and fas fas are enriched in inorganic matter glass cristobalite mullite fe oxides lime and anhydrite and depleted in mineral matter char quartz clay minerals melilite portlandite and carbonates in comparison with bas only se is significantly enriched in bas and fas compared to fc ashes most of the trace elements in particular as bi cd ge pb sn tl and w are more abundant in fas while bas are more enriched in ca cs fe ho mn p sc se and tb significant percentages 11 59 of elements initially present in fcs namely s sb sn ta mo bi zn ni na lu tm b were emitted by stack emissions and not captured by the cleaning equipment in the soma tps some genetic features properties possible environmental concerns and potential utilization directions related to fcs bas and fas are also discussed

controls on the age of vascular plant biomarkers in black sea sediments abstract transfer of organic carbon oc from the terrestrial to the oceanic carbon pool is largely driven by riverine and aeolian transport before transport however terrigenous organic matter can be retained in intermediate terrestrial reservoirs such as soils using compound specific radiocarbon analysis of terrigenous biomarkers their average terrestrial residence time can be evaluated here we show compound specific radiocarbon 14c ages of terrigenous biomarkers and bulk 14c ages accompanied by geochemical proxy data from core top samples collected along transects in front of several river mouths in the black sea 14c ages of long chain n alkanes long chain n fatty acids and total organic carbon toc are highest in front of the river mouths correlating well with bit branched and isoprenoid tetraether indices which indicates contribution of pre aged soil derived terrigenous organic matter the radiocarbon ages decrease further offshore towards locations where organic matter is dominated by marine production and aeolian input potentially contributes terrigenous organic matter average terrestrial residence times of vascular plant biomarkers deduced from n c29 31 alkanes and n c28 30 fatty acids ages from stations directly in front of the river mouths range from 900 70 years to 4400 170 years these average residence times correlate with size and topography in climatically similar catchments whereas the climatic regime appears to control continental carbon turnover times in morphologically similar drainage areas of the black sea catchment along transect data imply petrogenic contribution of n c29 31 alkanes and input via different terrigenous biomarker transport modes i e riverine and aeolian resulting in aged biomarkers at offshore core locations because n c29 31 alkanes show contributions from petrogenic sources n c28 30 fatty acids likely provide better estimates of average terrestrial residence times of vascular plant biomarkers moreover sedimentary n c28 and n c30 fatty acids appear clearly much less influenced by autochthonous sources than n c24 and n c26 fatty acids as indicated by increasing radiocarbon ages with increasing chain length and are thus more representative as vascular plant biomarkers

composition and fate of terrigenous organic matter along the arctic land ocean continuum in east siberia insights from biomarkers and carbon isotopes abstract climate warming is predicted to translocate terrigenous organic carbon terroc to the arctic ocean and affect the marine biogeochemistry at high latitudes the magnitude of this translocation is currently unknown so is the climate response the fate of the remobilized terroc across the arctic shelves represents an unconstrained component of this feedback the present study investigated the fate of permafrost carbon along the land ocean continuum by characterizing the terroc composition in three different terrestrial carbon pools from siberian permafrost surface organic rich horizon mineral soil active layer and ice complex deposit and marine sediments collected on the extensive east siberian arctic shelf esas high levels of lignin phenols and cutin acids were measured in all terrestrial samples analyzed indicating that these compounds can be used to trace the heterogeneous terrigenous material entering the arctic ocean in esas sediments comparison of these terrigenous biomarkers with other terroc proxies bulk 13c 14c and hmw lipid biomarkers highlighted contrasting across shelf trends these differences could indicate that terroc in the esas is made up of several pools that exhibit contrasting reactivity toward oxidation during the transport in this reactive spectrum lignin is the most reactive decreasing up to three orders of magnitude from the inner to the outer shelf while the decrease of hmw wax lipid biomarkers was considerably less pronounced alternatively degradation might be negligible while sediment sorting during the across shelf transport could be the major physical forcing that redistributes different terroc pools characterized by different matrix association despite the marked decrease shown by lignin the fingerprint of lignin phenols such as the acid aldehyde ratio of vanillyl and syringyl phenols showed a lack of any across shelf trends and exhibited an extremely wide range of values in all terrestrial samples by contrast the 3 5 dihydroxybenzoic vanillyl phenols ratio exhibited a clear across shelf trend suggesting either increasing degradation with distance from the coast or terroc sorting along the sediment dispersal system the ratio of syringyl vanillyl phenols indicated that gymnosperm tissues are more important than angiosperm tissues in surface sediments in particular off the lena river mouth consistent with the vegetation in its watershed conversely the fingerprint of p hydroxybenzenes suggests lack of substantial input of moss derived material finally autochthonous lipid and protein derived cuo reaction products displayed a strong along shelf gradient likely reflecting the inflow of nutrient rich pacific waters from the bering strait that stimulate primary productivity in the eastern esas in particular short chain fatty acids showed a clear frontal transition zone between pacific influenced and river influenced waters approximately along the 160 e longitude considering the labile nature of phytoplankton priming and co metabolism processes might stimulate degradation of terroc in the easternmost region of the siberian shelf this study demonstrated the need to consider multiple terroc proxies at isotopic molecular levels to differentiate the fate for different allocthonous components in arctic sediments and the need to assess how these terroc pools are distributed in different density size and settling fractions to better discriminate between the extent of hydrodynamic sorting versus degradation

distributions of branched gdgts in a tropical lake system implications for lacustrine application of the mbt cbt paleoproxy branched glycerol dialkyl glycerol tetraether gdgt lipids are abundant and ubiquitous in lake sediments potentially allowing for a paleolimnological application of the so called mbt cbt proxy methylation index of branched tetraethers cyclization ratio of branched tetraethers to investigate the origin and characteristics of these compounds in lacustrine environments we examined the distributions of gdgts in soils river sediments and lake sediments from lake towuti on the island of sulawesi indonesia we found significant differences in the degree of methylation and cyclization expressed by way of the mbt and cbt indices between the soil samples and the aquatic samples suggesting that there may be in situ production of gdgts in the aquatic environment based on these findings we urge caution in the application of the mbt cbt paleoproxy to lake sediments and encourage more rigorous study of these compounds in freshwater environments

distribution of hopanoids along a land to sea transect implications for microbial ecology and the use of hopanoids in environmental studies bacteriohopanepolyols bhps are lipid constituents of diverse bacteria and have great potential as taxonomically and environmentally diagnostic biomarkers in order to examine their environmental behavior and potential for tracing biogeochemical processes we analyzed bhps and geohopanoids the diagenetic products of bhps in soils and surface sediments from the middle yangtze river catchment to the east china sea ecs shelf these data are compared to an up to date survey of bhp distributions in soils including regions collectively covering the arctic temperate subtropics and tropics regional climatic differences particularly temperature likely exert an important control on bhp distributions in soils in the aquatic river estuary shelf setting bhp concentrations and structural diversity are substantially lower than in soils suggesting that in aquatic environments either bacterial biodiversity is lower or there is not the same requirement for hopanoid synthesis however different aquatic regimes vary substantially high bhp diversity and enhanced bhp production occur in the biogeochemically dynamic yangtze estuary whereas bhp distribution is uniform with much less structural diversity in the oligotrophic ecs open shelf the rsoil index based on the relative abundances of soil marker bhps against bacteriohopanetetrol is suggested as a new approach to trace soil organic matter input into marine sediments the rsoil indices decrease from the river to the ecs correlating strongly with branched and isoprenoid tetraether indices and moderately correlating with 13c of organic carbon values and the concentrations of higher plant biomarkers demonstrating their ability to trace soil organic matter inputs at least to the ecs

coal geology and coal quality of the miocene mugla basin southwestern anatolia turkey abstract this work focuses on the relationship between the coal geology and coal quality of the miocene mugla basin southwestern anatolia turkey to this end detailed petrographical mineralogical and geochemical studies were performed on composite profile samples from the nine coal fields in the mugla basin alatepe bagyaka bayir cakiralan ekizkoy eskihisar husamlar sekkoy and tinaz coal fields the mugla lignite is a high ash from 16 to 56 and sulphur from 2 1 to 5 7 lignite which is petrographically characterised by a high huminite content mainly gelinite macerals the mineral matter of the studied lignite samples is made up mainly of clay minerals and quartz with the exception of the sekkoy and ekizkoy lignites in which calcite is the dominant mineral phase with minor amounts of quartz clay minerals pyrite and gypsum and traces of aragonite syngenetic opal is also frequently identified in these samples the differentiation of these two types of lignite with specific mineralogical patterns is attributed to the contemporaneous development of peatlands with a high detrital input dominated by the quartz and clay mineral setting and peatlands with low detrital supply and a dominant carbonate rich lacustrine environment the higher water table of the latter allowed the precipitation of micritic carbonates and the development of lakes with abundant mollusc fauna this differentiation is also evidenced by the geochemical data thus the sekkoy ekizkoy husamlar bayir and alatepe lignites are characterised by relatively low al and fe contents

some considerations concerning the use of correlation coefficients and cluster analysis in interpreting coal geochemistry data the mode of occurrence of trace elements in coal is important from both scientific and environmental viewpoints because the behavior of trace elements in coal utilization depends not only on their concentration but also on their chemical form or mode of occurrence statistical methods are one of the more commonly used indirect approaches for interpreting element modes of occurrence these methods include correlation coefficients between elements and ash as well among the elements themselves cluster and factor analysis using data sets derived from a suite of 75 samples from a bulgarian lignite deposit we demonstrate that statistical analysis of subsets with different ash ranges and with slightly different suites of elements can lead to substantially different conclusions concerning the element modes of occurrence in this example we assume that direct information on the element modes of occurrence such as mineralogy or selective leaching behavior is absent statistical methods however can provide useful insights into trace element modes of occurrence for properly constrained sample suites

recent sediment accumulation and carbon burial in the east china sea 1 sediment and carbon budgets were constructed for the east china sea ecs shelf based on up to date data the total annual sediment flux in the ecs shelf is approximately 96 of the terrestrial input there is high retention of sediment on the ecs shelf owing to the broad nature of the shelf edge i e 500 600 km and because of an along shore sediment dispersal path driven by the east china sea coastal current ecscc and the taiwan warm current twc organic carbon oc burial was also observed based on the results for sediment accumulation and the oc proportion in surface sediment a total of 7 4 106 t of oc is preserved in shelf sediments source discrimination of sedimentary oc revealed that the percentage of oc burial for both terrigenous and marine oc sources was higher than the global mean value at 10 and 5 5 respectively presumably owing to high sediment accumulation high oc flux to sediment in the estuary and shelf break suggests that riverine discharge and upwelling of the kuroshio intrusion are key factors regulating oc burial over the shelf estimated using a mass balance model 15 20 of the carbon inventory is buried in the shelf sediment while 80 of the carbon inventory must be transported out of shelf area in the form of dissolved carbon organic and inorganic the accumulation of carbon in sediments and the outflow of dissolved carbon sustain a high carbon sink in the ecs

geological controls on the coal quality of the mequinenza subbituminous coal deposit northeast spain abstract the results of geological petrographical geochemical and mineralogical studies performed to determine the coal forming paleo environmental conditions which gave rise to anomalous enrichments in organic sulphur molybdenum and uranium in the oligocene mequinenza subbituminous coal deposit of northeastern spain are summarized this paper demonstrates the major influence exerted by the paleohydrology of the depositional framework on the early diagenetic evolution of the precursor peat deposits the s mo and u enrichments the preservation of aragonite and chlorophillinite and the high degree of gelification of the mequinenza coal are a consequence of alkaline syngenetic conditions in the depositional environment similar conditions can be inferred for many mesozoic and tertiary coal deposits in the mediterranean region mallorca sardinia hungary bulgaria serbia greece and turkey however the source of sulphur may have been different and have included triassic and early jurassic sulphate recycling scenarios or volcanic sources whatever the source sulphur enrichment is always influenced by the alkaline depositional environments developed in basins generated during the alpine cycle in circum mediterranean mobile belts

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

sources of sedimentary organic matter in the mississippi river and adjacent gulf of mexico as revealed by lipid biomarker and δ13ctoc analyses abstract changes in the organic matter om composition c n 13 c toc and lipid biomarker compounds of surface sediments 0 1 cm were examined along the dispersal pathway from mississippi river and marsh estuarine end members to the adjacent shelf and canyon regions of the gulf of mexico organic carbon content decreased fourfold from the marsh to the offshore sites with corresponding changes in organic matter sources biomarkers representing allochthonous higher plant and autochthonous algal plankton bacteria sources demonstrated regional differences in the sources of sediment organic matter som a two end member mixing model using 13 c toc indicated that c 3 vascular plant sources comprised 80 and 50 of the toc at the river and marsh sites respectively however sources of som differed in these regions with contributions of soil organic matter terrigenous plant sources dominant in the river 13 c toc 25 while marsh plants likely contributed to the enriched signatures found in the marsh sediments 13 c toc 18 allochthonous om contributions calculated from fatty acid and sterol biomarkers in the river and marsh regions 39 48 and 50 72 respectively differed from those determined using 13 c toc this was likely due to overlapping 13 c toc values for vascular plants and freshwater microalgae and the higher lipid content of the autochthonous sources although biomarkers representing terrigenous sources decreased with distance offshore they comprised approximately 17 34 of the fatty acid and sterols at even the most distal slope and canyon sites suggesting that these deeper regions could be an important sink for terrigenous carbon in contrast the shelf sites were enriched in algal material 60 78 autochthonous oc with biomarkers for diatoms dominating suggesting that terrigenous carbon is either diluted in or bypasses this region results from this study suggest that processes including hydrodynamic sorting diagenesis and variations in river flow should be considered in future studies investigating the fate of terrigenous om in coastal and shelf regions

tracing the evolution and distribution of f and cl in plutonic systems from volatile bearing minerals a case study from the liujiawa pluton dabie orogen china fluorine and chlorine play an important role in magmatic differentiation hydrothermal alteration and related mineralization processes but tracing their evolution in magmatic and especially plutonic systems is not an easy task the f and cl in melts can be estimated from f and cl concentrations in minerals provided that partitioning between minerals and melts are constrained based on available partitioning models between mineral melt mineral fluid and melt fluid a set of equations has been derived to determine f and cl concentrations in melts from the compositions of amphibole biotite and apatite the new calculation procedure has been applied to a plutonic system the liujiawa pluton eastern dabie orogen china cl and f concentrations in amphiboles biotites and apatites from different rock types gabbronorite two pyroxene diorite clinopyroxene diorite and hornblende gabbro have been determined by electron microprobe most amphiboles show a negative correlation between log cl oh and mg number and a positive correlation between log f oh and a site occupation biotites from the gabbronorite and two pyroxene diorite show a slight positive correlation between log cl oh and mg which is however not the case for the clinopyroxene diorite apatites from all the samples are rich in f and show negative correlations between cl and f concentrations in our case study we demonstrate that the cl concentration in melt remains approximately constant at 1 000 2 000 ppm over the major crystallization interval but decreases strongly at near solidus temperatures as a result of fluid exsolution the f concentration in melt remains nearly constant at ca 2 000 3 000 ppm at high temperatures as well as near solidus conditions indicating that it is not largely affected by fluid exsolution because of its strongly preferred incorporation into melt interestingly the evolution of cl and f concentrations in melt with magmatic differentiation is similar to that determined in volcanic systems suggesting that the evolution of cl and f in melts during crystallization and late magmatic stages at depth plutonic systems is similar to that observed in volcanic systems during decompression and degassing

organic matter distribution in the modern sediments of the pearl river estuary we determined biomarker concentrations and distributions for surface sediments from 54 sites in the pearl river estuary china we focus on a suite of four biomarker based indicators for relative terrestrial to marine organic matter om source the branched isoprenoid tetraether bit index the ratio of high low molecular weight n alcohols c26 34 c16 18 c26 34 an analogous ratio for n fatty acids and the c29 steroids c29 steroids brassicasterol ratio all four exhibit the same terrestrial to marine transition seen in previous bulk 13c studies but with an abrupt decrease in the relative terrestrial contribution across the delta front to pro delta transition concentrations of terrestrially derived biomarkers show no systematic decrease across the transition instead the decrease in the proportion of terrestrial om is due to a decrease in the sedimentation rate and associated terrestrial om burial across the delta toe this suggests that diagenetic controls on the fate of terrestrial om such as increased biodegradation where sedimentation rate is low are subordinate to sedimentological processes biomarker derived temperature values are cooler than expected for the lower pearl river catchment suggesting that the dominant component of the terrestrial om is derived from the cooler upland regions of the catchment the dominance of input from more distal terrain with greater topographic relief is evidence for the importance of geomorphological control on terrigenous om transport collectively the results demonstrate the importance of sedimentological processes in the supply deposition and transport of terrestrial om

tracing soil organic carbon in the lower amazon river and its tributaries using gdgt distributions and bulk organic matter properties abstract in order to trace the transport of soil organic carbon oc in the lower amazon basin we investigated the distributions of crenarchaeol and branched glycerol dialkyl glycerol tetraethers gdgts by analyzing riverbed sediments and river suspended particulate matter spm collected in the solimoes amazon river mainstem and its tributaries the branched and isoprenoid tetraether bit index a proxy for river transported soil oc into the ocean was determined from the distributions of these gdgts the gdgt derived parameters were compared with other bulk geochemical data i e c n ratio and stable carbon isotopic composition the gdgt derived and bulk geochemical data indicate that riverine spm and riverbed sediments in the lower amazon river and its tributaries are a mixture of c3 plant derived soil oc and aquatic derived oc the branched gdgts in the spm and riverbed sediments did not predominantly originate from the high andes soils 2500 m in altitude as was suggested previously however further constraint on the soil source area of branched gdgts was hampered due to the deficiency of soil data from the lower montane forest areas in the andes our study also revealed seasonal and interannual variation in gdgt composition as well as soil oc discharge which was closely related to the hydrological cycle by way of a simple binary mixing model using the flux weighted bit values at obidos the last gauging station in the amazon river we estimated that 70 80 of the poc pool in the river was derived of soil oc however care should be taken to use the bit index since it showed a non conservative behaviour along the river continuum due to the aquatic production of crenarchaeol further investigation using a continuous sampling strategy following the full hydrological cycle is required to fully understand how soil derived gdgt signals are transformed in large tropical river systems through their transport pathway to the ocean

terrestrial organic carbon contributions to sediments on the washington margin elemental and stable carbon isotopic compositions and biomarker concentrations were determined in sediments from the columbia river basin and the washington margin in order to evaluate geochemical approaches for quantifying terrestrial organic matter in marine sediments the biomarkers include an homologous series of long chain n alkanes derived from the surface waxes of higher plants phenolic and hydroxyalkanoic compounds produced by cuo oxidation of two major vascular plant biopolymers lignin and cutin all marine sediments including samples collected from the most remote sites in cascadia basin showed organic geochemical evidence for the presence of terrestrial organic carbon using endmember values for the various biomarkers determined empirically by two independent means we estimate that the terrestrial contribution to the washington margin is 60 for shelf sediments 30 for slope sediments and decreases further to 15 in basin sediments results from the same geochemical measurements made with depth in gravity core 6705 7 from cascadia seachannel suggest that our approach to assess terrestrial organic carbon contributions to contemporary deposits on the washington margin can be applied to the study of sediments depositing in this region since the last glacial period

sources of terrigenous inputs to surface sediments of the colville river delta and simpson s lagoon beaufort sea alaska 1 the provenance of sediments and particulate organic carbon poc in the colville river delta and adjacent simpson s lagoon in the alaskan beaufort sea was investigated using a variety of bulk and molecular techniques including stable and radiocarbon isotopes neodymium isotopes algal pigments and lignin phenols additionally stable carbon isotopes and lignin phenols were analyzed on four different density fractions from sediments the colville river the largest river in north america with a watershed exclusively located in the high arctic tundra was an important source of terrestrial poc to the western edge of the lagoon shown by extremely old radiocarbon ages fraction modern of 0 165 0 001 close to the river mouth up to 0 418 0 002 farther away stations without northern protective barrier islands had large amounts of marine poc input and evidence of benthic microalgae was found in one area of the lagoon chlorophyll a concentration 35 0 g goc 1 in the high algal biomass area compared to 1 to 7 g goc 1 outside of it stations in the middle and eastern end of the lagoon showed significant sediment input from coastal erosion input of peat indicating non lignin phenols 0 079 mg 100mgoc 1 in the eastern lagoon compared to 0 022 mg 100mgoc 1 near the colville delta and on the eastern end of the lagoon there was evidence of input of mackenzie river poc shown with neodymium isotopes and also cop poc inputs derived from rivers coastal erosion and marine productivity were quantified using a ternary mixing model and showed that fluvial supply and coastal erosion were the dominant carbon sources to the lagoon this constitutes the first study of poc delivery by the colville river into a nearshore region and illustrates that continued warming of the high arctic tundra will likely lead to increased riverine poc delivery to this region of the world

selective preservation of soil organic matter in oxidized marine sediments madeira abyssal plain in ocean margin sediments both marine and terrestrial organic matter om are buried but the factors governing their relative preservation and degradation are not well understood in this study we analysed the degree of preservation of marine isoprenoidal and soil derived branched glycerol dialkyl glycerol tetraethers gdgts upon long term oxygen exposure in om rich turbidites from the madeira abyssal plain by analyzing gdgt concentrations across oxidation fronts relative to the anoxic part of the turbidites ca 7 20 of the soil derived branched gdgts were preserved in the oxidized part while only 0 2 3 of the marine isoprenoid gdgt crenarchaeol was preserved due to these different preservation factors the branched isoprenoid tetraether bit index a ratio between crenarchaeol and the major branched gdgts that is used as a tracer for soil derived organic matter substantially increases from 0 02 to 0 4 split flow thin cell splitt separation of turbidite sediments showed that the enhanced preservation of soil derived carbon was a general phenomenon across the fine particle size ranges 38 m calculations reveal that despite their relatively similar chemical structures degradation rates of crenarchaeol are 2 fold higher than those of soil derived branched gdgts suggesting preferential soil om preservation possibly due to matrix protection

spatial and temporal variability in vegetation and coal facies as reflected by organic petrological and geochemical data in the middle miocene cayirhan coal field turkey abstract coal channel samples of middle miocene age are collected from the first tv and second tb seams from underground mines and from exploration boreholes within the cayirhan coal field in the beypazari basin turkey they are investigated in order to detect spatial and temporal changes in maceral and molecular composition of coal and to relate them to changes in vegetation and depositional environment the mean random reflectance values of ulminite 0 40 rr indicate a lignite to subbituminous c coal in rank maceral composition and biomarker ratios of the samples from both seams at the cayirhan deposit argue for coal formation in a limno telmatic environment under dysoxic to anoxic conditions alkaline surface waters of changing ph values and a high and unstable water level at the palaeomire are evidenced by moderate to high gelification index gi and ground water influence gwi values as well as high sulphur contents variations in tissue preservation index tpi and vegetation index vi values point to minor variations in the palaeovegetation during peat formation herbaceous plants dominated in both tb and tv palaeomires low tpi and vi values whereas in the surroundings arboreal vegetation were predominant the decreasing trends in pristane phytane ratios and carbon preference index cpi values towards the ne are suggested to reflect oxygen deficient conditions during peat formation due to a higher ground water level in this part of the basin the occurrence of c 29 diasterenes in low abundances provides evidence for periods of lower ph in the mire the borehole samples from the ne show slightly enhanced contributions of n alkanes from algal and microbial sources the terpenoid hydrocarbons present in the lignite argue for a major contribution of angiosperms to peat formation and slightly enhanced proportions of gymnosperms in the tv palaeomire in the ne based on the high concentrations of lupane type triterpenoids in the coal seams from the underground mine a higher density of betulaceae in the arboreal vegetation in the sw is indicated

pyroclastic kaolin coal tonsteins of the upper carboniferous of zonguldak and amasra turkey abstract the existence of pyroclastic kaolin coal tonsteins tonsteins smectites from upper carboniferous strata of the coal mining region of zonguldak and amasra north western turkey is reported in the area of zonguldak tonsteins were discovered within the seams pic ii and piric asma 5 mine of the kozlu formation westphalian a in the area of amasra tonsteins occur in the seams kalin and tavan tarlaagzi mine of the karadon formation westphalian b c thin sections were prepared to investigate mineral composition and texture detailed descriptions are presented kaolinite is the predominant mineral in the tavan tonstein montmorillonite illite is also present pyrogenic phenocrysts prove that the tonsteins are alteration products of volcanic ashes therefore a wide lateral distribution of these layers can be expected these tonsteins represent very suitable stratigraphic markers in the upper carboniferous strata of northwestern turkey

mechanistic controls on diverse fates of terrestrial organic components in the east china sea terrestrial carbon transferred from the land to sea is a critical component of the global carbon cycle a range of geochemical proxies has been developed to fingerprint the fate of terrestrial organic matter tom in marine sediments however discrepancies among different proxies limit our ability to quantify and interpret the terrestrial signals in marine sediments with consequences for the investigation of both the modern carbon cycle and past environmental change to mechanistically understand these discrepancies we examined the distributions of a range of terrestrial proxies and their aquatic counterparts i e marine proxies in the yangtze river east china sea yr ecs shelf system where tom experiences extensive modification during transport and burial tom proxies in the yr ecs system collectively fit a power law model but with distinct attenuation rates the a values for individual molecular proxy groups among a range of tom proxies the modeled a values decrease in the order soil marker bhps triterpenols lignin hmw n alkanols branched gdgts hmw n alkanes for biomarkers and rsoil bit tomiso for proxies tracing tom rapid loss of tom components through dissociation in the narrow estuary followed by oxidation over the wide open shelf are best described by power curves inherent chemical reactivity i e the number of functional groups responses to hydraulic sorting and in situ production regulate the individual attenuation rates of them chemical reactivity plays the most important role on proxy behavior supported by a strong correlation between a values and standard molal gibbs energies both physical protection and chemical reactivity fundamentally control the overall behavior of tom components with the relative importance being setting dependant the former is relatively important in the estuary whereas the later is the primary control over the open shelf moreover regional variation of different marine counterparts is also significant over the river ecs shelf system seemingly regulated by regional nutrient distributions therefore for tom estimates using molecular ratio approaches the specific behavior of individual terrestrial components and marine counterparts and the physical biological and chemical characteristics of depositional settings all need to be considered

whole coal versus ash basis in coal geochemistry a mathematical approach to consistent interpretations abstract several standard methods require coal to be ashed prior to geochemical analysis researchers however are commonly interested in the compositional nature of the whole coal not its ash coal geochemical data for any given sample can therefore be reported in the ash basis on which it is analyzed or the whole coal basis to which the ash basis data are back calculated basic univariate mean variance distribution etc and bivariate correlation coefficients etc measures of the same suite of samples can be very different depending which reporting basis the researcher uses these differences are not real but an artifact resulting from the compositional nature of most geochemical data the technical term for this artifact is subcompositional incoherence since compositional data are forced to a constant sum such as 100 or 1 000 000 ppm they possess curvilinear properties which make the euclidean principles on which most statistical tests rely inappropriate leading to erroneous results applying the isometric logratio ilr transformation to compositional data allows them to be represented in euclidean space and evaluated using traditional tests without fear of producing mathematically inconsistent results when applied to coal geochemical data the issues related to differences between the two reporting bases are resolved as demonstrated in this paper using major oxide and trace metal data from the pennsylvanian age pond creek coal of eastern kentucky usa following ilr transformation univariate statistics such as mean and variance still differ between the ash basis and whole coal basis but in predictable and calculated manners further the stability between two different components a bivariate measure is identical regardless of the reporting basis the application of ilr transformations addresses both the erroneous results of euclidean based measurements on compositional data as well as the inconsistencies observed on coal geochemical data reported on different bases

the remineralization of sedimentary organic carbon in different sedimentary regimes of the yellow and east china seas abstract we investigated the remineralization of sedimentary organic carbon soc at 12 sites in east china sea mobile muds ecsmms and south yellow sea central mud deposits sysmds using a time sequence sediment incubation experiment we examined pore water dissolved inorganic carbon dic dissolved organic carbon doc fluorescent dissolved organic matter fdom dissolved inorganic nitrogen din nutrients nh4 no3 and no2 redox sensitive elements fe2 and mn2 and major anions so42 and cl in incubated sediments to better constrain controlling mechanisms of soc remineralization under different sedimentary regimes lower dic production rates in sysmds 2 36 3 13 mmol m 2 d 1 than those in ecsmms 2 94 13 5 mmol m 2 d 1 were mainly attributed to cold bottom water masses and a relatively stable sedimentary environment in sys higher dic production rates were observed mostly at offshore sites of ecsmms that had relatively enriched 13c of soc which indicated preferential degradation of labile soc of marine origin when compared with tropical mobile muds higher bottom water temperatures thicker mobile muds and large inputs of reactive terrestrial oc resulted in more intense remineralization of soc in amazon mobile muds than in ecsmms lower ratios of doc dic production rates in ecsmms 0 11 0 72 were likely indicative of efficient transformation of oc and largely due to sulfate reduction a rapid increase in marine protein like fdom components during the incubation indicated that less stable marine soc was preferentially converted to doc and then to dic our soc budget indicates that 16 8 of soc was decomposed in sediments of ecsmms but only about 5 4 of soc was decomposed in sysmds suggesting lower soc preservation efficiency in mobile muds than distal muds

soil organic matter transport along an sub arctic river sea transect bacteriohopanepolyols bhps and glycerol dialkyl glycerol tetraethers gdgts have potential as soil tracing biomarkers for the extensive shelves of the arctic ocean in this work these biomarkers

diagenetic state and source characterization of marine sediments from the inner continental shelf of the gulf of cadiz sw spain constrained by terrigenous biomarkers surface sediments from the gulf of cadiz goc were analyzed by alkaline cuo oxidation in order to estimate the contribution of terrigenous organic matter tom to the inner continental shelf of the southwest iberian peninsula the parallel analysis of sediment samples from the two most important rivers draining to this coastal area i e guadiana river and tinto odiel fluvial system provided fundamental information regarding local terrestrial sources relatively constant intensive lignin parameters s v 1 0 0 1 and c v 0 22 0 04 and high values of the lignin phenol vegetation index lpvi 155 43 indicated that non woody angiosperm tissues constitute the dominant component of vascular plant material reaching the shelf sediments the nw to se decreasing isotopic 13 c and molecular k8 signatures found among the sediments coinciding with the guadiana delivery plume suggest that this river is the main terrestrial source in the inner goc shelf slightly elevated values of degradation indicative ratios ad al v 0 41 0 10 ad al s 0 34 0 07 3 5 bd v 0 14 0 05 p v s 0 24 0 09 suggested the alteration state of the shelf sediments the two fold higher ratios of the river sediments guadiana ad al v 0 82 0 08 ad al s 0 84 0 03 tinto odiel ad al v 0 86 0 12 ad al s 0 83 0 013 and the increasing degradation trend observed outward in the shelf lead us to consider preferential sorption processes instead of in situ diagenesis to affect the degradation signature of the shelf sediments preferentially solubilized degraded om is more likely to be sorbed and stabilized prior to transport to the marine system showing an apparently more advanced degradation state the use of the 3 5 bd v ratio in conjunction with ad al v revealed a composition continuum of the sedimentary om ranging from fresh plant materials to highly altered soil humic constituents elemental and molecular analyses show a land to sea gradient by a nw to se decrease of the terrestrial influence accounting for larger terrestrial inputs tom 71 98 in those sediments near the guadiana mouth and predominantly autochthonous composition tom 42 50 in those located offshore this work utilizes lignin derived biomarkers to determine the contribution of terrigenous om delivered to this poorly described coastal area from regional rivers within a context of increasing international efforts to better understand the global c cycling this study illustrates the relevance of using the alkaline cuo oxidation approach to evaluate c budgets and continental influence in river dominated ocean margins 2008 elsevier ltd all rights reserved

tuffaceous deposition in the newcastle coal measures challenging existing concepts of peat formation in the sydney basin new south wales australia abstract the late permian newcastle coal measures of the northern sydney basin australia contain numerous volcanic ash deposits occurring as both interseam tuffs and intraseam tonsteins these tuffaceous units have been used to correlate seams of the newcastle coal measures with the stratigraphically equivalent wollombi coal measures in the adjacent hunter coalfield such correlations across the width of the northern sydney basin are based not on only tuffaceous markers but also on chemical and maceral profiles within individual coal plies and carbonaceous shales these correlations imply a lateral continuity of the peat forming environment previously unrecognised in the sydney basin and have led directly to the discovery of a new open cut coal resource in the hunter coalfield the uniform distribution of tonsteins and coal plies also challenges many existing concepts of peat formation it is proposed that the peat surface was predominantly below the water table and the term lowered mire is proposed to describe this environment a subaqueous peat surface would protect thin volcanic ash deposits from subsequent redistribution by rainfall and surface runoff and is consistent with a lack of tree preservation within the intraseam tonsteins it is envisaged that trees were generally restricted to the peat margins and to specific horizons where the peat surface was exposed by a fall in the water table long distance correlations of tonsteins also contradict models of coal formation incorporating lateral peat migration where time constant horizons such as tonsteins should transgress the coal seam profile over large distances

a multiproxy analysis of sedimentary organic carbon in the changjiang estuary and adjacent shelf surface sediments from the changjiang estuary and adjacent shelf were analyzed using a variety of bulk and molecular techniques including grain size composition sediment surface area ssa elemental composition c n stable carbon isotopic composition 13c n alkanes lignin phenols and glycerol dialkyl glycerol tetraether lipids to obtain a more comprehensive understanding of the sources and fate of sedimentary organic carbon soc in this dynamic region bulk n c ratios of 0 09 to 0 15 13c of 24 4 to 21 1 branched isoprenoid tetraether index of 0 to 0 74 n alkane content of 0 02 to 0 37 mg g 1 organic carbon oc and lignin content 8 of 0 10 to 1 46 mg 100 mg oc and other related molecular indices in these samples indicate a mixed source of marine soil and terrestrial plant derived oc in the study area a three end member mixing model using principal component analysis pca factors as source markers and based on monte carlo mc simulation was constructed to estimate the relative contributions of oc from different sources compared with traditional mixing models commonly based on a few variables this newly developed pca mc model supported bulk and biomarker data and yielded a higher resolution oc inputs to different subregions of this system in particular the results showed that the average contributions of marine soil and terrestrial oc in the study area were 35 3 47 0 and 17 6 and the highest contribution from each oc source was mainly observed in the shelf inner estuary and coastal region respectively

organic matter sources transport degradation and preservation on a narrow rifted continental margin shoalhaven southeast australia abstract the continental delivery of fine grained siliciclastic sediment together with the composition of exported terrigenous organic matter om has a strong impact on the content and composition of sedimentary om accumulating on contemporary oxic continental shelf sediments the composition of terrigenous om appears to be in turn largely related to the geodynamic setting of the drained margin this study provides results from a comprehensive source to sink investigation along the shoalhaven river new south wales and its associated non deltaic deposits on the se australian continental margin a margin whose dimensions and morphology differ from those of standard passive margins the om content of 23 surface sediment samples collected along the river course estuary and adjacent continental shelf was investigated by integrating bulk om measurements such as total organic carbon content toc toc total n c n carbon stable isotope 13 c toc and radiocarbon content of toc 14 c toc with lipid biomarker analysis geochemical data were coupled with sediment particle size analysis the toc content correlated strongly with the clay silt content in all the environments confirming the importance of fine grained particles om association as an influential preservation factor a three component mixing model was used to show that om in continental shelf sediments consisted of 15 20 terrigenous biospheric om mostly modern plants 15 25 fossil c and marine om while such bimodal terrigenous input modern plants and fossil c is typical of active margins this study reinforces the paradigm that om residence times within major bioactive reservoirs during transfer in turn related to geomorphic characteristics strongly influence the composition of exported om

historical reconstruction of organic carbon decay and preservation in sediments on the east china sea shelf 1 sediment cores were collected from the east china sea inner shelf in 2010 to study the decay and preservation of organic carbon oc the highest sediment mass accumulation rate 0 61 0 20 g cm 2 yr 1 derived from 210pb was found near the river mouth and decreased alongshore to the south 0 17 0 004 g cm 2 yr 1 and in an offshore direction 0 31 0 08 g cm 2 yr 1 average total oc content was higher at inner shelf stations 0 52 than those offshore 0 38 the 13c was more depleted at nearshore 23 49 to 21 97 than offshore 22 49 to 21 60 stations principal component analysis indicated that terrestrial oc as indicated by lignin phenols 8 values was preserved in sediment closer to the coast 0 22 0 44 while offshore sediment was more composed of lignin poor 0 12 0 24 degraded oc that was likely hydrodynamically sorted marine derived oc as indicated by plant pigments was significantly more abundant in the sediment mixed layer than the underlying accumulation layer historical flooding events were detected in 8 profiles in two of the six cores located at midshelf stations despite the magnitude of the 2010 flood in east china we did not see any signature of this event with the chemical biomarker in these two cores this may suggest that reduced sediment loading due to recent dam construction may have greatly decoupled river inputs with sediment loading to shelf sediment the total oc standing stock since 1900 was approximately 1 62 1 15 kg c m 2 about one tenth of all the middle and lower lakes in the changjiang catchment basin this work further supports the need for more research to better understand how the reduced inputs of fluvial input of sediments from chinese rivers due to river diversions and dams affect carbon cycling in the east china sea

spatial variability in the abundance composition and age of organic matter in surficial sediments of the east china sea 1 understanding the sources and fate of organic matter om sequestered in continental margin sediments is of importance because the mode and efficiency of om burial impact the carbon cycle and the regulation of atmospheric co2 over long time scales we carried out molecular lignin derived phenols from cuo oxidation elemental isotopic 13c 14c and sedimentological grain size and mineral surface area analyses in order to examine spatial variability in the abundance source age of surface sediments of the east china sea higher terrigenous organic matter values were found in the main accumulating areas of fluvial sediments including the changjiang yangtze estuary and zhejiang fujian coastal zone isotopic and biomarker data suggest that the sedimentary om in the inner shelf region was dominated by aged 14c 423 42 but relatively lignin rich om 0 94 0 57 mg 100 mg oc associated with fine grained sediments suggesting important contributions from soils in contrast samples from the outer shelf while of similar age 14 c 450 99 are lignin poor 0 25 0 14 mg 100 mg oc and associated with coarse grained material regional variation of lignin phenols and om ages indicates that om content is fundamentally controlled by hydrodynamic sorting especially sediment redistribution and winnowing and in situ primary production selective sorption of acid to aldehyde in clay fraction also modified the ratios of lignin phenols the burial of lignin in east china sea is estimated to be relatively efficient possibly as a consequence of terrigenous om recalcitrance and or relatively high sedimentation rates in the changjiang estuary and the adjacent zhejing fujian mud belt

multiple sources and extensive degradation of terrestrial sedimentary organic matter across an energetic wide continental shelf the fate of organic carbon in marine sediments is closely linked to atmospheric co2 concentrations and thus to climate variability over geological time scales the east china sea ecs is characterized not only by massive terrestrial organic matter tom inputs from the yangtze changjiang river but also by a shallow 500 km continental shelf with widespread relict sands such that it is distinct from other continental margins we examine the diagenesis of sedimentary tom and the impacts of relict sands on tom in the ecs the results reveal that bulk 13corg values correlate with terrestrial biomarker concentrations in muddy and accumulative areas in contrast depleted 13corg values around 24 5 co occur with almost absent terrestrial biomarkers in sandy erosional areas we suggest that mixing of contemporary tom and marine om dominates in the muddy accumulative shelf areas whereas a putative relict om associated with relict sands appears to be significant in many sandy erosional shelf areas given the global occurrence of relict sands a persistent amount of relict oc e g 0 1 may complicate tom budget calculations in addition our observations reveal that tom is extensively partitioned and degraded in the estuary and continues to be partitioned and degraded during the along shore and across shelf transport which is reflected by decreases in terrestrial biomarker concentrations and increases in degradation indices this study highlights the unique and dynamic role of shallow and wide continental shelves with massive relict sands on tom cycling

environmental evolution of the east china sea inner shelf and its constraints on pyrite sulfur contents and isotopes since the last deglaciation abstract to better understand the depositional constraints on the sulfate reduction process we present a set of sulfur isotope data for hand picked pyrites 34spyr from the coarse fraction 63 250 m of bulk sediments coupled with the contents of carbonate total organic carbon toc and nitrogen tn as well as 13c values of the toc from sediments of core ec2005 on the inner shelf of the east china sea ecs since 16 4 ka our results show that core sediments were deposited in a terrestrial environment before 13 1 ka stage i when pyrite rarely occurred during stages ii 13 1 12 3 ka and iii 12 3 12 1 ka seawater began to influence the core location forming a tidal flat environment where abundant pyrites are well preserved then the inner shelf of the ecs was fully flooded and two intervals with high stage iv 12 1 6 0 ka stage vi 5 2 1 5 ka and low sedimentation rate stage v 6 0 5 2 stage vii 1 5 ka present are identified respectively when compared with previous 34s values of chromium reducible sulfur 34scrs derived from the bulk sediments 34spyr values are usually higher indicating the macroscopic pyrites form in the later stages of sedimentary diagenesis when ongoing sulfate reduction has distilled porewater sulfate to a high degree considering the wide occurrence of biogenic shallow gas dominated by ch4 in these sediments sulfate driven anaerobic oxidation of methane so4 aom and organoclastic sulfate reduction osr are expected to be two competitive pathways for sulfate reduction we propose that the changes in sedimentation rate controls the pace of migration of the sulfate methane transition zone smtz when sedimentation rate is low the smtz may be fixed in a certain depth e g sediments deposited in stage iii and v where h2s is produced by so4 aom in contrast when sedimentation rate is very high 1 cm yr the smtz would be deep and h2s is mostly produced by osr further our results imply that sulfur diagenesis in recent since 1 5 ka ecs mud sediments might be influenced by physical reworking e g typhoon and or biological activity bioturbation resulting in partial reoxidation of pyrite crystals in fluid mud our findings therefore demonstrate that pyrite sulfur isotope compositions bulk 34scrs hand picked 34spyr are sensitive to local environmental evolution and the combined use of these two indicators can provide new insights into pathway of sulfate reduction in unsteady environments

petrological geochemical and mineralogical compositions of the low ge coals from the shengli coalfield china a comparative study with ge rich coals and a formation model for coal hosted ge ore deposit abstract to better understand the formation mechanism of coal hosted ge ore deposits this paper reports on the petrological mineralogical and geochemical compositions of the low ge coals in the shengli coalfield inner mongolia china using optical microscopy field emission scanning electron microscopy x ray fluorescence x ray diffraction and inductively coupled plasma mass spectrometry the samples in the present study closely neighbor the previously reported wulantuga coal hosted ge ore deposit both no 6 coal in comparison with the wulantuga ge rich coals the low ge coals of the shengli field display higher moisture 27 59 on average and lower pyritic sulfur contents 0 53 both the low ge and ge rich coals are generally high in inertinite and have varying but relatively low huminite contents preservation of fecal pellets as macrinite is notable in both the low ge and ge rich coals and the position of the fecal pellets appears to be within tunnels or chambers within the wood quartz kaolinite pyrite and gypsum are the major crystalline phases identified in most of the ge rich and low ge coals but the low ge coals contain significantly less pyrite and are more abundant in non mineral ca and mg ca oxalate of authigenic origin is observed generally occurring as cell fillings in the low ge coals otherwise mineral free organic matter in the low ge coals would be expected to have an inherent ash yield of around 6 derived from the inorganic elements mainly non mineral ca and mg that occur either in the organic matter or as dissolved ions in the pore water and form the sulfate species in low temperature oxygen plasma ash residues the highly elevated trace elements including be ge as sb w hg and tl that occur in the ge rich coals of the wulantuga deposit are significantly depleted in the low ge coals lateral migration of ge w and as hg sb tl rich solutions through the original peat swamp for the wulantuga ge ore deposit has led to significant enrichment of ge on the margin of the coal basin but decreasing ge concentrations toward to the inner part of the basin such a migration direction is different to those in the previously reported for the hydrothermal solutions in the lincang yunnan of china and spetzugli russian far east ge ore deposits where the solutions migrated vertically from granite to peat along faults and led to a dome shaped ge distribution in the relevant coal seam

mineralogy of the volcanic influenced great northern coal seam in the sydney basin australia abstract the mineralogy of the individual coal plies and intra seam claystone bands in the great northern seam of the sydney basin has been evaluated using optical and scanning electron microscopy and quantitative x ray diffraction techniques the uppermost two claystone bands are tonsteins consisting mainly of well ordered kaolinite with graupen to vermicular textures idiomorphic crystals of k feldspar within these tonsteins may represent members of the anorthoclase sanidine series or a sodic sanidine and indicate an acid to intermediate volcanic ash input in contrast the lowermost parting was largely derived from epiclastic sediment admixed with minor volcanic material such as high temperature quartz and a different type of k feldspar component the mineral fraction of the coals especially in the middle and upper parts of the seam is dominated by authigenic kaolinite with a very low abundance of quartz apart from the tonsteins authigenic processes therefore appear to be the dominant mechanism of mineral matter formation authigenic k feldspar also occurs in the lower few metres of the seam with a variety of modes of occurrence including cell and cleat infillings cross cutting veins and thin laminae parallel to the organic matter and detrital clay bands a late syngenetic low temperature hydrothermal fluid injection process is suggested for formation of the feldspar veins the origin of the fluid is uncertain but is most likely associated with contemporaneous volcanic activity

sources and distribution of organic matter in a river dominated estuary winyah bay sc usa abstract the sources and distribution of organic matter om in surface waters and sediments from winyah bay south carolina usa were investigated using a variety of analytical techniques including elemental stable isotope and organic biomarker analyses several locations along the estuary salinity gradient were sampled during four different periods of contrasting river discharge and tidal range the dissolved organic carbon doc concentrations of surface waters ranged from 7 mg l 1 in the lower bay stations closest to the ocean to 20 mg l 1 in the river and upper bay samples there was a general linear relationship between doc concentrations and salinity in three of the four sampling periods in contrast particulate organic carbon poc concentrations were significantly lower 0 1 3 mg l 1 and showed no relationship with salinity the high molecular weight dissolved om hmw dom isolated from selected water samples collected along the bay displayed atomic carbon nitrogen ratios c n a and stable carbon isotopic compositions of organic carbon 13coc that ranged from 10 to 30 and from 28 to 25 respectively combined such compositions indicate that in most hmw dom samples the majority of the om originates from terrigenous sources with smaller contributions from riverine and estuarine phytoplankton in contrast the c n a ratios of particulate om pom samples varied significantly among the collection periods ranging from low values of 5 to high values of 20 overall the trends in c n a ratios indicated that algal sources of pom were most important during the early and late summer whereas terrigenous sources dominated in the winter and early spring in winyah bay bottom sediments the concentrations of the mineral associated om were positively correlated with sediment surface area the c n a ratios and 13coc compositions of the bulk sedimentary om ranged from 5 to 45 and from 28 to 23 respectively these compositions were consistent with predominant contributions of terrigenous sources and lesser but significant inputs of freshwater estuarine and marine phytoplankton the highest terrigenous contents were found in sediments from the river and upper bay sites with smaller contributions to the lower parts of the estuary the yields of lignin derived cuo oxidation products from winyah bay sediments indicated that the terrigenous om in these samples was composed of variable mixtures of relatively fresh vascular plant detritus and moderately altered soil om based on the lignin phenol compositions most of this material appeared to be derived from angiosperm and gymnosperm vascular plant sources similar to those found in the upland coastal forests in this region a few samples displayed lignin compositions that suggested a more significant contribution from marsh c3 grasses however there was no evidence of inputs of spartina alterniflora a c4 grass remains from the salt marshes that surround the lower sections of winyah bay

effects of long term oxic degradation on the u37k tex86 and bit organic proxies abstract one of the primary prerequisites for the application of organic proxies is that they should not be substantially affected by diagenesis however studies have shown that oxic degradation of biomarker lipids can affect their relative distribution we tested the diagenetic stability of the u 37 k and tex86 palaeothermometers upon long term oxygen exposure for this purpose we studied the distributions of alkenones and glycerol dialkyl glycerol tetraethers gdgts in different sections of turbidites at the madeira abyssal plain map that experienced different degrees of oxygen exposure sediments were deposited anoxically on the shelf and then transported by turbidity currents to the map which has oxic bottom water this resulted in partial degradation of the turbidite organic matter as a result of long term exposure to oxic bottom water concentrations of gdgts and alkenones were reduced by one to two orders of magnitude in the oxidized parts of the turbidites compared to the unoxidized parts indicating substantial degradation high resolution analysis of the pleistocene f turbidite showed that the u 37 k index of long chain alkenones increased only slightly 0 01 corresponding to u 37 k while for other pliocene miocene turbidites it either remained unchanged or decreased substantially up to 0 06 corresponding to 6 c previous observations showed that the bit index a proxy for the contribution of soil organic matter to total organic carbon was always substantially higher in the oxidized part in all the turbidites as a result of preferential degradation of marine derived gdgts this relative increase in soil derived gdgts affects tex86 as the isoprenoid gdgt distribution on the continent can be quite different from that in the marine environment our results indicate that the organic proxies are affected by long term oxic degradation to different extents this should be taken into account when applying these proxies in palaeoceanographic studies of sediments which have been exposed to prolonged oxic degradation

pyrite sulfur isotopes constrained by sedimentation rates evidence from sediments on the east china sea inner shelf since the late pleistocene abstract isotopic compositions of coeval sulfide and sulfate have been widely employed to reconstruct the seawater chemistry evolution over geologic time however these signals can be modulated by other factors such as the sedimentation rate here we present a data set of pyrite sulfur isotopes 34spy derived from 60 m drilled core sediments deposited on the inner shelf of the east china sea since 16 5 ka the resulting 34spy values range from 38 2 to 15 0 vienna canyon diablo troilite v cdt representing a range of 53 2 freshwater deposition before 12 3 ka produced a limited pyrite abundance and 34spy values that fall within the typical range of freshwater environments after the marine incursion in the study area at 12 3 ka variations in the 34spy values become significantly correlated with sedimentation rates srs r 0 78 p 0 suggesting that srs exert controls on 34spy values we propose that these sedimentary controls are expressed by modulating the connectivity between porewaters and the overlying seawater low srs tend to form an open diagenetic system in which the pyrites are able to preserve the large biological fractionations associated with microbial sulfate reduction and disproportionation in contrast high srs favour a restricted diagenetic system in which the distillation of porewater sulfate produces pyrites enriched in 34s masking the magnitude of biological fractionation during microbial sulfur cycling these findings highlight the critical effect of the local sedimentation regime on pyrite sulfur isotopic compositions especially within shallow depositional environments over geologic time

characterizing the depositional settings for sedimentary organic matter distributions in the lower yangtze river east china sea shelf system grain size distributions total organic carbon toc and total nitrogen tn concentrations and toc tn ratios c n were analysed for surface sediments from the lower yangtze river east china sea ecs shelf system hierarchical cluster analysis of grain size parameters mode mean sorting skewness and kurtosis has been employed to characterize grain size compositions the results suggest there are five grain size compositional types type i v that fingerprint distinct depositional conditions in areas with high sedimentation rates hydrological sorting preferentially enriches the fraction coarser than 6 4o 12 m in shallow seafloor sediments water depth 30 m and thus forms grain size compositional type i shallow and type ii deep in the open shelf where modern sediment supply is very limited grain size types iii v are identified according to different winnowing intensity overall toc contents significantly correlate with mud proportions suggesting muddy sediments are the primary control on om accumulation however de association of terrestrial om from fine sediments in the estuary and the occurrence of presumably relict om in the open shelf exert additional controls on om dispersal and carbon cycling in the ecs by considering geography oceanography sediment source and the relation between sedimentation conditions and sedimentary om distributions we define six depositional settings the lower river the estuary the coast the offshore upwelling area the erosional area and the open shelf these settings describe the sediment dispersal and associated organic matter cycling in the lower yangtze river ecs shelf system

magnetic properties of east china sea shelf sediments off the yangtze estuary influence of provenance and particle size abstract the east china sea continental shelf offshore from the yangtze river estuary is a sedimentary system characterized by complicated hydrodynamic conditions and large variability in sediment texture granulometric geochemical and environmental magnetic analyses were carried out on surface sediments from this area to investigate the spatial variations of sediment composition and their underlying mechanisms magnetic properties of three particle size fractions 63 m were further analyzed to assist data interpretation our results reveal four distinct units subaqueous yangtze delta and inner shelf mud deposits unit a relict sands on the middle shelf unit b the transitional environment between unit a and b unit c and the area northern to unit a unit d the distributions of organic carbon iron manganese and their ratios mn fe suggest minor effects of reductive diagenesis on the surface sediment magnetic properties because of differences in sediment source and hydrodynamic conditions sediments in unit a have the highest ferrimagnetic and antiferromagnetic mineral concentrations as well as the finest ferrimagnetic grain size the significant variations of magnetic properties within unit a indicate the effect of particle size sorting during sediment transportation and deposition sediments in unit b have the coarsest ferrimagnetic grain size and the highest proportion of ferrimagnetic versus antiferromagentic minerals unit c which has a bimodal size distribution can be subdivided into a southern and northern part magnetically reflecting the influence of provenance and particle size the distinct magnetic characteristics of unit d are probably due to the strong influence of materials from the yellow river our results provide a new method for characterizing east china sea shelf sediments offshore of the yangtze river mouth against which the extent of the influence of the yangtze river on the east china sea can be examined furthermore it may provide a baseline for future long term monitoring in this sensitive continental margin environment that is influenced by the yangtze river