character of transverse faults in the elat pull apart basin the elat deep is a large pull apart basin about 50 km long within the gulf of elat aqaba its southern end displays many details of the way in which a pull apart basin is terminated at one of its ends a marine geophysical study has revealed that the southern edge of the basin consists of a complicated deformed zone which contains several distinct active faults and faults which were recently active they strike at a large oblique angle to the long dimension of the elat deep most of the faults display dipslip offsets although a lateral slip component may also be present on some faults

late pleistocene extension and strike slip in the dead sea basin a newly discovered active small scale pull apart mor structure located in the western part of the dead sea basin shows recent basin parallel extension and strike slip faulting and offers a rare view of pull apart internal structure the mor structure is bounded by n s trending strike slip faults and cross cut by low angle e w trending normal faults the geometry of this pull apart suggests that displacement between the two stepped n s strike slip faults of the mor structure is transferred by the extension associated with the normal faults the continuing deformation in this structure is evident by the observation of at least three deformation episodes between 50 ka and present the calculated sinistral slip rate is 3 5 mm yr over the last 30 000 years this slip rate indicates that the mor structure overlies the currently most active strike slip fault within the western border of the dead sea pull apart the mor structure is an example of a small pull apart basin developed within a larger pull apart this type of hierarchy in pull apart structures is an indication for their ongoing evolution

evidence for preindustrial variations in the marine surface water carbonate system from coralline sponges 1 coralline sponge skeletons are excellent tools for reconstructing the carbon isotope history of dissolved inorganic carbon dic in tropical surface waters carbon isotope records from coralline sponges clearly reflect the industrial 12c increase in atmospheric co2 with a precision that permits quantitative interpretations we find from a set of 13c records of four caribbean sponge specimens that the isotopic response of surface water dic to the changing isotopic composition of atmospheric co2 varied dynamically during the last century depending on the rate of atmospheric change three of our sponges provide 600 year long 13c records for the first time we can reconstruct surface water 13cdic for the full history of the industrial co2 release as well as the preceding preindustrial period back to the beginning of the little ice age this provides a well founded estimate of the anthropogenically uninfluenced preindustrial background level of surface water 13c 12c ratios our records show small but systematic variations that appear to be linked to the climate fluctuations of the little ice age

three hundred year hydrological changes in a subtropical estuary rookery bay florida human impact versus natural variability the coastal wetland ecosystems in florida are highly sensitive to changes in freshwater budget which is driven by regional sea surface temperature tropical storm activity and the el nino southern oscillation enso although studying florida wetlands is pivotal to the understanding of these interacting climate systems wetland dynamics have been severely altered by recent land use and drainage activities to gather insights into the natural variability of the coastal ecosystems in florida versus the effects of anthropogenic impact in the area we present a 300 year record of changes in the hydrological cycle from a shallow subtropical estuary rookery bay on the western shelf of florida gulf of mexico palynological pollen and organic walled dinoflagellate cysts diatom and sedimentological analyses of a sediment core reveal significant changes in past runoff and wetland development the onset and development of human impact in florida are evident from high influx of ambrosia pollen at about a d 1900 indicative of land clearance and disturbed conditions to date this is the southernmost record of ambrosia increase related to human impact in the united states wetland drainage and deforestation since a d 1900 are evident from the reduced freshwater wetland and pine vegetation and lower abundances of phytoplankton species indicative of lagoonal and brackish conditions high runoff after a d 1900 relates to increased erosionand may correspondingly reflect higher impact from hurricane landfalls in sw florida several phases with high siliciclastic input and greater wetland pollen abundance occur that predate the human impact period these phases are interpreted as periods with higher runoff and are likely related to regional longer term climate variability copyright 2008 by the american geophysical union

the geochemistry of deep sea coral skeletons a review of vital effects and applications for palaeoceanography deep sea corals were discovered over a century ago but it is only over recent years that focused efforts have been made to explore the history of the oceans using the geochemistry of their skeletal remains they offer a promising archive of past oceanic environments given their global distribution layered growth patterns longevity and preservation as well as our ability to date them using radiometric techniques this paper provides an overview of the current state of the art in terms of geochemical approaches to using deep sea coral skeletons to explore the history of the ocean deep sea coral skeletons have a wide array of morphologies e g solitary cup corals branching colonial corals and materials calcite aragonite and proteins as such their biomineralization strategies are diverse leading to complex geochemistry within coral skeletons notwithstanding these complications progress has been made on developing methods for reconstructing the oceanographic environment in the past using trace elements and isotopic methods promising approaches within certain coral groups include clumped isotopes and mg li for temperature reconstructions boron isotopes and radiocarbon for carbon cycling end and radiocarbon for circulation studies and 15 n p ca and ba ca for nutrient tracer studies likewise there is now a range of techniques for dating deep sea corals skeletons e g u series radiocarbon and determining their growth rates e g radiocarbon and 210 pb dating studies on historic coral populations in the atlantic southern ocean and pacific point to climate and environmental changes being dominant controls on coral populations over millennial and orbital timescales this paper provides a review of a range of successes and promising approaches it also highlights areas in which further research would likely provide new insights into biomineralization palaeoceanography and distribution of past coral populations

structural framework of the gulf of elat aqaba northern red sea the gulf of elat aqaba occupies the southern part of the dead sea rift the rift is considered to be a plate boundary of the transform type partially leaky which connects seafloor spreading in the red sea with the sagros taurus zone of continental collision the deep water in the gulf of elat up to 1850 m provides a rare opportunity to examine the process of continental rifting by marine geophysical techniques the bathymetry alone provides much information about fault patterns in this area the fragmentation of the once continuous arabian african platform is a complicated process it shapes the structure of the gulf which has developed through continuing tectonism primarily consisting of faulting recent geophysical and geological studies of the gulf of elat including bathymetry bottom photographs continuous seismic profiles seismic refraction gravity magnetics heat flow and coring provide new information about the shallow and deep crustal structure of this important segment of the world rift system the shallow structure of the gulf is dominated by three elongated en echelon basins which strike n20 25 e undulations in the floors of the basins produce several distinct deeps these basins are interpreted as pullaparts the new data from the gulf suggest that classical models for the formation of these structures should be modified only one of the longitudinal faults of each depression is a strike slip fault while the other is predominantly a normal fault the situation with the other two sides of the basin which are supposed to be composed of normal faults may also be more complex than previously thought at least in one case one such boundary is composed of a strike slip fault while the other has no significant fault crustal models of the gulf of elat based on gravity data indicate that the basins are rather shallow and do not extend into the lower crust the fill of the basins extends to about 5 km below the seafloor in the northern and southern basins and less in the central basin most significant magnetic anomalies in the gulf of elat extend from land into the sea none of them however extends from one coast to another across the gulf this supports the geological evidence for a shear between the arabia and sinai plates the magnetic field over the southern third of the gulf is rather smooth and markedly different from that of the other parts the nature of the magnetics the crustal structure of the western margin and the heat flow values indicate a thinner crust and different tectonic processes in the southern part of the gulf overall it seems that within the southern gulf of elat a transition occurs between crustal spreading that takes place in the red sea to a rifting without spreading that takes place along the dead sea transform spreading activity propagates from south to north the most active place is the central basin which is being propagated northward into the shallow northern basin

a seismic refraction study of the north basin of the dead sea israel a seismic refraction experiment involving the use of 9 obs and 11 portable seismic land stations was conducted along a profile in the north basin of the dead sea the seismometers were deployed along a north south profile in the lake and the adjacent land area the interpretation of the recorded seismograms indicates the presence of two large pliocene salt diapirs in the young basin fill the basement lies at a relatively shallow depth 6 8 km under the north basin further south along the profile a major fault affecting the basement was detected the apparent sense of the faulting is down to the southeast representing the boundary of the south basin this major faulting with a downthrow of some 4 5 km has depressed the crystalline basement and the overlying cretaceous and pre cretaceous sediments the faulting was followed by the deposition of over 8 km of recent and tertiary sediments resulting in a 14 km thick sedimentary sequence in the south basin of the dead sea

paleomagnetism of the zambales ophiolite luzon northern philippines abstract paleomagnetic results are reported from 52 sites in the zambales ophiolite the sites provide vertical sampling from the overlying sediments in the north and south to layered gabbros and dunites in the acoje and coto mines in the west they extend over an area of approximately 100 by 50 km a late miocene pliocene intrusion in the tarlac region gives a direction marginally distinguishable from the present field indicating a small clockwise rotation this is consistent with other indications of clockwise rotation since late miocene in luzon early and mid miocene sediments from barlo in the north and tarlac in the south indicate a period of rapid counterclockwise rotation during the miocene again consistent with other results from luzon eocene oligocene sediments overlying the ophiolite in the north and south indicate further counterclockwise rotation with northerly translation the interpretation of the directions in the ophiolite itself is more problematical directions similar to those in the eocene oligocene and in mid miocene sediments probably reflect secondary magnetizations and magnetization associated with the unroofing of the ophiolite we interpret the most strongly counterclockwise rotated magnetizations represented by a 44 ma sill in the barlo area and of the 46 ma dykes at coto as the primary direction of the ophiolite the counterclockwise rotation and northward translation interpreted from our results is consistent with the holloway model of the origin of the philippines however this model neglects the role of the philippine sea plate in the tectonic history of the philippines the counterclockwise rotation is also consistent with rotation of luzon in the left lateral shear between the philippine sea plate and asia as suggested by sarewitz and karig our data do not distinguish between counterclockwise rotation of a single block or of a number of smaller blocks the data suggest post late miocene clockwise rotation for luzon when it was coupled to the philippine sea plate our data are not consistent with a philippine sea plate origin for zambales

acoustic reflectivity and shallow sedimentary structure in the sea of galilee jordan valley abstract mapping the floor of the sea of galilee lake kinneret with a shallow seismic system of 3 5 khz resulted in interesting data that were not obtained previously with standard single channel seismic systems over most of the lake acoustic penetration is not possible probably because of the high gas content in the top sedimentary sequence however in a few areas excellent penetration of about 20 m was achieved one area is a terrace in the southern part of the lake south of a small bathymetric escarpment at depths of 13 21 m along israel latitudinal grid 238 it is unclear whether the existence of gas in the sediment or other parameters are responsible for the marked difference in acoustic penetration on both sides of the scarp another area with acoustic penetration is in the vicinity of hot and salty submarine springs although there is no difference in the composition of the upper sedimentary layers between these areas and neighbouring areas there is a marked difference in the acoustic penetration the contact between areas with acoustic penetration to areas without acoustic penetration is very sharp the craters of the submarine springs are usually located on the borders of the areas with acoustic penetration or even at some distance away from them it is possible that the activity of the hot and salty submarine springs controls the acoustic penetration however determination of the exact mechanism for the existence of the zones of acoustic penetration must await further studies of the sediments especially for measurements of various parameters that control the seismic response of the rock another discovery made with the shallow seismic profiles is the existence of some bathymetric irregularities on the floor of the sea of galilee in view of the high sedimentation rate in the lake which tends to smooth the floor a bathymetric irregularity such as a linear bathymetric step could be a surface expression of an active fault

unraveling the mosaic of paleozoic crustal blocks in southeast asia parts of southeast asia show evidence of having paleozoic or older continental crust these include small fragments in the philippine and indonesian archipelagoes new guinea and adjoining shelves and the main area a large mass consisting of nearly all of mainland southeast asia most of sumatra southwestern borneo and parts of the bordering and intervening seas ophiolite belts probable sutures and contrasting geology across them indicate that this main mass is a mosaic of different fragments or blocks

paleomagnetism of peninsular malaysia abstract paleomagnetic results from upper jurassic to paleocene rocks in peninsular malaysia show counter clockwise ccw rotations while clockwise rotations cw are predominantly found in older rocks continental redbeds of the upper jurassic to lower cretaceous tembeling group have a post folding remagnetization giving a vgp at n54 e29 corresponding to approximately 40 of ccw rotation relative to eurasia and 60 ccw relative to the indochina block khorat plateau samples from cretaceous to paleocene mafic volcanics of the kuantan dike swarm and the segamat basalts give vgps at n59 e47 and n34 e36 respectively these malayasian data are indistinguishable from the late eocene and oligocene vgps reported for borneo and the celebes sea and are similar to the eocene vgps reported for southwest sulawesi and southwest palawan the occurrence of ccw deflected data over this large region suggests that much of malaysia borneo sulawesi and the celebes sea rotated approximately 30 to 40 ccw relative to the geocentric axial dipole gad between the late eocene and the late miocene although not necessarily synchronously nor as a single rigid plate these regional ccw rotations are not consistent with simple extrusion based tectonic models cw declinations have been measured in late triassic granites permian to triassic volcanics and remagnetized paleozoic carbonates the age of this magnetization is poorly understood and may be as old as late triassic or as young as middle or late cretaceous the plate or block rotations giving rise to these directions are correspondingly weakly constrained

major shifts in nutrient and phytoplankton dynamics in the north pacific subtropical gyre over the last 5000 years revealed by high resolution proteinaceous deep sea coral δ15n and δ13c records abstract the north pacific subtropical gyre npsg is the largest continuous ecosystem on earth and is a critical component of global oceanic biogeochemical cycling and carbon sequestration we report here multi millennial scale sub decadal resolution records of bulk stable nitrogen 15 n and carbon 13 c isotope records from proteinaceous deep sea corals data from three kulamanamana haumeaae specimens from the main hawaiian islands extend the coral based time series back 5000 yrs for the npsg and bypass constraints of low resolution sediment cores in this oligotrophic ocean region we interpret these records in terms of shifting biogeochemical cycles and plankton community structure with a main goal of placing the extraordinarily rapid ecosystem biogeochemical changes documented by recent coral records during the anthropocene in a context of broader late holocene variability during intervals where new data overlaps with previous records there is strong correspondence in isotope values indicating that this older data represents a direct extension of anthropocene records these results reveal multiple large isotopic shifts in both 15 n and 13 c values similar to or larger in magnitude to those reported in the last 150 yrs this shows that large fluctuations in the isotopic composition of export production in this region are not unique to the recent past but have occurred multiple times through the mid to late holocene however these earlier isotopic shifts occurred over much longer time intervals millennial vs decadal timescales further the 15 n data confirm that the extremely low present day 15 n values recorded by deep sea corals 8 are unprecedented for the npsg at least within the past five millennia together these records reveal centennial to millennial scale oscillations in npsg biogeochemical cycles further these data also suggest a number of independent biogeochemical regimes during which 15 n and 13 c trends were synchronous similar to recent coral records or distinctly decoupled we propose that phytoplankton species composition and nutrient source changes are the dominant mechanisms controlling the coupling and de coupling of 15 n and 13 c values likely primarily influenced by changing oceanographic conditions e g stratification vs entrainment the decoupling observed in the past further suggests that oceanographic forcing and ecosystem responses controlling 15 n and 13 c values of export production have been substantially different earlier in the holocene compared to mechanisms controlling the present day system

the structure of the dead sea basin abstract the dead sea basin is located along the left lateral transform boundary between the arabian and sinai plates its structure and history are known from surface geology drilling seismic reflection and other geophysical data the basin comprises a large pull apart almost 150 km long and mostly 8 10 km wide which is flanked by a few kilometres wide zones of normal faulting the basin formed at about 15 ma or earlier close to the beginning of the transform motion and it reached about half its present length before the end of the miocene a strong negative gravity anomaly records a thick sediment basin fill 5 km under half its length reaching a maximum of 10 km the fill includes a few km of salt ca 6 4 ma which forms several diapirs at any one time large parts of the basin subsided simultaneously but the site of fastest subsidence seems to have shifted northward sedimentation rates reached at least hundreds of metres per million years or more in the miocene and 1 km myr in later periods the basin structure is dominated by longitudinal faults intrabasinal faults which delimit the pull apart and which are the extensions of the major strike slip faults north and south of the basin and normal faults which extend along the basin margins the latter faults express a small component of extension across the basin whereas the pull apart resulted from the much larger lateral motion along the basin in addition transverse faults divide the pull apart into several segments with somewhat different histories the pull apart grew by becoming longer parallel to the transform motion at shallow levels this was probably achieved by normal slip on transverse listric faults while the fill between them was little deformed the crust under the basin was stretched and thinned during basin lengthening which caused its subsidence basin formation was accompanied by uplifting of its flanks by 1 km sparse igneous activity occurred along the basin and its flanks its presence suggests a thermal anomaly in the lower lithosphere beneath the basin and adjacent parts of the transform

book review biogeochemistry of amino acids edited by p e hare t c hoering and k king jr wiley 1980 538 pp 30 50

a review of amino acid racemization studies in quaternary mollusks stratigraphic and chronologic applications in coastal and interglacial sites pacific and atlantic coasts united states united kingdom baffin island and tropical islands abstract amino acid racemization aar studies of quaternary mollusks mostly marine mollusks from coastal deposits are reviewed data obtained in regional studies from the u s atlantic and pacific coasts baffin island the united kingdom and tropical islands are discussed as they relate to method evaluation kinetic model development and aminostratigraphic applications u s pacific coast studies have been employed for estimating tectonic deformation rates study of molluscan zonation patterns in the late pleistocene and in kinetic model evaluation u s atlantic coast studies have identified multiple aminostratigraphic zones in areas with complex morphostratigraphic relationships and have also revealed some important conflicts between aminostratigraphic temperature concepts and radiometric data studies in the united kingdom involving coastal sites and non marine interglacial sites identify some stratigraphic and kinetic conflicts but provide a preliminary chronostratigraphic model for the classical interglacial terminology of the u k middle to late pleistocene baffin island studies involving aar data and u th dating of shells have resulted in some significant revisions of previous chronologic models the arctic environment has also stimulated some novel approaches in the collection and interpretation of aar results tropical island studies though few in number aid in calibration of observed racemization and also aid in correlation of coastal deposits with late pleistocene isotopic ice volume records

internal structure of the dead sea leaky transform rift in relation to plate kinematics abstract the structures along the dead sea transform rift are related to the motions of the sinai and arabia plates which border it and to the irregularities of their boundaries the total slip was 105 km left lateral but the present structures were formed mainly during the last 40 km of slip which probably occurred in the plio pleistocene along the southern half of the transform the strike slip motion takes place on en echelon faults this produces rhomb shaped grabens or pull aparts which are sometimes composite and in which there is local crustal separation thus much of the transform is leaky these structures occur in a morpho tectonic rift valley delimited by normal faults which express a small component of transverse extension along a few segments the shape of the transform is such that lateral motion produces local transverse compression the geometric relations of the structures along the transform define an eulerian pole of relative plate motions at 32 8 n 22 6 e 0 5 the older motion was somewhat different and is described by a pole located about 5 west of the above then the component of transverse extension and crustal separation was much smaller than now while local transverse compression was more important the northern half of the dead sea transform has an irregular shape and the bordering plates did not remain rigid as lateral motion continued here transverse compression is often important

a precis on pre alpine tectonic history of tethyan paleooceans abstract the history of the mediterranean belt saw the emergence evolution and disappearance of several successively existing oceans these were fairly large oceanic crust basins homologues of the present oceans throughout the phanerozoic they separated the northern eurasian from the southern gondwanan continents with geologically established paleomargins that resemble the present continental margins phanerozoic time was marked by the destruction of the southern gondwanan margin of the tethys and accretion of the northern eurasian continental margin the history of the present day eurasia was greatly influenced by the indosinian orogeny which is considered to be on a level with the caledonian hercynian and alpine orogenies

dating deep lake sediments by using amino acid racemization in fossil ostracodes the long term rate of racemization for amino acids preserved in fossil ostracode shells was determined by using independently dated sediment cores from five deep lakes the racemization rates for aspartic and glutamic acids in the common ostracode genus candona were calibrated for the past 100 k y providing the basis for an age equation with a realistic age uncertainty of 20 the new age equation can be applied to other hypolimnic settings because the temperature below the thermocline of deep lakes from middle and high latitude regions can reasonably be assumed to remain close to 4 c the sample size required for analysis is an order of magnitude less than for 14c dating and presents new opportunities to date deposits that are organic matter poor or those with large 14c reservoir effects

the anatomy of a pull apart basin seismic reflection observations of the dead sea basin the dead sea basin dsb located along the african arabian plate boundary constitutes a good example of a pull apart basin because of its large dimensions its structural simplicity and its active subsidence a coherent three dimensional picture of the dsb has been constructed on the basis of analysis of seismic stratigraphy together with the interpretation of previously published geological and geophysical data despite the large known vertical offsets across the basin deformation takes place mainly along the transverse and longitudinal faults and the intervening sediments are relatively undeformed and are hardly tilted comparison between e w seismic lines indicate that the basin has widened by the collapse and tilting of arcuate blocks from the western margin but that its original shape is a full graben the southern and central parts of the basin are divided into equidistant segments 20 30 km long by transverse faults activity along these faults commenced only during the pleistocene long after the dead sea strike slip fault system was formed and migrated northward with time a likely scenario for the development of the dsb is one in which the basin grows northward with time by a simultaneous propagation of the southern strand of the dead sea fault and a retardation of the northern strand

palaeocene early eocene inversion of the phuquoc kampot som basin se asian deformation associated with the suturing of luconia abstract the little explored cambodian and vietnamese phuquoc kampot som basin is a late jurassic to early cretaceous foreland basin developed in response to the build up of a palaeo pacific magmatic arc a combination of seismic data well data and outcrop geology complemented by fission track and u pb analysis is used to unravel the basin history this reveals a hitherto unknown earliest palaeogene basin inversion associated with the luconian suturing to se asia and the shutdown of palaeo pacific subduction underneath se asia the phuquoc kampot som basin and the khorat basin in thailand constitute the erosional remnants of a larger basin that covered large parts of se asia in late mesozoic time and subsequently became segregated during earliest palaeogene inversion and erosion inversion was focused along the several hundred kilometres long kampot and khmer chanthaburi fold belts that confine the phuquoc kampot som basin and merge with the mae ping and the three pagodas fault zones these connections together with local nw se trending sinistral transpressional faults offshore indicate a link between initial se asian left lateral strike slip faulting and the luconian suturing the separation between the once unbroken khmer chanthaburi fold belt and the phetchabun fold belt in thailand suggests a 50 100 km cenozoic left lateral offset across the mae ping fault zone

stratigraphy of late quaternary estuarine deposits and amino acid stereochemistry of oyster shells beneath san francisco bay california abstract the sequence of quaternary deposits beneath the floor of san francisco bay includes four to seven noncontemporaneous estuarine units intercalated with alluvium and dune sand units l 0 10 000 b p m 40 000 b p probably ca 80 000 140 000 b p and n older than unit m are distinctly superposed the dominant molluscan fossil in each of these three units is ostrea lurida carpenter the native oyster along much of the pacific coast of north america despite a lamellar structure that suggests vulnerability to contamination o lurida shells generally yield amino acid enantiomeric ratios that are analytically reproducible and stratigraphically consistent the kinetics of racemization in o lurida conceivably resembles that of protothaca and saxidomus other bivalves whose kinetics of racemization are relatively well understood assuming such a resemblance enantiomeric ratios in o lurida imply that 1 unit m is the same approximate age as estuarine terrace deposits bordering san pablo bay and carquinez strait providing that the terrace deposits have been at diagenetic temperatures 1 2 c warmer than unit m and 2 the age of unit n is about four times greater than that of unit m providing that both units have been at the same approximate diagenetic temperature

reconstructing estuarine conditions oyster shells as recorders of environmental change southwest florida abstract live collected shells of the oyster crassostrea virginica contain geochemical records of modern temperature and salinity so records of prehistoric conditions may be obtained from subfossil shells restoration of channelized watersheds in florida is receiving much attention and plans for targeted watersheds require information about estuarine conditions before channelization lack of historical records necessitates alternative methods to understand pre disturbance conditions a 14c calibrated amino acid geochronology based on racemization of glutamic acid yielded ages ranging from 190 1220 ad and from 1270 1860 ad for subfossil oysters from blackwater river near natural watershed and for faka union bay channelized watershed respectively 18o and 13c values of subfossil shells from blackwater river indicate salinity and summer temperatures similar to present winter temperatures recorded in shells from 190 590 720 and 1050 ad appear 1 5 c colder than present winter temperatures whereas the shell from 1220 ad records winter temperatures similar to modern winter temperatures these temperature shifts may indicate change in climate or natural seasonal variation of winter temperature from year to year subfossils from faka union bay may reflect a complicated hydrology which cannot be evaluated by isotopic compositions alone and demonstrates the need for development of independent elemental proxies for temperature and salinity decreases in 13c from subfossil to modern shells may in part result from co2 added to the atmosphere from fossil fuel burning the suess effect subfossil 13c that is 1 more positive than modern shells suggest a change in the dominant carbon sources from terrestrial c4 or aquatic plants to c3 plants mangroves

the origin of the bir zreir rhomb shaped graben eastern sinai the bir zreir graben a rhomb shaped depression located in eastern sinai is well exposed in three dimensions a nearly horizontal nonconformity between precambrian crystalline basement and overlying phanerozoic sediments contacts of basement plutons and a system of early miocene basaltic dikes permit very precise mapping of the local structures and the determination of vertical and horizontal displacements along faults applying the standard pull apart model to the bir zreir rhomb shaped graben predicts greater vertical separations 3 to 6 times larger than those observed an alternative model based on a rotational movement of the bir zreir block agrees more closely with field evidence it is concluded that the shape and size of the graben was determined by the original fault pattern and that its final shape was changed relatively little by later movements the rotation of the bir zreir block resulted from a combination of sinistral displacement along n s faults a change of their trend to nne and a regional e w extension the model proposed here does not require the presence of large deep gaps along the diagonal faults as in pull aparts

shell sclerochronology and stable isotopes of the bivalve anomalocardia flexuosa linnaeus 1767 from southern brazil implications for environmental and archaeological studies abstract this study presents the first stable isotopic and sclerochronological calibration of the bivalve anomalocardia flexuosa linnaeus 1767 in relation to environmental variables in a subtropical coastal area of southern brazil we investigate incremental shell growth patterns and 18o and 13c values of modern specimens collected alive from the laguna lagoonal system lls shells of anomalocardia flexuosa are also one of the main biological components of pre columbian archaeological shell mounds and middens distributed along the brazilian coastline we therefore selected archaeological specimens from a local late holocene shell mound cabecuda to compare their stable carbon and oxygen isotope values with those of modern specimens shell growth increments 18o and 13c values respond to a complex of environmental conditions involving for example the effects of temperature and salinity the isotopic information extracted from archaeological specimens from cabecuda shell midden in the lls indirectly indicates that environmental conditions during the late holocene were different from present day in particular intra shell 18o and 13c values of archaeological shells reveal a stronger marine influence at 3 ka cal bp which is in contrast to the seasonal freshwater seawater balance that currently prevails at the lls

gerardia bristlecone pine of the deep sea we measured carbon isotope abundances in the layered proteinaceous skeleton of a zoanthid gerardia collected from 620 m depth off the little bahama bank 27 n 79 w the 14c values decreased from 76 in the outer growth edge to an average of 267 in the center of three portions of the skeleton these 14c data suggest an age for this living organism of 1800 300 years the possibility that the large decrease in 14c reflects the gradual input of bomb 14c over the entire growth of the organism is inconsistent with the post bomb 14c values obtained for the most recent growth tips if the age estimate of two millennia is correct it may be the longest lived animal yet observed in the ocean gerardia may serve as a long lived recorder of ocean chemistry similar to the bristlecone pine tree that has served as a millennial timescale recorder for atmospheric 14co2 suess 1980 and climate in particular there is potential for gerardia to serve as a millennial scale integrator of upper ocean particle flux and possibly reveal past changes in the productivity of the surface ocean

late holocene radiocarbon and aspartic acid racemization dating of deep sea octocorals abstract primnoa resedaeformis is a deep sea gorgonian coral with a two part skeleton of calcite and gorgonin a fibrillar protein potentially containing long term records of valuable paleo environmental information for various reasons both radiocarbon and u th dating of these corals is problematic over the last few centuries this paper explores aspartic acid racemization dating of the gorgonin fraction in modern and fossil specimens collected from the nw atlantic ocean radiocarbon dating of the fossil specimen indicates a lifespan of 700 100 years the longest yet documented for any octocoral gorgonin amino acid compositions were identical in the fossil and modern specimens indicating resistance to organic diagenesis similar to bone collagen the fibrillar protein of gorgonin may impose conformational constraints on the racemization of asp at low temperatures the rate of racemization of aspartic acid d l asp was similar to previously published results from an 1800 year old anemone gerardia the age equation was age years bp 2000 ad d l 0 020 002 0011 0001 2 r2 0 97 p d l asp was marginally better than that for 14c dating over the most recent 50 200 years although the dating error may be improved by inclusion of more samples over a broader time range these results suggest that d l asp dating may be useful in augmenting 14c dating in cases where 14c calibrations yield two or more intercept ages or in screening samples for further 14c or u th dating

rapid racemization of aspartic acid in mollusc shells and potential for dating over recent centuries dating of deposits and materials less than 350 years old is hindered by the very poor time resolution of the radiocarbon method over this period1 2 fluctuations in atmospheric 14c levels result in the existence of several possible calendric ages for any given radiocarbon age for terrestrial samples in the marine record these fluctuations are dampened however only a small change in marine radiocarbon ages occurs over this period from ad 1700 to 1950 radiocarbon ages become only 100 yr younger2 consequently age resolution is poor furthermore there is an uncertainty in the amount of the correction for the reservoir effect the apparent radiocarbon age of modern marine carbon typically 400yr which reflects the average residence time of carbon in the oceans amino acid racemization epimerization analysis has been used primarily for dating samples older than the limit of radiocarbon dating 40 000 50 000 yr bp 3 4 here i show that aspartic acid asp in mollusc shells has racemized particularly rapidly over the past few centuries analyses done on land snails from deposits in the negev desert eolianites in madeira cave deposits in jamaica and from museum collections indicate racemization rates of 2 5 per century asp racemization thus provides a means of dating recent faunal assemblages of molluscs and other biogenic carbonates as well as recent terrestrial fluvial and marine sedimentary sequences that contain molluscs

new data on the indosinian orogeny from central thailand the main aspects of the geosynclinal and orogenic evolution of the petchabun foldbelt in central thailand are described this area was previously thought to be deformed by the indosinian triassic orogeny the new data show that the main orogenic event in thailand can be dated post lower permian pre uppermost permian evidence is given that paleotethys closed on thai territory during this orogenic event the known upper triassic deformations in northern thailand are supposed to be strictly intracontinental and therefore of minor importance

isotopic evidence for climate change during the vandal minimum from ariopsis felis otoliths and mercenaria campechiensis shells southwest florida usa archaeological evidence from coastal southwest florida suggests this region and its local inhabitants the calusa were affected by drought and cooling during the vandal minimum climate episode ad 500 800 to test this hypothesis we reconstructed seasonal scale climate conditions using stable oxygen and carbon isotope ratios 18o and 13c preserved in ariopsis felis otoliths and mercenaria campechiensis shells comparing 18o records from both species distinguishes between cool versus warm and wet versus dry conditions 18o values from four otoliths indicate cooling of winter temperatures occurred in the early vandal minimum ad 500 600 and late half of the middle vandal minimum ad 650 700 persistent dry summers punctuated by occasional years with wet summers throughout the vandal minimum were detected from 18o values of eight archaeological shells our climate reconstructions are in good agreement with archaeological observations and with the cool and dry conditions documented in europe

salt diapirs in the dead sea basin and their relationship to quaternary extensional tectonics abstract regional extension of a brittle overburden and underlying salt causes differential loading that is thought to initiate the rise of reactive diapirs below and through regions of thin overburden we present a modern example of a large salt diapir in the dead sea pull apart basin the lisan diapir which we believe was formed during the quaternary due to basin transtension and subsidence using newly released seismic data that are correlated to several deep wells we determine the size of the diapir to be 13 10 km its maximum depth 7 2 km and its roof 125 m below the surface from seismic stratigraphy we infer that the diapir started rising during the early to middle pleistocene as this section of the basin underwent rapid subsidence and significant extension of the overburden during the middle to late pleistocene the diapir pierced through the extensionally thinned overburden as indicated by rim synclines which attest to rapid salt withdrawal from the surrounding regions slight positive topography above the diapir and shallow folded horizons indicate that it is still rising intermittently the smaller sedom diapir exposed along the western bounding fault of the basin is presently rising and forms a 200 m high ridge its initiation is explained by localized e w extension due monoclinal draping over the edge of a rapidly subsiding basin during the early to middle pleistocene and its continued rise by lateral squeezing due to continued rotation of the amazyahu diagonal fault

the stable oxygen and carbon isotopic record from a coral growing in florida bay a 160 year record of climatic and anthropogenic influence abstract a 160 year record of skeletal 13 c and 18 o was examined in a specimen of the coral solenastrea bournoni growing in florida bay variations in the 18 o of the skeleton can be correlated to changes in salinity while changes in the 13 c reflect cycling of organic material within the bay based on the correlation between salinity and skeletal 18 o we have concluded that there has been no long term increase in salinity in this area of florida bay over the past 160 years using salinity correlations between the various basins obtained from instrumental data we have been able to extend our interpretations to other parts of florida bay reaching similar conclusions in contrast to current ideas which have focused on changes in florida bay water quality over the past 20 yr history of the bay as causative in its decline we have determined that changes in water quality in this basin were already set in motion between 1905 and 1912 by the construction of the florida east coast railway from miami to key west the construction of the railway resulted in the restriction of the exchange of water between the florida reef tract and the gulf of mexico causing florida bay to become more eutrophic evidence of this process is observed in the sudden shift to relatively lower 13 c values coincident with railway construction natural events also appear to have influenced the water in the bay between 1912 and 1948 frequent hurricanes had the effect of increasing exchange of water between the bay and reef tract and removing large quantities of organic rich sediments however since 1948 the number of hurricanes affecting the area has decreased and the products of the oxidation of organic material have been increasingly retained within the basin promoting the initiation of eutrophic conditions

the bentong raub suture zone abstract it is proposed that the bentong raub suture zone represents a segment of the main devonian to middle triassic palaeo tethys ocean and forms the boundary between the gondwana derived sibumasu and indochina terranes palaeo tethyan oceanic ribbon bedded cherts preserved in the suture zone range in age from middle devonian to middle permian and melange includes chert and limestone clasts that range in age from lower carboniferous to lower permian this indicates that the palaeo tethys opened in the devonian when indochina and other chinese blocks separated from gondwana and closed in the late triassic peninsular malaysia segment the suture zone is the result of northwards subduction of the palaeo tethys ocean beneath indochina in the late palaeozoic and the triassic collision of the sibumasu terrane with and the underthrusting of indochina tectonostratigraphic palaeobiogeographic and palaeomagnetic data indicate that the sibumasu terrane separated from gondwana in the late sakmarian and then drifted rapidly northwards during the permian triassic during the permian subduction phase the east malaya volcano plutonic arc with i type granitoids and intermediate to acidic volcanism was developed on the margin of indochina the main structural discontinuity in peninsular malaysia occurs between palaeozoic and triassic rocks and orogenic deformation appears to have been initiated in the upper permian to lower triassic when sibumasu began to collide with indochina during the early to middle triassic a type subduction and crustal thickening generated the main range syn to post orogenic granites which were emplaced in the late triassic early jurassic a foredeep basin developed on the depressed margin of sibumasu in front of the uplifted accretionary complex in which the semanggol formation rocks accumulated the suture zone is covered by a latest triassic jurassic and cretaceous mainly continental red bed overlap sequence

structural evolution of mesozoic peninsular malaysia field evidence from upper palaeozoic and mesozoic strata exposed in peninsular malaysia demonstrates that the structural style degree and orientation of folding axial plane cleavage and faulting in the triassic jurassic and cretaceous rocks of the central basin are remarkably similar in contrast the upper palaeozoic strata especially the carboniferous rocks exposed in the eastern part of the peninsula show multiple phase folding and regional metamorphism unlike anything seen in the mesozoic rocks these observations demonstrate that two important compressional events affected peninsular malaysia one in late permian times and the other in the mid to late cretaceous the late palaeozoic compressional event was a major orogenic mountain building phase with associated emplacement of major permo triassic granite plutons that form the eastern and main ranges no indications were found of the widely reported triassic orogenic compression the palaeotectonic and palaeogeographical implications of these discoveries are important for interpreting the evolution of eastern gondwana and tethys the raub bentong line was an important fault zone active during the mesozoic but does not appear to have been a major tectonic suture since the late palaeozoic we postulate that the permo triassic granites of the eastern belt and those presently exposed in the main range were originally about 30 50 km apart and that triassic and jurassic crustal attenuation and subsidence led to the separation of these two granitic belts by more than 100 km

epitaxial salt reefs and mushrooms in the southern dead sea salt usually accumulates in shallow ephemeral brines as simple flat beds however in permanent brines deepening in solar evaporation ponds in the southern dead sea salt accumulation is complicated by the growth of isolated vegetable like salt structures

magnetic field over the dead sea and vicinity abstract a detailed magnetic survey was conducted in the dead sea a large sedimentary basin within the dead sea rift the magnetic anomaly map shows two distinct provinces in the north the anomaly field trends north south and decreases towards the east with a gradient of 10 to 20 nt km in the south the field trends east west the magnetic field is generally smooth and most of the magnetic anomalies have long wavelengths and low amplitudes however a few short wavelength anomalies exist some of which have high amplitudes they may indicate the presence of small basaltic bodies buried at shallow depths a comparison between the magnetic anomaly map of the dead sea and aeromagnetic maps over the land areas to the west and east show that the magnetic anomalies extend uninterrupted from the land area to the west into the basin this configuration suggests that faulting on the western margin of the basin is basically normal in the east the magnetic contours are discontinous across the eastern margin of the basin which suggests that the eastern fault is a strike slip fault a very active fault of unknown nature borders the basin in the south this is associated with magnetic anomalies seismic activity and possibly hydrothermal activity there is no indication of faulting on the northern margin of the lake

active transform fault zone at the fringe of the dead sea basin the evolution of an asymmetric basin at the edge of a pull apart structure is studied using geophysical observations and mechanical modeling a new seismic analysis of the northern edge of the dead sea basin indicates recent subsidence folding and oblique faulting along the jericho strike slip fault a main segment of the dead sea transform fault the subvertical fault trace crosses the entire sedimentary sequence typically branching in the shallow subsurface the seismic analysis reveals the three dimensional structure of the area as an asymmetrical basin bordered on the east and on the west by long monoclinic folds the thickness of the sedimentary fill varies from 1 4 km near the present lake shores to a few hundreds of meters about 10 km northward the subsidence is partitioned between a vertical component of slip along the jericho fault and the simultaneously active monoclines bordering the basin we present a model and simulations that reconstruct the present basin structure in the uppermost part of the crust and demonstrates the generation of flexures along the basin margins without horizontal shortening we show that the basin asymmetry and the association of folds and fault can be explained as a long term ductile response of the sediments to local subsidence the asymmetry along the basin is a consequence of a later vertical displacement component on a pre existing strike slip fault our analysis points to ongoing northward propagation of the dead sea basin and provides an explanation for the structural asymmetry of the basin margins

carbon isotopes in recent planktonic foraminifera a record of anthropogenic co2 invasion of the surface ocean abstract the release of isotopically light anthropogenic co 2 into the ocean atmosphere carbon reservoir has resulted in a decrease in the carbon isotopic composition of the surface ocean in this paper we examine differences between the carbon isotope composition of planktonic foraminifera from sediment traps with older late holocene material to estimate the change in 13 c 13 c in eastern atlantic surface waters as a result of the invasion of anthropogenic co 2 using stable oxygen isotopes we demonstrate that average trap values for a variety of species are more or less identical to core top values suggesting that foraminifera recovered in sediment traps are representitive of foraminifera deposited in the sediments however carbon isotopes recorded in planktonic foraminifera from recent trap material reveal a decrease in the 13 c composition of all species relative to the core top samples although the magnitude of the decrease varies significantly between species surface dwelling foraminifera g ruber g bulloides show 13 c values of 0 53 to 0 62 which is similar to other estimates from shallow water coral and sponge records for the decrease in the 13 c composition of dissolved organic carbon in surface waters which has taken place since the start of the anthropogenic emissions the magnitude of decrease in the 13 c of surface waters suggested by these records is also close to that predicted by global carbon cycle models deeper thermocline dwelling foraminifera such as g inflata however show 13 c values 0 2 which are substantially lower than their surface dwelling counterparts this reduction in 13 c with increasing depth habitat within the mixed layer may be related to limited vertical penetration of anthropogenic co 2 as a result of the strong upwelling which is observed in the eastern atlantic along the northwest african margin

oxygen isotopic evidence for greater seasonality in holocene shells of donax variabilis from florida abstract donax variabilis the variable coquina clam has been a common inhabitant of exposed sandy beach intertidal and shallow subtidal zones in the southeastern united states throughout the pleistocene and holocene it is ideally suited for paleotemperature studies because it is restricted to environments of well mixed normal marine seawater with a fairly uniform isotopic composition as a result oxygen isotopic variability in d variabilis shells is largely explained by temperature variation although d variabilis is small and short lived its shell represents an important paleoclimate archive because of its unique habitat preference high resolution sampling of individual d variabilis shells and comparison of oxygen isotopic temperature profiles with historical seawater temperatures from the northeastern florida coast indicate rapid shell growth over a brief life span of three to five or six months analysis of two modern shells reveals a close correspondence between isotopically determined water temperatures and historical water temperatures during the spring summer growing season paleotemperature profiles from four archaeological shells however suggest a longer growth interval spanning summer autumn two preceramic archaic period shells ca 4240 and 5570 14c yr bp and two orange period archaic shells ca 3600 and 3760 14c yr bp from four different archaeological sites yield paleotemperatures that average 3 5 c higher than present summer autumn water temperatures these warm paleotemperatures highlight seasonality differences associated with the mid holocene hypsithermal climatic interval in this region

stable nitrogen and carbon isotope δ15n and δ13c variability in shallow tropical pacific soft coral and black coral taxa and implications for paleoceanographic reconstructions abstract soft corals and black corals are useful proxy tools for paleoceanographic reconstructions however most work has focused on deep water taxa and few studies have used these corals as proxy organisms in shallow water

distribution of holocene sediments and neotectonics in the deep north basin of the dead sea abstract the distribution of holocene sediments and active faults in the central portion of the northern dead sea basin was analyzed from high resolution seismic reflection data the seismic reflection profiles reveal that sediments buried at a shallow depth are flat lying continuous and unfaulted within the central basin floor four prominent subsurface seismic reflectors were identified that based on limited core data represent the contact between rock salt and marl layers isopach and structural maps of recent sediments indicate an asymmetry of active subsidence with thick accumulations located closer to the east margin of the basin sediment thickness increases within a rhomb shaped depression whose long axis is oriented approximately 20 30 counterclockwise to the regional basin bounding faults the morphology and trend of the locus of maximum subsidence suggests tectonic control of the depression however the proximity of the depocenter of recent sediments to the ein gedi diapir and rim depression suggests that local sub basinal subsidence may also be related to movement of rock salt at depth the basinal strata are deformed along the faults that form a bathymetric escarpment along the west east and south margins of the north basin of the dead sea thinning of recent sediments toward the faults indicates syntectonic deposition

phanerozoic plate boundaries in mainland se asia the himalayas and tibet recently available geological data on tibet yunnan and burma facilitate recognition of phanerozoic subduction systems and two continental fragments of gondwanaland which extend through mainland se asia a cambrian subduction system and 5 mesozoic early caenozoic collision belts are identified in the region indochina eastern thailand and central tibet accreted to china in the early triassic western se asia and s tibet separated from gondwanaland in the permian or early triassic and collided with asia in the late triassic and the western burma island arc system collided with asia in the jurassic upper triassic flysch and schist in the eastern indoburman ranges were accreted to western burma in the jurassic early cretaceous during eastward subduction and formation of a back arc thrust belt following collision of greater india with arc complexes to the n in the cretaceous and with tibet in the early eocene western burma moved northwards about 450 km along the sagaing namyin ridge thrust transform fault formation of the 3 major belts of tin granites and the porphyry copper deposits in the region took place in specific tectonic settings within the subduction systems and collision belts

sclerochronology and geochemical variation in limpet shells patella vulgata a new archive to reconstruct coastal sea surface temperature 1 climate archives contained in shells of the european limpet patella vulgata accumulated in archaeological deposits can potentially provide much needed information about holocene environmental change in midlatitude coastal areas before reconstructing climate information preserved in these zooarchaeological records we studied the controls on oxygen and carbon isotope ratios 18o and 13c respectively in modern specimens we tested the hypothesis that p vulgata precipitates its shell in isotopic equilibrium with the ambient water by comparing 18oshell with predicted values predicted 18oshell was constructed using observed sea surface temperature sst records and the equilibrium fractionation equation for calcite and water we assumed a constant 18owater value of 0 10 vsmow based on published regional measurements comparison of 18oshell with predicted values revealed that 18oshell values were higher than expected by 1 01 0 21 consequently estimated sst calculated from 18oshell was 4 2 2 3 c lower than observed sst however because of the relatively uniform offset between observed and expected 18o an adjustment can be made to account for this predictable vital effect thus past climate can be reliably reconstructed using this temperature proxy once the offset is taken into account 13c values have a similar cyclicity to the 18o variation and therefore vary seasonally however 13c is slightly out of phase relative to 18o an overall negative shift in 13cshell over the lifetime of the individual indicates a vital effect associated with ontogeny further study of environmental and ecological factors that influence shell 13c is required to evaluate fully the potential of carbon isotope ratios as a useful environmental proxy

nan river suture zone northern thailand the nan river suture zone consists of a belt of ophiolitic mafic and ultramafic rocks formed in a back arc or inter arc setting and metasedimentary rocks including epidote crossite blueschists that may represent an inner trench sequence these rocks are probably pre permian in age the nan river belt forms part of the suture between the indosinian and shan thai cratonic blocks and is inferred to correlate with the changning shuangjiang suture zone in southern china

carbon isotope records from extant caribbean and south pacific sponges evolution of δ13c in surface water dic stable isotope records of demosponges from the caribbean and coral sea are described for the purpose of studying the influence of fossil fuel co2 on the carbon isotopic composition of dissolved inorganic carbon dic in surface water the slow growing sponges precipitate calcium carbonate in isotopic equilibrium with ambient sea water and are used to detect changes in 13cdic from pre industrial times early 19th century to the present we observed similar shapes and ranges in 13c curves measured on caribbean specimens collected from water depths of 25 84 and 91 m as well as a specimen collected in shallow waters off new caledonia the records reveal a highly significant correlation with atmospheric 13cco2 13cdic values for caribbean and coral sea surface waters were calculated using the 13c sponge records while 13c of atmospheric co2 decreased by about 1 4 from the early 19th century to 1990 13cdic of caribbean and coral sea surface waters decreased by 0 9 0 2 and 0 7 0 3 respectively no isotopic equilibrium between surface water dic and atmospheric co2 was observed either during the pre industrial steady state or during the last 100 years the lower amount of depletion in the surface water 13cdic with respect to the atmospheric anthropogenic signal is explained by the dilution of the surface waters by biologically altered subsurface water dic the lower 13c decrease in the coral sea points to a stronger influence of the subsurface water source compared to the caribbean

the permo triassic paleotethys in mainland southeast asia and adjacent parts of china aspects of the geodynamic evolution of mainland southeast asia and china are discussed in consideration of the permo triassic paleotethys problem it is shown that all sutures in thailand vietnam and yunnan already closed during the paleozoic era and that the entire region must be regarded as part of the northern continents the permo triassic paleotethys must be expected south of tibet and in burma

late holocene radiocarbon variability in northwest atlantic slope waters abstract deep sea gorgonian corals secrete a 2 part skeleton of calcite derived from dissolved inorganic carbon at depth and gorgonin derived from recently fixed and exported particulate organic matter radiocarbon contents of the calcite and gorgonin provide direct measures of seawater radiocarbon at depth and in the overlying surface waters respectively using specimens collected from northwest atlantic slope waters we generated radiocarbon records for surface and upper intermediate water layers spanning the pre and post bomb 14 c eras in labrador slope water lsw convective mixing homogenizes the pre bomb 14 c signature 67 4 to at least 1000 m depth surface water bomb 14 c signals were lagged and damped peaking at 45 in the early 1980s relative to other regions of the northwest atlantic and intermediate water signals were damped further off southwest nova scotia the vertical gradient in 14 c is much stronger in surface water pre bomb 14 c averaged 75 5 at 250 475 m depth pre bomb 14 c oscillated quasi decadally between 80 and 100 likely reflecting interannual variability in the presence of labrador slope water vs warm slope water wsw finally subfossil corals reveal no systematic changes in vertical 14 c gradients over the last 1200 yr

oyster shells as recorders of short term oscillations of salinity and temperature during deposition of coral bioherms and reefs in the miocene lorca basin se spain abstract we use 18 o and 13 c of oyster shells inferred seawater 18 o w and temperature tolerance ranges of modern zooxanthellate coral communities to constrain and model paleo salinities of marginal marine waters of the miocene lorca basin spain salinities ranged from 22 to 32 psu during growth of coral bioherms and carpets of the soriana and parrilla formations and from 35 to 39 psu during deposition of the hondo formation reef complex the periods with lower modeled salinities correspond with deltaic and alluvial fan sedimentation in the area the modeling is supported by 87 sr 86 sr data and provides new insights into the evolution of the local depositional settings departures of sr isotope values from the global oceanic curve occur within the intervals with the lowest modeled salinities and the non oceanic 87 sr 86 sr preserved in individual oyster shells was probably sourced from uplifted aquitanian burdigalian limestones 87 sr 86 sr values that plot along the global ocean sr isotope curve for the late miocene indicate a tortonian age for the upper part of the soriana formation and the parrilla formation and a messinian age for the hondo formation more generally we demonstrate how the chemical analyses of oyster shells provide additional information regarding short term oscillations of salinity and temperature of seawater beyond what can be obtained by traditional paleoecological methods

reconstruction of eastern gondwanaland substantial additions of large continental blocks to the smith et al 1 model of eastern gondwanaland are proposed here largely on the basis of the distribution of key land floras tropical and subtropical marine faunas lithofacies patterns and the identification of a triassic magmatic arc that characterized all the eastern margin of gondwanaland the continental fragments that must have been rifted from northern australia new guinea in the jurassic are identified as south tibet burma thailand malaya and sumatra the original site of deposition of the subtropical permian limestones and tropical late triassic limestones overthrust onto the northern margin of australia by the late cenozoic collision2 is located in this greater gondwanaland palaeomagnetic data except those from malaya3 support this reconstruction

substratum transverse faults in kuqa foreland basin northwest china and their significance in petroleum geology abstract the importance of transverse faults in basin evolution and petroleum geology has been often emphasized however the transverse faults in the kuqa foreland basin the most important gas producing area in china have rarely been studied interpreted seismic sections and earthquake focal mechanism solutions as well as other geological and geophysical data allow us to identify a few widely spaced approximately ns trending transverse strike slip faults separating major structural units and to clarify the geometry and kinematics of these transverse faults hidden below thrust faults in the kuqa foreland basin two major structural domains can be distinguished transverse faults in the northern kuqa foreland basin are mainly nne trending sinistral indicating clockwise rotation of fault bounded blocks in contrast the predominant nw trending dextral faults in the southern kuqa foreland basin imply counterclockwise rotation of fault bounded blocks we propose a tectonic model in which crustal blocks are bounded by strike slip faults in a zone of simple shear rotation about vertical axis the strike slip faulting and thrust faulting in the kuqa foreland basin suggest that some of the convergence between south tianshan and tarim blocks may have been accommodated not only by obvious crustal shortening and thickening along thrust faults but also by rotation and possible lateral movement of the crust along transverse faults controlled by the remote collision of indian block with eurasian block since the miocene these reactivated substratum faults which may inherit from paleozoic deformation control various elements relevant to gas accumulation in the kuqa foreland basin which should expect to be paid more attention in the future these elements include maturity of tertiary and jurassic source rocks a difference in the regional cap of kumugelimu salt beds from east to west reservoir bed properties gas migration channels and traps formation in addition the strike slip faulting of the transverse faults may affect deformation of the sedimentary cover including making the western qiulitag structural belt to form an arcuated structure curved to the ssw

shell midden sclerochronology abstract sclerochronological analysis of shell midden faunal remains offers a unique opportunity to study climate and environmental change in relation to human activity middens exist near most aquatic habitats almost worldwide for much of the late pleistocene and holocene they afford good preservation of accretionary calcium carbonate remains such as mollusk shells and fish otoliths in comparatively well dated contexts as such midden samples are a source of sequential proxy records of past climate and environmental conditions and may provide detailed pictures of human environment interaction however midden samples present several challenges to the development and application of sclerochronological proxies including unique taphonomic concerns here these challenges are outlined within descriptions of the major applications of midden sclerochronology archeological concerns including season of capture reconstructing the history of anthropogenic environmental impacts and paleoclimate environment proxy reconstructions

the indian ocean 13c suess effect the 13c of dissolved inorganic carbon dic decrease the 13c suess effect in the indian ocean was calculated using a multiparameter linear regression comparison of the 1978 geochemical ocean sections study and 1995 world ocean circulation experiment 13c of dic hydrographic and nutrient data the surface ocean 13c decrease rate along 80 and 115 e ranged from approximately 0 1 decade 1 at 55 s to a maximum of approximately 0 18 decade 1 at 35 s and decreased northward to around 0 13 decade 1 at the equator using a global extrapolation based on ocean model results bacastow et al 1996 and previous 13c changes calculated from 1970 to 1993 station reoccupations in the pacific ocean and based on preformed 13c versus chlorofluorocarbon age trends in the indian pacific and atlantic oceans sonnerup et al 1999 an ocean wide average surface ocean 13c rate of change of 0 15 to 0 17 decade 1 was estimated the average depth integrated 13c change rate between 1978 and 1995 along 80 and 115 e was 6 9 0 5 m yr 1 from 58 s to 5 n

structural geometry and evolution of the dead sea jordan rift system as deduced from new subsurface data abstract analysis of deep drilling data and seismic reflection surveys obtained in recent years permit establishment of a tectonic model of the dead sea jordan rift system that is in part conformable with some of the many often controversial theories on this subject but which also introduces new information negating some concepts that are widely accepted in the literature the dead sea jordan rift system is not a tensional graben between two parallel sets of faults but instead can be best defined as a sinistral transform connecting an incipient oceanic ridge the red sea with an upthrusted collision zone the taurus range the shear is caused by the opening of the red sea and the motion of the arabian sub plate away from the african plate the shearing occurs along a largely south north trending slightly arcuate une consisting of a series of en echelon left stepping left lateral strike slip master faults of varying lengths these faults characteristically die out to the north by bending outward northeast and the movement is taken up by the strike slip faults to the left i e to the west where overlap of the two faults occurs very narrow and very deep grabens have evolved in places the width being equal to the depth the narrowness of these grabens is dictated by the closeness of the overlapping segments of the successive strike slip faults this feature points to the probability that the en echelon strike slip faults have a common root zone at great depth these grabens are not typical leaky pull aparts in that they have no gravimetric magnetic or heat flow anomalies nor are they closed on all four sides by large faults their northern ends are characterized by gradually rising graben floors without major diagonal cross faults the dead sea jordan rift system sensu stricto extends over a distance of 420 km from the northern shore of the gulf of elat to the northern margin of the hula valley southward it is connected with the red sea along the gulf of elat transition zone which has elements of strike slip as well as tensional opening a northern transition zone exists between the hula valley and the taurus arc where diminishing strike slip movement is compensated by several underthrust belts the time of the beginning of the movement along the rift can be established as pre middle miocene because mid miocene sediments overlie an upper cretaceous graben floor rifting has continued intermittently to the present volcanism in the northern fifth of the rift is genetically associated with the seismically active tensional golan hauran jebel drouz wadi sirhan tectonic trend which has a north west southeast orientation and not with the north south trending dead sea jordan rift

impact of skeletal heterogeneity and treatment method on interpretation of environmental variability from the proteinaceous skeletons of deep sea gorgonian octocorals abstract the stable isotope geochemistry of gorgonian octocoral skeletons facilitates detailed time series reconstructions of nutrient biogeochemistry however comparisons among reconstructions from different locations require realistic estimates of the uncertainty surrounding each measured geochemical value here we determine quantitative uncertainties related to 1 standard skeletal pretreatment in preparation for stable isotopic analysis and 2 biological variability associated with a heterogeneous isotopic composition of the gorgonin skeleton we found that the 5 hcl pretreatment required for the 13c measurements does not significantly impact the 15n values of the skeleton nor the reproducibility of the 15n measurements in contrast while 5 hcl pretreatment significantly altered bulk 13c values via removal of caco3 it did not change amino acid 13c values in the organic skeleton we found that the variance of repeat measurements of skeleton samples formed contemporaneously and homogenized skeleton for both 13c and 15n exceeded that of instrumental uncertainty of an acetanilide standard this indicates that instrumental uncertainty underestimates the true precision of an isotopic measurement of the organic skeleton furthermore measurements of contemporaneous skeleton around the circumference of an octocoral colony yielded variability exceeding that of homogenized skeleton based on these results we find that 1 both 13c and 15n values can be measured simultaneously in pretreated skeleton 2 growth bands should be homogenized prior to analysis and 3 reported error should include uncertainty due to biological effects determined from repeat analysis of homogenized skeleton and not just instrument error to reduce false significant differences our results present an important protocol for processing proteinaceous octocoral skeletons and propagating uncertainty to more accurately reconstruct nutrient dynamics from proteinaceous deep sea octocoral skeletons

growth rate variation and potential paleoceanographic proxies in primnoa pacifica insights from high resolution trace element microanalysis red tree coral primnoa pacifica is one of the more common habitat forming deep sea gorgonian corals in the northeast pacific ocean growing in colonies up to 2 m high and living for decades to hundreds of years growth characteristics of p pacifica were studied in dixon entrance northern british columbia and the olympic coast national marine sanctuary washington state usa based on samples collected in july 2008 to minimize the impact of scientific sampling on coral populations only dead coral skeletons and dislodged live corals were collected ages and growth rates were measured using band counts and checked against ams 14 c ages of gorgonin rings ba ca mg ca na ca and sr ca ratios in the calcite cortex were measured using radial secondary ion mass spectrometer sims transects with a spot size of 20 m and separation distance of 25 m growth banding was consistent in width between the central mixed zone consisting of calcite and gorgonin and the dominantly calcite cortex average annual radial growth rate of the nine corals analysed ranged from 0 23 to 0 58 mm yr with an average growth rate of 0 32 mm yr in dixon entrance and 0 36 m yr in ocnms these growth rates are slightly higher than p pacifica growth rates from the gulf of alaska and more than four times the growth rates of sister species primnoa resedaeformis in the northwest atlantic primary productivity is likely a more important driver of geographic variation in primnoa growth rates than temperature or current strength both dixon entrance and ocnms are areas with high primary productivity and strong tidal currents lack of post atomic bomb radiocarbon in all but one of the gorgonin samples and long radiocarbon reservoir ages in the northeast pacific made radiocarbon based verification of coral ages and growth rates difficult due to wide errors in calibrated age estimates mg ca and sr ca ratios were inversely correlated in two of the three corals analyzed and showed evidence of interannual variation mg ca ratios ranged from 70 to 136 mmol mol 1 and sr ca ratios from 2 041 to 3 14 mmol mol 1 previously published relationships between gorgonian calcite mg ca and seawater temperature yielded average temperatures matching ambient measurements but the intra and inter annual variation in apparent temperature based on the mg ca ratios was more than double the observed variation in modern seawater temperature ranges in the region annual variation in mg ca and sr ca could be related to seasonal changes in precipitation efficiency which is likely a function of short term fluctuations in coral growth rate in turn related to variation in primary productivity seasonal and interannual variations in food availability driven by primary productivity may affect skeletal growth rate hence mg ca and sr ca ratios primnoid coral skeletal microgeochemistry probably records temporal changes in both temperature and primary productivity

proteinaceous corals as proxy archives of paleo environmental change abstract high resolution marine data are critical to evaluating anthropogenic impacts on our environment considering the spatial and temporal limitations of direct instrumental measurements proxy data extracted from marine environmental archives are necessary to separate anthropogenic changes from those that would occur naturally the majority of late holocene high resolution environmental reconstructions are derived from marine carbonates including tropical scleractinian corals bivalves crustose coralline algae and sclerosponges however these archives are restricted to the top hundreds of meters of the water column and only preserve environmental variability that is captured by calcium carbonate skeletons at a very few select locations marine sediments archive annual environmental variability in organic and inorganic materials recently additional types of corals are proving to yield information complimentary to these traditional marine archives including cold water scleractinian corals and proteinaceous corals a taxonomically diverse group the proteinaceous corals are broadly defined as those having a branching gross morphology with skeleton comprised at least partly of protein rich organic material they encode characteristics of their food and ambient environment into the chemical and physical composition of their skeleton this environmental encoding combined with their banded skeleton and significant longevity means that proteinaceous corals hold information in their skeleton that helps fill the spatial and temporal gaps in our knowledge of past and present ocean conditions here i review the environmental reconstructions derived from geochemical measurements of the proteinaceous coral skeletons this information is grouped into the mesopelagic environmental variability captured in the skeleton of bamboo corals surface processes captured in the organic skeletons of corals across all ocean depths and environmental variability documented by skeletal radiometric isotopes we include animals from two separate subclasses within the class anthozoa including the parasitic zoanthids that secrete a sclero proteic skeleton since the proteinaceous corals are taxonomically diverse we consider the unique features that define this group of corals including their distribution morphology nutrition and longevity we find that uncertainty surrounding biological parameters limits the precision of reconstructions derived from the calcitic skeleton in contrast analytical effort and cost constrain the number of reconstructions from the organic skeleton through this discussion we provide insights into the uses challenges and directions for future research for this important environmental archive

the dual nature of the alpine himalayan system progress problems and prospects abstract two distinct groups of sutures belonging to two different orogenic complexes have been recognized within the alpine himalayan system associated with the development of the tethyan chains they are interpreted as places where two independent tethyan ocean complexes viz palaeo and neo tethys vanished during the permo carboniferous to early cretaceous and the late cretaceous to the present intervals respectively the older orogen is called the cimmerides and the younger the alpides cimmerides and alpides together constitute the super orogenic complex tethysides tethyside orogenic events also generated vast cratonic fields of deformation in eurasia until recently the recognition of these two orogenic complexes hidden within the alpine himalayan system had been hindered because of the artificial tripartite grouping of orogenic events of the phanerozoic into caledonian hercynian and alpine orogenic eras the most important current problems in the study of the tethysides are the relative importance of the various suture strands as sites of consumption of main tethyan oceanic branches the precise timing of ocean opening and closing along these sutures and the original provenance of the continental blocks constituting the tethyside orogenic collage a number of avenues of future research are suggested to tackle these problems

higher than present holocene sea level events recorded in wave cut terraces and scarps old island beaufort county south carolina abstract wave cut terraces and scarps record at least two higher than present holocene sea level events in coastal south carolina the higher event reached 110 cm and the lower 80 cm above local mean spring high water mshw these events occurred subsequent to the formation of the holocene old island barrier island and prior to wilmington aboriginal occupation 1600 years ago shell middens are located on the terrace surfaces these wave cut features were formed in a marsh filled lagoon sheltered from the open ocean by seaward barrier islands these terraces and scarps are evidence supporting the higher than present sea level events predicted for this region by the clark et al 1978 geophysical model of holocene sea level recovery in addition they support a fairbridge 1961 type holocene sea level curve one characterized by oscillations above and below present position holocene sea level fluctuations probably were a prime factor in the episodic progradation of this area given that in this vicinity the nearshore region is the primary sand source

gondwana and cathaysian blocks palaeotethys sutures and cenozoic tectonics in south east asia the triassic indosinian orogeny followed extinction of the palaeotethys ocean resulting in suturing of gondwana affinity and cathaysian blocks

transverse faults at the northern end of the southern basin of the dead sea graben abstract classical models for pull apart basins along strike slip faults predict normal motion along the transverse faults which cross the basin a detailed geophysical investigation was carried out across the northern end of the southern sub basin of the dead sea depression the study included analysis of newly obtained 3 5 khz seismic profiles and reinterpretation of existing single channel sparker seismic profiles and multichannel seismic profiles the unique combination of very shallow and deep seismic profiles reveals the recent activity of a transverse fault in the study area and helps trace its direction the northern end of the southern sub basin was probably characterized by normal movement during the miocene early pleistocene thereafter during the late pleistocene present the mode of its activity changed to strike slip movement