proxy interpretation of coral recorded seawater δ18o using 1 d model forced by isotope incorporated gcm in tropical oceanic regions the oxygen isotopic ratio in the seawater 18osw recorded in 18o of coral skeleton for several centuries in tropical regions is an important variable for reconstructing the past climate however the relationship between 18osw and hydrological balance has not been clearly uncovered yet in this study a one dimensional ocean budget model forced by the global quasi reanalysis isotope data which is the output of an isotope incorporated global spectral model is employed to simulate 18osw the results from the simulations are compared with 31 coral records in tropical oceanic regions the 1 d model successfully reproduces 18osw in 21 coral records indicating these corals have the potential to reconstruct the local hydrological budget the results also confirm that the reproducibility of the 1 d model generally increases with the annual precipitation variability however in the regions where the precipitation variability is less it is more difficult to reconstruct climatic information from the 18osw since the nonlocal physical processes unaccounted for in the 1 d model may affect 18osw the sensitivity analysis of the 1 d model shows that in tropical oceanic regions the large scale precipitation is the dominant factor for 18osw confirming that 18osw recorded in the coral records is a proxy for the precipitation anomaly this study implies that 18osw is more closely associated with precipitation and local water isotope budget in tropical oceanic regions than elsewhere and that the 1 d model is a useful approach for the proxy interpretation in tropical oceanic regions

new insights on 3 d plates interaction near taiwan from tomography and tectonic implications abstract recent tomographic results are used to trace the south china sea and philippine sea subducting slabs south and northeast of taiwan along the manila and ryukyu trenches respectively in particular the 3 d plates interaction beneath taiwan is discussed based on a close up view of the tomographic sections together with earthquake hypocenters distribution our study indicates that 1 the east dipping south china sea slab can be followed to the north up to the latitude of hualien 2 the eurasian plate subducts beneath most part of the taiwan island down to the 670 km depth discontinuity 3 the north dipping philippine sea slab can be followed slightly west of the longitude of hualien both plates thus interact beneath northern taiwan where the arc continent collision is paroxysmal 4 slab detachment is envisaged at the northern edge of the subducted eurasian plate beneath the coastal range of taiwan which may facilitate the northwestward motion of the philippine sea plate with respect to eurasia slabs geometries obtained from tomographic sections allow us to reconstruct the late neogene plate kinematics and dynamics in this region our main conclusions are 1 the size of the original south china sea was about twice its present size 2 the subducted part of the west philippine basin i e the largest oceanic basin of the philippine sea plate extends only 400 km north of the ryukyu trench 3 slab detachment might have occurred 3 5 my ago beneath the central and northern ryukyu arc along a weak zone that is aligned with the gagua ridge an ancient plate boundary 4 the ryukyu trench has propagated westward from 126 e of longitude southeast of miyako island to the locus of the present arc continent collision along a major lithospheric tear that cut through the continent ocean boundary first and then through the continental lithosphere as a consequence the southern ryukyu margin developed progressively from east to west as a subduction zone during the last 8 my it has been elaborated onto a passive margin which corresponded to the edge of the eurasian continental shelf bordering the south china sea prior to pliocene 5 the southern okinawa trough rifted during the last 2 1 ma following the propagation of the subduction zone 6 subduction of the eurasian margin probably stopped recently beneath northern taiwan and a flip of subduction from west to east is being initiated near hualien

active continental subduction and crustal exhumation the taiwan orogeny a tectonic model of active continental subduction followed by crustal exhumation is proposed to explain the orogeny in taiwan the subducted crust is represented by a low velocity zone dipping eastwards beneath the major part of taiwan while the exhumed crust is marked by a high velocity bulge high heat flow and absence of seismicity beneath the eastern central range the boundary between the subducted and exhumed crust has been identified from surface geology and analyses of thermal history across the central range the dynamic force that has been driving the exhumed crust is identified by results from focal mechanisms structural geology and geodetic survey in the eastern central range such a tectonic model may provide a good explanation for the evolution of the taiwan orogeny as well as an active case for studying other long extinct systems of continental subduction and exhumation

geochemistry and skeletal structure of diploria strigosa implications for coral based climate reconstruction abstract geochemical tracers incorporated into the skeleton of reef building corals are ideal proxies for reconstructing environmental parameters of ambient seawater such as temperature and salinity at subseasonal resolution however validation concerns of these environmental proxies due to the complex skeleton of some tropical atlantic corals have hindered such coral based environmental reconstructions in this region compared to the tropical pacific in order to identify complications associated with the complex skeletal architecture of the massive brain coral diploria strigosa we performed microsampling experiments along and across individual skeletal elements we demonstrate that the mesoscale heterogeneity of sr ca 18o and 13c is a systematic feature of d strigosa and is linked to different vital effects between skeletal elements the thecal wall is significantly depleted in sr 18o and 13c compared to the adjacent septa and columella and differences between apparent temperature signatures of several degrees are greater for sr ca suggesting that this temperature proxy is more sensitive to skeletal mixing than 18o parallel subseasonal microsampling experiments performed along individual skeletal elements of a single corallite of a d strigosa coral which grew at a rate of 0 65 cm year allow for investigating potential biases associated with its complex skeletal mesoarchitecture highest correlation between sr ca and 18o from skeletal material retrieved from the centre of the thecal wall suggests that microdrilling the theca provides the best environmental signal compared to adjacent microsampling profiles moreover based on monthly mean climatology the temperature dependence of sr ca for this profile is comparable to previous calibrations published from faster growing d strigosa based on these results we conclude that accurate microsampling along the centre of the thecal wall of d strigosa is a prerequisite for generating robust climate reconstructions from its skeleton

the 13c suess effect in scleractinian corals mirror changes in the anthropogenic co2 inventory of the surface oceans 1 new 13 c data are presented from 10 coral skeletons collected from florida and elsewhere in the caribbean dominica dominican republic puerto rico and belize these corals range from 96 to 200 years in age and were collected between 1976 and 2002 the change in the 13 c of the skeletons from these corals between 1900 and 1990 has been compared with 27 other published coral records from the atlantic pacific and indian oceans the new data presented here make possible for the first time a global comparison of rates of change in the 13 c value of coral skeletons of these records 64 show a statistically significant p 0 05 decrease in 13 c towards the modem day 23 out of 37 this decrease is attributable to the addition of anthropogenically derived co 2 13 c suess effect to the atmosphere between 1900 and 1990 the average rate of change of the 13 c in all the coral skeletons living under open oceanic conditions is approximately 0 01 o yr 1 in the atlantic ocean the magnitude of the decrease since 1960 0 019 yr 1 0 015 is essentially the same as the decrease in the 13 c of atmospheric co 2 and the 13 c of the oceanic dissolved inorganic carbon 0 023 to 0 029 yr 1 while in the pacific and indian oceans the rate is more variable and significantly reduced 0 007 yr 1 0 013 these data strongly support the notion that i the 13 c of the atmosphere controls ambient 13 c of the dissolved inorganic carbon which in turn is reflected in the coral skeletons ii the rate of decline in the coral skeletons is higher in oceans with a greater anthropogenic co 2 inventory in the surface oceans iii the rate of 13 c decline is accelerating superimposed on these secular variations are controls on the 13 c in the skeleton governed by growth rate insolation and local water masses

south china sea surface water evolution over the last 12 myr a south north comparison from ocean drilling program sites 1143 and 1146 1 planktonic foraminifera pf from ocean drilling program odp sites 1143 and 1146 in the southern and northern south china sea scs respectively were quantitatively analyzed in order to reconstruct the sea surface environment over the last 12 myr the observed decrease in deep dwelling pf species after 10 ma at both sites is interpreted to reflect a depression of the upper water thermocline corresponding to the closure of the indonesian seaway around 11 9 ma this upper water column structure implies the intensification of equatorial pacific warm currents and the initial formation of the western pacific warm pool wpwp during the early late miocene the consistent pattern of south north thermocline evolution and the synchronous disappearance of globoquadrina dehiscens 9 8 ma at both sites 1143 and 1146 together imply that the entire scs was likely under the influence of the newly developed wpwp at 10 ma after 8 ma sea surface temperatures and thermocline variations evolved differently between the southern and northern scs the total deep dwelling pf fauna at site 1143 decreased gradually in abundance from 6 6 to 2 ma indicating a deepening of the thermocline in the southern scs in contrast deep dwelling pf species increased in abundance from 3 1 to 2 ma at site 1146 reflecting a shoaling of the thermocline in the northern scs this south north contrast reflects two major environmental regimes 1 the southern scs which has mainly been under the influence of the wpwp since the late late miocene and 2 the northern scs where effects of the east asian winter monsoon have prevailed especially since the late pliocene estimate of past sea surface temperatures ssts at site 1143 suggests a relatively stable and warm environment in the southern scs since about 2 5 ma with an increased influence of warm subsurface waters after the mid pleistocene transition 1 2 0 9 ma in the northern scs however a gradual decrease in winter sst recorded at site 1146 over the last 4 myr records east asian monsoon evolution especially the enhancement of the east asian winter monsoon between 3 1 and 2 ma

the taiwan ryukyu subduction collision complex folding of a viscoelastic slab and the double seismic zone 1 the termination of the ryukyu trench against eurasia and the oblique subduction of the philippine sea plate create a subduction collision complex offshore taiwan which has not previously been elucidated in detail we combine traveltime data from the seismic networks in taiwan and japan to better illuminate how the subducting ryukyu slab deforms in this subduction collision zone more than 5000 events recorded by both networks were relocated with the double difference method using an optimal regional one dimensional velocity model the offshore seismicity indicates that the double seismic zone with a gap of 15 20 km exists in the subducting slab in the depth range of 40 80 km focal mechanisms suggest that the double seismic zone is caused by east west compression resulting from oblique convergence the improved hypocentral locations for the first time reveal folding of the slab into a horizontal curvature larger in magnitude than and opposite in sign to that of the ryukyu trench in the depth range 50 100 km the anomalous curvature together with the focal mechanisms suggests that the slab folds against the eurasian lithosphere and that this deformation cannot be fully elastic we model this deformation mode as the developing instability of a viscoelastic maxwell layer embedded in a viscous medium the characteristic wavelength of the instability i e 250 km is consistent with folding of a slab whose viscosity is 100 times higher than that of the surrounding mantle for an along strike elastic membrane strain as small as 0 01 or more than 3 orders of magnitude higher if 5 elastic strain is allowed

interdecadal decadal climate variability from multicoral oxygen isotope records in the south pacific convergence zone region since 1650 a d 1 in the south pacific interdecadal decadal oceanic and atmospheric variability referred to as the interdecadal pacific oscillation ipo is most pronounced in the south pacific convergence zone spcz salinity front region here we have used annual average oxygen isotope 18o time series from five coral cores collected from fiji and tonga in this region to construct a fiji tonga interdecadal decadal pacific oscillation f t idpo index of low frequency 9 and 55 years climate variability back to 1650 a d we first demonstrate the consistency between this f t idpo index and a mean sea level msl pressure based spcz position index spi 1891 2000 thus verifying the ability of coral 18o to record past interdecadal decadal climatic variations in this region back to 1891 the f t idpo index is then shown to be synchronous with the ipo index 1856 2000 suggesting that this coral based index effectively represents the interdecadal decadal scale climate variance back to 1650 the regularity of the f t idpo index indicates that interdecadal decadal variability in the spcz region has been relatively constant over the past 350 years with a mean frequency of 20 years variance peaks near 11 and 35 years there is a consistent antiphase correlation of the f t idpo index and the interdecadal decadal components in equatorial pacific coral 18o series from maiana and palmyra this observation indicates that the eastward expansion westward contraction of the eastern salinity front of the western pacific warm pool wpwp occurs simultaneously 1 year with the westward eastward shift of the spcz salinity front during positive ipo negative ipo phases this is the same relationship observed during the phases of the el nino southern oscillation

oxygen isotope systematics in diploastrea heliopora new coral archive of tropical paleoclimate diploastrea heliopora forms dense robust dome shaped coral colonies throughout the reef ecosystems of the tropical pacific and indian oceans this slow growing 2 to 6 mm yr coral has the potential to yield continuous paleoclimate records spanning up to 1000 yr for the warmest waters on earth the indo pacific warm pool and has a long fossil history as a single recognizable species despite the potential of diploastrea to be an important new paleoclimate archive little is known about the systematics of geochemical tracers incorporated into its skeleton to fill this knowledge gap we compared skeletal delta 18 o signatures in live diploastrea and porites colonies from southwest lagoon near amedee lighthouse new caledonia at the southern latitudinal limit for diploastrea and alor indonesia in the core area of the indo pacific warm pool we designed a new microsampling technique to minimize smoothing and distortion of the isotopic records due to the complex calyx architecture and slow growth of diploastrea high resolution isotope profiles from the septal portion of the diploastrea corallite are attenuated whereas those restricted to the central columella are similar in quality to those extracted from the well established porites coral archive the delta 18 o temperature relationship for the columellar portion of diploastrea 0 18parts per thousand degreesc is in good agreement with that derived for a nearby porites 0 19parts per thousand degreesc quinn et al 1996 on the basis of comparison with an in situ sea surface temperature record from amedee lighthouse there is a measurable difference of 0 3 0 1parts per thousand between the kinetic biological disequilibrium offsets from seawater delta 18 o composition for diploastrea and porites despite this offset in mean delta 18 o diploastrea accurately records the regional differences in mean temperature and salinity between new caledonia and the indo pacific warm pool additional tests show that diploastrea records el nino southern oscillation enso interannual variability in sea surface temperature and salinity across the southwestern pacific indicating that it should yield dependable paleo enso records based on these results we propose that d heliopora has the potential to provide an important new coral archive of tropical paleoclimate c copyright 2003 elsevier science ltd

seasonal and enso variations of sea surface salinity and temperature in the south pacific convergence zone during 1976 2000 1 sea surface salinity sss and temperature sst data collected from voluntary observing ships over 25 years 1976 2000 are analyzed in the southwestern tropical pacific 10 s 24 s 160 e 140 w this region lies under the south pacific convergence zone spcz at the southern edge of the western pacific warm pool between tahiti and darwin the two places whose atmospheric sea level pressure difference is used to define the southern oscillation index soi complementary data such as precipitation are used to assist in the analysis the mean and seasonal variations of these parameters are described an empirical orthogonal function eof analysis of low pass filtered time series is then performed to extract the interannual variability all parameters show an interannual signal which correlates well with the soi the southwestern tropical pacific ocean is saltier and colder during el nino than during la nina events in the southwestern part there is a shortage excess in precipitation during el nino la nina events the greatest anomalies appeared during the last la nina in 1996 and 1999 as regards sst and in 1999 and 2000 as regards sss sst and precipitation el nino southern oscillation enso related anomalies are an order of magnitude smaller than seasonal anomalies while the sss enso related signal is twice as strong as the seasonal signal these facts reflect the northeastward southwestward shift of the spcz during el nino la nina events while consistent with precipitation changes the enso related variability in sss can also be partly explained by the displacement of the salinity front that separates fresh warm pool waters from salty subtropical waters computation of surface geostrophic current anomalies from geosat 1987 1988 and topex poseidon 1993 2000 indicates that westward current anomalies developed during the 1987 88 and 1997 98 el nino and are linked to the displacement of the salinity front the southwestern tropical pacific salinity front moves westward eastward in contrast to the equatorial salinity front which moves eastward westward during an el nino la nina event

geochemistry based coral palaeoclimate studies and the potential of non traditional non massive porites corals recent developments and future progression understanding the natural variability of the earth s climate system and accurately identifying potential anthropogenic influences requires long term geographically distributed records of key climate indicators such as temperature and precipitation that extend prior to the last 400 years of the holocene reef corals provide an excellent source of high resolution climate records and importantly represent the tropical marine environment where palaeoclimate data are urgently required recent decades have seen significant improvement in our understanding of coral biomineralisation the associated uptake of geochemical proxies and methods of identifying and understanding the effects of both early and late post depositional diagenetic alteration these processes all have significant implications for interpreting geochemical proxies relevant to palaeoclimatic reconstructions this paper reviews the current state of the art in terms of coral based palaeoclimate reconstructions and highlights a key remaining problem the majority of coral based palaeoclimate research has been derived from massive colonies of porites however massive porites are not globally abundant and may not provide material of a particular age of interest in those regions where they are present therefore there is great potential for alternate coral genera to act as complimentary climate archives while it remains critical to consider five key factors vital effects differential growth morphologies geochemical heterogeneity in the skeletal ultrastructure transfer equation selection and diagenetic screening of skeletal material in order to allow the highest level of accuracy in coral palaeoclimate reconstructions it is also important to develop alternate taxa for palaeoclimate studies in regions where porites colonies are absent or rare currently as many as nine genera other than porites have proven at least limited utility in palaeothermometry most of which are found in the atlantic caribbean region where massive porites do not exist even branching taxa such as acropora have significant potential to preserve environmental archives increasing this capability will greatly expand the number of potential geochemical archives available for longer term temporal records of palaeoclimate

interaction between the enso and the asian monsoon in a coral record of tropical climate the oxygen isotopic composition of a banded coral from the western equatorial indian ocean provides a 150 year long history of the relation between the el nino southern oscillation enso phenomenon and the asian monsoon interannual cycles in the coral time series were found to correlate with pacific coral and instrumental climate records suggesting a consistent linkage across ocean basins despite the changing frequency and amplitude of the enso however decadal variability that is characteristic of the monsoon system also dominates the coral record which implies important interactions between tropical and midlatitude climate variability one prominent manifestation of this interaction is the strong amplitude modulation of the quasi biennial cycle

diploastrea heliopora sr ca and δ18o records from northeast luzon philippines an assessment of interspecies coral proxy calibrations and climate controls of sea surface temperature and salinity

relative influences of the interdecadal pacific oscillation and enso on the south pacific convergence zone 1 the south pacific convergence zone spcz one of the most extensive features of the global atmospheric circulation is shown to vary its location according to both the polarity of the el nino southern oscillation enso and of the interdecadal pacific oscillation ipo we first demonstrate that the ipo can be regarded as the quasi symmetric pacific wide manifestation of the pacific decadal oscillation that has been described for the north pacific shifts in the position of the spcz related to enso on interannual time scales and to the ipo on decadal time scales appear to be of similar magnitude and are largely linearly independent a station pressure based index of variations in spcz latitude is shown to be significantly related to the polarity of the ipo when enso influences are accounted for movements of this sensitive section of the spcz have occurred in phase with those of the ipo since the 1890s

a review of modern coral δ18o and δ14c proxy records abstract this paper is a review of published modern coral 18 o and 14 c isotopic records that are at least 30 and 20 years long respectively the data are presented to show basin scale trends in both of these proxy records on decadal to centennial timescales the goal was to qualitatively integrate the general inter annual to centennial timescale variability revealed in these data as well as the statistical and modeling output results that have been produced using these coral records while many review papers typically include a representative subset of the data available this review aims to include as much of the available data as possible in general coral 18 o records show a long term warming and or freshening throughout the tropical oceans and agree with the noaa extended reconstruction sea surface temperature 2 ersst on decadal timescales in the western pacific it is most likely a freshening of the seawater 18 o that dominates the signal el nino southern oscillation enso variability dominates most 18 o records either by varying local seawater temperature or salinity depending on the regional oceanography climatology outside of the pacific enso affects seawater temperature and salinity via atmospheric or oceanic teleconnections post bomb coral 14 c records collectively show that the uptake of 14 c has been greatest in gyre water fed sites followed in descending order by western boundary current areas equatorial upwelling regions and eastern tropical pacific upwelling sites these surface water 14 c values indicate the proportion of surface water and or the residence time of water at the surface at a given location and can be used to model water mass mixing rates such models have only begun to be run and show that the amount of eastern pacific water entering the central south pacific increases during el ninos and that the indonesian throughflow is supplied year round by the north pacific comparing ocean circulation models with coral 14 c modelled circulation enables researchers to explore the mechanisms that drive seawater 14 c variability and fine tune their models in addition our comparison between the rate of coral 14 c increase between 1960 and 1970 and total anthropogenic co 2 uptake rates show general agreement demonstrating the value of coral records in understanding past carbon fluxes overall coral 18 o and 14 c proxy records represent natural archives of seawater conditions and are critical for studying the natural variability in local and regional patterns within and teleconnection patterns between the tropics extra tropics temperate and polar regions on intra annual to centennial timescales

refining temperature reconstructions with the atlantic coral siderastrea siderea abstract developing coral based temperature reconstructions for a particular coral species requires determining the optimal sampling path orientation and resolution for geochemical analysis to avoid sampling artifacts and to increase reproducibility furthermore a robust coral archive should have high intracolony and intercolony reproducibility for determining the common environmental signal here we assessed sampling path orientation and sampling resolution for siderastrea siderea colonies within the dry tortugas national park in the gulf of mexico 24 42 n 82 48 w to determine the optimal sampling protocol and to assess reproducibility of coral sr ca 18o and 13c we identified a sampling artifact due to extracting samples from the coral columella resulting in cold bias up to 5 2 c in coral sr ca we found no shift to higher coral sr ca values i e colder for years with a 50 reduction in average extension rate 2 1 mm year 1 or for sampling along paths up to 70 off the vertical axis of the colony our sampling resolution comparison 1900 1993 indicated that the resolution of 6 samples year 1 used in a previous study for coral sr ca and 18o may not capture seasonal extremes and thus produces muted seasonal cycles but that resolution is not biased towards one season reproducibility or average deviations assessed using absolute differences ad and root mean square rms among the monthly resolved coral sr ca records for intracolony to intercolony comparisons were within 2 of our analytical precisions average deviations were reduced by 19 to 61 when assessing interannual variability 36 month smoothed and mean annual suggesting that subannual dating uncertainties i e assigning a coral sr ca value to a particular month were the largest source of error in our monthly resolved coral sr ca reconstruction similarly coral 18o was reproducible within 2 of our analytical precision ad 0 10 and rms 0 07 however coral 13c and linear extension records were not reproducible our assessment of coral geochemical variations from multiple s siderea colonies suggests this species is suitable for paleoclimatic reconstructions including subfossil corals and microatoll colonies that grow laterally

propagation of high frequency seismic waves inside the subducted lithosphere from intermediate depth earthquakes recorded in the vanuatu arc three seismic phases associated with the slab of subducted lithosphere are identified on seismograms of intermediate depth earthquakes depths 70 km recorded in the distance range up to 350 km by the vanuatu formerly new hebrides seismograph network they are interpreted as 1 a p wave refracting into the inner portion of the slab 2 a p wave traveling mainly through the outer upper portion of the slab and 3 a p to s converted wave in which the conversion occurs across the upper surface of the slab the existence of the two p arrivals from intermediate depth earthquakes suggests that these earthquakes are not located in the strong and cold inner core of the slab but within an outer zone where the velocity is lower than that within the inner portion of the slab the low frequency character of the shear wave converted from the p wave across the outer boundary of the slab indicates that either the boundary is a transition layer with a finite thickness or the material above the slab has high attenuation for high frequency shear waves large spatial variations in the transmission of high frequency shear waves also indicate that there is a localized zone of anomalous shear wave attenuation in the mantle wedge lying just above the subducted slab and beneath the active volcanos

calcite graphite thermometry of the franklin marble new jersey highlands abstract we present new stable isotope data for the mesoproterozoic franklin marble from outcrops along an 80 km traverse parallel to and across strike of the structural grain of the western new jersey highlands calcite and dolomite from marble have an average 13c of documentclass aastex usepackage amsbsy usepackage amsfonts usepackage amssymb usepackage bm usepackage mathrsfs usepackage pifont usepackage stmaryrd usepackage textcomp usepackage portland xspace usepackage amsmath amsxtra usepackage ot2 ot1 fontenc newcommand cyr renewcommand rmdefault wncyr renewcommand sfdefault wncyss renewcommand encodingdefault ot2 normalfont selectfont declaretextfontcommand textcyr cyr pagestyle empty declaremathsizes 10 9 7 6 begin document landscape 0 35 mbox textperthousand pm 0 73 mbox textperthousand end document pdb documentclass aastex usepackage amsbsy usepackage amsfonts usepackage amssymb usepackage bm usepackage mathrsfs usepacka

rapid analysis of high precision sr ca ratios in corals and other marine carbonates a method for rapid determination of high precision sr ca ratios in scleractinian corals is presented using an inductively coupled plasma atomic emission spectrophotometer samples are corrected for instrument drift using a reference solution similar to the approach used for analysis of stable isotopes using gas source mass spectrometry further correction for variation of the sr ca ratio with ca concentration is accomplished using internal standards the precision once all corrections have been made is better than 0 1 relative standard deviation 1 for samples of similar ca concentration and better than 0 2 for samples with variable ca concentrations this method increases the sample throughput by approximately a factor of 20 relative to thermal ionization mass spectrometry and significantly reduces instrument and per sample costs comparison of sr ca data for a coral from the galapagos islands with an instrumental temperature record shows excellent agreement and demonstrates the potential for application of this technique to samples of modern and fossil scleractinian corals and other marine carbonates including foraminifera

subducting oceanic crust on the philippine sea plate in southwest japan abstract it is well known that subcrustal earthquakes occur in southwest japan owing to subduction of the philippine sea phs plate observing the earthquakes at a single station in the chugoku district we frequently find a distinct pair of later p and s phases after weak initial p and s phases respectively these later phases were observed only for earthquakes with particular source receiver geometries the events in the west seto inland sea epicentral distances from 120 km to 240 km and the source receiver direction almost parallel to the strike of the nankai trough the feature of initial and later phases was summarized as follows 1 the later phases are observed for subcrustal earthquakes occurring at depths between 40 km and 60 km but not for those below the depth 2 single station apparent velocities of initial p and s phases are 8 0 km s and 4 9 km s and they are somewhat higher than ordinary velocities of the uppermost mantle 3 single station apparent velocities of later p and s phases are on the other hand 6 6 km s and 3 8 km s and they are comparable to the velocities of the continental lower crust and the main layer of oceanic crust these features could not be explained unless the subcrustal earthquakes take place within the low velocity oceanic crust overlying the high velocity oceanic plate this suggests that the oceanic crust subducts beneath the west seto inland sea as a part of the phs plate

calibration of stable oxygen isotopes in siderastrea radians cnidaria scleractinia implications for slow growing corals geochemical proxies in the skeletons of corals used for the purpose of reconstructing environmental records have typically been obtained from relatively fast growing corals usually 8 mm yr 1 and from only a few key genera most commonly porites and montastraea in many areas however there are no suitable fast growing corals available for such reconstructions here we investigate the potential of siderastrea radians a slow growing atlantic and caribbean zooxanthellate coral as an archive of sea surface temperature sst and salinity over the period from 1891 to 2002 sampling the skeleton of three corals from the cape verde islands we were able to reproduce a clear seasonal signal but with limited correlation to monthly sst arising from inadequate chronologic constraint of the individual samples the sst 18o calibration slopes for different sampling scales on several cores can range from about 9 c 1 to 2 c 1 compared to other published values of around 5 to 4 c 1 careful treatment produced a 18o sst calibration equation where sst c 12 56 1 20 3 86 0 39 c w the recognition of the limitations of calibration at such small growth rates due to skeletal complexity and suspicion of environmental interferences suggests the need for careful consideration in the interpretation of climate proxy results from s radians and other slow growing corals

high resolution isotopic records from corals using ocean temperature and mass spawning chronometers abstract we present a 6 year long 1978 1984 18 o and 13 c record from a great barrier reef pandora reef porites lutea coral based on near weekly sample intervals a sampling technique was designed to minimise any smoothing or distortion of the isotopic record due to complex coral growth calyx architecture and calcification at depth within the tissue layer the arrival time of the mid winter minimum sea surface temperature is very consistent 2 weeks near pandora reef and provides an annual time marker offering more precision than the traditional density band chronometer the improved chronology and high resolution record demonstrate that signal distortion in porites due to calcification within the tissue layer and variable intra annual coral extension is generally negligible also confirmed is that the arrival time of monsoonal floods is precisely preserved 1 week within the skeleton of porites the sensitivity of weekly sampling allows the detection of a subtle warm to cool sea surface temperature anomaly which preceded by more than one year a similar temperature anomaly associated with the 1982 83 el nin o in the east pacific sharply higher 13 c values coincide with the time of the annual coral mass spawning event in the great barrier reef recognition of this mass spawning signal should simplify the interpretation of coral 13 c records and provides an additional precise time marker with which to adjust chronologies when intra annual coral extension is not constant

el nino southern oscillation enso and decadal scale climate variability at 10 n in the eastern pacific from 1893 to 1994 a coral based reconstruction from clipperton atoll we have developed a 101 year 1893 1994 subseasonal oxygen 18o and carbon 13c isotopic time series from clipperton atoll in the eastern pacific using the coral porites lobata in agreement with linsley et al 1999 we find that seasonal and interannual coral 18o variability at clipperton results from variability in both water temperature and salinity three new coral time series demonstrate the reproducibility of a secular coral 18o trend of 0 35 since 1910 but show varying 13c trends strong decadal scale variability in the 18o record appears related to the pacific decadal oscillation pdo through postulated changes in the strengths of the equatorial counter current and north equatorial current interannual variability in this coral 18o record is directly related to the el nino southern oscillation enso and isolation of this frequency band indicates reduced enso variability in the eastern equatorial pacific in the period 1925 to 1940 in agreement with instrumental and other pacific coral records

quantifying errors in coral based enso estimates toward improved forward modeling of δ18o 1 the oxygen isotopic ratio 18o in tropical pacific coral skeletons reflects past el nino southern oscillation enso variability but the 18o enso relationship is poorly quantified uncertainties arise when constructing 18o data sets combining records from different sites and converting between 18o and sea surface temperature sst and salinity sss here we use seasonally resolved 18o from 1958 to 1985 at 15 tropical pacific sites to estimate these errors and evaluate possible improvements observational uncertainties from kiritimati new caledonia and rarotonga are 0 12 0 14 leading to errors of 8 25 on the typical 18o variance multicoral syntheses using five to seven sites capture the principal components pcs well but site selection dramatically influences enso spatial structure using sites in the eastern pacific western pacific warm pool and south pacific convergence zone spcz captures eastern pacific type variability while central pacific type events are best observed by combining sites in the warm pool and spcz the major obstacle to quantitative enso estimation is the 18o climate conversion demonstrated by the large errors on both 18o variance and the amplitude of the first principal component resulting from the use of commonly employed bivariate formulae to relate sst and sss to 18o errors likely arise from either the instrumental data used for pseudoproxy calibration or influences from other processes 18o advection atmospheric fractionation etc at some sites modeling seasonal changes to these influences reduces conversion errors by up to 20 this indicates that understanding of past enso dynamics using coral 18o could be greatly advanced by improving 18o forward models

taiwan orogeny thin skinned or lithospheric collision abstract the taiwan orogeny is young and presently very active it provides an excellent environment for studying ongoing orogenic processes especially since the region is monitored intensively with dense seismological and geodetic networks and new studies aiming at deciphering shallow and deep structures in and around taiwan have been recently conducted or are being planned the available data can be used continually to test critically hypotheses of the taiwan orogeny hypotheses dealing with the mechanics of mountain building are basic to the understanding of taiwan orogeny and are particularly amenable to testing the widely cited thin skinned tectonics hypothesis was formulated to explain mainly the geologic and relatively shallow

seismological constraints on the gabbro eclogite transition in subducted oceanic crust abstract dispersion of seismic waves travelling along the strike of the subducted pacific plate beneath tonga kermadec shows evidence for a high velocity layer of crustal thickness extending to a depth of at least 450 km the opposite dispersion with low frequencies arriving first is observed in japan and has been taken together with inferences from converted phases as evidence of a thin low velocity layer both layers have in previous studies been interpreted as subducted oceanic crust which has been transformed to eclogite but in tonga kermadec the eclogite must have high seismic velocity and beneath japan it must have a low seismic velocity an apparent contradiction therefore exists here we find theoretical estimates of the seismic velocities of eclogite and normal mantle using the data and equations of duffy and anderson and a variety of mineral assemblages and bulk compositions we find a range of both low and high seismic velocities the high end of the range depending mainly on the contents of jadeite pyrope and grossular it is therefore possible in principle to explain both the high velocity layer beneath tonga kermadec and the low velocity layer beneath japan as being consistent with an eclogitic crust provided they have significantly different compositions however we can find no clear reason for such a difference between that part of the pacific plate currently subducting beneath japan and that beneath tonga kermadec

evaluating the use of the massive coral diploastrea heliopora for paleoclimate reconstruction 1 to date coral based paleoclimate research in the pacific has primarily utilized core samples from the genus porites and has been most successful reconstructing past variability on interannual timescales particularly the el nino southern oscillation enso the indo pacific coral genus diploastrea however owing to its slower extension rate denser structure and longer lifespan can potentially preserve geochemical proxy records 2 3 times longer than porites cores of the same length before its potential can be realized diploastrea must first be calibrated and its climate signal assessed we present oxygen isotope 18o and sr ca results from two diploastrea cores collected in fiji 16 49 s 179 14 e that allow for simultaneous evaluation of this coral s paleoclimatic utility and the reproducibility of each tracer at this site comparison to a porites record from the same location allows for further evaluation of diploastrea as a paleoclimatic archive we demonstrate that diploastrea s septal and columellar material yield similar 18o sst relationships and that despite some sacrifice of the seasonal 18o amplitude bulk sampling of either region is satisfactory for resolving interannual and lower frequency modes of climatic variability therefore paleoclimate reconstructions employing either a septal or columellar sampling regime of this genus may be useful at filling in spatial and temporal sampling gaps which currently hinder the reconstruction of long term changes in major climate fields in the western pacific

eastern pacific sea surface temperature since 1600 a d the δ18o record of climate variability in galapagos corals we measured stable oxygen isotope ratios and skeletal growth rates in the massive corals pavona clavus and p gigantea from the west coast of isabela island galapagos to assess interannual to decadal climate variability in the eastern pacific comparisons of instrumental data sets show that sea surface temperatures sst in the galapagos region are representative of a broad portion of the eastern equatorial pacific the site is especially well suited for long term studies of the el nino southern oscillation enso phenomenon as it lies within the eastern pacific center of action for thermal anomalies associated with enso the p gigantea isotope record is nearly monthly in resolution spans the period 1961 1982 and shows strong correlation with a galapagos instrumental sst record r 0 90 for annual averages cross spectral analysis shows that sst can explain greater than 80 of the variance in 18o at both the annual cycle and within the high frequency portion of the enso band 3 5 years the p clavus record is annual in resolution extends from 1587 to 1953 a d and was obtained from a 10 m diameter colony preserved within the urvina bay uplift because seawater 18o variations in the region are very small we interpret the urvina bay coral 18o record in terms of annual average sst the isotopic record appears to be a very good but not perfect indicator of enso events and shows good correspondence with the historical enso reconstruction of quinn et al 1987 a number of low 18o excursions that we observe during the 17th and 18th centuries very likely represent enso events that are missing from the historical tabulations most interannual 18o variations between 1607 and 1953 a d represent annual average temperature excursions of 1 to 2 5 c during the little ice age the annual 18o series correlates well with many north american tree ring records and shows low temperatures during the early 1600s and early 1800s and relatively warmer conditions during the 1700s unlike most northern hemisphere tree ring and instrumental records we see no evidence at this site for warming between 1880 and 1940 but rather observe a slight cooling 28 of the total variance the main enso mode is centered at 4 6 years and accounts for 12 of the total variance additional significant oscillations occur at periods of 3 3 6 8 11 17 22 and 34 years both annual growth rate and 18o show variance at periods equivalent to the solar and solar magnetic periods e g 11 and 22 years respectively in addition the amplitude of the 11 year 18o cycle generally varies with the amplitude of the solar cycle supporting previous suggestions that the solar cycle may modulate interannual to decadal climate variability in the tropics the dominant oscillatory modes both within the enso and interdecadal frequency bands shift to shorter periods from the early to middle 1700s and again from the middle to late 1800s this may reflect major reorganizations within the tropical ocean atmosphere system and suggests that tropical pacific climate variability is linked across timescales ranging from years to decades

fast p wave propagation in subducted pacific lithosphere refraction from the plate p waves traveling from events in the tonga kermadec seismic zone to stations in new zealand are very fast with highly emergent dispersed waveforms ray tracing has shown the waves to travel close to the subducted pacific plate throughout their length and synthetic seismogram calculations have shown the dispersion requires a very thin 8 12 km fast layer previous work has been based on data from analogue records and one digital single component short period instrument no polarization analysis was possible and measurements of dispersion were limited by the bandwidth from january 1991 to august 1992 we deployed nine broad band three component seismometers in good sites for observing these arrivals the data are augmented by three component short period digital records from new stations of the new zealand national network in this study we analyze 1191 broad band and 2076 short period seismograms from 71 events for polarization of the initial p wave the polarization directions are found to be up to 30 off the great circle path and consistently steep 20 from vertical they are too steep to be explained by standard ray paths or refraction from a fast horizontal layer we invert the polarization directions for a tilted interface beneath the array and use arrival times to control the depth to the interface which is found to lie close to the top of the subducted plate inferred from the seismicity we conclude that these precursive emergent p waves have traveled through a fast layer close to the top of the subducted plate and refract upward to the station a second arrival with lower dominant frequency near 1 hz and normal travel time is occasionally seen on both broad band and short period stations its polarization direction is similarly steep but difficult to measure the evidence suggests that it also travels within the plate with similar ray path to the precursor

dispersion of regional body waves at 100 150 km depth beneath alaska in situ constraints on metamorphism of subducted crust phase delays at high frequencies are observed in body waves that travel in the alaska slab along its strike at 100 150 km depth the delays between 2 6 hz energy and the direct 0 5 1 hz arrival are 0 5 1 5 s for p waves and 1 5 4 s for s waves such dispersion suggests a waveguide structure that parallels the slab perhaps near its top a channel that is 2 6 km thick and 2 5 5 slower than surrounding mantle can explain the observations the thickness of the layer is comparable to that of subducted oceanic crust or somewhat thinner the layer may be crust that is slow at these depths the required velocity anomaly is too small to be due to a continuous layer of metastable gabbro yet too large to represent an eclogite layer it may indicate a mixture of the two or persistence of hydrated mineral assemblages to depth

a 173 year stable isotope record from a tropical south pacific coral 0 we have generated a 173 year long time series a d 1806 to 1979 of changes in the 18 o and 13 c composition of a coral head platygyra lamellina to investigate environmental change in the climatologically sensitive region of the tropical south pacific little is known about decadal and centennial scale climate change at sea level in this region our coral is from near the south coast of espiritu santo island 15 s 167 e republic of vanuatu the stable isotope record from this coral is consistent with meteorological and oceanographic records during the period of overlap in the records 1964 1978 18 o values positively correlate with sst r 0 77 and 13 c values are highly coherent with rainfall r 0 82 at the annual cycle these relations suggest that the 18 o signal in this coral is a function of variations in sst and rainfall induced changes in sss whereas the 13 c signal may be related to rainfall and cloud cover modulation of photosynthesis in the coral 18 o and 13 c values are positively correlated over the entire length of the record r 0 65 a relation that is even stronger between 1806 and 1866 r 0 81 i e prior to the time of possible anthropogenic influence on the 13 c record because of the positive correlation between temperature and rainfall in this region we interpret the long term record of 18 o in terms of joint variations of these two variables the most significant cool dry excursion in the santo record occurs during the nineteenth century 1832 1866 and ends abruptly in 1866 with a change to modern values superimposed on this pattern is a slight 0 2 cooling drying toward the end of the twentieth century cross spectral analysis of the 18 o and 13 c records indicates a strong concentration of variance at the quasi biennial 2 years and el nino southern oscillation enso 4 5 years frequency bands in addition to a 15 year peak found also in global temperature records cross spectral analysis of coral isotope records from santo and the philippine sea indicate a concentration of variance at enso 4 5 years frequency bands however comparison of the santo coral isotope record with high latitude northern hemisphere temperature records indicates that the major cool dry excursion in the santo record 1832 1866 is not seen in the northern hemisphere record if verified in other tropical south pacific coral records the results have implications concerning the global scale of cooling for little ice age events

seismic evidence for deep water transportation in the mantle we report seismic evidence for the transportation of water into the deep mantle in the subduction zone beneath northeastern japan our data indicate that water is released from the hydrated oceanic crust at shallow depths approximately 100 kilometers and then forms a channel of hydrated mantle material on top of the subducting plate that is the pathway for water into the deep mantle our result provides direct evidence that shows how water is transported from the ocean to the deep mantle in a cold subduction zone environment

a synthesis of the geologic evolution of taiwan abstract the island arc of taiwan is composed of cenozoic geosynclinal sediments more than 10 000 m thick lying on a pre tertiary metamorphic basement pleistocene to miocene andesitic islands surround the main island and are related mostly to arc magmatism the penghu island group in the taiwan strait is covered with pleistocene flood basalt neogene shallow marine clastic sediments are exposed mainly in the western foothills with pleistocene andesitic extrusives at the northern tip and the northeastern offshore islands a thick sequence of paleogene to miocene argillitic to slaty metaclastic rocks underlies the western central range and forms the immediate sedimentary cover on the pre tertiary metamorphic complex to the east which represents an older mesozoic arc trench system the coastal range in eastern taiwan is a neogene andesitic magmatic arc including also a large variety of volcaniclastic and turbiditic sediments cenozoic taiwan is the site of arc continent collision where the luzon arc on the philippine sea plate overrides the chinese continental margin on the eurasian plate east and northeast of taiwan the polarity of subduction changes whereby the oceanic philippine sea plate is subducting beneath the ryukyu arc system on the eurasian plate continent arc collision in taiwan island is anomalous and may occur in a broad belt of deformation rather than along a well defined plate boundary or subduction zone

improving coral base paleoclimate reconstructions by replicating 350years of coral sr ca variations abstract coral based climate reconstructions are typically based on a single record and this lack of replication leads to questions in regards to chronology accuracy and reliability of the inclusive geochemical variations to record climate viability here we present two multi century coral sr ca records recovered from a porites lutea colony offshore of amedee island new caledonia 22 28 8 s 166 27 9 e the chronology was developed by cross dating the coral sr ca time series and verifying the chronology with high precision absolute 230th dating we identify chronological discrepancies of 2 3 and 3 7 years century 1 for reconstructions based on a single core with uncertainty increasing after 250 years we assess the impact of porites skeletal architecture on coral geochemistry by characterizing centimeter scale architectural structures with respect to sampling optimal sampling paths are those on the slab surface parallel to the growth direction of individual corallites along the central axis of an actively extending corallite fan coral sr ca time series extracted from optimal skeletal structures are highly reproducible with a mean absolute difference of 0 021 mmol mol 1 or 0 39 c for monthly determinations suboptimal skeletal architecture is characterized by corallites extending through the slab surface and the coral sr ca determinations derived from suboptimal paths tend to produce a warm bias that varies between 0 04 and 2 30 c disorganized skeletal architecture is characterized by small terminating or unclear corallite fans that produce a cold bias of 0 11 to 2 45 c in coral sr ca determinations these problematic architecture types also produce biases in coral 18o determinations but to a lesser extent we assess the impact of sampling a coral colony along paths that vary from vertical to horizontal in large and small porites colonies with extension rates 6 mm year 1 and we determine there is no significant difference in the coral sr ca records

high frequency waves guided by the subducted plates underneath taiwan and their association with seismic intensity anomalies 1 energy from seismic events traveling up a subduction zone is frequently associated with significant large amplitude high frequency signals with sustained long coda such seismic waves guided by the subducted plate with high wave velocity and high q can cause surprisingly large seismic intensity in the fore arc area in this study we characterize the guiding behavior of the subducted philippine sea plate psp underneath taiwan and investigate their relationship with anomalous peak ground acceleration pga patterns obliquesubductionof philippine seaplatebeneathnortheast taiwan complicatestheguiding phenomena seismic waves from events deeper than 60km offshore northern taiwan reveal wave guide behavior large sustained high frequency 3 10hz signalinpandswavetrains with increasing depth a low frequency 1hz first arrival becomes more significant especially for events deeper than 100km the time separation between the low frequency onset and the later high frequency arrival slightly increases with depth while the value varies with station due to different travel distances in the shallow crust the depth dependent high frequency content confirms the association with a waveguide effect in the subducting slab rather than localized site amplification effects we attempt here to obtain a practicable quantification scheme to determine the duration of higher frequency energy which can be regarded as an indicator of the guiding effect of the philippine sea plate

record of little ice age sea surface temperatures at bermuda using a growth dependent calibration of coral sr ca 1 strontium to calcium ratios sr ca are reported for a massive brain coral diploria labyrinthiformis collected from the south shore of bermuda and are strongly correlated with both sea surface temperature sst and mean annual skeletal growth rate high sr ca ratios correspond with cold ssts and slow skeletal growth rate and vice versa we provide a quantitative calibration of sr ca to extension rate and sst along the axis of maximum growth and derive a growth dependent sr ca sst calibration equation to reconstruct western subtropical north atlantic ssts for the past 223 years when the influence of growth rate is excluded from the calibration sr ca ratios yield ssts that are too cold during cool anomalies and too warm during warm anomalies toward the end of the little ice age 1850 sst changes derived using a calibration that is not growth dependent are exaggerated by a factor of 2 relative to those from the growth corrected model that yields ssts 1 5 c cooler than today our results indicate that incorporation of growth rate effects into coral sr ca calibrations may improve the accuracy of ssts derived from living and fossil corals

a new articulated freshwater fish clupeomorpha ellimmichthyiformes from the horseshoe canyon formation maastrichtian of alberta canadathis article is one of a series of papers published in this special issue on the theme albertosaurus horseshoeichthys armaserratus gen et sp nov clupeomorpha ellimmichthyiformes sorbinichthyidae is described from the horseshoe canyon formation maastrichtian albertosaurus bonebed locality alberta canada horseshoeichthys armaserratus is classified as an ellimmichthyiform based on the following characters the presence of a sixth infraorbital with a sensory canal that leads to the fifth infraorbital absence of a supraorbital bone subrectangular predorsal scutes parietals in contact with each other at the midline and two supramaxillae the specimen is classified in the sorbinichthyidae family as it has abdominal ribs articulating in pits on the centra posterior spines on predorsal scutes and absence of a median spine on predorsal scutes a new genus and species is proposed based on the presence of anteriorly y shaped mesethmoid supraorbital subrectangular predorsal scutes with coarse rounded serrae on the posterior margin and a large anterior projection scales with serrae on the ci

decadal sea surface temperature variability in the subtropical south pacific from 1726 to 1997 a d we present a 271 year record of sr ca variability in a coral from rarotonga in the south pacific gyre calibration with monthly sea surface temperature sst from satellite and ship measurements made in a grid measuring 1 degrees by 1 degrees over the period from 1981 to 1997 indicates that this sr ca record is an excellent proxy for sst comparison with sst from ship measurements made since 1950 in a grid measuring 5 degrees by 5 degrees also shows that the sr ca data accurately record decadal changes in sst the entire sr ca record back to 1726 shows a distinct pattern of decadal variability with repeated decadal and interdecadal sst regime shifts greater than 0 75 degrees c comparison with decadal climate variability in the north pacific as represented by the pacific decadal oscillation index 1900 1997 indicates that several of the largest decadal scale sst variations at rarotonga are coherent with sst regime shifts in the north pacific this hemispheric symmetry suggests that tropical forcing may be an important factor in at least some of the decadal variability observed in the pacific ocean

evaluation of sampling resolution in coral stable isotope records a case study using records from new caledonia and tarawa we have generated a 40 year long monthly stable isotope record from a porites lutea coral collected offshore of amedee new caledonia 22 s 167 e to investigate the relation between sampling resolution in coral isotope studies and retrieval of sea surface environmental information we interpret the high correlation between our oxygen isotope record and a twenty year long sea surface temperature record at the monthly timescale r 0 88 to indicate that our coral isotope record is an accurate monitor of environmental conditions offshore of amedee the character of the signal and the percent variance explained in the record at the annual band at the quasi biennial oscillation band qbo 2 0 2 4 years and at the el nino southern oscillation band enso 3 8 years changes little in response to a reduction in sampling density from monthly to bimonthly to quarterly similar results have been obtained in a reanalysis of a coral isotope record from tarawa kiribati our results indicate that a significant amount of the information obtained from high density sampling can also be retrieved from lower density sampling in particular bimonthly sampling yields virtually no drop off in variance explained and quarterly sampling is satisfactory for resolving interannual and decadal scale trends in time series the proposed sampling approach may enable a more rapid filling in of numerous spatial holes in coral sampling sites needed for reconstruction of long term decadal scale variations in climate

refining the sampling approach for the massive coral diploastrea heliopora for δ 18 o based paleoclimate applications abstract studies on the indo pacific coral diploastrea have demonstrated that this genera can potentially be used to generate multi century length climate reconstructions however some concerns remain regarding sampling protocols this study further explores the utility of diploastrea heliopora for paleoclimatic reconstructions by examining 18 o along short coral cores of d heliopora and porites lutea from kandavu fiji these results indicate that sampling of the columellar part of the corallite in d heliopora is optimal to capture the full annual 18 o cycle and that bi monthly 0 5 mm sampling resolution is the optimal temporal resolution for the kandavu d heliopora results from kandavu d heliopora show high intra core reproducibility as well as a significant correlation to a 18 o record from a nearby porites colony monthly resolution r 0 71 n 186 df 54 p 0 01 annual resolution r 0 59 n 16 df 16 p 0 01 at our fiji study site d heliopora and porites skeletal 18 o have similar sensitivities to sea surface temperature and sea surface salinity validating the approach of using both coral species to create robust climate reconstructions these results indicate that microanalyses of the columellar portion of d heliopora skeleton produce time series 18 o results similar in quality to that extracted from porites

acropora interbranch skeleton sr ca ratios evaluation of a potential new high resolution paleothermometer the majority of coral geochemistry based paleoclimate reconstructions in the indo pacific are conducted on selectively cored colonies of massive porites this restriction to a single genus may make it difficult to amass the required paleoclimate data for studies that require deep reef coring techniques acropora however is a highly abundant coral genus in both modern and fossil reef systems and displays potential as a novel climate archive here we present a calibration study for sr ca ratios recovered from interbranch skeleton in corymbose acropora colonies from heron reef southern great barrier reef significant intercolony differences in absolute sr ca ratios were normalized by producing anomaly plots of both coral geochemistry and instrumental water temperature records weighted linear regression of these anomalies from the lagoon and fore reef slope provide a sensitivity of 0 05 mmol mol c 1 with a correlation coefficient r2 0 65 comparable to those of genera currently used in paleoclimate reconstructions reconstructions of lagoon and reef slope mean seasonality in water temperature accurately identify the greater seasonal amplitude observed in the lagoon of heron reef a longer calibration period is however required for reliable reconstructions of annual mean water temperatures

a multicoral calibration method to approximate a universal equation relating sr ca and growth rate to sea surface temperature 1 combining strontium to calcium ratios sr ca with mean annual growth rates in bermuda diploria labyrinthiformis brain corals is shown to improve sea surface temperature sst calibrations relative to instrumental data growth corrected sr ca sst calibrations based on single coral colonies over the same calibration interval however are found to be poorly suited for application to data from different coral colonies this raises concerns about the accuracy of sst reconstructions from fossil coral measurements that involve extrapolation beyond the range of values seen during the calibration period here we pursue a novel approach to this problem by incorporating data from multiple coral colonies into a single growth corrected sr ca sst calibration equation effectively expanding the range of modern values constraining the model the use of a multiple colony calibration model for reconstructing sst yields greater precision and accuracy relative to instrumental data than single colony models providing greater confidence for applications to fossil coral samples

a multicentury stable isotope record from a new caledonia coral interannual and decadal sea surface temperature variability in the southwest pacific since 1657 a d a 335 year stable isotope record from a new caledonia coral 22 s 166 e helps fill a large gap in historical climate reconstructions although the long term coral 18o based sea surface temperature sst trend is one of warming there are notable decadal fluctuations especially in the early 18th and early 19th centuries mean annual ssts between 1658 and 1900 are estimated to be 0 3 c lower than the 20th century average with interdecadal excursions of 0 5 0 8 c time series analyses of the coral isotope record reveals significant concentrations of variance in the el nino band an inderdecadal spectral peak is present but its robustness requires additional statistical evaluation a secular but irregular decrease in coral 13c values begins in the mid 1800s and may reflect the anthropogenic perturbation of the carbon reservoir these and other results indicate that the new caledonia coral isotope record is a valuable source of information on southwest pacific climate history

high resolution palaeoclimatology of the last millennium a review of current status and future prospects this review of late holocene palaeoclimatology represents the results from a pages clivar intersection panel meeting that took place in june 2006 the review is in three parts the principal high resolution proxy disciplines trees corals ice cores and documentary evidence emphasizing current issues in their use for climate reconstruction the various approaches that have been adopted to combine multiple climate proxy records to provide estimates of past annual to decadal timescale northern hemisphere surface temperatures and other climate variables such as large scale circulation indices and the forcing histories used in climate model simulations of the past millennium we discuss the need to develop a framework through which current and new approaches to interpreting these proxy data may be rigorously assessed using pseudo proxies derived from climate model runs where the answer is known the article concludes with a list of recommendations first more raw proxy data are required from the diverse disciplines and from more locations as well as replication for all proxy sources of the basic raw measurements to improve absolute dating and to better distinguish the proxy climate signal from noise second more effort is required to improve the understanding of what individual proxies respond to supported by more site measurements and process studies these activities should also be mindful of the correlation structure of instrumental data indicating which adjacent proxy records ought to be in agreement and which not third large scale climate reconstructions should be attempted using a wide variety of techniques emphasizing those for which quantified errors can be estimated at specified timescales fourth a greater use of climate model simulations is needed to guide the choice of reconstruction techniques the pseudo proxy concept and possibly help determine where given limited resources future sampling should be concentrated

atmospheric and oceanic evidences of el nino southern oscillation events in the south central pacific ocean from coral stable isotopic records over the last 137 years we measured 18o and 13c in porites lutea collected in the moorea lagoon where the instrumental records show that an el nino southern oscillation enso event implies both a cloud cover decrease and a weak sea surface temperature sst increase two proxies allow an enso record to be reconstructed at moorea the annual 13c anomaly associated with the south pacific convergence zone motion and an annual 18o anomaly showing increased sst the frequency bands exhibited by the singular spectral analysis ssa and the multitaper method of the annual 18o and 13c records are centered on 2 5 and 5 2 years and 2 4 and 3 2 years respectively which are the main enso modes we used ssa to reconstruct enso events at moorea over the past 137 years results indicate that climate variability at this site is strongly affected by enso events

the p velocity within the tonga benioff zone determined from traced rays and observations p waves with travel time residuals between 0 s and 12 s are observed at regional stations in samoa afi and raoul island rao for 39 earthquakes in tonga with focal depths between 70 km and 300 km these anomalously large residuals apparently are produced because seismic phases travel along the strike of the tonga benioff zone within the high velocity subducted lithosphere for up to 1200 km before arriving at afi and rao to eliminate erroneous residuals caused by poor event locations we selected 11 stations and reread the available p times at these stations for the 39 events these arrivals and pp p intervals were used to relocate the events using a variant of the joint hypocenter determination method then the pattern of residuals at afi and rao not used in the relocation was compared to the pattern of residuals expected for various models of the subducted lithosphere as determined by ray tracing the observed pattern of residuals at afi is consistent with the ray traced models if some of the first arrivals are produced by rays traveling directly along the strike of the subducting lithosphere and if others are produced by rays which reflect once off the upper surface of the subducting lithosphere before arriving at afi the observed residuals can be explained by a model where the p velocity in the subducted lithosphere is 8 higher than the velocity in the herrin model the residuals are fit even better by a layered slab model in which the seismic velocity is about 6 higher than the herrin velocity at the upper surface of the subducted lithosphere and about 9 higher at the bottom of the slab these velocity contrasts could be produced if the temperature in the slab was 700 c cooler than the surrounding mantle and if there were no partially melted material within the slab the existence of these anomalously large residuals suggests that the high velocity region in the upper 300 km of the mantle beneath tonga must be fairly continuous over distances of 1000 km and more

climatic constraints on growth rate and geochemistry sr ca and u ca of the coral siderastrea stellata in the southwest equatorial atlantic rocas atoll brazil although relatively rare compared to similar latitudes in the pacific or indian oceans massive coral colonies are present in the tropical equatorial southwestern atlantic ocean however detailed geochemical compositions of these corals are still largely unknown in this work we present growth rates sr ca and u ca ratios of the coral colony siderastrea stellata sampled at rocas atoll off the brazilian coast these variables are primarily affected by sea surface temperature sst at seasonal scale and by wind stress at interannual scale these results represent a broad new finding a lower significance at the interannual time scale between sr ca and u ca with respect to sst is attributed to the low sst amplitude closed to equator an investigation on the dependence of coral growth rates with respect to the cloud shading effect promoted by the intertropical convergence zone itcz does not show significant influence additionally rain seems to act on local geochemistry of sr ca ratios and growth rate at the decadal scale

enhanced multidecadal climate variability in the seventeenth century from coral isotope records in the western indian ocean 1 the slowly growing coral diploastreaheliopora affords a novel opportunity to obtain multicentury records of paleoclimate including details of the interannual rhythms associated with the el nino southern oscillation enso system we examine climate variability in an enso teleconnected region using new oxygen isotope records from d heliopora spanning most of the twentieth 1896 1998 and seventeenth 1622 1722 centuries from the mafia archipelago tanzania the modern record demonstrates coherency with relevant instrumental and proxy time series documents twentieth century warming and displays significant power at enso periodicities the seventeenth century record lacks any trend exhibits interannual variance comparable to the modern record and displays a pronounced interdecadal signal not evident in the twentieth century that correlates with other tropical and hemispheric climate records we find no clear evidence of solar irradiance influence on interannual variability in the western indian ocean during these intervals although the mean sea surface temperature appears to vary inversely with insolation

oceanographic variability in the south pacific convergence zone region over the last 210 years from multi site coral sr ca records 1 in the south pacific convergence zone spcz the variability in a sub seasonally resolved microatoll porites colony sr ca record from tonga and a previously published high resolution record from fiji are strongly influenced by sea surface temperature sst over the calibration period from 1981 to 2004 r2 0 67 0 68 however the sr ca derived sst correlation to instrumental sst decreases back in time the lower frequency secular trend 1 c and decadal scale 2 3 c modes in sr ca derived sst are almost two times larger than that observed in instrumental sst the coral sr ca records suggest that local effects on sst generate larger amplitude variability than gridded sst products indicate reconstructed 18o of seawater 18osw at these sites correlate with instrumental sea surface salinity sss r 0 64 0 67 but not local precipitation r 0 10 to 0 22 demonstrating that the advection and mixing of different salinity water masses may be the predominant control on 18osw in this region the sr ca records indicate sst warming over the last 100 years and appears to be related to the expansion of the western pacific warm pool wpwp including an increasing rate of expansion in the last 20 years the reconstructed 18osw over the last 100 years also shows surface water freshening across the spcz the warming and freshening of the surface ocean in our study area suggests that the spcz has been shifting expanding southeast possibly related to the southward shift and intensification of the south pacific gyre over the last 50 years in response to strengthened westerly winds

validation of coral temperature calibrations geochemical analyses of coral skeletons are increasingly used to estimate past sea surface temperatures ssts in this paper we suggest that the standard method of calibrating geochemical time series against a usually short local time series requires modification in order to draw large scale inferences about climate from coral proxy data it is also necessary to 1 calibrate against larger fields such as the local gridded data sets and 2 validate results against an independent data set e g early 20th century this approach has been applied in a pilot study to a coral record from new caledonia despite a high 18o correlation r 0 88 with the in situ and gridded sst data sets estimated early 20th century temperatures are more than 1 5 c colder than observed if the standard seasonal calibration is used regression against mean annual temperatures which has a different slope relation yields better estimates of early 20th century ssts however testing of a sr ca record from new caledonia yields better agreement with early 20th century ssts routine validation exercises for other coral sites are necessary to clarify the robustness of geochemical coral proxies as estimators of past environmental change

coral oxygen isotope records of interdecadal climate variations in the south pacific convergence zone region 1 the south pacific convergence zone spcz a region of high rainfall is a major feature of subtropical southern hemisphere climate and contributes to and interacts with circulation features across the pacific yet its past temporal variability and forcing remain only partially understood here we compare coral oxygen isotopic 18o series spanning a d 1997 1780 and a d 2001 1776 from two genera of hermatypic corals in fiji located within the spcz to examine the fidelity of these corals in recording climate change and spcz interdecadal dynamics one of these coral records is a new 225 year subannually resolved 18o series from the massive coral diploastreaheliopora diploastrea s use in climate reconstructions is still relatively new but this coral has shown encouragingly similar interannual variability to porites the coral genus most commonly used in pacific paleoclimate studies in fiji we observe that interdecadal 18o variance is also similar in these two coral genera and diploastrea contains a larger amplitude interdecadal signal that more closely tracks instrumental based indices of pacific interdecadal climate change and the spcz than porites both coral 18o series record greater interdecadal variability from 1880 to 1950 which is consistent with the observations of folland et al 2002 who reported higher variability in spcz position before 1945 these observations indicate that diploastrea will likely provide a significant new source of long term climate information from the spcz region

a seismological constraint on the depth of basalt eclogite transition in a subducting oceanic crust the oceanic crust primarily has a basaltic composition1 2 which must transform into eclogite on subduction of the oceanic crust beneath continents3 4 there has been a considerable debate about the role of the basalt eclogite transformation in driving lithospheric plate motion5 and in the thermal regieme of subducting plates6 how important this transformation is in tectonics critically depends on the depth of transformation which is affected by factors such as temperature7 8 bulk rock chemical composition2 water content9 and perhaps stress environment becuase it would be practically impossible to evaluate all these factors correctly we attempt here to constrain the transformation depth by a more direct seismological method

calibration of stable oxygen isotope signatures in galapagos corals a 2 year 1993 1994 study was conducted in the galapagos islands ecuador to determine the relationship between 18o in skeletal carbonate and sea surface temperature sst in three species of reef building corals pavona clavus pavona gigantea and porites lobata coral samples were grown at 3 10 and 3 m depth at bartolome island champion iisland and urvina bay isabela island respectively hourly measurements of sst and sea surface salinity sss were taken at each site immediately adjacent to colonies which were stained biannually to establish the chronology of growth in addition surface waters were sampled periodically bimonthly to monthly at each site to determine variation in 18o seawater results indicate the mean annual ssts were similar between sites varying from 22 9 c at champion to 23 8 c at urvina bay comparisons of monthly sst averages between instrumental and remote sensing satellite 1 1 grid data show a high correspondence r2 ranging from 0 84 to 0 94 indicating that remote sensing data are useful for interpreting the 18o record in corals when instrumental data are lacking here 18ocoral analyses of eight specimens show that coralline aragonite is a reliable indicator of sst in galapagos in general higher resolution coral sampling year resolved more of the monthly variation in sst up to 97 at a sampling resolution of 1 4 samples per millimeter of linear skeletal growth comparisions of the 18ocoral signal among and between species at the same site showed consistent seasonal patterns of variation closely tracking sst in addition comparisons between sites were highly concordant with some differences reflecting local variation in sst seasonal patterns however were essentially the same over the entire region thus we conclude that the 18ocoral signal from coral skeletons in galapagos can be used to interpret regional changes in sst variation

tomographic evidence for the eurasian lithosphere subducting beneath south taiwan 1 a tomographic image of the crust and upper mantle beneath the taiwan island as derived from local regional and teleseismic data simultaneously revealed a high velocity zone from the surface down to a depth of 300 km locating beneath south taiwan to the south of latitude 24 n we interpret this high velocity zone to be the subducted eurasian lithosphere our result is different from a global tomography study that shows the eurasian plate subducting beneath most part of the taiwan island down to 670 km depth this down going model of the eurasian lithosphere implies that the tectonic framework of taiwan has been changing from subduction in the south to collision in the north which provides geophysical evidence supporting the previous proposed models the subducted eurasian lithosphere colliding with the subducted philippine sea plate would have contributed to the mountain building active seismicity and crustal deformation in the study region due to the lower part of the eurasian continental plate subducted beneath south taiwan

existence of a seismic belt in the upper plane of the double seismic zone extending in the along arc direction at depths of 70 100 km beneath ne japan 1 we relocated microearthquakes using data obtained via a dense seismic network and systematically detected the characteristic distribution of the upper seismic plane seismicity within the pacific slab beneath ne japan we found a seismic belt parallel to the iso depth contour of the plate interface that is beneath the forearc area at depths of 70 100 km indicating that the distribution of the upper plane earthquakes is non uniform the location of the deeper limits of this belt and seismicity of the upper seismic plane appear to correspond respectively to two facies boundaries where h2o contents change in the slab crust events in the upper seismic plane have mainly down dip compression type focal mechanisms but several events have normal fault type nf type versions whose spatial distribution appears to correspond to these boundaries these nf events might be induced by the tensional stress field that is caused by volume reduction due to dehydration reactions

origin of the south pacific convergence zone abstract the importance of the presence of south america and australia to the existence and orientation of the south pacific convergence zone spcz during january is explored using the ecmwf t21 model each of the continents is removed from the model and replaced with an ocean surface and the resulting precipitation and circulation associated with the spcz are then compared to a perpetual january control run results show that the presence of south america and the equatorial pacific upwelling zone does not appear to be crucial to the spcz but that the removal of australia destroys the southern monsoon and substantially weakens the western part of the spcz this suggests that the northwest southeast orientation of the spcz during southern summer is more dependent on interactions with the midlatitude westerlies over the south pacific than on the distribution of sea surface temperature and land over the southern hemisphere

high frequency shear wave propagation across the hellenic subduction zone abstract this study investigates shear wave propagation across the hellenic subduction zone using high quality waveforms of 71 intermediate depth events 40 160 km depth the data have been recorded by a permanent seismic network consisting of 22 broadband three component stations that cover most parts of greece shear waves can be efficiently transmitted with low attenuation q s 1100 through the descending slab which extends laterally over much of the forearc area with a northwest southeast strike the slab also appears to be continuous downdip in the depth range 60 160 km even though it was found that a gap smaller than 10 km would not affect shear wave efficiency significantly two highly attenuating areas have been detected one in the central southeast aegean corresponding to the mantle wedge and the other in the northern aegean probably caused by elevated upper mantle temperatures owing to the ongoing extension in that area these results provide additional constraints for the geometry of the hellenic subduction zone and the geodynamic setting of the aegean region

a model for the termination of the ryukyu subduction zone against taiwan a junction of collision subduction separation and subduction boundaries 1 the nw moving philippine sea plate psp collides with the eurasian plate eup in the vicinity of taiwan and at the same time it subducts toward the north along sw ryukyu the ryukyu subduction zone terminates against eastern taiwan while the ryukyu trench is a linear bathymetric low about 100 km east of taiwan closer to taiwan it cannot be clearly identified bathymetrically owing to the deformation related to the collision making the location of the intersection of the ryukyu with taiwan difficult to decipher we propose a model for this complex of boundaries on the basis of seismicity and 3 d velocity structures in this model the intersection is placed at the latitude of about 23 7 n placing the northern part of the coastal range on eup as psp gets deeper along the subduction zone it collides with eup on the taiwan side only where they are in direct contact thus the eurasian plate on the taiwan side is being pushed and compressed by the nw moving philippine sea plate at increasing depth toward the north offshore of northeastern taiwan the wedge shaped eup on top of the ryukyu subducting plate is connected to the eup on the ryukyu side and coupled to the nw moving psp by friction at the plate interface the two sides of the eup above the western end of the subduction zone are not subjected to the same forces and a difference in motions can be expected the deformation of taiwan as revealed by continuous gps measurements geodetic movement along the east coast of taiwan and the formation of the hoping basin can be understood in terms of the proposed model

subduction zone guided waves and the heterogeneity structure of the subducted plate intensity anomalies in northern japan 1 the subducting pacific plate acts an efficient waveguide for high frequency signals and often produces anomalously large intensity on the eastern seaboard of northern japan during deep earthquakes the waveform records in the region of high intensity show a low frequency f 2 hz later arrivals with a long coda this behavior is not explained by a simple subduction zone model comprising a high velocity plate with low attenuation from the analysis of observed broadband waveforms and numerical simulation of seismic wave propagation in the pacific subduction zone we demonstrate that the high frequency guided waves traveling in the subducting plate arise from the scattering of seismic waves by heterogeneity in plate structure our preferred model of the heterogeneity has elongated scatterers parallel to the plate margin described by a von karmann function with a downdip correlation length of about 10 km and much shorter correlation length of about 0 5 km in thickness the standard deviation of wave speed fluctuations from the averaged background model is about 2 this new heterogeneous plate model generates significant scattering of seismic waves with wavelengths shorter than correlation distance in thickness but low frequency waves with long wavelengths can easy tunnel through such lamina structure the result is frequency selective propagation characteristics with a faster low frequency phase followed by large and high frequency signals with very long coda a low wave speed channel effect from the former oceanic crust at the top of the subducting slab is not necessary to explain the observed dispersed signals and the very long high frequency coda three dimensional simulations using the earth simulator supercomputer for modeling of high frequency seismic wave propagation in the pacific subduction zone including plate heterogeneity clearly demonstrate the scattering waveguide effects for high frequency seismic waves traveling in the plate the region of large intensity for the heterogeneous model migrates away from the hypocenter into northern japan with an elongated zone along the pacific coast almost comparable to the observations from deep events in the pacific plate

transition from oblique subduction to collision earthquakes in the southernmost ryukyu arc taiwan region tectonic characteristics of the region between taiwan and the southernmost ryukyu arc are inferred from a detailed analysis of local seismicity and source parameters of 62 recent earthquakes of 5 5 mb 6 6 five major seismogenic structures can be delineated the collision seismic zone csz the interface seismic zone isz the wadati benioff seismic zone wbsz the lateral compression seismic zone lcsz and the okinawa seismic zone osz in the csz located along the east coast of taiwan and offshore earthquake focal mechanisms show horizontal p axes distributed in two directions 287 10 and 333 16 possibly reflecting a strain partition associated with the relative plate convergence between the eurasia plate and the philippine sea plate the corresponding seismic strain tensor indicates a maximum compressive strain rate of 1 2 10 7 yr 1 along 293 and a comparable extension in vertical direction presumably resulted from plate collision in the region the geometry of the isz which is distorted significantly at its westernmost end can be approximated by a north dipping plane that is gradually pushed northward with increasing dip the seismogenic portion of the interface spans a short depth range from 10 km to 35 km a clear pattern of earthquake slip partition is observed the average slip vector residual is as large as 35 seismic strain patterns within the subducted philippine sea slab show predominantly downdip extension between 80 and 120 km and downdip compression at 270 km different from the pattern of strain segmentation observed for the rest of the ryukyu arc where the northern and southern portions are dominated by downdip extension and compression respectively owing to the large convergence obliquity the slab is descending at a rate significantly slower near taiwan than in the southern ryukyu thus we interpret the appearance of downdip extension within the subducted lithosphere as a combined result of oblique subduction and the slab s negative buoyancy a number of thrust or oblique strike slip earthquakes between isz and wbsz show a consistent pattern of lateral compression with p axes oriented roughly parallel to the local strike of the trench arc system they are probably due to the compressive strain originated from the collision and transmitted laterally within the lithosphere shallow normal faulting earthquakes show successive rotation of t axes from approximately n s in the okinawa trough to approximately e w in northeast taiwan possibly as a result of interaction between the extension from the opening of the okinawa trough and the compression from collision one normal event january 18 1991 mb 5 9 occurred in the central range with t axis roughly parallel to the structural trend of taiwan implying that the nature of the orogeny in taiwan has changed from thin skinned deformation to lithospheric collision involving the whole crust and uppermost mantle

sr ca sea surface temperature calibration in the coral porites lutea from subtropical northern south china sea strontium to calcium sr ca ratios in annual bands of porites corals are commonly used as past sea surface temperature proxy in tropical oceans whereas studies that refer to sr ca sst calibration in high latitude corals are rather rare in general here we present a 50 year 1961 2010 near fortnightly sr ca record in two porites lutea corals living near the northern limit of reef building corals in the subtropical northern south china sea where winter temperatures are extreme for hermatypic corals the sr ca time series shows a clear annual cyclicity with marked sharp narrow winter peaks comparison with an instrumental sst record since 1961 indicates that this sr ca record is chiefly modulated by sst two different methods are discussed for calibrating sr ca with sst the correlation between interpolated sr ca and sst is significant but the coefficient is relatively low mainly attributed to extreme cold winter ssts similar to 16 degrees c which cause a significant decrease or even cessation of coral skeletal extension another modified method using only annual low sr ca values which could clearly be matched with the same features in the instrumental sst record is more reliable the modified regression equation does not encompass ssts below 24 degrees c the fidelity of the coral based sr ca sst calibration was assessed and the precision of the method is estimated to be 031 0 62 degrees c based on the calibration verification exercise the modified method is suggested in marginal coral areas with extreme intra annual sst variation e g from 13 to 30 degrees c c 2013 elsevier b v all rights reserved

reconstruction of the east china sea palaeoenvironment at 16 ka by comparison of fossil and modern faviidae corals from the ryukyus southwestern japan we conducted paired measurements of the sr ca ratio and oxygen and carbon stable isotopes of a fossil faviidae coral specimen myk90 age 16 ka collected from near miyako island the ryukyus southwestern japan our study aimed to reconstruct the palaeoenvironment in the east china sea at 16 ka by comparing the fossil sample with modern faviidae corals our data with annual or longer time resolution may be very suitable for palaeoceanographic reconstruction although no general calibration method for faviidae corals has been reported our calibration showed that the annual mean sea surface temperature was approximately 5 c lower and sea surface salinity sss at the study site was locally higher at 16 ka than at present even though the mouths of the yellow and changjiang rivers were east of their present locations because sea level was much lower our results suggest that the influence of the terrestrial water discharge may not have extended to miyako island weak summer monsoon activity during the last glacial which decreased summer precipitation over the asian continent and an enhanced winter monsoon which may have led to more evaporation likely contributed to the inferred high sss at the study site copyright 2009 john wiley sons ltd

the south pacific convergence zone spcz a review abstract the circulation features associated with the south pacific convergence zone spcz and its accompanying cloud band are reviewed and discussed the paper focuses on the following topics location structure and characteristics of the spcz theories and observations concerning its existence the significance and scope of the spcz in global scale circulation patterns quasi periodic changes in its location and strength and synoptic scale features within its regional influence e g cyclones subtropical jets it concludes with some challenging problems for the future

seasonal growth bands in famennian rugose coral scruttonia kunthi and their environmental significance abstract large colonies of rugose coral scruttonia kunthi occurring in the upper famennian of sudetes southern poland reveal distinct growth banding in their skeletons they were investigated for internal structural characteristics and stable isotopic composition the skeletal tissue consists of alternating light and dark bands which differ in thickness density and morphology of structural elements and in occurrence of corallite contraction and rejuvenescense darker parts with densely arranged thick skeletal elements are thin in comparison to lighter parts in addition they include frequently offsets and contraction of corallites a couplet of dense and less dense bands is interpreted to represent most probably an annual cycle the calculated growth rate for scruttonia kunthi varied from 6 mm yr to 12 mm yr growth band formation was influenced environmentally oxygen isotopic data provide an evidence that high density bands were formed in the season of higher environmental stress with relatively warmer temperatures and higher sedimentation rates carbon isotopic signatures are very uniform and thus enigmatic they indicate that at least growth rate of the skeleton and seawater temperature had no influence on the coral 13 c