a successive steady state model for simulating freshwater discharges and saltwater wedge profiles at baffin bay texas submarine groundwater discharges sgd are an important source of freshwater to coastal bays and estuaries in arid and semi arid regions understanding groundwater flows to these ecologically sensitive bodies is important for coastal environmental sustainability a management oriented mathematical model capable of simulating the flow of groundwater into a coastal bay i e submarine groundwater discharge is developed here using the principles of quasi steady state flow and the existence of a sharp interface between the freshwater and the saltwater portions of the aquifer the model is applied to the baffin bay in south texas a hypersaline coastal body with no major river discharges two global sensitivity approaches the one at a time design oat and the grid based monte carlo sensitivity index are used to identify critical model inputs the sensitivity of the model inputs to the nash sutcliffe efficiency nse criterion is calculated making use of synoptic observed sgd measurements made over a period of one tidal cycle the results of the study indicate that global sensitivity analysis methods are particularly sensitive to the number of model realizations the ability of these techniques to screen out insensitive model inputs increased with increasing number of realizations the variability in the identified inputs was more prominent with the oat sensitivity methods than monte carlo based techniques in general the aquifer properties hydraulic conductivity and aquifer thickness as well as fluid properties seawater and fresh water densities along with the antecedent sgd was noted to be the most sensitive parameters this result indicates that the implementation of sharp front coastal aquifer models can be improved through better hydrogeologic characterization and measuring temperature and salinity data to improve density estimation the global sensitivity methods also help identify reasonable values for model inputs which can serve as a starting point for advanced calibrations the results however indicated that the model is likely over parameterized with different input sets yielding similar nse estimates based on these initial parameter estimates the model was able to capture the general trend in the observed sgd but could not capture the dynamic associated with high water levels in the bay pre calibration global sensitivity analysis is recommended in similar applications as it not only provides insights into future data collection efforts but can also help assess the likely success of model calibration however given the variability among the techniques it is suggested that multiple global sensitivity methods be utilized

numerical modeling of tidal effects on groundwater dynamics in a multi layered estuary aquifer system using equivalent tidal loading boundary condition case study in zhanjiang china this paper presents a numerical modeling study of tidal effects on groundwater dynamics of a multi layered estuary aquifer system in this study to generalize the tidal loading effects on the confined aquifer we used equivalent tidal loading boundary condition based on existing analytical solutions for the confined aquifer in a three dimensional numerical model and then good simulated result was obtained using the numerical model the tide induced groundwater level and confined groundwater discharge dynamics were discussed and the following conclusions were obtained the combined action of sea tide and river tide can enhance the tidal response of groundwater level in the aquifer system especially for the confined groundwater the river tidal effect is more significant in the areas away from coastline although the confined aquifer is separated by a layer of clay from the ocean because of the tidal loading effects the confined groundwater discharge also changes periodically displaying a negative correlation with the tide level fluctuations like the unconfined groundwater discharge using linear functions that express the relationship between the mean confined groundwater flux and sea tide level the confined groundwater flux through the tidal loading boundaries can be approximately estimated when the sea tide level is higher than 4 4 m there would be a risk of seawater intrusion into the confined aquifer in the study area this case study is useful for numerical studying of tidal effects on groundwater resource dynamics in a coastal multi layered estuary aquifer system

aminostratigraphy and faunal correlations of late quaternary marine terraces pacific coast usa recent studies using the extent of racemization of amino acids to date fossil mollusc shells in the arctic1 the british isles2 and on the atlantic3 4 and pacific5 13 coasts of north america have relied mainly on theoretical kinetic models of racemization ages generated in this fashion are highly model dependent and require estimates of integrated long term diagenetic temperatures we present here an alternative empirical approach to aminostratigraphy in which we plot amino acid enantiomeric ratios versus latitude for localities along the pacific coast of the united states and generate isochronal correlations by connecting data points of geographically proximal localities that have similar d l ratios and zoogeographic aspect isochrons are calibrated at a few localities by independent radiometric dates the diagenetic temperature effect on racemization is reflected in the slope of the isochrons but the need to quantify temperature is eliminated

evolution and distribution of the conodonts sweetognathus and iranognathus and related genera during the permian and their implications for climate change abstract the conodont genus sweetognathus which is characterized by pustulose ornamentation on a wide flat topped carina originated in the earliest permian as s expansus from diplognathodus edentulus the asselian through artinskian part of the sweetognathus lineage is well represented in kansas by the successive evolution of s expansus s merrilli s aff s merrilli s whitei and s bucaramangus sweetognathus and iranognathus lineages were mainly confined to tropical areas from the kungurian onward the kungurian and guadalupian part of the sweetognathus lineage is well represented in south china by the successive evolution of s whitei artinskian s guizhouensis lower kungurian s subsymmetricus upper kungurian s iranicus hanzhongensis roadian and s fengshanensis capitanian an additional lineage in west texas is represented by the evolution of s sulcatus to s aff adjunctus to s adjunctus and to s bicarinum in the urals and northwestern pangea the late part of the sweetognathus lineage is represented by rare specimens of s bogoslovskajae upper artinskian lower kungurian during the late artinskian s whitei radiated into s toriyamai and s bucaramangus and also gave rise to neostreptognathodus pequopensis and probably pseudosweetognathus costatus neostreptognathodus exsculptus may have evolved from adetognathus paralautus through adetognathus telfordi sp nov iranognathus characterized by a narrow carina with poorly developed denticles and bearing subtle and smaller pustulose micro ornament replaced sweetognathus at or near the guadalupian lopingian boundary it probably also evolved from diplognathodus in the topmost guadalupian a lineage of iranognathus sp nov a to i erwini can be recognized for the guadalupian and lopingian boundary interval a lineage of iranognathus sp nov a to i movschovithschi to i sosioensis to i tarazi is found throughout the guadalupian and lopingian boundary interval and the wuchiapingian of south china sweetognathus and iranognathus tend to develop homeomorphic accessory nodes iteratively during lowstand periods of global sea level near the artinskian kungurian and guadalupian lopingian boundaries and in the late wuchiapingian sweetognathus and iranognathus seem to be equatorial warm water inhabitants distribution patterns reflect glaciation in gondwana during the asselian and sakmarian a warm climate during the artinskian cooling in north pangea during the kungurian and later permian slight amelioration during the guadalupian warming during the wuchiapingian and cooling during the changhsingian in the peri gondwana region definitions for most of the important sweetognathus species are refined three new species and subspecies iranognathus sp nov a adetognathus telfordi sp nov gullodus duani sp nov are described

reconciling regional continuity with local variability in structure uplift and exhumation of the timor orogen abstract along strike variations in orogenic development can be difficult to constrain resulting assumptions projecting similarity or variability along strike can lead to erroneous conclusions at the orogen scale young orogens provide opportunities to document limits of along strike projection and test factors that may control lateral variability here we present new constraints on the history of uplift exhumation and shortening in the timor orogen from west timor indonesia structural mapping documents a foreland thrust stack of jurassic miocene australian margin strata and a hinterland antiformal stack of permo triassic australian continental units duplexed below banda arc lithosphere biostratigraphy within the piggyback central basin reveals earliest deepwater synorogenic deposition at 5 57 5 53 ma uplift from lower to middle bathyal depths at 3 35 2 58 ma and uplift from middle to upper bathyal depths at 2 58 1 30 ma hinterland permo triassic strata yield apatite u th he ages of 0 33 2 76 ma apatite fission track ages of 2 19 3 53 ma and partially reset zircon u th he ages these thermochronology ages are youngest or most strongly reset in the center of the antiformal stack and yield modeled exhumation rates of 0 45 3 31 km myr a balanced cross section reveals a minimum of 300 km of shortening including 210 km of australian continental subduction below the banda forearc when compared to published results from timor leste these data show that the timing of initial collision synorogenic basin uplift and total shortening amount were broadly similar across the island therefore despite along strike changes in orogen morphology and significant small scale spatial variability in deformation first order structural similarity dominates at large scales we suggest that along strike variations in orogen morphology are due to changes in the distribution of deformation within the orogen driven by differences in backstop strength internal wedge strength and basal decollement friction as well as the presence of the wedge top central basin in west timor

stratigraphic versus environmental significance of permian serrated conodonts around the cisuralian guadalupian boundary new evidence from oman abstract conodonts from the cephalopod limestones of rustaq and ba ad oman have for many years been dated as wordian because of the presence of the ammonoid waagenoceras revised definitions for guadalupian stages and major differences of conodont morphology among apparently coeval faunas necessitate a review of this age assignment the lack of serration within the oman conodont faunas as well as from waagenoceras bearing limestone blocks in sicily differs markedly from conodonts in the guadalupian stratotype sections of west texas these differences have previously been interpreted to be the result of upwelling cold bottom water that may have restricted the distribution of serrated warm water jinogondolella species however our samples from oman are dominated by species with a carinal configuration that is comparable to gondolellids from the equatorial warm water province ewwp abundant species include mesogondolella siciliensis in the lower ammonoid beds and mesogondolella idahoensis lamberti in the upper ammonoid beds if cold bottom water currents were present at oman then these taxa must have been pelagic living in warm surficial water in contrast the north cool water province ncwp includes coeval conodonts that have a different carinal configuration and are dominated by long ranging mesogondolella idahoensis idahoensis these taxa and their morphologic variations represent a geographic cline between the ewwp and ncwp in addition early roadian serrated gondolellids have been recognized in temperate cool water settings in the jilin province ne china the phosphoria basin idaho usa and the sverdrup basin arctic canada these serrated forms extend above the lower roadian in only the phosphoria basin indicating a distribution into temperatures cooler than previously thought at least during the early guadalupian other conodonts from the deep water cephalopod limestones of oman include rare shallow warm water sweetognathids suggesting that these too must have been pelagic if true then cold bottom waters probably played little role in conodont distribution the identified conodont taxa at oman best correlate with the uppermost kungurian at the luodian section of south china and in the guadalupe mountains of west texas suggesting that the lack of serration is not a result of cold water but rather of a stratigraphic position prior to the evolution and expansion of serrated gondolellids in the roadian it is possible that other paleoecologic controls affected distribution and an alternative age assignment of early roadian is considered for these conodonts the ammonoids including advanced species of waagenoceras suggest that the best correlation is with the third limestone of the word formation willis ranch member which correlates with the upper roadian according to ratified global stage definitions there is still an apparent discrepancy between conodont and ammonoid ages but discounting previous wordian ages has considerably reduced this associated fusulinaceans cannot resolve this argument because of profound provincialism but they can contribute to correlation of the global stages with tethyan stages it is here suggested that the kungurian correlates with the upper bolorian to upper murgabian and that the roadian correlates with the lower midian or upper murgabian and lower midian

thermal history of australian passive margin cover sequences accreted to timor during late neogene arc continent collision indonesia abstract paleotemperature indicators and apatite fission track analysis of australian continental margin cover sequences accreted to the active banda arc continent collision indicate little to no heating during rapid late neogene uplift and exhumation thermal maturation patterns of vitrinite reflectance conodont alteration and illite crystallinity show that peak paleotemperatures ppt increase with stratigraphic and structural burial the highest ppt is found in the northern hinterland of the accretionary wedge which was beneath progressively thicker parts of the upper plate towards the north major discontinuities in the pattern of ppt are associated with the position of major thrust ramps such as those forming the ramelau kekneno arch rka ppt for upper triassic to neogene strata south of the rka are 60 80 c which are similar to and in many cases lower than correlative and age equivalent units drilled on the nw australian shelf permian to lower triassic sedimentary strata thrust over younger units within and north of the rka have ppt of 100 220 c thrust sheets accreted beneath the upper plate have ppt approximately 90 c higher than those frontally accreted metamorphism of the northernmost units of these sequences yield ppt of 300 c thrust stacking yields an inverted thermal profile of ppt decreasing discontinuously downward and to the south towards the foreland the timing of ppt is constrained by apatite fission track ages from mostly triassic continental margin cover sequences ages of upper triassic units are primarily coeval with deposition and show little evidence of thermal annealing whereas those of lower triassic units are almost completely annealed and range from 1 8 0 5 19 2 9 7 ma the clustering of apatite fission track ages into two distinct groups indicates that the upper boundary of the partial annealing zone has remained for some time at a triassic stratigraphic interval in the slope and rise of the nw australian continental margin the position of this zone on the present shelf is higher in the stratigraphic column due to the greater thickness of post breakup shelf facies units thrust stacking of rise slope and shelf units produces an inverted vertical profile of increasing apatite fission track age with depth lack of any long confined track lengths in apatite from all of the units requires rapid and recent exhumation of the thrust stack which is coincident with rapid phases of pliocene pleistocene exhumation documented throughout timor these data preclude pre late miocene tectonic burial or pre pliocene exhumation of the nw australian continental margin

early permian ammonoids from the kaeng krachan group of the phatthalung hat yai area southern peninsular thailand an early permian small ammonoid fauna consisting of neocrimites sp agathiceras suessi gemmellaro a girtyi bose agathiceras sp and miklukhoceras sp was found in nodules of a fine sandstone bed exposed in the phatthalung hat yai area of southern peninsular thailand the ammonoid bearing bed belongs stratigraphically to the uppermost part of the kaeng krachan group which is essentially a clastic dominant late carboniferous to early permian stratigraphic unit widely distributed in western and peninsular thailand this ammonoid fauna is considered to be of bolorian kungurian age and includes agathiceras girtyi bose which is described for the first time from thailand the present discovery of bolorian ammonoids suggests that the uppermost part of the kaeng krachan group is slightly younger than previously considered and around the latest early permian this further implies that the continental margin environment of the sibumasu block drastically changed at around bolorian time from a cool clastic dominant shelf condition to a temperate to subtropical carbonate platform due to rapid northward drift after middle artinskian rifting

quaternary sea level events on northern san clemente island california abstract global sea level changes are expressed in the coastal landforms and deposits of northern san clemente island stratigraphic radiometric amino acid and pedologic dating techniques have allowed the development of a chronology of sea level changes for about the last 500 000 yr a uranium series date on coral of about 127 000 yr for the 2nd terrace serves as a calibration point for amino acid age estimates of four other mapped terraces two of these terraces have age estimates of about 80 000 105 000 yr another has an age estimate of about 127 000 yr and the 5th terrace on the west side of the island is estimated to be about 415 000 575 000 yr old these dates correlate reasonably well with marine terraces dated elsewhere and with stages of the oxygen isotope record that are thought to represent high stands of the sea weakly cemented calcareous dune sands eolianites are moderately extensive on northern san clemente island and appear to represent low stands of the sea since calcareous shelf sands were the most likely source a radiocarbon date of about 22 000 yr suggests that the youngest eolianite was deposited during the last glacial maximum an older eolianite is estimated to be about 140 000 195 000 yr old based on stratigraphic relations and degree of soil development the suggested ages for the eolianites also correlate well with oxygen isotope estimates of low sea levels

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

uranium series age of the eel point terrace san clemente island california uranium series analysis of the coral allopora californica verrill from the 2nd 32 m eel point terrace on san clemente island california has yielded an age of 127 000 7 000 yr the eel point terrace is thus correlative with numerous terrace localities on the southern california mainland with coral reefs on barbados and new guinea dated about 120 000 yr and with substage 5e of the marine oxygen isotope record a tectonic uplift rate of about 0 20 m 1 000 yr has been calculated assuming a sea level slightly higher than the present one at the time of terrace formation extrapolation of this uplift rate allows age estimates to be made for other terraces on the island

collisional melange development geologic associations of active melange forming processes with exhumed melange facies in the western banda orogen indonesia analysis of block assemblages matrix clay mineral composition and microfauna and offshore seismic reflection profiles reveal that the bobonaro melange in the timor region is sourced from mud rich australian continental margin sequences that are remobilized during accretion and form various facies depending on the structural conditions of emplacement melange facies include broken formation matrix rich mud injections and classic mixed block in clay facies each of these are distinguished by varying degrees of remobilization mixing and dispersion at different structural positions across the orogenic wedge the most important structural control is whether melange was generated beneath or in front of upper plate banda forearc basement banda terrane at the present collisional deformation front in the timor trough seismic reflection profiles show that melange forms mostly by stratal detachment and fluid assisted remobilization above a basal decollement propagating laterally along overpressured jurassic to cretaceous clay rich sequences of the distal australian continental margin the broken clay rich material injects upward through faults to form intrusive bodies at the base of slope cover sediment to form mud ridges at the surface similar patterns of stratal disruption are exposed onshore in the pliocene kolbano fold and thrust wedge of southern timor which is structurally contiguous with the timor trough deformation front melange in the kolbano mountains is mostly broken formation and matrix rich injections of mud from jurassic and cretaceous units deformation mechanisms include intense layer parallel extension associated with emplacement by mud diapirs that rise from near the decollement upward to the surface along fault conduits in the hinterland of the orogenic wedge east timor and northern west timor melange is dominantly of mixed block in clay facies with large blocks derived from roof thrust sheets of intermixed banda terrane and maubisse formation units at the structural base of these thrust sheets is the sonnebait disruption zone sdz which formed the initial suture between the banda terrane and structurally underthrust australian continental margin sequences during the late miocene to early pliocene the thickest accumulations of mixed block in clay melange in the timor region are found at the southern edge outlet of the sdz near the central and viqueque synorogenic basins the extent of block dispersion and mixing in the sdz is indicative of intense shear strains perhaps induced by an oversupply of accretable material when the suture zone was clogged by underthrusting of the australian continental margin

deformation and metamorphism of the aileu formation north coast east timor and its tectonic significance abstract the large block of metamorphic rocks along the north coast of east timor is of special interest as it occurs at the boundary between continental and oceanic crust in an island arc continent collision zone a detailed study of the structure and metamorphic history of 400 km2 of this formation showed it has a complex history of penetrative deformation but the structure is coherent pelites psammites and limestones interlayered with dolerites and amphibolites have been metamorphosed in a medium pressure environment they now form a metamorphic province zoned from low greenschist facies in the southwest to upper amphibolite facies in the east the earliest recognised deformation phase predated the metamorphism and produced a widespread layer parallel schistosity but no recognisable folds the second deformation phase post dated the metamorphic maximum and micropetrological evidence indicates a gradual cooling during this event this deformation produced tight folds with an axial plane schistosity and transposed the earlier structures the progressively weaker third and fourth phases developed crenulation cleavages and related folds under greenschist facies conditions open fifth phase macroscopic folds were probably synchronous with strike slip faulting parallel to the north coast later dip slip faulting juxtaposed the aileu formation with permian and mesozoic sediments of very low metamorphic grade reconnaissance k ar radiometric dating using hornblende and biotite showed the prograde metamorphic maximum occurred before 11 ma ago and implies that the second and strongest deformation phase occurred in the late miocene this young age establishes the relationship of the deformation events to the collision between australia and the inner banda arc the proposed models for the structure of timor must be modified to fit the deformation history of the aileu formation if timor is essentially autochthonous the aileu formation was probably deposited in a palaeozoic graben and the metamorphic maximum may have occurred in the jurassic the overthrusting models must be modified in the light of the close correlation in time between penetrative deformation and emplacement of the proposed thrust sheets the analogy proposed between timor and normal convergent margins is not supported but it may be possible to draw analogies with the molucca sea

distribution and characteristics of mixed transitional mid permian late artinskian ufimian marine faunas in asia and their palaeogeographical implications abstract the permian marine biogeography of the asian region is characterised by the development of three broad realms boreal tethyan and gondwanan in the early early permian asselian to early artinskian there seems to have existed sharp biogeographical boundaries with no transitional zones between the realms presumably due to the effect of gondwanan glaciation and sharp climatic zonation the mid permian late artinskian to ufimian of the asian region is distinguished by the rise of two broad transitional zones in which mixed marine faunas flourished the northern transitional zone north and northeast china sikhote alin central and northeast japan is characterised by an admixture of both warm water cathaysian and cold temperate boreal genera the southern transitional zone arabian peninsula iran afghanistan the karakorum southeast and central pamir salt range central and northwest tibet shan thai terrane timor and western irian jaya on the other hand is distinguished by incorporating faunal elements of both gondwanan and cathaysian origin the mixed faunas of both transitional zones share several antitropically distributed genera e g monodiexodina lytvolasma and spiriferella and are succeeded by palaeotropical tethyan faunas of late permian age it has been postulated that the mixed mid permian fauna of the northern transitional zone was probably formed in an epicontinental sea which was connected to both the asian tethys and the arctic which facilitated the migration of cathaysian and boreal forms into the epicontinental sea and subsequent faunal mixing the formation of the mixed faunas of the southern transitional zone on the other hand is probably related to the breaking off of the cimmerian blocks from northern gondwana and subsequent drifting into a lower latitudinal zone with geographical proximity to both gondwana and cathaysia during the mid permian

updated gondwana permian cretaceous earth history of australia abstract permo carboniferous glaciation confined to icecaps and mountain glaciers was followed by permian coal measures and early triassic barren measures and redbeds in the east terminally deformed in the mid triassic coal deposition resumed during the late triassic and tholeiite was erupted in the southeast after rifting the western margin was formed by the opening of the indian ocean at 156 and 132 ma at 140 ma a brief glaciation affected central australia by the 99 ma mid cretaceous the southern margin was finally shaped by the opening of the southeastern indian ocean the shoreline retreated to the present coast from the maximum aptian shoreline of an epeiric sea and the eastern highlands were uplifted to produce the present morphology of australia new data relate to the permo carboniferous and early cretaceous glaciations the kiaman reversed paleomagnetic interval events about the permian triassic boundary including possible impact craters advances in palynology invertebrate paleontology macrofloral paleontology and paleobiogeography the provenance of sediments by u pb ages and host rock affinity of zircons stable isotopes and biomarkers in petroleum systems coal environments calibrating the time scale with u pb ages of zircons fission track thermotectonic imaging geothermal energy and terranes split off the western margin

optimal annual operation of a coastal aquifer optimal annual operation of a coastal aquifer is determined by using a multiple objective linear programing model based on a multicell model of the aquifer and a network representation of the hydraulic distribution system the decision variables are pumping and or recharge quantities in each cell four objective functions are based on 1 a desired ground water surface map 2 a desired location of the sea water fresh water interface toe in each coastal cell 3 a desired concentration map of a selected conservative contaminant and 4 minimization of the energy for pumping and recharge an approximate linearized expression of the location of the interface has been developed to enable the use of linear programing as the optimization method a trade off procedure is employed for identifying the most desirable solution the model is applied to a segment of the coastal aquifer in israel a 44 km strip along the coast with a width of 7 to 15 km and results are discussed

management of coastal aquifers based on nonlinear optimization and evolutionary algorithms abstract a method of assessing the optimum pumping rates of coastal aquifers based on nonlinear optimization and evolutionary algorithms ea is developed the objective is to maximize the total pumping rate while protecting the wells from sea water intrusion the formulation of the constraints is based on numerical simulation of the freshwater flow equations the simulation model is based on the sharp interface and the ghyben herzberg approximation and is applicable to unconfined aquifers and steady state flow the single potential formulation of water resour res 12 1976 1165 is followed and the governing equations are solved numerically using finite differences the numerical model can handle aquifers of complex shapes nonuniform hydraulic conductivity nonuniform distribution of surface recharge etc the constraints are nonlinear with respect to the decision variables resulting in a nonlinear optimization problem two optimization methods are investigated specifically sequential quadratic programming sqp and evolutionary algorithms ea sqp requires less computer time than ea but can get stuck on local optimum solutions the simulation and optimization methodology is applied to a real unconfined coastal aquifer in the greek island of kalymnos for determining the optimal pumping rates while protecting the wells from sea water intrusion

the structural evolution of the timor collision complex eastern indonesia abstract the structural style of timor is consistent with foreland fold belt processes and zones of frontal accretion and underplating can be recognized in the australian parautochthonous sequence the parautochthon is overlain by an allochthonous sequence which corresponds to the pre collisional oceanic forearc in northern timor the parautochthon has been underplated directly beneath the allochthonous basement unlike previous interpretations of timor in terms of foreland fold belt processes the timor foldbelt is here interpreted as having evolved in a fairly straightforward way from the pre collisional forearc by the sequential addition of thrust slices of australian continental crust to the front and base of the developing collision complex

patterns and paleoenvironmental implications of end permian extinction of rugosa in south china abstract late permian rugose corals are undoubtedly the last phylogenetic representatives of the rugosa these corals are widely though sporadically distributed notably in south china the late permian corals of south china decrease markedly in diversity and are represented by surviving genera from the maokouan showing common patterns of disappearance morphologically and phylogenetically colonial wentzelellinae mostly disappeared by the end of the maokouan followed by solitary wentzelellinae and later waagenophyllinae having simple morphologies non dissepimented solitary corals and fasciculate waagenophyllinae though morphologically simple are common during the late permian ranging up to the latest permian permian rugosa apparently show two terminal patterns suggesting environmental differences one pattern is terminated with a progressive reduction leaving only non dissepimented solitary corals as survivors and the other pattern is distinguished by the disappearance of the platform dwelling colonial corals at the end of the permian the general trend characterized by later disappearance of the simpler corals reflects progressively adverse changes in the marine environment the persistence and disappearance of a latest permian waagenophyllum fauna suggests that the regional continuation of favorable environments followed by the onset of and abrupt severe though temporary environmentalchanges for coral growth the causes of rugosan extinction are not necessarily attributed to factors characteristics of the latest permian time and the extinction was individually stepwise each different event disappearance correlating with and possiblycaused by variable factors such as sea level fluctuations and volcanic activity multiple interactions of individual factors on a local and global scale affected each faunal component resulting in selection of corals that culminates in the regional and finally global disappearance of rugosa

an evaluation of uranium series dating of fossil echinoids from southern california pleistocene marine terraces abstract fossil sea urchins strongylocentrotus from pleistocene marine terraces on the southern california channel islands have been dated by the uranium series method in order to test the suitability of echinoids for dating marine terraces results indicate that urchin plates and spines do not behave as closed systems with respect to both uranium and thorium calculated ages based on these data do not agree with uranium series ages 120 000 and 127 000 yrs obtained previously from corals from the same localities thus fossil sea urchins strongylocentrotus are not considered suitable for uraniumseries dating of pleistocene marine terrace deposits

amino acid age estimates of marine terraces and sea levels on san nicolas island california fourteen marine terraces rising to an elevation of 274 m have been mapped on san nicolas island california the lowest terrace is 105 000 yr old on the basis of amino acid ratios in fossil mollusks slightly lower than those from the 120 000 yr old uranium series dated second terrace the age estimate and present elevation of the lowest terrace along with an assumption of constant uplift rate indicate a paleo sea level estimate of 10 to 12 m at about 105 000 b p supporting the general barbados model of sea level history the fourth and fifth terraces probably represent separate high sea level stands during the same interglacial complex 400 000 b p the eight and tenth terraces have amino acid ratios near equilibrium and imply ages of 600 000 yr collectively the data suggest long term average quaternary uplift rates of 0 2 0 3 m 1000 yr

comments on some permian conodont faunas reported from southeast asia and adjacent areas and their global correlation abstract some important conodont faunas reported from southeast asia excluding south china and japan are re evaluated on the basis of the improved taxonomy and resulting newly established provincialism these faunas are representative of either the equatorial warm water province ewwp or the peri gondwana cool water province gcwp except that the fauna from jilin north china represents the north cool water province ncwp the gcwp is marked by vjalovognathus and or merrillina in the cisuralian vjalovognathus merrillina and mesogondolella in the guadalupian and vjalovognathus and mesogondolella sheni or merrillina in the lopingian the ewwp is characterized by the absence of gondolelloides and vjalovognathus in the early and middle cisuralian abundance of sweetognathus and pseudosweetognathus in the kungurian late cisuralian dominance of jinogondolella and sweetognathus in the guadalupian and dominance of clarkina and iranognathus in the lopingian mixed faunas are recognized in regions on the border between the ewwp and gcwp including western timor during the artinskian southeast pamirs during the kungurian and the salt range during the guadalupian and lopingian

age estimates and uplift rates for late pleistocene marine terraces southern oregon portion of the cascadia forearc marine terraces are prominent landforms along the southern oregon coast which forms part of the forearc region of the cascadia subduction zone interest in the cascadia subduction zone has increased because recent investigations have suggested that slip along plates at certain types of convergent margins is characteristically accompanied by large earthquakes in addition other investigations have suggested that convergent margins can be broadly classified by the magnitude of their uplift rates with these hypotheses in mind we generated new uranium series amino acid and stable isotope data for southern oregon marine terrace fossils these data along with terrace elevations and two alternative estimates of sea level at the time of terrace formation allow us to determine terrace ages and uplift rates uranium series analysis of fossil coral yields an age of 83 5 ka for the whisky run terrace at coquille point in bandon oregon a combination of amino acid and oxygen isotope data suggest ages of about 80 and 105 ka for the lowest two terraces at cape blanco these ages indicate uplift rates of 0 45 1 05 and 0 81 1 49 m kyr for coquille point and cape blanco respectively late quaternary uplift rates of marine terraces yield information about deformation in the overriding plate but it is unclear if such data vary systematically with convergent margin type in order to assess the utility of the southern oregon uplift rates for predicting the behavior of the cascadia subduction zone we compared late quaternary uplift rates derived from terrace data from subduction zones around the world on the basis of this comparison the southern oregon rates of vertical deformation are not unusually high or low furthermore late quaternary uplift rates show little relationship to the type of convergent margin these observations suggest that local structures may play a large role in uplift rate variability in addition while the type of convergent margin may place an upper limit on possible uplift rate greater upper limits serve to increase the range of possible uplift rates in the case of the southern oregon coast variability in uplift rate probably reflects local structures in the overriding plate and the rate of uplift cannot be used as a simple index of the potential for great earthquakes along the southern cascadia subduction zone

permo triassic evolution of gondwanan eastern indonesia and the final mesozoic separation of se asia from australia abstract continental fragments with australian gondwanan stratigraphic affinities are widely distributed throughout the eastern indonesia collision complex despite their structural isolation from one another as a consequence of tertiary orogenesis these fragments show a remarkably uniform pattern of permo triassic tectonostratigraphy ranging from a granitoid belt in the north through a continental platform to an intracontinental rift system in the south within the rift system complementary upper and lower plate rifted margins can be recognised in the northern and southern banda arcs respectively the northern granitoid belt was initiated in the mid carboniferous whilst the intracontinental rift system began to develop in latest carboniferous earliest permian times extension in the northern rift margin ceased in the mid carnian early late triassic contemporaneous with a marked decline in igneous activity in the granitoid belt to the north the sibumasu terrane of mainland se asia probably originated on the gondwanaland continental margin adjacent to reconstructed eastern indonesia but rifted away during the early permian previous interpretations have seen this rifting as marking the final separation between gondwanaland and continental terranes now forming se asia alternatively it is suggested here that gondwanan eastern indonesia acted as an indirect continental connection between sibumasu indochina and australia during the permian and triassic this continental isthmus permitted continuing limited floral and faunal interchange between gondwanaland and se asia until a final separation in the late triassic the mid carnian structural event in eastern indonesia is interpreted as related to this separation

evolution of permian conodont provincialism and its significance in global correlation and paleoclimate implication the main components of asselian through artinskian conodont faunas found around the world are basically the same and the provincialism is indicated only by less common endemic elements such as gondolelloides and new genus a henderson in north pangea sweetognathus bucaramangus around the equator and vjalovognathus in eastern gondwana provincialism is marked by differences at the species level of mesogondolella neostreptognathodus and sweetognathus during the kungurian and becomes very distinct with differences at the genus level during the guadalupian and lopingian three provinces of permian conodonts referred to as the north cool water province ncwp the equatorial warm water province ewwp and the peri gondwana cool water province gcwp are recognized the ncwp is marked by gondolelloides in the early cisuralian dominance of neostreptognathodus and no or rare sweetognathus in the late cisuralian dominance of merrillina and mesogondolella and absence of sweetognathus in the guadalupian and dominance of merrillina and mesogondolella and absence of iranognathus in the lopingian the ewwp is characterized by the absence of gondolelloides and vjalovognathus in the cisuralian abundance of sweetognathus and pseudosweetognathus in the kungurian late cisuralian jinogondolella and sweetognathus in the guadalupian and clarkina and iranognathus in the lopingian the gcwp is marked by vjalovognathus merrillina in the cisuralian vjalovognathus merrillina and mesogondolella in the guadalupian and vjalovognathus and merrillina in the lopingian mixed faunas are recognized in regions bordering between the ewwp and gcwp including western timor during the artinskian pamirs during the kungurian and the salt range during the guadalupian and lopingian three different conodont zonations are proposed one for each of the three conodont provinces four potential horizons for inter provincial correlation of permian conodonts are recognized they are in ascending order 1 the first appearance of sweetognathus whitei which is closely related to the last occurrence of carboniferous type conodonts such as streptognathodus and adetognathus 2 the first appearance of neostreptognathodus pequopensis 3 the base of the jinogondolella nankingensis zone and 4 the base of the clarkina postbitteri iranognathus erwini zone the spatial and temporal distribution pattern of permian conodonts suggests that temperature is the primary controlling factor evolution of permian conodont provincialism reveals a glaciation during the asselian and sakmarian a global warming during the artinskian a climate cooling in north pangea during the kungurian a continuation of kungurian climate trends in the guadalupian a relatively minor warming during the wuchiapingian a returned cooling in the changhsingian and lower and middle griesbachian and a global warming in the late griesbachian which ended the permian conodont lineage

melange versus forearc contributions to sedimentation and uplift during rapid denudation of a young banda forearc continent collisional belt abstract new sedimentary geochemistry and petrographic analyses provide the most extensive sedimentary documentation yet of the rapid denudation of the young timor orogen the data from three basins including two widely separated well dated sections of the synorogenic megasequence of timor leste and a re dated dsdp 262 constrain the source and timing of detrital sediment flux during forearc continent collision along the timor sector of the banda arc the exhumed synorogenic piggy back basins formed above a melange unit that developed at the expense of a weak stratigraphic horizon in the mesozoic stratigraphy and was exhumed to the sea floor in latest messinian time following an interval of deep marine chalky marl sedimentation an increasingly muddy sediment flux indicates that the island of timor became emergent and shed sediment by 4 5 ma comparison of exhumed sections with similar patterns in the dsdp262 chemistry suggests that the sediment source was probably located some 50 60 km distant from the basin which is consistent with the aileu region of timor leste that shows an appropriate exhumation history all sedimentation between 4 5 and 3 2 ma was probably derived from a low relief rapidly eroding and mudstone dominated landscape with geochemical affinities to the triassic mudstone derived synorogenic melange the melange unit overlies and surrounds the banda terrane and was presumably structurally emplaced by propagation of a decollement through the triassic rocks during the collision after 3 2 ma sedimentation was dominated by hard rock lithologies of the banda terrane consisting of forearc cover and basement the latter including elements of metamafic rocks and metapelites this phase of sedimentation was accompanied by rapid uplift which may have been partly driven by a transient imbalance between rock uplift and denudation as resistant lithologies emerged from below melange like mudstone previous work has suggested that the timing of collision in timor leste and west timor was substantially different our reevaluation of dsdp 262 facies migration history in the context of the re dating presented here favours a relatively synchronous onset of uplift in both halves of the island but with different partitioning of strain between the foreland and hinterland in each half of the island

lower triassic conodont sequence in chaohu anhui province china and its global correlation abstract the early triassic paleogeographical setting of the chaohu section in china was in a deep part of the yangtze platform and this has resulted in a rather complete lower triassic sequence with rich ammonoid and conodont successions three lower triassic sections west pingdingshan north pingdingshan and south majiashan have been sampled in detail for a systematic conodont study eight conodont zones are recognized in ascending order these are the zones of hindeodus typicalis neogondolella krystyni neospathodus kummeli neospathodus dieneri neospathodus waageni neospathodus pingdingshanensis neospathodus homeri and neospathodus anhuinensis these are correlated with the sequences in north america and other areas of the world the succession provides a good basis for the definition of the global stratotype of the induan olenekian boundary gssp which has been proposed at the base of the neospathodus waageni zone in west pingdingshan seven new species are introduced neospathodus chaohuensis n chii n concavus n eotriangularis n pingdingshanensis n posterolongatus n tongi a new subspecies n waageni eowaageni and three morphotypes of n dieneri

pumping optimization in saltwater intruded coastal aquifers this paper investigates the hydraulic issues of pumping well optimization in saltwater intruded coastal aquifers the well field includes freshwater outflow pumping wells and a recharge canal the objective is to maximize the total pumping rate subject to the constraint of no intrusion of the saltwater front into the wells analytical solutions are presented for one well two well and one well with recharge canal problems for problems involving multiple pumping wells a structured messy genetic algorithm is used to search for the optimal solution

comparison of uranium series radiocarbon and amino acid data from marine molluscs baffin island arctic canada uranium series and sup 14 c dates and the extent of amino acid racemization are reported for 24 marine shell samples from three areas of baffin island arctic canada when the radiometric dates are plotted against the ratio of d alloisoleucene l isoleucene in the shells five broad age groups are recognized the uranium series data indicate that sup 231 pa is incompletely retained in most fossil shells and that sup 230 th is lost from some of the samples therefore their apparent ages are minimum however a few dated samples in each group have yielded useful age results and the minimum ages of the five groups of samples are estimated as 7 000 to 11 000 greater than or equal to70 000 greater than or equal to136 000 greater than or equal to190 000 and 300 000 yr calculated integrated thermal histories based on the epimerization reaction in the mollusc hiatella arctica linne give paleotemperature estimates of around 5 sup o c compared to the present mean annual air temperature of about 11 sup o c

the uranium trend dating method principles and application for southern california marine terrace deposits abstract uranium trend dating is an open system method for age estimation of quaternary sediments using disequilibrium in the 238 u 234 u 230 th decay series the technique has been applied to alluvium colluvium loess till and marine sediments in this study we tested the u trend dating method on calcareous marine terrace deposits from the palos verdes hills and san nicolas island california independent age estimates indicate that terraces in these areas range from 80 ka to greater than 1 0 ma two low terraces on san nicolas island yielded u trend plots that have a clustered array of points and the ages of these deposits are indeterminate or highly suspect middle pleistocene terraces and one early pleistocene terrace on san nicolas island and all terraces on the palos verdes hills gave reasonably linear u trend plots and estimated ages that are stratigraphically consistent and in agreement with independent age estimates we conclude that many marine terrace deposits are suitable for u trend dating but u trend plots must be carefully evaluated and u trend ages should be consistent with independent geologic control

late artinskian early kungurian early permian warming and maximum marine flooding in the east gondwana interior rift timor and western australia and comparisons across east gondwana abstract substantial new information is presented on upper artinskian kungurian deposits in timor leste and in the canning southern carnarvon and northern perth basins of western australia these basins situated between about 35 s and 55 s palaeolatitude formed part of the east gondwana interior rift a precursor to the rift that 100 my later formed the indian ocean in this region timor lay near the main axis of the east gondwana interior rift whereas the western australian basins were marginal splays from the rift axis the main depocentres developed as a result of faulting that was initiated during the late pennsylvanian detailed lithostratigraphic and biostratigraphic analyses have been made on the newly recognized bua bai limestone and the type cribas group in timor the noonkanbah formation in the canning basin the byro group in the merlinleigh sub basin of the southern carnarvon basin and the carynginia formation in the northern perth basin in timor the succession which is highly disrupted by faulting was deposited under open marine conditions probably in a shelf basin setting restricted very shallow water seas flooded the canning basin and the merlinleigh byro irwin sub basins of the southern carnarvon and northern perth basins and had highly variable oxygen levels and salinities typical of estuarine environments a similar pattern of warming and bathymetric change is recognized in all studied basins during the early part of the late artinskian cool conditions prevailed with water temperatures 0 4 c forming sea ice in the merlinleigh byro irwin rift rapid warming during the latter part of the late artinskian was accompanied by maximum marine flooding close to the artinskian kungurian boundary climatic and bathymetric conditions then allowed carbonate mounds with larger fusulines and a variety of algae to develop in the northern part of the rift system and tubiphytes conodonts and brachiopods with tethyan affinities to migrate into the marginal rift basins despite the generally adverse water quality at these depositional sites comparison between the stratigraphic record from the east gondwana interior rift and coeval records from lhasa and sibumasu indicate a similar pattern of climate change during the carboniferous to end cisuralian similar trends probably are present in eastern australia although there is confusion over the correlation of some units

biostratigraphy and palaeobiogeography of lower permian lower kungurian conodonts from the tak fa formation saraburi limestone thailand abstract lower permian lower kungurian conodonts are reported from the indochina block of southeast asia the fauna from the tak fa formation of the saraburi limestone group exposed in limestone hills nnw of khok samrong thailand includes sweetognathus subsymmetricus wang ritter and clark early forms and pseudosweetognathus costatus wang ritter and clark the co occurrence of these species indicates a lower permian age upper half of the lower kungurian for the sampled limestones representative of the mesogondolella siciliensis s subsymmetricus zone of south china sweetognathus and pseudosweetognathus are for the first time reported from the indochina terrane located in the palaeoequatorial belt in the kungurian pseudosweetognathus appears restricted to the kungurian of the south china and indochina terranes thus supporting palaeogeographic reconstructions that isolate these terranes within the palaeo tethys during the kungurian

basalt geochemistry as a test of the tectonic models of timor metamorphosed basic volcanic rocks of permo triassic age occur in several distinct geological formations on timor some are found in para autochthonous units which have been correlated with similar sequences on the australian continental shelf and some occur in apparently allochthonous units which have been correlated with similar sequences in malaya and sumatra analyses of the relatively immobile elements particularly ti zr y nb p and the rare earths from both units revealed that the basalts vary from tholeiitic to mildly alkaline but are all consistent with emplacement in a rift valley or ocean floor setting no difference was detected between the units based on basalt geochemistry no calc alkaline basalts similar to those reported in malaya and sumatra were found and the basaltic suites are regionally distributed so as to cross cut boundaries between the para autochthonous and allochthonous units the geochemistry is consistent with the evolution of all the permo triassic units now on timor as a part of the australian continental margin but requires revision of detailed interpretations in order to be compatible with an exotic origin for the allochthonous units

permian artinskian to wuchapingian conodont biostratigraphy in the tieqiao section laibin area south china permian strata from the tieqiao section jiangnan basin south china contain several distinctive conodont assemblages early permian cisuralian assemblages are dominated by the genera sweetognathus pseudosweetognathus and hindeodus with rare neostreptognathodus and gullodus gondolellids are absent until the end of the kungurian stage in contrast to many parts of the world where gondolellids and neostreptognathodus are the dominant kungurian conodonts a conodont changeover is seen at tieqiao and coincided with a rise of sea level in the late kungurian to the early roadian the previously dominant sweetognathids were replaced by mesogondolellids the middle and late permian guadalupian and lopingian series witnessed dominance of gondolellids jinogondolella and clarkina the common presence of hindeodus and decimation of sweetognathus twenty main and seven subordinate conodont zones are recognised at tieqiao spanning the lower artinskian to the middle wuchiapingian stage the main first appearance datum zones are in ascending order by stage the sweetognathus sw whitei sw toriyamai and sw asymmetrica n sp zones for the artinskian the neostreptognathodus prayi sw guizhouensis sw iranicus sw adjunctus sw subsymmeticus and sw hanzhongensis zones for the kungurian the jinogondolella j nankingensis zone for the roadian the j aserrata zone for the wordian the j postserrata j shannoni j altudaensis j prexuanhanensis j xuanhanensis j granti and clarkina c hongshuiensis zones for the capitanian and the c postbitteri zone and c transcaucasica zone for the base and middle of the wuchiapingian the subordinate interval zones are the pseudosweetognathus ps costatus ps monocornus hindeodus h gulloides pseudohindeodus ramovsi gullodus g sicilianus g duani and h excavates zones in addition three new species gullodus tieqiaoensis n sp pseudohindeodus elliptica n sp and sweetognathus asymmetrica n sp are described age assignments for less common species e g g duani h catalanoi and pseudosweetognathus monocornus etc are reassessed based on a rich conodont collection

the palaeomagnetism of late permian early triassic and late triassic deposits on timor an australian origin summary studies have been carried out on sediments from two formations in western timor a red crinoid bearing limestones of the maubisse formation of late permian early triassic age and b reddish calcilutites and red shales of the aituto formation of late triassic age the crinoid bearing limestones occur in both a non recrystallized and a recrystallized slightly marmorized facies natural remanent magnetization nrm was analysed by means of progressive demagnetization both using alternating magnetic fields and by heating the determination of acquisition remanence and remanent coercive force demonstrated that in a large number of sites high temperature volcanic haematite is the main carrier of remanence a few sites from the non recrystallized maubisse limestones revealed magnetite as the main remanence carrier the recrystallized maubisse limestones were found to have a secondary remanence with a very high coercivity and a high blocking temperature characteristic remanent magnetization chrm directions could be obtained both from the non recrystallized limestones of the maubisse formation and from the aituto formation for the plate tectonic interpretation of the data only the chrm inclination values have been used because of the complicated often chaotic tectonism on timor palaeolatitudinal positions of 39 and 33 have been derived from the late permian early triassic maubisse formation and the late triassic aituto formation respectively this points to the presence on the island of timor of a displaced terrane of australian origin

a multilayered sharp interface model of coupled freshwater and saltwater flow in coastal systems model development and application a quasi three dimensional finite difference model that simulates freshwater and saltwater flow separated by a sharp interface has been developed to study layered coastal aquifer systems the model allows for regional simulation of coastal groundwater conditions including the effects of saltwater dynamics on the freshwater system vertically integrated freshwater and saltwater flow equations incorporating the interface boundary condition are solved within each aquifer leakage through confining layers is calculated by darcy s law accounting for density differences across the layer the locations of the interface tip and toe within grid blocks are tracked by linearly extrapolating the position of the interface the model has been verified using available analytical solutions and experimental results application of the model to the soquel aptos basin santa cruz county california illustrates the use of the quasi three dimensional sharp interface approach for the examination of freshwater saltwater dynamics in regional systems simulation suggests that the interface today is still responding to long term pleistocene sea level fluctuations and has not achieved equilibrium with present day sea level conditions

the permian of timor stratigraphy palaeontology and palaeogeography the permian of timor in the lesser sunda islands has attracted the attention of palaeontologists since the middle of the nineteenth century because of the richness diversity and excellent state of preservation of its fauna these abundant fossil data have been compiled and updated for the present account the permian rocks of timor were deposited on the northern margin of australia at the present time the northern margin of australia in the region of timor is involved in a continent arc collision where australia is colliding with the banda arcs as a result of this collision permian rocks of the australian margin have been disrupted by folding and faulting with the generation of mud matrix melange and uplifted to form part of the island of timor due to this tectonic disruption it has proved difficult to establish a reliable stratigraphy for the permian units on timor especially as the classic fossil collections were obtained largely from the melange or purchased from the local people and do not have adequate stratigraphic control detailed systematic structural stratigraphic and sedimentological studies since the 1960s have provided a firmer stratigraphic and palaeogeographic background for reconsideration of the significance of the classic fossil collections permian rocks on timor belong either to a volcanic carbonate sequence maubisse formation or to a clastic sequence atahoc and cribas formations in which volcanics are less prominent the permian sequences were deposited on australian continental basement which was undergoing extension with spasmodic volcanic activity carbonates of the maubisse formation were deposited on horst blocks and volcanic edifices while clastic sediments of the atahoc and cribas formations were deposited in grabens the clastic sediments are predominantly fine grained derived from a distant siliciclastic source and are interbedded with sediments derived from the volcanics and carbonates of adjacent horst blocks bottom conditions in the graben were often anoxic in the present account events on timor during the permian are related to the regional tectonic context with the northward movement of australia leading to the amelioration of the climate from sub glacial to sub tropical together with the separation of crustal blocks from the northern australian margin to form the meso tethys

provenance of permian triassic gondwana sequence units accreted to the banda arc in the timor region constraints from zircon u pb and hf isotopes abstract analysis of zircons from australian affinity permian triassic units of the timor region yield age distributions with large age peaks at 230 400 ma and 1750 1900 ma which are similar to zircon age spectra found in rocks from ne australia and crustal fragments now found in tibet and se asia it is likely that these terranes which are now widely separated were once part of the northern edge of gondwana near what is now the northern margin of australia the cimmerian block rifted from gondwana in the early permian during the initial formation of the neo tethys ocean the zircon age spectra of the gondwana sequence of ne australia and in the timor region are most similar to the terranes of northern tibet and malaysia further substantiating a similar tectonic affinity a large 1750 1900 ma zircon peak is also very common in other terranes in se asia hf analysis of zircon from the aileu complex in timor and kisar islands shows a bimodal distribution both radiogenically enriched and depleted in the gondwana sequence at 300 ma the magmatic event from which these zircons were derived was likely bimodal i e mafic and felsic this is substantiated by the presence of permian mafic and felsic rocks interlayered with the sandstone used in this study similar rock types and isotopic signatures are also found in permian triassic igneous units throughout the cimmerian continental block the permian triassic rocks of the timor region fill syn rift intra cratonic basins that successfully rifted in the jurassic to form the nw margin of australia this passive continental margin first entered the sunda trench in the timor region at around 7 8 ma causing the permo triassic rocks to accrete to the edge of the asian plate and emerge as a series of mountainous islands in the young banda collision zone eventually the australian continental margin will collide with the southern edge of the asian plate and these gondwanan terranes will rejoin

a latest carboniferous warming spike recorded by a fusulinid rich bioherm in timor leste implications for east gondwana deglaciation abstract during the late paleozoic and early mesozoic timor lay in the northern part of the north south east gondwana rift system along which the western margin of australia later developed discovery of a latest gzhelian bioherm in the central highlands of timor leste has implications for latest carboniferous earliest permian climate history and deglaciation in basins further south in the rift system limestone outcrop of the maubisse formation near the village of kulau is recognized as a bioherm with a massive lower unit including reef framework at the base and a bedded grainstone upper unit the bioherm developed on a basalt substrate in warm shallow water as indicated by photozoan assemblages in the massive lower unit foraminifera belonging to 17 genera are recorded from the bioherm these include representatives of the families biseriamminidae biwaellidae bradyinidae cornuspiridae lasiodiscidae palaeotextulariidae pseudotaxidae ozawainellidae schubertellidae schwagerinidae staffellidae and textrataxidae twenty one species have been referred to known types and 12 species are left in open nomenclature the assemblage probably belongs within the uppermost gzhelian schwagerina robusta ultradaixina bosbytauensis zone although a possible lowest asselian correlation cannot be excluded the bioherm is the oldest carbonate unit so far recorded from the maubisse formation and the oldest sedimentary unit biostratigraphically dated in timor the dominantly heterozoan composition of the skeletal component of the limestone except for the basal photozoan assemblage and the taxonomic diversity of the larger foraminifera suggest a subtropical environment consistent with a paleolatitude of about 40 s the late pennsylvanian was a time of glaciation that in australia is represented by a significant stratigraphic hiatus in basins to the south of timor in the east gondwana rift system the development of the kulau bioherm during the latest gzhelian may have coincided with a global warming spike that led to rapid melting of continental ice sheets and a substantial influx of glacigene sediment alternating diamictite and mudstone in the southern basins

a preliminary case study of potential ceramic raw materials in the aileu area of timor leste abstract the newly independent country of timor leste is located in the eastern half of timor island indonesian archipelago geological studies of the country s mineral resources and extractive activities are practically non existent there is evidence of the exploitation of ceramic raw materials at outcrop level and two small brick kilns nowadays inactive in the dili and aileu areas near aileu there are light coloured silt rich deposits interpreted as overbank deposits interbedded with ancient river terraces post pliocene overlying metamorphic bedrock these sediments are the subject of this study which encompassed geological mapping and preliminary characterisation tectonically the area is a graben preserving alluvium and colluvium deposits five channel samples representative of the silt rich deposits were collected semi quantitative mineralogical analysis shows that the samples are made of illite quartz and kaolinite clays with accessory illite vermiculite interstratified minerals and k feldspar the chemical data show agreement with the estimated mineralogical composition the grain size distribution points to a silt dominated assemblage most samples have a satisfactory extrudability but deficient moulding properties after firing the sampled raw materials form a final product with possible ceramic capability for whiteware production

cisuralian guadalupian conodont sequence from the shaiwa section ziyun guizhou south china abstract a sequence of successive conodont datums and zones for the cisuralian and guadalupian series for the south china region of the equatorial warm water province is proposed based on the shaiwa section ziyun guizhou the seven conodont zones in ascending order are sweetognathus aff whitei zone of artinskian stage a set of three new kungurian zones of sweetognathus guizhouensis zone sweetognathus subsymmetricus zone mesogondolella nashuiensis zone the mesogondolella idahoensis lamberti zone of uppermost kungurian the guadalupian zones of jinogondolella aserrata followed by jinogondolella postserrata the base of the kungurian stage is tentatively defined by the first occurrence of s guizhouensis 174 5 m above the base of the sidazhai formation this suite of conodont datums and zones will help to improve the global correlations of permian strata of the kungurian stage

progress problems and prospects an overview of the guadalupian series of south china and north america abstract the guadalupian epoch is marked by the formation of the pangean supercontinent global sea level change rifting and drifting of the cimmerian continents formation of large igneous provinces and dramatic biotic changes a high resolution biostratigraphic chemostratigraphic and high precision geochronologic framework of this critical transition is fundamental to understanding these events extensive studies of the latest cisuralian and guadalupian series in both south china and north america reveal the same conodont lineages but the conodont interval zones based on jinogondolella within the guadalupian series are slightly diachronous high precision u pb geochronological studies ca id tims method calibrate the base of the guadalupian series base roadian at 273 01 0 14 ma a previously reported age from an ash bed overlying the emeishan flood basalts 259 51 0 21 ma is adopted for the guadalupian lopingian boundary glb based on recently published geochronology and bayesian age modeling from the guadalupian series the base of the capitanian is constrained at 264 28 0 16 ma and the base of the wordian is interpolated to be 266 9 0 4 ma the illawarra reversal is of early middle wordian age both north america and south china possess a distinct negative 13ccarb excursion of 3 5 at the latest kungurian and early roadian lk er cie which coincides with the early stages of a significant 3rd order sea level rise the large end guadalupian 13ccarb negative excursion may have been affected by post depositional diagenesis or a warming event associated with the emeishan volcanism the 87sr 86sr ratios in both regions declined from the latest kungurian to the late capitanian but have different ratios and reveal several fluctuations in the middle guadalupian measured 18oapatite values suggest that the delaware basin was 3 4 c cooler than the eastern yangtze block analysis of a new high resolution database of marine taxa indicates only a minor pre lopingian diversity drop from 261 04 ma to 259 98 ma which coincides with the peak emeishan volcanism the widely perceived end guadalupian mass extinction in north america is evidently masked by and possibly an artefact of a stratigraphic truncation effect due to rapid lithofacies changes from limestone to laminated evaporites with the closure of the west texas basins

motion of the seawater interface in a coastal aquifer by the method of successive steady states abstract the paper describes a method for determining the motion of the seawater interface in a phreatic coastal aquifer during a specified time period in response to changing hydrologic conditions provided a seaward flow of fresh water is maintained everywhere above the interface the method of successive steady states is used leading to an approximate analytical expression which gives the motion of the interface toe during the time period as a function of the initial conditions and the change in freshwater flow to the sea above the toe during the time period sensitivity of the results to values of parameters and to hydrologic conditions is investigated and the results are compared with those obtained by other methods of analysis the motivation for developing the approximate analytical expression for movement of the interface was to facilitate the introduction of seawater intrusion as a criterion in the multiobjective management model for coastal aquifers

the structural setting and tectonic significance of the lolotoi laclubar and aileu metamorphic massifs east timor abstract the lolotoi and laclubar metamorphic massifs of east timor form a part of the lolotoi metamorphic complex based on stratigraphic relationships with the australian affinity parautochthonous stratigraphic succession and structural arguments the lolotoi complex is interpreted as representing australian continental basement entrained into the timor arc continent collision complex by basement involved thrusting the lolotoi complex is not synonymous with the mutis complex defined from west timor which represents allochthonous metamorphic basement derived from the pre collisional banda forearc the aileu complex is a syn collisional metamorphic series with an inverted metamorphic gradient developed beneath overthrust allochthonous peridotite

postglacial early permian late sakmarian early artinskian shallow marine carbonate deposition along a 2000 km transect from timor to west australia abstract late sakmarian to early artinskian early permian carbonate deposition was widespread in the marine intracratonic rift basins that extended into the interior of eastern gondwana from timor in the north to the northern perth basin in the south these basins spanned about 20 of paleolatitude approximately 35 s to 55 s this study describes the type section of the maubisse limestone in timor leste and compares this unit with carbonate sections in the canning basin nura nura member of the poole sandstone the southern carnarvon basin callytharra formation and the northern perth basin fossil cliff member of the holmwood shale the carbonate units have no glacial influence and formed part of a major depositional cycle that in the southern basins overlies glacially influenced strata and lies a short distance below mudstone containing marine fossils and scattered dropstones perhaps indicative of sea ice in the south marine conditions became more restricted and were replaced by coal measures at the top of the depositional sequence in the north the carbonate deposits are possibly bryozoan crinoidal mounds whereas in the southern basins they form laterally continuous relatively thin beds deposited on a very low gradient seafloor at the tops of shale limestone parasequences that thicken upward in parasequence sets all marine deposition within the sequence took place under very shallow inner neritic conditions and the limestones have similar grain composition bryozoan and crinoidal debris dominate the grain assemblages and brachiopod shell fragments foraminifera and ostracod valves are usually common tubiphytes ranged as far south as the southern carnarvon basin albeit rarely but is more common to the north gastropod and bivalve shell debris echinoid spines solitary rugose corals and trilobite carapace elements are rare the uniformity of the grain assemblage and the lack of tropical elements such as larger fusulinid foraminifera colonial corals or dasycladacean algae indicate temperate marine conditions with only a small increase in temperature to the north the depositional cycle containing the studied carbonate deposits represents a warmer phase than the preceding glacially influenced asselian to early sakmarian interval and the subsequent cool phase of the mid artinskian that is followed by significant warming during the late artinskian early kungurian the timing of cooler and warmer intervals in the west australian basins seems out of phase with the eastern australian succession but this may be a problem of chronostratigraphic miscorrelation due to endemic faunas and palynofloras

the triassic of timor lithostratigraphy chronostratigraphy and palaeogeography the palaeontologically rich and lithologically diverse triassic successions of timor provide a key stratigraphic and palaeontological link between northwestern australia and other terranes of former eastern gondwana present day southeast asia timor is now located in the zone of collision between the northern margin of the australian continent and island arc terranes bordering the eurasian plate with the triassic successions exposed in a fold and thrust belt and an extensive melange complex three formal lithostratigraphic units have been defined previously within the main triassic succession in timor niof aitutu and babulu formations with a fourth the wai luli formation primarily jurassic in age but extending down into the triassic the niof formation anisian to ladinian possibly also early triassic is a fine grained deepwater succession succeeded conformably by the aitutu and babulu formations ladinian to norian rhaetian which were deposited contemporaneously with the aitutu formation continuing locally into the lower jurassic the aitutu formation consists of deep shelf limestones interbedded with shales and marls while the babulu formation is a deltaic to turbiditic siliciclastic succession the late triassic to jurassic wai luli formation is characterised by marine shales and marls informal stratigraphic units include the cephalopod limestone facies a rosso ammonitico type deposit which contains an extremely rich fossil fauna particularly ammonoids and ranges through the entire triassic and the fatu limestone and pualaca facies which consists of shallow to marginal marine carbonates mud mounds oolitic limestones and reefs restricted to the late triassic facies diversity was low during the early triassic and anisian but became more pronounced from the ladinian and continuing through the late triassic probably as a consequence of renewed tectonic extension triassic extension was not associated with major volcanism unlike a previous phase of extension in the early permian the cablac limestone formation originally defined as a miocene stratigraphic element is now recognised to be at least partly late triassic early jurassic in age with lithologies comparable to parts of the fatu limestone the stratigraphy of these shallow marine carbonate sequences is clearly in need of rigorous revision but it is not yet possible to suggest appropriate redefined formations

lower middle triassic conodont biostratigraphy of the qingyan section guizhou province southwest china abstract the middle triassic qingyan formation at its type section the qingyan section of guizhou southwest china yields more than 300 species belonging to 17 fossil groups which mark the radiation of benthic organisms following the end permian mass extinction this study intends to establish a primary conodont biostratigraphical succession through the lower and middle triassic sequence at qingyan to provide a time framework for the understanding of the recovery and radiation process from the mass extinction a total of 30 species in 8 conodont genera are stratigraphically significant and assigned to the neospathodus dieneri neospathodus cristagalli neospathodus waageni neospathodus homeri chiosella timorensis and neogondolella cf bulgarica zones in ascending order most conodont zones correlate well with their counterparts recognized from elsewhere in china and even worldwide the first appearance of ns waageni marks the induan olenekian boundary which is placed at the lower middle part of the luolou formation 121 47 m above the permian triassic boundary the olenekian anisian early middle triassic boundary is here defined by the first occurrence of chiosella timorensis at the base of the qingyan formation although no conodonts retrieved from the upper qingyan formation containing the extraordinarily diverse biota i e the qingyan biota stratigraphical correlation with the neighbouring conodont bearing sections in guizhou and the ammonoid zones suggest that the qingyan biota has an age of early late anisian early middle triassic

strategies for successful u th dating of paleolake carbonates an example from the bolivian altiplano we report over 90 u th dates from carbonates deposited around paleolakes on the bolivian altiplano petrographic and chemical data for tufas and the siliciclastic detritus contained within them allow 1 assessment of possible diagenetic effects 2 a development of a strategy for selection of carbonate samples with low initial th contents and 3 assessment of the uncertainty due to initial th this strategy allows us to produce precise u th dates from lacustrine carbonates the principal consideration in dating such carbonates is the composition and quantity of initial th incorporated into the carbonate and additional uncertainty is introduced because this initial th may have two sources in lacustrine deposits isochron plots measured 230th 232th and x ray diffraction and trace element chemistry of silicic residues all favor regional soil and dust as the sole source of initial th in carbonates from the bolivian altiplano a situation that simplifies single sample dating of altiplano carbonates

effect of natural recharge on sea water intrusion in coastal aquifers abstract parametric studies were carried out to investigate the effect of uniform recharge on sea water intrusion into coastal aquifers using a one dimensional finite element model for this purpose uniform recharge over the entire length of intrusion for a wide range of practical aquifers is considered useful relationships have been established between the interface motion and the intensity and duration of uniform recharge these relationships can be used to estimate the repulsion of sea water intrusion owing to rainfall this repulsion under favourable conditions is estimated to reach a maximum of about 5 the effect of uneven distribution of rainfall is demonstrated through an example movement of the interface is also tracked after the cessation of recharge

the permian antitropical fusulinoidean genus monodiexodina distribution taxonomy paleobiogeography and paleoecology all the documented occurrences with illustration of specimens of the permian fusulinoidean genus monodiexodina from a total of 33 areas in 11 regions are reviewed and their taxonomic positions are reexamined in this paper among 17 species including two subspecies of monodiexodina in the current taxonomy the following 10 species are recognized as valid m kattaensis m wanneri m caracorumensis m sutchanica m shiptoni m kumensis m wanganensis m neimongolensis m delicata and m rhaphidoformis in addition species once referred to monodiexodina but now should be excluded from the genus are also investigated in terms of their generic positions in reconstructed mid permian paleomap monodiexodina bearing areas can be restored to either northern or southern middle latitudes between high latitudinal cool cold water climatic realm and paleo tropical warm water realm these two middle latitudinal areas each corresponding to the northern and southern transitional zones respectively can be best interpreted climatologically as mesothermal warm temperate belts in both hemispheres thus suggesting the genus to be a paleobiogeographically typical antitropical fusulinoidean taxon moreover the genus is generally found in a monotypic crowded manner in sandy sediments with their shells being often aligned uni directionally this mode of occurrence of monodiexodina strongly suggests that it was adapted to shallow marine high energy environments which would probably be essentially maintained by the acquisition of highly elongated fusiform subcylindrical shells with well developed polar torsion this morphological feature is adapted to increase septal pores per unit area in polar regions thus increasing possibility to develop more pseudopodia on both sides of test it probably has a functional significance for not only locomotion but also anchoring their tests on the surface of bottom sediments in agitated water conditions the genus itself is considered to be a rather long ranging taxon from the late yakhtashian artinskian to the early midian capitanian it is therefore concluded that monodiexodina had an opportunistic character occurring repeatedly only when favorable high energy conditions such as sand shoal appeared in warm temperate climatic belts in both hemispheres monodiexodina originated in the southern transitional zone from an elongated eoparafusulina stock at late early permian around late artinskian time it flourished in southern middle latitudinal areas in latest early and early middle permian time the genus then migrated to the northern hemisphere northern transitional zone by some dispersion mechanism at around the early middle permian and prevailed there during the remaining period of the middle permian