measurements of katabatic winds between dome c and dumont d urville dumont d urville on the antarctic coast is an area well known for the presence of strong katabatic winds since the austral summer 1979 80 a us french joint experiment has been investigating the katabatic wind in this region in early 1980 three automatic weather stations aws were installed along a trajectory from dome charlie to dumont d urville measurements from these stations include air pressure temperature wind speed and direction at ground level only to supplement these data with information regarding the vertical structure and the advective changes in the katabatic flow two airborne missions were undertaken in november 1980 along a route from dome charlie dome c to dumont d urville

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

petrogenesis of malaysian granitoids in the southeast asian tin belt part 1 geochemical and sr nd isotopic characteristics the malaysian granitoids of the southeast asian tin belt have been traditionally divided into a permian to late triassic i type dominated arc related eastern province indochina terrane and a late triassic s type dominated collision related main range province sibumasu terrane separated by the bentong raub paleo tethyan suture that closed in the late triassic the present study however shows that this model is oversimplified and that the direct application of chappell and white s 1974 i and s type classification cannot account for many of the characteristics shared by malaysian granitoids despite being commonly hornblende bearing as is typical for i type granites the roof zones of the eastern province granites are hornblende free in addition the main range province granitoids contain insignificant primary muscovite and are dominated by biotite granites mineralogically similar to many of the plutons of the eastern province in general the malaysian granitoids from both provinces are more enriched in high field strength elements than typical cordilleran i and s type granitoids the mineralogy and geochemistry of the eastern province granitoids and their relationship with contemporaneous volcanics confirm their i type nature the bulk liquid lines of descent of both granitic provinces largely overlap with one another sr nd isotopic data further demonstrate that the malaysian granitoids especially those of the main range were hybridized melts derived from two end member source regions one of which is isotopically similar to the kontum orthoamphibolites and the other akin to the kontum paragneisses of the indochina block however there are differences in the source rocks for the two provinces and it is suggested in this paper that these are related to differing proportions of igneous and sedimentary protoliths the incorporation of sedimentary sourced melts in the eastern province is insignificant which allowed the granites in this belt to maintain their i type nature the presence of minor primary tin mineralization in the eastern province compared to the much more significant tin endowment in the main range is considered to reflect the incorporation of a smaller proportion of sedimentary protolith in the melt products of the former

a modified seismic reflection approach for engineering geology investigation in fractured rock zones abstract delineating soil rock interface is critical for geotechnical and tunnel site investigations in engineering geology in singapore we also need to draw attention to local faults and fractured rock zones because the regional geology of peninsular malaysia and singapore contains some minor steep and brittle faults propagating at some areas in the island city in addition to drilling boreholes seismic reflection survey is a viable option to mitigate the uncertainties in areas without boreholes however the current practice of seismic reflection still follows the methods used in the petroleum exploration community this investigation reviews and modifies the seismic reflection approach specifically customized for geotechnical and tunnel site investigation which is partly different from petroleum exploration we demonstrate the modified approach through a field testing in singapore the resultant image from the field test fairly captures the soil rock interface and it is validated based on the vertically drilled boreholes a local fault or a fracture rock zone is also identified in the migrated image the extent and location match with the record of horizontal directional coring hdc this addresses the concern of fracture rock zone raised from the regional and local geology and provides useful information for geotechnical and tunnel engineers in addition we further discuss the general challenges of using the modified seismic reflection approach this work aims to help the geotechnical and tunnel community better understand the non invasive seismic reflection survey

the petrology of greek brown coals abstract results are given in the petrography of greek coals collected from most of the major coal bearing basins in greece rank was determined by measuring reflectances on the maceral varieties eu ulminite a and eu ulminite b and on the maceral textinite reflectances obtained from these components indicate a coalification stage of brown coal for all samples within this group of samples there is however a fairly wide scatter of reflectance values indicating for some of them the transition zone from peat to brown coal and for others a coalification stage close to the transition into bituminous coals reflectances obtained from eu ulminite a and eu ulminite b were found to correlate well with chemical rank parameters such as volatile matter and calorific value composition was determined by maceral analysis the coals are in general characterized by low amounts of macerals of the inertinite group low to intermediate amounts of macerals of the liptinite group and high amounts of macerals of the huminite group within the latter group densinite attrinite eu ulminite and textinite make up the bulk of the samples typical macerals observed in the coals are illustrated by two black and white and three colour plates cluster analysis based on maceral distribution mineral matter and reflectance indicates that the samples studied can be divided into three major groups the first one is dominated by eu ulminite and densinite with relatively high reflectances the second is dominated by attrinite textinite and texto ulminite with somewhat lower reflectances the third is represented by a single sample in which textinite and resinite are the most abundant macerals this sample also has the lowest reflectance

the forcing of antarctic katabatic winds abstract the temporal and spatial development of katabatic winds along an idealized slope representative of anmtarctic terrain is examined using a hydrostatic two dimensional primitive equation model with explicit longwave radiation parameterization a detailed diagnosis is made of a simulation in which katabatic flow develops from rest due to the strong radiational cooling of the underlying surface significant thermodynamic and dynamic differences are seen between the gravity driven flows over the gently sloping interior and over the steep ice slopes near the coast the strongest temperature inversions and largest static stabilities are found over the interior of the continent although the net cooling of the katabatic layer and magnitude of the downslope directed horizontal pressure gradient force are greatest at the coast the interior is characterized by low rossby number quasi geostrophic type flows while more intense near antitriptic winds occur at the coast model results are in reasonable agr

deep to shallow marine sedimentology and impact of volcanism within the middle triassic palaeo tethyan semantan basin singapore abstract the middle triassic pulau ayer chawan formation is a predominantly deep marine occasionally shallow marine sedimentary succession deposited in the singapore sector of the palaeo tethyan semantan basin the formation provides an important record of the dynamic interplay between a siliciclastic sedimentary system and the products of an adjacent active volcanic arc it is characterised by six sub environments including deep marine turbidite fan deep marine background sedimentation subaqueous debris cone shallow marine volcanically sourced turbidite fan and hyaloclastite mound or ridge turbidite fan deposits preserve the input of both siliciclastic and volcaniclastic sediments from the shelf transported into the deep marine environment by a suite of subaqueous sediment gravity flow processes including turbidity currents mixed flow types hybrid event beds concentrated and hyper concentrated sediment gravity flows and debris flows thick heterolithic successions of debrites were likely sourced through regular collapse of an unstable shelf the presence of hybrid event beds encountered within the deep marine turbidite fans supports a slope that was out of grade and may have been actively retreating towards the hinterland together these factors suggest regional scale uplift of the eastern margins of the semantan basin during triassic times most likely facilitated through volcanic activity in the adjacent palaeo tethys sukhothai arc evidence for contemporaneous arc related magmatism includes ubiquitous volcaniclastic sedimentary rocks within formation including pyroclastic density current deposits and perhaps more strikingly through the hyaloclastites of the nanyang member the hyaloclastites formed through quenching of magmas delivered into the deep marine setting from a series of sub sea vents or mounds

numerical simulation of winter katabatic winds from west antarctica crossing siple coast and the ross ice shelf abstract twenty four hour numerical simulations of wintertime surface winds under clear sky conditions over the west antarctic ice sheet and its vicinity are performed using a hydrostatic three dimensional primitive equation model two initial states are examined a state of rest and a prescribed pressure field associated with katabatic winds from west antarctica propagating across the ross ice shelf the antarctic katabatic winds are mainly due to the strong radiative cooling of the ice slopes the west antarctic terrain is different from that of east antarctica in two respects its mean elevation is much lower and the slope in the interior is steeper than near the margin at siple coast the simulated surface wind regime reveals confluence zones just inland from the coast and diffluence zones around the crest of the terrain the model results suggest that the continuation of katabatic winds beyond coastal confluence zones which are sustained by cold air drainage in the interior has an important impa

tectonic evolution of the malay peninsula abstract the malay peninsula is characterised by three north south belts the western central and eastern belts based on distinct differences in stratigraphy structure magmatism geophysical signatures and geological evolution the western belt forms part of the sibumasu terrane derived from the nw australian gondwana margin in the late early permian the central and eastern belts represent the sukhothai arc constructed in the late carboniferous early permian on the margin of the indochina block derived from the gondwana margin in the early devonian this arc was then separated from indochina by back arc spreading in the permian the bentong raub suture zone forms the boundary between the sibumasu terrane western belt and sukhothai arc central and eastern belts and preserves remnants of the devonian permian main palaeo tethys ocean basin destroyed by subduction beneath the indochina block sukhothai arc which produced the permian triassic andesitic volcanism and i type granitoids observed in the central and eastern belts of the malay peninsula the collision between sibumasu and the sukhothai arc began in early triassic times and was completed by the late triassic triassic cherts turbidites and conglomerates of the semanggol formation were deposited in a fore deep basin constructed on the leading edge of sibumasu and the uplifted accretionary complex collisional crustal thickening coupled with slab break off and rising hot asthenosphere produced the main range late triassic earliest jurassic s type granitoids that intrude the western belt and bentong raub suture zone the sukhothai back arc basin opened in the early permian and collapsed and closed in the middle late triassic marine sedimentation ceased in the late triassic in the malay peninsula due to tectonic and isostatic uplift and jurassic cretaceous continental red beds form a cover sequence a significant late cretaceous tectono thermal event affected the peninsula with major faulting granitoid intrusion and re setting of palaeomagnetic signatures

review and update of the applications of organic petrology part 1 geological applications abstract organic petrology developed as coal petrology at the beginning of the 20th century dedicated mainly to the study of coals because of their utilization in industry coal petrology was then considered a branch of coal science later with the development of specialized nomenclature classification of coal components and the standardization and improvement of analytical microscopical methods this discipline expanded in interests and name becoming organic petrology organic petrology carries a broader context being as well a tool applied in the study of dispersed organic matter in sedimentary rocks due to its importance in exploration for fossil fuel resources at present organic petrology is a discipline widely recognized for its role in fundamental and applied research with respect to both coal utilization and in geosciences throughout the 20th century several important monographs have been published on the discipline of organic petrology including stach s textbook of coal petrology 1st edition 1935 2nd 1975 3rd 1982 updated as the more general organic petrology by taylor et al 1998 more recently the text applied coal petrology the role of petrology in coal utilization was published by suarez ruiz and crelling 2008 this review is the first in a two part review series that describes and updates the role of organic petrology in geosciences a second part complementing this one and focused on the applications of organic petrology to other scientific fields will follow

the granites of the southeast asian tin belt four granite provinces have been delineated each with its own distinctive pattern of mineralization 1 the main range province endogenous greisen bordered vein swarms of cassiterite and wolframite 2 the eastern province magnetite cassiterite skarns base metal sulphides with antimony in thailand 3 the western peninsular thailand burma province endogenous greisen bordered vein swarms and pegmatites of cassiterite and wolframite 4 the north thailand migmatitic province endogenous vein and skarn replacement scheelite and fluorite deposits with some tin and local antimony in all provinces but particularly in the main range granitoids designated as two phase variants have been recognized where xenocrysts and xenoliths of coarse primary texture granite are enclosed in and corroded by an invasive equigranular quartzo feldspathic matrix these rocks form an essential part of the granite sequence in all provinces and have probably resulted from the infiltration and disruption of the host granite by late stage magmatic fluids whole rock geochemistry from peninsular malaysia shows that the granites from the main range and eastern provinces comprise two contrasted suites which correspond approximately to the i and s type categories advocated by chappell white 1974 in addition it is shown that individual plutons within batholiths in the two provinces have distinctive geochemical parameters variation diagrams of plutons having the intrusive sequence primary texture granite two phase granite microgranite show linear trends with increasing sio 2 na 2 o rb w sn and u and decreasing sr ba th and all other major elements

an analysis of strong wind events simulated in a gcm near casey in the antarctic abstract strong wind events occurring near casey antarctica in a long july gcm simulation have been studied to determine the relative roles played by the synoptic situation and the katabatic flow in producing these episodes it has been found that the events are associated with strong katabatic and strong gradient flow operating together both components are found to increase threefold on average for these strong winds and although the geostrophic flow is the stronger it rarely produces strong winds without katabatic flow becoming stronger than it is in the mean the two wind components do not flow in the same direction indeed there is some cancellation between them since katabatic flow acts in a predominant downslope direction while the geostrophic wind acts across slope the stronger geostrophic flow is associated with higher than average pressures over the continent and the approach of a strong cyclonic system toward the mast and a blocking system downstream the anomalous synoptic patterns lea

succession of depositional environments in the neogene basin at aliveri evia greece abstract the neogene lignite bearing sequence in the southern part of the aliveri kymi basin was studied with regard to sedimentology palynology and coal petrology in order to establish the type and succession of environments involved and to compare them with modern analogues initial sediments of the prinias group were deposited in a wide shallow depression by means of a low competent drainage system which formed sandy alluvial fans interfan areas and ephemeral lakes as well as sand flats and vegetated mudflats in lateral sequences from the basin margins to a central perennial lake succeeding sediments of the prinias group were formed under the influence of the rising lake level in algal marsh various peat forming and open lake environments sediments of the koustoumalou group were deposited by a highly competent surficial drainage system in alluvial fan to braided and meandering fluvial environments this drainage system followed the south north trending axis of an asymmetrical graben while debris flows moved in from the steep flanks to the east

genesis of granitoid batholiths of peninsular malaysia and implications for models of crustal evolution evidence from a ndsr isotopic and upb zircon study nd sr and u pb isotopic data for the late triassic west coast province batholiths and permian to triassic east coast province batholiths of peninsular malaysia allow estimates of the ages of the crustal fragments comprising the peninsula to be made initial nd and sr values for granitoids from the west coast province range from 6 to 10 and 160 0 716 to 660 0 751 respectively nd model ages calculated based on a depleted mantle evolution model tdmnd range from 1300 ma to 1800 ma and are in general agreement with the mid proterozoic upper intersection ages of u pb zircon reverse discordia 1500 1700 ma initial nd and sr values for granitoids from the east coast province range from 0 8 to 6 and 10 0 705 to 130 0 714 respectively calculated tdmnd ages of 900 1400 ma for these granitoids are comparable to two u pb zircon reverse discordia intercepts that yield 800 ma and 1350 ma the general agreement of u pb zircon inheritance ages and tdmnd ages are interpreted to correspond to the proterozoic crust formation ages of the continental fragments represented by the west coast and east coast batholithic provinces mid proterozoic 1300 1900 ma crust formation ages are commonly shown by other phanerozoic continental margin plutonic and volcanic belts the ubiquitous mid proterozoic crust formation ages and the absence of archaean signatures suggest voluminous juvenile additions to the continental crust in the mid proterozoic such ages at continental margins would imply that many continental blocks had achieved very much their present day extent by the mid proterozoic

pliocene lignites from apofysis mine amynteo basin northwestern greece petrographical characteristics and depositional environment coal petrological investigation along with proximate and elemental analyses were undertaken to determine the petrographic characteristics of the apofysis lignites amynteo basin northwestern greece and their depositional environment eight samples representing different lignite beds of the apofysis deposit were collected from a borehole the apofysis lignites have an eu ulminite b reflectance of rr 0 22 and in terms of lithotype belong to matrix soft brown coals huminite is the most abundant maceral group and consists mostly of humodetrinite inertinite has relatively low percentages whereas liptinite concentrations are low in the lower lignite beds and higher in the upper ones ternary plots and facies indices were employed in order to investigate the palaeoenvironment the depositional environment of the apofysis lignites is not definitely ascribed to a forest swamp or a reed marsh environment the high ash content of the analysed samples is a clear indication of a topogenous setting low tissue preservation index tpi and high gelification index gi values are observed high alkalinity and strongly reducing conditions may be inferred from the presence of syngenetic framboidal pyrite the low tpi values which indicate high bacterial activity and thus high ph conditions and the preservation of gastropod shells and chlorophyllinite high gi indicates a constant influx of calcium rich waters into the coal swamp the apofysis lignite deposit may be interpreted to be autochthonous to hypoautochthonous the peat accumulation was governed by a high groundwater level wet telmatic to limno telmatic facies and a moderate subsidence rate

the geology and coal petrology of a miocene lignite profile at meliadi mine katerini greece abstract the present study describes vertical variations in petrographic composition of a miocene lignitebearing succession from the moschopotamus basin greece the lignite beds are described megascopically in terms of lithotypes and microscopically by maceral contents examination of lithotype variations within the seams and the distribution of facies critical macerals such as humotelinite and humodetrinite and the relatively low inertinite contents suggest a formation of the miocene lignites as reed marsh to wet forest type swamps in a lower delta plain depositional setting reflectances measured on the maceral type eu ulminite b range from 0 36 to 0 42 r random placing the meliadi coals into a transition zone from lignite to subbituminous coal

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

the igneous rocks of singapore new insights to palaeozoic and mesozoic assembly of the sukhothai arc abstract six plutons of granitic to gabbroic rocks have been recognised in the poorly exposed ground of north and east singapore using new data from borehole cores and field observations five of the plutons were emplaced sequentially during the period 285 230 ma and these have been grouped within a single parent unit bukit timah centre in a new lithodemic framework for singapore these plutons record the development of early permian to triassic arc related magmatism towards the southern end of the sukhothai arc system of thailand peninsular malaysia and indonesia compositional trends in the plutons record decreasing crustal contribution as the arc matured the volcanosedimentary succession underlying southwest singapore records contemporaneous deposition in the forearc basin and includes pyroclastic units of sufficient thickness and extent to be assigned member status in a new lithostratigraphical framework for singapore the largest pyroclastic unit which is 150 m thick developed as volcanic activity peaked at c 242 ma and is correlated with a large probably caldera forming eruption of one of the permo triassic plutons the composition typology and age of the bukit timah centre plutons confirm their affinity with eastern belt intrusions of the eastern province one of three granitoid provinces in southeast asia and support a widely accepted model that eastern province granitoids formed in an andean type setting as palaeo tethys crust descended beneath the indochina east malaya block widespread development of hydrothermal tuffisite in the permo triassic intrusions is correlated tentatively with rapid uplift following slab breakoff when arc activity ceased in the singapore region in the interval c 230 205 ma a sixth pluton much younger than and unrelated to the bukit timah centre was emplaced in northeast singapore in the upper cretaceous

dynamical constraints on katabatic wind cessation in adelie land antarctica the katabatic wind events observed in the coastal zone of adelie land antarctica on 27 november and 3 december 1985 are simulated with a hydrostatic mesoscale atmospheric model coupled to a snow moder the diurnal cycle of insolation is strong the main difference in the forcing between the two events is the large scale wind which is weak on 27 november and moderate on 3 december in both cases temperature and wind are characterized by well marked diurnal cycles in particular katabatic winds blow during nighttime and upslope winds during daytime in both cases the katabatic airstream slows down progressively over the ocean consequently continental air piles up and this generates a pool of cold air responsible for a pressure gradient force opposing the katabatic wind an amplification of the slowing down results when in the morning insolation increases the surface inversion weakens but the influence of the cold air pool increases the katabatic how starts to decay over the coastal zone and then retreats progressively toward the ice sheet interior when the large scale wind is weak the surface warming is sufficient for generating an additional upslope bouyancy force and anabatic flow develops over the ice sheet in the afternoon when the large scare wind is moderate and downslope the pilling up of cold air is important and this has a dramatic impact on the flow a sharp spatial transition is generated between downslope and upslope winds over the ocean this discontinuity moves toward the ice sheet interior in the morning and is responsible for the sudden cessation of the katabatic flow seen by static observers the results of the simulations are used in order to refine a simple parameterization of antarctic katabatic winds

transitional i s type characteristic in the main range granite peninsular malaysia the dominantly triassic main range granite of peninsular malaysia that occurs west of the paleo tethyan bentong raub suture zone was regarded exclusively as an s type granite the main range dominantly biotite granites are of batholithic proportion and host one of the world s largest tin provinces the s type characteristics include high initial 87sr 86sr isotope ratios 0 710 a narrow range in silica presence of ilmenite and occasional cordierite and andalusite and the presence of pelitic or quartzose meta sedimentary xenoliths however the present review shows that the main range granites also have many features that are more characteristic of i type granites such as the very large scale of plutonism the presence of primary titanite and amphibole occurrence of hornblende bearing mafic enclaves increasing peraluminosity towards the more differentiated end members of the suite and decreasing p2o5 with increasing sio2 contents the moderately peraluminous nature of the bulk main range granite without containing cordierite fe mg garnet or sillimanite is consistent with derivation from a meta sedimentary protolith that was itself undersaturated with respect to al2sio5

interaction of katabatic flow with local thermal effects in a coastal region of adelie land east antarctica katabatic flows largely dominate the climate of the adelie land coastal region a detailed climatological data analysis of dumont d urville has been conducted results of this study support the idea that katabatic flow can be locally enhanced by the diurnal cycle of solar insolation and the temperature contrast between the continent and the ocean the interaction between katabatic wind and local thermal effects is expressed in terms of scale analysis except for surface stress all terms in the momentum equation for a katabatic flow in a coastal region of antarctica can reach the same order of magnitude the local circulation then is the result of a relatively tenuous force balance which can be disrupted even by a weak perturbation of any term to estimate the effect of the temperature contrast between the ocean and the continent on the katabatic flow two numerical experiments have been conducted the simulations consider an ocean free of sea ice representative of the summer months and another winter case with the ocean covered by thick sea ice these simulations show that with the ocean free of sea ice the katabatic flows extend only a limited distance over the open ocean during the day due to the local thermal effects with the ocean covered by sea ice the katabatic winds are not constrained and extend a considerable distance offshore

petrological and organic geochemical characteristics of coal samples from florina lava moschopotamos and kalavryta coal fields greece abstract coal samples from florina vevi lava moschopotamos and kalavryta basins greece have been subjected to petrographic and organic geochemical analysis the reflectance of the samples ranged from 0 26 to 0 42 which ranks them as soft brown coals and sub bituminous c coals lower reflectance values were encountered in the florina and kalavryta coals whereas higher values were obtained for lava and moschopotamos samples maceral composition of the samples from the florina area shows a high concentration of textinite a and texto ulminite a the samples from the lava and moschopotamos area are comparatively rich in humodetrinite samples from florina are rich in resinite whereas samples from lava are rich in liptodetrinite rock eval pyrolysis data show that the samples from florina and kalavryta have generally high hi si and s2 and low t max values the coal samples from moschopotamos and lava show the opposite having low hi s1 and s2 values these distinct differences are related to the maceral composition tissue rich in resinitic material and rank of the coals gas chromatography of the saturate fraction indicates that the samples from the lava and moschopotamos are rich in n alkanes from n c 23 to n c 33 in contrast the samples from florina are rich in diterpanes whereas those from kalavryta are rich in sesquiterpenoids gas chromatography mass spectrometry of the saturate fraction reveals that the diterpenoids present in the lignites from kalavryta are derivatives of abietanic acid and pimaric acid which are found in pinaceae the lignites from florina mainly contain the diterpane phyllocladane which implies an input from cupressaceae and or taxodiacaea the difference in the composition of these xylitic lignites may be attributed to differences in gymnosperm input as a response to climatic change as the kalavryta coals are of pliocene age whereas the florina coals are of miocene age the study suggests that the petrology and organic geochemistry of these coals are related to the different peat forming plant communities that were present in the florina kalavryta lava and moschopotamos basins a mainly non woody angiosperm dominated vegetation made up the peat that went to form the coal deposits of lava and moschopotamos while the florina and kalavryta lignites were formed by peats derived mainly from gymnosperms

petrogenesis of malaysian granitoids in the southeast asian tin belt part 2 u pb zircon geochronology and tectonic model in our complementary geochemical study part 1 the malaysian granitoids of the southeast asian tin belt were divided into a middle permian to late triassic i type dominated eastern province indochina terrane and a triassic to early jurassic transitional i s type main range province sibumasu terrane separated by the bentong raub suture zone which closed in the late triassic previous geochronology has relied on only a few u pb zircon ages together with k ar and whole rock rb sr ages that may not accurately record true magmatic ages we pre sent 39 new high precision u pb zircon ion microprobe ages from granitoids and vol canics across the malay peninsula our results show that ages from the eastern province granitoids span 289 220 ma with those from the main range province granitoids being entirely late triassic spanning 227 201 ma a general westerly younging magmatic trend across the malay peninsula is considered to refl ect steepening and roll back of the bentong raub subduction zone during progressive closure of paleo tethys the youngest ages of subduction related granites in the eastern province roughly coincide with the youngest ages of marine sedimentary rocks along the paleo tethyan suture zone our petrogenetic and u pb zircon age data support models that relate the eastern province granites to pre collisional andean type magmatism and the western main range province granites to syn and post collisional crustal melting of sibumasu crust during the late triassic tin mineralization was mainly associated with the latter phase of magmatism two alternative tectonic models are discussed to explain the triassic evolution of the malay peninsula the fi rst involves a second late triassic to jurassic or early cretaceous east dipping subduction zone west of sibumasu where subduction related hornblende and biotite bearing granites along sibumasu are paired with main range crustal melt tinbearing granites analogous to the bolivia cordilleran tin bearing granite belt the second model involves westward underthrusting of indochina beneath the west malaya main range province resulting in crustal thickening and formation of tin bearing granites of the main ranges cretaceous granitoids are also present locally in singapore ubin diorite on tioman island in the noring pluton of the stong complex eastern province and along the sibumasu terrane in southwest thailand and burma myanmar refl ecting localized crustal melting

simulation of atmospheric circulation during the gimex 91 experiment using a meso γ primitive equations model a meso gamma scale atmospheric model has been used to simulate atmospheric circulations observed during the greenland ice margin experiment gimex the simulations shown here are two dimensional and cover the 12 13 july 1991 period a typical summer situation in this area the synoptic scale wind forcing is included the tundra topography is assumed to be either flat or averaged over a 50 km wide cross section centered on the gimex transect simulated wind temperature humidity and turbulent fluxes compare reasonably well with available observations the simulated heat used to melt snow or ice is also shown the sensitivity of the model results to the synoptic scale wind forcing is significant the impact of a tundra much warmer than the ocean on the ice sheet melting is discussed it is found that weak easterly synoptic scale winds are able to overwhelm this impact especially when the tundra is assumed to be flat

continental scale simulation of the antarctic katabatic wind regime abstract katabatic winds are a common feature of the lower antarctic atmosphere although these drainage flows are quite shallow there is increasing evidence that the low level circulations are an important component in establishing large scale tropospheric motions in the high southern latitudes three dimensional numerical simulations of the antarctic katabatic wind regime and attendant tropospheric circulations have been conducted over the entire continent to depict the topographically forced drainage patterns in the near surface layer of the atmosphere results of the simulation enable a mapping of katabatic wind potential and identification of coastal regions which may experience anomalously intense katabatic winds a large upper level cyclonic circulation forms rapidly in response to the evolving katabatic wind structure in the lower atmosphere suggesting that the drainage circulations are an important component in prescribing the resulting resulting circumpolar vortex these results imply that som

coal facies studies in greece in greece coal forming conditions prevailed mainly during neogene and quaternary times in several intermontane and paralic basins and resulted in the formation of significant peat and lignite deposits the economically recoverable lignite reserves are 3 9 gt and the annual production mainly for power generation exceeds 65 mt

the geology and coal petrology of a pleistocene lignite profile at horemi mine megalopolis basin peloponnese southern greece abstract the present study describes the geology coal petrology and geochemistry of a pleistocene coal bearing succession at horemi mine megalopolis basin southern greece within a 45 m interval 9 coal seams are exposed ranging in thickness from 20 cm to 10 m reflectances measured on the maceral type eu ulminite b range between 0 24 and 0 31 mean r random this indicates a coalification stage in the transition zone between peat and lignite rank of the a s t m classification for the horemi coals petrographic studies demonstrated the immature nature of these coals and the low degree of compaction during diagenesis compositionally the horemi coals are characterized by low amounts 5 3 vol of the inertinite group macerals moderate amounts 11 9 vol of liptinite group macerals and very high amounts 82 8 vol of the huminite group macerals on average and mineral matter free basis within the latter group densinite attrinite and ulminite make up the bulk of the samples results from proximate and ultimate analysis gave on average 53 7 bed moisture and 37 3 ash 45 8 volatiles and 18 1 fixed carbon d b calorific value determinations vary between 1805 and 5470 kcal kg mineral matter is high varying within the range 20 8 51 9 vol identifiable mineral constituents include quartz anhydrite illite feldspars calcite gypsum and chlorite and minor amounts of barite and pyrite reflectances obtained from ulminite were found to be negatively correlated with volatile matter whereas there is a trend for a positive correlation of them with calorific values

palaeogeography of late triassic red beds in singapore and the indosinian orogeny abstract a red bed facies of the upper triassic jurong formation has been logged on sentosa island singapore an overall coarsening and thickening upward pattern is well developed the lower part of the section is dominated by purple red massive to finely laminated illite smectite kaolin rich mudstones containing thin discontinuous lenses of fine sandstone marked by low angle lamination and small ripples one dinosaur like foot print has been discovered in a loose block of red mudstone it is concluded that this is a lacustrine sequence and it is proposed to name the lake lake sentosa the upper part of the sequence consists of flat laminated to trough cross bedded medium grained sandstone and granule to cobble conglomerates alternating with purple red mudstone the mudstone sandstone packages are arranged in decametre scale coarsening upward cycles the channelling and decimetre scale cross bedding characterising the sandstone and conglomeratic beds is evidence for deposition by flashy fluvial flood processes possibly feeding into the lake as a fresh water delta one possible dinosaur trackway in granule size conglomerate has been located detrital zircon u pb ages vary from 2 7 ba to 209 ma with significant populations at 245 ma and 220 ma these ages throw light on the timing of the indosinian orogeny the molasse red beds of the jurong formation were deposited in a half graben formed in the hangingwall of the bukit timah fault when central peninsular malaysia went into extension following the climax of the indosinian orogeny in the late triassic

surface pressure change through loewe s phenomena and katabatic flow jumps study of two cases in adelie land antarctica abstract preliminary results from the 1985 iago interaction atmosphere glace ocean field programme in adelie land antarctica allow for a detailed description of several katabatic events especially of their vertical structure and time and space variations several loewe s phenomena where a sudden transition from shooting to tranquil flow takes place have been observed two of them have been well documented and are shown here for both cases as observed at a downstream station close to the coast the mean wind speed suddenly decreased from about 20 m s 1 to almost zero while a large pressure increase was recorded 5 7 hpa on 3 december 1985 and 2 1 hpa on 18 december 1985 this paper aims at explaining such large surface pressure changes as more usual approaches cannot for both cases it is found that the flow is stratified upwards with a surface well mixed cold air layer a very stable capping inversion layer an overlying unstable layer thickening from upstream to downstream and a stable transi

the deep crust beneath island arcs inherited zircons reveal a gondwana continental fragment beneath east java indonesia abstract inherited zircons in cenozoic sedimentary and igneous rocks of east java range in age from archean to cenozoic the distribution of zircons reveals two different basement types at depth the igneous rocks of the early cenozoic arc found along the southeast coast contain only archean to cambrian zircons in contrast clastic rocks of north and west of east java contain cretaceous zircons which are not found in the arc rocks to the south the presence of cretaceous zircons supports previous interpretations that much of east java is underlain by arc and ophiolitic rocks accreted to the southeast asian margin during cretaceous subduction however such accreted material cannot account for the older zircons the age populations of archean to cambrian zircons in the arc rocks are similar to gondwana crust we interpret the east java early cenozoic arc to be underlain by a continental fragment of gondwana origin and not cretaceous material as previously suggested melts rising through the crust feeding the early cenozoic arc picked up the ancient zircons through assimilation or partial melting we suggest a western australian origin for the fragment which rifted from australia during the mesozoic and collided with southeast asia resulting in the termination of cretaceous subduction continental crust was therefore present at depth beneath the arc in south java when cenozoic subduction began in the eocene

late cretaceous coal overlying karstic bauxite deposits in the parnassus ghiona unit central greece coal characteristics and depositional environment abstract the pera lakkos coal located on top of bauxite deposits in the ghiona mining district central greece is the only known mesozoic late cretaceous coal in the country it was derived from herbaceous plants and algae growing in mildly brackish mires that formed behind a barrier system during a regression of the sea on a karstified limestone partly filled in with bauxitic detritus petrological mineralogical and geochemical data point to the predominance of reducing conditions and intense organic matter degradation in the palaeomires o c vs h c and oi vs hi plots based on elemental analysis and rock eval data characterize kerogen types i ii this reflects the relatively high liptinite content of the coal besides kerogen composition o c vs h c plot for the pera lakkos coals is in accordance with a catagenesis stage of maturation in contrast with vitrinite reflectance and t max from rock eval pyrolysis which indicate the onset of oil window maturation stage suppression of vitrinite reflectance should be considered and the high liptinite content corroborates this hypothesis despite some favourable aspects for petroleum generation presented by the pera lakkos coal its maximum thickness up to 50 cm points to a restricted potential for petroleum generation coal oxidation took place either during the late stage of peat formation due to wave action accompanying the subsequent marine transgression or epigenetically after the emergence of the whole sequence due to percolation of drainage waters both options are also supported by the ree shale normalized profiles which demonstrate an upwards depletion in the coal layer oxidation also affected pyrite included in the coal this led to the formation of acidic sulfate rich solutions which percolated downwards resulting in bleaching of the upper part of the underlying bauxite

granitic magmatism basement ages and provenance indicators in the malay peninsula insights from detrital zircon u pb and hf isotope data abstract the malay peninsula lies on two continental blocks sibumasu and east malaya which are intruded by granitoids in two provinces the main range and eastern previous models propose that permian triassic granitoids are subduction related and syn to post collisional we present 752 u pb analyses that were carried out on zircons from river sands in the malay peninsula of these 243 grains were selected for hf isotope analyses our data suggest a more complex sibumasu east malaya collision history 176hf 177hfi ratios reveal that permian triassic zircons were sourced from three magmatic suites a permian crustally derived granitoids b early middle triassic granitoids with mixed mantle crust sources and c late triassic crustally derived granitoids this suggests three permian triassic episodes of magmatism in the malay peninsula two of which occurred in the eastern province although the exact timing of the sibumasu east malaya collision remains unresolved current data suggest that it occurred before the late triassic probably in late permian early triassic our data also indicate that sibumasu and east malaya basements are chronologically heterogeneous but predominantly of proterozoic age some basement may be neoarchaean but there is no evidence for basement older than 2 8 ga finally we show that hf isotope signatures of triassic zircons can be used as provenance indicators

u pb zircon geochronology of early permian to late triassic rocks from singapore and johor a plate tectonic reinterpretation article i nfo the results of u pb zircon geochronology of permian to middle triassic granitoids from singapore and neighbouring johor are presented rhyolite from pulau sibu is 276 5 ma gabbros from singapore give ages of 260 2 to 249 2 ma granites from singapore give ages from 249 2 to 230 6 ma and rhyolite from telkuma gives an age of 238 2 ma u pb detrital zircon age spectra from a late triassic conglomerate from singapore show carboniferous mid dle triassic and late triassic spikes at 350 245 and 217 ma respectively these new data when combined with published u pb zircon ages allow a revision of the plate tectonic evolution of the malaysian peninsula region a tin bearing magmatic arc evolved in the eastern malaysian peninsula part of indochina from the early permian to the middle triassic when the palaeo tethys ocean was subducted and sibumasu continental lithosphere was rifted from pangea this opened up the neo tethys ocean that the granitoid ages show a progressive decrease in age from pulau sibu 276 5 ma to singapore 230 6 ma suggests that during this andean type orogenic phase the subduction zone rolled back and steepened causing the locus of mainly i type magmatism to migrate from east to west in present day coordinates across the eastern and central belts and stretch the lithosphere as it did so in the late triassic sibumasu collided with indochina causing the western belt sibumasu to over thrust the central belt indochina along the bentong raub suture the lower half of the thickened crust formally the tin bearing indochina plate was partially melted and pre dominantly s type tin bearing granites were intruded into the upper crust formally sibumasu this late triassic collisional phase is the indosinian orogeny in peninsular malaysia

tectonic evolution of the sibumasu indochina terrane collision zone in thailand and malaysia constraints from new u pb zircon chronology of se asian tin granitoids three principal granite provinces are defined across se asia as follows 1 the western thailand myanmar burma province consists of hornblende biotite i type granodiorite granites and felsic biotite k feldspar garnet tourmaline granites associated with abundant tin mineralization in greisen type veins new ion microprobe u pb dating results from phuket island show zircon core ages of 212 2 and 214 2 ma and a thermal overprint with rims of 81 2 1 2 and 85 75 ma 2 the north thailand west malaya main range province has mainly s type biotite granites and abundant tin mineralization resulting from crustal thickening following collision of the sibumasu plate with indochina during the mid triassic biotite granites around kuala lumpur contain extremely u rich zircons up to 38000 ppm that yield ages of 215 7 and 210 7 ma 3 the east malaya province consists of dominantly permian triassic i type hornblende biotite granites but with subordinate s type plutons and a type syenite gabbros biotite k feldspar granites from tioman island off the east coast of malaysia also yield a zircon age of 80 1 ma showing cretaceous magmatism in common with province 1 geological and u pb geochronological data suggest that two east dipping in present day coordinates subduction zones are required during the triassic one along the bentong raub palaeo tethyan suture and the other west of the phuket burma province 1 belt supplementary material a full description of u pb analytical methods used and data tables are available at www geolsoc org uk sup18523

surface winds over the antarctic continent a review surface winds over antarctica often classified as katabatic are intimately related to the orientation and steepness of the underlying ice terrain such flows result primarily from the strong radiational cooling of the sloping ice surface which creates a downslope directed horizontal pressure gradient force it is possible to diagnose the time averaged near surface streamline patterns of cold air drainage currents using recently compiled detailed antarctic ice topography maps and appropriate estimates of the strength of the surface temperature inversion the resulting streamlines agree with available observations and illustrate the high degree of nonuniformity of gravity driven flows off the ice sheets in certain interior sections negatively buoyant air from a large catchment area drains through a restricted section of coastline such confluence zones represent regions of enhanced supplies of cold air and are shown to be related to anomalously strong katabatic winds implications for sea ice formation are discussed

organic petrographical mineralogical and geochemical features of the achlada and mavropigi lignite deposits nw macedonia greece abstract the achlada and mavropigi lignite deposits in northern greece provide the main coal source for the next generation of greek power plants a comparative characterization of these two lignite deposits is presented covering the coal rank and the features of the maceral components based on detailed coal petrography and the mineralogical and geochemical features of the coals and their ashes based on xrf and xrd analyses the data are used to interpret the palaeoenvironments of the lignite beds as well as factors that may affect their burnout behavior both deposits have a lignite c rank the mavropigi lignite is mainly a matrix lignite lithotype whereas the achlada deposit consists both of matrix and xylite rich lithotypes the achlada lignite was formed in a fluviatile environment mainly in the abandoned channels of a meandering river system during flooding periods hence it is enriched in inorganic matter with ash values 30 wt the mavropigi lignite formed in a reed marsh environment under limno telmatic conditions and displays ash values the inorganic matter of the two deposits is different in composition due to the contrasting environments and these differences should be taken into account in optimizing their utilization for power production a preliminary assessment indicates that the achlada lignite may have more favorable slagging and fouling properties than the mavropigi lignite although experimental studies are required for more solid conclusions to be reached

a new quaternary stratigraphy of the kallang river basin singapore implications for urban development and geotechnical engineering in singapore abstract the quaternary stratigraphy of many coastal areas in southeast asia is poorly understood developing a detailed framework is important as many coastal cities are built on these unconsolidated coastal marine sediments this study reviews the current understanding of quaternary deposits in the kallang river basin singapore using 161 boreholes to create 14 cross sections and a 3d geological model the dataset is augmented with a 38 5 m long sediment core obtained from marina south 1 2726 n 103 8653 e and a previous record from geylang 1 3137 n 103 8917 e to provide age constraints and stratigraphic reference a new quaternary stratigraphic framework for singapore is presented here constrained by new radiocarbon and optically stimulated luminescence osl dating and identify palaeo features that record the geomorphic and sedimentary evolution of the basin fluvial deposits of pleistocene age are uncomfortably overlain by littoral tidal sands and subsequently marine clay possibly during marine isotope stage mis 5e 125 ka bp subsequent subaerial exposure and weathering of the marine clay during the last interglacial produced a stiff clay layer the stiff clay is unconformably overlain by holocene transgressive sands and peats from 9 5 ka bp followed by marine clays with a maximum basal age of 9 2 ka bp regressive sandy peat units were subsequently deposited beginning 6 ka bp here the new quaternary stratigraphic framework for singapore is presented as well as provide important constraints on the regional sea level history and geomorphological evolution of singapore s southern coast from mis 5e to present the work also highlights the complexities of geoengineering work in such subsurface terranes