benthonic foraminiferal assemblages and microfacies analysis of paleocene eocene carbonate rocks in the kastamonu region northern turkey the kastamonu region nw turkey is known for its rich foraminiferal marine biota and variety of deposits from paleocene to eocene times the focus of this study is on the foraminiferal assemblages and microfacies analysis of the sediments usually paleocene shallow water limestones overlie maastrichtian rocks conformably they are characterized by benthic foraminifera such as laffitteina mengaudi astre anomalina sp eponides sp rotalia sp mississippina sp haurenidae in the lower strata and numerous rotaliid such as pseudocuvillierina sireli inan rotalia perovalis terquem r trochidiformis lamarck kathina selveri smout kathina major smout smoutina subspherica sirel miscellanea primitiva rahaghi in the upper strata the eocene clayey limestones limestones and marls which generally conformably overlie the paleocene are commonly characterized by benthic foraminifera of orbitolites complanatus lamarck asterigerina rotula kaufmann gyroidinella magna le calvez fabiania cassis oppenheim nummulites minervensis schaub nummulites burdigalensis de la harpe nummulites millecaput boubee assilina placentula deshayes assilina exponens sowerby microfacies analyses of the paleocene eocene carbonate rocks were carried out with respect to the distribution of depositional components and biota the danian selandian and thanetian units are characterized by reefal organic buildup shelf lagoon shelf and tidal flat paleoenvironments the ilerdian units are represented by reefal and shelf lagoon environments while the cuisian units are characterized by shelf lagoon and deep shelf settings the lutetian units indicate platform margin through fore slope to deep marine shelf paleoenvironments

lightning associated with the 1992 eruptions of crater peak mount spurr volcano alaska abstract lightning occurred associated with the ash clouds of all three eruptions of mt spurr volcano in 1992 lightning was detected on seismograms as simultaneous spikes and simultaneous gain ranging a feature that normally lowers the gain at a station when the signal level begins to saturate spikes had typical durations of 0 04 0 05 s using uniform criteria we found 28 lightning flashes in the june 27th eruption 29 in the august 18th eruption and three in the september 17th eruption we measured peak voltages on station rso 94 km ssw to determine the relative strengths of lightning and found that the august lightning was strongest june weakest and september intermediate based on relative signal strengths at different stations we found evidence for different lightning geometries between the june and august eruptions during which prevailing winds blew the ash clouds to the north and east respectively for all three eruptions the first lightning was recorded 21 26 min after the onset of the eruption suggesting that charge separation occurred in the convecting cloud rather than at the vent data recorded by a bureau of land management lightning detection system for the august eruption showed negative polarities for the first 12 recorded flashes and a positive polarity for the last this suggests a charge separation based on particle size in which negative charge is found for larger particles which fall first and positive charge remains on smaller particles which remain suspended longer all three eruptions had similar durations of 3 5 4 h and tephra volumes of 44 56 million cubic meters the august eruption however produced stronger volcanic tremor 30 cm2 reduced displacement as compared with 16 cm2 for june and greater gas 400 120 kt so2 for august and 200 60 kt for june thus lightning strength correlates with both tremor amplitude and magmatic gas content the august eruption occurred during the lightest winds so the ash cloud and charge separation were vertically oriented and favored cloud to ground lightning the september eruption occurred during the coldest and driest atmospheric conditions which may explain the small amount of lightning in general volcanic lightning is important because it can help confirm that explosive eruptions are in progress although the value of the information may be limited by the long delay from eruption onset to first lightning and the variability of eruptive and atmospheric conditions

calcification of encrusting aragonitic algae peyssonneliaceae implications for the origin of late paleozoic reefs and cements abstract encrusting aragonitic calcareous algae of the family peyssonneliaceae are the largest group of calcified red algae outside the well known mg calcite corallinaceae they are distributed worldwide are most heavily calcified in temperate and tropical waters and grow as prone but arched sheets on soft mud substrates on hard rock surfaces as extensive bridge like networks between corals in reefs and as concentric layers in nodules calcification is entirely aragonitic species specific and both intracellular and extracellular below the thallus as a hypobasal layer the hypobasal layer develops outside the tissue as an encrustation of small aragonite botryoids attached to the lower surface between rhyzoids and on living plants it may exceed the thickness of the thallus calcification ranges from nonexistent in some cold water forms to thallus calcification only to both thallus and hypobasal calcification to species in which the thallus is noncalcified but there is a hypobasal layer of aragonite botryoids although the confirmed fossil range of this family extends only to the early cretaceous striking similarities between these aragonitic forms and some late paleozoic phylloid algae suggest that they may be closely related their ability to grow on soft mud substrates and form structures composed of irregular arched sheets with extensive pore space as well as their brittle nature so susceptible to fragmentation are all characteristics of mound forming fossil phylloid algae the hypobasal layer of botryoidal aragonite developed while the plant is still growing could easily act as a nucleation site for further epitaxial submarine precipitation thus explaining the common association of paleozoic phylloid algae and extensive fossil reef cements that resemble botryoidal aragonite the presence of hypobasal botryoidal aragonite on plants with a noncalcified thallus raises the possibility that some fossil reef cements may be related to now vanished algae

digital image based numerical modeling method for prediction of inhomogeneous rock failure abstract this paper presents a two dimensional digital image based numerical modeling method for prediction of inhomogeneous rock failure behavior under loadings actual inhomogeneities of granitic rocks are extracted from color images of the granite cross sections they are represented as the internal spatial distribution of three main granite minerals quartz feldspar and biotite the actual mineral spatial distribution on granite cross section is then incorporated into conventional numerical software packages to examine the rock failures under loading some digital image processing algorithms are presented to isolate and identify the main internal minerals and their distribution from color digital images a simple method is proposed to transform the actual image data into vector data for generation of finite meshes or grids the vector data are used directly as uniform square element meshes or grids that can be inputted into the existing software packages the finite difference software package flac is used as an example for the present investigation the conventional mohr coulomb and tensile stress failure criteria are used to examine the failure behavior of a circular granite cross section under the conventional brazilian indirect tensile test loading conditions the numerical results indicate that the vertical tensile crack initiates in a biotite located near the geometrical center of the granite cross section and the actual spatial distribution of the three minerals plays an important role in modifying the propagation pattern of the tensile crack from its theoretical position at the central vertical diameter of a homogeneous circular cross section the numerically predicted failure load and tensile strength values for inhomogeneous granite are much lower than the expected values

rhodolith assemblages from the lower tortonian carbonate ramp of menorca spain environmental and paleoclimatic implications abstract lower tortonian distally steepened carbonate ramp of menorca mostly consists of foramol and rhodalgal facies deposited in inner middle ramp ramp slope and outer ramp settings red algae are abundant from the middle ramp to the lower part of the slope and their taxonomic assemblages are clearly related to the bathymetric position melobesioids percentage increases basinward passing from 55 8 in the middle ramp to 97 in the toe of slope mastophoroids are more abundant in the middle ramp 43 1 and decrease toward deeper paleoenvironments 1 2 lithophylloids and sporolithaceans appear as accessory components from the middle ramp to slope settings the percentage of melobesioids and mastophoroids observed in the middle ramp suggest that growth of the rhodoliths started in a water depth below 10 20 m the deepest occurrence of the rhodoliths is in the ramp slope environment where the dominance of melobesioids and the low percentage of shallower water subfamily suggests a water depth range of 70 to 100 m shape and structure of rhodoliths are indicative of high energy conditions in all ramp settings and they do not reflect a decrease in hydrodynamic energy related to water depth increase these conditions are related to the presence of unidirectional currents that produced cross bedded grainstones existing in the middle ramp ramp slope and at the toe of the ramp slope settings the high percentage of mastophoroids in the shallowest environments and the presence of lithoporella and sporolithon in the coralline assemblages suggests that carbonate production took place in tropical waters

paleocene coralgal reefs of the western pyrenean basin northern spain new evidence supporting an earliest paleogene recovery of reefal ecosystems abstract the rate of recovery of photic reefal ecosystems after the cretaceous tertiary crisis is controversial most reports from earlier authors concluded that paleogene reef systems did not completely recover from that crisis at least until oligocene miocene times several other authors however have pointed out that such conclusion was biased by poor preservation and or inaccessibility of many early paleogene successions and that the recovery of reefs might have been a faster process the latter possibility is here strongly supported with data from the pyrenean basin where paleocene shallow water carbonate deposits are thickly developed and outcrop widely five growth phases of reef development have been recognized and age dated with calcareous nannofossils which together define a complete sequence of expansion reduction of reef ecosystems during the paleocene epoch reef growth phase 1 early danian lower middle np3 calcareous nannofossil zone the initial step of that sequence demonstrates that coral dominated reef systems came back into existence less than 2 ma after the k t boundary a comparatively short time considering the magnitude of the end cretaceous biological crisis the climax of the sequence is recorded by growth phase 3 late danian np4 zone when a thick barrier reef complex was developed which was at least 200 km in length but probably much larger and made up by a well diversified coralgal assemblage reef growth phases 4 and 5 early and middle thanetian np6 to np8 zones were characterized by low relief reef banks dominated by encrusting calcareous algae and had less well diversified coral assemblages features that point to a deterioration of environmental conditions tentatively interpreted in terms of a climatic cooling reef bioconstruction almost disappeared in the pyrenean basin during late thanetian times although in all likelihood this is a regional effect of no evolutionary relevance the new data suggest that the cenozoic recovery of reefs was rapid but punctuated with a phase of important reef expansion already in the late danian

rio tinto sedimentary mineral assemblages a terrestrial perspective that suggests some formation pathways of phyllosilicates on mars abstract the presence of extensive phyllosilicate deposits from the early noachian of mars are often interpreted as having formed from neutral to subalkaline solutions in this paper we examine the rio tinto fluvial basin an early mars analog that hosts clay production and sedimentation along the entire course of the river at rio tinto phyllosilicate minerals including clays and micas are sourced by volcanosedimentary bedrock of rhyolitic and andesitic composition affected by carboniferous hydrothermal alteration pleistocene to modern acidic weathering of those materials chemically altered the volcanic and sedimentary materials to k na clay montmorillonite smectites kaolinite assemblages in paleosoils and fractures while physical weathering degrades phyllosilicates more resistant to acidic attack during the wet season phyllosilicates are eroded transported and deposited from both acidic headwaters and neutral tributaries during the dry season sulfates and nanophase oxyhydroxides co precipitate late summer storms that cause fast flooding events mix illite quartz feldspars iron oxides and other minerals in fluvial deposits where these minerals are stabilized and aggrade until the following wet season as a result chemical precipitates primary phyllosilicates and secondary clays form mineral admixtures that explain the compositional diversity of the fluvial deposits these deposits reveal the persistence of smectites whose occurrence is explained given that the reaction kinetics under acidic conditions of degradation is lowered by seasonal discharges of the river the longevity of phyllosilicate minerals within fluvial deposits depends on climatic and geochemical conditions and processes which are in turn are correlated to temperature persistence of water hydrological cycling hydrogeochemistry and composition of the source materials in the basement these parameters are universal and have to be characterized in order to understand the distribution of mineral composition on any planetary surface including mars

onshore to offshore reconstruction of the messinian erosion surface in western sardinia italy implications for the messinian salinity crisis new outcrops in the sinis peninsula sardinia italy allow a detailed description of the messinian erosion surface the correlation between outcrops industrial seismic data and data collected offshore oristano from a recent cruise permits reconstruction of the geometry of this surface from presently emerged interfluves to the deep canyons offshore with onshore an eroded karstic plateau presently cropping out over a 20 km 5 km area well preserved karst structures occur locally and can form several metres high reliefs the southernmost edge of the plateau is limited by a cliff the karstic plateau and the cliff are sealed by transgressive deposits of pliocene age offshore an interfluve zone with a mostly flat and low angle dipping plateau westward dissected by paleovalleys which were identified down to a depth of 2000 m in the oristano gulf messinian paleovalleys were also identified the capo san marco paleocliff was probably located on the edge of a canyon onshore only one major erosion surface was identified located at the top the messinian sequence offshore this surface extends down to the abyssal plain the surface was emplaced above deposits related to the terminal carbonate complex this indicates that the marginal evaporites are older than the major drawdown of the mediterranean sea level the major drawdown is related to the deposition of the deep evaporites

neogene coralline algal growth forms and their palaeoenvironments in the almanzora river valley almeria s e spain abstract the almanzora river valley is an elongate e w depression containing mainly neogene sediments during the late tortonian several horizons of crustose coralline algae developed in three distinct sedimentary contexts a on coastal platforms and talus slopes b on fan deltas and c associated with corals in patch reefs growing at the furthermost extremes of coastal fan deltas in the former two cases the predominant growths are as rhodoliths associated with mobile substrates in the coastal systems an increase in depth results in a change in both the morphology and the composition of the rhodoliths with depth there is a significant increase in the diversity of algal species and a concomitant increase in the size of the algal covering compared to the nucleus and thus the morphology of the rhodolith depends less and less on the shape of the nucleus itself the massive crusts and columns which mark the limit of development of the shallow water rhodoliths in the deeper examples are covered by branching and thin leafy laminar growths in the fan deltas the development of the rhodoliths is similar to that of the deeper coastal zones in the patch reefs the specific composition of the algal associations changes somewhat and the growths developed on a stable substrate under low energy conditions are mainly vertical branches arising from thin crusts

the dagpazari carbonate platform mut basin southern turkey facies and environmental reconstruction of a coral reef system during the middle miocene climatic optimum abstract plate tectonics and climate change have deeply influenced the evolution of coral reef systems of the mediterranean during the miocene most of this information is based on studies of coral reefs from the western and central sectors of the mediterranean this study reports facies analyses sr isotope stratigraphy and environmental reconstructions of the dagpazari coral reef system located within the mut basin in southern turkey stratigraphic correlations and sr isotope ratios on several oyster shells date the dagpazari reef to the early langhian ten different facies have been recognized and their arrangement has led to the identification of two main depositional units interpretation of the biotic associations indicates that the dagpazari depositional system developed constantly within the euphotic zone the reef framework was mainly built by massive faviid and poritid zooxanthellate corals whereas loose grain sediments were essentially produced by halimeda coralline red algae or influenced by the presence of seagrass colonizations this study highlights for the first time the great importance of halimeda as sediment producer in the eastern mediterranean coral reef systems this role is related to the common occurrence of halimeda plates within almost all the reef facies but especially to the presence of large in situ bioherms dominated by the algal segments dagpazari langhian halimeda bioherms also represent the oldest of these structures so far recorded in the fossil record the development of the dagpazari platform was mainly controlled by eustatic fluctuations of the sea level and by the morphology of the antecedent substrate in particular the occurrence of a pre existent topographic high promoted the constant presence of shallow water environments throughout the depositional history of the reef system with the production of euphotic carbonates both landward and basinward and the consequent formation of a small elliptical platform 87sr 86sr ages place the dagpazari reef system exactly within the middle miocene climatic optimum phase the most recent warm phase of the earth this suggests that zooxanthellate corals were able to exert their reef building capacity in shallow water settings even during periods of global warming thus being not exclusively an adaptation to cooling climates as proposed in the recent debates

evidence for a 3 45 billion year old magnetic remanence hints of an ancient geodynamo from conglomerates of south africa 1 paleomagnetic and rock magnetic analyses of 3445 million year old dacite conglomerate clasts and parent body rocks from the barberton greenstone belt south africa define two dominant components of magnetization one component unblocked at low temperature is an overprint acquired 180 million years ago the other component is unblocked at high temperatures and passes a conglomerate test indicating that this component is older than the depositional age of the conglomerate 3416 ma the high unblocking temperature component shows scatter in the parent body rocks that can be explained by the effects of modern lightning strikes archean overprinting and the presence of multidomain magnetic grains that are conducive to carrying secondary magnetizations alternatively this scatter can be explained by exotic magnetization scenarios in the absence of a dynamo including magnetization by an external field related to solar wind interaction with the atmosphere such exotic mechanisms can be tested with the acquisition of paleointensity data while more scattered than paleomagnetic data recording the more recent geomagnetic field the high unblocking temperature component in the dacite parent body shows some consistency and the simplest explanation of the data is that they reflect a geodynamo 3445 million years ago

carbonate lithofacies as paleolatitude indicators problems and limitations abstract detailed study of miocene carbonates in the mediterranean region and their analogues on modern carbonate shelves in the mediterranean sea brazil and other areas reveals at least three major types of carbonate platform lithofacies in addition to the classic tropical coral reef chlorozoan lithofacies a chloralgal lithofacies similar to the chlorozoan but without hermatypic corals b rhodalgal lithofacies characterized by abundant encrusting coralline algae and c molechfor lithofacies consisting of benthic foraminifers molluscs echinoids bryozoans and barnacles these carbonate lithofacies present complex distribution patterns seemingly related primarily to latitude and depth that control water temperature although other factors e g water circulation river discharge suspended sediment controlling water salinity and temperature nutrient content light penetration etc also play important roles chloralgal and rhodalgal lithofacies can be considered two transitional terms between the two end members the chlorozoan lithofacies which characterizes shallow tropical shelves and the molechfor lithofacies which characterizes colder and or deeper areas detailed textural and sequential analysis are required for satisfactory interpretation of these lithofacies in ancient rocks

morpho structural heterogeneity of shallow water coralligenous in a pleistocene marine terrace le castella italy abstract coralligenous is the most volumetrically significant type of autochthonous carbonate build up in the mediterranean but its range of morphological variability at the macroscale and potential link with environmental factors have not been fully documented well preserved examples of coralligenous are exposed in shallow marine carbonate deposits from the upper pleistocene le castella marine terrace southern italy the coralligenous build ups occur in the lower part of an unconformity bounded transgressive regressive sequence they show high structural and morphological heterogeneity in terms of framework type and build up size over a distance of several hundred meters in northern exposures coralligenous forms banks up to 4 m high with a dense coralline dominated framework laterally adjacent to paleo channels devoid of build ups and filled by coeval infra circalittoral biogenic packstone to the south build ups are smaller up to 1 8 m high with an open algal framework and local predominance of the coral cladocora caespitosa as primary framework builder at both locations the most important framework building coralline species is mesophyllum philippii titanoderma pustulatum also occurs analysis of sedimentary structures paleo topographic indicators faunal composition of associated mollusk assemblages and predominance of m philippii suggest the algal builds ups grew within a shallow water possibly infralittoral setting competing for space with other biocoenoses suitable substrate availability in the form of conglomerate blocks or shell accumulations was the primary factor controlling the inception and spatial distribution of coralligenous differences in hydrodynamism and water turbidity determined variability in size and internal composition between the northern and southern locations to the south abundant supply of fine suspended sediment resulted in smaller build ups with more open framework the growth of which was terminated abruptly by sediment burial eventually relative sea level fall during regression prevented further growth of the coralligenous even in the northern area this study contributes to a better understanding of the relationship between coralligenous morphology and environmental factors highlighting the role of suitable substrate availability turbidity and sediment burial in influencing spatial and temporal variability of coralligenous assemblages

late paleocene early eocene tethyan carbonate platform evolution a response to long and short term paleoclimatic change abstract the early paleogene experienced the most pronounced long term warming trend of the cenozoic superimposed by transient warming events such as the paleocene eocene thermal maximum petm the consequences of climatic perturbations and associated changes on the evolution of carbonate platforms are relatively unexplored today modern carbonate platforms especially coral reefs are highly sensitive to environmental and climatic change which raises the question how sub tropical reef systems of the early paleogene reacted to gradual and sudden global warming eutrophication of shelf areas enhanced co 2 levels in an ocean with low mg ca ratios the answer to this question may help to investigate the fate of modern coral reef systems in times of global warming and rising co 2 levels here we present a synthesis of tethyan carbonate platform evolution in the early paleogene 59 55 ma concentrating on coral reefs and larger foraminifera two important organism groups during this time interval we discuss and evaluate the importance of the intrinsic and extrinsic factors leading to the dissimilar evolution of both groups during the early paleogene detailed analyses of two carbonate platform areas at low egypt and middle spain paleolatitudes and comparison with faunal patterns of coeval platforms retrieved from the literature led to the distinction of three evolutionary stages in the late paleocene to early eocene tethys stage i late paleocene coralgal dominated platforms at low to middle paleolatitudes stage ii a transitional latest paleocene platform stage with coralgal reefs dominating at middle paleolatitudes and larger foraminifera dominated miscellanea ranikothalia assilina platforms at low paleolatitudes and stage iii early eocene larger foraminifera dominated alveolina orbitolites nummulites platforms at low to middle paleolatitudes the onset of the latter prominent larger foraminifera dominated platform correlates with the paleocene eocene thermal maximum the causes for the change from coral dominated platforms to larger foraminifera dominated platforms are multilayered the decline of coralgal reefs in low latitudes during platform stage ii is related to overall warming leading to sea surface temperatures in the tropics beyond the maximum temperature range of corals the overall low occurrence of coral reefs in the paleogene might be related to the presence of a calcite sea at the same time larger foraminifera started to flourish after their near extinction at the cretaceous paleogene boundary the demise of coralgal reefs at all studied paleolatitudes in platform stage iii can be founded on the effects of the petm resulting in short term warming eutrophic conditions on the shelves and acidification of the oceans hampering the growth of aragonitic corals while calcitic larger foraminifera flourished in the absence of other successful carbonate producing organisms larger foraminifera were able to take over the role as the dominant carbonate platform inhabitant leading to a stepwise tethyan platform stage evolution around the paleocene eocene boundary this szenario might be also effective for threatened coral reef sites

temperature and biotic crises in the marine realm climatic change has been a prominent cause of marine mass extinction but areal restriction of seafloor during global regression has not late eocene and pliocene pleistocene cooling for example caused major extinctions but profound global oligocene and pleistocene regressions had little or no direct effect on benthic diversity recurrent themes of pre cenozoic marine crises suggest that global temperature change also served as a major and perhaps dominant agent of extinction in these events 1 mass extinctions have frequently been concentrated in the tropics which seem to have become a refrigerated trap from which there has been no escape biotas previously occupying high latitudes have shifted equatorward to replace disappearing tropical biotas 2 some crises were not instantaneous but followed protracted and pulsatile temporal patterns as would be predicted for complex global climatic crises 3 several mass extinctions coincided with recognized intervals of climatic cooling

crustose algal frameworks from the eocene alpine foreland abstract upper eocene algal limestones of the eastern alpine foreland in austria contain three different types of crustose algal frameworks these reveal several similarities with the present day coralligene de plateau of the mediterranean sea but the framework types differ in the crust forming algal taxa the sedimentary regime and the environmental setting 1 the coralline coral frameworks develop from siliciclastic sediments and show a succession from coverstones to bindstone to cruststone initiation of this framework in a siliciclastic regime is only possible because of the occurrence of neogoniolithon sp a species that is able to grow on fine grained soft substrate the onset of a dense crustose framework was related to the reduced sediment input and the occurrence of lithothamnion sp which is able to form cruststones 2 pure coralline algal frameworks are restricted to cruststones dominated by both lithothamnion sp and neogoniolithon sp they formed on top of maerl megaripples during calm periods and shed crustose fragments towards depressions which allowed framework progradation 3 peyssonneliacean dominated frameworks occur with intercalations of coralline algal crusts they formed in muddy environments interpreted as protected depressions between maerl dunes we found that crustose frameworks are controlled by three factors 1 sediment input low input favors the growth of frameworks while coarser grained siliciclastics cause burial of initial algal crusts terrigenous mud influences water turbidity and thus favors the occurrence of peyssonneliacean algae 2 taxonomic composition framework formation requires the existence of crustose algal taxa which are able to grow directly on fine grained soft substrate neogoniolithon sp polystrata alba or to encrust and stabilize coarse grained particles lithothamnion sp and or to form multiple successions of dense crusts lithothamnion sp p alba phymatolithon sp characteristically encrusts corals but it does not contribute to the frameworks surprisingly algae do never form protuberances within the frameworks even if they show protuberant growth forms in maerl sediment 3 substrate stability as a function of substrate composition and hydrodynamic energy due to their occurrence on maerl bottoms and the lack of evidence for submarine hardgrounds the settlement of crustose buildups requires low tidal current activity and or wave agitation

recovery of marine primary producers after the cretaceous tertiary mass extinction paleocene calcareous red algae from the iberian peninsula abstract calcareous red algae corallines solenoporaceans and peyssonneliaceans are major contributors to paleocene platform deposits in the pyrenean basin n spain and prebetic zone betic cordillera se spain the earliest danian middle thanetian time interval in the pyrenean basin is represented by four depositional sequences the ma da earliest danian da 1 early danian da 2 late danian and th 1 selandian mid thanetian sequences from bottom to top this precise chronostratigraphic framework allows an accurate assessment of the recovery of these calcareous algal groups after the cretaceous tertiary k t mass extinction calcareous algae are recorded shortly after the k t boundary 0 2 0 3 ma after the k t although the richness of identifiable species remains low during the danian 9 species in the earliest danian 9 species in the early danian and 11 species in the late danian in addition no change in taxonomic composition is observed in this interval since approximately the same algal species occur in all three danian sequences the same low species richness 11 species and species composition is observed in the danian algal assemblages of the betic cordillera however this low level of diversification changes radically in the selandian mid thanetian interval when 29 species are recorded together with the increase in species richness the taxonomic composition also changes since 19 species of corallines are recorded for the first time in the th 1 sequence therefore it can be deduced that species diversity recovery due to a significant radiation of corallines was delayed 6 ma after the end cretaceous event the recovery of corallines during the paleocene shows a characteristic depth dependent pattern throughout the danian middle thanetian interval representatives of the family hapalidiaceae subfamily melobesioideae and plants of the family sporolithaceae largely dominate the algal assemblages in the deep water outer platform settings as they do in present day seas members of these two groups are also the most abundant coralline algae in the paleocene reef and back reef paleoenvironments indicating that the shallowest and best illuminated areas were occupied by algal groups that in modern tropical seas mainly occur in relatively deep habitats this suggests that all platform habitats were re occupied after the end cretaceous event by the groups that selectively survived the extinction only after a time interval of about 6 ma did the habitat distribution of coralline groups change to its modern patterns the subfamilies most abundant in present day shallow tropical waters that is mastophoroideae and lithophylloideae for the first time account for more than 1 of the algal assemblages in the thanetian and even then they remain very minor components these shallow water coralline groups were affected more intensively by the k t extinction event accounting for the delay in their recovery in their preferred shallow water habitats shallow water lithophylloids and geniculate corallines have not been found in danian sequences

stratigraphic modelling of carbonate platform to basin sediments maastrichtian to paleocene in the eastern desert egypt abstract in the galala mountains of the eastern desert egypt carbonate platform and basin deposits have excellent exposure these exposures show a late campanian early paleocene rimmed platform evolving into a late paleocene distally steepened ramp we modelled the evolution of the platform basin transition from the maastrichtian to selandian 68 7 59 ma with the 2 d stratigraphic simulation program phil and compared the modelled results with outcrop sections stratigraphic facies and environmental data are summarized and operate as input and control parameters for the computer simulation the most important parameters that control the depositional geometries of the late cretaceous mixed carbonate siliciclastic platform and the paleogene carbonate platform are changes in relative sea level sediment flux and initial topography the simulation provides an understanding of platform growth and slope to basin deposition particularly in areas of the platform that are poorly exposed or have been eroded moreover the simulated geologic parameters like lithology overall thickness and palaeowater depth closely resemble field and laboratory measurements of the individual sections in an earlier study the maastrichtian slope angle was calculated to be 5 8 and this was confirmed in this study in this earlier study also the timing of the transition from a rimmed platform to a distally steepened ramp was established to be during latest maastrichtian early paleocene the present study shows that the rimmed platform persisted at least until the late paleocene 59 ma as indicated by the relatively high slope angle of 6

the miocene nullarbor limestone southern australia deposition on a vast subtropical epeiric platform abstract the early to middle miocene nullarbor limestone forms the vast karsted nullarbor plain in southern australia and may be the most extensive miocene carbonate deposit described to date these carbonates were deposited at southern paleolatitudes of 40 s and are interpreted to be subtropical to warm temperate in character because of the presence of certain genera of tropical coralline algae rhodoliths and articulated types large benthic foraminifera tropical molluscs zooxanthellate corals and micrite envelopes facies are dominated by skeletal grainstones and floatstones that accumulated in three interpreted paleoenvironments 1 seagrass banks upper photic zone 2 rhodolith pavements lower photic zone and 3 open seafloors lower photic to subphotic zone a decrease of tropical components from west to east across the platform implies that warm oceanic currents possibly related to a proto leeuwin current as well as a period of warm climate miocene climatic optimum resulted in subtropical deposition at southern latitudes the southern ocean extended inboard 450 km from the shelf edge during nullarbor limestone deposition but interpreted paleodepths did not extend much below the base of the photic zone a small slope angle 0 02 over a wide shelf 300 000 km2 implies deposition on an epeiric platform or epeiric ramp a miocene barrier reef was likely coeval with nullarbor limestone deposition therefore the inboard portion of the nullarbor limestone can be considered part of an extensive back reef lagoon system on a rimmed epeiric platform perhaps attaining a size similar to the modern great barrier reef system

gravity slide and resedimentation processes in a miocene carbonate ramp hyblean platcau southeastern sicily abstract more than twenty sharp based channel form structures occur in the miocene palazzolo formation carbonates within a distally steepened se sicilian miocene carbonate ramp contemporaneous biota indicate deposition in water depths of 70 150 m fully exposed structures commonly exceed one kilometre along palacostrike their bases are concordant with the host strata but these steepen to 15 in proximity of their margins internal bedding planes generally are concordant with the basal truncation surface the lithologies of the channel fills are similar to the host sediment there is little evidence that these structures are erosional since they contain neither breccias nor turbidites rather they are interpreted as the product of gravitational sliding involving thin detached sheets of consolidated ramp carbonates the resulting irregular topography was draped by redeposited fine grained carbonate sediments once healed and further oversteepened renewed gravity sliding occurred this resulted in a 250 m thick slide dominated succession in a zone 4 km wide located between the outer ramp apron comprised of coralline algal and foraminifera rich sediments and basin margin pelagic marls this phenomenon although unusual in shallow water settings is well known from modern continental slope environments sliding was probably triggered by seismicity in the region associated with two known mesozoic basement faults an alternative hypothesis involving pressure gradient build up along distally steepened ramp zones during storm surges is dismissed as a cause although this mechanism may have facilitated resedimentation of seafloor sediments over the slide zone

effects of local rock heterogeneities on the hydromechanics of fractured rocks using a digital image based technique a digital image based dib finite element approach is developed based on the numerical code rock failure process analysis rfpa to characterize micro scale rock heterogeneity and to understand the impact of micro scale rock heterogeneity on the macro scale hydromechanical response of rocks the dib technique incorporates small scale spatial variability of initial deformation modulus strength and permeability directly into a coupled hydromechanical model variability in young s modulus strength and permeability is applied by a property map defined from the pixel scale of a digital image in the rfpa mechanical deformation is followed including the accumulation of damage applied in individual elements which modifies modulus strength and permeability with the intensity of damage the rfpa simulates progressive failure in fractured rocks representing both the growth of existing fractures and the formation of new fractures without having to identify crack tips and their interaction explicitly in this dib simulation approach image voxels are used to give equivalent mechanical and flow properties these property maps are ported to the model capable of solving directly for the evolving deformation and fluid flow fields the model is validated through comparisons of the simulated results with phenomenological observations documented in previous studies the validated model is then applied to investigate the hydromechanical response of fractured rock characterized by digital image the model is able to reproduce the spatial evolution of damage in the sample the coalescence of existing cracks and the formation of new cracks

rapid mapping and analysing rock mass discontinuities with 3d terrestrial laser scanning in the underground excavation abstract whilst laser scanning techniques have been shown to facilitate rapid identification and analysis of rock mass characteristics relatively little research has been conducted for 3d laser scanning in underground spaces in the present study a semi automatic laser scanning method has been presented for non contact discontinuity identification and rock mass characterisation in a western australian underground gold mine the accuracy of the 3d laser scanning technique was compared with traditional window mapping with a strong correlation being noted the average dip dip direction discrepancy between the two methods was found to be 1 5 16 and attributed to the ability of 3d laser scanning to collect significant quantities of data when compared to traditional methods potential sources of error together with the influence of the scale effect were discussed with an optimum scanning resolution of 7 5 mm at 5 m being noted to provide a combination of significantly reduced collection and processing time and high levels of accuracy overall the present study demonstrated the potential of 3d laser scanning techniques to replace traditional methods with increased efficiency and accuracy in underground mines

anatomy of an upper silurian transgressive regressive cycle prince of wales island arctic canada the ludlovian pridolian cape storm douro and somerset island formations on eastern prince of wales island form a transgressive regressive succession that developed on the western flank of the active boothia horst sedimentation took place in a series of fault bounded subbasins that were at different times characterized by abundant microbolites rhodolites brachiopods and organisms that produced a diverse array of ichnofossils integration of paleoecological information from this succession provides a multifaceted paleoecological model which can be applied to similar lithologically monotonous successions throughout the world three main factors controlled the distribution of biota through the transgressive regressive cycle the most obvious factor was ever changing depositional settings caused by progressive rise and fall in sea level superimposed on this general pattern however was the influence of water circulation and the influx of detrital quartz from the boothia horst the microbolites and

significance of relic carbonate deposits along the central and southwestern margin of india for late quaternary environmental and sea level changes abstract environmental and sea level indicators were investigated using dredge samples from late quaternary carbonate deposits along the shelf break between goa and cape comorin india geomorphic features in the area were identified from sonar profiles and included isolated patch reefs with a relief of up to 10 m and linear reefs with reliefs between 2 and 15 m the main clast types recovered from these features include fragmented corals and carbonate nodules dominated by either encrusted foraminifera or coralline algae some of these clast types are clearly of shallow water origin fragments of reef forming poritid corals for example were collected off mangalore at depths of 110 105 m and dated between 11 520 and 12 610 14c years bp 13 42 14 77 ka nodules of similar age dominated by lithothamnium and capped by foraminiferal veneers were also collected at 90 m off cape comorin their altered algal tissues are consistent with formation in shallow water high energy conditions in contrast nodules recovered off kochi and mangalore goa are of deeper water origin younger in age 10 980 7350 14c years bp and are dominated by gypsina encrustations with volumetrically less algal encrustation they show cyclic succession of foraminiferal algal or foraminiferal algal coral laminations in which the algal species are typical of deeper waters the age and elevation of corals and shallow water nodules are both consistent with published glacio eustatic sea level curves in addition the alternate micro encrustations of foraminifera algae and encrusting corals could indicate changing conditions from nutrient rich and turbid to nutrient poor and clear water that may be attributable to seasonal variations in sediment flux caused by monsoons

stratigraphy of the upper cretaceous and lower tertiary strata in the tethyan himalayas of tibet tingri area china the 1500 m thick marine strata of the tethys himalaya of the zhepure mountain tingri tibet comprise the upper albian to eocene and represent the sedimentary development of the passive northern continental margin of the indian plate investigations of foraminifera have led to a detailed biozonation which is compared with the west tethyan record five stratigraphic units can be distinguished the gamba group upper albian lower santonian represents the development from a basin and slope to an outer shelf environment in the following zhepure shanbei formation lower santonian middle maastrichtian outer shelf deposits continue pebbles in the top layers point to beginning redeposition on a continental slope intensified redeposition continues within the zhepure shanpo formation middle maastrichtian lower paleocene the series is capped by sandstones of the jidula formation danian deposited from a seaward prograding delta plain the overall succession of these units represents a sea level high at the cenomanian turonian boundary followed from the turonian to danian by an overall shallowing upward megasequence this is followed by a final transgression regression cycle during the paleocene and eocene documented in the zhepure shan formation upper danian lutetian and by upper eocene continental deposits the section represents the narrowing and closure of the tethys as a result of the convergence between northward drifting india and eurasia the plate collision started in the lower maastrichtian and caused rapid changes in sedimentation patterns affected by tectonic subsidence and uplift stronger subsidence and deposition took place from the middle maastrichtian to the lower paleocene the final closure of remnant tethys in the tingri area took place in the lutetian

marine cretaceous paleogene biofacies and ichnofacies in southern tibet china and their sedimentary significance abstract the study of biofacies is of great significance not only for biostratigraphy but also for the interpretation of sedimentary environments and the reconstruction of paleogeography the areas of tuna gamba and tingri of southern tibet china were located in the north margin of the indian plate in the cretaceous and paleogene the marine cretaceous and paleogene biofacies there can be divided into four groups using the following criteria a the benthic biota and biogenic structures in the sediments b the paleoecology of the main fossils c the genesis of fossils the four groups are euxinic biofacies nektonic and planktic biofacies benthic biofacies and redeposited biofacies which include 24 main biofacies types like biofacies ichnofacies are important indicators of paleoenvironments the cretaceous paleogene trace fossils in the tuna and gamba areas are attributable to nereites zoophycos cruziana and skolithos ichnofacies nereites ichnofacies indicates an open marine basin environment zoophycos and cruziana ichnofacies indicate shelf margin and open sea shelf environments the skolithos ichnofacies reflects the environments of sand barrier deposited in the intertidal zone and the upper part of subtidal zone the zoophycos ichnofacies can further be subdivided into thalassinoides planolites and zoophycos chondrites subichnofacies which reflect aerobic and disaerobic conditions respectively the development of biofacies and ichnofacies in vertical profiles shows the sedimentary history from the early cretaceous to the paleogene in tuna gamba and tingri areas a regression occurred in tuna and gamba from the neocomian to the early paleocene the sedimentary environments went from euxinic basin and open marine basin shelf margin open sea margin platform slope platform margin open marine platform to the sand barriers deposited in the intertidal zone or the upper part of subtidal zone a transgression took place at the beginning of the middle paleocene the carbonate deposits formed in the open marine platform and open sea shelf environments overlay the sandstones of the jidula formation the termination of marine deposits in these areas began in the thanetian the sedimentary history in the tingri area differed from that in the tuna and gamba areas especially during middle maastrichtian to early paleocene times the sedimentary process in tingri during this period took place in the lower part the middle part of a fan and seaward prograding delta plains the marine deposition in the tingri area ended in lutetian later than in the tuna and gamba areas

re deposited rhodoliths in the middle miocene hemipelagic deposits of vitulano southern apennines italy coralline assemblage characterization and related trace fossils article i nfo an integrated analysis of rhodolith assemblages and associated trace fossils borings found in hemipelagic middle miocene orbulina marls vitulano area taburno camposauro area southern apennines italy has revealed that both the biodiversity of the constituent components and taphonomic signatures represent important aspects which allow a detailed palaeoecological and palaeoenvironmental interpretation on the basis of shape inner arrangement growth forms and taxonomic coralline algal composition two rhodolith growth stages were distinguished 1 nucleation and growth of the rhodoliths and 2 a final growth stage before burial nucleation is characterized by melobesioids and subordinately mastophoroids with rare sporolithaceans and lithophylloids the rhodolith growth main increase in size is represented by abundant melobesioids and rare to common mastophoroids very rare sporolithaceans are also present the final growth stage is dominated by melobesioids with rare mastophoroids and very rare sporolithaceans each rhodolith growth stage is characterized by a distinct suite of inner arrangement and growth form successions well diversified ichnocoenoeses gastrochaenolites trypanites meandropolydora and or caulostrepsis ento bia uniglobites micro borings related to bivalves sponges polychaetes barnacles algae fungi and bacteria are distinguished in the inner intermediate rhodolith growth stage while mainly algal fungal and bacterial micro borings are present in the outer final growth stage rhodolith growth stages and associated ichnocoenoeses indicate significant change in the depositional setting during the rhodolith growth in the vitulano area the middle miocene rhodolith assemblages formed in a shallow water open shelf carbonate platform were susceptible to exportation from their production area and then to sedimentation down to deeper water hemipelagic settings where the rhodoliths shortly kept growth and were finally buried such re deposition of unlithified or only weakly lithified i e rhodoliths and intraclasts shallow water carbonates into deeper water settings was likely favoured by storm generated offshore return currents rather than sediment gravity flows

hauterivian shallow marine calcareous biogenic mounds s e spain abstract hauterivian biogenic deposits from the prebetic northern margin near caudete albacete province southeastern spain are represented by low domed bodies less than 10 m thick surrounded by bioclastic sediments and capped by siliciclastics they consist of a coral stromatoporoid and microbial framework with cavities filled by mud rapidly lithified intermound bioclastics derived from the mound organic community reflect high energy conditions and shallow water settings mound growth and architecture were controlled by nutrient fluxes and internal light gradients comparisons with closely related structures from the palaeozoic and the recent show some similarities but also significant differences the example documented here also departs from other cretaceous occurrences

laffitteina from the maastrichtian paleocene shallow marine carbonate successions of the eastern pontides ne turkey biozonation and microfacies abstract microfacies and benthic foraminiferal assemblages from the maastrichtian paleocene shallow marine carbonate successions of the eastern pontides ne turkey are described and illustrated microfacies comprise fossiliferous intrasparites packed biomicrites biosparites rudistid biosparites gastropod biosparites miliolid biomicrites biosparites coralline algal biosparites and intrabiosparites dolomite horizons occur in the maastrichtian danian and lower upper paleocene transitions microfacies and microfossil content indicate deposition in shallow marine to lagoonal environments all within same sedimentary basin the shallow benthic foraminiferal zonal sbz scheme proposed for the tethyan paleogene is tested on eastern pontian material it cannot be applied to the paleocene in the eastern pontides due to the presence of the large number of endemic taxa and variable stratigraphic ranges of some benthic foraminifera various species of laffitteina have been used to produce a biozonation through the maastrichtian thanetian laffitteina marsicana farinacci and laffitteina oeztuerki inan occur in the lower and upper parts of the upper maastrichtian respectively laffitteina turcica inan occurs in the uppermost maastrichtian laffitteina bibensis marie appears in the lower paleocene danian laffitteina erki sirel in the upper paleocene selandian and they coexist from the selandian to the lower part of the thanetian

hooked and tubular coralline algae indicate seagrass beds associated to mediterranean messinian reefs poniente basin almeria se spain abstract abundant hooked and tubular crustose coralline algae cca record early messinian late miocene seagrass beds on the northern margin of the poniente basin in southeastern spain hooked and tubular shapes in cca result from their epiphytic growth over seagrass leaves and stems the lower messinian deposits consist of a thin retrograding subunit overlain by sigmoidal bed packages that prograded to the southwest at least 650 m from the basin margin seagrass deposits mainly occur as bivalve cca packstone to rudstone and cca floatstone seawards of a conglomerate facies belt in the retrograding subunit and downslope of coral reefs and serpulid packstone to rudstone in the prograding sigmoidal beds fragments of contorted foliose cca algal flakes some hooked or tubular are common components in the seagrass deposits they mainly belong to an unidentified species of mesophyllum like their present day counterparts the epiphytic cca grew attached to seagrass by the initial parts of their thalli and displayed unattached projections or open frameworks of contorted foliose plants in a few cases hooked cca occur attached to halimeda plates small benthic foraminiferal assemblages are further evidence of macrophyte vegetation hooked contorted foliose cca can be a helpful tool for the identification of ancient seagrass beds especially in mediterranean neogene and quaternary deposits in which foraminiferal taxa fully indicative of seagrass ecosystems are scarce

decline of the maastrichtian pelagic ecosystem based on planktic foraminifera assemblage change implication for the terminal cretaceous faunal crisis an outer shelf upper slope tropical tethyan pelagic environment existed over southern israel during maastrichtian time planktic foraminifera in the 63 and 149 m size fractions from four sections in this area were studied quantitatively for a high resolution ecostratigraphic analysis of the pre cretaceous tertiary k t paleoenvironment during the maastrichtian 41 of the planktic foraminifera species became extinct mostly keeled globotruncanidae which also became quantitatively reduced near the end of the maastrichtian from as much as 35 to only 5 of the planktic foraminifera population evolutionary replacement of extinct species by new forms nearly ceased in that interval two major opportunistic blooms of guembelitria took place associated with reduced abundances of keeled forms and the dominant species heterohelix globulosa the first bloom occurred within the upper gansserina gansseri to lower abathomphalus mayaroensis zones and the second within the plummerita hantkeninoides zone the extinctions concomitant changes in faunal dominance and opportunist blooms indicate that the pelagic ecosystem in the negev area experienced multiple stresses during the maastrichtian the planktic foraminiferal assemblages were taxonomically impoverished and in decline prior to the k t boundary crisis

microbial domes and megaoncoids in miocene reefs in the mahakam delta in east kalimantan indonesia abstract coral patch reefs in the miocene mahakam delta in east kalimantan borneo indonesia developed in shallow marine turbid waters these reefs grew in delta front to prodelta environments under fluctuating siliciclastic input langhian patch reefs are well exposed in limestone quarries of the air putih area near the city of samarinda and include two different types of microbial carbonates in two sections 2 km apart in the northern section microbialites occur as low relief domes up to 2 m wide and 0 5 m high the domes show internal lamination and coralline algae and encrusting foraminifers interlayered with microbial micrite they developed around large coral fragments at the transition from reef deposits to fine grained siliciclastics microbialites in the southern section formed decimetre to metre scale nodules here termed megaoncoids around nuclei of large coral fragments microbial micrite with laminated to digitate fabrics intergrew with coralline algae and encrusting foraminifers to form the thick covers of megaoncoids small nodules were bound together in larger ones which are usually strongly asymmetric internally megaoncoids accumulated in a carbonate breccia laterally changing into coral boundstones in both sections microbialites grew on the flanks of shallow water low relief patch reefs in poorly illuminated low energy conditions flat domed microbialites formed on a nearly horizontal stable seafloor seawards of the patch reef the megaoncoids in the southern section formed as a result of downslope displacement of coral fragments coated by microbialite coralline algal encrusting foraminifer crusts the slope of the patch reef s flank favoured the falling and rolling of encrusted corals with the continued growth of microbial crusts on all sides of nodules in contrast to quaternary and recent occurrences of microbialites in indo pacific and caribbean reefs the samarinda microbialites are not components of the reef framework nor formed in deep water instead they developed in shallow turbid waters of the miocene mahakam delta in periods of arrested siliciclastic input

a semi automated methodology for discontinuity trace detection in digital images of rock mass exposures abstract the in situ measurement of discontinuity geometry at rock mass exposures is a slow process it can be hazardous and often a large proportion of the exposure is inaccessible photogrammetry is a safer method with which to measure discontinuity geometry and by removing the issues of inaccessibility it provides greater access to the exposure the use of digital images rather than customary analogue photographic images for photogrammetry retains these benefits while offering the prospect of an automated and hence fast method of discontinuity detection and discontinuity geometry analysis this paper presents a methodology for semi automated discontinuity trace detection in greyscale digital images of rock mass exposures the methodology detects discontinuity traces as individual objects which is a necessary precursor to automated discontinuity geometry analysis the methodology initially considers a rock mass exposure digital image as a discrete surface the elevation of which is given by pixel brightness levels by doing so a discontinuity trace can be likened to a topographic ravine and therefore some pixels within a discontinuity trace can be found by locating the so called ravine pixels a series of digital image processing techniques are then applied to group and transform these ravine pixels into linear structures that are more suited to computer decision making and this results in what we call ravine line segments a novel method is presented that links these ravine line segments together to achieve discontinuity trace detection the method considers three criteria during the linking process to help ensure acceptable discontinuity detection these criteria involve the nature of the image search the angles used to control the shape of a discontinuity trace and the brightness of the pixels in the rock mass exposure image case studies show the discontinuity trace maps that result when the methodology is applied to several rock mass exposure images and a comparison is made between a discontinuity trace map produced by the methodology and several drawn by hand

reef building and carbonate production modes in the west central tethys during the cenozoic abstract changing components rock textures lithofacies platform types and architecture throughout time are unique characteristics of carbonate rocks characterizing these attributes has been approached by 1 building reference models for specific phanerozoic intervals 2 recognizing the climatic impact in modulating carbonate production and 3 analyzing the influence of changing bio geochemical conditions the reference model approach is mostly based on biological evolution the climatic impact approach emphasizes temperature and the bio geochemical approach considers the changes in mg ca ratios and ca concentrations in the oceans to date however an analysis integrating all of these factors is still missing the analysis presented here includes all these factors but also co 2 which is fundamental for both photosynthesis and caco 3 precipitation here we analyze the waxing and waning of cenozoic reef limestones from the central tethys region through several steps 1 on the basis of rock volume rock textures associated sediments and light dependent skeletal components as records of light penetration and wave energy depth 2 on global environmental conditions 13 c 18 o p co 2 temperature and 3 on the basis of functionality nutritional requirements and available resources through the cenozoic water motion whether induced by surface or internal waves or by currents increased as the thermal gradients strengthened both with depth and with latitude active water motion is essential for plankton catchers such as corals but less so for many larger benthic foraminifers lbf pycnoclines in the meso oligophotic zone would then favor the benthic plankton catchers such as corals but would be detrimental for many lbf warm temperatures favored lbf the eocene lbf families predominated during lowering of atmospheric p co 2 by using respiratory co 2 to enhance the symbiont production of photosynthates under oligotrophic conditions and limited turbulence whereas the miocene families had to adapt to a progressive increase in turbulence the eurythermal coralline red algae however became preponderant producers in the mesophotic zone during times when the 13 c was relatively high this explains two apparent paradoxes 1 corals thrive best when the earth s high latitudes cool and 2 the dominance of corals and lbf is inversely correlated despite they both require tropical conditions and have similar trophic strategies mixotrophy

palaeoenvironment and palaeogeography of miocene marls from southeast sicily and the maltese islands abstract tortonian marls and clays are extensively developed in southeast sicily macrofaunas are sparsely distributed in these strata except for a new section at musenna hill in the vittoria scoglitti area this section together with two other coastal sequences of about the same age are described for the first time their abundant faunas are recorded ecological requirements for these faunas are considered and some attempt is made to place them into the known sicilian miocene stratigraphy the musenna hill section shows a particularly close relationship to the upper part of the miocene blue clay formation of the maltese islands both from the viewpoint of sediment and macrofauna the maltese faunas are recorded in detail for the first time and ecological and palaeogeographical information is considered an attempt at an overall regional palaeoenvironmental reconstruction is made for the maltese and southeast sicilian parts of the central mediterranean for tortonian times

a geometry and texture based automatic discontinuity trace extraction method for rock mass point cloud abstract this paper presents an automatic extraction method for discontinuity trace mapping from 3d point cloud of natural rocky slopes unlike the methods based only on geometrical information the proposed method also takes textural information into account by using the texture mapping method a texture map and a normal map are generated from the point cloud which contain textural and geometrical information respectively then the rolling guidance filter and a multi scale edge chain detector are applied to the image to extract discontinuity traces finally edge chains in the image were projected back to the 3d coordinate system through the previously established texture map the proposed method is applied to three case studies each representing a different situation the results show that the proposed discontinuity trace extraction method is automatic robust extensible and performs better than geometry based methods for smooth rock surfaces along which the curvature changes are not apparent the proposed method could be used as a supplement to traditional contact discontinuity trace mapping methods

environmental controls on marine ecosystem recovery following mass extinctions with an example from the early triassic abstract the recovery of marine ecosystems following a mass extinction event involves an extended interval of increasing biotic diversity and ecosystem complexity the pace of recovery may be controlled by intrinsic ecosystem or extrinsic environmental factors here we present an analysis of changes in marine conditions following the end permian mass extinction with the objective of evaluating the role of environmental factors in the protracted 5 myr long recovery of marine ecosystems during the early triassic specifically our study examines changes in weathering productivity and redox proxies in three sections in south china chaohu daxiakou and zuodeng and one in northern india mud our results reveal 1 recurrent environmental perturbations during the early triassic 2 a general pattern of high terrestrial weathering rates and more intensely reducing marine redox conditions during the early griesbachian late griesbachian mid smithian and more weakly the mid spathian 3 increases in marine productivity during the aforementioned intervals except for the early griesbachian and 4 stronger and more temporally discrete intervals of environmental change in deepwater sections chaohu and daxiakou relative to shallow and intermediate sections zuodeng and mud our analysis reveals a close relationship between episodes of marine environmental deterioration and a slowing or reversal of ecosystem recovery based on metrics of biodiversity within community alpha diversity infaunal burrowing and ecosystem tiering we infer that the pattern and pace of marine ecosystem recovery was strongly modulated by recurrent environmental perturbations during the early triassic these perturbations were associated with elevated weathering and productivity fluxes implying that nutrient and energy flows were key influences on recovery more regular secular variation in deepwater relative to shallow water environmental conditions implies that perturbations originated at depth i e within the oceanic thermocline and influenced the ocean surface layer irregularly finally we compared patterns of environmental disturbance and ecosystem recovery following the other four big five phanerozoic mass extinctions to evaluate whether commonalities exist in general the pace of ecosystem recovery depends on the degree of stability of the post crisis marine environment

late cretaceous to late eocene palaeogeographic evolution of southwest europe abstract a synthesis of personal research concerning the peri pyrenean region and previously published data is presented as a series of palaeogeographic reconstructions subsequent to the progressive regression at the end of the cretaceous the sea invaded three times parts of the earlier senonian marine domain on both sides of the eastern palaeo pyrenees pre cuisian climatic rewarming combined with cuisian continental epeirogenic deformations resulted in major biogeographic modifications during the cuisian local tectonics forced the sea from the northern pyrenean basin whereas in the southern pyrenean basin the sea retreated much later as a consequence of the pyrenean tectonic phase however the pyrenean tectogenesis seems to have affected a much larger region including the alps shoreline migrations are compared and related to the geodynamic behaviour of the meridional and septentrional european provinces in order to distinguish between tectonic and eustatic causes

the miller volcanic spark discharge experiment miller9s 1950s experiments used besides the apparatus known in textbooks one that generated a hot water mist in the spark flask simulating a water vapor rich volcanic eruption we found the original extracts of this experiment in miller9s material and reanalyzed them the volcanic apparatus produced a wider variety of amino acids than the classic one release of reduced gases in volcanic eruptions accompanied by lightning could have been common on the early earth prebotic compounds synthesized in these environments could have locally accumulated where they could have undergone further processing

late oligocene to pliocene extension in the maltese islands and implications for geodynamics of the pantelleria rift and pelagian platform

crustose coralline algae from the flower garden banks northwestern gulf of mexico controls on distribution and growth morphology abstract the east and west flower garden banks in the northwestern gulf of mexico represent the northernmost tropical coral reefs and caribbean coralline algal flora on the north american continental shelf coralline algae are the dominant framework builders and sediment contributors below 50 m on the banks on the basis of growth form and taxonomic composition coralline algae on the flower garden banks can be divided into four overlapping depth zones upper coral reefs 20 30 m madracis algal ridges 30 40 m algal nodule zone 45 80 m and deep algal reefs 50 90 m corallines on the upper coral reefs are dominated by hydrolithon lithophyllum and porolithon their growth form as thick laterally restricted crusts and knobs results from intensive grazing by parrotfish and urchins grazing is diminished on the madracis algal ridges below the upper reefs and corallines grow here as laterally extensive plates binding coral rubble dominant corallines on the ridges are lithophyllum paragoniolithon and tenarea algal nodules rhodoliths o the deeper bank slopes are the most widespread algal growth form on the flower garden banks on the basis of shape internal structure and composition rhodoliths are divided into an upper zone where they have a spherical shape with concentric laminae and a lower zone discoidal shape with irregular laminae diminishing current velocity with increasing depth controls nodule morphology the red alga peyssonnelia and the foraminifer gypsina are two non coralline components that contribute substantially to nodule growth reduced current velocity in the lower nodule zone enables corallines and peyssonnelia to develop laterally extensive pavements and 1 2 m high algal reefs taxonomic composition high framework porosity and irregular internal growth morphology f the deep algal reefs distinguish these structures from shallow algal ridges described elsewhere the 90 m isobath at the flower garden banks approximates the upward limit of a turbid nepheloid layer composed of continually resuspended sediment reefal structures within this water layer are dead and are now covered by fine sediment

short paper a standardized model for tethyan tertiary carbonate ramps low latitude carbonates in massive and clinoform bedded sheets termed ramps occur throughout the tertiary tethyan realm and are characterized by recurring biofacies usually including large foraminifera rhodolithic algae coralgal patch reef and gastropod dominated sequences all can be interpreted broadly within a standardized tertiary carbonate ramp model biota can be used to define precise palaeobathymetric zones which have a predictive utility in palaeoenvironmental modelling especially where data are limited the carbonate ramp model of earlier authors has been elaborated by read 1982 and ramp formation occurs mostly in passive margin and extensional tectonic settings ramps are characterized by slope gradients of less than 1 degree and once established are conservative to change much use has been made of the ramp model for palaeozoic and mesozoic lithofacies modelling in contrast published work on cenozoic ramps is limited however tethyan ramps are particularly widespread and extend tens to hundreds of kilometres along strike and occupy tens of kilometres of slope many studies have dealt with cenozoic ramp associations and sequences e g pedley 1983 reiss hottinger 1984 purser 1973 and have demonstrated the diversity of biotal and sediment detail but without ascribing them to a ramp model biota were quick to adapt to the tertiary environments left vacant after the k t boundary extinction events new genera of foraminifera mollusca bryozoa and echinoder mata rapidly replaced the extinct forms in bursts of innovative opportunism codiacean algae rhodophyta and marine angiosperms were equally adaptive colonizers of the carbonate platforms novel biofacies associations were derived from

paleoecology and dynamics of coralline dominated facies during a pleistocene transgressive regressive cycle capo colonna marine terrace southern italy abstract the upper pleistocene deposits of capo colonna marine terrace calabria southern italy contain a volumetrically important record of red algal facies developed during a transgressive regressive cycle well expressed along a nearshore offshore transect this setting presents an ideal opportunity for the acquisition and interpretation of paleoecological information on coralline dominated deposits and their response to relative sea level changes the capo colonna deposits include rigid build ups rhodolith accumulations and a maerl bed the build ups identified as a fossil example of the present day mediterranean coralligenous are primarily formed by mesophyllum alternans and subordinately by lithophyllum stictaeformae titanoderma pustulatum and lithothamnion sp rarely alternating with encrusting bryozoans fruticose praline rhodoliths occur in a packstone bed up to 160 cm thick 2 to 5 cm in size and composed of lithothamnion sp mesophyllum sp and rare t pustulatum the maerl bed is about 60 cm thick and laterally continuous for several tens of meters and consists of interlocked unattached red algal branches of the species lithothamnion corallioides phymatolithon sp lithophyllum sp and lithothamnion sp the lateral distribution along the shelf profile of different red algal facies was influenced by transgressive regressive trends while praline rhodoliths and the maerl bed developed on mobile substrates mostly during the early highstand respectively at intermediate and distal shelf sectors the mesophyllum dominated coralligenous build ups continued to grow for most of the regressive phase progressively occupying all the preserved paleoshelf profile during sea level fall and resulting in a characteristic ecological vertical succession of crustose algae facies in the distal segment of the transect differences in substrate types determined variability in the coralligenous morphologies with dome to mushroom shapes starting from discontinuous blocks of a basal conglomerate and we elongated platforms developing from a hardground and from rhodolith beds eventually the development of red algal deposits became in itself the dominant control on substrate type the red algae rich deposits of capo colonna marine terrace not only suggest a relationship between available substrate and geomorphological expression of the coralligenous build ups but also provide a framework for the paleoecological interpretation of other neogene and quaternary rhodalgal deposits from the mediterranean region

sedimentology and palaeoecology of a miocene coralline algal biostrome from the maltese islands abstract a large coralline algal biostrome 20 km 5 km 16 m thick is well exposed in western malta and eastern gozo the biostrome is composed of limestones largely constructed by in situ coralline algae or transported algal debris some sediments are dominated by rhodoliths and others by crustose coralline frameworks six facies are distinguished crustose algal marl crustose algal wackestone rhodolith pavement algal branch packstone crustose pavement and algal crust packstone each facies is characterised by different rhodolith morphologies and coralline crusts which are constructed mainly bymesophyllum commune the coralline morphogenesis is related to the palaeoenvironmental conditions the biostrome is thought to have developed from a series of relic sand ridges to form a low relief platform of moderate depths containing a mosaic of sedimentary facies the sequence is affected by growth faulting which divides the biostrome into eight units

paleoecology of the cretaceous tertiary mass extinction in planktonic foraminifera abstract paleobiogeographic patterns of the cretaceous tertiary k t mass extinction in planktonic foraminifera in tunisia spanning environments from open marine upper bathyal to shelf and shallow marginal settings indicate a surprisingly selective and environmentally mediated mass extinction this selectivity is apparent in all of the environmental proxies used to evaluate the mass extinction including species richness ecological generalists ecological specialists surface and subsurface dwellers whether based on the number of species or the relative percent abundances of species the following conclusions can be reached for shallow to deep environments about three quarters of the species disappeared at or near the k t boundary and only ecological generalists able to tolerate wide variations in temperature nutrients salinity and oxygen survived among the ecological generalists heterohelicids guembelitrids hedbergellids and globigerinellids only surface dwellers survived ecological generalists which largely consisted of two morphogroups of opportunistic biserial and triserial species also suffered selectively biserials thrived during the latest maastrichtian in well stratified open marine settings and dramatically declined in relative abundances in the early danian triserials thrived only in shallow marginal marine environments or similarly stressed ecosystems during the latest maastrichtian but dominated both open marine and restricted marginal settings in the early danian this highly selective mass extinction pattern reflects dramatic changes in temperature salinity oxygen and nutrients across the k t boundary in the low latitude tethys ocean which appear to be the result of both long term environmental changes e g climate sea level volcanism and short term effects bolide impact

semi automatic extraction of rock mass structural data from high resolution lidar point clouds abstract in this paper a matlab tool called diana discontinuity analysis for the 2d and 3d geo structural analysis of rock mass discontinuities on high resolution laser scanning data is presented the proposed approach is able to semi automatically retrieve some relevant rock mass parameters namely orientation number of sets spacing frequency and derived rqd persistence block size and scale dependent roughness by analyzing high resolution point clouds acquired from terrestrial or aerial laser scanners in addition with a specific diana option called filterveg we are able to remove vegetation or other disturbing objects from the point cloud which is one of the main problems in lidar data processing some examples of the proposed method have demonstrated its ability to investigate rock masses characterized by irregular block shapes and suggest applications in the field of engineering geology and emergency management when it is often advisable to minimize survey time in dangerous environments and in the same time it is necessary to gather all the required information as fast as possible

high stress late maastrichtian paleoenvironment inference from planktonic foraminifera in tunisia high resolution v5 10 kyr planktonic foraminiferal analysis at elles tunisia reveals major changes in the structure of the tethyan marine ecosystem during the upper maastrichtian during the first 1 5 myr of the late maastrichtian 68 3 66 8 ma relatively stable environmental conditions and cool temperatures are indicated by diverse planktonic foraminiferal populations with abundant intermediate and surface dwellers a progressive cooling trend between v66 8 65 45 ma resulted in the decline of globotruncanid species intermediate dwellers this group experienced a further decline at the climax of a rapid warm event about 300 kyr before the k t boundary at the same time relative abundances of long ranging dominant species fluctuated considerably reflecting the high stress environmental conditions times of critical high stress environments during the late maastrichtian and particularly at the k t boundary are indicated by low species diversity and blooms of the opportunistic genus guembelitria at warm cool transition intervals during the last 100 kyr of the maastrichtian rapid cooling is associated with accelerated species extinctions followed by the extinction of all tropical and subtropical species at the k t boundary fl 2002 elsevier science b v all rights reserved

diversity growth forms and taphonomy key factors controlling the fabric of coralline algae dominated shelf carbonates the fabric of biogenic carbonate sediments can be differentiated 1 with respect to diversity of constituent components 2 using features pertaining to their growth forms and 3 upon consideration of taphonomic aspects these not only determine limestone fabrics but also form the basis for facies differentiation and palaeoecological interpre tation this study is based on coralline algae dominated lower oligocene shelf carbonates from northern slovenia from which seven facies nummulitic bivalve foraminiferal coralline algal coralline algal coralline algal coral coral and grainstone are differentiated the role of diversity growth forms and taphonomy of coralline algae in each facies is discussed nine species from seven genera of coralline algae including geniculates and non geniculates were recognized numerous different growth forms ranging from crusts protuberances lamel lae to arborescent types are present a wide range of taphonomic features including dis articulation encrustation fragmentation and abrasion can be observed the determination of diversity is dependent on taxonomic identification using preserved diagnostic characters relevant to palaeontological and botanical systematics growth form determination in thin section is influenced by orientation and sectioning effects the taphonomy of red algae is highly dependent on initial growth form and the specific environ ment in which they are found a number of taphonomic processes described in

the ecors deep reflection seismic survey across the pyrenees the pyrenees are an alpine age mountain belt located on the boundary between the iberian and european plates using the same geological and geophysical data earth scientists studying the structure of the pyrenees during the past ten years have not reached a consensus here we report the first results from a nearly continuous 255 km long reflection seismic survey across the pyrenean chain this first deep reflection profile of an entire erogenic belt will help to constrain possible models for the structure and formation of the pyrenean chain

high resolution planktonic foraminiferal analysis from the cretaceous tertiary boundary at ain settara tunisia evidence of an extended mass extinction the ain settara section located in the kalaat senan area of north central tunisia spans the cretaceous tertiary k t boundary which is characterized by a red layer and a thin non bioturbated boundary clay sediment accumulation across the k t boundary at ain settara was probably interrupted by three short hiatuses and or condensed sedimentation the first hiatus occurs at the top of the cf1 zone the second hiatus condensation occurred just below the boundary clay and the third hiatus at the p0 p1a boundary in the earliest danian these hiatuses are marked by weak unconformities bioturbation and sudden disappearances appearances of species which are known to disappear evolve sequentially in continuous sections quantitative high resolution planktonic foraminiferal analysis across zones cf1 upper p0 and p1a 1 reveals an extended and selective mass extinction all 41 of the species which disappeared at or below the k t boundary are rare to very rare and primarily ecologically specialized keeled deeper dwelling tropical subtropical forms globotruncana globotruncanita gublerina planoglobulina rosita contusotruncana racemiguembelina their combined relative abundance varies between 10 and 15 of the total population at the end of the maastrichtian the k t crisis thus appears more catastrophic when viewed in tropical subtropical assemblages and based on analysis of larger species 200 m which preferentially includes the more specialized forms though in fact the k t mass extinction actually involved a relatively small part of the foraminiferal population in terms of relative abundance the pattern of extinction and changes in dominant population at ain settara appear to be very similar to the planktonic foraminiferal turnover of the other north central tunisian sections el kef elles the selective mass extinction pattern suggests that the catastrophic effects of the bolide impact superimposed those related to long term environmental changes such as variations in temperature sea level and associated water mass changes