late quaternary slip rates on the acireale piedimonte normal faults and tectonic origin of mt etna sicily abstract mt etna is located along the east coast of sicily near the boundary between the continental crust of the hyblean plateau and the mesozoic oceanic crust of the ionian basin the main active faults near mt etna cut the base of its eastern flank forming a 30 km long system of nne and nnw trending ene chelon fault segments the acireale piedimonte system showing dip slip and oblique right lateral motion most segments are associated with shallow depth seismicity and all have late pleistocene to holocene vertical slip rates ranging between 1 and 2 mm yr typical of major active normal faults worldwide eruptive fissures arranged in nne to ne trending zones cut the highest slopes of the volcano on the footwall of the normal fault system structural analysis suggests that current motions along both the active faults and eruptive fissures are kinematically compatible and simply linked with ongoing wnw ese directed regional extension such extension characterizes at a greater scale the active tectonics of southern italy where all large shallow historical earthquakes have remained confined within a narrow normal fault belt or rift zone stretching from the northern calabrian arc to southeastern sicily the southernmost west dipping faults of that rift zone in calabria aspromonte cut across the calabro peloritan thrust belt to join the mostly east dipping acireale piedimonte faults along the western boundary of ionian oceanic lithosphere which continues southwards as the malta escarpment we thus relate magmatism at etna to dilational strain on the footwall of an east facing crustal scale normal fault at the bend where the siculo calabrian rift zone veers 60 eastwards as it begins to cross the calabrian arc leaving the east facing margin of the ionian sea to catch up with the west facing margin of the tyrrhenian sea farther north

latitudinal temperature gradient during the cretaceous upper campanian middle maastrichtian y18o record of continental vertebrates latitudinal variations in model biogenic apatite d18o values were calculated using fractionation equations of vertebrates and weighted rainfall y18o values along with mean annual air temperatures provided by iaea wmo meteorological stations the reference equation obtained was used to compute a continental temperature gradient for the late campanian middle maastrichtian interval by using published and new d18o values of phosphate from vertebrates samples are mainly tooth enamel from crocodilians and dinosaurs that lived at paleolatitudes ranging from 83 4 n alaska to 32 3 s madagascar the temperature gradient was less steep 0 4 0 1 c latitude than the present day one 0 6 c latitude with temperatures that decreased from about 30 c near the equator to about 5 c at the poles above 30 of paleolatitude air temperatures were higher than at present the validity of these results is discussed by comparison with climatic criteria inferred from paleontological paleobotanical and sedimentological data the latitudinal distribution of oxygen isotope compositions of continental vertebrates is potentially a powerful tool for quantifying mesozoic terrestrial climates

isotopic composition of recent shark teeth as a proxy for environmental conditions abstract the o c and sr isotope compositions of teeth from ten species belonging to five families and three orders of sharks were measured to determine the influence of habitat diet and possible species specific fractionation effects on the isotopic composition of biogenic phosphate from fish the sharks were recently caught in subtropical waters off the kwazulu natal kzn coast of south africa as well as from cold waters in prince william sound pws alaska and victor bay vb nunavut canada 18 o values of tooth phosphate 18 o p range from 20 9 to 23 5 for the kzn sharks for most species the range in measured 18 o p values is about 0 6 but it may be as high as 1 1 for different teeth from a single shark dentine and enameloid within individual teeth have no apparent differences in 18 o p values the 18 o p values of the kzn shark teeth reflect the typical habitat of the studied species primarily the thermal structure of the water column off kzn at depths between 20 and 280 m the 18 o p values of teeth from different greenland sharks from vb and pacific sleeper sharks from pws are very homogeneous averaging 25 8 and 24 7 respectively these values appear to be in equilibrium with deep 500 m ocean waters in each case at temperatures of about 0 3 c or less there is little discernable evidence for species specific fractionation effects for the oxygen isotope composition of phosphate in the studied marine fish the oxygen isotope composition of carbonate in apatite averages about 9 1 higher than corresponding 18 o p values in agreement with equilibrium fractionation between carbonate and phosphate but with a large variance 1 1 5 18 o c values also vary by up to 1 between enameloid and dentine within single teeth but in a non systematic way differences in 13 c values between carbonate in enameloid and dentine is also large up to 8 but the 13 c values vary systematically enameloid is always enriched in 13 c compared to dentine and the 13 c content increases with developmental stage of the teeth 13 c values measured for enameloid 1 6 to 4 8 appear to approach equilibrium with dissolved inorganic carbon in seawater in contrast 13 c values for dentine range from 6 4 to 2 3 for kzn sharks and 9 0 to 10 8 for the cold water sleeper sharks and are compatible with a predominantly dietary carbon source the 87 sr 86 sr ratios of teeth from kzn sharks as well as those from pws and vb are uniform averaging 0 709167 sr content varies from 1270 to 2100 ppm a range that is similar to that in well preserved fossilized teeth seawater sr is thus clearly incorporated in vivo concentrations of sm and nd are in the ppb range and contrast the ppm range in fossilized teeth indicating a postmortem incorporation of rare earth elements in apatite of the teeth

the valle del bove mount etna its origin and relation to the stratigraphy and structure of the volcano abstract the valle del bove is a major horseshoe shaped depression some 5 km in diameter and over 1000 m deep carved into the eastern flank of mount etna volcano the origin of the valle del bove has been a subject of debate for over a century but recent models relate it to the collapse of the ancient trifoglietto ii centre of etna either by caldera collapse or phreatomagmatic explosive activity careful morphological analysis shows the valle del bove to have formed after the post trifoglietto ii ellittico and leone centres and therefore to be considerably younger than the trifoglietto ii centre it has also been argued that the pyroclastic deposits that occur on the flanks of the volcano in close spatial relationship with the valle del bove were produced by the same event these pyroclastics are divided on the basis of age and composition into two groups the upper and lower tephra deposits the stratigraphy petrology and radiocarbon date of the lower tephra deposits indicate a trifoglietto ii age at least 20 000 years before the formation of the valle del bove the upper tephra deposits have a strong phreatomagmatic character and are closest in age to the valle del bove there is no evidence however to link them with its formation morphological study shows the valle del bove to consist of a series of coalescing scallops indicative of formation by landsliding the material removed by slope failure and subsequent fluvial transport followed a valley to the coast where it forms a fan shaped accumulation the chiancone consisting of volcaniclastics of fluvial and mudflow origin it is argued that the valle del bove did not result from simple caldera collapse but formed from a series of collapses caused by gravitational slope failure the chiancone is considered to be the product of this collapse

testing the cretaceous greenhouse hypothesis using glassy foraminiferal calcite from the core of the turonian tropics on demerara rise glassy turonian foraminifera preserved in clay rich sediments from the western tropical atlantic yield the warmest equivalent 18o sea surface temperatures ssts yet reported for the entire cretaceous cenozoic we estimate turonian ssts that were at least as warm as conservative mean 30 c to significantly warmer warm mean 33 c than those in the region today however if independent evidence for high middle cretaceous pco2 is reliable and resulted in greater isotopic fractionation between seawater and calcite because of lower sea surface ph our conservative and warm sst estimates would be even higher 32 and 36 c respectively our new tropical ssts help reconcile geologic data with the predictions of general circulation models that incorporate high cretaceous pco2 and lend support to the hypothesis of a cretaceous greenhouse our data also strengthen the case for a turonian age for the cretaceous thermal maximum and highlight a 20 40 m y mismatch between peak cretaceous cenozoic global warmth and peak inferred tectonic co2 production we infer that this mismatch is either an artifact of a hidden turonian pulse in global ocean crust cycling or real evidence of the influence of some other factor on atmospheric co2 and or ssts a hidden pulse in crust cycling would explain the timing of peak cretaceous cenozoic sea level also turonian but other factors are needed to explain high frequency 10 100 k y instability in middle cretaceous ssts reported elsewhere

new field evidence for an exposure of the appalachian decollement at the east end of the pine mountain terrane georgia detailed field mapping at the east end of the pine mountain terrane in central georgia indicates that the box ankle fault is an 4 km thick ductile shear zone separating grenvillian basement of laurentian affinity in the footwall from allochthonous accreted terranes in the hanging wall fabric data from the box ankle fault indicate that it is a gently southeast dipping northwest vergent thrust fault recently discovered structural relations together with geochronological data indicate that the box ankle fault is of late paleozoic age we argue that the box ankle fault is a surface exposure of the appalachian decollement the east end of the pine mountain terrane may be the only place in the entire orogen where this fundamentally important structure is exposed for study

late cretaceous early tertiary palaeoclimates of northern high latitudes a quantitative view analyses of plant community structure vegetational and leaf physiognomy and growth rings and vascular systems in wood provide qualitative and quantitative data that can be combined to define non marine palaeoclimatic parameters with better resolution than is available from other principally sedimentological methods application of these techniques to cenomanian through paleocene floras from high palaeolatitudes 75 85 n indicates a polar light regime similar to that of the present plant data suggests cenomanian sea level mean annual air temperatures mats of 10 c and mats of 13 c 5 c and 6 7 c in the coniacian maastrichtian and paleocene respectively evapotranspirational stresses at sea level were low and precipitation was in most part uniform throughout the growing season in the cenomanian with possible seasonal drying occurring by the maastrichtian maastrichtian winter freezing was likely but periglacial conditions did not exist at sea level permanent ice was likely above 1700 m at 75 n in the cenomanian and above 1000 m at 85 n in the maastrichtian these near polar data provide critical constraints on global models of late cretaceous to early tertiary climates

middle late cretaceous climate of the southern high latitudes stable isotopic evidence for minimal equator to pole thermal gradients a detailed 18 o and 13 c stratigraphy has been generated from analysis of well preserved albian early maastrichtian foraminifera from deep sea drilling project dsdp sites 511 and 327 falkland plateau 58 s 62 s paleolatitude in the southern south atlantic and cenomanian and coniacian santonian foraminifera from dsdp site 258 naturaliste plateau 58 s paleolatitude in the southern indian ocean these results when combined with previously published maastrichtian stable isotope data from ocean drilling program odp site 690 weddell sea 65 s paleolatitude provide new insight into the climatic and oceanographic history of the southern high latitudes during middle late cretaceous time the planktonic foraminifer 18 o curves reveal a gradual warming of surface waters from the albian through the cenomanian followed by extremely warm surface waters from the turonian through the early campanian long term cooling of surface waters began in the late early campanian and continued through the end of the maastrichtian the benthic foraminifer 18 o record generally parallels changes in the oxygen isotopic curves defined by shallow dwelling planktonic foraminifera the vertical oxygen and carbon isotopic gradients were relatively low during the albian cenomanian high from the turonian early campanian and then low during the late campanian and maastrichtian foraminiferal oxygen isotopic data from published sources and this study are averaged for each site corrected for latitudinal changes in salinity based on modern day surface water values and plotted versus paleolatitude for the late albian coniacian santonian and late maastrichtian differences between lowand high latitude surface water paleotemperatures are estimated at 14 c during the late albian and late maastrichtian but the coniacian santonian reconstruction reveals only a 0 4 c latitudinal temperature gradient uncertainty regarding cretaceous salinity gradients and possible diagenetic alteration of 18 o values introduce error into our estimates of paleolatitudinal thermal gradients however apparent low equator to pole temperature differences could indicate much higher poleward heat transport than at present

fish tooth δ18o revising late cretaceous meridional upper ocean water temperature gradients the oxygen isotope composition of fossil fi sh teeth a paleo upper ocean temperature proxy exceptionally resistant to diagenetic alteration provides new insight on the evolution of the low to middlelatitude thermal gradient between the middle cretaceous climatic optimum and the cooler latest cretaceous period the new middle cretaceous low to middle latitude thermal gradient agrees with that previously inferred from planktonic foraminifera 18o recovered from deep sea drilling project and ocean drilling program drilling sites although the isotopic temperatures derived from 18o of fish teeth are uniformly higher by 3 4 c in contrast our new latest cretaceous thermal gradient is markedly steeper than those previously published for this period fish tooth 18o data demonstrate that low to middle latitude thermal gradients of the middle cretaceous climatic optimum and of the cooler latest cretaceous are similar to the modern one despite a cooling of 7 c between the two periods our new results imply that no drastic changes in meridional heat transport are required to explain the late cretaceous climate based on climate models such a cooling without any change in the low to middle latitude thermal gradient supports an atmospheric co2 decrease as the primary driver of the climatic evolution recorded during the late cretaceous

oxygen isotope variations in phosphate of biogenic apatites i fish bone apatite rechecking the rules of the game abstract the major advantage of the oxygen in phosphate isotope paleothermometry is that it is a system which records temperatures with great sensitivity while bone and teeth building organisms are alive and the record is nearly perfectly preserved after death fish from seven water bodies of different temperatures 3 23 c and different 18 o values 16 to 3 of the water were analysed the 18 o values of the analysed po 4 vary from 6 to 25 the system passed the following tests a the temperatures deduced from isotopic analyses of the sequence of fish from lake baikal are in good agreement with the temperatures measured in the thermally stratified lake b the isotopic composition of fish bone phosphate is not influenced by the isotopic composition of the phosphate which is fed to the fish but only by temperature and water composition isotopic analysis of fossil fish in combination with analysis of mammal bones should be a useful tool in deciphering continental paleoclimates

late cretaceous oceans and the cool tropic paradox oxygen isotopic proxies of paleo sea surface temperatures ssts suggest that maastrichtian about 66 million years ago tropical ssts were lower than those of today they also demonstrate that maastrichtian latitudinal sst gradients were much lower than those of the present the low maastrichtian sst gradients indicate that meridional heat transport was much greater or latitudinal differences in the balance of radiation to and from the sea surface were much less extreme during the latest cretaceous than they are today or that both conditions were true these findings challenge traditional interpretations of greenhouse late cretaceous climates

magma faults and gravitational loading at mount etna the 2002 2003 eruptive period 1 mount etna is characterized by a complex structural setting that influences its evolution in order to understand how the interaction between dike forming intrusions and faulting influences the kinematics of the volcanic edifice we developed a numerical model it takes account of the topography the medium heterogeneities the gravitational loading and the most active crustal discontinuities a parameterization of the apparent coefficient of friction as a function of the depth has been considered in the range from 0 01 to 0 5 the density values used young s modulus and poisson s ratio range from about 1700 to 3200 kg m3 8 5 to 140 gpa and 0 15 to 0 35 respectively the model was applied to the 2002 2003 etna eruption the resulting deformation pattern was in agreement with the data provided by the continuous gps stations and the seismological knowledge obtaining displacements up to 1 m some discrepancies between the recorded ground deformation field and the modeled displacements allowed us to make some hypotheses on the volcano tectonic e g for the pernicana fault or regional tectonic origin acireale s alfio fault system of the crustal discontinuities moreover our results suggested that the pernicana fault is characterized by a very low apparent coefficient of friction less than 0 1 furthermore we evaluated the contribution of the gravitational loading and found that it implies a variation of about 10 of the overall deformation pattern our results clearly showed that the weight of the volcanic edifice acts in opposition to the magmatic intrusions conversely we found that the presence of medium heterogeneities may favor the eastern flank movements toward the se and the spreading of the summit area playing a fundamental role in ascending magma finally we investigated the shallow sliding model and found that dike forming intrusions produce negligible displacements less than 1 mm along the subhorizontal detachment surface therefore the gravitational loading during dike forming intrusions is not able to trigger sliding processes along this plane

possible atmospheric co2 extremes of the middle cretaceous late albian turonian 1 atmospheric carbon dioxide co2 estimates for the middle cretaceous mk have a range of 4000 ppm which presents considerable uncertainty in understanding the possible causes of warmth for this interval this paper examines the problem of mk greenhouse forcing from an inverse perspective we estimate upper ocean water temperatures from oxygen isotope measurements of well preserved late albian turonian planktonic foraminifera and compare these against temperatures predicted by general circulation model gcm experiments with co2 concentrations of 500 7500 ppm at least 4500 ppm co2 is required to match maximum temperatures inferred from well preserved planktonic foraminifera approximately 900 ppm co2 produces a good match between the model and the minimum temperature estimates for the mk an ocean model forced by these two extremes in surface conditions brackets nearly all available bottom water temperature estimates for this interval the climate model results support nearly the entire range of mk co2 estimates from proxy data the ocean model suggests possible mk oceanographic changes from deep water formation in the high latitude region of one hemisphere to the other hemisphere in response to changes in atmospheric temperatures and hydrologic cycle strength we suggest that rather than contradicting one another the various proxy co2 techniques especially those with high temporal resolution may capture true variability in co2 concentrations and that mk co2 could have varied by several thousand ppm through this interval

coastal elevation changes in eastern sicily implications for volcano instability at mount etna the eastern flank of mount etna sicily has been recognised as being unstable and three contrasting models have been proposed to account for this phenomenon these being deep seated spreading shallow sliding and tectonic block movements these models are examined by making reference to the rates and patterns of crustal movement along the eastern coastline of sicily as determined from palaeoshoreline data the south eastern coastline of sicily portopalo to catania provides no evidence of holocene emergence in contrast the volcanic coastline catania to capo schiso and the northeastern shoreline taormina to milazzo display widespread evidence of coastal emergence radiocarbon dated remains indicate that both the volcano and northeastern sicily have been uplifted at a rate exceeding 1 5mm yr during holocene times although more recent rates of uplift may have been greater the pattern of uplift suggests that the northeastern coastline of sicily including the volcanic ediface is apparently uplifting as a coherent unit with superficial flank movements being superimposed on a regionally uplifting sub volcanic basement

deep sea paleotemperature record of extreme warmth during the cretaceous oxygen isotope analyses of well preserved foraminifera from blake nose 30 n paleolatitude north atlantic and globally distributed deep sea sites provide a long term paleotemperature record for the late albian maastrichtian interval that is difficult to reconcile with the existence of significant cretaceous ice sheets given reasonable assumptions about the isotopic composition of cretaceous seawater our results suggest that middle bathyal water temperatures at blake nose increased from 12 c in the late albian through middle cenomanian to a maximum of 20 c during the latest cenomanian and earliest turonian bottom waters were again 12 c during the middle campanian and cooled to a minimum of 9 c during the maastrichtian correlative middle bathyal foraminifera from other ocean basins yield paleotemperature estimates that are very similar to those from blake nose comparison of global bottom water temperatures and latitudinal thermal gradients suggests that global climate changed from a warm greenhouse state during the late albian through late cenomanian to a hot greenhouse phase during the latest cenomanian through early campanian then to cool greenhouse conditions during the mid campanian through maastrichtian

equatorial sea surface temperatures for the maastrichtian revealed through remarkable preservation of metastable carbonate the classic paleotemperature record based on 18 o data from pelagic foraminiferal calcite suggests that equatorial sea surface temperatures during the maastrichtian 12 20 c were much cooler than today 27 29 c such cool equatorial temperatures contradict basic theories of tropical atmospheric and ocean dynamics we report 18 o data from remarkably well preserved rudist aragonite and magnesian calcite cements of maastrichtian age 69 1 ma from the carbonate platform of wodejebato guyot in the western pacific these data suggest that equatorial sea surface temperatures in the maastrichtian best estimate 27 32 c were at least as warm as today this finding helps reconcile the geologic 18 o record with ocean atmospheric dynamic theory and implies a reduction in the poleward heat flux required by global climate simulations of greenhouse conditions

tectonic control on the eruptive dynamics at mt etna volcano sicily during the 2001 and 2002 2003 eruptions abstract the eruptive events of the july august 2001 and october 2002 january 2003 at mt etna provide new insights for reconstructing the complex geometry of the feeding system and their relationship to regional tectonics the 2001 eruption took place mainly on the upper southern sector of the volcano the eruption was preceded by a large earthquake swarm for a few days before its onset and accompanied by ground deformation and fracturing the development of surface cracking along with the seismic pattern has allowed us to recognize three distinct eruptive systems the sw ne nnw sse and n s systems which have been simultaneously active such eruptive systems are only the upper portions of a complex feeding system that was fed at the same time by two distinct magmas the sw ne and nnw sse systems connected with the se crater conduit were fed by magma coming from depth whereas the n s system served instead as an ascending pathway for an amphibole bearing magma residing in a shallow reservoir the eruptive activity started again on october 2002 on the ne rift zone where about 20 eruptive vents were aligned between 2500 and 1900 m a s l and on the southern flank from the central crater to the montagnola the onset of eruptive activity was accompanied by a seismic swarm as in the 2001 eruptive event two independent feeding systems formed characterized by distinct magmas the sw ne system controlled the feeding of the northeast rift and was accommodated by left lateral displacement along the wnw ese trending pernicana fault the n s system fed the eruptions on the southern flank moreover the associated crustal deformation triggered seismic reactivation of tectonic structures in the eastern flank of the volcano and offshore these two last eruptions indicate that at mt etna the ascent of magma as well as the accommodation of deformation is strongly dominated by local extensional structures that are connected to a regional tectonic regime

evolution of early cenozoic marine temperatures the equator to high southern latitude sea surface and vertical temperature gradients are reconstructed from oxygen isotope values of planktonic and benthic foraminifers for the following five time intervals late paleocene early eocene early middle eocene late eocene and early oligocene paleotemperatures are calculated using standard oxygen isotope temperature equations with adjustments to account for 1 variations in sea water 18o related to changes in global ice volume over time and 2 latitudinal gradients in surface water 18o these reconstructions indicate that sea surface temperatures sst of the southern oceans in the early eocene were as high as 15 c whereas temperatures during the late paleocene and early middle eocene reached maximum levels of 10 12 c by the late eocene and early oligocene high latitude sst had declined to 6 and 4 c respectively for most of the early paleogene low latitude sub tropical temperatures remained constant and well within the range of holocene temperatures 24 ndash 25 c but by the late eocene and early oligocene declined to values in the range of 18 to 22 c the late paleogene apparent decline in tropical temperatures however might be artificial because of dissolution of near surface foraminifera tests which biased sediment assemblages toward deeper dwelling foraminifera moreover according to recent plate reconstructions it appears that the majority of sites upon which the late eocene and early oligocene tropical temperatures were previously established were located either in or near regions likely to have been influenced by upwelling global deepwater temperature on average paralleled southern ocean sst for most of the paleogene we speculate based on the overall timing and character of marine sea surface temperature variation during the paleogene that some combination of both higher levels of greenhouse gases and increased heat transport was responsible for the exceptional high latitude warmth of the early eocene

desert pavement development on the lake shorelines of lake eyre south south australia abstract to the southwest of lake eyre south south australia silcrete boulders exposed by the erosion of the surrounding fine sediments undergo mechanical weathering to form desert pavement successive palaeoshorelines of lake eyre have exposed an age related sequence of different stages in the weathering of the boulders this study investigates desert pavement development in this saline environment in addition it attempts to develop a model for the development of desert pavement following exposure of the silcrete boulders based on palaeo lake shorelines dated from previous studies seven stages can be recognised corresponding to stages of soil and pavement development prior to stage one is the actual exposure of the boulder as the result of erosion by wave action at the lake shoreline or by erosion as the lake level falls during desiccation at stage 1 the upper surface of the boulder breaks up through mechanical weathering salt weathering while the rest of the boulder is still buried at stage 2 the surface fragments fall to the edge of the stone and expose more of the stone which continues to break up there is no soil development in stages 1 and 2 by stage 3 most of the stone is exposed and broken up making a mini hill at this stage soil development begins with the accumulation of sandy soil between the rock fragments at stage 4 the stones form small cones and the soil is more developed it is sandy with a typical of colour 10 yr 6 6 at stage 5 the stones forming the small cone are completely fragmented stone fragments at the centre are very angular but smoother at the edges of the mini hill as the result of weathering etching by chemical processes soil texture is silty sand and soil colour is 7 5 yr 6 6 at stage 6 the surface is nearly flat the soil is sandy silt and soil colour is between 7 5 yr 5 6 and 7 5 yr 5 8 stage 7a is the gibber plain phase composed of small well rounded stones as a result of continued etching of the edges of the fragmented stones the soil is silty and the soil colour is between 5 yr 5 6 and 5 yr 5 8 stage 7b is also gibber plain with small well rounded stone fragments but where the soil has been replaced by crystalline gypsum this sequence differs from sequences described in other areas especially on alluvial fan or terrace surfaces this may be partly due to the different origin of the clasts as pre weathered silcrete boulders and partly due to the importance of chemical weathering by etching in this salt rich environment

thermal evolution of cretaceous tethyan marine waters inferred from oxygen isotope composition of fish tooth enamels 1 the evolution of subtropical 30 35 n upper ocean temperatures through the cretaceous is inferred from the oxygen isotope compositions of 64 fish teeth enamel coming from the western tethyan platform mean 18o values of 22 at the berriasian valanginian boundary decrease with oscillations to 18 5 around the cenomanian turonian boundary and progressively increase to 21 5 by the end of the cretaceous the similarity of this oxygen isotope curve for bioapatites from platform environments with those for foraminifera and bulk carbonates that were deposited in deeper waters and at other paleolatitudes indicates that they record global climatic signals major cooling events at the million year scale can be distinguished 1 at the berriasian valanginian boundary and 2 during the earliest late valanginian a third cooling event is detected during the earliest aptian these events already proposed as icehouse interludes during the lower cretaceous are also recorded at subtropical latitudes a progressive warming is identified from the aptian to the cenomanian turonian interval that corresponds to a thermal optimum and then upper ocean temperatures decreased to the maastrichtian minimum isotopic temperatures range from 15 c to 28 c assuming a 18oseawater of 1 for an ice free world taking more realistic 18oseawater values of 0 for tropical waters during glacial periods within the berriasian valanginian interval and earliest aptian or with above average salinities possibly the maastrichtian temperatures are increased by 4 5 c temperature differences between climatic extremes of the valanginian and cenomanian turonian are estimated to have been 10 c latitudinal thermal gradients for the albian cenomanian turonian and maastrichtian were 0 2 0 3 c latitude and thus weaker than modern oceanic values at about 0 4 c latitude

thermal excursions in the ocean at the cretaceous tertiary boundary northern morocco δ18o record of phosphatic fish debris c lecuyer p grandjean j r o neil h cappetta and f martineau 1993 thermal excursions in the ocean at the cretaceous tertiary boundary northern morocco c lso record of phosphatic fish debris palaeogeogr palaeoclimatol palaeoecol 105 235 243 high precision oxygen isotope analyses were made of phosphate extracted from 17 samples of nektonic and benthic fish debris sampled across the stratigraphic cretaceous tertiary boundary in northern morocco a refinement of the silver phosphate method was used to isolate phosphate from biogenic materials measured 180 values of 18 6 20 5 o are interpreted as reflecting high resolution thermal variations that affected the ocean water column of the western tethys the warm 27 c water masses that characterized maastrichtian times underwent rapid cooling and stabilized at an average temperature of 19 c during the dano montian and thanetian this period of constant and cool temperature was followed by a relatively rapid but more gradual warming to about 25 c achieved in the middle ypresian significant small shifts in 6180 values between nektonic and benthic fauna recorded only during the stages of rapid warming or cooling may correspond to averaged thermal differences within the water column that developed in response to global climatic changes the indicated temperature distribution could have been caused by thermal changes in the atmosphere rather than some signal carried by deep ocean currents the oxygen isotope data coupled with previous measurements of ree and end ti on the same samples support the suggestion that paleo pacific westward currents progressed as far as the northwestern part of the african platform at the end of the cretaceous period

heat transport deep waters and thermal gradients coupled simulation of an eocene greenhouse climate for the first time a coupled general circulation model with interactive and dynamical atmospheric oceanic and sea ice components is used to simulate an eocene 50 ma greenhouse climate we introduce efficient ocean spin up methods for coupled paleoclimate modeling sea surface temperatures ssts and salinities evolve unconstrained producing the first proxy data independent estimates for these eocene climate parameters tropical and extratropical model predicted ssts are warmer than modern values by 3 and 5 c respectively salinity driven deep water formation occurs in the north atlantic and tethys the zonal average overturning circulation is weaker than modern eocene ocean heat transport is 0 6 pw less than modern in the northern hemisphere and 0 4 pw greater in the southern hemisphere the model predicted near modern vertical and meridional eocene temperature gradients imply that the dominant theory for maintaining low gradients increased ocean heat transport is incorrect or incomplete and other mechanisms should be explored

geomorphology and seismotectonic elements in the giarre area sicily a morphostructural analysis has been performed on the eastern flank of mt etna located between the towns of st alfio and linera and the ionian sea the research has been carried out through analysis of aerial photographs and has allowed recognition of morphoneotectonic elements such as some scarps with rectilinear trend laterally becoming morphological flexures according to the lithology anomalies in the hydrographic network such as rectilinear tracts of drainage valleys with simple or double bends hanging valleys and truncated valleys narrow deeply engraved valleys with meanders and fluvial captures all these elements are caused by a fault system oriented nnw sse with a mainly vertical component seismic events with very shallow foci have been recorded in the study area these earthquakes triggered several small landslides on the fault scarps and large series of coseismic and coaxial fractures it is possible to show that the morphostructures examined have been reactivated during many of the seismic events that have occurred in the area the combination of these elements verifies that the morphostructures have a real neotectonic cause which is associated with uplifts which have occurred in the area at different times