effects of direct and indirect heating on the validity of rock weathering simulation studies and durability tests rock surface and subsurface temperature responses in samples exposed to direct heating insolation under natural hot desert conditions reveal considerable variability between lithologies related to differences in thermal properties especially albedo and thermal conductivity however when the same samples are heated indirectly by air in an oven based environmental cabinet lithological differences in temperature response disappear and all samples attain temperatures similar to the air temperature within the cabinet rates and patterns of rock decay produced in such environmental cabinets may not therefore reflect those encountered under natural conditions where breakdown is related to micro environmental conditions at the rock air interface and where rock temperature is one of the most important controlling factors in addition to implications for assessment of weathering effectiveness use of only indirect forms of heating affects the determination of comparative rock durability because all rock types are cycled through the same temperature regimes because temperature exerts such a major control on rock breakdown through its control on physical and chemical weathering processes all significant factors influencing it must be included in the design of weathering simulations and durability tests

critical degree of saturation a control factor of freeze thaw damage of porous limestones at castle of chambord france abstract the paper analyzes the petrophysical and mechanical properties of two porous limestones that were used in the construction and restoration works at the castle of chambord in france a unesco world heritage site the original construction material the tuffeau limestone with a total porosity of 45 0 6 and the replacement stone of later restorations the richemont limestone with a total porosity of 29 0 7 were subjected to freeze thaw tests under laboratory conditions to evaluate the role of critical degree of saturation and pore size distribution in frost damage laboratory tests were coupled with in situ measurements of temperature and relative humidity at stone surface at the castle of chambord in situ data show that the stones in the castle experienced several freezing thawing cycles annually the limestone samples under laboratory conditions were subjected to up to 50 freeze thaw cycles under eight different degrees of saturations the total porosity tensile strength ultrasonic pulse velocity the mercury intrusion porosimetry and scanning electron microscopy techniques were employed to analyze the conditions of samples during the cycles the experimental results show that when the degree of saturation of the two studied limestones exceeds 80 85 the freeze thaw damage occurs even after a few freeze thaw cycles the effect of freezing is very fast if the water saturation is sufficient moreover results indicate that these stones have the same critical degree of saturation of about 85 despite the differences in porosity finally the results indicate that the increase in the number of freezing thawing cycles has no effect on the critical degree of saturation but the frost damage is mostly controlled by pore size distribution rather than by total porosity accordingly critical degree of saturation can be defined as an intrinsic stone property

microstructural and geochemical perspectives on planktic foraminiferal preservation glassy versus frosty in recent years it has become apparent that the cool tropic paradox of paleogene and cretaceous greenhouse climates arises because of the diagenetic alteration of tropical planktic foraminiferal calcite near the seafloor yielding artificially high 18o values because the mg ca compositions of foraminiferal and inorganic calcite are thought to be quite different mg ca measurements should be a sensitive way of monitoring diagenetic alteration here we examine the extent of diagenetic alteration of eocene planktic foraminiferal calcite using scanning electron microscope imaging of foraminiferal test microstructures and geochemical 18o and mg ca analyses we compare microstructural and geochemical characteristics between given species exhibiting two contrasting states of preservation those that appear frosty under reflected light and those that appear glassy microstructural evidence reveals extensive diagenetic alteration of frosty foraminiferal tests at the micron scale while 18o analyses document consistently higher 18o and therefore lower paleotemperatures in this material yet we find that 18o offsets between species in these frosty foraminiferal assemblages appear to be generally preserved suggesting that frosty foraminifera remain valuable for generating relatively short approximately 1 myr paleoceanographic time series that do not demand absolute estimates of paleotemperature we also find that the observed increase in mg ca for planktic foraminifera exhibiting diagenetic alteration compared to glassy taphonomies is far smaller than would be expected from the addition of inorganic calcite based on laboratory derived mg2 partition coefficients our findings imply that a much lower mg2 partition coefficient controls inorganic calcite formation in deep sea sedimentary sections in accordance with the findings of baker et al 1982

efficacy of δ18o data from pliocene planktonic foraminifer calcite for spatial sea surface temperature reconstruction comparison with a fully coupled ocean atmosphere gcm and fossil assemblage data for the mid pliocene sea surface temperature sst estimates using the 18o composition of fossil planktonic foraminifer calcite within the time slice 3 12 to 3 05 ma pliocene kaena subchron c2an1r are assessed for nine atlantic ocean sites these are compared with sst estimates from fossil assemblages for the time slab 3 29 2 97 ma and with estimates from a fully coupled ocean atmosphere general circulation model gcm for the same time interval most sst estimates derived from the 18o data indicate a cooler ocean surface than at present through the latitudinal range 69 25 n to 46 88 s at some sites the temperature difference is greater than 5 c cooler than at present this contrasts with sst estimates from fossil assemblages that give warmer than present temperatures at mid to high latitudes and similar temperatures in the tropics and with the gcm which predicts ssts warmer than at present across all latitudes for this time interval difficulties interpreting the ecology of fossil foraminifer assemblages and inaccurate estimates of mid pliocene seawater 18o composition 18osw at some sites may partly produce the temperature discrepancy between isotope based and fossil based sst estimates but do not adequately explain the cool signal of the former we interpret the cool sst estimates from the 18o data to be the product of a calcite formed at a level deep within or below the ocean mixed layer during the life cycle of the foraminifera b secondary calcite with higher 18o formed in the planktonic foraminifer tests in sea bottom pore waters although these effects differ between sites secular and temporal oceanographic trends are preserved in the primary calcite formed in the mixed layer near the ocean surface witnessed by the latitudinal variation in estimated ssts reconstructing accurate mid pliocene ssts with much of the existing published oxygen isotope data probably requires a detailed re assessment of taphonomy particularly at tropical sites this study also indicates that methods for estimating atlantic pliocene 18osw need to be refined

specimen size effects on behavior of loose sand in triaxial compression tests triaxial tests are often used to determine the behavior and strength characteristics of soils without due attention to the differences in specimen size several drained and undrained monotonic triaxial compression shear tests are performed in this study on three different specimen sizes of the same sand to investigate the influence of specimen size and scale effect on sand compression and shear behavior the behavior of a sand specimen is strongly influenced by shear banding and specimen boundary conditions which are manifested as specimen size effects in the test results of this study the measured sand compressibility and shear strength parameters are employed to describe scale effects and investigate specimen size effects in liquefaction triggering analysis the results show that while larger specimens exhibit a less compressible behavior during isotropic compression larger shear strengths and effective friction angles are mobilized in the smaller specimens during shearing a number of geotechnical

alkenone and boron based pliocene pco2 records abstract the pliocene period is the most recent time when the earth was globally significantly 3 c warmer than today however the existing pco2 data for the pliocene are sparse and there is little agreement between the various techniques used to reconstruct palaeo pco2 this disagreement coupled with the general low temporal resolution of the published records does not allow a robust assessment of the role of declining pco2 in the intensification of the northern hemisphere glaciation inhg and a direct comparison to other proxy records are lacking for the first time we use a combination of foraminiferal 11b and organic biomarker alkenone derived carbon isotopes proxies to determine the concentration of atmospheric co2 over the past 5 ma both proxy records show that during the warm pliocene pco2 was between 330 and 400 ppm i e similar to today the decrease to values similar to pre industrial times 275 285 ppm occurred between 3 2 ma and 2 8 ma coincident with the inhg and affirming the link between global climate the cryosphere and pco2

a revised early miocene age for the instigation of the eirik drift offshore southern greenland evidence from high resolution seismic reflection data abstract the eirik drift lies on the continental slope south of greenland where it has been formed under the influence of northern component water ncw ncw flow is an essential part of the global thermohaline circulation thc which is closely connected to the world s climate changes in pathways and intensity of ncw flow bear information about modifications of the north atlantic thc in a changing climate there is some disagreement about when deep current controlled sedimentation at the eirik drift started while the onset of drift building was previously dated as early pliocene or late miocene in age we suggest that the effect of large scale current deposition had been initiated by at least 19 17 ma based on the seismostratigraphic analysis of sedimentary structures identified in a set of high resolution seismic reflection data this assumption of an early miocene onset of ncw flow is supported by regional evidence regarding the breaching of the greenland scotland ridge which is documented in several erosional unconformities within the north atlantic after the onset of deep current controlled sedimentation at the eirik drift two major changes in the deep current system are revealed during the miocene at the mid to late miocene boundary 12 10 ma and at 7 5 ma

low frequency pliocene climate variability in the eastern nordic seas the pliocene 5 3 2 6 ma is often described as a relatively stable climatic period with warm temperatures characterizing high latitudes new suborbital resolved stable isotope records from ocean drilling program hole 642b in the eastern nordic seas document that the pliocene was not a stable period characterized by one climate rather seven distinct climate phases each lasting between 150 000 and 400 000 years are identified and characterized in the time interval 5 1 3 1 ma four of the transitions between the defined climate phases occurred close to an eccentricity minimum and a minimum in amplitude of change for northern hemisphere summer insolation while two occurred around an eccentricity maximum and a maximum in amplitude in insolation change hence a low frequency response of the nordic seas to insolation forcing is indicated in addition paleogeographic and related paleoceanographic changes expansion of the arctic sea ice cover and onset of northern hemisphere glaciation were important factors behind the evolving pliocene low frequency variability in the eastern nordic seas it is likely that the identified climate phases and transitions are important beyond the nordic seas due to their association with changes to both insolation and paleogeography however a strong and variable degree of diagenetic calcite overgrowth is documented for the planktic foraminifera especially influencing the planktic 18o results the absolute values and amplitude of change cannot be taken at face value

pliocene pleistocene ice rafting history and cyclicity in the nordic seas during the last 3 5 myr a continuous 3 5 myr ird record was produced from ocean drilling program odp site 907 a timescale based on magnetic polarity chrons oxygen isotope stratigraphy for the last 1myr and orbital tuning was developed the record documents a stepwise inception of large scale glacial cycles in the nordic seas region the first being a marked expansion of the greenland ice sheet at 3 3 ma a second step occurred at 2 74 ma by an expansion of large scale ice sheets in the northern hemisphere ice sheet variability around the nordic seas was tightly coupled to global ice volume over the past 3 3 myr between 3 and 1 ma most of the variance of the ird signal is in the 41 kyr band whereas the last 1 myr is characterized by stronger 100 kyr variance the gamma ray porosity evaluator grape density record is closely linked with ird variations and documents sub orbital variability resembling the late quaternary heinrich bond cycles

paleoceanography of the last interglacial glacial cycle in the polar north atlantic abstract using to its position close to the sites of waxing and waning of the major northern hemisphere ice sheets during the late quaternary climatic cycles the polar north atlantic plays a key role in driving global change therefore analyzing the present day sedimentation processes and reconstructing the late quaternary paleoceanography in this region has been a focus of major scientific interest through the last fifteen years this paper aims to combine the vast amount of new results about modern sediment fluxes surface sediment distribution and the paleoceanographic record and to present a comprehensive overview of the paleoceanography in the polar north atlantic through the last 200 000 years which is based on the basinwide analysis of carbonate and ice rafted detritus records during the last fifteen years the climap paleoceanographic view of the glacial polar north atlantic as an almost permanently isolated sea covered by heavy sea ice throughout the year has been shifted to a much more dynamic view of the environmental conditions a meridional current system similar to the present day conditions secured the exchange of water ice and heat between the polar north atlantic and the alantic and arctic oceans although affected by variations in strength and intensity this meridional current pattern resulted in an almost permanent presence of at least some seasonally ice free areas with all the consequences for e g marine life and deep water formation in addition the development of the continental ice sheets namely the fennoscandian and the barents sea ice sheets is closely related to this dynamic circulation pattern during the so called nordway events the pronounced inflow of temperate waters from the south provided moisture for the growth of the ice sheets the most prominent of these events stage 6 stage 4 and substage 3 1 2 ended in major glaciations reflected in the terrestrial sequences and in the deep sea ird records

the non analogue nature of pliocene temperature gradients abstract the strong warming of the north atlantic and high latitudes in the pliocene 5 3 2 6 million years ago continually fails to be simulated in climate model simulations being the last period of earth history with higher global temperatures and carbon dioxide levels similar to today it is an important target period for palaeoclimate models one of the key features of the pliocene climate is the reduced meridional gradients particularly in the high latitudes of the northern hemisphere here we show that previously unconsidered palaeogeographic changes river routing ocean bathymetry and additional landmass in the modern barents sea in the north atlantic region can produce significant temperature responses at high latitudes along with orbital forcing this can significantly decrease equator to pole temperature gradients in the atlantic ocean these additional forcings show that the large arctic warming and significantly reduced temperature gradients in the pliocene are not analogous to future warming and that careful consideration of all the possible climatic forcings is required to accurately simulate pliocene climate

in situ δ18o and mg ca analyses of diagenetic and planktic foraminiferal calcite preserved in a deep sea record of the paleocene eocene thermal maximum we report 18o and minor element mg ca sr ca data acquired by high resolution in situ secondary ion mass spectrometry sims from planktic foraminiferal shells and 100 500 m sized diagenetic crystallites recovered from a deep sea record odp site 865 of the paleocene eocene thermal maximum petm the 18o of crystallites 1 2 pee dee belemnite pdb is 4 8 higher than that of planktic foraminiferal calcite 3 6 pdb while crystallite mg ca and sr ca ratios are slightly higher and substantially lower than in planktic foraminiferal calcite respectively the focused stratigraphic distribution of the crystallites signals an association with petm conditions hence we attribute their formation to early diagenesis initially sourced by seafloor dissolution burndown ensued by reprecipitation at higher carbonate saturation the mg ca ratios of the crystallites are an order of magnitude lower than those predicted by inorganic precipitation experiments which may reflect a degree of inheritance from donor phases of biogenic calcite that underwent solution in the sediment column in addition sims 18o and electron microprobe mg ca analyses that were taken within a planktic foraminiferal shell yield parallel increases along traverses that coincide with muricae blades on the chamber wall the parallel 18o and mg ca increases indicate a diagenetic origin for the blades but their 18o value 0 5 pdb is lower than that of crystallites suggesting that these two phases of diagenetic carbonate formed at different times finally we posit that elevated levels of early diagenesis acted in concert with sediment mixing and carbonate dissolution to attenuate the 18o decrease signaling petm warming in whole shell records published for site 865

the occurrence of gypsum in the scaling of stones at the castle of chambord france the main cause of degradation in tuffeau a soft siliceous and clayey limestone extensively used in the construction of the castles of the loire valley in france is scaling the most damaging form of weathering is spalling over time a plaque several centimetres in thickness gradually forms under the stone surface and eventually falls away leaving the resulting new surface powdered hypotheses regarding the initiation and development of such degradation have not yet met scientific consensus the objective of the present paper is to improve existing knowledge of scaling degradation by analysing in situ samples representing different stages of the same degradation process the analysis of the stones at the castle of chambord revealed the presence of gypsum caso4 2h2o mainly located in cracks parallel to the stone surface this gypsum was then studied in terms of its crystal morphology and distribution with depth for comparison purposes another form of scaling identified at the castle of chambord but rarely studied flaking was also examined a first attempt at explaining the origin and formation of the observed gypsum in both scaling processes was conducted by interacting and comparing the characterisation results with historical and environmental data

orbitally paced climate oscillations across the oligocene miocene boundary the late oligocene and early miocene periods some 21 to 27 million years ago have generally been viewed as times of moderate global warmth and ice free conditions yet several lines of evidence suggest that this interval was punctuated by at least one and possibly several episodes of high latitude cooling and continental glaciation1 2 3 here we present stable isotope and per cent coarse fraction data from an equatorial western atlantic deep sea sediment core that provide high resolution records of the climate variability across the oligocene miocene transition 22 5 25 7 million years ago a strong 40 kyr periodicity in the oxygen isotope record is consistent with a high latitude orbital obliquity control on ice volume and temperature orbital influences are also apparent at precession and eccentricity frequencies including a series of 400 kyr oscillations that culminate in distinct maxima at the oligocene miocene boundary about 23 7 million years ago covariance between the carbon and oxygen isotope records suggests that the oceanic carbon cycle may have contributed to global cooling during the 400 kyr cycles particularly at the oligocene miocene boundary

effect of thermal stress condensation and freezing thawing action on the degradation of stones on the castle of chambord france this work consists in estimating the role of climatic conditions in the degradation of two french limestones tuffeau and richemont stone used in the construction and the restoration of the castle of chambord the largest castle in the loire valley france meteorological data air temperature air relative humidity and rainfall were statistically analysed in combination with stone data from thermal humidity sensors inserted into the walls the climatic conditions of the surrounding area were described to assess their role in enhancing the degradation of the stones through three weathering processes thermal stress condensation and freezing thawing the damage risks due to the weathering processes were taken into account not only through the bulk effects on the stone surfaces but also their effects were extended to investigate the damage that occurs within the porous structure of the stone field observations showed that the main patterns of degradation affecting the stones of the castle are biological colonization and stone detachment in the form of stone spalling and exfoliation the results of the analysis show that there is no risk of damage to the stones due to thermal stress moreover the two stones experience similar overall trends against freezing thawing processes finally this study clearly highlights the important role of condensation in the degradation of the stones of the castle

geomorphology s role in the study of weathering of cultural stone abstract great monumental places petra giza angkor stonehenge tikal macchu picchu rapa nui to name a few are links to our cultural past they evoke a sense of wonderment for their aesthetic fascination if not for their seeming permanence over both cultural and physical landscapes however as with natural landforms human constructs are subject to weathering and erosion indeed many of our cultural resources suffer from serious deterioration some natural some enhanced by human impact groups from the united nations to local civic and tourism assemblies are deeply interested in maintaining and preserving such cultural resources from simple rock art to great temples geomorphologists trained in interacting systems process and response to thresholds rates of change over time and spatial variation of weathering processes and effects are able to offer insight into how deterioration occurs and what can be done to ameliorate the impact review of recent literature and case studies presented here demonstrate methodological and theoretical advances that have resulted from the study of cultural stone weathering because the stone was carved at a known date to a baseline or zero datum level some of the simplest methods e g assessing surface weathering features or measuring surface recession in the field provide useful data on weathering rates and processes such data are difficult or impossible to obtain in natural settings cultural stone weathering studies demonstrate the importance of biotic and saline weathering agents and the significance of weathering factors such as exposure microclimate and human impact more sophisticated methods confirm these observations but also reveal discrepancies between field and laboratory studies this brings up two important caveats for conservators and geomorphologists for the conservator are laboratory and natural setting studies really analogous and useful for assessing stone damage for the geomorphologist does cultural stone data have any real relevance to the natural environment these are questions for future research and debate in any event cultural stone weathering studies have been productive for both geomorphologists and conservators continued collaboration and communication between the geomorphic historic preservation archaeological and engineering research communities are encouraged

neogene overflow of northern component water at the greenland scotland ridge in the north atlantic ocean flow of north atlantic deep water nadw and of its ancient counterpart northern component water ncw across the greenland scotland ridge gsr is thought to have played an important role in ocean circulation over the last 60 ma the iceland plume has dynamically supported an area which encompasses the gsr consequently bathymetry of the gsr has varied with time due to a combination of lithospheric plate cooling and fluctuations in the temperature and buoyancy within the underlying convecting mantle here we reassess the importance of plate cooling and convective control on this northern gateway for ncw flow during the neogene period following wright and miller 1996 to tackle the problem benthic foraminiferal isotope data sets have been assembled to examine 13c gradients between the three major deep water masses i e northern component water southern ocean water and pacific ocean water composite records are reported on an astronomical timescale and a nonparametric curve fitting technique is used to produce regional estimates of 13c for each water mass confidence bands were calculated and error propagation techniques used to estimate ncw and its uncertainty despite obvious reservations about using long term variations of 13c from disparate analyses and settings and despite considerable uncertainties in our understanding of ancient oceanic transport pathways the variation of ncw through time is consistent with independent estimates of the temporal variation of dynamical support associated with the iceland plume prior to 12 ma 13c patterns overlap and ncw cannot be isolated significant long period variations are evident which are consistent with previously published work from 12 ma when lithospheric cooling probably caused the gsr to submerge completely long period 13c patterns diverge significantly and allow reasonable ncw estimates to be made our most robust result is a dramatic increase in ncw overflow between 6 and 2 ma when dynamical support generated by the iceland plume was weakest between 6 and 12 ma a series of variations in ncw overflow have been resolved

high amplitude variations in north atlantic sea surface temperature during the early pliocene warm period 1 we provide the first continuous orbital resolution sea surface temperature sst record from the high latitude north atlantic a region critical to understanding the origin of the plio pleistocene ice ages and proximal to regions that became frequently glaciated after 2 7 ma we analyzed sediments from ocean drilling program site 982 over the last 4 ma for their alkenone unsaturation index and compared this surface water signal to a benthic 18o record obtained from the same section we find that while ocean surface temperatures were significantly warmer 6 c than modern temperatures during the early pliocene they were also as variable as those during the late pleistocene a surprising result in light of the subdued variance of oxygen isotopic time series during the interval of 3 5 ma we propose two possible explanations for the high orbital scale sst variability observed either that a strong high latitude feedback mechanism not involving large continental ice sheets alternately cooled and warmed a broad region of the northern high latitudes or that by virtue of its location near the northern margin of the north atlantic drift the site was unusually sensitive to obliquity driven climate shifts on supraorbital time scales a strong sustained cooling of north atlantic ssts 4 5 c occurred from 3 5 to 2 5 ma and was followed by an interval of more modest cooling an additional 1 5 c from 2 5 ma to the present evolutionary orbital scale phase relationships between north atlantic sst and benthic 18o show that sst began to lead 18o significantly coincident with the onset of strong cooling at site 982 3 5 ma we speculate that these changes were related to the growth and subsequent persistence of a greenland ice sheet of approximately modern size through interglacial states

rapid changes in the mechanism of ocean convection during the last glacial period high amplitude rapid climate fluctuations are common features of glacial times the prominent changes in air temperature recorded in the greenland ice cores1 2 are coherent with shifts in the magnitude of the northward heat flux carried by the north atlantic surface ocean3 4 changes in the ocean s thermohaline circulation are a key component in many explanations of this climate flickering5 here we use stable isotope and other sedimentological data to reveal specific oceanic reorganizations during these rapid climate change events deep water was generated more or less continuously in the nordic seas during the latter part of the last glacial period 60 to 10 thousand years ago but by two different mechanisms the deep water formation occurred by convection in the open ocean during warmer periods interstadials but during colder phases stadials a freshening of the surface ocean reduced or stopped open ocean convection and deep water formation was instead driven by brine release during sea ice freezing these shifting magnitudes and modes nested within the overall continuity of deep water formation were probably important for the structuring and rapidity of the prevailing climate changes

late neogene history of deepwater ventilation in the southern ocean we compiled carbon isotope records from the north atlantic south atlantic and pacific oceans to estimate changes in vertical and interbasinal 13c gradients for the last 9 myr benthic 13c values of deep water in the south atlantic decreased in a series of steps at 7 2 75 and 1 55 ma away from the north atlantic and toward the pacific the benthic 13c of intermediate water in the south atlantic evolved differently from deep waters resulting in an increase in the intermediate to deep 13c gradient 13cid the 13cid increased in steps at 2 75 and 1 55 ma marking the development and intensification of a chemical divide in the atlantic ocean between well ventilated intermediate water and poorly ventilated deep water we suggest these changes in interbasinal and vertical gradients resulted from decreasing northern component water and reduced ventilation of southern component water scw the latter was caused by several interrelated processes in antarctic sources areas including increased sea ice cover enhanced surface water stratification decreased ekman induced upwelling and reduced vertical mixing across the thermocline because antarctic surface water processes and deepwater ventilation rates ultimately influence atmospheric co2 concentration these processes may have acted as a positive feedback that contributed to the major cooling steps in late neogene climate

a high resolution study of holocene paleoclimatic and paleoceanographic changes in the nordic seas 1 high resolution records from images core md95 2011 in the eastern norwegian sea provide evidence for relatively large and small scale high latitude climate variability throughout the holocene during the early and mid holocene a situation possibly driven by consistent stronger westerlies increased the eastward influence of arctic intermediate and near surface waters for the late holocene a relaxation of the atmospheric forcing resulted in increased influence of atlantic water the main changes in holocene climate show no obvious connection to changing solar irradiance and spectral analysis reveals no consistent signature for any periodic behavior of holocene climate at millennial or centennial timescales there are however indications of consistent multidecadal variability

microclimate and weathering in the central namib desert namibia data on rock surface microclimates at four sites kleinberg vogelfederberg gobabeb and ganab along a transect across the central namib desert over a 3 year period have been collected alongside some shorter term data sets rock surface temperature rst air temperature wind relative humidity and surface wetness data are presented here weathering of exposure blocks of local marble and granite has also been monitored over the 3 year period with change observed visually and with scanning electron microscopy complex temporal patterns of rock temperature fluctuations are observed over the 3 years although the four sites show very similar overall trends suggesting spatial homogeneity in the rock surface temperature regime relative humidity and surface wetness data show clear differences between the four sites related to the frequency of fogs granite blocks show no visible changes after 2 years of weathering whereas marble blocks especially those at ganab show sem evidence of structural weakening after 1 year

effect of the formation of the isthmus of panama on atlantic ocean thermohaline circulation the late cenozoic closure of the seaway between the north andsouth american continents is thought to have caused extensive changes in ocean circulation and northern hemisphere climate1 2 but the timing and consequences of the emergence of the isthmus of panama which closed the seaway remain controversial1 2 3 4 5 here we present stable isotope and carbonate sand fraction records from caribbean sediments which when compared to atlantic and pacific palaeoceanographic records indicate that the closure caused a marked reorganization of ocean circulation starting 4 6 million years ago shallowing of the seaway intensified the gulf stream and introduced warm and saline water masses to high northern latitudes these changes strengthened deep water formation in the labrador sea over the next million years as indicated by an increased deep water ventilation and carbonate preservation in the caribbean sea and favoured early pliocene warming of the northern hemisphere the evaporative cooling of surface waters during north atlantic deep water formation would have introduced moisture to the northern hemisphere although the pronounced intensification of northern hemisphere glaciation between 3 1 and 2 5 million years ago substantially lagged the full development of north atlantic deep water formation we propose that the increased atmospheric moisture content was a necessary precondition for ice sheet growth which was then triggered by the incremental changes in the earth s orbital obliquity

early holocene temperature variability in the nordic seas the role of oceanic heat advection versus changes in orbital forcing received 7 january 2011 revised 15 july 2011 accepted 21 july 2011 published 22 october 2011 1 the separate roles of oceanic heat advection and orbital forcing on influencing early holocene temperature variability in the eastern nordic seas is investigated the effect of changing orbital forcing on the ocean temperatures is tested using the 1dice model and the 1dice results are compared with new and previously published temperature reconstructions from a transect of five cores located underneath the pathway of atlantic water from the faroe shetland channel in the south to the barents sea in the north the stronger early holocene summer insolation at high northern latitudes increased the summer mixed layer temperatures however ocean temperatures underneath the summer mixed layer did not increase significantly the absolute maximum in summer mixed layer temperatures occurred between 9 and 6 ka bp representing the holocene thermal maximum in the eastern nordic seas in contrast maximum in northward oceanic heat transport through the norwegian atlantic current occurred approximately 10 ka bp the maximum in oceanic heat transport at 10 ka bp occurred due to a major reorganization of the atlantic ocean circulation entailing strong and deep rejuvenation of the atlantic meridional overturning circulation combined with changes in the north atlantic gyre dynamic causing enhanced transport of heat and salt into the nordic seas

paleoenvironmental changes in the norwegian sea and the northeast atlantic during the last 2 8 m y deep sea drilling project ocean drilling program sites 610 642 643 and 644 sedimentological isotopic and magnetostratigraphic investigations of ocean drilling program and deep sea drilling project sites 642 643 644 and 610 document the oceanographic and climatic evolution of the norwegian sea and the northeastern atlantic over the last 2 8 m y the results show that a major expansion of the scandinavian ice sheet to the coastal areas took place at about 2 56 ma relatively severe glacials appeared until about 2 ma the period 2 6 1 2 ma experienced in general cold surface water conditions with only a weak influx of temperate atlantic water as compared with late quaternary interglacials the norwegian sea was a sink of deep water through this period but deepwater ventilation was reduced and calcite dissolution was high compared with the holocene deep water formed by other mechanisms than it does today between 2 and 1 2 ma the glaciations in scandinavia were small a transition toward larger glacials took place during the period 1 2 to 0 6 ma corresponding to warmer interglacials and reduced calcite dissolution only during the last 0 6 m y has the oceanographic and climatic system of the norwegian sea varied in the manner described in previous studies of the late quaternary a strong thermal gradient was present between the norwegian sea and the northeastern atlantic during the matuyama 2 5 0 7 ma this is interpreted as a sign of a more zonal and less meridional climatic system over the region compared with the present situation

a decay function model for the integrity loss of rock when subjected to recurrent cycles of freezing thawing and heating cooling rocks are used in engineering works as monument or building stone and as architectural covering stone as a result they can be subjected to recurrent cycles of freezing and thawing and will be subjected to heating and cooling they loose some of their integrity under these cyclic temperature variations and the more frequent and severe these cycles the higher the integrity loss however the rates of progressive disintegration is not the same for different rock types or even within rock types this paper presents a mathematical model describing the integrity loss process when a rock is subjected to such recurrent cycles the model postulates a first order process and provides meaningful parameters for the integrity characteristic of rocks the validity of the model has been established by an experimental laboratory study carried out on 10 different rock types