stratigraphic overview of palaeogene tuffs in the faroe shetland basin ne atlantic margin tuffs form key stratigraphic markers that assist with determining the timing of volcanic margin development a number of laterally extensive tuffs are preserved along the north atlantic margin in the offshore faroe shetland basin fsb a product of early palaeogene volcanism associated with the break up and seafloor spreading between greenland and nw europe these tuffs which are dominantly basaltic in composition are widely preserved in the contiguous north sea basin however less attention has been paid to them in the fsb this study integrates multiple regional datasets including 3d seismic data and released commercial well logs to detail the character and distribution of early palaeogene tuffs in the fsb the earliest tuffs are more locally identified by their presence in core whereas later tuffs are more regionally recognizable highlighting more widespread volcanism with time the distribution of tuffs also reveals the timing of formation of the previously enigmatic volcanic centres importantly owing to constraints of vertical resolution in well data we argue that the number of tuffs in the north atlantic margin is probably underestimated and biased towards basaltic tuffs which are easier to identify on well logs

tropical cyclone variations in louisiana u s a since the late eighteenth century 1 plentiful documentary and pre twentieth century instrumental data from louisiana u s a provide a record of continuous tropical cyclones with daily resolution dating back to the late eighteenth century the reconstruction provided new specific information for 83 storms prior to 1872 parts of the early and mid nineteenth century exhibit greater tropical cyclone and hurricane activity than at any time within the last few hundred years a major hurricane that impacted southeast louisiana in august 1812 is very likely the closest landfalling hurricane known to impact new orleans the longer temporal perspective provides insight on historical hurricane impacts and information on assessing future hurricane mitigation strategies concerning potential worst case scenarios

palaeobiogeography and palaeogeographical implications of permian marine bivalve faunas in northeast asia kolyma omolon and verkhoyansk okhotsk regions northeastern russia abstract the paper considers the biogeography and palaeogeographic implications of the permian marine bivalve faunas of northeast asia with a focus on the dynamic relationships between biotic similarities and palaeogeographic distance through an interval of ca 50 million years a stage by stage time series analysis of the biotic similarities between two previously recognized biochores in northeast asia the kolyma omolon and verkhoyan okhotsk provinces has been carried out using both the jaccard and dice similarity indices based on the spatio temporal distributions of 355 permian marine bivalve species in northeast asia the outcome of this analysis combined with other empirical data and previously published tectonic sedimentological and palaeontological information suggests that 1 the bivalve faunas from these two provinces were distinctive from one another as two separate biochores throughout all but the earliest asselian permian stages and 2 the biotic similarities between the verkhoyan okhotsk and kolyma omolon provinces remained consistently low since sakmarian all falling well below the minimum threshold of the jaccard index of 0 42 required for distinguishing marine biotic provinces we interpret these below threshold jaccard biotic similarities as an indication of significant palaeogeographic separation between the verkhoyan okhotsk and kolyma omolon provinces which is in turn considered to indicate rifting and sea floor spreading of the omolon microcontinent and associated terranes and island arcs away from the north asian craton at least from the sakmarian to the beginning of the late permian palaeo distance separation appears to be the primary and most significant biogeographic determinant in accounting for the differences in the spatial distribution of most permian bivalve species in northeast asia several other variables also appear to have played a significant role including regional climate conditions ocean currents and merged island chains as geographic barriers in particular the relatively high biotic similarity between the verkhoyan okhotsk and kolyma omolon provinces during the late wuchiapingian and changhsingian may have been related to the shallowing of the deep water basins oimyakon ayan yuryakh balygychan and sugoi basins that had previously separated the two provinces and the flooding submergence of the okhotsk taigonos volcanic arc system thus allowing the invasion of lower latitude warm water palaeotethyan and even gondwanan species into northeast asia

k ar and 39ar 40ar whole rock dating of zeolite facies metamorphosed flood basalts the upper paleocene basalts of the faroe islands ne atlantic

faunal turnover and changing oceanography late palaeozoic warm to cool water carbonates sverdrup basin canadian arctic archipelago abstract carbonate sedimentary rocks in the fosheim hamilton sub basin at the eastern end of the sverdrup basin contain a particularly sensitive record of changing palaeoceanography and faunal turnover during the northward movement of pangaea through the late palaeozoic carboniferous and earliest permian inner ramp carbonates are a photozoan association of colonial corals fusulinids algae and ooids with sparse heterozoan elements crinoids brachiopods and bryozoans based on modern analogues these biotic components reflect warm water oligotrophic marine environments contemporaneous mid ramp and basin biotas are dominated by a heterozoan fauna solitary corals crinoids bryozoans and brachiopods that grew in cooler deeper waters that may have been beneath a thermocline initial cooling began in the latest sakmarian with an influx of cool deep water and climatic deterioration allowing cool and warm waters to mix disrupting the thermocline and producing a sub tropical marine biota whose remains were reworked by storms and re deposited as tempestites faunas are heterozoan crinoids bryozoans brachiopods and sponges with photozoan elements colonial corals and symbiont bearing fusulinids prominent only in inner ramp facies by late artinskian these photozoan components are only present in shallowest basin margin environments artinskian subtropical waters contained somewhat elevated trophic resources that together with mixing of photozoan and heterozoan elements in the subtropical inner ramp produced the greatest faunal diversity seen in the sverdrup basin the biota was completely boreal in nature and warm shallow waters with a warm refuge biota were now supplemented by cool waters derived from the panthalassa ocean profound change took place in the kungurian coincident with localised uplift during the melville disturbance and increased siliciclastic input neritic storm dominated sediments are wholly heterozoan brachiopods bryozoans crinoids and sponges with no remaining photozoan elements nutrient levels are elevated but not eutrophic as indicated by phosphate and glauconite extensive bioerosion numerous infaunal foraminifers and an impressive and diverse shelly biota that during times of high siliciclastic input was replaced by a profuse zoophycos infauna brachiopod and bryozoan faunas are distinctly boreal continued cooling relatively high nutrients as indicated by abundant glauconite and phosphate and decreased siliciclastic input eventually resulted in an abundant heterozoan biota brachiopods bryozoans crinoids and sponges with local gigantism but reduced brachiopod and bryozoan diversity these middle permian rocks may be the coolest water deposits in the sverdrup basin the faunas are still part of a boreal arctic province with strong ties to cool water faunas of uralian basin the succession ends with late permian biosiliceous spiculitic cherts containing accessory heterozoan components brachiopods bryozoans and few crinoids these sediments in part coeval with evaporites and terrestrial red beds on the eastern european platform are interpreted to reflect a combination of cool waters elevated nutrients and mid latitude storminess

tropical cyclone activity and western north atlantic stratification over the last millennium a comparative review with viable connections tropical cyclones tc are recognized to modify the thermal structure of the upper ocean through the process of vertical mixing assessing the role this mixing plays in the overall stratification of the upper ocean is difficult due to the relatively short and incomplete instrumental record proxy records for both tc landfalls and oceanographic stratification are preserved within the geological record and provide insight for how past changes in tc induced mixing have potentially affected water column structure prior to the instrumental record here we provide the first comparison between previously published paleo reconstructions of vertical ocean density and tropical cyclone activity from the western north atlantic a prominent lull in tc activity has been observed prior to approximately 1700 ce that extends back several centuries this interval of low tc activity is shown to be concurrent with the timing of increased ocean stratification near great bahama bank potentially due in part to reduced tc induced mixing to test whether this relationship is feasible we present numerical results from a coarse resolution ocean general circulation model experiment isolating the effect of tc surface wind forcing on the upper ocean an anomaly of roughly 0 12 kg m 3 in vertical stratification occurs above and below the mixed layer for model runs with and without tc mixing this anomaly is roughly 25 of the entire paleo density signal observed just prior to 1700 ce these results suggest that tc mixing alone cannot completely explain the density anomaly observed prior to 1700 ce but support tc variability as an important contributor to enhancing oceanic stratification during this interval copyright 2011 john wiley sons ltd

new records of atlantic hurricanes from spanish documentary sources 1 spanish historical documents from the archivo general de indias general archive of the indies have been used to identify caribbean hurricanes and storms from the sixteenth to the nineteenth centuries these sources provide previously unrecorded information on hurricanes useful to complete preexisting chronologies and cyclone tracks our work adds 10 hurricanes not previously identified which can now be freely accessed through the world wide web the results suggest that the seventeenth century may have been less active than the sixteenth and eighteenth centuries with the most active period occurring between 1766 and 1780 additionally the study is the first compilation of information about storms different from hurricanes in the caribbean basin

the permian biostratigraphy of the kolyma omolon region northeast asia the main features of the tectonics permian paleogeography biota structural facies zonation of the kolyma omolon region are analysed the characteristics of the permian regional stratigraphic scale of the kolyma omolon region are described the permian deposits of the kolyma omolon region are divided into four regional stratigraphic subdivisions ranked as superhorizons which in turn are subdivided into nine horizons these horizons are further subdivided into 18 provincial zones lones in accordance with russian stratigraphical nomenclature most of the lones distinguished have dual index species representing the dominant brachiopod and bivalve species the chosen nominal species of these lones are as a rule related to each other phylogenetically and as such they represent key stages in the evolution of their respective taxonomic groups through the permian the resultant biostratigraphic scale is adopted as a regional one for the kolyma omolon chukotka and southeastern part of the verkhoyan okhotsk regions almost all the lones distinguished can also be recognized in the verkhoyansk region and many of the lones are also traceable outside northeast asia q 2006 elsevier ltd all rights reserved

eastern pacific sea surface temperature since 1600 a d the δ18o record of climate variability in galapagos corals we measured stable oxygen isotope ratios and skeletal growth rates in the massive corals pavona clavus and p gigantea from the west coast of isabela island galapagos to assess interannual to decadal climate variability in the eastern pacific comparisons of instrumental data sets show that sea surface temperatures sst in the galapagos region are representative of a broad portion of the eastern equatorial pacific the site is especially well suited for long term studies of the el nino southern oscillation enso phenomenon as it lies within the eastern pacific center of action for thermal anomalies associated with enso the p gigantea isotope record is nearly monthly in resolution spans the period 1961 1982 and shows strong correlation with a galapagos instrumental sst record r 0 90 for annual averages cross spectral analysis shows that sst can explain greater than 80 of the variance in 18o at both the annual cycle and within the high frequency portion of the enso band 3 5 years the p clavus record is annual in resolution extends from 1587 to 1953 a d and was obtained from a 10 m diameter colony preserved within the urvina bay uplift because seawater 18o variations in the region are very small we interpret the urvina bay coral 18o record in terms of annual average sst the isotopic record appears to be a very good but not perfect indicator of enso events and shows good correspondence with the historical enso reconstruction of quinn et al 1987 a number of low 18o excursions that we observe during the 17th and 18th centuries very likely represent enso events that are missing from the historical tabulations most interannual 18o variations between 1607 and 1953 a d represent annual average temperature excursions of 1 to 2 5 c during the little ice age the annual 18o series correlates well with many north american tree ring records and shows low temperatures during the early 1600s and early 1800s and relatively warmer conditions during the 1700s unlike most northern hemisphere tree ring and instrumental records we see no evidence at this site for warming between 1880 and 1940 but rather observe a slight cooling 28 of the total variance the main enso mode is centered at 4 6 years and accounts for 12 of the total variance additional significant oscillations occur at periods of 3 3 6 8 11 17 22 and 34 years both annual growth rate and 18o show variance at periods equivalent to the solar and solar magnetic periods e g 11 and 22 years respectively in addition the amplitude of the 11 year 18o cycle generally varies with the amplitude of the solar cycle supporting previous suggestions that the solar cycle may modulate interannual to decadal climate variability in the tropics the dominant oscillatory modes both within the enso and interdecadal frequency bands shift to shorter periods from the early to middle 1700s and again from the middle to late 1800s this may reflect major reorganizations within the tropical ocean atmosphere system and suggests that tropical pacific climate variability is linked across timescales ranging from years to decades

early opening history of the north atlantic i structure and origin of the faeroe shetland escarpment summary marine geophysical surveys show that the escarpment is the buried feather edge of a thick pile of flood basalts of early eocene age overlying a thinner more widespread layer of basalts of late palaeocene age the escarpment does not therefore define the continent ocean boundary in the southern norwegian sea but instead marks the contemporary shoreline separating terrestrially erupted basalt flows in the north from a restricted shallow water shelf to the south the basalts overlie 5 6 km of mesozoic sediments which have completely buried a large conical flat topped seamount of similar dimensions to anton dohrn and rosemary bank we call this newly postulated body the brendan seamount the mesozoic sediments are at least as old as early cretaceous in age therefore precluding the possibility that the mid cretaceous seafloor spreading episode supposed by some to have created the rockall trough could have also created the thin crust inferred to underlie the faeroe shetland trough and mbre basin

episodic volcanism during break up of the north atlantic evidence from the east greenland plateau basalts abstract the lower tertiary upper paleocene lower eocene plateau basalts in the scoresby sund region of east greenland formed during three distinct magmatic episodes the activity of the first episode was centred in the present inland areas to the northwest and produced a voluminous regional basalt sequence lower sequence the activity of the second episode was centred to the southeast offshore the present atlantic coast and this also produced a voluminous regional basalt sequence upper sequence the third episode was centred on the atlantic coast and gave rise to a dense coastal dyke swarm and local lavas which are now only locally preserved by downfaulting the lavas are all tholeiitic basalts after an initial phase the two regional lava sequences of the first and second episodes show a similar vertical compositional zonation pattern a thin lower formation with variable composition is followed by a thick uniform formation which shows systematic compositional change with height from tio2 rich feti basalts to tio2 poor basalts and ending with a reversal to tio2 rich basalts each of these cyclic patterns apparently resulted from a temporary rifting episode and much of the compositional variation found can be explained by magma development in open magma chambers the dykes and lavas of the third episode of activity have chemical affinities to ocean floor basalts and their tio2 p2o5 ratios indicate formation at a spreading ridge centre the pattern of two failed rifting episodes and one event that produced oceanic crust can be correlated with stages in the complicated initiation of seafloor spreading in the region and the volcanism itself is closely related to this process

development and application of a pollen based paleohydrologic reconstruction from the lower roanoke river basin north carolina usa we used pollen assemblages to reconstruct late holocene paleohydrologic patterns in floodplain deposits from the lower roanoke river basin north carolina southeastern usa using 120 surface samples from 38 transects we documented statistical relationships between pollen assemblages vegetation and landforms backswamp pollen assemblages long hydroperiods are dominated by nyssa tupelo and taxodium cypress and have high pollen concentrations sediments from elevated levees and seasonally flooded forests shorter hydroperiods are characterized by dominant pinus pine pollen variable abundance of hardwood taxa and low pollen concentrations we apply the calibration data set to interpret past vegetation and paleohydrology pollen from a radiocarbon dated sediment core collected in a tupelo cypress backswamp indicates centennial scale fluctuations in forest composition during the last 2400 years backswamp vegetation has occupied the site since land clearance began 300 years ago recent dam empl

volcanic ash in a cored borehole w of the shetland islands evidence for selandian late palaeocene volcanism in the faeroes region

mafic volcaniclastic deposits in flood basalt provinces a review flood volcanic provinces are assumed generally to consist exclusively of thick lavas and shallow intrusive rocks mostly sills with any pyroclastic rocks limited to silicic compositions however mafic volcaniclastic deposits mvds exist in many provinces and the eruptions that formed such deposits are potentially meaningful in terms of potential atmospheric impacts and links with mass extinctions the province where mvds are the most voluminous the siberian traps is also the one temporally associated with the greatest phanerozoic mass extinction a lot remains to be learned about these deposits and eruptions before a convincing genetic link can be established but as a first step this contribution reviews in some detail the current knowledge on mvds for the provinces in which they are better known i e the north atlantic igneous province including greenland the faeroe islands the british isles and tephra layers in the north sea basin and vicinity the ontong java plateau the ferrar and the karoo we also provide a brief overview of what is known about mvds in other provinces such as the columbia river basalts the afro arabian province the deccan traps the siberian traps the emeishan and an archean example from australia the thickest accumulations of mvds occur in flood basalt provinces where they underlie the lava pile faeroes n1 km ferrar province z400 m siberian traps 700 m in the faeroes case the great thickness of mvds can be attributed to accumulation in a local sedimentary basin but in the ferrar and siberian provinces the deposits are widespread n310 5 km 2 for the latter on the ontong java plateau over 300 m of mvds occur in one drill hole without any overlying lavas where the volcaniclastic deposits are sandwiched between lavas their thickness is much less in most of the cases reviewed primary mvds are predominantly of phreatomagmatic origin as indicated by the clast assemblage generally consisting of basaltic clasts of variable vesicularity dominantly non to poorly vesicular mixed with abundant country rock debris the accidental lithic components often include loose quartz particles derived from poorly consolidated sandstones in underlying sedimentary basins east greenland ferrar karoo these underlying sediments or sedimentary rocks were not only a source for debris but also aquifers that supplied water to fuel phreatomagmatic activity in the

mangrove dynamics in the southwestern caribbean since the little ice age a history of human and natural disturbances relatively little is known about the long term response of caribbean mangroves to human and natural disturbances during the little ice age lia we present new palynological information on the dynamics of the bahia honda mangrove from the eastern coast of san andres island in the southwestern caribbean for the late holocene major changes in the bahia honda pollen record show the combined effects of natural events strong storms and sea level rise and human disturbances these changes are supported by 14c dates sedimentological and palynological information a storm most probably a hurricane was recorded around ad 1600 caused sediment reworking and the subsequent loss of about 2000 years of the vegetation record the devastation of tree vegetation by this event allowed the expansion of heliophytic vegetation e g grasses and vines mangroves and coastal vegetation started to recover at ad 1700 reaching their maximum extent within a few decades when microforaminifera shells became abundant at

a tree ring based reconstruction of the atlantic multidecadal oscillation since 1567 a d 1 we present a tree ring based reconstruction of the atlantic multidecadal oscillation amo which demonstrates that strong low frequency 60 100 yr variability in basin wide 0 70 n sea surface temperatures ssts has been a consistent feature of north atlantic climate for the past five centuries intervention analysis of reconstructed amo indicates that 20th century modes were similar to those in the preceding 350 yr and wavelet spectra show robust multidecadal oscillations throughout the reconstruction though the exact relationships between low frequency sst modes higher frequency 7 25 yr atmospheric modes e g north atlantic oscillation arctic oscillation and terrestrial climates must still be resolved our results confirm that the amo should be considered in assessments of past and future northern hemisphere climates

lateglacial and holocene palaeohydrology in the western mediterranean region the lake estanya record ne spain abstract the multi proxy analysis of sediment cores recovered in karstic lake estanya 42 02 n 0 32 e 670 m a s l ne spain located in the transitional area between the humid pyrenees and the semi arid central ebro basin provides the first high resolution continuous sedimentary record in the region extending back the last 21 000 years the integration of sedimentary facies elemental and isotopical geochemistry and biogenic silica together with a robust age model based on 17 ams radiocarbon dates enables precise reconstruction of the main hydrological and environmental changes in the region during the last deglaciation arid conditions represented by shallow lake levels predominantly saline waters and reduced organic productivity occurred throughout the last glacial maximum 21 18 cal kyrs bp and the lateglacial reaching their maximum intensity during the period 18 14 5 cal kyrs bp including heinrich event 1 and the younger dryas 12 9 11 6 cal kyrs bp less saline conditions characterized the 14 5 12 6 cal kyrs bp period suggesting higher effective moisture during the bolling allerod the onset of more humid conditions started at 9 4 cal kyrs indicating a delayed hydrological response to the onset of the holocene which is also documented in several sites of the mediterranean basin higher although fluctuating holocene lake levels were punctuated by a mid holocene arid period between 4 8 and 4 0 cal kyrs bp a major lake level rise occurred at 1 2 cal kyrs bp conducive to the establishment of conditions similar to the present and interrupted by a last major water level drop occurring around 800 cal yrs bp which coincides with the medieval climate anomaly the main hydrological stages in lake estanya are in phase with most western mediterranean and north atlantic continental and marine records but our results also show similarities with other iberian and northern african reconstructions emphasizing peculiarities of palaeohydrological evolution of the iberian peninsula during the last deglaciation

discovery of shallow marine biofacies conodonts in a bioherm within the carboniferous permian transition in the omolon massif ne russia near the north paleo pole correlation with a warming spike in the southern hemisphere the conodont genera hindeodus and streptognathodus are reported for the first time within the carboniferous permian transition in the northern high latitudes of the paren river omolon massif ne russia several fossil groups including brachiopods bivalves scaphopods and microgastropods were found to be prolific in the invertebrate dominated bioherms these bioherms occur within predominantly siliciclastic sequences with extremely poor fauna whereas in the studied bioherms the diversity of the bivalves and brachiopods exceeded observed diversity elsewhere in coeval facies in ne russia the bioherms are biostratigraphically constrained as uppermost pennsylvanian to lowermost cisuralian based on ammonoids the very unusual peak of bivalve and brachiopod diversity and the occurrence of conodonts that require minimum sea water temperatures of at least 10 12 c indicate a short lived but significant warming event at that time at least of provincial significance this event most likely corresponds with a short lived warming event recently discovered in the east of the southern hemisphere in timor and australia thus the event is possibly of global significance

600 year sedimentary archive of hurricane strikes in a prograding beach ridge plain southwestern louisiana abstract this study tests a novel approach to paleotempestology substituting the lateral time depth of a prograding beach ridge plain for the vertical time depth of an aggrading coastal lake pond lagoon swamp or marsh trenching and coring of a beach ridge plain in southwestern louisiana revealed six sand beds and one shell bed interpreted as hurricane washover deposits the sand beds are readily distinguished from enclosing marsh sediments by their higher sand content lower organic content and contrasting microfossil assemblages based on the modern analogs of hurricanes audrey 1957 rita 2005 and ike 2008 and consideration of nearby landfalling hurricanes in the historical record it was determined that the storm intensity threshold of the study site is equivalent to a category 3 hurricane there is a wide variation in hurricane strike frequency between this site and other sites bordering the gulf of mexico this variation results from differences in site sensitivity and the nature of geologic or geochemical proxies used to derive hurricane strike records the approach demonstrated by this study could have applicability at other sites around the world where beach ridge plains are subject to tropical cyclone strikes

nannoplankton zonation and the palaeocene eocene boundary beds of nw europe an indirect correlation by means of volcanic ash layers correlation of early palaeogene ash layers in dsdp hole 550 leg 80 goban spur with those of the north sea basin indicates that the base of nannoplankton zone np10 approximates the base of the sele formation of the north sea area the bases of the danish ash series the german ash bearing untereozan 1 and the paris basin sparnacian and the top of the woolwich reading bottom bed of the london basin if as is now common practice the palaeocene eocene boundary is placed at the np9 np10 boundary then the units listed above would constitute the basal units of the eocene in their respective countries the cessation of large scale pyroclastic activity took place at about the middle of the zone np10 interval

high resolution palaeoclimatology of the last millennium a review of current status and future prospects this review of late holocene palaeoclimatology represents the results from a pages clivar intersection panel meeting that took place in june 2006 the review is in three parts the principal high resolution proxy disciplines trees corals ice cores and documentary evidence emphasizing current issues in their use for climate reconstruction the various approaches that have been adopted to combine multiple climate proxy records to provide estimates of past annual to decadal timescale northern hemisphere surface temperatures and other climate variables such as large scale circulation indices and the forcing histories used in climate model simulations of the past millennium we discuss the need to develop a framework through which current and new approaches to interpreting these proxy data may be rigorously assessed using pseudo proxies derived from climate model runs where the answer is known the article concludes with a list of recommendations first more raw proxy data are required from the diverse disciplines and from more locations as well as replication for all proxy sources of the basic raw measurements to improve absolute dating and to better distinguish the proxy climate signal from noise second more effort is required to improve the understanding of what individual proxies respond to supported by more site measurements and process studies these activities should also be mindful of the correlation structure of instrumental data indicating which adjacent proxy records ought to be in agreement and which not third large scale climate reconstructions should be attempted using a wide variety of techniques emphasizing those for which quantified errors can be estimated at specified timescales fourth a greater use of climate model simulations is needed to guide the choice of reconstruction techniques the pseudo proxy concept and possibly help determine where given limited resources future sampling should be concentrated

reconstruction of prehistoric landfall frequencies of catastrophic hurricanes in northwestern florida from lake sediment records abstract sediment cores from western lake provide a 7000 yr record of coastal environmental changes and catastrophic hurricane landfalls along the gulf coast of the florida panhandle using hurricane opal as a modern analog we infer that overwash sand layers occurring near the center of the lake were caused by catastrophic hurricanes of category 4 or 5 intensity few catastrophic hurricanes struck the western lake area during two quiescent periods 3400 5000 and 0 1000 14 c yr b p the landfall probabilities increased dramatically to ca 0 5 per yr during an hyperactive period from 1000 3400 14 c yr b p especially in the first millennium a d the millennial scale variability in catastrophic hurricane landfalls along the gulf coast is probably controlled by shifts in the position of the jet stream and the bermuda high

the permian of the verkhoyansk okhotsk region ne russia abstract this report summarizes data on the permian deposits of the verkhoyansk okhotsk region tectonics paleogeography fauna flora and stratigraphy the verkhoyansk okhotsk region covers the area of the verkhoyansk fold and thrust belt the permian deposits of this region were formed on the passive continental margin of the angarida continent the ancient siberian continent situated within the siberian platform this continental margin developed as the result of continental break up in the late precambrian late precambrian to jurassic including permian sediments were deposited on a passive margin with a continental shelf extending out into an ocean towards the northeast during the permian exclusively terrigenous sediments were deposited over a vast territory in the verkhoyansk paleobasin forming part of this continental margin the permian deposits are divided into six regional stratigraphic units ranked as horizons regional stages which in turn are subdivided into faunal zones and beds serving as the basis for intra regional correlation in the late jurassic cretaceous the continental margin sediments were converted into a foreland fold and thrust belt due to the collision of the siberian platform with the kolyma omolon and okhotsk continental blocks

holocene palaeohydrology and climate variability in northeastern spain the sedimentary record of lake estanya pre pyrenean range abstract this multi proxy study of sediment cores from karstic lake estanya pre pyrenean range ne spain provides the first complete continuous record of the hydrological evolution in the northeastern iberian peninsula over the last 9500 yr six sedimentary facies and four main sedimentary units have been defined after integration of sedimentological mineralogical and geochemical analyses the use of total sulphur content and sedimentary facies as paleohydrological proxies allows reconstruction of relative changes in lake level the estanya record shows a large increase in water availability after 9 2 ka fluctuating lake levels and salinity during the period 9 2 4 2 ka and generally higher lake levels after 1 7 ka periods of increased run off and sediment delivery and less saline conditions occurred at 8 5 8 2 6 7 5 9 and 4 9 4 2 ka dominant lower lake levels and concentrated waters during the period 4 2 0 8 ka were punctuated by a higher lake level higher clastic input episode ca 1 7 1 ka fluctuating but higher lake levels occurred during the last 800 years the main hydrological phases in lake estanya are coherent with western mediterranean and north atlantic holocene reconstructions but they also show similarities with northern african records

paleogene magnetic stratigraphy in umbrian pelagic carbonate rocks the contessa sections gubbio the umbrian sequence of pelagic carbonate rocks provides an opportunity for precise correlation between paleogene biostratigraphy and geomagnetic polarity history the red to pink paleocene to middle eocene scaglia rossa limestone the varicolored upper eocene scaglia variegata limestone and the gray green oligocene scaglia cinerea marlstone form a 250 m thick continuous exposure in the contessa valley near gubbio italy magnetostratigraphic lithostratigraphic and biostratigraphic investigations in three sections covering the entire paleogene have confirmed and dated the geomagnetic reversal sequence for most of this period the ferromagnetic mineral in the scaglia cinerea is magnetite and af demagnetization to peak fields of 20 mt is sufficient to define the characteristic remanent magnetization the scaglia variegata and pink scaglia rossa samples contain an additional hematite component which is very pronounced in dark red paleocene scaglia rossa samples changes of magnetic mineralogy take place in these limestones during heating especially above 500 c however thermal demagnetization is effective in isolating the characteristic remanence vectors which form almost antipodal clusters of directions representing normal and reversed polarities the directions are rotated counterclockwise partly due to post oligocene tectonism paleontological zonations of planktic foraminifera and calcareous nannofossils were hampered by poor preservation but the major epoch and stage 29 as in the gubbio bottaccione section paleocene eocene just above anomaly 25 eocene oligocene between anomalies 13 and 15 oligocene miocene just below anomaly 6c these correlations require slight modifications to previous conclusions on paleogene sea floor spreading rates

climatic implications from the sequential changes in diversity and biogeographic affinities for brachiopods and bivalves in the permian of eastern australia and new zealand abstract brachiopoda and bivalvia of successive macro invertebrate zones of eastern australia and new zealand are analysed to demonstrate a sequence of climatic change throughout the permian period reflecting glacial episodes separated by warmer intervals three such glacial intervals are indicated for the early cisuralian permian a long asselian episode a brief artinskian episode and a substantial kungurian interval followed by a cold roadian interval middle permian guadalupian and a very late permian lopingian episode markedly warmer intervals developed in the possibly late asselian baigendzinian and much of the lopingian in addition relatively long cool times allowed the flourishing and comparative diversification of eastern australian faunas at several stages

permian ammonoid associations of the verkhoyansk region northeast russia abstract on the basis of a study of the majority of permian ammonoids known in verkhoyansk region and an analysis of their age distribution seven associations and four subassociations are established these ammonoid associations are the khorokyt arkachan endybal mysovy orol takamkyt delendzha and post sverdrupites associations in ascending order the majority of these associations and subassociations include some complementary ammonoid beds the ammonoid associations and subassociations are considered as biostratigraphic divisions of regional stratigraphic extent and are useful for dating and correlating the permian sedimentary sequences of the verkhoyansk region the geographical and stratigraphic distributions of 360 permian ammonoid shells in the verkhoyansk region permits us to not only diagnose each ammonoid association with specific index species but also to elucidate the biogeographic connections and migration patterns of the verkhoyansk ammonoid faunas in relation to these spreading throughout the entire boreal realm

high velocity breakup related sills in the voring basin off norway multichannel seismic reflection profiles in the hel graben v0ring basin reveal a sill complex at approximately 5 km depth it is associated with exceptionally high 7 4 km s 1 seismic wide angle velocities the existence of observable wide angle arrivals shows that the sills act as efficient waveguides seismic reflection data and amplitude modeling constrain the thickness of individual sills to approximately 100 m sonic logs from sills of similar thickness on the nearby utgard high show an average velocity of 7 0 km s 1 such high velocities require an olivine gabbroic sill composition and emplacement under conditions which allowed growth of relatively large crystal sizes a possible reason for such an emplacement environment is the hei graben s role as an intrusion center during breakup volcanism this would provide the necessary duration of the magmatic activity as well as locally increased melt volumes and cooling times sill complexes of this kind decrease the accuracy of determined velocity fields and crustal geometries below the top of the sill complex affecting depth conversion and gravity modeling furthermore the results question the concept of lower crustal bodies as large scale homogeneous accumulations of mafic melt