deposit from a giant wave on the island of lanai hawaii limestone bearing gravel the newly named hulopoe gravel blankets the coastal slopes on lanai the deposit which reaches a maximum altitude of 326 meters formerly was believed to have been deposited along several different ancient marine strandlines but dated submerged coral reefs and tide gauge measurements indicate that the southeastern hawaiian islands sink so fast that former worldwide high stands of the sea now lie beneath local sea level evidence indicates that the hulopoe gravel and similar deposits on nearby islands were deposited during the pleistocene by a giant wave generated by a submarine landslide on a sea scarp south of lanai

stratigraphic responses to a major tectonic event in a foreland basin the ecuadorian oriente basin from eocene to oligocene times the eocene to oligocene sediments of the ecuadorian oriente basin record two kinds of second order stratigraphic response to the tectonic evolution lower eocene shows evidences of local scale syntectonic deposits this tectonic activity can be related to right lateral convergent movements inverting pre cretaceous extensional structures upper eocene and oligocene sediments are integrated as the expression of an isostatic rebound characterizing a basin scale syntectonic deposition this response is evidenced by a reciprocal architecture of the depositional sequences identified in the sedimentary formations these data have allowed us to propose a new geodynamic model for the paleogene evolution of the oriente basin

boulders of mis 5 age deposited by a tsunami on the coast of otago new zealand abstract a series of elevated imbricated boulders were investigated on the otago coastline southeast new zealand through field surveying and optical luminescence dating by using established hydrodynamic relationships of sediment transport the energy required to move the clasts was calculated and compared to the historic record of marine inundations of that coast the boulders are platy in shape and are over 2 m long in some cases and are sourced from a locally outcropping conglomerate unit which appears to be the only lithology on this section of coast that erodes to produce clasts of this size it is estimated that the boulders were deposited by a tsunami between 2 and 3 m high during the latter part of marine isotope stage 5 they therefore represent the first pre holocene tsunami deposit and one composed of large boulders described on the new zealand coastline

modelling the processes of cliff top erosion and deposition under extreme storm waves at exposed sites on the deep water coasts of the british isles cliff top storm deposits ctsds occur on cliffs at a variety of elevations above sea level and may occasionally reach up to 50 m above sea level time series field mapping of ctsds has demonstrated their formation over the historical period and their continued modification during major past storms this paper seeks to clarify the morphogenetic context of ctsds model the wave conditions and forces encountered at the cliff face and cliff top platform and propose mechanisms to link wave processes to cliff face quarrying and landwards cliff top transport of quarried blocks to deposition zones at the rear of the cliff top platform we report on wave tank experiments using scaled cliff and wave conditions from a cliff in the shetland islands to focus on three situations incident waves lower than the cliff edge height at the same height as the cliff edge height and higher than the cliff edge height the modelling suggests that steep waves of 10 m and above impacting on a 15 m high cliff will result in impact pressures sufficient to promote crack propagation block detachment and lifting of large blocks large but not necessarily steep waves of the same height as the cliff edge produce sufficient impact pressures and water flow over the cliff edge and platform to entrain blocks transport and deposit them on the cliff top where cliff top height is below wave crest elevation green water bore flow occurs sufficient to force rotation or lifting of blocks out of cliff top and cliff top platform sockets high flow velocities rapidly accelerate and transport blocks inland until the flow attenuation results in deposition of blocks at the limit of run up the model results provide a good explanatory framework to account for the quarrying of the upper part of the cliff face and cliff top platform under storm wave conditions and provide an insight into the exceptional velocities experienced over the cliff top platform under bore flow conditions the modelling results show that extreme storm waves are capable of quarrying transporting and depositing large blocks at altitude and significant distances inland and so present serious questions about the use of such deposits as diagnostic of palaeo tsunami

an environmental reconstruction of the palaeo amazon river system middle late miocene nw amazonia abstract new sedimentological and palynological data from the tertiary sediments in the upper amazon river area suggest that these sediments are fluvio lacustrine deposits of middle to late miocene age they were generated as a result of the uplift of the eastern cordillera andes and constitute possibly the oldest relics of the amazon river system the palaeoenvironment in which these sediments were deposited is characterized by extensive wetlands environments formed by swamps shallow lakes crevasse splay channels and crevasse delta lakes where the channel environment is poorly represented the palaeovegetation was dominated by palms e g mauritia and grimsdalea riverine taxa e g bombacaceae amanoa and alchornea ferns and fern allies e g polypodiaceae and selaginellaceae floating meadows gramineae and aquatic taxa ceratopteris botryococcus and azolla the relative abundance of gramineae and the occurrence of andean type pollen taxa is related to the andean origin of the fluvial system the varzeas of the present upper amazon river flood basin are probably the best analogue for the middle to late miocene environment intervals rich in marine palynomorphs mangrove pollen brackish tolerant molluscs and ostracods and ichnofossils of the thalassinoides teichichnus association suggest that the palaeoenvironment was characterized by brackish conditions and marine influence these marine incursions are possibly related to the langhian and the serravallian global sea level rise although in the middle miocene a global cooling is known to have occurred no indicators of a cooler climate have been observed in the miocene palynoflora of the upper amazon river area finally four new sporomorph species are described belonging to the form genera psilatriletes clavainaperturites and psilaperiporites

isotopic paleontologic and ichnologic evidence for late miocene pulses of marine incursions in the central andes recognition of an inferred miocene marine incursion affecting areas from colombia through peru and bolivia and into argentina is essential to delineate the south american seaway in bolivia corresponding strata of inferred marine origin have been assigned to the late miocene yecua formation we carried out high resolution 13 c and 18 o isotopic studies on 135 in situ carbonates from 3 outcrops combined with detailed sedimentologic paleontologic and ichnologic analysis four less negative 13 c excursion levels were recorded that coincide well with beds containing marine body barnacle and trace ophiomorpha fossils these strata are interbedded with red green beds containing mudcracks plant roots gypsum and trace fossils of the continental scoyenia ichnofacies our data are significant in that they show for the first time four possible short lived marine incursions in the bolivian central andes during the late miocene the result is constrained by a new u pb date of 7 17 0 34 ma at the top of yecua strata

boulders transport by catastrophic waves along the ionian coast of apulia southern italy abstract several tracts of the ionian coast of apulia southern italy are characterized by large boulders up to 80 t in weight scattered some meters above present sea level the largest boulder is about 80 t in weight and slid for about 40 m from the mean sea level up to about 1 8 m of altitude elongated boulders show a remarkably narrow range of orientation of the long axis as well as of the imbrication axis suggesting that they had been transported by a single catastrophic event most likely a tsunami connected to a wave train approaching the coast from the south stratigraphic morphological and historical data suggest that this event occurred during the late holocene conventional radiocarbon age determination performed on lithophag shells collected from a large boulder yielded a calibrated age between 1421 and 1568 a d then the catastrophic wave train probably a tsunami could be a local effect of the strong earthquake which hit southern italy on december 5th 1456

numerical analysis of boulder transport by the 2004 indian ocean tsunami at pakarang cape thailand at pakarang cape thailand we conducted field observations and numerical modeling of the spatial and grain size distributions and sources of boulders deposited by the 2004 indian ocean tsunami the boulders are a very rare example of boulders for which a tsunami origin is well confirmed numerical modeling of the tsunami s boulder transport revealed that the grain size and spatial distributions of boulders are explainable by the initial distribution of boulders at the source and the tsunami s local behavior which is controlled strongly by the tsunami hydrodynamic features and local topography soon after the bore front reached at the beach the tsunami s hydraulic force on the tidal bench decreased suddenly below the critical force necessary to displace the boulder because of the seaward propagation of the reflected wave that had been generated at the beach slope consequently all boulders were deposited below the high tide line and subsequently concentrated at the western coast of the cape absence of boulders that had been originally deposited deeper than 10 m water depth is also explained by this reflected wave because the wave passed over boulders that had been originally deposited at 10 m water depth before the boulder crossed the reef edge our well tuned model elucidates how the tsunami was able to deposit large boulders on the tidal bench at the cape the results demonstrate that theoretically up to 250 tons of boulders might have been emplaced on the tidal bench by the 2004 indian ocean tsunami at the cape approximately 7 m wave height the calculated maximum weight is of comparable order to that of boulders around the world that are inferred to be of tsunami origin although we infer that the weight is determined based on the sensitive balance of the local topography hydrodynamic features of the tsunami and the initial distribution of boulders at the source

boulder deposits from large waves during the last interglaciation on north eleuthera island bahamas abstract seven boulders measuring 100 to 1000 m 3 are scattered along the coastal ridge of north eleuthera some are situated on ridge crests up to 20 m above present sea level the boulders were probably deposited during oxygen isotope substage 5e or 5d as shown by their stratigraphic setting and by amino acid racemization ratios d alloisoleucine l isoleucine ratios were determined for land snails and oolite of both marine and eolian origin was associated with the boulders like the boulders the probable source rocks exposed in the adjacent cliffs are composed of marine and eolian limestone of oolitic and peloidal composition the source beds are correlated with stage 9 or 11 the largest boulder is about 10 times the size of the largest holocene ones moved by waves in the area tsunamis are a reasonable possibility as a transporting mechanism of the pleistocene boulders however if deposited instead by storms during the last interglaciation the storms were of much greater intensity than those occurring in the region during the late holocene

chevron ridges and runup deposits in the bahamas from storms late in oxygen isotope substage 5e abstract landward pointing v shaped sand ridges several kilometers long are common along the windward margin of the bahama islands their axes share a northeast southwest trend internally the ridges contain low angle oolitic beds with few erosional truncations commonly interbedded are tabular fenestrae rich beds such as those formed by the sheet flow of water over dry sand defined here as chevron ridges these landforms appear to have originated in the rapid remobilization of bank margin ooid bodies by the action of long period waves from a northeasterly source deposits along adjacent coastlines also preserve evidence of the impact of large waves reworked eolian sand bodies preserve beach fenestrae and hydraulic scour traces up to 40 m on older ridges on cliffed coasts 1000 ton boulders have been thrown well inland recording the impact of large waves amino acid ratios confirm a correlation of the ridges across the archipelago while stratigraphy spacing and cross cutting relationships indicate emplacement as sea level fell rapidly from the substage 5e maximum at or above 6 m

a 60 million year cenozoic history of western amazonian ecosystems in contamana eastern peru abstract we provide a synopsis of 60 million years of life history in neotropical lowlands based on a comprehensive survey of the cenozoic deposits along the quebrada cachiyacu near contamana in peruvian amazonia the 34 fossil bearing localities identified have yielded a diversity of fossil remains including vertebrates mollusks arthropods plant fossils and microorganisms ranging from the early paleocene to the late miocene pliocene 20 successive levels this cenozoic series includes the base of the huchpayacu formation fm early paleocene lacustrine fluvial environments charophyte dominated assemblage the pozo fm middle late eocene marine then freshwater environments most diversified biomes and complete sections for the chambira fm late oligocene late early miocene freshwater environments vertebrate dominated faunas the pebas fm late early to early late miocene freshwater environments with an increasing marine influence excellent fossil record and ipururo fm late miocene pliocene fully fluvial environments virtually no fossils preserved at least 485 fossil species are recognized in the contamana area 250 plants 212 animals and 23 foraminifera based on taxonomic lists from each stratigraphic interval high level taxonomic diversity remained fairly constant throughout the middle eocene miocene interval 8 12 classes ordinal diversity fluctuated to a greater degree and family species diversity generally declined with a drastic drop in the early miocene the paleocene pliocene fossil assemblages from contamana attest at least to four biogeographic histories inherited from i mesozoic gondwanan times ii the panamerican realm prior to iii the time of south america s cenozoic splendid isolation and iv neotropical ecosystems in the americas no direct evidence of any north american terrestrial immigrant has yet been recognized in the miocene record at contamana

boulders as a signature of storms on rock coasts this paper is the first review of coastal boulder studies it serves as a peer reviewed introduction to a special issue on the topic of boulders as a signature of storms on rock coasts since 2004 and the indian ocean tsunami most coastal boulder research has been focused on using boulders as sedimentary signatures of palaeo tsunami events and the most commonly used transport equations typically suggest that large boulder deposits are products of tsunami rather than storms there is growing empirical evidence demonstrating on inter annual to century timescales that storm waves are capable of transporting and depositing boulders of significant size at elevations well above sea level current process studies of how boulders are eroded transported and deposited have not received wide attention by rock coast geomorphologists or palaeoenvironmental reconstruction scientists this special issue is framed around the goal of highlighting our current understanding of the role of storm waves as a driving mechanism for boulder erosion transport and deposition here we review the current state of knowledge about boulder dynamics boulder responses to storms and boulders as sedimentary signatures of storm events we identify gaps in our conceptual and quantitative understanding lastly we propose means of addressing research gaps improving consistency between researchers and collecting multi purpose data this review and the papers contained within the special issue provide an improved understanding of coastal dynamics particularly the role storms can play in influencing erosion rates and depositional patterns of coarse material i e boulders or larger which has hitherto been under represented in the literature

rocks of ages propagation of hot rock cookery in western north america cook stone technology s old world roots were established by 30 000 b p and reappeared in the new world by 10 000 b p after millennia of direct fire cooking hot rock cookery which is necessary for foods that require prolonged cooking facilitated land use intensification by affording greater utilization of nutrients in available foods on a given landscape this technology gradually diversified during the early holocene in western north america by 4000 b p its initial intensification was underway final intensification began by 2000 b p and typically peaked during the last 1500 years propagation of hot rock cookery exemplifies pre columbian food crises and signals carbohydrate revolutions wherein more high cost foods feed growing populations as modeled cook stone griddles earth ovens and steaming pits with rock heating elements are more costly facilities insofar as fuel is used to heat rocks that in turn extend cooking time and temperature more expensive still is stone boiling given that fuel heats rocks that in turn heat water that cooks the food even more expensive in terms of energy expended is the manufacture of heating elements in the form of stone ceramic and metal cooking containers all of which afford further evidence of land use intensification

marine incursions and the influence of andean tectonics on the miocene depositional history of northwestern amazonia results of a palynostratigraphic study abstract new palynological and sedimentological data permit the age of neogene sediments in northwestern amazonia to be established more precisely and indicate that major environmental changes occurred in the area during this time based on a study of borehole samples the age of the solimoes formation solimoes basin northwestern brazil is determined as miocene and five pollen zones are distinguished which are correlated with existing zonations for northern south america in addition 30 new sporomorphs are described which belong to the following 12 genera psilamonocolpites retimonocolpites retitricolpites retibrevitricolpites psilatriporites nov gen bombacacidites psilatricolporites retitricolporites rugutricolporites psilastephanoporites nov gen psilastephanocolporoties and heterocolpites a correlation is made between the brazilian wells and some of the studied outcrops in colombian and peruvian amazonia based on palynological marker species the presence of coastal elements such as mangroves zonocostites indicates that during the miocene this area was influenced by marginal marine conditions caused by several marine incursions these incursions may be related to global sea level fluctuations miocene marine phases also are known from sites elsewhere in northern south america which at present like northwestern amazonia are entirely ruled by continental conditions sediment composition shows that during the early miocene the guyana shield was the major source area of sediment input in the basins of northwestern amazonia in the interval from early to middle miocene the andes became the major sediment source area the change in provenance is related to the uplift of the eastern cordillera this event caused a major change in palaeoenvironment and palaeogeography in northwestern amazonia which was characterized by the reverse of a northwestward directed fluvial system into an eastward directed fluvial lacustrine system with an estuarine character

cretaceous early paleocene drainage shift of amazonian rivers driven by equatorial atlantic ocean opening and andean uplift as deduced from the provenance of northern peruvian sedimentary rocks huallaga basin abstract the northern part of south america has undergone several major changes in its tectonic setting since the triassic evolving from rifting to the development of a retroarc foreland basin on its andean margin leading to margin extension and continental uplift following the breakup between africa and south america so far it is unclear when and how these geodynamic events affected the paleo amazonian drainage in this study we investigate the provenance of triassic eocene sedimentary rocks deposited in the northern peruvian amazonian basin based on their sr nd isotopic compositions and u pb zircon dating the triassic jurassic samples have end 0 values ranging from 7 9 to 10 0 and main u pb zircon peaks at 0 9 1 3 ga 31 33 and 0 5 0 7 ga 21 28 that suggest a mixed clastic supply from the western and eastern cordillera or craton within a rift to post rift setting samples from the albian maastrichtian interval yield much lower end 0 values 16 8 to 18 6 and a dominance of zircon grains derived from terranes in the easternmost brazilian shield ventuari tapajos 2 0 1 82 ga rio negro jurena 1 82 1 54 ga and rondonia san ignacio 1 54 1 3 ga thus indicating a cratonic source for these sedimentary rocks finally the early paleocene eocene sedimentary rocks record the first arrival of andean detritus in the amazonian retroarc foreland with end 0 values ranging between 5 6 to 12 0 and up to 16 of the zircon grains yielding ages younger than 120 ma together with recently published studies these provenance data document the existence of a long lived aptian maastrichtian continent wide cratonic drainage in the northern part of south america this cratonic drainage developed in response to the late cretaceous uplift of the northeastern part of the south america craton likely driven by geodynamic processes related to post rift opening of the atlantic equatorial ocean the formation of a late maastrichtian early paleocene mountain chain in the peruvian andes associated with the onset of provenance from the andean orogenic belt led to a shift of the amazon drainage pattern hence the earliest andean amazonian rivers are no younger than late maastrichtian early paleocene

a unique 4000 year long geological record of multiple tsunami inundations in the augusta bay eastern sicily italy abstract we present the geological evidence for a 4000 year long record of multiple tsunami inundations along the coast of the augusta bay eastern sicily and discuss its implications the research was carried out through a multi theme approach which benefited from an extraordinarily long historical record that we used to guide detailed geomorphologic and geologic surveys coring campaigns and laboratory analyses two sites named the augusta hospital and priolo reserve were selected and investigated in detail along the 25 km long coastline of augusta bay we found evidence for six possibly seven tsunami deposits three of them may be tentatively associated with the 1693 and 365 ad ionian sea historical tsunamis and the 3600 bp santorini event the other three possibly four deposits are evidence for unknown paleo inundations dated at about 650 770 ad 600 400 bc and 975 800 bc at augusta hospital site and 800 600 bc at priolo reserve site we use these ages to extend further back the historical record of tsunamis available for this coastal area the exceptional number of tsunami deposits found with this study allowed us to derive an average geologic tsunami recurrence interval in the augusta bay of about 600 years for the past 4 ka conversely the historical tsunami data for the past millennium suggest an average tsunami recurrence interval of about 250 years this difference in the average recurrence intervals suggests that only the strongest inundations may leave recognizable geological signatures at the investigated sites i e the evidence for the 1908 and 1169 tsunamis is missing but also that the geomorphological setting of the site and its erosional depositional history are critical aspects for the data recording thus an average recurrence interval derived from the geological record should be considered as a minimum figure the identification and age estimation of tsunami deposits represent a new and independent contribution to tsunami scenarios and modeling for coastal hazard assessment in civil protection applications furthermore our study cases provide new elements on tsunami deposit recognition related to exceptionally large events that occurred in the aegean sea

characteristics and hydrodynamics of boulders transported by storm waves at kudaka island japan abstract this study investigates the size position and the long axis orientation of 210 boulders at kudaka island japan these boulders were deposited from the reef crest to the slope of the back reef moat distributed within 275 m from the reef edge most boulders were rectangular to ellipsoidal without sharp broken edges they are reef rock fragments estimated as

carbon and nitrogen stable isotope analysis of hunter gatherers from the coleman site a late prehistoric cemetery in central texas abstract we report on a stable isotopic analysis of 17 hunter gatherer burials from the coleman site 41bx568 a late prehistoric toyah interval 700 350 years bp occupation in texas prior to our analysis isotopic research on toyah populations in central texas was represented by a single burial at site 41bx677 that burial showed an isotopic pattern suggestive of a diet heavily focused on cam c 4 plants and c 4 fauna coleman burials show a different pattern while interpretations are complicated by high variability in the isotopic signatures of children and by differences in male and female diets possibly related to mate exchange the 11 adult and adolescent burials at coleman show a diet focused on c 3 fauna and the use of both c 3 and cam c 4 plants the moderate cam c 4 plant use is a radical departure from a trend of increasing c 3 plant use that characterized hunter gatherers in this region for at least 6200 years prior to the start of the toyah interval protein sources among coleman adults probably centered on deer but also included high nitrogen 15 n animals such as fish males seem to have differential access to these high nitrogen sources two different isotopic patterns one reflecting a focus on c 3 fauna and moderate use of cam c 4 plants and a second reflecting c 4 fauna and extensive use of cam c 4 plants are represented during toyah while interpretations are complicated by small sample sizes these two patterns could simply reflect temporal differences different acquisition strategies based on availability or hint at different subsistence strategies it may also be the case that the 41bx677 individual represents an immigrant into the central texas region one with a different isotopic history

large boulders along the south eastern ionian coast of sicily storm or tsunami deposits abstract this study investigates the size shape position pre transport setting and long axis orientation of 175 boulders found along the south eastern ionian coast of sicily these megaclasts were deposited by the sea or moved from the same rocky coast to the shore platform and distributed within 60 m of the shoreline most boulders are rectangular to ellipsoidal with sharp broken edges they are calcarenite fragments up to 27 t in mass some of the boulders up to 32 m from shore were observed to have moved after strong winter storms occurring during december 2008 january 2009 whereas the positions of many boulders were unchanged we use wave transport equations jointly with statistical analysis of boulders in order to determine the extreme events geological or meteorological responsible for these singular accumulations using the significant wave height and period of maximum observed storms and historical tsunamis 1693 and 1908 events along the ionian coast of sicily we have estimated the approximate transport distance of boulders by these waves at the coast results show that the largest storm waves were probably responsible for the current distribution of most boulders however since the size and horizontal displacement distance of some boulders scattered randomly along the shoreline at distance 40 m cannot be explained by storm wave action we suggest that they are likely deposited by tsunamis radiocarbon dating performed on three of these anomalous boulders at a distance 40 m from the shoreline gave an age suggesting that two of them were likely deposited by the 1693 or 1908 tsunamis whereas the third was emplaced by a tsunami that occurred after 650 930 a d we show that both wave processes storm and tsunami can deposit boulders we find that the significant difference between storm and tsunami waves is not the breaking wave height but the wave period that influences attenuation and then the flooding distance hence if the boulder transport limit of the largest storm waves in the past at the study area is estimated then it is possible to recognize that the boulders deposited far beyond this limit because of their size and shape were not transported by storm waves but could have been emplaced by waves with longer period such as the tsunamis

cliff top megaclast deposits of ireland a record of extreme waves in the north atlantic storms or tsunamis past occurrences of major tsunami in the global record have often been inferred from the presence of megaclast accumulations at significant heights above sea level which sometimes exhibit a pronounced seaward directed imbricate fabric the aran islands off the west coast of ireland exist in a marine environment which is totally unprotected from the most extreme sea states encountered in the north atlantic spectacular megaclast accumulations are found along the tops of vertical cliffs on these islands the elevation of these deposits varies from 0 m to 50 m above mean sea level and they include clasts weighing 250 tonnes at sea level over 117 tonnes at 12 m and 2 9 tonnes at 50 m above sea level imbrication measurements on these megaclasts indicate a well defined and consistent mean direction from the southwest for the emplacing waves one that is consistent with the prevalent storm wind direction for the area the megaclast accumulations are subject to episodic and on going erosion by cliff retreat but the existing accumulations are estimated to record events since at least 1839 recent emplacement and reworking is evidenced by trapped plastic detritus within the deposits and eyewitness accounts of large storms during which clasts have been emplaced similar deposits are found on the exposed coasts of the shetland and orkney islands off scotland there is at present no evidence of any tsunami in recorded history affecting the western irish and scottish coasts other than those generated by the lisbon earthquake of 1755 where the wave effects were slight thus the presence of megaclast accumulations at significant heights above sea level on exposed coasts and exhibiting imbrication should not be used as a definitive criterion for the past occurrence of tsunami these deposits attest to extreme wave conditions occasionally encountered in the north atlantic and act as a record of such events extending back at least 160 years such data on extreme wave conditions are essential for the prediction of the effects of deepwater waves on structures such as offshore drilling platforms

comments to dawson a g and stewart i 2007 tsunami deposits in the geological record sedimentary geology 200 166 183

extremely high energy wave deposits inside the great barrier reef australia determining the cause tsunami or tropical cyclone abstract a hydrodynamic approach is used to determine whether tsunami or cyclone generated waves were responsible for the deposition of fields of well imbricated rock boulders up to 290 tonnes along the coast of cairns inside the great barrier reef australia calculations of the overturning moments show that only tsunami are capable of moving such large boulders in this environment it is hypothesised that large tsunami 11 m have been able to penetrate the great barrier reef through wide 5 10 km 50 70 m deep passages between individual reefs three such passages each approximately 35 km apart and oriented in the same direction exist in the cairns region it is possible that these passages have funnelled and amplified palaeotsunamis the preferential location of eroded coral boulders up to 3 m in length on reef flats alongside these passages and their absence on other reefs throughout the region provide further evidence that extremely high energy waves have been able to penetrate the great barrier reef into the inner channel adjacent to the mainland carbon 14 ages of the coral boulders on these reef flats matches closely the ages of coral fragments pinned below the very large rock boulders along the coast these ages suggest that the cairns region has experienced large tsunami twice over the last millennium

boulder emplacement on a tectonically stable wave dominated coastline mission rocks northern kwazulu natal south africa abstract the presence of large boulders along rocky coastlines is a useful indicator as to the occurrence and nature of past storms and or tsunami field observations from mission rocks northern kwazulu natal south africa allowed for the assessment of historical high magnitude wave events in the area a total of 143 anomalously large boulders were assessed in terms of their dimensions morphologies and distribution along a regionally developed 3 m raised shore platform based on long intermediate and short axes relationships we calculate boulder masses of up to 9 03 t that were found to have been transported horizontally shoreward for up to 65 m based on geomorphological evidence we infer that the majority of boulders encountered were from a joint bound pre transport setting additionally overturning of the boulders was apparent we assess the boulder field numerically via the numerical model of pignatelli et al 2009 which we deemed most applicable for slab like boulders such as those encountered here results yielded a maximum breaking storm wave height of 11 36 m or a maximum tsunami height of 2 84 m an analysis of swell data revealed that the modelled storm wave heights fell within the range defined by the storm wave records for the area within the past 32 years boulder alignments were likewise compatible with the wave regime of the northern kwazulu natal coastline additional review of offshore seismic records and landslide hazards on the tectonically stable passive margin show that the tsunami hazard for landslides within the area is negligible the findings suggest a storm provenance as the causal mechanism for boulder emplacement at mission rocks

controls on timing of exhumation and deformation in the northern peruvian eastern andean wedge as inferred from low temperature thermochronology and balanced cross section in northern peru a 500 km long regional balanced section has been constructed across the eastern andean wedge using fieldwork industrial seismic sections and wells the structure is characterized by a thin skinned thrust system involving the eastern cordillera ec the sub andean zone saz and the maranon foredeep in the saz and the easternmost foredeep the development of the thrust system has been driven by the combination of two structural events permian thrust faults had been reactivated to form a basement duplex underlying the saz and the foredeep at the same time a triassic jurassic extensional basin has been transported as a crustal ramp anticline on to the duplex roof fault giving rise to the ec the impingement of the ec was responsible for the deformation of the saz and the propagation of the thrust wedge the minimum shortening calculated is 142 km representing a shortening strain of 28 a sequential restoration calibrated by u th he and fission track dating on apatites and vitrinite reflectance values shows that shortening rates vary from 7 1 mm yr 1 between 17 and 8 ma to 3 6 mm yr 1 between 8 ma and today and suggests that the thrust wedge commenced propagation between 30 and 24 ma when compared with other andean thrust wedges we suggest that the timing of the thrust wedge propagation is not a simple function of the distance to the hinge of the bolivian orocline and the propagation is not controlled by the precipitation regime we rather suggest that reactivated basement faults favored thrust wedge propagation

tsunami deposits on the coastline of west crete greece abstract the eastern mediterranean and the aegean sea in particular are the most active seismic regions in europe historically numerous earthquakes have occurred in this part of the world and comprehensive tsunami recordings exist nevertheless field evidence of tsunamis is rare although many neotectonic movements certainly must have triggered very strong tsunami waves along the coastlines of western crete we found evidence for tsunami impacts such as 1 bimodal deposits large clasts floating in sands comprised of shell fragments 2 dislocation of large boulders with tilting of biogenous notches and 3 boulders with lithophaga or cliona borings weighing up to 75 tons thrown onshore and imbedded in strata of marine shells this paper documents these deposits and discusses whether they originated from the sudden uplift that occurred in 365 ad moreover numerical radiocarbon ages reveal the occurrence of two tsunamis dated to 5660 yrs bp and 500 yrs bp evidence for other tsunami impacts is discussed but not supported by numerical dating due to the lack of suitable material

stable imbrication and delicate unstable settings in coastal boulder deposits indicators for tsunami dislocation abstract medium sized and coarse debris pebbles and boulders can exhibit patterns of setting particularly if they are elongated or tabular these patterns such as imbrication indicate certain transport processes mostly as to direction and character many years of observation and measuring of coarse coastal deposits are the basis for the conclusions presented here on environmental transport processes their character and their energy beside imbrication special emphasis is given to unstable or delicate settings of large boulders that evidently have remained in these positions from hundreds to thousands of years this deserves an explanation to how they arrived at these positions and why they have not changed into a more stable position given an environment of constant energy input along coastlines the discussion lays emphasis on whether both settings of mega boulders can be indicative of tsunami transport processes

clast mobility within boulder beaches over two winters in galicia northwestern spain abstract a micro drone was used to make low altitude flights over boulder beaches at laxe brava and oia in galicia northwestern spain flights were made in july 2012 may 2013 and spring 2014 high resolution digital terrain models and orthophotographs combined with gis mapping were used to monitor changes in the position of thousands of boulders maximum storm wave height was higher in the winter of 2013 2014 than in winter 2012 2013 and this was reflected in an increase in the proportion of the boulders that moved in the two winters from 17 to almost 48 at laxe brava and from 53 to almost 88 at oia the greater mobility of the boulders at oia can be attributed in part to their generally smaller size although there was considerable overlap between the size of boulders that moved and those that did not move within and between the two beaches there were mobile boulders in areas up to several metres above the high tidal level on both beaches and boulder transport in the shore normal and alongshore directions triggered some changes in the beach profiles particularly in the middle to upper parts of the beaches estimates of threshold transport conditions scaled to boulder mass breaker height and other variables suggested that all but the very largest boulders on the two beaches should have been mobile even during the summer months when the waves were much lower than in winter model over prediction can be attributed to a number of factors including constraints on movement imposed by surrounding boulders differences in boulder size and their effect on pivoting angles and on the degree to which boulders are exposed or sheltered from wave impact and difficulties in assigning appropriate values to model coefficients

an integrated analysis of an orogen sedimentary basin pair latest cretaceous cenozoic evolution of the linked eastern cordillera orogen and the llanos foreland basin of colombia the integration of restored basin geometry and internal features of syntectonic units e g stratal architecture thickness sandstone composition with fl exural modeling of the lithosphere constrains the evolution of a basin and its fl exural history related to orogenic growth spatial temporal loading confi guration using this approach we determined the maastrichtian cenozoic polyphase growth of the eastern cordillera of colombia an inverted mesozoic extensional basin the record of this growth occurs in an andean post middle miocene thrust belt the eastern cordillera and in adjacent foreland basins such as the llanos basin to the east this approach permitted the identifi cation of fitectono stratigraphic sequences in the foreland basin and fi ve phases of shortening for the eastern cordillera thermochronological and geochronological data support the spatial and temporal evolution of the orogen foreland basin pair tectono stratigraphic sequences were identifi ed in two restored cross sections one located at a salient and the other in a recess on the eastern fl ank of the eastern cordillera the lower two sequences correspond to late maastrichtian paleocene fl exural events and record the eastward migration of both tectonic loading and depositional zero in the llanos basin these sequences consist of amalgamated quartzarenites that abruptly grade upward to organic rich fi ne grained beds and to the top light colored mudstones interbedded with litharenites in isolated channels amalgamated conglomeratic quartzose sandstones of the third sequence record 15 m y of slow subsidence in the llanos basin and llanos foothills during early to middle eocene time while shortening was taking place farther west in the magdalena valley the fourth sequence of late eocene middle miocene age records a new episode of eastward migration of tectonic loads and depositional zero in the llanos basin this sequence begins with deposition of thick fi ne grained strata to the west whereas to the east in the llanos basin amalgamated quartzarenites unconformably overlie cretaceous and older rocks former forebulge apatite fi ssion tracks in the axial zone of the eastern cordillera growth strata in the

detrital zircon u pb geochronology constrains the age of brazilian neogene deposits from western amazonia abstract the fossiliferous beds of the solimoes formation western brazilian amazon have yielded several vertebrate fossils that are key to understand the evolution of neotropical biotas although this sedimentary unit has been studied for more than two centuries no absolute dates are available so far preventing more precise bio chronostratigraphic interpretations and broader comprehension of the biotic geological events that affected this northern portion of south america during the neogene here we present the first neogene radioisotopic dates for the brazilian amazon via u pb dating of detrital zircon from two classical sites both samples have small proportions of relatively young zircon grains the dates from which are the maximum ages of deposition la icpms analysis of two grains from the niteroi locality yielded a weighted mean of 8 5 0 5 ma and ca tims analysis of two grains from the talisma locality yielded a weighted mean of 10 89 0 13 ma these maximum deposition ages are in the tortonian stage late miocene confirming the age previously inferred based on biochronological data

distribution origin and transport process of boulders deposited by the 2004 indian ocean tsunami at pakarang cape thailand abstract the tsunami of 2004 in the indian ocean transported thousands of meters long boulders shoreward at pakarang cape thailand we investigated size position and long axis orientation of 467 boulders at the cape most of boulders found at the cape are well rounded ellipsoid in shape without sharp broken edges they were fragments of reef rocks and their sizes were estimated to be 3 22 7t the distribution pattern and orientation of long axis of boulders reflect the inundation pattern and behavior of the tsunami waves it was found that there is no clear evidence indicating monotonous fine coarse shoreward trends of these boulders along each transect line on the other hand the large boulders were deposited repeatedly along the three arcuate lines at the intertidal zone with a spacing of approximately 136m interval this distribution pattern may suggest that long lasting oscillatory flows might have repositioned the boulders and separated the big ones from small no boulders were found on land indicating that the hydraulic force of the tsunami wave rapidly dissipated on reaching the land due to the higher bottom friction and the presence of a steep slope we further conducted numerical calculation of tsunami inundation at pakarang cape according to the calculation the sea receded and the major part of the tidal bench area with boulders at present was exposed above the sea surface before the arrival of the first tsunami wave the first tsunami wave arrived at the cape from west to east at approximately 130min after the tsunami generation and then inundated inlands our calculation shows that tsunami wave was focused around the offshore by a small cove at the reef edge and spread afterwards in a fan like shape on the tidal bench the critical wave velocities necessary to move the largest and average size boulders by sliding can be estimated to be approximately 3 2 and 2 0m s respectively the numerical result indicates that the maximum current velocity of the first tsunami wave was estimated to be from 8 to 15m s between the reef edge and approximately 500m further offshore this range is large enough for moving even the largest boulder shoreward these suggest that the tsunami waves that were directed eastward struck the reef rocks and coral colonies originally located on the shallow sea bottom near the reef edge and detached and transported the boulders shoreward

testing the numerical models for boulder transport through high energy marine wave event an example from southern saurashtra western india abstract presence of large boulders along rocky coasts can be used as archives to reconstruct past extreme wave event history vital for the coastal hazard assessment dimensions of boulders lying in supratidal zone have been used to reconstruct the origin of wave responsible for their transport and processes there are several mathematical equations available which take into account submerged subaerial and joint bounded block scenarios for boulder transport to estimate the wave height required to transport the boulders to their final position however there are limited studies which validate these equations using modeling and observational analysis navabandar coast situated in western india provides an excellent opportunity for such analysis as there exists three boulders derived from shore platform during the november 1982 storm we present the analysis of these boulders and event history of region to conclude that all the mathematical equations overestimate the wave heights required to dislodge and transport these boulders by at least 5 times the actual event we emphasize that there is a vital need to re evaluate and improve the existing equations considering the local control variables for better visualization of palaeo tsunami storm events

an initial evaluation of drone based monitoring of boulder beaches in galicia north western spain low altitude flights by a micro drone were made in 2012 and 2013 over two boulder beaches in north western spain geographical information system software was used to map the data boulder outlines from the first flight were recorded on 4796 clasts at laxe brava and 2508 clasts at oia changes in location were identified by overlaying these outlines on the 2013 images about 17 5 of the boulders mean surface area 0 32 m2 moved at laxe brava and about 53 mean surface area 0 23 m2 at oia most movement on both beaches was between the mid tide to about 2 m above the high tidal level the location and elevation of the highest points were also recorded on the 2012 images on 4093 boulders at laxe brava and 3324 boulders at oia these elevations were compared with the elevations at the same locations in 2013 the occurrence and scale of the elevational changes were generally consistent with changes in the boulder outlines the study confirmed that boulder beaches can be cheaply and effectively monitored using high resolution micro drone technology copyright 2014 john wiley sons ltd

a molecular evaluation of bulk organic carbon isotope chemostratigraphy for terrestrial correlations an example from two paleocene eocene tropical sequences abstract the dynamics associated with the carbon cycle and the linkage between the oceans the atmosphere and land plants provide an opportunity to correlate marine and terrestrial sedimentary sequences using stable isotopes of carbon 13 c but few studies have tested this approach for instance it has been proposed that changes in plant community e g gymnosperm dominated vs angiosperm dominated could have significantly altered amplified the carbon isotope ratios of bulk sedimentary organic matter derived from land plants 13 c tom compared to that of the marine carbonates 13 c carbonate here 13 c tom values in a terrestrial sequence of the colombian tropics are compared to the composite paleocene eocene 13 c carbonate curve from zachos et al 2001 to evaluate the use of 13 c tom values as a reliable chronostratigraphic tool sediments of the studied terrestrial sequences were deposited in a transitional setting dominated by mudstones coals and small lenses of sandstones late cretaceous middle paleocene sediments and in a mixture of deltaic and fluvial conditions late paleocene early eocene sediments the biostratigraphic control was based on palynological zones for the region the 13 c tom values for the studied terrestrial sequence show three carbon isotope excursions which correlate closely with those present in the marine record the 13 c tom values decreased from 24 2 to 26 5 in sediments accumulated during early to middle paleocene increased from 26 5 to 23 8 during the late paleocene and decreased from 23 8 to 26 5 near the paleocene eocene boundary 52 50 ma selected biomarkers indicate that most of the organic matter derived from both gymnosperms and angiosperms moreover the analyses of selected biomarker ratios cpi pr ph p aq and hopanes show some diagenetic transformation in the preserved organic matter however no correlation between diagenesis and 13 c tom values was detected thus suggesting that 13 c tom could be correlated with 13 c carbonate values the close correspondence that was found between 13 c tom and 13 c carbonate values 13 c tom carbonate 27 provides support to the hypothesis that a tight land plant oceans linkage exists through geologic timescales via atmospheric carbon dioxide

miocene paleoenvironmental changes in the solimoes basin western amazon brazil a reconstruction based on palynofacies analysis abstract we report palynofacies from two sections of miocene solimoes formation of the solimoes basin western amazon brazil to better understand paleoenvironmental evolution based on cluster analysis five palynofacies associations were recognized dominated by either opaque non opaque algae miospores and structureless marine organic matter the distribution of palynofacies associations reflects a complex depositional system with fluvial lacustrine estuarine and shallow marine environments a high abundance of woody material indicates a fluvial lacustrine dominated environment three marine incursions were recognized indicated by the presence of dinoflagellate cysts and microforaminifera test linings marine influence was more evident during the late middle late miocene interval when transgressions occurred over a greater extent of the amazon region

historical and pre historical tsunamis in the mediterranean and its connected seas geological signatures generation mechanisms and coastal impacts abstract the origin of tsunamis in the mediterranean region and its connected seas including the marmara sea the black sea and the sw iberian margin in the ne atlantic ocean is reviewed within the geological and seismotectonic settings of the region a variety of historical documentary sources combined with evidence from onshore and offshore geological signatures geomorphological imprints observations from selected coastal archeological sites as well as instrumental records eyewitnesses accounts and pictorial material clearly indicate that tsunami sources both seismic and non seismic e g volcanism landslides can be found in all the seas of the region with a variable tsunamigenic potential local regional and basin wide tsunamis have been documented an improved map of 22 main tsunamigenic zones and their relative potential for tsunami generation is presented from west to east the most important tsunamigenic zones are situated offshore sw iberia in the north algerian margin in the tyrrhenian calabria and messina straits in the western and eastern segments of the hellenic arc in the corinth gulf of central greece in the levantine sea offshore the dead sea transform fault and in the eastern side of the marmara sea important historical examples including destructive tsunamis associated with large earthquakes are presented the mean recurrence of strong tsunamis in the several basins varies greatly but the highest event frequency 1 96 years is observed in the east mediterranean basin for most of the historical events it is still unclear which was the causative seismic source and if the tsunami was caused by co seismic slip by earthquake triggered submarine landslides or by a combination of both mechanisms in pre historical times submarine volcanic eruptions i e caldera collapse massive pyroclastic flows volcanogenic landslides and large submarine landslides caused important tsunamis although little is known about their source mechanisms we conclude that further investigation of the tsunami generation mechanisms is of primary importance in the mediterranean region inputs from tsunami numerical modeling as well as from empirical discrimination criteria for characterizing tsunami sources have been proved particularly effective for recent well documented aseismic landslide tsunamis e g 1963 corinth gulf 1979 cote d azur 1999 izmit bay 2002 stromboli volcano since the tsunami generation mechanisms are controlled by a variety of factors and given that the knowledge of past tsunami activity is the cornerstone for undertaking tsunami risk mitigation action future interdisciplinary research efforts on past tsunamis are needed

geomorphological control on boulder transport and coastal erosion before during and after an extreme extra tropical cyclone extreme wave events in coastal zones are principal drivers of geomorphic change evidence of boulder entrainment and erosional impact during storms is increasing however there is currently poor time coupling between pre and post storm measurements of coastal boulder deposits importantly there are no data reporting shore platform erosion boulder entrainment and or boulder transport during storm events rock coast dynamics during storm events are currently unexplored here we use high resolution daily field data to measure and characterize coastal boulder transport before during and after the extreme northeast atlantic extra tropical cyclone johanna in march 2008 forty eight limestone fine medium boulders n 46 and coarse cobbles n 2 were tracked daily over a 0 1 km2 intertidal area during this multi day storm boulders were repeatedly entrained transported and deposited and in some cases broken down n 1 or quarried n 3 during the most intense days of the storm eighty one percent n 39 of boulders were located at both the start and end of the storm of these 92 were entrained where entrainment patterns were closely aligned to wave parameters these data firmly demonstrate rock coasts are dynamic and vulnerable under storm conditions no statistically significant relationship was found between boulder size mass and net transport distance graphical analyses suggest that boulder size limits the maximum longshore transport distance but that for the majority of boulders lying under this threshold other factors influence transport distance paired analysis of 20 similar sized and shaped boulders in different morphogenic zones demonstrates that geomorphological control affects entrainment and transport distance where net transport distances were up to 39 times less where geomorphological control was greatest these results have important implications for understanding and for accurately measuring and modelling boulder entrainment and transport coastal managers require these data for assessing erosion risk 2016 the authors earth surface processes and landforms published by john wiley sons ltd

variation in collagen stable nitrogen values in black tailed jackrabbits lepus californicus in relation to small scale differences in climate soil and topography abstract longstanding observations about the relationship between increasing aridity and 15 n enrichment in mammalian collagen values have led to an interest in their use as a paleoclimatic marker here we report on variability in collagen nitrogen values from five modern and two archaeological samples of black tailed jackrabbits lepus californicus from the eastern great basin of the united states n 178 individuals nitrogen 15 n values were highly variable within all samples modern samples showed significant differences despite similarities in average annual precipitation and temperature archaeological samples were indistinguishable from each other or from modern samples taken from the same area despite independent evidence for differences in precipitation for the two prehistoric periods considered differences between modern samples were most strongly associated with soil characteristics we discuss these results in light of their relationship with topography and vegetation and highlight their implications for archaeological applications of stable nitrogen analyses in several contexts

how does the nazca ridge subduction influence the modern amazonian foreland basin the subduction of an aseismic ridge has important consequences on the dynamics of the overriding upper plate in the central andes the nazca ridge subduction imprint can be tracked on the eastern side of the andes the fitzcarrald arch is the long wavelength topography response of the nazca ridge flat subduction 750 km inboard of the trench this uplift is responsible for the atypical three dimensional shape of the amazonian forelland basin the fitzearrald arch uplift is no older than pliocene as constrained by the study of neogene sediments and geomorphic markers according to the kinematics of the nazca ridge subduction

impact of holocene tsunamis detected in lagoonal environments on corfu ionian islands greece geomorphological sedimentary and microfaunal evidence abstract in this paper we present for the first time geomorphological sedimentary and microfaunal evidence of palaeotsunami impact on corfu ionian islands greece the island of corfu is located in an area of exceptional tectonic stress towards the south the african oceanic plate is being subducted underneath the aegean plate whereas towards the north the adriatic and european plates form a continental collision zone recent publications provide evidence of earthquake related co seismic movements that potentially trigger extreme wave events as well as relative sea level fluctuations in this context we investigated two selected near coast geological archives the chalikiopoulou lagoon in the east and the korission lagoon in the southwest of corfu island our results clearly document that the eastern as well as the southwestern coasts of corfu were repeatedly affected by palaeotsunami impact during the holocene with regard to the local topographical constellation and the recent geomorphodynamic potential of each study area evidence of high energy wave impact is based on the stratigraphical and microfaunal record of selected vibracoring sites as well as on numerical modelling results it is concluded that the eastern coast of corfu is preferably affected by high energy wave impacts from a southern direction such impacts are most likely related to teletsunamis from the major seismical zone of the hellenic trench in contrast the southwestern coast of corfu is endangered by impacts from both western and southern directions such impacts may comprise teletsunamis triggered in the hellenic trench or the etna regions but may also be caused by local submarine landslides at the steeply sloping continental shelf directly west of corfu our study builds a bridge between palaeotsunami research conducted in the southern ionian sea and the adriatic sea and allows to better discriminate between the effects of teletsunamis and locally triggered events within one of the seismically most active regions in the eastern mediterranean

from fine sand to boulders examining the relationship between beach face slope and sediment size abstract it is a long standing maxim that coarser sediment sizes are associated with steeper beach face slopes but because most work has focused on sandy beaches few data are available for the pebble cobble or boulder size ranges little is known therefore about how beach morphology and grain size relate at the coarser size grades we compiled data from the literature 2144 measurements of beach face slope with associated grain sizes covering the range from very fine sand to boulders this meta analysis shows that beach faces do tend to steepen as average grain size increases at least up to the cobble size range but the trend is not simple although previous studies suggested a simple power law relationship between grain size and beach face slope in fact the data distribution is best fit by a curve that is steep at the finer grain sizes but is much more gentle as grain size coarsens and may trend downward for boulders fine and medium sands have the greatest range of reported slopes and the data support the importance of effective weight modification and boundary layer dynamics as primary controls on beach face steepness at these fine size grades around the very coarse sand size grade a plateau marks a shift in beach dynamics as hydraulic conductivity increases beaches switch to being infiltration dominated the trend toward steeper slopes continues but at a lower and steady rate from granules through cobbles there appears to be a falloff in slope for the coarsest boulder deposits but we note that this is based on very few locations so should be considered preliminary the overall data distribution is described by a power law function tan a d 50 0 125 b c the broadness of each transition zone also shows that a range of factors other than grain size governs where that tipping point occurs in the cobble and boulder size ranges there are two deposit categories boulder beaches and supratidal boulder ridges although not commonly thought of as beaches boulder ridges record long term storm deposition and reworking on the highest energy coasts supratidal ridges and boulder beaches seem to show different slope grain size relationships with the steepest slopes occurring in boulder ridges and with boulder beaches showing more gentle gradients than other coarse clastic beaches but our data set reveals how little quantitative information exists about the coarsest end of the beach spectrum and invites further work to investigate the sedimentology of cobble and boulder dominated systems

a scenario for late neogene andean shortening transfer in the camisea subandean zone peru 12 s implications for growth of the northern andean plateau precise knowledge of the timing of deformation in the subandean zone of the andean plateau is a prerequisite for deciphering the late neogene growth of the andean plateau in this paper we report new apatite fission track aft and vitrinite reflectance ro data for a regional balanced cross section of the camisea basin in the central peruvian subandean zone adjacent to the northern andean plateau the balanced cross section shows that the structure of this basin is characterized by a broad internal passive roof duplex and external thrust related anticlines the balanced cross section restoration shows 53 km 39 of total horizontal shortening we sampled paleozoic to cenozoic sedimentary strata for aft and ro analyses along the 4 km thick vertical profile of the mainique back thrust passive roof thrust the innermost preserved subandean structure young components of aft ages are spread between ca 6 ma and ca 24 ma a break in the slope in the aft ages determines the geometry of the miocene partial annealing zone and the exhumation of the mainique back thrust at ca 6 ma sequential restoration calibrated by aft and ro data indicates that the last 23 km horizontal shortening were accommodated by the camisea thrust system over the past 6 m y giving a mean shortening rate of 3 8 mm yr using this shortening rate for the first 30 km horizontal shortening we calculate that the andean shortening transfer into the peruvian subandean zone initially started at ca 14 ma this result suggests that the transfer of shortening from the northern andean plateau to the subandean zone occurred prior to the removal of dense lithosphere previously reported to have occurred between ca 10 ma and ca 7 ma we rather propose that the late neogene growth of the northern andean plateau mostly resulted from a continuous crustal shortening combined with lower crustal flow

the largest local tsunami in 20th century hawaii abstract the 1975 kalapana tsunami had waves that ran up to 14 6 m high it deposited a discontinuous basalt boulder and carbonate sand veneer on the halape apua point coast of the island of hawaii these deposits fine up to 320 m inland and 10 4 masl the deposit is an unusual sedimentary association in which sand sized material is a minor component both boulders and sand fine inland over the same distance not in a continuum and they terminate at approximately the same point boulders were transported and deposited by only one wave the second whereas the sand deposit was in part reworked by subsequent smaller waves boulder transport by one wave in association with a relative paucity of finer sediment reduced internal clast interference and helped to impart a marked fining inland sequence this fining inland sequence is at odds with work that proposes a chaotic or random nature of boulder emplacement by tsunamis where there is abundant sediment clast interference during entrainment will impede the fining inland of larger material in cases where it is difficult to determine the nature of inundation or the number of tsunamis a chaotic pattern may simply reflect deposition by storm tsunami or a combination of the two

geomorphological effects of tsunami run up and backwash abstract geomorphological processes associated with tsunami run up and backwash are highly complex to date most studies have considered the sedimentology of palaeo tsunamis while almost no detailed studies have been undertaken in areas known to have been affected by tsunamis in recent times research on contemporary tsunamis show that coastal landscapes may be greatly altered not only by direct tsunami run up orthogonal to the shoreline but also by episodes of vigorous backwash and by water flow sub parallel to the coastline the combined effect of these processes produces hitherto unrecognised coastal landforms that are dominated by the effects of high magnitude erosion and deposition deposition of large boulders is also associated with severe tsunamis while in adjacent areas run up processes often result in the deposition of continuous and discontinuous sediment sheets in many instances the upper limit of sediment deposition lies well below the upper limit of wave run up which is frequently marked by a well defined zone of stripped vegetation and soil the processes described have considerable implications for models of coastal evolution it may even be the case that the evolution of particular stretches of coastline are dominated by such high magnitude low frequency events

boulder accumulations produced by the 20th of february 1743 tsunami along the coast of southeastern salento apulia region italy abstract the detachment of large boulders in the nearshore zone and their deposition farther inland are the main morphological effects of tsunamis on rocky coasts along the otranto leuca coast southeastern apulia italy two boulder accumulations have been recognized and studied at the torre sasso locality boulders weighing up to 31 t are scattered from sea level to about 5 m of elevation and clustered in groups of several imbricated elements at torre s emiliano an impressive accumulation made of large boulders has been recognized and studied the accumulation is about 30 m wide and follows the present coastline for about 2 5 km at a variable distance of 15 to 40 m looking closer it is compounded by two ridges the ridge closer to the coastline shows a very steep slope seaward made of very large boulders emplaced in a vertical position its top reaches about 11 m above m s l the inner belt is lower than the outer one and consists of smaller boulders it partly covers a 2 m thick colluvial deposit made of reddish sands huge blocks weighing up to 70 t cover the carved surface stretching from the coastline to the front of the first ridge analysis of the imbrication axes indicates that the catastrophic waves responsible for the development of the boulder accumulations most likely propagated from sse to nnw direction karstic features occurring on the surface of the innermost boulders indicate a very recent age for their deposition as no differences have been found between the aerial exposed surface and the soil covered one three ams radiocarbon age determinations performed on marine shells found landward the boulders have accumulated recently i e within the last three centuries moreover archeological remains in the top layers of the colluvial deposits covered by the boulders can be referenced to 16th 17th centuries this evidence suggests that the 20th of february 1743 earthquake was responsible for the generation of two large tsunami waves which caused the boulder accumulations to deposit this earthquake was particularly violent in the salento region where it reached grade ix on the mcs scale interestingly chronicles of this event record a withdrawal of the sea in the brindisi harbour north of the study area this study highlights the tsunamigenic potential offshore the southeastern salento coast requiring that further strategies be devoted to mitigate the tsunami risk

emplacement and movement of boulders by known storm waves field evidence from the okinawa islands japan abstract field observations from previous studies of boulder movements were compiled to augment our own work on boulders that have been displaced by storm waves during recent typhoon events in the okinawa islands japan to elucidate the ability of storm waves to move boulders our observations reveal that recent storm waves displaced by sliding and overturning 100 ton boulders emplacing them on the reef or high cliff tops and that storm waves might also be capable of displacing 200 ton boulders on the reef the weights of storm wave boulders at the okinawa islands are of comparable order to those boulders displaced by historical tsunami origins consequently boulder weight alone is an inappropriate parameter to discriminate between tsunami or storm wave processes however these heavy storm wave boulders are close to the reef and cliff edges while tsunami boulders can be deposited much further inland hence horizontal displacement distance of boulders could be a useful parameter to discriminate boulders deposited by the tsunami and storm waves on the wide fringing reef the storm wave boulders were characteristically concentrated on the southeastern pacific ocean sides of each island but large boulders are rarely found on the northwestern east china sea side this is probably because the storm wave intensities are generally stronger at the southeastern side than at the northwestern side although differences of reef strength and initial condition of boulders should also be taken into account consideration of the high frequency of typhoons at the area suggests that effects of the storm waves and the consequent displacement of boulders on the reef might have contributed to the formation of the reef moat framework that typifies the okinawa islands especially if the moat is located within the transport limit of the storm wave boulders approximately 300 m from the reef edge at the islands

soft sediment deformation structures interpreted as seismites in middle late pleistocene aeolian deposits apulian foreland southern italy abstract soft sediment deformation structures in middle late pleistocene deposits of torre san gennaro brindisi southern italy have been analysed from a morphologic point of view the deformational structures are represented by deformed cross bedding and large injection structures they are restricted to aeolian sediments and the mechanism of deformation is related to liquefaction and or fluidization processes the liquefaction and or fluidization processes have been interpreted as seismic induced after consideration of all other possible trigger agents the discussion about the possible source areas of the palaeoseismic event was carried out through the analysis both of the general magnitude distance relations and the main structural features of the study zone in conclusion we consider the key criteria for trigger mechanism interpretation of soft sediment deformation structures in aeolian deposits and the actual feasibility of using aeolian sediments for the palaeoseismic studies

boulder coastal deposits at favignana island rocky coast sicily italy litho structural and hydrodynamic control abstract boulders are frequently dislodged from rock platforms transported and deposited along coastal zones by high magnitude storm waves or tsunamis their size and shape are often controlled by the thickness of bedding planes as well as by high angle to bedding fracture network we investigate these processes along two coastal areas of favignana island by integrating geological data for 81 boulders 49 rupture surfaces called sockets and fracture orientation and spacing with four radiocarbon dates numerical hydrodynamic analysis and hindcast numerical simulation data boulders are scattered along the carbonate platform as isolated blocks or in small groups which form as a whole a discontinuous berm underwater surveys also highlight free boulders with sharp edges and sockets carved out in the rock platform boulders are composed of ruditic to arenitic size clastic carbonates their size ranges from 0 6 to 3 7 m 0 55 to 2 4 m and 0 2 to 1 m on the major a medium b and minor c axes respectively the highest value of mass estimation is 12 5 t almost all of boulders and sockets are characterized by a tabular or bladed shape the comparisons between a the fractures spacing and the length of a and b axes and b the frequency peaks of c axis with the recurrent thickness of beds measured along the coastal zone demonstrate the litho structural control in the size and shape of joint bounded boulders these comparisons together with the similarity between the shapes of the boulders and those of the sockets as well as between the lithology of boulders and the areas surrounding the sockets suggest that blocks originate by detachment from the platform edge thus the most common pre transport setting is the joint bounded scenario hydrodynamic equations estimate that the storm wave heights necessary to initiate the transport of blocks diverge from 2 m to 8 m for joint bounded boulders and from few tens of centimeters up to 11 m for submerged boulders the comparison between the wave heights at the breaking point of the coastal zones with the results of hydrodynamic equations shows that waves approaching the coastline are able to transport all surveyed boulders our data suggest that boulders have been transported by several storm events even in very recent times

ghost of seagrasses past using sirenians as a proxy for historical distribution of seagrasses abstract seagrasses are a notable component of shallow marine habitats especially in tropical and subtropical regions their fossil record extends back to the mesozoic but it is relatively poor and fragmentary with large temporal and geographical gaps as a result very little is known about the paleobiogeography of these plants and how physical drivers such as climatic or oceanic events have affected their distribution one approach is to infer the past distribution of seagrasses using fossils of organisms dependent of seagrasses with more complete records as proxies seagrass consumers such as sirenians seacows manatees and dugongs are much better represented in the fossil record than seagrasses are the characteristically dense bones of sirenians together with the fact that they are usually found in marginal marine environments increases the potential for preservation and recognition of their fossils the long evolutionary history of sirenians extending throughout most of the last 50 ma together with their diet permits the use of their fossils as a proxy for inferring the paleobiogeography of seagrasses here i looked at the fossil record of sirenians and seagrasses from the eocene through the miocene epochs this comparison produced several inferences about seagrass paleobiogeography and how physical drivers such as climate change ocean currents and tectonic events have been influential in their distribution 1 seagrasses were well established in the western atlantic caribbean prior to the middle eocene making possible at least two instances of trans atlantic sirenian dispersal events either with the aid of tethyan currents or along the nearly continuous northern atlantic coastline that was present in the eocene 2 climatic cooling during the early oligocene seemed to have limited the extent of seagrasses and sirenians although these groups recovered and further diversified and expanded their distributions by the late oligocene in tandem with a climatic warming event 3 by the miocene seagrasses and sirenians reached the southern western atlantic and the eastern pacific aided by the presence of the central american seaway achieving a distribution similar to and sometimes surpassing that of today the fossil record of sirenians can provide a broad overview of seagrass paleobiogeography through time however several aspects such as when sirenians and seagrasses arrived to australia and the seemingly late arrival of seagrasses to south america and the eastern pacific still need further investigation

sedimentation et fracturation de haute energie en milieu recifal tsunamis ouragans et cyclones et leurs effets sur la sedimentologie et la geomorphologie d un atoll motu et hoa a rangiroa tuamotu pacifique se abstract a longitudinal festoon fracture of the reef flat widened by slow biological and mechanical erosion transverse along the grooves divides the nw coral rim of rangiroa tuamotu se pacific into colossal blocks 15 10 5 m 1500 t the elaboration of these blocks can be attributed to the dislocation of the top of the reef flat by catastrophic events tsunamis or hurricanes typhoons in the sw and s pacific the shifting of these blocks mega boulders would necessitate a considerable amount of energy and at present we cannot decide which one of these phenomena was responsible various examples observed in the pacific are cited to illustrate abrupt changes in the sea level these could be attributed either to meteorological events hurricanes cyclones or typhoons or to seismic events of very high energy ground sea or tsunamis the reader is reminded of the different characteristics that these phenomena produce this study is mainly concerned with tsunamis especially the frequency of their occurrence energy and effects on the coasts of small oceanic islands hurricanes cyclones and typhoons roughly originate from the n ne and e whereas tsunamis originate from all directions except from se s and sw angle these very high energy events hurricanes and tsunamis seem then to be responsible for 1 the decreasing grain size of the coral rim sediments from the ocean to the lagoon through the range of colossal blocks smaller boulders scree gravels coarse and fine sands 2 the sedimentary accretion of the motu itself at each very high energy so called catastrophic event they are also responsible for the preservation of the two characteristic geomorphic forms of an atoll motu and hoa 3 finally the alternation motu hoa motu etc on the coral rim this alternation seems to result from the interaction between oceanic disturbances hurricanes or tsunamis and the water volume which must flow over the coral rim the transported material the reef flat and the angle of incidence between the swell and the coast during these catastrophic events

distribution geomorphology and lithofacies of cliff top storm deposits examples from the high energy coasts of scotland and ireland abstract cliff top storm deposits ctsds occur on cliffs at elevations of up to 50 m above sea level at exposed sites on the deep water coasts of the british isles this study examines the distribution geomorphology and lithofacies of ctsds at sites from shetland orkney caithness and the outer hebrides in scotland and from the aran islands in galway bay in ireland ctsds are generated largely by the quarrying of blocks from the cliff top and transported by green water bores across cliff top platforms and ramps to be deposited in backing ridges or as debris spreads maximum boulder sizes reach 48 m 3 but it is likely that much larger blocks can be quarried prior to disintegration during transport eye witness accounts and field mapping demonstrate that formation and modification of ctsds has continued during major storms over recent decades recent ctsds bury a range of man made debris but older deposits lack this and instead show weathering effects that indicate a longer residence time in shetland osl dates on intercalated sands suggest that the oldest ctsds date from 800 ad radiocarbon dates on shell buried inside ctsd ridges relate to major storms between 1700 and 1900 ctsds represent an overlooked archive of storm sedimentation that has great potential for the elucidation of local storm chronologies ctsds also provide evidence of wave impacts on any part of the cliff face or top in fundamental contrast to the concentration of wave action at the cliff foot implicit in traditional models of the erosion of rock coasts

paleosol and ichnofossil evidence for significant neotropical habitat variation during the late middle miocene serravallian we use paleopedology and ichnology to elucidate the habitat of the late middle miocene fossil site of quebrada honda southern bolivia the paleosols represent three pedotypes type 1 and type 2 paleosols are interpreted as inceptisols eutrudepts and entisols udifluvents respectively which formed on proximal and distal floodplains in a seasonal sub humid to humid wooded grassland like vegetative community type 3 paleosols are interpreted as inceptisols calciustepts that formed in more densely vegetated wooded grassland like vegetative communities on distal floodplains in a strongly seasonal sub humid to semi arid environment the ichnofossil assemblage of quebrada honda includes celliforma coprinisphaera taenidium fictovichnus planolites skolithos katarrhedrites and root traces and represents heterogeneous communities dominated by soil arthropods and plants the physical and geochemical properties of the paleosols including low maturity poor development of horizons and the overall moderate estimates of mean annual precipitation indicate changes in soil moisture due to seasonal precipitation and flooding and low but varying degrees of temporal stability the diverse ichnofossil assemblage of quebrada honda reflects environments with greater primary productivity and temporal stability than those of nearby cerdas bolivia which are several million years older quebrada honda s inferred paleoenvironments differ markedly from those of la venta colombia indicating that dissimilar habitats may partly or principally account for the vastly different faunas of these two well sampled and contemporaneous fossil localities

sedimentological and geoarchaeological evidence of multiple tsunamigenic imprint on the bay of palairos pogonia akarnania nw greece abstract this paper presents evidence of multiple tsunami impact on the bay of palairos pogonia nw greece during the holocene based on detailed geo scientific studies altogether 41 vibracores were drilled to detect high energy influence in the stratigraphical record layers of coarse grained allochthonous marine deposits were found intersecting autochthonous fine grained back beach sediments in the palairos coastal plain on top of beach or marly bedrock units at pogonia beach and along the pogonia cliff section high energy deposits are associated with specific sedimentary structures such as fining upward sequences rip up clasts basal erosional contact bi to multimodal grain size distribution lamination and co existence of both well rounded and angular sharply edged components all of them typical of tsunami impact macro and microfaunal analyses revealed tsunami related input of numerous ex situ marine species and mostly angular shell debris into quiescent fresh to brackish water environments by high energy and long distance transport geophysical methods helped to find subsurface structures and to seize the lateral extent of tsunami layers ca fe ratios derived from xrf measurements were used to trace tsunami influence inland most important is the widespread spatial distribution of the tsunamites with a lateral extent between 70 m at the pogonia cliff section 200 m at pogonia beach and 1 km in the central palairos plain and overall tendencies of fining and thinning towards inland highest elevations of tsunamites were found around pogonia village at ca 7 5 m a s l vibracore data give evidence that the overall coastal evolution has been strongly affected locally even controlled by multiple high energy impact a conspicuous geoarchaeological tsunamite up to 1 5 m thick was found at pogonia cliff consisting of mixed marine sand pebbles bio erosively altered stones shell debris foraminifers and terrigenous material abundant ceramic fragments bones building material it is directly associated with the submerged remains of an ancient mole which was destroyed and its building material partly dislocated by the same event dating of tsunamites was accomplished by archaeological age determination of diagnostic sherds and by radiocarbon and luminescence dating techniques strong tsunami events were dated to the beginning of the 6th the mid 5th the 4th 3rd and the late 2nd millennia bc as well as to the 4th 3rd century bc on a regional scale the recurrence interval for large events is ca 500 1000 years at least twice during the late holocene the palairos coastal plain was flooded quasi contemporaneously from both the northern and southern side

geological and historical records of tsunami in australia abstract the indian ocean tsunami iot of 2004 has resulted in significant interest within australia about the record of tsunami for the continent because an understanding of tsunami hazard begins with a catalogue of past events here a preliminary catalogue of tsunami affecting australia is presented the catalogue contains entries for 57 tsunami events the oldest event is dated at 3 47 ga the most recent is the july 17th 2006 forty four tsunami were recorded on the new south wales coast although the nw coast of western australia records a significant number of events forty seven events have affected australia since ad1858 maximum run up for an historic event is 6 m asl whilst the maximum run up for a palaeotsunami event is reported at an elevation of at least 100 m asl twenty three percent of historic australian tsunami were generated by unknown causes and papua new guinea the solomon islands and indonesia collectively represent the most important source area of historic tsunami for australia geological records for palaeo and historic tsunami are identified and summarised the geological record of tsunami represents a potentially important source of information for australian tsunami however at the present time the geological record is both limited and controversial and future research should seek to re examine proposed geological evidence of tsunami from an analysis of this preliminary catalogue of australian tsunami a series of key research priorities have been identified to guide future research in the region

the origin and dynamics of coastal boulders in a semi enclosed shallow basin a northern adriatic case study abstract this paper documents the analysis of a coastal boulder deposit that was recently identified along the northern adriatic coast premantura promontory istria croatia accumulations of large boulders have not previously been reported in the northern adriatic which can be viewed as a semi enclosed basin a multidisciplinary approach was used to investigate the site including geological and geomorphological surveys together with the use of an unmanned aerial vehicle uav digital photogrammetric analysis hydrodynamic modelling and 14c ams datings measurements of boulder position elevation size shape and density were fed into hydrodynamic equations that are used to estimate the minimum storm and tsunami wave height required to enable the accumulation of boulders biogenic marine carbonate encrustations observed on 14 boulders suggest the infra and sublittoral zones as source areas while for most of the boulders a subaerial origin is hypothesised the boulder deposit occurs on a flat promontory where the topography together with the stratified limestone bedding planes and dense joint pattern constitute the predisposing factors for boulder size and detachment comparisons between satellite images taken between 2008 and 2017 pictures collected from internet and a 2012 snorkel survey of the istrian coast made it possible to highlight the emplacement of a boulder with an estimated weight of 7 65 t during late 2013 or early 2014 the study examines the mechanisms that may be responsible for the detachment and transport of these large limestone rock fragments from the emergent part of the coast and from the sea bed towards inland areas the results suggest the occurrence of very recent extreme weather conditions as well as multiple historical storm events and exclude a tsunami origin of the boulders

charophyte palaeoecology in the upper eocene of the eastern ebro basin catalonia spain biostratigraphic implications abstract a micropalaeontological study of the non marine upper eocene of the north eastern ebro basin catalonia spain was carried out to clarify the palaeoecology of well known charophyte species that are widely recognised as significant in charophyte biostratigraphy autochthonous specimens of the biozone index species harrisichara vasiformis tuberculata were found in marlstones from the sant boi formation middle part of the priabonian which are associated with brackish water ponds laterally related to paralic marshes in contrast laterally equivalent assemblages found in white laminated marls from stable freshwater lakes were devoid of the index species and were dominated by harrisichara lineata three more charophyte assemblages are reported from the continental artes formation stephanochara vectensis biozone upper priabonian assemblages dominated by the species nodosochara jorbae reported only from iberia at that age occur in marlstones related to freshwater temporary and turbid lakes within flood plains in medial fluvial fan environments however lychnothamnus grambastii dominates locally in similar environments with higher organic matter content laterally equivalent assemblages from freshwater perennial lakes in distal alluvial fan facies were dominated by the biozone index species harrisichara tuberculata these results provide evidence that important charophyte index species of the european charophyte biozonation were controlled by palaeoenvironmental factors such as water salinity lake level changes or terrigenous input to the lakes in consequence these species should be used with caution in biostratigraphic studies taking into account that their presence or absence may be palaeoecologically driven

coastal vulnerability to typhoon inundation in the bay of bangkok thailand evidence from carbonate boulder deposits on ko larn island abstract at the head of the gulf of thailand the subsiding chao phraya delta and adjacent low lying coastlines surrounding the bay of bangkok are at risk of coastal flooding although a significant marine inundation event has not been experienced in historical times this work identifies coastal depositional evidence for high energy waves in the past on ko larn island in eastern bay of bangkok numerous coastal carbonate boulders ccbs were discovered at elevations up to 4 m above sea level the largest weighing over 1 3 tonnes for the majority of ccbs their karstified appearance bears testimony to long periods of immobility since original deposition whilst their geomorphic settings on coastal slopes of coarse blocky talus is helpful in recognising lifting saltation as the probable mode of wave transport in the absence of local tsunamigenic potential these ccbs are considered to be prehistoric typhoon deposits presumably sourced from fringing coral reefs by high energy wave action application of existing hydrodynamic flow transport equations reveals that 4 7 m s and 7 1 m s are the minimum flow velocities required to transport 50 and 100 of the measured ccbs respectively such values are consistent with cyclone impacted coastlines studied elsewhere in the tropical asia pacific region overall the evidence of elevated carbonate boulder deposits on ko larn implies that typhoons before the modern record may have entered the bay of bangkok the recurrence of a similar event in future would have the potential to cause damaging marine inundation on surrounding low lying coastlines

shape evolution and fabric in a boulder beach monument cove maine abstract unequal spacing of nearly vertical joints and sheeting in hornblende granite at monument cove maine forms large tabular blocks which accumulate as talus on the backbeach the blocks are subsequently rounded by wave action to form a pocket boulder and cobble beach measurements of the talus blocks and boulders indicate that the initial structurally controlled bladed and elongate habits are manifested in the boulders however as abrasion progresses more compact spherical and more platy discoidal boulders evolve the data suggest that the greatest change is toward compactness and that the ultimate clast shape at monument cove would be spherical the orientations of the l i planes and the l axes of the rounded clases were also measured the l i planes are well oriented dipping m inly offshore the l axes orientations form three main clusters one subparallel to the shoreline one down the dip of the beach and one oblique to the shoreline the latter two clusters lie within the modal dip of the l i planes

sedimentology of rocky shorelines 4 coarse gravel lithofacies molluscan biofacies and the stratigraphic and eustatic records in the type area of the pleistocene hulopoe gravel lanai hawaii abstract during the pleistocene the south flank of lanai was the site of repeated erosion and deposition as a consequence of glacio eustasy superimposed on tectono isostasy throughout this time terrigenous and bioclastic gravel was generated along mainly rocky shorelines gravelly sediment was deposited in topographically low areas of the shoreface and inner shelf that later were uplifted isostatically the sedimentary lithofacies and biofacies in these deposits are distinctive but they represent a deposystem and suite of environments that hitherto have not been studied systematically these unrecognised circumstances have fuelled controversies about the nature and significance of the hulopoe gravel most notably the claim that it represents a mega tsunami deposit the hulopoe gravel in its type area displays a lithofacies succession that encompasses a complete disconformity bounded transgressive regressive cycle on a sand poor rocky shoreline this succession incorporates not only a distinctive vertical assemblage of rocky shoreline litho and biofacies but also internal disconformities that record episodes of erosion and non deposition during shoreline migration repetition of the lithofacies succession imparts overall stratigraphic order to the hulopoe gravel four unconformity bounded transgressive regressive cycles correspond to eustatic highstands of oxygen isotope stages 5 and 7 superimposed on continuing tectono isostatic uplift driven by growth of the island of hawaii this study of the hulopoe gravel demonstrates that the sedimentary record of mixed volcaniclastic carbonate depositional systems developed on rocky shorelines of tropical and subtropical oceanic island coasts can be preserved this record may include depositional products of both transgressive and regressive shorelines although tsunami and giant submarine landslides are known to occur in the hawaiian islands deposits and features that result from tsunami inundation above the shoreline such as might be expected from landslide related mega tsunami have not been recognised in the type area of the hulopoe gravel rocky palaeoshoreline records on oceanic volcanic islands may yield oceanographic and climatic clues that complement data obtained from other palaeoshoreline types

intertidal boulder based wave hindcasting can underestimate wave size evidence from yorkshire uk large boulder size clasts can represent important archives of high energy erosional wave activity at the coast from tropical coral reefs to high latitude eroding cliffs boulders have been used to hindcast the frequency and magnitude height of waves produced by both storms and tsunami such reconstructions are based on the balance between the hydrodynamic forces acting on individual boulders and the counteracting resistive forces of friction and gravity we test published models on over 900 intertidal boulders on the coast at staithes in north yorkshire u k using repeat high resolution topographic survey data we quantified the predicted versus actual rates of boulder movement in the field over a 7 year period 2007 2014 we assessed the degree to which local geomorphology and biology may affect the resistive forces inhibiting transport we found that 84 of intertidal boulders predicted to be mobile remained stationary over 7 years suggesting that in some contexts boulder movement may be significantly less than predicted regardless of boulder volume shape or location in situ cementation of boulders to the substrate by marine organisms appears to play a key role in retarding or preventing boulder transport the implication is that boulder characteristics may not always provide a reliable estimation of wave height on the coast and reliance solely on hindcasting relationships may result in under prediction of the frequency and magnitude of past storm wave activity we suggest here that more field studies that consider boulder movement are needed set within specific site contexts and that these data are used to improve the applicability and robustness of boulder transport models

bedrock sculpturing by tsunami south coast new south wales australia bedrock sculpturing resulting in s forms is associated with catastrophic flooding in near and subglacial environments produced by flow velocities approximating 10 m s 1 these velocities can also be produced by extreme tsunami generated by submarine landslides or comet impacts with oceans repetitive tsunami events during the late holocene have overwashed headlands along the new south wales south coast and produced two suites of bedrock sculptured terrain at the smaller scale s forms similar to muschelbruche v shaped grooves and sichelwannen have developed on upslopes while broad potholes flutes and transverse troughs have formed on headland crests cavitation features consisting of sinuous grooves impact marks drill holes and cavettos appear more ubiquitously at the larger scale stripped ramps large potholes cascade channels and canyon like features have been generated six flow phenomena mach stem waves jetting vortex impingement horseshoe vortices helical flow and multiple vor

early subduction related orogeny in the northern andes turonian to eocene magmatic and provenance record in the santa marta massif and rancheria basin northern colombia terra nova 23 26 34 2011 abstract the timing of orogeny in the northern andes and the mechanism driving it are still debated we have studied the age composition and provenance of granitoids and sandstones of the santa marta massif and rancheria basin northern colombia to relate deep seated and surface tectonic processes attending the late cretaceous palaeogene history of the northern andes our results indicate the development of five tectonic episodes 1 collision of northwestern south america with a 92 80 ma caribbean arc 70 ma 2 late collisional to early subduction metamorphism and magmatism 65 ma 3 distal accumulation of a thick siliciclastic sequence 60 58 ma 4 renewed arc magmatism 58 50 ma and 5 magmatic quiescence and block uplift post 50 ma the first episodes are related to the onset of subduction and the last episode is related to shallow subduction and oblique convergence similar events in colombia and ecuador reveal that the late cretaceous eocene orogeny of the northern andes was influenced by the collision and subduction of the caribbean oceanic plate

marine connections of amazonia evidence from foraminifera and dinoflagellate cysts early to middle miocene colombia peru abstract species composition in the present day amazonian heartland has an imprint of past marine influence the exact nature timing and extent of this marine influence however are largely unresolved here we use calcareous tests of foraminifera and marine palynomorphs from miocene sediments in northwestern amazonia to extend on current estimates for salinity ranges paleoenvironments and paleogeography our samples mostly contain tests and or organic linings of euryhaline tolerant to a wide range of salinity foraminifera of the genera ammonia trochammina and elphidium with ammonia being by far the dominant genus at all locations organic walled dinoflagellate cysts dinocysts such as spiniferites brigantedinium and tuberculodinium vancampoae are also common at a number of sites this association of foraminifera and dinocyst taxa points at varying salinities with aberrant forms of ammonia indicating lower limits of 0 10 psu practical salinity units whereas dinocyst associations suggest more marine conditions such regional heterogeneity is common at the interface of shallow marine to freshwater environments like estuaries we conclude that during the early and middle miocene marginal marine conditions reached at least 2000 km inland from the caribbean portal global high sea level and fast subsidence in the sub andean zone are thought to be the controlling mechanisms of the marine incursions lowering of global sea level and a change in tectonic regime terminated the incursions in the course of the plio pleistocene

extended equilibrium beach profiles abstract the idea of an equilibrium beach profile has been a useful concept in both theoretical and practical coastal engineering studies in essence the subject has thus far evolved to a choice of shape functions which are described by a small set of parameters additional efforts have attempted to relate these parameters to more fundamental quantities such as average grain size of the bottom sediment wave environment geometric aspects of the beach and the like this approach has a long history and can rightly claim a certain level of success however the usual collections of shape functions are well known to have difficulties very near the shoreline let alone on the nearshore portion of the beach this study extends the equilibrium profile up to and somewhat past the shoreline three shape functions are used in conjunction with a taylor expansion for the nearshore and above water portions of the profile a nonlinear fitting technique is applied to estimate the model s best parameter values moreover reduced versions of the proposed models can be employed for prediction based only on parameters related to sediment characteristics or wave conditions and geometry of the visible beach the approach is compared with data from the east coast of australia the east coast of north america and the south shore of the mediterranean sea

reassessment of hydrodynamic equations minimum flow velocity to initiate boulder transport by high energy events storms tsunamis abstract coastal boulders are good evidence of high energy events but the distinction between storm and tsunami boulders remains difficult to identify and mathematical models are still in their preliminary stages in a pioneering contribution nott 1997 2003 developed hydrodynamic equations to assess the minimum wave height required to initiate transport of a coastal boulder by tsunamis or storm surges these equations are widely cited and used but they can be improved in this study nott s equations have been revised 1 the equation for the submerged boulder scenario has been revised by rearranging the lift area of the lift force 2 the subaerial boulder scenario has been reconsidered by rearranging lift area and omitting inappropriate use of inertia force and 3 the joint bounded scenario was revised by balancing force components in the lifting direction and the effect of slope at the pre transport location is tested calculations are performed for four case studies boulders in western and eastern australia data after nott 1997 2003 boulders in southeastern italy data after scicchitano et al 2007 storm boulders in iceland data after etienne and paris 2010 and 2004 tsunami boulders in sumatra data after paris et al 2009 the minimum flow velocity required to initiate the transport of submerged boulders in the revised equation is less than that in nott s equation e g reductions up to 56 for submerged boulders and 65 for joint bounded blocks the minimum flow velocity required to initiate the transport of subaerial boulders from the revised equation also differed in comparison with nott s equation e g 4 22 for boulders detached from a seawall by the 2004 tsunami in sumatra while nott s equation was not applicable to some boulders e g beach rock boulders transported from the nearshore by the 2004 tsunami if we consider a joint bounded scenario for storm boulders in iceland the minimum flow velocity differs 43 to 41 from the results from nott s equation a boulder transport histogram is then introduced to represent the range of flow velocity that satisfies the requirements for initial transport of a boulder in different modes sliding rolling and saltation the boulder transport histogram can be used to predict the possible initial transport mode of a boulder from the flow velocity these theoretical results are compared to field data thus suggesting the initial transport mode of boulders and their pre transport locations the boulder transport histogram would be a valuable tool to reconstruct the magnitude of prehistoric high energy events such as tsunamis or storm surges in terms of flow velocity

tsunami sediments and their foraminiferal assemblages abstract tsunami hazard assessment begins with a compilation of past events that have affected a specific location given the inherent limitations of historical archives the geological record has the potential to provide an independent dataset useful for establishing a richer chronologically deeper time series of past events recent geological studies of tsunami are helping to improve our understanding of the nature and character of tsunami sediments wherever possible geologists should be working to improve the research tool kit available to identify past tsunami events marine foraminifera single celled heterotrophic protists have often been reported as present within tsunami deposited sediments but in reality little information about environmental conditions and by analogy the tsunami that deposited them has been reported even though foraminifera have an enormous capacity to provide meaningful palaeo environmental data here we review what foraminifera are describe their basic form and significance summarise where they have been reported in tsunami sediments and identify what can be learnt from them we review the gaps in our understanding and make recommendations to assist researchers who examine foraminiferal assemblages in order to enhance their use within tsunami geology

coupled tectonic evolution of andean orogeny and global climate abstract the largest tectonic relief breaking the earth s surface 13 km vertically is at the subduction margin of the andes which generates routinely megathrust earthquakes mw 8 5 and drives the paradigmatic andean orogen here we present key geologic evidence to reassess first order features of geomorphology and tectonics across the central andes where the orogen includes the altiplano plateau and attains its maximum integrated height and width the andean subduction margin has a stepped morphology dominated by the low relief atacama bench which is similar to a giant uplifted terrace slopes gently over a width of 60 100 km from the andes to the pacific and runs over more than 1000 km of coastal length we find that the genesis of stepped morphology at the andean seaboard is due to concomitant development of large west vergent thrusts parallel to the subduction interface and increasing aridity in the atacama desert which keeps an unprecedented large scale record of interplaying tectonics and cenozoic climate change incorporating our results with published geological knowledge demonstrates that andean orogeny is characterized by trench perpendicular bivergent and trench parallel bilateral growth over the past 50 myr associated with positive trench velocity toward the continent trench advance and subduction of a wide slab under south america we hypothesize that a global plate tectonic reorganization involving long lasting viscous mantle flow has probably forced both andean orogeny and global climate cooling since 50 ma in contrast two important stepwise pulses of increasing aridity and trench perpendicular andean growth appear to be results of changes in erosion rates due to global late eocene and middle miocene cooling events

grain shape analysis a new method for determining representative particle shapes for populations of natural grains abstract the size sorting and shape sorting of gravel bedload by running water often is investigated using identifiable tracer grains that represent the grains within the riverbed a new robust and reproducible method is described for the objective selection of three dimensional shapes that are representative of the variety of shape within any whole sample widespread adoption of the method would ensure comparability between the shape sorting results of different experiments the approach identifies average and extreme grain shapes from natural gravel samples importantly tracer dimensions are derived that form shapes with equal volume thus ensuring that the shape of the tracers is the only transport variable the method is tested on seven gravel samples from a range of fluvial beach and scree slope environments as well as different sieve sizes initially measurements of the short s intermediate i and long l orthogonal axes of clasts are made from selected sieve intervals that represent the spread in the size distribution of the natural gravel shapes are identified to be within the realms of the observed shapes of the sampled population four extreme shapes are identified a blade a rod a spheroid and a discoid as well as a median form the starting points of the analysis are the zingg ratios s i and i l however these quantities require polar coordinate transformation to be useful in shape selection the polar coordinate quantities form a joint probability density function that is the product of the marginal distributions of the new shape indices and the axes of the shape diagram utilizing and combining extreme percentiles of these latter distributions identifies the required shapes a reverse transformation returns these selected quantities back into zingg indices finally using the intermediate axial dimensions and the volume ratio the final tracer dimensions are found

boulder accumulations related to storms on the south coast of the reykjanes peninsula iceland coastal boulder accumulations are often mentioned in the literature even though their interpretation remains difficult especially along rock coasts affected both by storms and tsunamis studies on the geomorphic impact of such high energy events are actually of great interest since their intensity and frequency are key issues for the future evolution of coasts in the framework of the global change the southwest coast of iceland faces the powerful storms of the north atlantic ocean with wave heights of more than 15 m the probability for past and present tsunamis to hit this coast is very low in this paper we describe boulder accumulations along the volcanic rock coast of reykjanes southwest iceland they consist of cliff top boulders clusters and ridges beaches and boulder fields large boulders up to 70 t in weight have been transported and deposited up to 65 m inland 6 masl the maximum limit of boulder deposition and driftwood was found respectively 210 m and 550 m inland storms appear to be a predominant factor in the geomorphic evolution of reykjanes coasts our observations also give new insight for the interpretation of coastal boulder accumulations processes of erosion and deposition by tsunamis are a rising topic in the literature and the effects of recurrent and powerful storms are neglected

morphodynamics of a boulder beach putuo island se china coast the role of storms and typhoon abstract in this paper we examine the sedimentological properties and morphodynamic evolution of a boulder beach at huayanpeng cape on putuo island off the southeast china coast focus is given to the formation of the boulder beach 256 2000 mm diameter and resulting morphology in relation to high energy storms and seasonal typhoon holocene sea level rise to the present position at ca 7000 6000 yrs bp provides a long term window for the formation of the beach the beach is primarily characterized from east to west by 1 the convex to concave beach morphology 2 reduced longest axis of the skeleton boulders 3 decreased flatness of the skeleton boulders and 4 greater sphericity of the skeleton boulders infilling cobbles pebbles in the beach demonstrate a bi modal distribution corresponding to dominant sizes of 100 250 mm and 50 100 mm in diameter on the eastern beach and western beach respectively this reflects changed intensity of storm waves alongshore multiple peaks of the distributions of infilling clasts for the western beach supratidal probably reflect storm and calm weather sedimentation statistically both the skeleton boulders and infilling clasts follow a distribution reflecting the high energy control of beach formation and the dominance of crushing in boulder size reduction a boulder transport model applied in the present study further reveals that boulders with an a axis length of 500 1000 mm the dominant component on the beach move under a wide range of wave conditions depending on wave height and wave period with a cluster of critical wave heights in the range 2 6 m and wave periods of 5 15 s

tsunamis as geomorphic crises lessons from the december 26 2004 tsunami in lhok nga west banda aceh sumatra indonesia abstract large tsunamis are major geomorphic crises since they imply extensive erosion sediment transport and deposition in a few minutes and over hundreds of kilometres of coast nevertheless little is known about their geomorphologic imprints the december 26 2004 tsunami in sumatra indonesia was one of the largest and deadliest tsunamis in recorded human history we present a description of the coastal erosion and boulder deposition induced by the 2004 tsunami in the lhok nga bay located to the west of banda aceh northwest sumatra the geomorphological impact of the tsunami is evidenced by beach erosion some beaches have almost disappeared destruction of sand barriers protecting the lagoons or at river mouths numerous erosion escarpments typically in the order of 0 5 1 5 m when capped by soil and more than 2 m in dunes bank erosion in the river beds the retreat along the main river is in the order of 5 15 m with local retreats exceeding 30 m large scars typically 20 50 cm deep on slopes dislodgement of blocks along fractures and structural ramps on cliffs the upper limit of erosion appears as a continuous trimline at 20 30 m a s l locally reaching 50 m the erosional imprints of the tsunami extend to 500 m from the shoreline and exceed 2 km along riverbeds the overall coastal retreat from lampuuk to leupung was 60 m 550 000 m 2 and locally exceeded 150 m over 276 000 m 3 of coastal sediments were eroded by the tsunami along the 9 2 km of sandy coast the mean erosion rate of the beaches was 30 m 3 m of coast and locally exceeded 80 m 3 m the most eroded coasts were tangent to the tsunami wave train which was coming from the southwest the fringing reefs were not efficient in reducing the erosional impact of the tsunami the 220 boulders measured range from 0 3 to 7 2 m large typically 0 7 1 5 m with weights from over 50 kg up to 85 t we found one boulder less than 1 m large at 1 km from the coastline but all the others were transported less than 450 m 30 m and the moderate tsunamis height

miocene fish faunas from the northwestern amazonia basin colombia peru brazil with evidence of marine incursions new evidence indicates marine influences during the miocene in the northwestern amazonia basin this is the first major survey of the ichthyofauna from this area in the miocene fossil fish remains from taxa such as the dasyatoidea myliobatoidea characiformes siluriformes and sciaenidae are found conspicuous finds were two pharyngeal teeth of stephanodus minimus a species that so far had only ever been found in late cretaceous sediments the fish remains of freshwater brackish and marine taxa are deposited together throughout the area this is thought to be related to marine influences during the miocene these finds agree with earlier studies that suggest episodic marine influences which most likely lasted up to the late miocene and disagree with studies that suggest a connection between the atlantic and the caribbean sea over the south american continent the ichthyofaunas also indicate a warm climate as well as shallow and possibly torrential waters c 1998 elsevier science b v all rights reserved

rocky coasts their role as depositional environments abstract the role of rocky coasts as depositional environments has been generally neglected by rock and depositional coast workers although rock coasts can be hostile sedimentary environments they frequently host a variety of deposits consisting of mixes of boulders and megaclasts to sand and cobbles these deposits include pockets of sand and pebble trapped in topographic depressions or at the foot of scarps and cliffs isolated boulders pocket beaches trapped between headlands and sand to boulder beaches in shallow bays exposed to strong wave action the tectonic setting which is reflected in the degree of geological heterogeneity alongshore together with the wave regime and other elements of the morphogenic environment help to determine the amount and mobility of the sediment and consequently whether it plays an essentially abrasional or protectional role many beaches have a resistant rock foundation which will modulate their response to rising sea level and possibly increased storminess during this century wave refraction and temporal and spatial changes in sediment abrasional and protectional efficacy influence the development of crenulated planforms on coasts with a high degree of geological heterogeneity and possibly on more geologically homogeneous coasts with longshore variations in cliff height or in the amount of sediment theory suggests that these coasts may develop equilibrium planforms with uniform rates of erosion in bays and on headlands or they may undergo a series of cyclical transformations involving alternating increases and decreases in the depth of the bays relative to the headlands

large boulder accumulations by extreme waves along the adriatic coast of southern apulia italy abstract the adriatic coast of southern apulia italy is marked by the presence of large boulder accumulations boulders are up to 8 t in weight and arranged either in small groups or rows composed of a few imbricated elements the lower surface of some of the boulders is covered by biogenic encrustation which suggests that they were possibly carved from the mid or sublittoral zone and that they capsized during their transport other boulders detached from the supratidal zone have their surface affected by tilted rock pools new horizontal solution pans are continually forming a detailed survey of a large boulder accumulation was carried out at torre santa sabina direct observations were also made concerning the carving out and transportation of one single boulder during the severe storms in that area on january 4th 2002 and on january 12th 2003 collated data from both the survey and the direct observations including some radiocarbon age determinations and hydrodynamic calculations suggest that the studied accumulation was due to the superimposed effects of one or two tsunami as well as of storm waves tsunami would be responsible for the detachment and transportation of the largest boulders while storm waves may have been responsible for the carving out and transportation of the newer smaller blocks and for moving once again the largest boulders it was in this way that a typical boulder accumulation was produced the collated data suggest that two tsunami may have recently struck the adriatic coast of southern apulia the first possibly took place on the dalmatian coast as a result of the earthquake on april 6 1667 which destroyed ragusa modern day dubrovnik the second tsunami would have accompanied the strong earthquake which took place in southern apulia on february 20 1743