Abstracts / Quaternary International 279-280 (2012) 9–120 19

regional climates, whereas their comparison suggests broader NorthPacific atmospheric circulation patterns and shifts. The Jellybean Lake d18Orecord is 7500 years long and d18O variations are interpreted as degree offractionation during moisture transport from the Gulf of Alaska controlledby the intensity and position of the Aleutian Low. An intensified/eastwardAleutian Low is thought to correspond with lower d18O values, and viceversa. The Bison Lake d18O record is 10,000 years long and d18O variationsare interpreted as seasonal precipitation balance controlled by winterPacific storm tracks. Drought periods (i.e. drier winters and/or a more rain-dominated seasonal precipitation balance) generally correspond withhigher d18O values, and vice versa. Comparisons with marine proxy dataalong the northeast Pacific margin are used to evaluate the hypothesis thatclimate patterns along the North American cordillera reflect changes inPacific climate patterns such as ENSO and the PDO.

ENVIRONMENTAL EVOLUTION OF THE MIRA ESTUARY (SWPORTUGUESE COAST) IN THE LATE QUATERNARY

César Andrade. Centro de Geologia, Faculdade de Ciências da Unive, PortugalE-mail address: candrade@fc.ul.pt

The Mira River outlets in the SW coast of Portugal, 120km south of Lisbon.It flows SE-NW for 140km before abruptly bending westwards in itsterminal 5km. A number of sediment-choked flat-floored stream valleysmeeting the main valley, together with expansions of tidal flats/saltmarshes at the river margins constitute excellent sedimentary archiveswith potential to unravel the Pleisto-Holocene environmental evolution ofthis region. Three cores were drilled in these sediments (MA – Moinho daAsneira salt marsh, 3.5km landward of the coast, north margin of the mainstream; CP – Corgo do Porto, 4km upcoast, alluvial plain of a tributary;VN1-Ch – salt marsh 5km upstream, south margin of the main stream) andstudied for palaeoenvironmental proxies (sedimentology, geochemistry,micropalaeontology) and dated using 14C.Cores CP, 27m-long, and VN1-Ch, 43m-long, correspond to Holocene andUpper Pleistocene sediments directly resting upon Palaeozoic basement;MA core is 5.5m long and sampledmaterials accumulated from 5500 cal BPonwards. Results and interpretation of the studied proxies allowedrecognizing the signal of the Holocene transgression in all cored areas,represented by a thick sequence of organic and bioclastic mud deposits,covering Pleistocene high-energy fluvial materials. The transgressivesediments settled in estuarine and progressively more open marineenvironments, until a transgressive maximum detected around 6000 calBP at CP, after 4500-4000 cal BP at VN1-Ch and 2700 cal BP at MA. The agedifferences correspond to contrasting elevations of the surfaces drowned.Following this maximum, a forced regression is recorded in all sites, theterrestrialization corresponding to the establishment of an alluvial plain atCP and of marginal salt marsh expansions at MA and VN1-Ch.

LATE PLIOCENE/EARLY PLEISTOCENE ENVIRONMENTS OF THESIBERIAN ARCTIC INFERRED FROM THE LAKE EL'GYGYTGYN POLLENRECORD

Andrej Andreev. University of Cologne, Institute of Geology and Mi, GermanyE-mail address: aandreev@awi-potsdam.de

Continuous sequences that penetrates the entire Quaternary and furtherinto the Pliocene is highly desired from the terrestrial Arctic. Such a recordhas now become available from Lake El’gygytgyn located in northeasternSiberia. The lake lies within a meteorite impact crater in Chukotka (NERussia, 67�30' N, 172�05' E). The crater was created nearly 3.6 Million yearsago in volcanic target rocks. The impact formed an 18-kilometer-wide holein the ground that then filled with water. The retrieved lake sediments aretrapped pollen from a several thousand square-kilometer source areaproviding reliable insights into over-regional millennial-scale vegetationand climate changes of the Arctic since the Pliocene. The international’’El’gygytgyn Drilling Project“ of ICDP has completed three holes in thecentre of the lake penetrating about 311 m thick lake sediments and about200 m of the impact rocks below. The lowermost 200 m of the lacustrinesediments have been studied for pollen. The record documents palae-oenvironmental and palaeoclimatic changes during the Late Pliocene andtransition to the Early Pleistocene. The revealed pollen assemblages can be

subdivided into 10 pollen zones. The Pliocene pollen assemblages are so fardominated mostly by tree pollen. Repeated changes in the plant assem-blages through time reflect variations in forests of pine, larch, spruce, fir,alder, and hemlock. The tree pollen significantly decreases during thepresumed Kaena subchron (3.1-3.03 Ma), concomitant with an increase inthe relative abundance of wormwood pollen, spores of rock spike-moss,and coprophilous fungi. This pollen composition suggests treeless glacialenvironments, which can be described as tundra-steppe. The Pliocene/Pleistocene transition (2.5 Ma) is broadly marked in the widely spacedsamples studied so far by a distinct change from predominantly coniferousassemblages to pollen spectra dominated by dwarf birch, shrub alder, andherbs.

A REVISION OF THE CAPRINAE (BOVIDAE, MAMMALIA) FROM THEPLIO-PLEISTOCENE OF SPAIN

María Andrés. Departamento de Ciencias de la Tierra-IUCA, Univer, SpainE-mail address: mandresr@unizar.es

Sheep and goats and their relatives (Caprinae) are an important compo-nent of the mammalian faunas from Eurasia since the Late Pliocene. Today,the Caprini are the most abundant caprines in Eurasia, but during thePliocene they were the Ovibovini. Nevertheless, caprines are scarcelyfound in Plio-Pleistocene fossil sites. Because of this, the intraspecificmorphological variability is unknown and the taxonomic determination isdifficult in many cases. Furthermore, systematics and phylogenetic rela-tionships of these taxa have been controversial and are still unclear. Thus,some authors consider Megalovis latifrons, Hesperidoceras merlae andPliotragus ardeus closely related forms that could well constitute a singlespecies or evolving lineage and Kabulicornis ahmadi would be an earlierrelative form of them.

Hesperidoceras merlae is a quite rare bovid only found in Spain, in partic-ular in the Late Pliocene site of Villarroya. The only taxonomical study ofthis species was made by Villalta and Crusafont Pairo (1953), whichincluded the skull and the teeth. However, the postcranial elements havenever been studied. Here, we examine new material from the Villarroyafossil site and compared it with the related Plio-Pleistocene ovibovinesabove mentioned. The morphometric analyses (bivariate and principalcomponent analyses) carried out on teeth and postcranial elements revealclear differences among all the species. Our conclusions on the systematicsand relationships of these species indicate that Pliotragus ardeus andHesperidoceras merlae are not synonymous species. Current knowledgepoints out that Capra or closest relatives were not present in IberianPeninsula until the Pleistocene.

A LATE QUATERNARY HISTORY OF COASTAL PLAIN DEVELOPMENTRECORDED IN PALAEOSOLS AND SEDIMENTARY SUCCESSIONS

Stefano Andreucci. University of Sassari, ItalyE-mail address: sandreucci@uniss.it

Alluvial fans combine palaeosol conservation, outcrop access, andextended time intervals. On the other hand, they host potentially ambig-uous palaeosol outcrops; pedocomplexes are the norm, and nature andposition of stratigraphic boundaries cannot be taken for granted. Then,palaeosol research greatly benefits from detailed stratigraphic analysiswhich, in turn, greatly benefits from palaeopedology. Absolute dating isa requirement for solving stratigraphic ambiguities, even before it isneeded for placing the record in its context.Alluvial fans in coastal settings are a link between marine and terrestrialenvironments. The Cecina valley (Tuscany) Pleistocene succession is a largesediment body recording a long-term sea level regression. The successionevolves from a fluvio-deltaic to an alluvial fan environment, and the upperportion was focused by our research. Integration of field skills was neededto reconstruct key surfaces. Back-to-back detail assessment of inconsis-tencies in soil profiles and facies overcame ambiguities. The successionrecords the transition from alluvial-fan conglomerate, from poorlyconfined, sediment-laden, flows, to channel-fill conglomerate, sandstoneand mudstone. The latter attest to a fan entrenchment, within a long-termtelescopic progradation driven by surface uplift and sea level changes. Fan