Cal Years BP Research Articles

Late Quaternary climatic and environmental conditions of northern Spain: An isotopic approach based on the mammalian record from La Paloma cave

La Paloma cave (Asturias, northern Spain) stands out as one of the most notable prehistoric sites of the northern Iberian sector due to the richness of its archaeo-paleontological material, spanning a complete Magdalenian–Azilian sequence (~20,300–12,900calyears BP). The abundance, diversity and good preservation of mammalian remains make of La Paloma site an excellent location to characterize paleoclimatic, paleoecological and paleoenvironmental conditions from a biogeochemical standpoint. Stable isotope analyses performed on tooth enamel (δ13Cen, δ18OCO3, δ18OPO4) and bone collagen (δ13Ccoll, δ15N) of a suite of herbivore, carnivore and omnivore species did not yield significant variations across the stratigraphic sequence, likely pointing to prevalent and stable local conditions, with i) no major vegetation turnover, ii) maintenance of hydrological conditions, and iii) relatively constant soil activity, in spite of the synchrony of the La Paloma temporal context with global events, such as the end of the Last Glacial Maximum, the Heinrich Event 1 and the Bølling–Allerød oscillation. La Paloma δ13Cen and δ13Ccoll values are within the expected range for C3 mixed woodland–mesic C3 grassland conditions. Overall, bovids (large Bovidae, ibex and chamois) show higher δ13Cen, δ13Ccoll and δ15N values than cervids (red deer and roe deer), indicating a preference for more open environments in the former. Horse δ13C values are undistinguishable from those of red deer and point to a mixed-feeding behavior. Horse low δ15N values may be indicative of a diet with a low protein content. Bayesian mixing model results yielded differences in carnivore resource use, with wolf preying on all ungulates and red fox preferentially incorporating roe deer. Stable paleoenviromental conditions during the latest Pleistocene at the La Paloma area may have favored the persistence of a stable mammalian community structure, supporting the idea of the existence of refuge areas in the northern Iberian sector throughout the late Quaternary glacial–interglacial dynamics.

Marine-continental tephra correlations: Volcanic glass geochemistry from the Marsili Basin and the Aeolian Islands, Southern Tyrrhenian Sea, Italy

Major, minor and trace element analysis of volcanic glass in proximal and distal (<2mm) tephra deposits underpins tephrochronology. This approach has been tested in the Aeolian Islands and the Tyrrhenian Sea using juvenile clasts in pyroclastic fall and flow deposits. Geochemical data are used to link marine tephras in the Marsili Basin (core TIR2000-C01) to explosive eruptions of (1) Lipari (Monte Pilato; 776calAD); (2) Vulcano; and (3) Campi Flegrei (Soccavo 1; 11,915–12,721calyears BP). Whether a polymictic coarse grained volcaniclastic turbidite in the Marsili Basin originated from collapse on Salina remains unresolved because multi-elemental analysis raises doubt about the published correlation to the Pollara region.It is evident that correlation of proximal continental and distal marine tephras, at a high level of confidence, requires a full complement of major, minor and trace element data. In conjunction with considerations of the mineralogy and morphology of juvenile deposits these data help define petrological lineages such that precise provenance can be established. Whilst a precise proximal–distal match must be based on identical major, minor and trace element concentrations it is clear that resurgent activity from a single volcano can produce magmas with identical compositions. In such cases stratigraphic relationships must complement any geochemical study. Occasionally proximal stratigraphies may be unrepresentative of the complete eruptive history because of a lack of exposure due to burial by more recent effusive and explosive activity, or sector collapse which can remove vital stratigraphy particularly on volcanic islands.