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Detailed geological mapping, morphostratigraphic, palaeontological and geochronological (uranium-series) analyses were undertaken on the raised marine terraces and interbedded terrestrial deposits along the Spanish peninsular and insular Atlantic and Mediterranean coasts. Several sets of Pleistocene shallow-marine to coastal deposits exposed in a staircase arrangement are interpreted as being emplaced during sea-level highstands coeval with interglacials or interstadials correlating with marine Oxygen Isotopic Stages (OIS) 5a/5c, 5e, 7, 9/11 and older. Up to three highstands have been identified in deposits formed during OIS 5e. Close to the end of OIS 5e there is a record of sudden changes in sea-surface conditions and climate marked by the disappearance of a major proportion of the warm 'Senegalese' fauna, switches from oolitic to non-oolitic facies, and accumulation of boulder beaches. Dating of the coral Cladocora caespitosa, found in a layer that also contains Strombus bubonius, confirms the occurrence of warm fauna in the Mediterranean basin during OIS 7, as previously suggested by Hillaire-Marcel et al. (1986), Goy et al. (1986a,b), Zazo and Goy (1989). Also the occurrence of warm faunas in deposits corresponding to an older interglacial, probably OIS 9 or 11, in the Balearic Islands suggests similar oceanographic conditions (sea-surface temperature, assuming constant salinity) during the last interglacial and at least two interglacials of the Middle Pleistocene in the western Mediterranean. ß

Uncertainty about the geological processes that deposited syngenetically frozen ice‐rich silt (yedoma) across hundreds of thousands of square kilometres in central and northern Siberia fundamentally limits our understanding of the Pleistocene geology and palaeoecology of western Beringia, the sedimentary processes that led to sequestration of hundreds of Pg of carbon within permafrost and whether yedoma provides a globally significant record of ice‐age atmospheric conditions or just regional floodplain activity. Here, we test the hypotheses of aeolian versus waterlain deposition of yedoma silt, elucidate the palaeoenvironmental conditions during deposition and develop a conceptual model of silt deposition to clarify understanding of yedoma formation in northern circumpolar regions during the Late Pleistocene. This is based on a field study in 2009 of the Russian stratotype of the ‘Yedoma Suite’, at Duvanny Yar, in the lower Kolyma River, northern Yakutia, supplemented by observations that we have collected there and at other sites in the Kolyma Lowland since the 1970s. We reconstruct a cold‐climate loess region in northern Siberia that forms part of a vast Late Pleistocene permafrost zone extending from northwest Europe across northern Asia to northwest North America, and that was characterised by intense aeolian activity. Five litho‐ and cryostratigraphic units are identified in yedoma remnant 7E at Duvanny Yar, in ascending stratigraphic order: (1) massive silt, (2) peat, (3) stratified silt, (4) yedoma silt and (5) near‐surface silt. The yedoma silt of unit 4 dominates the stratigraphy and is at least 34 m thick. It is characterised by horizontal to gently undulating subtle colour bands but typically lacks primary sedimentary stratification. Texturally, the yedoma silt has mean values of 65 ± 7 per cent silt, 15 ± 8 per cent sand and 21 ± 4 per cent clay. Particle size distributions are bi‐ to polymodal, with a primary mode of about 41 μm (coarse silt) and subsidiary modes are 0.3–0.7 μm (very fine clay to fine clay), 3–5 μm (coarse clay to very fine silt), 8–16 μm (fine silt) and 150–350 μm (fine sand to medium sand). Semidecomposed fine plant material is abundant and fine in‐situ roots are pervasive. Syngenetic ice wedges, cryostructures and microcryostructures record syngenetic freezing of the silt. An age model for silt deposition is constructed from 47 pre‐Holocene accelerator mass spectrometry (AMS) 14C ages, mostly from in‐situ roots and from three optically stimulated luminescence (OSL) ages of quartz sand grains. The 14C ages indicate that silt deposition extends from 19 000 ± 300 cal BP to 50 000 cal BP or beyond. The OSL ages range from 21.2 ± 1.9 ka near the top of the yedoma to 48.6 ± 2.9 ka near the bottom, broadly consistent with the 14C age model. Most of the yedoma silt in unit 4 at Duvanny Yar constitutes cryopedolith (sediment that has experienced incipient pedogenesis along with syngenetic freezing). Mineralised and humified organic remains dispersed within cryopedolith indicate in...

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To evaluate the effect of reservoir flooding on carbon cycling over time, we studied sedimentary environments in three natural lakes that existed prior to impoundment and that have been incorporated in the larger lentic system of a 70-yr-old boreal reservoir in Quebec. Elemental and biomarker analyses were determined in all core intervals and three soil profiles to characterize source inputs of organic matter to sediments. Following impoundment, a twoto threefold increase in lignin concentrations (5 to 10-25 mg [10 g dry wt]Ϫ1 ) associated with similar decreases in selected terrigenous biomarker ratios (cinnamyl phenols : vanillyl phenols, C : V, 1.0-2.0 to 0.2-0.5; 3,5-dihydroxybenzoic acid : vanillyl phenols, 3,5-Bd : V, 0.2-0.5 to 0.1-0.2; and p-hydroxyl phenols : sum of vanillyl and syringyl phenols, P : [VϩS], 0.3-0.7 to 0.1-0.4) illustrate the effect of soil erosion and subsequent translocation of surface soil organic matter (SOM) to sedimentary deposits. Using a mixing model based on mass-normalized biomarker yields in identified surface and mineral soil end-members, we show that although the proportion of mineral-derived SOM predominates in the receiving sedimentary systems during preflooding conditions (97-99% of allochthonous inputs), translocated surface SOM increased in postflooding sediments to comprise up to 5-30% of the total allochthonous organic matter inputs. Using a similar quantitative mixing model based on elemental C and N contents in the autochthonous and the mixed allochthonous end-members, we estimated that concomitant to the redistribution of eroded soil organic matter, reservoir flooding induces a 1.5-to 2-fold increase in the fraction of autochthonous organic matter transferred to sedimentary environments of the reservoir. Results presented here suggest that reservoir flooding induces a change of state in lake systems that may perdure over time scales of decades to centuries.