Quaternary History Research Articles

Quaternary landscape history determines the soil functional characters of terroir

The soil functional properties that characterise the terroirs of a denomination of origin area are products and witnesses of the Quaternary events, natural and human induced, which occurred in that landscape. Knowing the Quaternary history can enhance the awareness of stakeholders about the possible environmental and economic losses that can derive from irrational soil management, which can lead to the worsening or loss of irreproducible soils of the best terroirs.In the ”Vino Nobile di Montepulciano” wine territory, a four-year research project was conducted on the relationships between the soil and the viticultural and oenological behaviour of the Sangiovese vine. The study soils of the Montepulciano vineyard ranged notably in fertility conditions and functional characters, even when formed on the same kind of sediments. The grape production and vintage, as well as the organoleptic characteristics of the wine, depended on the kind of soil. The wines obtained from a first group of soils had a good structure and typicity, but the stability of the wine’s sensorial profile from different vintages was low. A second group exhibited good structure, typicity, and a good stability of wine sensorial profile. A third group had the highest values of yield per vine, mean cluster weight, 100 berries weight and total acidity. Also, sugar content level and sugar accumulation rate were the lowest of all vineyards. Wines showed low structure, low typicity, and high astringency in all the years of the research.The oldest soils of the Montepulciano vineyard started their formation during the Pleistocene. During the middle Holocene, humans deeply influenced pedogenesis, but it is during the last 50 years that the intensity of anthropic action has reached its maximum. Pre-plantation activities of the new specialized vineyards upset the land. Where soils before vine plantation were deep and rather homogeneous, functional characters remained the same, whereas they changed significantly where soils were shallower. Shallow soils on marine clays, in particular, have been very vulnerable to change. The best soils for Nobile di Montepulciano wine production, that is, those belonging to the second group, were Pleistocene and Holocene paleosols, formed as a consequence of unique natural and human induced geomorphological events. Therefore, they should be considered as cultural heritages.

Post-Messinian drainage changes triggered by tectonic and climatic events (eastern Southern Alps, Italy)

The Messinian–Quaternary history of tectonic and climatic control on sedimentation in the eastern Southern Alps, northern Italy, was reconstructed using an integrated petrographic and sedimentological analysis of five sedimentary successions. These units mainly consist of fluvial conglomerates of the Tagliamento sequence, deposited within the eastern Southern Alps since the Upper Miocene (“Messinian Salinity Crisis”). At that time, the closure of marine gateways between the Atlantic Ocean and the Mediterranean Sea caused a drop in sea level, causing exchanged fluvial erosion and widening of the Alpine catchments. Sediment composition in the Upper Miocene to Lower Pliocene units shows an abrupt change in the source areas: from sediments characterized by carbonate rock fragments to detritus rich in low-grade metamorphic grains. In spite of tectonic activity within the eastern Southern Alps, no major modifications in sediment supply took place during the Pliocene–Early Pleistocene time span. In the Middle Pleistocene the first major expansion of the Alpine glaciers triggered a change in drainage patterns and a marked increase in erosion rates. Predominantly climatic control on sedimentation in the Tagliamento basin and the erosion of the Carnic Alps produced sediments rich in quartz, siltstone and metamorphic rock fragments, deposited in the Upper Pleistocene unit and in modern river sediments.

Age determinations for glacial Lake Agassiz shorelines west of Fargo, North Dakota, USA

Understanding the evolution of Lake Agassiz is vital to developing a comprehensive late Quaternary history of central North America. Although many of the geomorphic features of the lake are well kn...

Pliocene–Quaternary contourites along the northern Gulf of Cadiz margin: sedimentary stacking pattern and regional distribution

This study reports novel findings on the Pliocene–Quaternary history of the northern Gulf of Cadiz margin and the spatiotemporal evolution of the associated contourite depositional system. Four major seismic units (P1, P2, QI and QII) were identified in the Pliocene–Quaternary sedimentary record based on multichannel seismic profiles. These are bounded by five major discontinuities which, from older to younger, are the M (Messinian), LPR (lower Pliocene revolution), BQD (base Quaternary discontinuity), MPR (mid-Pleistocene revolution) and the actual seafloor. Unit P1 represents pre-contourite hemipelagic/pelagic deposition along the northern Gulf of Cadiz margin. Unit P2 reflects a significant change in margin sedimentation when contourite deposition started after the Early Pliocene. Mounded elongated and separated drifts were generated during unit QI deposition, accompanied by a general upslope progradation of drifts and the migration of main depocentres towards the north and northwest during both the Pliocene and Quaternary. This progradation became particularly marked during QII deposition after the mid-Pleistocene (MPR). Based on the spatial distribution of the main contourite depocentres and their thickness, three structural zones have been identified: (1) an eastern zone, where NE–SW diapiric ridges have controlled the development of two internal sedimentary basins; (2) a central zone, which shows important direct control by the Guadalquivir Bank in the south and an E–W Miocene palaeorelief structure in the north, both of which have significantly conditioned the basin-infill geometry; and (3) a western zone, affected in the north by the Miocene palaeorelief which favours deposition in the southern part of the basin. Pliocene tectonic activity has been an important factor in controlling slope morphology and, hence, influencing Mediterranean Outflow Water pathways. Since the mid-Pleistocene (MPR), the sedimentary stacking pattern of contourite drifts has been less affected by tectonics and more directly by climatic and sea-level changes.

The Calabrian Stage, Pleistocene highstand in Malta: a new marker for unravelling the Late Neogene and Quaternary history of the islands

Abstract: The Late Neogene and Quaternary sedimentary record within the Maltese islands is very fragmentary and has generally been ignored by sedimentologists. Local stratigraphies for parts of the Quaternary have been erected from vertebrate remains contained in Quaternary cave and fissure deposits of the islands. However, no coherent correlation scheme has been proposed in which to encompass them. The situation is exacerbated by the absence of datable fossils within the majority of Quaternary deposits. Considerable progress in resolving these problems is, however, possible if recourse is made to the post-Messinian (Late Miocene) erosion features evidenced in the topography of the islands. In particular, a hitherto unrecognized marine erosion surface, the San Leonardo Marine Abrasion Surface, is described and dated by reference to the marine deposits (San Leonardo Beds) lying directly above it and similarities to contemporaneous SE Sicily marine deposits. This provides an end-Calabrian Stage (Emilian Sub-Stage) base line upon which to hang fragmentary information on later events that have shaped the topography of the Maltese islands. From this it can be confirmed that a tectonic deformation event spanning latest Messinian to mid- Pliocene times uplifted the islands and reactivated previously incipient graben systems. This deformation episode is shown to have ceased within the islands well before the early Calabrian (before c . 1.6 Ma). Subsequent minor regional uplift and eustacy together with subaerial weathering processes have been the principal agents in shaping the islands. Collectively, these processes have prevented terrestrial animal migrations into the Maltese islands from North Africa since Messinian times. However, the infrequent re-establishment of a marine lowstand isthmus virtually linking Malta with SE Sicily has permitted opportunistic animal migrations into the islands and the presence of these greatly aids in dating the sedimentological events.

Global, regional and local scale factors determining glaciation extent in Eastern Siberia over the last 140,000 years

The aim of this work is to evaluate the effect of variations of greenhouse gas concentrations, orbital parameters, sea-surface conditions, vegetation and dust deposition on the extent of East Siberian mountain glaciations during the late Quaternary. An atmosphere-only general circulation model is used in a series of 16 sensitivity tests at high spatial resolution over the region of interest to systematically evaluate the relative importance of these different forcing parameters. No attempt was made to reproduce in detail the history of late Quaternary mountain glaciations in East Siberia, because, given (a) the temporal and spatial scarcity of available evidence of mountain glaciations in this region and (b) the large uncertainties concerning the boundary conditions to be prescribed in this model, such an exercise must necessarily remain incomplete and partially inconclusive. The results of this study suggest that moisture delivery from the Atlantic is an important factor determining mountain glacier mass balance in Eastern Siberia and is very sensitive to the geometry of the West Eurasian ice sheet. This means that variable moisture blocking by the West Eurasian ice sheet during the Weichselian is the most important single factor explaining the opposite history of glacier and ice sheet extent in West and East Eurasia during the Weichselian. This work confirms earlier results showing that the large 140 kyr BP West Eurasian ice sheet caused regional-scale cooling extending towards Eastern Eurasia. Nevertheless, the simulated response of the regional summer temperature (and thus glacier extent because of the strong dependency of glacier mass balance of summer melt rates) is to a very large extent directly determined by insolation. For the Early Weichselian, this leads to a clear maximum of local glacier extent at 70 kyr BP, which is in line with the variations of top-of-the-atmosphere insolation on orbital time scales, but to some degree at odds with geological evidence which suggests larger glacier extent at 115 and 90 kyr BP than at 70 kyr BP. Through snow feedbacks, the effects of changes in the prescribed vegetation distribution and dust deposition rate are also substantial. In summary, it appears that the broad features of late Quaternary glaciation history in Eastern Eurasia can be understood in terms of known forcings.

DISCUSSION OF MEGACLAST TRANSPORT AND EROSION OF ROCKY SHORELINES: A COMMENT ON WILLIAMS (2010)

DISCUSSION OF MEGACLAST TRANSPORT AND EROSION OF ROCKY SHORELINES: A COMMENT ON WILLIAMS (2010) JASPER KNIGHT A recent paper by Williams (2010) described very glacial sediment and/or preglacial weathered debris large boulders (megaclasts) from the Aran Islands, (Moles and Moles 2002). This variable sediment Galway Bay, and argued that wave overtopping of cover strongly influenced patterns of postglacial high cliffs caused clast detachment and landward weathering. Although the extent of glaciation on transport by wave bores. Here I highlight limita- the Aran Islands is unclear (McCarron 2007), tions of Williams's arguments, and show that clast glacially-influenced preconditioning of rock surfaces detachment and transport involves complex pro- through weathering is extremely significant but was cesses and conditions not considered in his paper. not considered by Williams (2010). Pre-detachment conditioning of rocky shorelines Processes of clast detachment It is important to consider clast properties (size, Williams (2010) was concerned with identifying shape, strength, lithology, degree of weathering) the wave height required for clast transport, but prior to considering processes of clast detachment did not first consider processes by which clasts and transport. This is because pre-detachment are detached from rockhead. Limestone weather history strongly influences clast susceptibility to ing decreases rock strength, widens joints and detachment (Naylor and Stephenson 2010), the force makes clasts more easily detachable. Recent studies required for detachment (Nott 2003), and processes show a close relationship between weathering, rock of clast transport (Goto et al. 2009). Williams strength, and likelihood of clast detachment (e.g. does not consider pre-detachment history, but it Hall et al. 2008; Naylor and Stephenson 2010). is significant for the Aran Islands because of its Williams (2010) assumes that all areas of the underlying Lower Carboniferous limestone. Weath- upper cliff face are potential sites for clast detach ering and karstification has led to joint widening ment. However, recent studies show that rocky and block déstabilisation, evidenced by surface shoreline erosion is highly selective, strongly litho grikes, karren and dolines and subsurface caves, logically controlled, and that clasts are detached The Quaternary history of the region is also sig- preferentially from the intertidal zone (Naylor and nificant. Frozen ground during glaciations allowed Stephenson 2010; Knight and Burningham 2011). meltwater erosion to cut channels and oversteepen Williams (2010) applied Nott's (2003) equation for slopes. Permafrost and meltwater erosion were joint-bounded blocks in calculating the significant both active in western Ireland during the late Mid- wave height required for clast detachment. However, landian glaciation (Orme 1967; Lewis 1985). Differ- Nott (2003) was concerned with sloping shore ential glacial erosion also led to exposure of some platforms rather than cliffs, and his equations have bedrock surfaces whilst others were protected by now been superseded (Nandasena et al. 2011). Irish Journal of Earth Sciences 29 (2011), 23-24 ■© 2011 Royal Irish Academy doi: 10.3318/IJES.2011.29.23 23 24 Irish Journal of Earth Sciences (2011) Wave conditions required for clast movement Williams (2010) argued that a landward-moving bore formed as a result of cliff overtopping by white- (broken) or green-water (unbroken) waves. Bores can only form where waves are topographi cally funnelled across a shore platform or cliff-top (Hall et al. 2008). No topography was presented by Williams, hence it is unclear if bores are likely or not. Williams' paper's title explicitly stated it would illustrate the storm versus tsunami wave debate, but failed to do that. Scheffers et al. (2010) presented radiocarbon ages from organics below megaclasts on the Aran Islands and County Clare. They showed clasts were emplaced episodically throughout the last 3,000 years and, although there may be correspondence with periods of high stormi ness (Hansom and Hall 2009), a tsunamigenic origin cannot be rejected. Knight and Burningham (2011) mapped the distribution of upper shoreface boulders in County Donegal and showed that, although clasts can be detached under contempor ary wave conditions, there is a mismatch between the size of contemporary clasts and those that form ridges on the shore platform. This suggests that a spectrum of past and present wave sizes and there fore wave-generating mechanisms are responsible for clast detachment and transport. JASPER KNIGHT School of Geography...

DISCUSSION OF MEGACLAST TRANSPORT AND EROSION OF ROCKY SHORELINES: A COMMENT ON WILLIAMS (2010)

DISCUSSION OF MEGACLAST TRANSPORT AND EROSION OF ROCKY SHORELINES: A COMMENT ON WILLIAMS (2010) JASPER KNIGHT A recent paper by Williams (2010) described very glacial sediment and/or preglacial weathered debris large boulders (megaclasts) from the Aran Islands, (Moles and Moles 2002). This variable sediment Galway Bay, and argued that wave overtopping of cover strongly influenced patterns of postglacial high cliffs caused clast detachment and landward weathering. Although the extent of glaciation on transport by wave bores. Here I highlight limita- the Aran Islands is unclear (McCarron 2007), tions of Williams's arguments, and show that clast glacially-influenced preconditioning of rock surfaces detachment and transport involves complex pro- through weathering is extremely significant but was cesses and conditions not considered in his paper. not considered by Williams (2010). Pre-detachment conditioning of rocky shorelines Processes of clast detachment It is important to consider clast properties (size, Williams (2010) was concerned with identifying shape, strength, lithology, degree of weathering) the wave height required for clast transport, but prior to considering processes of clast detachment did not first consider processes by which clasts and transport. This is because pre-detachment are detached from rockhead. Limestone weather history strongly influences clast susceptibility to ing decreases rock strength, widens joints and detachment (Naylor and Stephenson 2010), the force makes clasts more easily detachable. Recent studies required for detachment (Nott 2003), and processes show a close relationship between weathering, rock of clast transport (Goto et al. 2009). Williams strength, and likelihood of clast detachment (e.g. does not consider pre-detachment history, but it Hall et al. 2008; Naylor and Stephenson 2010). is significant for the Aran Islands because of its Williams (2010) assumes that all areas of the underlying Lower Carboniferous limestone. Weath- upper cliff face are potential sites for clast detach ering and karstification has led to joint widening ment. However, recent studies show that rocky and block déstabilisation, evidenced by surface shoreline erosion is highly selective, strongly litho grikes, karren and dolines and subsurface caves, logically controlled, and that clasts are detached The Quaternary history of the region is also sig- preferentially from the intertidal zone (Naylor and nificant. Frozen ground during glaciations allowed Stephenson 2010; Knight and Burningham 2011). meltwater erosion to cut channels and oversteepen Williams (2010) applied Nott's (2003) equation for slopes. Permafrost and meltwater erosion were joint-bounded blocks in calculating the significant both active in western Ireland during the late Mid- wave height required for clast detachment. However, landian glaciation (Orme 1967; Lewis 1985). Differ- Nott (2003) was concerned with sloping shore ential glacial erosion also led to exposure of some platforms rather than cliffs, and his equations have bedrock surfaces whilst others were protected by now been superseded (Nandasena et al. 2011). Irish Journal of Earth Sciences 29 (2011), 23-24 ■© 2011 Royal Irish Academy doi: 10.3318/IJES.2011.29.23 23 24 Irish Journal of Earth Sciences (2011) Wave conditions required for clast movement Williams (2010) argued that a landward-moving bore formed as a result of cliff overtopping by white- (broken) or green-water (unbroken) waves. Bores can only form where waves are topographi cally funnelled across a shore platform or cliff-top (Hall et al. 2008). No topography was presented by Williams, hence it is unclear if bores are likely or not. Williams' paper's title explicitly stated it would illustrate the storm versus tsunami wave debate, but failed to do that. Scheffers et al. (2010) presented radiocarbon ages from organics below megaclasts on the Aran Islands and County Clare. They showed clasts were emplaced episodically throughout the last 3,000 years and, although there may be correspondence with periods of high stormi ness (Hansom and Hall 2009), a tsunamigenic origin cannot be rejected. Knight and Burningham (2011) mapped the distribution of upper shoreface boulders in County Donegal and showed that, although clasts can be detached under contempor ary wave conditions, there is a mismatch between the size of contemporary clasts and those that form ridges on the shore platform. This suggests that a spectrum of past and present wave sizes and there fore wave-generating mechanisms are responsible for clast detachment and transport. JASPER KNIGHT School of Geography...

Cross-scale analysis of the region effect on vascular plant species diversity in southern and northern European mountain ranges.

BackgroundThe divergent glacial histories of southern and northern Europe affect present-day species diversity at coarse-grained scales in these two regions, but do these effects also penetrate to the more fine-grained scales of local communities?Methodology/Principal FindingsWe carried out a cross-scale analysis to address this question for vascular plants in two mountain regions, the Alps in southern Europe and the Scandes in northern Europe, using environmentally paired vegetation plots in the two regions (n = 403 in each region) to quantify four diversity components: (i) total number of species occurring in a region (total γ-diversity), (ii) number of species that could occur in a target plot after environmental filtering (habitat-specific γ-diversity), (iii) pair-wise species compositional turnover between plots (plot-to-plot β-diversity) and (iv) number of species present per plot (plot α-diversity). We found strong region effects on total γ-diversity, habitat-specific γ-diversity and plot-to-plot β-diversity, with a greater diversity in the Alps even towards distances smaller than 50 m between plots. In contrast, there was a slightly greater plot α-diversity in the Scandes, but with a tendency towards contrasting region effects on high and low soil-acidity plots.Conclusions/SignificanceWe conclude that there are strong regional differences between coarse-grained (landscape- to regional-scale) diversity components of the flora in the Alps and the Scandes mountain ranges, but that these differences do not necessarily penetrate to the finest-grained (plot-scale) diversity component, at least not on acidic soils. Our findings are consistent with the contrasting regional Quaternary histories, but we also consider alternative explanatory models. Notably, ecological sorting and habitat connectivity may play a role in the unexpected limited or reversed region effect on plot α-diversity, and may also affect the larger-scale diversity components. For instance, plot connectivity and/or selection for high dispersal ability may increase plot α-diversity and compensate for low total γ-diversity.

Late Quaternary slip rate on the Kern Canyon fault at Soda Spring, Tulare County, California

The Kern Canyon fault represents a major tectonic and physiographic boundary in the southern Sierra Nevada of east-central California. Previous investigations of the Kern Canyon fault underscore its importance as a Late Cretaceous and Neogene shear zone in the tectonic development of the southern Sierra Nevada. Study of the late Quaternary history of activity, however, has been confounded by the remote nature of the Kern Canyon fault and deep along-strike exhumation within the northern Kern River drainage, driven by focused fluvial and glacial erosion. Recent acquisition of airborne lidar (light detection and ranging) topography along the ∼140 km length of the Kern Canyon fault provides a comprehensive view of the active surface trace. High-resolution, lidar-derived digital elevation models (DEMs) for the northern Kern Canyon fault enable identification of previously unrecognized offsets of late Quaternary moraines near Soda Spring (36.345°N, 118.408°W). Predominately north-striking fault scarps developed on the Soda Spring moraines display west-side-up displacement and lack a significant sense of strike-slip separation, consistent with detailed mapping and trenching along the entire Kern Canyon fault. Scarp-normal topographic profiling derived from the lidar DEMs suggests normal displacement of at least 2.8 +0.6/–0.5 m of the Tioga terminal moraine crest. Cosmogenic 10Be exposure dating of Tioga moraine boulders yields a tight age cluster centered around 18.1 ± 0.5 ka ( n = 6), indicating a minimum normal-sense fault slip rate of ∼0.1–0.2 mm/yr over this period. Taken together, these results provide the first clear documentation of late Quaternary activity on the Kern Canyon fault and highlight its role in accommodating internal deformation of the southern Sierra Nevada.

Nature and Genesis of Till Silt Pellets from the Shuanghu Area, Central Tibetan Plateau, China

Distinctive silt pellets were identified in a diamicton profile, 1 km north of the town of Shuanghu on the central Tibetan Plateau. The characteristics (mineral composition, texture, structure, fabric, and striations) of the diamicton indicate that it was formed under ice as subglacial melt-out or lodgment till. Comparing the shape, size, grain composition, and preservation of the pellets in this area with published pellet studies, we conclude that silt pellets from the Shuanghu area are formed by in situ melting out of dead ice (containing pellets) within subglacial till. We estimate that the till was deposited no later than Marine Isotope Stage (MIS) 8, based on nearby numerical ages for post-glacial fluvial terraces and the overall Quaternary glaciation history of the Tibetan Plateau. This is the first time that silt pellets have been identified in glacial deposits on the Tibetan Plateau. Detailed examination of the characteristics and formation of silt pellets has the potential to provide new insight into the basal condition of paleo-glaciers on the Tibetan Plateau.

Preliminary estimate of Holocene slip rate on active normal faults bounding the southern coast of the Gulf of Evia, central Greece

We investigate the late Quaternary history of slip on the Kamena Vourla and Arkitsa normal faults, which are segments of a fault system bounding the south coast of the Gulf of Evia in central Greece, and which we refer to as the Coastal Fault System. We examine two river terraces, near the village of Molos, which are found within the uplifted footwall of the Kamena Vourla fault. The upper terrace is ~20 m above the present river level and appears to represent fan deposition into the main river channel from surrounding tributaries. The lower terrace, ~8 m above the present-day river bed, represents an interval of river-bed aggradation and correlates with the surface of a delta on the hanging-wall side of the fault. GPS profiles show a 6 ± 0.1 m vertical offset of the lower terrace surface as it crosses the fault. Preliminary dating of the two terrace levels, using both optical luminescence and radiocarbon methods, provides inconclusive results. The lower terrace, however, grades toward the present-day sea level and correlates with the surface of a delta on the hanging-wall side of the fault; it is, therefore, likely to date from ~6 ka, when sea level stabilized at its present-day highstand. With an age of ~6 ka, the 6 m vertical displacement of the lower terrace yields an estimate of ~1.2-2.0 mm/yr for the Holocene rate of slip across the Kamena Vourla fault. This rate of slip is comparable with an estimated rate of ~0.7-2.0 mm/yr for the central (Arkitsa) segment of the Coastal Fault System, and with a 0.4-1.6 mm/yr slip rate measured on the easternmost (Atalanti) segment. These estimates of Holocene slip rates are consistent with the 1-3 mm/yr of present-day extension across the Gulf of Evia measured by GPS, arguing against large changes in rate of extension through the Holocene. Both the Arkitsa and Kamena Vourla faults are clearly active and despite an absence of historical earthquakes on either fault, they should be considered to be a major hazard to local populations. However, further dating studies and palaeoseismic investigations are required before the slip rate and history can be fully quantified.

New results on palaeoenvironmental conditions in equatorial Africa derived from alluvial sediments of Cameroonian rivers

The ReSaKo project undertook extended fieldwork across southern Cameroon to explore the palaeoenvironmental information recorded in the alluvial sediments of equatorial African rivers. 160 hand-corings reaching maximum depths of 550 cm were carried out on alluvial ridges and floodplains of major Cameroonian fluvial systems. These multilayered, sandy to clayey alluvia contain sedimentary form-units and palaeosurfaces, which provide excellent additional proxy data archives for the reconstruction of palaeoenvironmental conditions in western equatorial Africa. Coring transects and sedimentary profiles document grain-size shifts and distinguishable sedimentary units in the stratigraphic record, which evidence (fluvial-)morphological adjustments of the fluvial systems in response to external forcing and (river-) intrinsic variability. 76 14C-(AMS)-dated samples from organic sediment and macro-rests (fossil organic remains like wood, leafs, etc.) embedded in these sedimentary units indicate Late Pleistocene to recent ages (uncalibrated 14C-ages: 48–0.2 ka BP). The tentative interpretation of the alluvial record yields excellent additional information on the complex feedbacks between climate, ocean, fluvial as well as ecological systems and human activity in a little-studied region with high sensitive tropical ecosystems. δ 13C-values (−35.5 to −18.0‰) of the dated samples indicate the persistence of C 3-dominated gallery forests across the rivers (‘fluvial rain forest refuges’) despite several climatic fluctuations (aridifications, e.g. Last Glacial Maximum around 20 ka BP, Younger Dryas 13–11 ka BP). This research complements earlier results from additional terrestrial and marine proxy data archives on the Late Quaternary history of monsoonal western equatorial Africa.

The role of topography in structuring the demographic history of the pine processionary moth, Thaumetopoea pityocampa (Lepidoptera: Notodontidae)

AbstractAim We investigated the Quaternary history of the pine processionary moth, Thaumetopoea pityocampa, an oligophagous insect currently expanding its range. We tested the potential role played by mountain ranges during the post‐glacial recolonization of western Europe.Location Western Europe, with a focus on the Pyrenees, Massif Central and western Alps.Methods Maternal genetic structure was investigated using a fragment of the mitochondrial cytochrome c oxidase subunit I (COI) gene. We analysed 412 individuals from 61 locations and performed maximum likelihood and maximum parsimony phylogenetic analyses and hierarchical analysis of molecular variance, and we investigated signs of past expansion.Results A strong phylogeographic pattern was found, with two deeply divergent clades. Surprisingly, these clades were not separated by the Pyrenees but rather were distributed from western to central Iberia and from eastern Iberia to the Italian Peninsula, respectively. This latter group consisted of three shallowly divergent lineages that exhibited strong geographic structure and independent population expansions. The three identified lineages occurred: (1) on both sides of the Pyrenean range, with more genetically diverse populations in the east, (2) from eastern Iberia to western France, with a higher genetic diversity in the south, and (3) from the western Massif Central to Italy. Admixture areas were found at the foot of the Pyrenees and Massif Central.Main conclusions The identified genetic lineages were geographically structured, but surprisingly the unsuitable high‐elevation areas of the main mountainous ranges were not responsible for the spatial separation of genetic groups. Rather than acting as barriers to dispersal, mountains appear to have served as refugia during the Pleistocene glaciations, and current distributions largely reflect expansion from these bottlenecked refugial populations. The western and central Iberian clade did not contribute to the northward post‐glacial recolonization of Europe, yet its northern limit does not correspond to the Pyrenees. The different contributions of the identified refugia to post‐glacial expansion might be explained by differences in host plant species richness. For example, the Pyrenean lineage could have been trapped elevationally by tracking montane pines, while the eastern Iberian lineage could have expanded latitudinally by tracking thermophilic lowland pine species.

An International Debate on the Status of the Quaternary as a Formal Chronostratigraphical Unit and the Final Ratification of the Quaternary System/Period

The term Quaternary' has been widely used in the Earth Sciences,representing the youngest time span in the geological history of the Earth. Quaternary research has attracted much attention as it is one of the most important scientific fields for understanding global environmental change. However,a long-running debate over both the status of the Quaternary as a formal chronostratigraphical unit and its base ( 1. 8 Ma versus 2. 6 Ma) has existed since the coining of the term in the 18th century. In 2004,the term Quaternary' was even abandoned by some famous scholars and organizations,leading to a heated international debate. Finally in 2009,a proposal for establishing Quaternary as a formal international Period/System with its base at 2. 6 Ma was formally ratified by the International Union of Geological Sciences. Here we first review the history of the term Quaternary',and then celebrate the historic contribution which the Chinese loess community have made in the effort to retain the term Quaternary' and to assign it a formal rank in the Geologic Time Scale.

Late Quaternary history of the Kap Mackenzie area, northeast Greenland

Wagner, B., Bennike, O., Cremer, H. & Klug, M. 2010: Late Quaternary history of the Kap Mackenzie area, northeast Greenland.Boreas, Vol. 39, pp. 492–504. 10.1111/j.1502‐3885.2010.00148.x. ISSN 0300‐9483.The Kap Mackenzie area on the outer coast of northeast Greenland was glaciated during the last glacial stage, and pre‐Holocene shell material was brought to the area. Dating of marine shells indicates that deglaciation occurred in the earliest Holocene, before 10 800 cal. a BP. The marine limit is around 53 m a.s.l. In the wake of the deglaciation, a glaciomarine fauna characterized the area, but afterc. one millennium a more species‐rich marine fauna took over. This fauna includedMytilus edulisandMysella sovaliki, which do not live in the region at present; the latter is new to the Holocene fauna of northeast Greenland. The oldestM. edulissample is dated toc. 9500 cal. a BP, which is the earliest date for the species from the region and indicates that the Holocene thermal maximum began earlier in the region than previously documented. This is supported by driftwood dated toc. 9650 cal. a BP, which is the earliest driftwood date so far from northeastern Greenland and implies that the coastal area was at least partly free of sea ice in summer. As indicated by former studies, the Storegga tsunami hit the Kap Mackenzie area atc. 8100 cal. a BP. Loon Lake, at 18 m a.s.l., was isolated from the sea atc. 6200 cal. a BP, which is distinctly later than expected from existing relative sea‐level curves for the region.

Glacial populations and postglacial migration of Douglas-fir based on fossil pollen and macrofossil evidence

To understand how temperate forests might respond to future episodes of global warming, it is important to study the effects of large-scale climate change brought about by rapid postglacial warming. Compilations of fossil evidence have provided the best evidence of past plant range shifts, especially in eastern North America and Europe, and provide a context for interpreting new molecular datasets from modern forests. In western North America, however, such reviews have lagged even for common, widespread taxa. Here, we synthesize fossil evidence for Douglas-fir ( Pseudotsuga menziesii) from nearly 550 fossil pollen, sedimentary macrofossil, and packrat midden macrofossil sites to develop hypotheses about the species’ late Quaternary history that can be tested with molecular phylogeographic studies. For both the coastal and interior varieties, we identified alternative hypotheses on the number of glacial populations and postglacial migration patterns that can be characterized as single-population versus multiple-population hypotheses. Coastal Douglas-fir may have been subdivided into two populations at the Last Glacial Maximum (LGM) and colonized British Columbia from populations in Washington and Oregon. Interior Douglas-fir could have been subdivided along major topographic barriers into at least three LGM populations and colonized British Columbia and Alberta from populations in northwest Wyoming and/or northeast Utah. For both varieties, we calculated migration rates lower than previous studies, which could have been as high as 100–220 m/yr if Douglas-fir reached its modern distribution 9000 cal yr BP, or as low as 50 m/yr if it reached its modern range at present. The elevational range of populations in California and the southern Rockies shifted upslope by 700–1000 m. If there were multiple LGM populations, these elevational shifts suggest that those populations did not contribute to the colonization of Canada. Our findings emphasize the possibility of low-density northern LGM populations and that populations within species react individualistically in response to large-scale climate change.

Facilitating Progress on the Quaternary History of Sea Level Change: Understanding Future Sea Level Rise: The Challenges of Dating Past Interglacials; Woods Hole, Massachusetts, 20–25 September 2009

Substantial uncertainty exists in projections of future sea level rise, due primarily to a lack of understanding about ice sheet dynamics. Paleo Constraints on Sea Level Rise (PALSEA) is a working group of the Past Global Changes (PAGES) project and the International Marine Global Change Studies (IMAGES) program that aims to extract information bout ice sheet response to temperature change by examining the history of sea level over the Quaternary (spanning the past ∼2.5 million years). In particular, PALSEA focuses on the past 800,000 years, particularly interglacial periods, with a range of temperatures bracketing the modern.

The Norwegian reference lake ecosystem, Øvre Heimdalsvatn

The subalpine lake, Ovre Heimdalsvatn and its catchment, situated in the mountains of southern Norway, has been the subject of extensive ecosystem studies over the last 50 years covering a wide range of disciplines. The lake is located at 1,088 m a.s.l., has an area of 0.78 km2, a maximum depth of 13 m, and a catchment area of 23.6 km2. It lies more or less on the limit of the birch forest, while the catchment extends up over 1,800 m a.s.l. and into the high alpine zone. The valley is little influenced by human activity and there is no permanent habitation, although the area is used for grazing of domestic livestock during summer. Otherwise the lake and its catchment have always been important for fish and game. The catchment also received major radionuclide fallout from the Chernobyl accident in 1986. The studies include Quaternary history, the development of algorithms for remote sensing of snow conditions, long-term changes in lake ice cover and temperature, the zooplankton and benthic communities, as well as the uptake of Chernobyl radionuclides and mercury by the biota. The consequences of the introduction of the European minnow (Phoxinus phoxinus) on the benthos, zooplankton and the brown trout (Salmo trutta) have also been investigated. The lake and its catchment are widely used in university teaching and thesis work. On account of the substantial knowledge base, Ovre Heimdalsvatn is well suited to long-term monitoring.

The Late Pleistocene–Holocene climate history in the western Todzha basin ( Eastern Tuva)

The Late Quaternary history of climate and deposition environments in the western Todzha basin has been reconstructed from the respective lacustrine and fluvial deposits. Data from sedimentary sections have provided clues to the causes and timing of sudden deposition changes, including those associated with Holocene tectonic activity in the Taskyl fault. Especially informative are permafrost, diatom, spore-pollen, and tree-ring data from a section at the Merzly Yar locality where frozen ground has preserved the pristine rhythmic pattern of sediments. The Merzly Yar section stores a record of dramatic consequences of large earthquakes generated by the fault which produced a large damlake. The revealed pattern of discontinuous limnic deposition, with prominent tree markers and syngenetic ice wedges, places exact constraints on the stratigraphy of the section and allows its correlation with Holocene climate events within the intervals of fossil soils and vegetation.