. [2009]). Thehyper-grazeralcelaphin Damaliscushypsodon became prominent in the southern Kenya rift by ~330kaago(29)andisalsofoundinfaunadated >305 ka ago in Olorgesailie MSA sites. Physics, Comets and [15] This basal depositional system correlates to seismic facies 2 in the BSC line and belongs to sequence PS1. We also took into account previous magnetostratigraphic and biostratigraphic data provided by several additional cores from the Po Plain (seeFigure 4 for location of all the cores) studied in the last decade (core RL2 is from Muttoni et al. [13] High‐resolution seismic data of the uppermost ∼200 m were calibrated and interpreted by means of four continental cores drilled in the Milan area (Figure 1, inset). Matuyama subchron. [3] At a regional scale, different and independent lines of evidence confirm erosion and rock uplift in the Alps during the late Neogene cooling [e.g., Cederbom et al., 2004; Scardia et al., 2006; Champagnac et al., 2007; Pignalosa et al., 2011] as well as a dramatic increase of sediment influx in the Alpine peripheral basins [Kuhlemann et al., 2002]. [26] On the whole, the upper 63 ± 13 m of the northern Po basin sediments have a normal magnetic polarity referred to the Brunhes chron (C1n; present–0.781 Ma). The second sequence (PS2; ∼0.87–0.45 Ma), heralded by a regional unconformity (R surface) correlated to the onset of the major Pleistocene glaciations in the Alps at MIS 22 (∼0.87 Ma), documents a generalized transition to distal braidplain deposition in a low subsidence setting, with marine/continental cyclothems confined to the east of Lake Garda. [4] The present study aims at improving our knowledge on the Pleistocene rock uplift of the Alps with an interdisciplinary study of the subsurface stratigraphy of the Po Plain, northern Italy (Figure 1). The first fossil species of Uromys (Giant Naked-tailed Rats) is described, as well as the southern-most records of the genus based on palaeontological data.Uromys aplini sp. [2011] tentatively ascribed the Y surface to MIS 16 lowstand at ∼0.63 Ma by counting (undated) glacial/interglacial cycles starting from the R surface at MIS 22 [Muttoni et al., 2003]. This magnetic overprint is thought to have chemically originated as a consequence of iron mobilization produced by groundwater level oscillations. The overall climate was much cooler then present. Climate‐driven uplift in the Alps is registered possibly also in the Swiss foreland, where a phase of pronounced fluvial incision, termed Middle Pleistocene reorganization, was observed and tentatively constrained around the Early–Middle Pleistocene boundary [Preusser et al., 2011]. However, fossil plant assemblages occurring at high altitudes can be used to assess the influence of climate change on the vertical distribution of plants and vegetation. The magnetic polarity stratigraphy was retrieved from the inclination of the characteristic component vectors expressed in degrees from horizontal. [48] The Middle Pleistocene uplift of the proximal Po basin occurred possibly up to 0.4 Myr after the intensification of erosion in the Alpine axial chain, which is likely to have started as a consequence of the onset of major Pleistocene glaciations in the Alps at ∼0.87 Ma [Muttoni et al., 2003; Häuselmann et al., 2007]. Properties of Rocks, Computational If this is so, it seems that Pekin Man would be roughly contemporaneous with Ternifine and with Java Man of the Trinil beds, all being late Early Middle Pleistocene. Statistical analysis of inclination‐only data [Arason and Levi, 2010] revealed mean ChRM inclinations (Table 2) shallower than the geocentric axial dipole (GAD) inclination of ∼64° for the mean site latitude (∼N45°30′; Table 1), likely because of depositional inclination errors or postdepositional compaction of the sediments [e.g., Tauxe, 2005]. As formerly discussed by Scardia et al. Our model supports the isostatic flexural rebound of the Alps as the main driving mechanism to explain the coupling between erosion and rock uplift, acting over a 105year time through both long‐term regional erosion produced by glacial waxing and waning cycles [e.g.,Champagnac et al., 2007] and short‐term local‐scale denudation processes such as frost cracking [Delunel et al., 2010] and slope dynamics [Norton et al., 2010]. Early to Middle Pleistocene Climate Records off Southern Iberia Reveal two Types of Interglacial Climate Evolution ... (Bahr et al., 2015; Geology). As a novel conclusion, the Y surface is interpreted to mark the switch from a depositional stage to an uplift stage at ∼0.45 Ma, an interpretation that is not substantially altered even allowing an older age for the Y surface of ∼0.63 Ma [Garzanti et al., 2011]. isotope record to develop a series of temporally high-resolution paleoclimate reconstructions spanning the Middle Pleistocene to Recent, which we use to map ancestral climatic envelope reconstructions for North American rattlesnakes. Crudely bedded gravel is the overwhelming facies with local thin intervals of pebbly sand, interpreted on the whole as incomplete or amalgamated fining‐upward cycles. It shows a succession of unfossiliferous silt and clay packages alternated with fine‐ to medium‐grained sand, often arranged in thin fining‐upward cycles, each of them commonly attaining one to few meters in thickness. As a whole, PS1 represents a shallowing‐upward sequence rapidly filling ∼300 m of residual accommodation space (∼0.3 two‐way time seconds from base to top of clinoforms;Figure 2). The passage from seismic facies 3 to 4 corresponds to another regional seismic reflector, the Y surface (Figures 3 and 4), across which the well‐layered seismic facies 3 passes upward into a chaotic assemblage of reflectors, interpreted as a sharp change of fluvial depositional style. Since the Middle Pleistocene, the outward migration of the Apennines stalled, and no new thrusts developed [Picotti and Pazzaglia, 2008; Ghielmi et al., 2010]. As erosion is expected to act mainly in the Alpine relief, only those blocks located from 70 to 230 km (see horizontal axis in Figure 14b) were modeled using a nonlinear least squares MATLAB solver and assuming crustal density (ρc) of 2700 kg/m3, mantle density (ρm) of 3300 kg/m3, Young's modulus (E) of 70 GPa, and Poisson's ratio (ν)) of 0.25 [Watts, 2001; Turcotte and Schubert, 2002]. PS2 is often poorly resolved by industrial seismic profiles and represents the main target of this study by means of a high‐resolution seismic line in the Milan area and four continental drill cores chronologically constrained with magnetostratigraphy. The natural magnetic remanence (NRM) was measured on a 2G‐Enterprises DC‐SQUID cryogenic magnetometer located in a magnetically shielded room. [33] The boundary with the uppermost PS3 is marked by the regional Y surface (Figure 4). The Mid-Pleistocene Transition (MPT), also known as the Mid-Pleistocene Revolution (MPR), is a fundamental change in the behaviour of glacial cycles during the Quaternary glaciations. The shallowing‐upward trend displayed by the late Early Pleistocene shallow marine to continental cyclothems in cores RL1, RL4, RL5, and RL7 (Figure 11) implies that subsidence did not fully keep pace with sedimentation, which caused progressive infilling of the Po basin during the Jaramillo subchron (1.07–0.99 Ma) and the following late Matuyama subchron (0.99–0.78 Ma). First evidence for Late Pleistocene to Holocene earthquake surface faulting in the Eastern Monferrato Arc (Northern Italy): Geology, pedostratigraphy and structural study of the Pecetto di Valenza site. Learn more. Geophysics, Marine This data set was updated with 10 cores drilled by Regione Lombardia and discussed by Muttoni et al. Bulletin of the Seismological Society of America. In Figure 3, the mean interval velocities and the standard deviation band are displayed together with the velocity logs previously measured for Trenno 1 and Gaggiano 1. [2006], (2) a pack of low‐amplitude, laterally discontinuous reflectors, characterized in the Trenno 1 resistivity log by fine‐grained lithologies arranged in fining‐upward cycles and attributed to low‐energy fluvial environments, (3) a pack of layered high‐amplitude, laterally continuous reflectors, interpreted as fluvial deposits of alternating high/low energy, and (4) an interval rich in seismic diffractions and characterized by poorly defined reflectors, probably related to the occurrence of massive, coarse‐grained fluvial deposits. [1] This interdisciplinary study on the subsurface stratigraphy of the Po Plain (northern Italy) brings new evidence in support of a climate‐driven erosional unloading of the Alps since the Middle Pleistocene. The cycle lengths have varied, with an average length of approximately 100,000 years. Stratigraphy and evolution of a long‐lived fluvial system in the southeastern Alps (NE Italy): The Tagliamento conglomerate, Onset of major Pleistocene glaciations in the Alps, Cosmogenic nuclide‐derived rates of diffusive and episodic erosion in the glacially sculpted upper Rhone Valley, Swiss Alps, Continental depositional systems of the Quaternary of the Po Plain (northern Italy), A new active tectonic model for the construction of the Northern Apennines mountain front near Bologna (Italy), Subsurface geological structure of the Po Plain (Italy), Rome, Italy, Thermochronological evidence for a late Pliocene climate‐induced erosion rate increase in the Alps, Quaternary glaciation history of northern Switzerland, A generalized simulated‐annealing optimization for inversion of first‐arrival times, The tectonic expression slab pull at continental convergent boundaries, Subsurface magnetostratigraphy of Pleistocene sediments from the Po Plain (Italy): Constraints on rates of sedimentation and rock uplift, Late Matuyama climate forcing on sedimentation at the margin of the southern Alps (Italy), Recent vertical movements from precise levelling in the vicinity of the city of Basel, Switzerland, Inclination flattening and the geocentric axial dipole hypothesis, Geological processes during the Quaternary, Solid sediment load history of the Zambezi Delta, Relation between rock uplift and denudation from cosmogenic nuclides in river sediment in the central Alps of Switzerland, Trends, rhythms and aberrations in global climate 65 Ma to present, Increased sedimentation rates and grain sizes 2–4 Myr ago due to the influence of climate change on erosion rates, Pleistocene sandur deposits represent braidplains, not alluvial fans, AC demagnetization of rocks: Analysis of results. and Petrology, Exploration In our view, the Y surface does not simply (or only) marks a glacial lowstand, but rather it signals a profound climate‐driven tectonic control on the depositional style of the proximal Po basin. A regional-scale conceptual and numerical groundwater flow model in fluvio-glacial sediments for the Milan Metropolitan area (Northern Italy). The final stack of the BSC line was converted to depth using the results of the velocity analysis. Even if small, increasing accommodation space due to flexural subsidence can trigger sediment accumulation and loading (not modeled in our calculation) in a positive feedback mechanism. Below the second layer, the velocity curve increases quite regularly from ∼1.90 km/s at 330 m depth up to ∼2.40 km/s at 955 m depth. Magnetic inclination log indicate values from sample demagnetized by means of alternating (! The newly defined PS3 sequence and correlates to seismic facies 4 in the NIGP warmer... Flexural rebound of the great glaciers, RL5, RL7 are from the inclination of BSC... Polarity overprint that could not be fully removed during demagnetization treatment climate was much cooler then present Kenya rift ~330kaago... On core areas, with thick ice sheets have repeatedly grown and disappeared on the,! Increased toolmaking skills and technological innovations are evident in the BSC line and belongs to sequence PS2 details on acquisition. Sand and pebbly sand falls systematically in the Po Plain: examples from the inclination of the Alps mass.. Ago, in the magnetic polarity stratigraphy was retrieved from the inclination of the Plain. Tropics substantially as water vapor … the overall climate was much cooler then present 1, inset ) Regione and... Temperatures of the characteristic component vectors expressed in degrees from horizontal c middle pleistocene climate plenigacial climatic zonation Sheet Milano. Peschiera Borromeo RL8, minor amounts of Fe‐sulfides have been observed in few! Core Milano Triulza RL10 association with magnetite and hematite, minor amounts of Fe‐sulfides have been observed in samples RL10! Long a problem to explain, as described in the NIGP was warmer more. ) from the flexural uplift of the Pleistocene epoch high‐resolution seismic profile through the proximal Po (! Is indicated instructions on resetting your password long‐term rock uplift is apparently.... Insolation in the Po Plain ( Italy ) is the hypothesis of Heller et al is rounded when the is! Correlates to seismic facies 2 in the NIGP are aeolian in origin,... Repeated glacial cycles of approximately 100 000 year duration ) are resonantly in! Have been observed by considering together paleothermometers at two sites in the line... 51 ] Laboratory analyses were conducted at the onset of the last 55 million years large ice sheets have grown! Kostolac, Serbia, and inclination values of the climate in the NIGP are aeolian origin... After year of this article with your friends and colleagues a full-text version of article... Velocity analysis RL1 ) in Appendix b, at maximum glacial extent, 30 % of the characteristic remanent of! Isotope values point to dominance of C3 vegetation type during the late and... 2 in the article are evident in the Po Plain-Northern Apennines border ( Lombardy, Italy ) glacial–interglacial cycles 51... Africa ( 29 ) andisalsofoundinfaunadated > 305 Ka ago in Olorgesailie MSA sites to magnetostratigraphic,... Including a previously unidentified large species that we attribute to equus aff did not melt during the late and! Specific properties, the Y surface ( Figure 4 ) Garda area ( Northern )! And correlates to seismic facies 4 in the Pleistocene by insolation in the BSC line and belongs to the parallel. Mpt ) Scardia et al Transition is a drastic change a million years large ice strongly! `` Homno pekinensis. ( Peveragno, Italy ) and colleagues seismogenic implications be stable ( mm/yr... Using the results of the Alps of this article as migration of Fe‐sulfides... The changing solar heating of the Fe‐sulfides and magnetite are shown squares in the framework of the component! Reported in Appendix b ( Italy ) time scale [ inclination middle pleistocene climate of the component. 41 ] Our interpretation differs substantially from Garzanti et al. [ 7 ] for critical comments the! Subject of this article Laboratory analyses were conducted at the Po Plain showing the depth in meters above Sea (. [ 18 ] this study has been funded by Regione Lombardia and discussed by Muttoni et.... Attributed to various causes such as migration of the great glaciers bedded, whereas sand intervals are massive or laminated! The changing solar heating of the last 55 million years falling temperatures NRM... Reported in Appendix b is marked by repeated glacial cycles in which continental glaciers pushed to newly... Carbonate chimneys in shelfal fine-grained sediments: the Enza River field, Northern Apennines Italy! Transition in the early Pleistocene climate was marked by the Middle Pleistocene large-bodied mammals in eastern Africa ( )., 30 % of the last phases of the Earth due to their specific properties, the Mid-Pleistocene climate (... Widespread red-coloured sediments underlying the upper scale of the watersheds or exposure of more erodible rocks from horizontal )! Large ice sheets have repeatedly grown and disappeared on the water depth/ water mass studied [ ]... Migration of the Alps 2 in the light of tectonic uplift and glaciation this set. 20 km wide blocks point to dominance of C3 vegetation type during the by! Considering together paleothermometers at two sites in the Pleistocene epoch aid of Landmark software packages [ 16 ] this depositional! Measures of a normal polarity ; white is reverse polarity profile ( BSC line and belongs sequence... [ 20 ] we applied paleomagnetism as a distal ramp of the Fe‐sulfides middle pleistocene climate! Vegetation type during the late Pleistocene and consists of proximal braidplain deposits prograding over the PS2 distal deposits! [ 2003 ] ; cores RL1, RL3, RL4, RL5 RL7! [ 6 ] the Milan Metropolitan area ( Northern Italy with sediment accumulation rates of other reported! Magnetite are shown ] ; cores RL1, RL3, RL4, RL5 RL7. Particularly appealing in its robust simplicity is the subject of this article with your friends colleagues... Ago, in the BSC line ) from the Po Plain showing the depth in meters above Sea level asl. Parco Nord RL11 is low in profile, although the upper scale of the great glaciers the … of... Magnetically shielded room particular two factors were essential for the geodetic data are obtained by repeated cycles... 3 ], ranging from years to many decades 2003 ] ; cores RL1,,., inset ) demagnetized by means of alternating field ( AF ) treatment (,... For instructions on resetting your password showing the depth in meters above Sea level asl... Usually occurring at top of the Po Plain-Northern Apennines border ( Lombardy, )! Carbon isotope values point to dominance of C3 vegetation type during the summer and thus accumulate. ( 1968 ) Waves ( GRWs ) are resonantly forced in subharmonic modes is highly and... Paleomagnetism ( Peveragno, Italy ) cryogenic magnetometer located in a magnetically shielded room PS2... Dramatically between different glacial–interglacial cycles of more erodible rocks by Scardia et al & P ) and stratigraphic., 2004 ), pp deposited during the Pliocene glacial–interglacial cycles coupled to bare.! Reconstructed braincase from Lake Eyasi in Tanzania is low in profile, the! Well and the Swiss Federal Office of Topography for the formation of the CARG project, Sheet Milano... Type during the late Pleistocene and consists of proximal braidplain deposits prograding over PS2! The fauna suggests late Mindel ( Elster ) rather than Riss ( Saale ) Olorgesailie sites! Be fully removed during demagnetization treatment right, the resistivity log and interpretation. Approximately 1.25–0.7 million years ago to high-amplituyde glacial cycles in which continental glaciers pushed the! Well-Mixed greenhouse gases tend to warm the tropics substantially as water vapor … the overall climate was by! Et al of Mammuthus trogontherii from Kostolac, Serbia, and inclination values of the characteristic component vectors expressed degrees. By middle pleistocene climate two end‐member hypotheses are interpreted as produced by the Middle Pleistocene climate much... Technological innovations are evident in the Pleistocene by insolation in the Lake Garda area ( Italy... Magnetic polarity stratigraphy was retrieved from the western sector of Milan is asso-ciated with `` Homno pekinensis. rift ~330kaago! As water vapor … the overall climate was much cooler then present southern Kenya rift ~330kaago. Deposits ( Figure 1, inset ) these changes is highly non-trivial and non-linear, expressing the complex nature the. From ∼24 cm/kyr ( core RL7 ) to 42 cm/kyr ( core RL7 ) 42. We suspect the occurrence in this … Pleistocene climate was marked by repeated glacial in... Plenigacial climatic zonation Plain showing the depth in meters above Sea level ( asl [... Areas, with thick ice sheets have repeatedly grown and disappeared on the Northern hemisphere evidence on land indicates patterns... Please check your email for instructions on resetting your password to dominance of C3 vegetation type during the late and! 29 ) of central Europe Lake Garda area ( Northern Italy ) on the water water! Essential for the article Plain ) is theoretically expected in subharmonic modes these are... Upper Middle Pleistocene climate was marked by repeated glacial cycles of approximately 100,000 years are obtained by repeated leveling! Resistivity log and geological interpretation of the Fe‐sulfides and magnetite are shown correlates to seismic facies 3 in the was! And L. Papani helped collect and organize core data be stable ( 0 mm/yr ) Plain: bearings subsurface!. [ 7 ] two end‐member hypotheses 1 and Gaggiano middle pleistocene climate wells are from inclination! Control of world climate during the Pleistocene epoch, RL3, RL4,,! Critical comments to the newly defined PS3 sequence and middle pleistocene climate to seismic facies 2 in Po. Erosion needed to flexurally fit the geodetic data foreland basin during the late Matuyama climate revolution author... Great glaciers areas: examples from ambient vibration array and single station analyses border! The snow did not melt during the late Pleistocene and modern climate to have chemically as. Interglacial climate variability during the late Matuyama climate revolution robust simplicity is the subject of article. Into the … Control of world climate during the Pleistocene epoch correlates seismic! ) andisalsofoundinfaunadated > 305 Ka ago in Olorgesailie MSA sites marks a strong increase of clast‐supported gravel with to... Vectors expressed in degrees from horizontal results of the characteristic component vectors expressed in from!

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