Southeastern Po Plain Research Articles

Vegetation height and structure drive foraging habitat selection of the lesser kestrel (Falco naumanni) in intensive agricultural landscapes.

Habitat selection in animals is a fundamental ecological process with key conservation implications. Assessing habitat selection in endangered species and populations occupying the extreme edges of their distribution range, or living in highly anthropized landscapes, may be of particular interest as it may provide hints to mechanisms promoting potential range expansions. We assessed second- and third-order foraging habitat selection in the northernmost European breeding population of the lesser kestrel (Falco naumanni), a migratory falcon of European conservation interest, by integrating results obtained from 411 direct observations with those gathered from nine GPS-tracked individuals. The study population breeds in the intensively cultivated Po Plain (northern Italy). Direct observations and GPS data coincide in showing that foraging lesser kestrels shifted their habitat preferences through the breeding cycle. They positively selected alfalfa and other non-irrigated crops during the early breeding season, while winter cereals were selected during the nestling-rearing phase. Maize was selected during the early breeding season, after sowing, but significantly avoided later. Overall, vegetation height emerged as the main predictor of foraging habitat selection, with birds preferring short vegetation, which is likely to maximise prey accessibility. Such a flexibility in foraging habitat selection according to spatio-temporal variation in the agricultural landscape determined by local crop management practices may have allowed the species to successfully thrive in one of the most intensively cultivated areas of Europe. In the southeastern Po Plain, the broad extent of hay and non-irrigated crops is possibly functioning as a surrogate habitat for the pseudo-steppe environment where most of the European breeding population is settled, fostering the northward expansion of the species in Europe. In intensive agricultural landscapes, the maintenance of alfalfa and winter cereals crops and an overall high crop heterogeneity (deriving from crop rotation) is fundamental to accommodate the ecological requirements of the species in different phases of its breeding cycle.

Earthquakes and depleted gas reservoirs: which comes first?

Abstract. While scientists are paying increasing attention to the seismicity potentially induced by hydrocarbon exploitation, so far, little is known about the reverse problem, i.e. the impact of active faulting and earthquakes on hydrocarbon reservoirs. The 20 and 29 May 2012 earthquakes in Emilia, northern Italy (Mw 6.1 and 6.0), raised concerns among the public for being possibly human-induced, but also shed light on the possible use of gas wells as a marker of the seismogenic potential of an active fold and thrust belt. We compared the location, depth and production history of 455 gas wells drilled along the Ferrara-Romagna arc, a large hydrocarbon reserve in the southeastern Po Plain (northern Italy), with the location of the inferred surface projection of the causative faults of the 2012 Emilia earthquakes and of two pre-instrumental damaging earthquakes. We found that these earthquake sources fall within a cluster of sterile wells, surrounded by productive wells at a few kilometres' distance. Since the geology of the productive and sterile areas is quite similar, we suggest that past earthquakes caused the loss of all natural gas from the potential reservoirs lying above their causative faults. To validate our hypothesis we performed two different statistical tests (binomial and Monte Carlo) on the relative distribution of productive and sterile wells, with respect to seismogenic faults. Our findings have important practical implications: (1) they may allow major seismogenic sources to be singled out within large active thrust systems; (2) they suggest that reservoirs hosted in smaller anticlines are more likely to be intact; and (3) they also suggest that in order to minimize the hazard of triggering significant earthquakes, all new gas storage facilities should use exploited reservoirs rather than sterile hydrocarbon traps or aquifers.

Detecting discontinuities in GNSS coordinate time series with STARS: case study, the Bologna and Medicina GPS sites

Global navigation satellite systems (GNSS) data are a fundamental source of information for achieving a better understanding of geophysical and climate-related phenomena. However, discontinuities in the coordinate time series might be a severe limiting factor for the reliable estimate of long-term trends. A methodological approach has been adapted from Rodionov (Geophys Res Lett 31:L09204, 2004; Geophys Res Lett 31:L12707, 2006) and from Rodionov and Overland (J Marine Sci 62:328–332, 2005) to identify both the epoch of occurrence and the magnitude of jumps corrupting GNSS data sets without any a priori information on these quantities. The procedure is based on the Sequential t test Analysis of Regime Shifts (STARS) (Rodionov in Geophys Res Lett 31:L09204, 2004). The method has been tested against a synthetic data set characterized by typical features exhibited by real GNSS time series, such as linear trend, seasonal cycle, jumps, missing epochs and a combination of white and flicker noise. The results show that the offsets identified by the algorithm are split into 48 % of true-positive, 28 % of false-positive and 24 % of false-negative events. The procedure has then been applied to GPS coordinate time series of stations located in the southeastern Po Plain, in Italy. The series span more than 15 years and are affected by offsets of different nature. The methodology proves to be effective, as confirmed by the comparison between the corrected GPS time series and those obtained by other observation techniques.

A Combination of Space and Terrestrial Geodetic Techniques to Monitor Land Subsidence: Case Study, the Southeastern Po Plain, Italy

The southeastern Po Plain is affected by high natural and anthropogenic subsidence. The area is well suited to test the application of an observational strategy which combines different techniques to extract information on the spatial and temporal variability of the subsidence. The simultaneous availability, at a few stations, of several geodetic observation techniques such as Global Positioning System (GPS), gravity, and Interferometric Synthetic Aperture Radar (InSAR) allows for validation of the individual time series. The combination takes advantage of the complementary strengths of each technique by overcoming the limitations inherent in each single technique alone. The combination of velocities derived from the GPS and gravity data, further complemented by the results of the InSAR Permanent Scatterers technique, allows us to monitor continuously, in space and time, vertical crustal movements. This high‐density information is of major importance for understanding the processes responsible for the observed deformation. Here long‐term trends were derived, enabling us to map the behavior of subsidence (even exceeding 20 mm/yr) with high spatial resolution in the southeastern Po Plain. The uplifting behavior of the Apennines chain bordering the Po Plain is identified together with a narrow zone separating the contrasting vertical crustal movements.

Millennial-scale depositional cycles from the Holocene of the Po Plain, Italy

The Holocene depositional history of southeastern Po Plain on time scales of 10 3 yr is reconstructed, based upon integrated sedimentological and micropalaeontological analyses of nine continuously-cored boreholes, about 40 m deep. Major palaeoenvironmental changes include the rapid landward migration of a barrier-estuary–lagoon system during the Early–Middle Holocene (transgressive systems tract—TST), followed by extensive delta progradation in the last 6000 yr (highstand systems tract—HST). Detailed facies analysis of cores combined with the identification of 12 microfossils (benthic foraminifer and ostracod) associations allow an ultra-high-resolution sequence–stratigraphic framework to be reconstructed. Particularly, eight small-scale, high-frequency cycles, about 3–5 m thick and spanning intervals of time of about 1000 yr, can be physically traced throughout the study area. Interpretation of these cycles, which are invariably bounded by sharp flooding surfaces and generally show internal shallowing-upward trends (parasequences), indicates that relative sea-level changes during the Holocene were episodic and punctuated by rapid phases of sea-level rise, followed by periods of stillstand (or decreasing sea-level rise). From seaward to landward locations, parasequence boundaries document beach-barrier migration, bay-head delta abandonment and increasing accommodation in the coastal plain. The ensuing phases of sea-level stillstands resulted in the progressive filling of the newly formed accommodation space, through beach progradation, extensive mud deposition in behind-barrier lagoonal (estuarine) and marsh deposits, and aggradation in bay-head delta systems at the head of estuaries. Eustacy appears to be the major controlling factor of the retrogradational stacking pattern of parasequences within the TST. By contrast, a complex interplay of eustacy, sediment supply and subsidence, with an increasing influence of autocyclic mechanisms, such as channel avulsion and delta lobe abandonment, controlled facies architecture within the HST. The maximum flooding surface cannot be assumed to be synchronous, its timing being strongly dependent upon local variations in sediment influx and subsidence. This study shows that the micropalaeontologic characterization of mud-prone (coastal plain and estuarine) successions in terms of water depth and salinity can lead to very accurate sequence–stratigraphic interpretations, allowing identification of parasequence boundaries that may not be detected by conventional stratigraphic approach.

Benthic foraminiferal associations from Upper Quaternary deposits of southeastern Po Plain, Italy

Research Article| January 01, 2004 Benthic foraminiferal associations from Upper Quaternary deposits of southeastern Po Plain, Italy Flavia Fiorini Flavia Fiorini Dipartimento di Scienze della Terra e Geoloico-Ambientali, Università di Bologna, Via Zamboni 67, 40127 Bologna, Italy email: fiorini@geomin.unibo.it Search for other works by this author on: GSW Google Scholar Micropaleontology (2004) 50 (1): 45–58. https://doi.org/10.2113/50.1.45 Article history received: 05 Apr 2003 accepted: 30 Oct 2003 first online: 06 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Flavia Fiorini; Benthic foraminiferal associations from Upper Quaternary deposits of southeastern Po Plain, Italy. Micropaleontology 2004;; 50 (1): 45–58. doi: https://doi.org/10.2113/50.1.45 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyMicropaleontology Search Advanced Search Abstract Quantitative analysis of benthic foraminifers from three continuously-cored boreholes (130m deep) at different distances from the Adriatic coast and focused within two marine intervals (0–30m and 100–120m depth) that on the basis of AMS 14C dating and pollen data are assigned to oxygen isotope Stage 1 and Substage 5e, respectively, has revealed seven foraminiferal associations. Associations Me (Textularia spp. and Miliolidae) and Md (Miliolidae, Elphidium spp. and Cribroelphidium spp.) are characteristic of infralittoral environments. Associations Mb (Ammonia tepida, A. parkinsoniana and Cribroelphidium spp.) and Ma (Ammonia tepida and A. parkinsoniana) are indicative of shallow-marine environments influenced by freshwater. Reworked and transported microfaunal association Rm corresponds to supralittoral environments (beach-ridge deposits). Associations Bd-b (Ammonia tepida, A. parkinsoniana and brackish ostracods) and Ba (Trochammina inflata) are characteristic of bay, lagoon and estuary environments.Comparison of benthic foraminiferal associations from coeval deposits provides information on the relative distance of cores from the Holocene and Tyrrhenian paleo-shorelines. Core 205-S10 is characterised by deeper marine associations than core 223-S12. Core 240-S13 contains exclusively associations characteristic of lagoonal and brackish marsh environments.Vertical variation in microfaunal associations within each marine deposit reveal in both intervals a transgressive trend, followed upwards by a regressive trend. Benthic foraminiferal associations from cores 205-S10 and 223-S12 show that the Tyrrhenian maximum flooding surface corresponds to a deeper marine environment than peak transgression in the Holocene. This is also shown by core 240-S13, where an open lagoonal microfauna characterizes Tyrrhenian deposits and a brackish marsh association marks the Holocene sediments. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Benthic foraminiferal associations from Upper Quaternary deposits of southeastern Po Plain, Italy

Quantitative analysis of benthic foraminifers from three continuously-cored boreholes (130m deep) at different distances from the Adriatic coast and focused within two marine intervals (0–30m and 100–120m depth) that on the basis of AMS 14C dating and pollen data are assigned to oxygen isotope Stage 1 and Substage 5e, respectively, has revealed seven foraminiferal associations. Associations Me (Textularia spp. and Miliolidae) and Md (Miliolidae, Elphidium spp. and Cribroelphidium spp.) are characteristic of infralittoral environments. Associations Mb (Ammonia tepida, A. parkinsoniana and Cribroelphidium spp.) and Ma (Ammonia tepida and A. parkinsoniana) are indicative of shallow-marine environments influenced by freshwater. Reworked and transported microfaunal association Rm corresponds to supralittoral environments (beach-ridge deposits). Associations Bd-b (Ammonia tepida, A. parkinsoniana and brackish ostracods) and Ba (Trochammina inflata) are characteristic of bay, lagoon and estuary environments.Comparison of benthic foraminiferal associations from coeval deposits provides information on the relative distance of cores from the Holocene and Tyrrhenian paleo-shorelines. Core 205-S10 is characterised by deeper marine associations than core 223-S12. Core 240-S13 contains exclusively associations characteristic of lagoonal and brackish marsh environments.Vertical variation in microfaunal associations within each marine deposit reveal in both intervals a transgressive trend, followed upwards by a regressive trend. Benthic foraminiferal associations from cores 205-S10 and 223-S12 show that the Tyrrhenian maximum flooding surface corresponds to a deeper marine environment than peak transgression in the Holocene. This is also shown by core 240-S13, where an open lagoonal microfauna characterizes Tyrrhenian deposits and a brackish marsh association marks the Holocene sediments.

Influence of glacial cycles and tectonics on natural subsidence in the Po Plain (Northern Italy): Insights from 14C ages

Samples rich in organic matter were collected from boreholes in the southern part of the Po Plain (Italy), a rapidly subsiding sedimentary basin. New 14C dates, obtained from these samples, and 14C data from the literature allowed for the evaluation of the rates of natural subsidence in the area. These range from 0 to 5 mm/yr. Most areas show rates around 1 and 2 mm/yr. The obtained subsidence rates are comparable with burial rates obtained from archaeological data. These data are interpreted in terms of long‐term (related to tectonics and geodynamics) and short‐term (glacial cycle) processes. It is concluded that approximately 50% of the subsidence rates are related to tectonics, geodynamics and sediment load/compaction while the other half is controlled by ice melting. The effects of the glacial cycle through time are discussed. It is shown that the southeastern Po Plain generally behaves as a far‐field area in relation to the high‐latitude ice caps. Deviations from this behavior observed in the northeastern part of the Po Plain are tentatively interpreted as the effects of ice formation and melting in the Alps during the last glacial cycle.

Palaeogeographic and palaeoclimatic evolution of the Po Plain from 150-ky core records

Integrated sedimentological and micropalaeontological (foraminifers, ostracods, pollen) analyses of eight continuously cored boreholes, up to 140 m deep, reveal the depositional history and the palaeoclimatic evolution of southeastern Po Plain (northern Italy) over the last 150 ky. Age assignments are supported by the chronostratigraphic sequence framework calibrated by radiocarbon and pollen data, allowing detailed correlation with the oxygen-isotope record. Facies analysis (including identification of 12 distinct microfossils associations) and detailed stratigraphic correlations across several tens of km document a cyclic sedimentation pattern (including continental, coastal and shallow-marine deposits), which defines two transgressive–regressive sequences, deposited over the last two interglacial–glacial cycles. Two prominent stratigraphic markers, corresponding to wedge-shaped coastal sand bodies, are recorded between 0–30 and 100–125 m core depths. These sedimentary bodies were deposited during the two major transgressive pulsations and subsequent sea-level highstands of the last 150 ky, assigned to the Holocene and the Tyrrhenian (oxygen-isotope Substage 5e), respectively. The stratigraphic architecture of post-Substage 5e deposits shows consistent patterns of coastal evolution with changing sea-level position. Lowering of sea level between 125 and 70 ky (onset of Substages 5d and 5b, and Stage 4) resulted in extensive and repeated basinward shifts of facies, which can be observed across closely spaced unconformity surfaces associated to alluvial plain sedimentation (falling-stage systems tract). The general phase of sea-level fall was punctuated by short transgressive phases (Substages 5c, 5a and Stage 3 interstadials), which led to widespread deposition of organic-rich (lagoonal and swamp) deposits. Upper Stage 3 and Stage 2 deposits (lowstand systems tract) are replaced across a significant part of the study area by a hiatal surface. Holocene interglacial deposits are characterized by a retrogradational stacking pattern of coastal plain and littoral facies (transgressive systems tract), reflecting invariably the landward migration of a barrier–lagoon–estuary system. Subsequent highstand deposition (highstand systems tract) was characterized by extensive progradation of wave-influenced deltas and strandplains. The two major transgressive surfaces, of Tyrrhenian and Holocene age, are considerably easier to identify than the other key surfaces for sequence stratigraphic interpretation. The lowermost transgressive deposits display a pollen signature diagnostic of warm climate (interglacial) periods, showing wide forest development and relatively high pollen concentrations. By contrast, the deposits overlying the unconformable surfaces related to successive phases of sea-level fall are fingerprinted by pollen spectra dominated by Pinus and non-arboreal pollen types, with very low pollen concentrations, reflecting the onset of a stable cold climate vegetation characteristic of stadial to fully glacial conditions. The good match between facies architecture, pollen distribution and global sea-level evolution strongly suggests that Late Quaternary sedimentation in the Po Basin developed under a predominantly glacio-eustatic control. Stratigraphic architecture of the Po Basin thus can provide a useful analog for interpretation and correlation in the stratigraphic record of very rapid glacio-eustatic (fourth-order) cycles, with frequencies of about 100 ky.

Facies Architecture and Latest Pleistocene–Holocene Depositional History of the Po Delta (Comacchio Area), Italy

Integrated sedimentological and micropaleontological study of 16 cores and 137 piezocone penetration tests, approximately 40 m deep, in the Comacchio area enables the documentation of the depositional history of southeastern Po Plain in the last 30 ka, in response to fluctuating sea level. Sedimentation within an alluvial plain was the dominant feature across the entire study area during the pronounced sea level fall that culminated in the Last Glacial Maximum. Thin lowstand fluvial sediments form the lower part of a shallow incised valley above the Last Glacial Maximum unconformity, whereas a characteristic paleosol separates the last glacial alluvial plain deposits from the overlying postglacial deposits in the interfluves. Transgressive and highstand deposits show a well‐developed stacking pattern of retrogradational (coastal plain and estuarine) and progradational (deltaic) facies. Detailed reconstruction of transgressive paleogeography shows evolutionary features that can be useful for refined interpretation of coeval and ancient analogs. At relatively early stages of transgression (10.5–9 ka B.P.), sedimentation in a coastal plain was restricted to the incised valley, whereas nondeposition and pedogenesis took place on the interfluves. With rising sea level (9–6 ka B.P.), a wave‐dominated, barred estuary developed in the former topographic low. At peak transgression, after filling up of the estuarine systems with coastal, back‐barrier sediments, wide areas outside the valleys were flooded, aggradation extended onto the interfluve unconformity, and a shallow marine depositional environment developed across most of the study area. The depositional history during the subsequent highstand phase was dominated by progradation of the early Po Delta and reflects the complex interplay between high‐frequency sea level fluctuations, climate, subsidence, and autocyclic processes.

Geochemical and mineralogical variations as indicators of provenance changes in Late Quaternary deposits of SE Po Plain

Combined geochemical and mineralogical characterisation of mudstone-prone successions can provide suitable indicators of sediment provenance. A case study from the Late Quaternary depositional sequence of southeastern Po Plain shows that major changes in geochemical and mineralogical composition can be ascribed to changes in sediment dispersal patterns occurring during the last 30 ka in response to fluctuating sea level. The Po River, with a mixed contribution from the Alpine and Apenninic chains and its southern tributaries flowing from the Apennines, acted as the major feeders for the study area during the Late Quaternary. Chromium (and nickel) among trace elements, and serpentine (and dolomite) among minerals appear as the major provenance indicators for the study succession, allowing distinction of an Apenninic (chromium- and serpentine-poor) province from a mixed Alpine–Apenninic, Po-related (chromium- and serpentine-rich) province. The relatively low Cr/Al2O3 and serpentine/silicate ratios recorded in sediments of late Pleistocene age (<30 ka BP), which accumulated at the last glacial maximum, suggest that during lowstand times and early stages of transgression, the southeastern Po Plain was beyond the Po River influence, being fed uniquely by rivers of Apenninic provenance. Increasing Cr/Al2O3 and serpentine/silicate ratios, recorded within back-barrier transgressive deposits (8–10 ka BP) in the Comacchio and Ravenna sectors, reflect a major change in sediment supply taking place during the Holocene, when partially barred environments largely connected with the open sea became established in the study area, and Po-derived detritus was delivered to estuaries and lagoons by littoral drift. Maximum chromium and serpentine values are recorded at peak transgression and during the following sea-level highstand (6 ka BP–Present) when sediment supply exceeded the rate at which new accommodation space was created, leading to extensive Po-delta progradation. The drop in Cr/Al2O3 and serpentine/silicate ratios recorded in some cores at top of the Holocene succession reflects the local reestablishment, behind the prograding Po-delta complexes, of an alluvial plain drained by rivers of Apenninic provenance as a result of distributary channel switching and delta lobe abandonment. Geochemical and mineralogical analyses show negligible compositional variations between Pleistocene and Holocene deposits landward of the line of maximum marine incursion especially close to the basin margin. In these instances, sample composition throughout the entire stratigraphic succession clearly suggests an ongoing supply from the adjacent Apenninic chain. Comparison with sand compositional analyses from major sand bodies of the same stratigraphic succession highlights the complementary but fundamental role of geochemical and mineralogical characterisation of clays for provenance research.

High-resolution sequence stratigraphy from piezocone tests: an example from the Late Quaternary deposits of the southeastern Po Plain

Cone penetration tests are traditionally regarded as a major tool for geotechnical investigations. This study, based upon interpretation of 234 cone penetration tests with pore-pressure measurements (piezocone tests or CPTU), carried out in the Late Quaternary deposits of the southeastern Po Plain, shows how CPTU tests can also be used for sedimentological purposes, including detailed facies characterization, subsurface stratigraphic correlations, and identification of the key surfaces for sequence-stratigraphic interpretation. The Late Quaternary depositional history of the southeastern Po Plain, reconstructed on the basis of data from seventeen continuously cored boreholes, includes (1) alluvial plain development during the Late Quaternary lowstand and the early stages of transgression, (2) formation of a rapidly migrating barrier–lagoon system during the late transgressive phases (8800–6000 y BP), (3) construction and progradation of a wave-dominated delta (ancient Po delta) during the following sea-level highstand (6000–800 y BP), and (4) development of the present-day alluvial plain, following the delta lobe abandonment in the 13th century A.D. Local execution of CPTU tests in coincidence with drilling sites enables the calibration of borehole data with piezocone penetration profiles. Lithofacies characterization is based upon estimation of three major parameters: corrected cone resistance (qt), sleeve friction (fs), and pore water pressure (u). Plotting of qt versus the ratio of cone friction to cone bearing (FR) is adopted as the major tool for sediment texture classification. Eight major facies associations for the southeastern Po Plain are identified. These are, for decreasing qt values: (1) fluvial channel sands, (2) beach-ridge sands, (3) transgressive barrier sands, (4) crevasse sands and silts, (5) levee silts and sands, (6) floodplain silts and clays, (7) prodelta clays, and (8) marsh clays and peats. CPTU profile interpretation also provides the basis for the identification of the three major key surfaces within the Late Quaternary 4th-order depositional sequence. (1) The transgressive surface (TS), marking the boundary between the locally pedogenized, stiff Pleistocene alluvial clays and the overlying Holocene transgressive paralic deposits, has a distinctive pore-pressure response, with very low u values, and is characterized by a sharp downward increase in fs, which is paralleled by a moderate increase in qt. (2) The ravinement surface (RS), corresponding to the boundary between fine-grained back-barrier deposits and the overlying transgressive barrier sands, is invariably marked by a sharp upward increase in qt (and decrease in FR). (3) The maximum flooding surface (MFS), which is not clearly recognizable on the sole basis of core data, is identified within shallow-marine (prodelta) clays in combination with minor peaks of qt, which have been interpreted to reflect a laterally extensive fossil lag, with transition in proximal areas to sand (shell-rich?) layers. Simplicity, speed, and comparatively low costs of CPTU tests imply that an extensive use of this method, when used in conjunction with core programs, can be a very attractive alternative to economically less convenient methods for the geological mapping of alluvial/coastal plain areas consisting of non-gravel deposits.

Glacio-eustatic Control of Continental–Shallow Marine Cyclicity from Late Quaternary Deposits of the Southeastern Po Plain, Northern Italy

Integrated sedimentological and micropaleontological (foraminifera, ostracods, pollens) investigations of a 173-m-long continuous core in the subsurface of the SE Po Plain reveal a cyclic facies distribution of continental to shallow-marine deposits. Radiometric and pollen data enable an age attribution of the study units to the late Middle Pleistocene–Holocene. Glacioeustasy appears to have exerted a major control on facies development, as documented by the close relationships between cyclic lithofacies patterns and the curves of eustatic fluctuation. Particularly, relative sea-level falls and lowstand phases were characterized by the development of alluvial sedimentation, whereas major transgressive pulses and subsequent highstands are reflected by abrupt shifts to paralic and shallow-marine deposits. This facies architecture is paralleled by a distinctive pollen distribution, reflecting the alternation of a glacial type of vegetation, dominated by Pinus and nonarboreal pollen types, with interglacial mixed deciduous broad-leaved forests.