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Quaternaire Electronic reference
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    Quaternaire Revue de l'Association française pour l'étude duQuaternaire   vol. 25/3 | 2014 Volume 25 Numéro 3 Human environmental impact from the neolithicto the middle ages: a pluridisciplinary approachfocused on a small catchment area at thekochersberg (Bas-rhin, France) Impact anthropique du néolithique au moyen-âge : approche pluridisciplinairedans un bassin versant élémentaire du Kochersberg (Bas-Rhin, France) Damien Ertlen, Nathalie Schneider, Emilie Gauthier, Julian Wiethold,Hervé Richard, Yohann Thomas and Eric Böes Electronic version URL: http://journals.openedition.org/quaternaire/7047DOI: 10.4000/quaternaire.7047ISSN: 1965-0795 Publisher Association française pour l’étude du quaternaire Printed version Date of publication: 1 September 2014Number of pages: 195-208ISSN: 1142-2904  Electronic reference Damien Ertlen, Nathalie Schneider, Emilie Gauthier, Julian Wiethold, Hervé Richard, Yohann Thomasand Eric Böes, « Human environmental impact from the neolithic to the middle ages: a pluridisciplinaryapproach focused on a small catchment area at the kochersberg (Bas-rhin, France) », Quaternaire [Online], vol. 25/3 | 2014, Online since 01 March 2016, connection on 01 May 2019. URL : http:// journals.openedition.org/quaternaire/7047 ; DOI : 10.4000/quaternaire.7047 © Tous droits réservés  Quaternaire , 25 , (3), 2014 , p. 195-208  Manuscrit reçu le 20/06/2013, accepté le 16/06/2014 HUMAN ENVIRONMENTAL IMPACT FROM THE NEOLITHIC TO THE MIDDLE AGES: A PLURIDISCIPLINARY APPROACH FOCUSED ON A SMALL CATCHMENT AREAAT THE KOCHERSBERG (BAS-RHIN, FRANCE) n Damien ERTLEN 1,2 , Nathalie SCHNEIDER  2,1 , Emilie GAUTHIER  3 , Julian WIETHOLD 4,5 , Hervé RICHARD 3 , Yohann THOMAS 2  & Eric BÖES 2 ABSTRACT The Kochersberg loess area, west of Strasbourg (France), has been explored with the aim to reconstruct the Holocene land-scape dynamics. Sediments, pollen and plant macro-remains were analysed from an organic rich sediment core, sampled in the thalweg of a small catchment. The several proxies are offering a multiscalar view of landscape evolution from the Neolithic to the Middle Age. At the catchment scale, major changes in the landscape are always associated with intense phases of occupation revealed by archaeological excavations. Keywords : Holocene, colluviums, loess, palynology, macrofossil plant remains, anthropisation, Upper Rhine valley RÉSUMÉ IMPACT ANTHROPIQUE DU NÉOLITHIQUE AU MOYEN ÂGE : APPROCHE PLURIDISCIPLINAIRE DANS UN BASSIN VERSANT ÉLÉMENTAIRE DU KOCHERSBERG (BAS-RHIN, FRANCE)Le secteur loessique du Kochersberg, à l’ouest de Strasbourg, a été exploré dans le but de reconstruire les dynamiques du  paysage au cours de l’Holocène. Les sédiments, le pollen et les macrorestes végétaux ont été extraits d’une carotte riche en matière organique prélevée dans le thalweg d’un bassin versant élémentaire. Les différentes archives offrent une vision multi-scalaire de l’évolution du paysage depuis le Néolithique jusqu’au Moyen Âge. A l’échelle du bassin versant, les changements importants du  paysage sont toujours associés à des phases de forte implantation révélées par les fouilles archéologiques. Mots-clés  : Holocène, colluvions, loess, palynologie, macrorestes, anthropisation, fossé rhénan  berg area, covered by thick loess deposits. The Pleisto-cene loess stratigraphy has been extensively studied on the reference site of Achenheim, Bas-Rhin (Wernert, 1938; Heim et al  ., 1982). However, the morphogenesis of the Holocene and its resulting stratigraphy was never explored. Palynological data are numerous in the Vosges Mountains (Dubois & Hatt, 1930; Kalis et al  ., 2006), scarce in the upper Rhine Graben (Thévenin & Heim, 1983; Lechner, 2005) and no data exists in the Kochers- berg region. Plant macrofossil remains and charcoal, deriving from archaeological features of different exca-vation sites on the railway track were investigated during  post-excavation studies (Durand et al  ., 2011; Nocus et 1  Image, Ville, Environnement, UMR 7356 - Université de Strasbourg / CNRS, 3 rue de l’Argonne, FR-67083 STRASBOURG.  Email  : damien.ertlen@live-cnrs.unistra.fr  2  Inrap Grand Est sud, Centre archéologique de Strasbourg, 10 rue d’Altkirch, FR-67100 STRASBOURG.   Emails : nathalie.schneider-schwien@inrap.fr, yohann.thomas@inrap.fr, eric.boes@inrap.fr  3  Chrono-environnement UMR 6249, CNRS / Université de Franche-Comté, 16, route de Gray, FR-25030 BESANÇON.  Emails : emilie.gauthier@univ-fcomte.fr, herve.richard@univ-fcomte.fr  4  Inrap Grand Est nord, Centre archéologique de Metz, Laboratoire archéobotanique, 12 rue Méric FR-57063 METZ.  Email  : julian.wiethold@inrap.fr  5  ArTeHiS UMR 6298, Université de Bourgogne / CNRS, 6 boulevard Gabriel, FR-21000 DIJON. 1 - INTRODUCTION The construction of a new TGV railway track between Baudrecourt (Moselle) and Vendenheim (Bas-Rhin) in the frame of the LGV Est network is going on since 2010 (fig. 1). Prior to this infrastructure project, which has destructive consequences on the sedimentary and cultural relics, extensive archaeological excavations were carried out on the future railway track by using mechanical means (fig. 1). In addition to the traditional archaeological survey, geoarchaeological and palaeoen-vironmental surveys were carried out. Here we focused on the eastern part of the railway track, the Kochers-  196 al. , 2011; Wiethold, 2012), but palaeoecological analysis  based on natural sediments and peat were still lacking. Therefore, in addition to systematic excavations, four sediment cores were sampled from four different catch-ments. The most interesting sediment record was found in the small valley Ungerbruchgraben  (Mittelhausen, Bas-Rhin; fig. 2 and 3), where a 2 m core was sampled. Pollen and other microfossils, waterlogged plant remains, and sediment analysis were compared to the rich archaeo-logical heritage in and around the catchment. Sites of the Michelsberg culture (Middle Neolithic, ca. 4,200-3,500 BC), the Hallstatt and La Tene period (Iron Age) and from the Middle Ages were very clearly identified in the area. Evidence of a Bronze Age occupation is almost non-existent and signs of the Roman occupation are rela-tively scarce. Over 6,000 years of human impact at local scale were recorded. 2 - MATERIAL AND METHODS 2.1 - THE UNGERBRUCHGRABEN CATCHMENTThe  Ungerbruchgraben  is a small catchment situated in the eastern part of the Kochersberg region (Bas-Rhin, France). The Kochersberg is a hilly region enclosed by two major faults situated between the Vosges Mountains (west) and the Upper Rhine valley (east). The creek flows from west to east. The catchment of the Ungerbruch- graben  depression is 1,000 m long and 700 m wide, the slopes are very smooth (> 5 %) except for the western  part of the catchment. The substrate, composed of sedi-mentary rocks from the Mesozoic, is entirely covered  by a thick Quaternary loess deposit. Except from some riparian forest relicts, the entire surface is presently culti-vated (ADEUS, 2011). Therefore, and despite smooth slops, soils are poorly developed because of recent inten-sive erosion (Auzet et al. , 1995; Armand, 2009). At the  place of the coring (48°41’59’’N, 07°37’49’’E), the water flow is permanent and the creek about one meter large. The floodplain is about 10 m large.2.2 - SEDIMENTOLOGYTwenty seven sedimentary layers were described (fig. 4). Particle-size distribution was measured for each unit by laser granulometry (Beckman-Coulter, LS230). Preliminary, the samples had been treated by H 2 O 2  to destroy organic matter. The samples had been also washed successively by KCl, distillated water and sodium hexa-metaphosphate to deflocculate the aggregates without destructing the carbonate. On one hand, this method (1)  provides a particle size distribution close to the srcinal sediment distribution before its transportation and (2) allows a good interpretation of involved geomorpho-logical processes. On the other hand, the interpretation of the mineral fraction distribution of organic rich sedi-ment is more difficult. Thus it should be kept in mind that for the very organic rich samples the distribution that appears often as sandy represents only a small part of the bulk sediment. Sampling for organic matter (OM) content measurement was done continuously with 1.8 cm wide plastic boxes (77 samples). OM was measured by loss on ignition at 375 C° during 16 h.2.3 - PALYNOLOGYSamples were systematically taken every 4 cm and even every 2 cm in the neighbouring of sedimentary limits. Sediment samples were processed for pollen and non-pollen palynomorph (NPP) analysis using standard techniques (Björck et al. , 1978; Moore et al. , 1991). They were treated with HCl (10 %), NaOH (10 %), HF (40 %), ZnCl 2  and acetolysis. The conservation of pollen and micro-fossils varies mostly between bad and accep-table. As a consequence, some samples, especially from Fig.   1: The railway line LGV Est (Ligne à Grande Vitesse Est) between Loraine and Alsace, France.  Fig.   1   : La Ligne à Grande Vitesse entre l’Alsace et la Lorraine (LGV Est), France.  197 Fig.   2: Overview of the Ungerbruchgraben  catchment (Alsace, France) (photo F.   Schneikert).  Fig.   2 : Vue d’ensemble du bassin versant élémentaire de l’ Ungerbruchgraben  (Alsace, France) (photo F.   Schneikert). Fig.   3: Archaeological remains in the Ungerbruchgraben catchment and its surroundings (Alsace, France). 1/ Pit from the Hallstatt period (Zehner & Zefner, 1993), 2/ Merovingian burials, 9.5/ Pits and burials from La Tène and late Bronze Age pit, 10.1/ Pit attributed to the Michelsberg culture, 10.2/ Pit probably from the Iron Age, 10.3/ Pit dated to the older Iron Age (Hallstatt period).  Fig.   3   : Restes archéologiques dans le bassin versant de l’ Ungerbruchgraben  et ses alentours. 1/ Fosse hallstattienne (Zehner & Zefner, 1993), 2/ Tombes   mérovingiennes, 9.5/ Fosses et sépultures de La Tène et fosse de l’Âge du Bronze   récent, 10.1/ Fosse attribuée à la culture Michelsberg, 10.2/ Fosse  probablement de l’Âge du Fer, 10.3/ Fosse datée de l’Âge du Fer ancien (période Hallstatt).  198 the bottom part of the core, cannot be considered being suitable for pollen analysis. Pollen grains were identified with the aid of a reference collection of modern pollen types and photographs (Reille, 1992; Beug, 2004).  Alnus , Cyperaceae, hygrophilous and aquatic taxa, spores and non-pollen palynomorphs were excluded from the pollen sum. The TILIA-programme was used to draw the pollen diagram (Grimm, 1991). The implemented programme CONISS allowed a stratigraphically-constrained cluster analysis to obtain a zonation of the Pollen diagram in local pollen assemblage zones (Grimm, 1987).2.4 - PLANT MACROFOSSIL ANALYSISSampling was done continuously with samples of 8 cm length and with a volume of about 200 ml per sample. A low vertical resolution was necessary in order to collect a sufficient amount of plant remains. The upper sample was only 6 cm thick. At important layers limits, sample limits were adapted (for example: 176-183 cm, 183-188 cm, 248-252 cm). Carbonates were eliminated with HCl (5 %). Samples with high organic content were heated and treated with 5 % potassium hydroxide in order to disaggregate the material and destroy the humic acids. Then, all the samples were watersieved using standard laboratory sieves with 0.315 mm and 1.0 mm mesh sizes. Plant remains were sorted and identified under a micros-cope (Olympus SZ40) with 7 to 10 X magnification or 40 X for precise observations. General principle for plant remains determinations are given by Jacomet & Kreuz (1999), Marinval (1999) and Birks (1980). For the deter-mination of waterlogged plant remains, the reference collection of modern and archaeological seeds of the archaeobotanical laboratory of Inrap in Metz (Lorraine, Fig.   4: Description of the sediments (core E86) in the Ungerbruchgraben  thalweg (Alsace, France).  Fig.   4   : Description des sédiments (carottage E86) dans le thalweg de l’ Ungerbruchgraben  (Alsace, France).
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