Geoarchaeology or the contribution of geosciences for studying past human societies

Julien Curie, Ségolène Vandevelde, Amélie Quiquerez and Christophe Petit 1 CNRS, UMR7041 ArScAn/MSH Mondes, 21, allée de l’Université, 92023 Nanterre Cedex, France 2 UMR6298 ARTEHIS, CNRS/uB, 6 Bd Gabriel, 21000 Dijon, France 3 Université Paris 1-Panthéon-Sorbonne, UMR7041 ArScAn, équipe Archéologies environnementales, Paris, France 4 MSH Mondes, 21, allée de l’Université, 92023 Nanterre Cedex, France 5 Université de Bourgogne, UMR6298 ARTEHIS, CNRS/uB, 6 Bd Gabriel, 21000 Dijon, France


Introduction to the Special Issue "Geosciences and Human-Environment interactions"
This special issue of the BSGF -Earth Sciences Bulletin dedicated to "Geosciences and Human-Environment interactions" gathers ten research papers that come out of the Geoarchaeology & Environment session of the 26th edition of "Réunion des Sciences de la Terre" (Earth Sciences Meeting, "Société Géologique de France"/French Geological Union, Lille, France, 22nd-26th October 2018). With more than thirty abstracts submitted on this topic and with its thirty accepted oral presentations, this session has highlighted the growing interest for Geoarchaeology.
In France, the last decades have seen the emergence and increase of trans-disciplinary collaborations between earth scientists and archaeologists, as well as the merge of these to disciplines into integrated geoarchaeological approach. Geoarchaeology uses multidisciplinary approaches developed in Earth Sciences to study the interrelations between human societies and their environment over the long term. Its main goal is to contribute to a better understanding of the spatial and temporal patterns of interactions and/or relationships between societies and environment.
Geoarchaeologyconsidered here as "Geosciences for studying Past Human Societies"covers a wide range of scopes and encompasses multiple thematic areas such as: locating and detecting archaeological sites in their environmental and geomorphological contexts, analysing local and regional stratigraphic and microstratigraphic records, studying anthropogenic vs "natural" sediments and landforms, reconstructing site formation processes and the underlying human impact on environment, producing paleoenvironmental and chronological interpretations, studying artefacts and ecofacts for elucidating resource origin, manufacturing practices and cultural networks, etc.
This special issue explores all these research topics in ten papers grouped into three sets. (1) The first set of papers presents intra-site analyses carried out on the sedimentary archives of settlement sites in Palaeolithic and Medieval contexts (respectively Vandevelde et al. and Borderie et al.); (2) the second set presents provenance studies that aim to track the origin of various types of materials (metal, stones, ceramic) from Neolithic, Antique and Pre-Columbian archaeological sites (respectively Tomczyk et al. 2 What analyses carried out on sedimentary archives of settlement sites can tell us about human activities? The paper from Vandevelde et al. presents a geoarchaeological study of finely laminated parietal carbonated crusts of the Grotte Mandrin Palaeolithic site (southern France). Using LIBS micro-spectroscopy, the authors propose to reconstruct palaeo-fire chronicles and to set them up on a micro-chronological timescale (with annual resolution), thus developing a new research area: the fuliginochronology. This method and the resolution they reach allow the authors to access new information like the precise timing of occupations on the site. The next paper focuses on much more recent and urbanised context. Observed in several urban archaeological stratifications, the "Dark Earth" formations are major common medieval pedo-sediments seen as archives of past human activities in inhabited areas. By taking them into account in several archaeological stratifications from Medieval urban sites all over Europe and by using a multidisciplinary approach (underlying the organic carbon, phosphorous and heavy metals contents of these sedimentary deposits), the paper from Borderie et al. improves our acknowledgment of early medieval urban societies, teaching about their way of lives, especially their waste management.
3 What can material analyses can tell us about provenance?
Through a case study on Neolithic copper mines, the paper from Tomczyk et al. presents multivariable statistical methods applied on lead isotopes coming from gitological data and geoarchaeological database in order to improve the tracing of copper artefacts' production sources.
In the second paper about provenance studies, Vals et al. present an exhaustive study of the origins of the stones used in the famous Sanctuary of Apollo in Delphi, Greece (known for its Oracle during Greek Antiquity). They provide an identification of the stone facies employed in the archaeological site as well as of their origin.
The petrographical analysis performed on ceramics from three pre-Columbian sites on the archipelago of Guadeloupe (French West Indies) by Fronteau and van den Bel demonstrates the presence of grog used as temper and convincingly conclude about the origin and the spreading of this true regional chrono-cultural marker.

How to reconstruct the evolution of environments?
The archaeobotanical study performed by Schaal and Naton on the sediments that accumulated in an oxbow-lake of the River "Meuse" (northeast of France) led to build a true and strong taphonomic reference frame that constrains taphonomic processes and criteria preservation of the ecofacts and improves our knowledge of the palaeoecology of the Preboreal period (11.7-10.7 ka BP).
The paper from Ollive et al. provides new features on the so-long debate about the closed depression (named "mardelles") observed on Keuper marls of the northeastern Paris Basin. Thanks to rescue archaeological excavations along the high-speed train line "LGV-Est Européenne" together with a multidisciplinary approach, the authors demonstrate the natural origin of these structures and precisely describe the geological processes involved, including the human-induced sedimentary filling.
The paper from Gouriveau et al. focuses on reconstructing palaeo-environments and human-environment interactions throughout the Holocene (since 6600 cal. BP to Middle-Age) in the northeast of France from a multidisciplinary palaeoenvironmental study performed in bog-pond located near the ruins of the medieval castle of Waldeck (Northern Vosges, France).
Following the recent expansion project of the Dunkerque's harbor (north of France), Deschodt et al. investigated the past estuary of a sub-basin of the coastal River "Aa" thanks to rescue archaeological operations. Through the use of trans-disciplinary methods (historical archives, lithostratigraphic analysis, electrical conductivity mapping), the authors propose a reconstitution of the landscape evolution and the human occupations in the area since the 10th century CE.
Blond et al. propose a reconstitution of environmental and landscape changes around the archaeological site of Wakarida (Ethiopia). From an approach combining field measurements, laboratory analyses, dating performed on colluvial and alluvial, they discuss how climate and anthropogenic processes have both contributed to reshape the landscapes through Early and Middle Holocene and during the Classical Aksumite (150-400/450 CE) and the post Aksumite (800/850 CE) periods.
This special issue brings together a truly diverse group of scholars showing their efforts in developing, testing, and debating methodologies in the domain of Geoarchaeology. The geoarchaeological approach must work on breaking down the barriers between disciplinary approaches and foster integrative approaches leading to the production, in many ways, of scientific features focusing on Societies-Environments interactions.
Ce numéro thématique explore tous ces sujets de recherche dans dix articles regroupés en trois ensembles.