GPR reveals detailed masonry depths and advances building archaeology research, GPR maps hidden structures non-invasively to guide pre-plaster investigations, GPR provides data on internal wall dimensions and structural layouts

Highlights: Study of the magnetic properties of a glassmaker's workshop, measurements taken both on the structures and the activity area, initial measurements reveal notable differences between various parts of the furnace.

As a result of a long history in both archaeology and geophysics, France exhibits a wide panel of practices in archaeo-geophysics, going from archaeologists using geophysics as a supplementary tool for understanding their sites to applied geophysicists using archaeological sites as better constrained features and potential ground feedback. This chapter tries to scan this variety in the practices which overlap with a variety of contexts. After a brief overview of the backgrounds which control the practices in France, we show several examples that illustrate this diversity. Firstly, we will show a set of surveys of rural areas coming from both public and private institutions. Secondly, we will present how archaeological sites in urban areas are assessed with the geophysical techniques. Thirdly, we will address what can be done in what we define as the “specific” context. In each context, we will highlight how geophysical techniques could improve itselves with the help of archaeological sites took as the place for an intensive interdisciplinary research. We conclude that archaeology can be a way to make geosciences progress by bringing together geology, soil science, geotechnics, geochemistry, and geophysics.

The double tombolo of Orbetello, in Italy, has formed during the Holocene around an ancient central tombolo. Earlier models consider that its sand barriers formed as sand spits that stretched from the mainland to a coastal island before enlarging seawards. This evolution, however, remains speculative. In order to test these models, we conducted the first study of a double tombolo that combines coring of its sand barriers and comprehensive imaging of its internal structure using sub-bottom acoustic surveys offshore and in the back-barrier. Sediment ages were constrained by 14C, luminescence, and U/Th dating. Acoustic images below the lagoon show that the barriers are in fact broad regressive strandplains that initiated on the flanks of the preexisting central isthmus when sea level was -7 +/- 1 m lower than today. The strandplains then rose upwards and outwards, tracking sea level rise over the past 7 kyr. The oldest and lowest parts of the strandplains were flooded into the shallow intervening lagoon. The central isthmus is composed of regressive sand barriers accreted around a MIS 5.5 core during subsequent stages MIS 5.3 and MIS 5.1. The emplacement of the isthmus interrupted longshore drift between the mainland and the coastal island, converting the flanks of the initial tombolo into terminal sinks in which sand accretion accelerated, spurring early and rapid regression during the Holocene. A review of the environmental parameters conducive to double tombolo formation suggests that double tombolos may represent a frequent, albeit short-lived stage during the enlargement of single tombolos.

This chapter groups together information about the location and geographical context of the site, the history of its discovery and first test excavation in 2009, the excavation strategy, methods and techniques implemented from 2011 to 2016, the general organisation of the site and the nomenclature used for describing the different excavated areas. More specifically, this chapter reports on the different events that influenced and sometimes drastically changed the course of the excavation. This was especially true in 2013, when the plot owner prohibited access to the Central Sector, precluding completion of the excavation of the Communal building and its immediate surroundings. This forced the research to expand to the peripheral areas, namely Sectors B and F, where several unsuspected residential buildings were found and studied. For all these round buildings, the general excavation strategy consisted in mechanical surface stripping, followed by a careful stratigraphic excavation of their fills conducted in quadrant trenches separated from each other by berms, in order to preserve and study profiles. All the non-reworked sediments were water sieved, and additional flotation and fine-mesh sieving were implemented for subsamples from the most interesting structures or stratigraphic units.

We identify the previous phases of a building by means of GPR of a Roman quarter. We analyze the data from excavations and geophysics in a complementary way to understand the evolution of an urban space.

Albert Hesse was one of the pioneers in archaeometry in France. He has developed the electrical methods, and more specifically the continuous electrical surveying methods and focused very early on urban archaeology and geophysics. This paper focusses on his work, showing specific interactive maps to highlight the position of his different surveys world-wide.

<p>At the end of the Bronze Age, technical improvements have made possible the rise of the first generation of major sea powers around the Mediterranean realm, such as Etruria in Italy. The Etruscan coast was fringed by large lagoons, of which only one survives today: the lagoon of Orbetello. This peculiar lagoon is held between two sand spits that connect the former island of Argentario to the mainland. A third sand spit lies in the middle of the lagoon, and supports the Etruscan city of Orbetello. Archeological investigations suggest that the lagoon was connected to the sea through a natural outlet until the 9<sup>th</sup> century BCE, when an integrated management plan of the lagoon was implemented to optimize fishing. Subsequent closure of the natural outlet implies that lagoon management heavily subsequently relied on man-made openings to maintain the lagoon connected to the sea and nearby rivers. Today, three canals connect the lagoon to the sea. Management plans were implemented in the late 20<sup>th</sup> Century to fight a massive phase of eutrophication driven by excess release of fertilizers. Eutrophication as responsible for extensive fish kills, and to the release of mercury in the water column. Little is known about lagoon management and the evolution of the city before the 17<sup>th</sup> century CE, but it is clear that the wealth of the city of Orbetello and the health of its lagoon have been strongly correlated over the past three millennia.</p><p>               To track this coevolution, we conducted a coring campaign coupled to sub-bottom imaging in the very shallow (<1.5m) waters of this extensive (30 km<sup>2</sup>) lagoon. iXblue Echoes 10 000 sub-bottom profiler reveals individual layers that can be traced across the lagoon, allowing stratigraphic correlations between cores, and highlighting the environmental significance of the sedimentary facies. Architecture of the deposits reveals a pronounced transgression of the lagoon over its shallowly inward-dipping margins since Antiquity. This led to the flooding of an array of regularly-spaced Roman farms along its southern shorelines, and to a more important flooding of Etruscan structures. Lagoon level rise was driven by a combination of regional sea level rise and fluctuations in the hydraulic balance of the lagoon, controlled by the opening and closure of canals. Sub-bottom imaging reveals buried structures tentatively interpreted as docks and canals used for navigation and salinity control.</p><p>               Sediment analyses under XRF scanning, Rock Eval, and hyperspectral imaging reveals that sedimentation is marked by an alternation of black, shelly organic silty clays and decimeter-thick layers of broken shells. Radiocarbon dating indicates that the cores capture up to five millennia of sedimentation. Ongoing analysis of mercury and phosphorus content, ostracods and pollen assemblages, and chromatic pigments in the organic fractions are expected to document the links between sediment facies, eutrophication and salinity crises, and the rise and demise of land and lagoon management through the past three millennia.</p><p>               A sub-bottom profiling campaign in June 2022 is aimed at mapping the observed structure. Further coring is planned near putative man-made structures next Fall.</p>

Albert Hesse (1938-2022), directeur de recherche au CNRS, était un spécialiste de prospection géophysique, discipline dont il a été un des initiateurs en France et acteur tout au long de sa carrière. Il a été l’un des membres fondateurs de l’association GMPCA en 1976 et cette note est destinée à rendre hommage à sa carrière et ses engagements pour sa discipline et plus largement pour l’archéométrie.

– Use of high resolution GPR mapping for the study of masonry walls. – Delineation of underlying the main characteristics of the wall. – Evaluate the different steps of renovation and/or partial reconstruction of the wall.

Établissements porteurs de l'opération : EFA Données scientifiques produites : Mission de terrain de l'EFA-Fouilles et prospections à Malia 5e.Malia -Recherches dans le secteur Pi (2005-2016) 5g.Malia -Recherches sur le paléoenvironnement (2015-2017) Carottages dans le marais Malia 2019Ce rapport résume les activités de terrain qui ont concouru à enrichir nos connaissances sur la ville minoenne de Malia en mettant en oeuvre différentes méthodes d'acquisition de données.Elles ont permis de préciser l'extension et la densité d'occupation de la ville, l'articulation entre le marais côtier et la région de la Plage du Moulin, la nature de l'occupation du sol dans la région liminale de Chrysolakkos, entre les secteurs habités et les nécropoles, mais aussi de compléter le plan de l'îlot urbain du secteur Pi et de réviser la chronologie de l'ensemble architectural de Chrysolakkos.Le rapport reprend l'ordre de la demande d'autorisation, et non celui dans lequel les opérations se sont succédé sur le terrain.

Summary Electrostatic profiling and mapping have been carried out in an urban context with two different geometries allowing the prospection of the first 3–4 meters. Despite the larger size of the prospection devices, compared to ground-penetrating radar (GPR), it has been successfully applied at almost all GPR locations in parallel within the same few days' survey. At an intermediate operating frequency of 15 kHz, the method provides information on both electrical resistivity and "low frequency" effective dielectric permittivity (mainly linked to polarization in clayey materials), and is therefore complementary to the GPR method primarily used in urban prospection.

– Electrical resistivity and dielectric permittivity mapping using an electrostatic survey device. – GPR delineation of probable ancient anchor point of the ancient bridge. – Combination of GPR and electrostatic surveys for urban archaeology.