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Integration of different kinds of data is an important issue in archaeological prospection. However, the current methodological approaches are underdeveloped and rarely use the data to their maximum potential. Common approaches to integration in the geophysical sciences are mostly just various forms of comparison. We argue that true integration should involve the mathematical manipulation of input data such that the original values of the input data are changed, or that new variables are produced. To address this important research gap, we present an innovative approach to the analysis of geochemical and geophysical datasets in prospection-focused disciplines. Our approach, which we refer to as "multiscalar integration" to differentiate it from simpler methods, involves the application of mathematical methods and tools to process the data in a unified way. To demonstrate our approach, we focus on integrating geophysical data (magnetometry) with geochemical data (elemental content). Our approach comprises three main stages: Quantification of the data deviation from random distributions, linear modelling of geophysical and geochemical data and integration based on weighting of the different elements derived in previous steps. All the steps of the workflow can be also applied separately and independently as needed or preferred. Our approach is implemented in the R environment for statistical computing. All data, functions and scripts used in the work are available from open access repositories (Zenodo.org and Github.com) so that others can test, modify and apply our proposed methods to new cases and problems. Our approach has the following advantages: (1) It allows the rapid exploration of multiple data sources in an unified way; (2) it can increase the utility of geochemical data across diverse prospection disciplines; (3) it facilitates the identification of links between geochemical and geophysical data (or generally, between point-based and raster data); (4) it innovatively integrates various datasets by weighting the information provided by each; (5) it is simple to apply following a step-by-step framework; (6) the code and workflow is fully open to allow for customization, improvements and additions. [ABSTRACT FROM AUTHOR]

The La Bassée floodplain area is a large groundwater reservoir controlling most of the water exchanged between local aquifers and hydrographic networks within the Seine River basin (France). Preferential flows depend essentially on the heterogeneity of alluvial plain infilling, whose characteristics are strongly influenced by the presence of mud plugs (paleomeander clayey infilling). These mud plugs strongly contrast with the coarse sand material that composes most of the alluvial plain, and can create permeability barriers to groundwater flows. A detailed knowledge of the global and internal geometry of such paleomeanders can thus lead to a comprehensive understanding of the long-term hydrogeological processes of the alluvial plain. A geophysical survey based on the use of electromagnetic induction was performed on a wide paleomeander, situated close to the city of Nogentsur-Seine in France. In the present study we assess the advantages of combining several spatial offsets, together with both vertical and horizontal dipole orientations (six apparent conductivities), thereby mapping not only the spatial distribution of the paleomeander derived from lidar data but also its vertical extent and internal variability. [ABSTRACT FROM AUTHOR]

The La Bassée floodplain area is a large groundwater reservoir controlling most of the water exchanged between local aquifers and hydrographic networks within the Seine River basin (France). Preferential flows depend essentially on the heterogeneity of alluvial plain infilling, whose characteristics are strongly influenced by the presence of mud plugs (paleomeander clayey infilling). These mud plugs strongly contrast with the coarse sand material that composes most of the alluvial plain, and can create permeability barriers to groundwater flows. A detailed knowledge of the global and internal geometry of such paleomeanders can thus lead to a comprehensive understanding of the long-term hydrogeological processes of the alluvial plain. A geophysical survey based on the use of electromagnetic induction was performed on a wide paleomeander, situated close to the city of Nogentsur- Seine in France. In the present study we assess the advantages of combining several spatial offsets, together with both vertical and horizontal dipole orientations (six apparent conductivities), thereby mapping not only the spatial distribution of the paleomeander derived from lidar data but also its vertical extent and internal variability. [ABSTRACT FROM AUTHOR]

The La Bassée floodplain area is a large groundwater reservoir controlling most of the water exchanged between local aquifers and hydrographic networks within the Seine River Basin (France). Preferential flows depend essentially on sediment fills, whose characteristics are strongly influenced by paleomeander heterogeneities. A detailed knowledge of the internal heterogeneities of such paleomeanders can thus lead to a comprehensive understanding of its long-term hydrogeological processes. A geophysical survey based on the use of electromagnetic induction was performed on a representative paleomeander, situated close to the city of Nogent-sur-Seine in France. In the present study we assess the advantages of combining several spatial offsets, together with both vertical and horizontal dipole orientations (6 apparent conductivities), thereby mapping not only the spatial distribution of the paleomeander derived from LIDAR data, but also its vertical extent and internal variability. [ABSTRACT FROM AUTHOR]

This article addresses the characterization of resistive archaeological targets and near surface structures by electromagnetic induction (EMI). It presents tests achieved with the DualEM-421S instrument (Dualem Inc., Milton, Canada) in order to be able to quantitatively compare these measurements to the standard technique of direct-current (d.c.) resistivity. The test was done over the Gallo-roman site of Vieil-Evreux in Normandy, France and one-dimensional (1D) and three-dimensional (3D) inversions were applied to the data set obtained. We have first investigated the signal-to-noise ratio of each of the six DualEM receiver coils both in a static mode and for a quad-pulled system. The dependence on the roll angle was also measured and it is shown that rotation of DualEM must be taken into account if the roll angle is more than ±10°. Absolute calibration and in-phase/quadrature (out of phase) component discrimination was checked by measuring the response of a small conductive and non-magnetic sphere. Several electromagnetic soundings by measuring the instrument response at different heights were done in order to check the quadrature (out-of-phase) response of the instrument. Inversions of these electromagnetic soundings were compared to d.c. vertical electric soundings (VESs) over four locations and found in accordance. Several maps using different coil configurations (HCP, VCP, PERP) and different heights were performed and inverted, both for a wide mesh (5 m) and for a finer one (0.5 m). The wide mesh allows a global and rapid description of the surface geology context (continuous d.c. measurements cannot deliver equivalent depth of investigation). The fine mesh conductivity maps clearly show the walls of a fanum (temple) as well as other structures and prove that the DualEM-421S is able to map correctly archaeological resistive targets. These maps and their interpretations were compared to previous results obtained by d.c. technique. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT Statute laws concerning preventative archaeology adopted in France in 2001 for threatened sites required development of evaluation techniques. The common methodology used during the past 10 years has been extensive excavation. This method delivers a direct record of the discovered archaeological features and of their distribution. However, the success of visual observation can be variable, depending on geological context and the feasibility of envisaging the entire archaeological settlement from the part that is observed. We report here a case study from an early Middle Age settlement located on a floodplain. It was partially excavated and the alluvial context makes the features difficult to recognize for archaeologists. We show how the geophysical survey complemented the archaeological survey and allowed the detection of previously unrecognized features. In a second step, we compare the results of surveys with magnetic and electromagnetic methods on a topsoil stripped area and the neighbouring surface. From this analysis we conclude that a significant part of the unrecognized features discovered were present above the level of stripping. This example underlines that the practice of topsoil stripping has to be reconsidered, and should be integrated with geophysical survey to limit the potential loss of archaeological information. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]