Undisturbed iron industry sites in the Sonian Forest, Belgium

In the Sonian Forest of Middle Belgium, undisturbed remnants of ancient metallurgic activity, dating from the Early Middle Ages, are found. They occur in an area with iron-rich geological formations at shallow depth below a loess cover. Iron-industry traces include scoria mounds, which always occur in pairs. Associated with each pair is a single large zone with a reddish-pink colour of the upper part of the soil. These zones were formed by heating of the soil from the surface, most likely during roasting of the iron sandstone ore as pretreatment. The surface horizon was later homogenised by biological activity, down to the top of the Bt horizon or the compacted part of the E horizon. Charcoal mounds, whose distribution is not clearly related to that of other archaeological structures, date at least partly from more recent periods. Another associated feature is an area with a surface cover of yellowish sands, representing a site where the sandstone was unloaded or cleaned before further treatment. The preservation of these various features related to ancient metallurgic activity is due to the unique land-use history of the Sonian Forest, where a centuries-long continuous prohibition of agricultural practices has prevented the destruction of shallow surface structures

Sedimentary and diagenetic features in saline lake deposits of the Monegros region, northern Spain

26 Pag., 3 Fig. The definitive version is available at: http://www.sciencedirect.com/science/journal/03418162The Monegros region in northern Spain is marked by the occurrence of a large number of ephemeral to dry lake basins, occupying small karstic depressions. The lacustrine sediment fill of these basins contain various carbonate and silicate minerals whose origin and palaeoenvironmental significance is poorly understood. For the present study, 14 lake basins were sampled in order to establish vertical, lateral and regional variations in mineralogical and textural characteristics, aimed at determining themode of formation of the various mineral phases present. In nearly all basins, the same sequence of three lithological units is recognized, including a basal clayey unit, a middle magnesite-bearing and gypsum-rich unit, and a calcite- and dolomite-dominated surface unit. Distribution patterns of carbonate minerals indicate that magnesite is a synsedimentary precipitate, dolomite formed as a diagenetic authigenic phase, and calcite is partly authigenic and partly allogenic. All clay minerals, including sepiolite and smectite, appear to be allogenic. Regional variations are marked by similarities between groups of neighbouring basins, but no overall trend related to regional drainage patterns is recognized. The middle lithological unit records a lake stage with predominantly chemical sedimentation (Unit II), overlying a less well documented interval corresponding to a perennial lake stage with lower salinity (Unit III), whereas the surface unit formed during a period with predominantly clastic sedimentation. Based on a comparison with other regional records, the middle unit is attributed to an Early Holocene humid stage, separated from the overlying Late Holocene deposits by a hiatus that corresponds to a Mid Holocene arid stage.This study was funded by project G.0103.05N of the Fund for Scientific Research (Flanders), and by projects AGL2006-01283/AGR and AGL2009-08931/AGR of the Spanish Government.Peer reviewe