Anza palaeoichnological site, Late Cretaceous, Morocco. Part III: Comparison between traditional and photogrammetric records
11 pages; International audience; The present study evaluates a methodological workflow that could identify dinosaur tracks and trackways more comprehensively at outcrop scale. The approach described here is based both on 3D modelling by photogrammetry at different resolutions, and on suitably processed digital elevation models (DEMs). The ichnosite of Anza, Morocco, was chosen to demonstrate the efficiency of the proposed pipeline, because 323 dinosaur and pterosaur tracks discovered there have already been published. One subsector containing 89 tracks, identified in the two companion works that followed a traditional approach, was selected and divided into four subzones. By combining diff…
Lichens Used as Monitors of Atmospheric Pollution Around Agadir (Southwestern Morocco)—A Case Study Predating Lead-Free Gasoline
More than 30 epiphytic lichens, collected in Agadir (Morroco) and along a 150-km transect from the Atlantic Ocean eastward, were analyzed for their metal content and lead isotopic composition. This dataset was used to evaluate atmospheric metal contamination and the impact of the city on the surrounding area. The concentrations of Cu, Pb, and Zn (average ± 1 SD) were 20.9 ± 15.2 μg g−1, 13.8 ± 9.0 μg g−1, and 56.6 ± 26.6 μg g−1, respectively, with the highest values observed in lichens collected within the urban area. The 206Pb/207Pb and 208Pb/207Pb ratios in the lichens varied from 1.146 to 1.186 and from 2.423 to 2.460, respectively. Alkyllead-gasoline sold in Morocco by the major petrol …
North Atlantic Ice‐Rafting, Ocean and Atmospheric Circulation During the Holocene: Insights From Western Mediterranean Speleothems
In this study, we present a Holocene rainfall index based on three high-resolution speleothem records from the Western Mediterranean, a region under the influence of the westerly winds belt modulated by the North Atlantic Oscillation (NAO). On centennial to millennial timescales, we show that the North Atlantic ice-rafting events were likely associated with negative NAO-like conditions during the Early Holocene and the Late Holocene. However, our data reveal that this is not clearly the case for the mid-Holocene ice-rafting events, during which we also show evidence of positive NAO-like patterns from other paleo-oceanographic and paleo-atmospheric data. Hence, contradictory mechanisms invol…
Speleothem records decadal to multidecadal hydroclimate variations in southwestern Morocco during the last millennium
Abstract This study presents the first well-dated high resolution stable isotope ( δ 18 O and δ 13 C ) and trace element (Mg and Sr) speleothem records from southwestern Morocco covering the last 1000 yrs. Our records reveal substantial decadal to multidecadal swings between dry and humid periods, consistent with regional paleorecords with prevailing dry conditions during the Medieval Climate Anomaly (MCA), wetter conditions during the second part of the Little Ice Age (LIA), and a trend towards dry conditions during the current warm period. These coherent regional climate signals suggest common climate controls. Statistical analyses indicate that the climate of southwestern Morocco remaine…