0000000000648174
AUTHOR
Johan Yans
showing 3 related works from this author
Distribution of trace elements in willemite from the Belgium non-sulphide deposits
2019
Samples of willemite (Zn2SiO4) mineralization from the historical non-sulphide Zn–Pb deposits of La Calamine (eastern Belgium) have been recovered from collections of the Geological Survey of Belgium. Textural and chemical analyses are used to evaluate the critical element distribution (Ge, In, Ga) and deportment. willemite occurs as a variety of types that continuously formed between the protore stage (sulphides) and the late supergene stage (carbonates and hydrated phases). Different types of willemite may be distinguished on the basis of their shape and zoning characteristics, supporting a polyphase non-sulphide mineralization after the protore stage. This is also marked by a significant…
Unravelling the PETM record in the Sparnacian facies of NW Europe: new data from the north-eastern Paris Basin
2010
The geological archives record "hyperthermic" crises, along with their consequences on the biota and physical environment. Among these, the PETM (Paleocene-Eocene Thermal Maximum) is considered as the closest analogue to the current climate crisis due to its global character and the speeds at which the CO2 rate and average temperatures increased. Some 55.8 Ma ago (Aubry et al., 2007), it affected the Earth for a period of almost 200,000 years; the terrestrial and marine paleoenvironments were marked by a negative δ13C anomaly (or Carbon Isotopic Excursion, CIE) coinciding with a negative δ18O anomaly indicative of a drastic temperature rise (+ 3 to + 8 °C). The causes envisaged to explain t…
The PETM record revealed by a new integrated high-resolution dinoflagellate cyst and geochemical data from the "Sparnacian" sediments in the Paris an…
2012
International audience; The Paris Basin represents an historical cradle of the Paleogene stratigraphy, where the Paleocene Epoch and the "Sparnacian Stage" have been erected (Schimper, 1874; Dollfus, 1880). As highlighted by Aubry et al. (2005), whereas the chronostratigraphic connotation of the Sparnacian Stage occurred to be controversial since its definition, modern studies of the Late Paleocene - Early Eocene interval have revealed that the so-called "Sparnacian" deposits encompass a remarkable and short (~170 kyr) episode in the Cenozoic history, the Paleocene-Eocene Thermal Maximum (PETM, ~55.8-55.6 Ma). However, due to a large development of diverse and laterally variable, predominan…