Trace Elements in Marine Sediments from the Oxfordian (Late Jurassic): Implications for Seawater Chemistry, Erosional Processes, Changes in Oceanic Circulation and More

Abstract

Abstract:The Oxfordian, first stage of the late Jurassic, is remarkably variable in terms of deposited sediments, geochemical tracers, and climate. The climate changed during the Middle Oxfordian from humid to arid with a temperature rise of more than five degrees. During this time, the 13 C reached maximum values. The positive excursion in 13 C of carbonates from the Oxfordian (with an amplitude of more than 1‰) was reproduced in hemipelagic sections from southeastern France. Analysis of major and trace elements of these carbonates were carried out by LA-ICP-MS in order to verify their application as palaeoproxies in conjunction with the changes mentioned in climate. As a novel approach 36 elements were measured with regard to establish a complete and comprehensive analysis of the geochemical situation. Concentration peaks of P, Sr, Mn, Fe, Ba point to a more oligotrophic setting within the lower part of the sediment profile from southeastern France. Conversely, the positive 13 C excursion with 13 C values rising from 2 to 3 ‰ within the uppermost part of the profile coincide with more elevated concentrations of V, Fe, Mn, U arguing for an ocean-wide anoxia (Oceanic Anoxic Events OAE). High detrital input during this arid period is recorded by enhanced concentrations of elements like Ti, Mn, Fe, Zr, Nb and W. This correlation of the 13 C excursion with trends in Ti, Nb, W as well as Mn and Fe contents reflects changes in the Oxfordian palaeooceanography and climate. During the late Oxfordian the environmental prerequisites were controlled by warm and arid conditions and an increased metal flux from the continent due to the intensified chemical and physical weathering, erosion of rocks, as well as aeolian and fluvial transport to the oceans.

Uptake of Barium from Vermiculite by the Bacterium Pseudomonas fluorescens - New Indications for Barium as a Palaeoproxy

“…All trace elements with the exception of barium were presented and discussed in Müller [66]. The results of the analyses of barium are published separately because of the significance of this element as a palaeoproxy.…”

Uranium quantification of oak tree rings (Quercus petraea) from a former uranium mining site by High Resolution Inductively Coupled Plasma Mass spectrometry in Laser Ablation and Solution modes

“…Further studies are needed to gain more complete information. Nonetheless, an inhomogeneous elemental distribution leads to poor measurement precision and can result in a non-representative sampling by laser [53]. Data accuracy and interpretation (i.e.…”