Variations in Trace Element Contents and Isotopic Compositions of Lower Cretaceous Carbonates from the Galicia Margin (ODP Leg 103): Reconstruction of the Paleochemistry of the Early Cretaceous Ocean

Abstract

Trace element contents (Sr, Mg, Mn, and Fe) and the composition of oxygen and carbon isotopes show that late burial diagenesis did not play an important role in pelagic carbonate chemistry in the bulk carbonates recovered from Holes 638B, 638C, and 641C (except for anoxic pore-water diagenesis in Valanginian sediments). The evolution of these different geochemical markers documents the importance and global extent of the Barremian ocean chemistry crisis. A reconstruction of paleoceanographic and climatic conditions during the Early Cretaceous is proposed. Sea level rose eustatically from the early Hauterivian to early Albian, but a rapid down and up fluctuation occurred during the Barremian. Soluble supply from the continent decreased during the Valanginian-early Hauterivian while oceanic hydrothermal supply increased. The climate cooled slightly during the Hauterivian, rapidly warmed during the Barremian, and cooled again during the Aptian.

Carbon-Isotope Stratigraphy and Paleoceanographic Significance of the Lower Cretaceous Shallow-Water Carbonates of Resolution Guyot, Mid-Pacific Mountains

“…Carbon-isotope curves from Hauterivian through Aptian deep-sea carbonates have been reported from a number of Atlantic deep-sea drilling sites, and from southern France, Italy, and Switzerland in the Tethyan region (Arthur et al, 1979;Létolle et al, 1979;Weissert et al, 1985;Clauser et al, 1988;Weissert and Bréhéret, 1991;Weissert and Lini, 1991). They show relatively consistent trends.…”

New insights into geochemical behaviour in ancient marine carbonates (Upper Jurassic Ammonitico Rosso): Novel proxies for interpreting sea‐level dynamics and palaeoceanography

“…In addition, relative acidification related to hydrothermal CO 2 inflows would most probably retard Fe precipitation. In this way, long‐range transport (up to hundreds of kilometres) of soluble iron can account for higher Fe concentrations, as recorded for Aptian pelagic carbonates (1000 to 2000 p.p.m., Clauser et al ., ) in areas distant from hydrothermal vent systems (up to 2000 km away from the source, Wu et al ., ). The mean value obtained (1200 p.p.m.)…”

Mass-Transfer and Fluid Flow along Extensional Detachment Faults in Hyperextended Rift Systems: The Examples of Tasna in the Alps, Mauléon in the Pyrenees, and Hobby High Offshore Iberia

“…The analyses of serpentinized peridotites and their minerals were from Müntener et al [70], who used the approach and laboratory (SARM-Nancy) described above. The whole-rock analysis of fault rocks from Iberia was conducted using the shipboard X-ray fluorescence [46] and the data from sedimentary rocks were obtained using X-ray diffraction (see [71]).…”

“…Geochemical results from Clauser et al [71] sampled on the ODP Sites 638B and 641C (Figure 1a) are used to evaluate if there is a fluid signature in the sedimentary rocks related to the formation of hyperextended domains and exhumation of mantle rocks (Figure 10). The existing compounds or ratios were used as follows:…”