Trace metal

About: Trace metal is a research topic. Over the lifetime, 5125 publications have been published within this topic receiving 181046 citations.

A possible capture of molybdenum during early diagenesis of dysoxic sediments

Abstract: Molybdenum is a trace metal commonly used as a marker of paleoredox conditions of ancient depositional settings. Pyrite is an important molybdenum (Mo) host for enriched sedimentary rocks. In this paper we study the relationship between Mo and pyrite in the Bancs Jumeaux Formation, a Jurassic succession in northern France consisting of limestone and pyrite-rich marls. This formation is relatively enriched in Mo compared to other redox-sensitive trace metals. Our approach is grounded on bulk rock chemical analysis and delineation of two contrasting types of pyrite that can be extracted from the rocks: polyframboids and nonframboidal concretionary masses. The morphological characteristics of both morphotypes were studied using scanning electronic microscopy. The polyframboids are richer in Mo than the concretions but are not markedly enriched in other trace metals. This discrepancy in geochemical composition could result from pyrite precipitation at different times during early diagenesis. Our results tend to indicate that the polyframboids would have formed very early in reducing “microniches”, within dominantly dysoxic sediment. This early pyrite precipitation occurred at shallow depth below the sediment-water interface close to the abundant Mo source in overlying oxic seawater (molybdate ions), and would have fostered Mo-capture by the polyframboids in relatively large amounts. The concretions would have formed later during early diagenesis (within the sulfidic zone) under conditions of more limited Mo availability.

Trace metal concentrations in the surf zone and in coastal waters off Baja California, Mexico

Abstract: Pronounced spatial gradients were observed in trace element concentrations (Cd, Co, Cu, and Ni) in nearshore surf zone (<100 m offshore) and coastal (5−45 km offshore) waters off Baja California, Mexico. The ranges of metal concentrations in those waters were 0.034−0.26 nM for Cd, 0.022−0.59 nM for Co, 0.93−3.6 nM for Cu, and 3.6−6.4 nM for Ni. Metal concentrations exhibited offshore gradients, with the highest levels nearshore. Metal:salinity, metal:nutrient, and metal:metal relationships indicated that the relatively high nearshore concentrations were caused by upwelling (Cd and Ni) and by benthic particle resuspension and diagenetic remobilization (Co and Cu). The relatively low offshore concentration levels appeared to be caused, in part, by the intrusion of oceanic waters from the North Pacific Central Gyre, as evidenced by similarities in the molar ratios of Ag:Cu in coastal waters off Baja California (9.0 × 10-3) and in subtropical oceanic waters off central Mexico (9.6 × 10-3). This was also consi...

Extraction of trace metals from fly ash

Abstract: A process for recovering silver, gallium and/or other trace metals from a fine grained industrial fly ash associated with a process for producing phosphorous, the fly ash having a silicate base and containing surface deposits of the trace metals as oxides, chlorides or the like, with the process being carried out by contacting the fly ash with AlCl 3 in an alkali halide melt to react the trace metals with the AlCl 3 to form compositions soluble in the melt and a residue containing the silicate and aluminum oxide or other aluminum precipitate, and separating the desired trace metal or metals from the melt by electrolysis or other separation techniques.