scholarly journals Trace element abundance in agate.

1994 ◽  
Vol 28 (4) ◽  
pp. 359-362
Author(s):  
Tsuyoshi Tanaka ◽  
Hikari Kamioka
Keyword(s):  
Trace Element ◽  
Element Abundance ◽  
Trace Element Abundance

scholarly journals Mapping salinization and trace element abundance (including As and other metalloids) in the groundwater of north-central Mexico using a double-clustering approach

2021 ◽  
Vol 205 ◽  
pp. 117709
Author(s):  
Abrahan Mora ◽  
Juan Antonio Torres-Martínez ◽  
Cristina Moreau ◽  
Guillaume Bertrand ◽  
Jürgen Mahlknecht
Keyword(s):  
Trace Element ◽  
Element Abundance ◽  
Central Mexico ◽  
Trace Element Abundance ◽  
North Central ◽  
Clustering Approach ◽  
Double Clustering

scholarly journals The composition of subduction zone fluids and the origin of the trace element enrichment in arc magmas

2021 ◽  
Vol 176 (7) ◽  
Author(s):  
Greta Rustioni ◽  
Andreas Audetat ◽  
Hans Keppler
Keyword(s):  
Trace Element ◽  
Major And Trace Elements ◽  
The Other ◽  
Element Abundance ◽  
Abundance Pattern ◽  
Piston Cylinder ◽  
Other Hand ◽  
Fluid Fraction ◽  
Element Enrichment ◽  
Trace Element Enrichment

AbstractThe partitioning of major and trace elements between eclogite and aqueous fluids with variable salinity was studied at 700–800 °C and 4–6 GPa in piston cylinder and multi anvil experiments. Fluid compositions were determined using the diamond trap technique combined with laser ablation ICP-MS measurements in the frozen state. In addition to NaCl, SiO2 is the main solute in the fluids. The fluid/eclogite partition coefficients of the large ion lithophile elements (LILE), such as Rb, Cs, Sr, and Ba as well as those of the light rare earths (LREE), of Pb, and of U increase by up to three orders of magnitude with salinity. These elements will therefore be efficiently transported by saline fluids. On the other hand, typical high field strength elements, such as Ti, Nb, and Ta, are not mobilized even at high salinities. Increasing temperature and pressure gradually increases the partitioning into the fluid. In particular, Th is mobilized by silica-rich fluids at 6 GPa already at low salinities. We show that we can fully reproduce the trace element enrichment pattern of primitive arc basalts by adding a few percent of saline fluid (with 5–10 wt% Cl) released from the basaltic slab to the zone of melting in the mantle wedge. Assuming 2 wt% of rutile in the eclogite equilibrated with the saline fluid produces a negative Nb Ta anomaly that is larger than in most primitive arc basalts. Therefore, we conclude that the rutile fraction in the subducted eclogite below most arcs is likely < 1 wt%. In fact, saline fluids would even produce a noticeable negative Nb Ta anomaly without any rutile in the eclogite residue. Metasomatism by sediment melts alone, on the other hand, is unable to produce the enrichment pattern seen in arc basalts. We, therefore, conclude that at least for primitive arc basalts, the release of hydrous fluids from the basaltic part of the subducted slab is the trigger for melting and the main agent of trace element enrichment. The contribution of sediment melts to the petrogenesis of these magmas is likely negligible. In the supplementary material, we provide a “Subduction Calculator” in Excel format, which allows the calculation of the trace element abundance pattern in primitive arc basalts as function of fluid salinity, the amount of fluid released from the basaltic part of the subducted slab, the fluid fraction added to the source, and the degree of melting.

scholarly journals Condensation Chemistry of Circumstellar Grains

1999 ◽  
Vol 191 ◽  
pp. 279-290 ◽  
Author(s):  
Katharina Lodders ◽  
Bruce Fegley
Keyword(s):  
Trace Element ◽  
Total Pressure ◽  
Element Abundance ◽  
Elemental Abundances ◽  
Trace Element Chemistry ◽  
Abundance Patterns ◽  
Element Chemistry ◽  
Circumstellar Shells ◽  
Thermochemical Equilibrium ◽  
Equilibrium Calculations

Thermochemical equilibrium calculations are successful in predicting the mineralogy as well as the major and trace element chemistry of circumstellar grains found in meteorites. The calculations also explain observations of dust close to AGB stars (within 1–3 stellar radii). The trace element chemistry in circumstellar graphite, SiC, and other refractory carbide grains agrees with equilibrium condensation calculations for circumstellar shells of carbon stars. Observed trace element abundance patterns in N stars are complementary to those found in SiC grains indicating fractional condensation in circumstellar shells. Condensation temperatures depend upon total pressure, C/O ratio, nitrogen abundances, and overall metallicity. Therefore for condensation temperatures to be meaningful, the total pressure and elemental abundances (i.e., C/O ratio, metallicity) must be specified.

Sign in / Sign up

Export Citation Format

Share Document