scholarly journals The Fluid Mobilities of K and Zr in Subduction Zones: Thermodynamic Constraints

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 394
Author(s):  
Richen Zhong ◽  
Min Zhang ◽  
Chang Yu ◽  
Hao Cui
Keyword(s):  
Trace Element ◽  
Subduction Zones ◽  
Critical Role ◽  
High Field Strength ◽  
Trace Element Pattern ◽  
Arc Magmas ◽  
Thermodynamic Simulations ◽  
Element Pattern ◽  
Element Transfer ◽  
Complex Ion

A subduction zone plays a critical role in forging continental crust via formation of arc magmas, which are characteristically enriched in large ion lithophile elements (LILEs) and depleted in high field strength elements (HFSEs). This trace element pattern results from the different mobilities of LILEs and HFSEs during slab-to-wedge mass transfer, but the mechanisms of trace element transfer from subducting crusts are not fully understood. In this study, thermodynamic simulations are carried out to evaluate the mobilities of K and Zr, as representative cases of LILE and HFSE, respectively, in slab fluids. The fluids buffered by basaltic eclogite can dissolve > 0.1 molal of K at sub-arc depths (~3 to 5.5 GPa). However, only minor amounts of K can be liberated by direct devolatilization of altered oceanic basalt, because sub-arc dehydration mainly takes place at temperatures < 600 °C (talc-out), wherein the fluid solubility of K is very limited (<0.01 molal). Therefore, serpentinite-derived fluids are required to flush K from the eclogite. The solubility of K can be enhanced by the addition of NaCl to the fluid, because fluid Na+ can unlock phengite-bonded K via a complex ion exchange. Finally, it is further confirmed that Zr and other HFSEs are immobile in slab fluids.

scholarly journals The role of sulphur on the melting of Ca-poor sediment and on trace element transfer in subduction zones: an experimental investigation

2021 ◽  
Author(s):  
Anne-Aziliz Pelleter ◽  
Gaëlle Prouteau ◽  
Bruno Scaillet
Keyword(s):  
Trace Element ◽  
Partial Melting ◽  
Subduction Zones ◽  
Sediment Flux ◽  
Arc Magmas ◽  
Trace Element Contents ◽  
The Stability ◽  
Element Transfer ◽  
High Sediment

Abstract We performed phase equilibrium experiments on a natural Ca-poor pelite at 3 GPa, 750-1000 °C, under moderately oxidizing conditions, simulating the partial melting of such lithologies in subduction zones. Experiments investigated the effect of sulphur addition on phase equilibria and compositions, with S contents of up to ∼ 2.2 wt. %. Run products were characterized for their major and trace element contents, in order to shed light on the role of sulphur on the trace element patterns of melts produced by partial melting of oceanic Ca-poor sediments. Results show that sulphur addition leads to the replacement of phengite by biotite along with the progressive consumption of garnet, which is replaced by an orthopyroxene-kyanite assemblage at the highest sulphur content investigated. All Fe-Mg silicate phases produced with sulphur, including melt, have higher MgO/(MgO+FeO) ratios (relative to S-free/poor conditions), owing to Fe being primarily locked up by sulphide in the investigated redox range. Secular infiltration of the mantle wedge by such MgO and K2O-rich melts may have contributed to the Mg and K-rich character of the modern continental crust. Addition of sulphur does not affect significantly the stability of the main accessory phases controlling the behaviour of trace elements (monazite, rutile and zircon), although our results suggest that monazite solubility is sensitive to S content at the conditions investigated. The low temperature (∼ 800 °C) S-bearing and Ca-poor sediment sourced slab melts show Th and La abundances, Th/La systematics and HFSE signatures in agreement with the characteristics of sediment-rich arc magmas. Because high S contents diminish phengite and garnet stabilities, S-rich and Ca-poor sediment sourced slab melts have higher contents of Rb, B, Li (to a lesser extent), and HREE. The highest ratios of La/Yb are observed in sulphur-poor runs (with a high proportion of garnet, which retains HREE) and beyond the monazite out curve (which retains LREE). Sulphides appear to be relatively Pb-poor and impart high Pb/Ce ratio to coexisting melts, even at high S content. Overall, our results show that Phanerozoic arc magmas from high sediment flux margins owe their geochemical signature to the subduction of terrigenous, sometimes S-rich, sediments. In contrast, subduction of such lithologies during Archean appears unlikely or unrecorded.

Petrographic, Geochemical and Isotopic (Sr–Nd–Pb–Os) Study of Plio-Quaternary Volcanics and the Tertiary Basement in the Jorullo-Tacámbaro Area, Michoacán-Guanajuato Volcanic Field, Mexico

2019 ◽  
Vol 60 (12) ◽  
pp. 2317-2338 ◽  
Author(s):  
Marie-Noëlle Guilbaud ◽  
Claus Siebe ◽  
Christine Rasoazanamparany ◽  
Elisabeth Widom ◽  
Sergio Salinas ◽  
...  
Keyword(s):  
Trace Element ◽  
Crustal Contamination ◽  
Volcanic Belt ◽  
Volcanic Field ◽  
Calc Alkaline ◽  
Trace Element Pattern ◽  
Alkaline Rocks ◽  
Rock Types ◽  
Oceanic Sediments ◽  
Element Pattern

Abstract The origin of the large diversity of rock types erupted along the subduction-related Trans-Mexican Volcanic Belt (TMVB) remains highly debated. In particular, several hypotheses have been proposed to explain the contemporary eruption of calc-alkaline and alkaline magmas along the belt. The Michoacán-Guanajuato Volcanic Field (MGVF) is an atypical, vast region of monogenetic activity located in the western-central part of the TMVB. Here we present new petrographic, geochemical, and isotopic (Sr–Nd–Pb–Os) data on recent volcanics in the Jorullo-Tacámbaro area that is the closest to the oceanic trench. TMVB-related volcanics in this area are Plio-Quaternary (&lt;5 Ma) and mainly form a calc-alkaline series from basalts to dacites, with rare (&lt;5 vol. %) alkaline rocks that range from trachybasalts to trachydacites, and transitional samples. Crystal textures are consistent with rapid crystallization at shallow depth and processes of mixing of similar magma batches (magma recharge). All of the samples exhibit an arc-type trace element pattern. Alkaline and transitional magmas have higher Na2O and K2O, lower Al2O3, and higher concentrations in incompatible elements (e.g. Sr, K, Ba, Th, Ce, P) compared to calc-alkaline rocks. Calc-alkaline rocks are similar isotopically to transitional and alkaline samples, except for a few low 87Sr/86Sr samples. Sr, Nd and Pb isotopes do not correlate with MgO or 187Os/188Os, indicating that they were not significantly influenced by crustal contamination. Isotopic and trace-element systematics suggest that the Tacámbaro magmas are produced by melting of a mantle wedge fluxed by fluids derived from a mixture of subducted sediments and altered oceanic crust. Alkaline and transitional magmas can be derived from a lower degree of partial melting of a similar source to that of the calc-alkaline rocks, whereas the few low 87Sr/86Sr calc-alkaline rocks require a lower proportion of fluid derived from oceanic sediments and crust. Volcanism at the trenchward edge of the MGVF was thus driven purely by subduction during the last 5 Ma, hence discarding slab rollback in this sector of the TMVB.

Distinguishing High- from Low-Temperature Platinum Nuggets Through Their Trace-Element Pattern

2019 ◽  
Vol 114 (2) ◽  
pp. 201-206
Author(s):  
Alexandre Raphael Cabral ◽  
Thomas Zack ◽  
Stephan König ◽  
Benjamin Eickmann ◽  
Rogerio Kwitko-Ribeiro ◽  
...  
Keyword(s):  
Low Temperature ◽  
Trace Element ◽  
Trace Element Pattern ◽  
Element Pattern

Bone trace element pattern in an 18th century population sample of tenerife (Canary islands)

1998 ◽  
Vol 65 (1) ◽  
pp. 45-51 ◽  
Author(s):  
M. Arnay-de-la-Rosa ◽  
E. Gonzalez-Reimers ◽  
J. Velasco-Vazquez ◽  
N. Barros-Lopez ◽  
L. Galindo-Martin
Keyword(s):  
Trace Element ◽  
Canary Islands ◽  
18Th Century ◽  
Population Sample ◽  
Trace Element Pattern ◽  
Element Pattern

scholarly journals Mineralogy, Geochemistry and Genesis of the Luc Yen Noble Spinel Deposit, Vietnam

2019 ◽  
Vol 5 ◽  
pp. 56-69
Author(s):  
K.A. Kuksa ◽  
P.B. Sokolov ◽  
O.Yu. Marakhovskaya ◽  
G.A. Gussias ◽  
W. Brownscombe
Keyword(s):  
Trace Element ◽  
Trace Element Geochemistry ◽  
Element Geochemistry ◽  
Trace Element Pattern ◽  
Mineral Inclusions ◽  
Icp Ms ◽  
Element Pattern ◽  
Mineral Assemblages ◽  
North Vietnam ◽  
Petrographic Study

The paper presents the detailed mineralogical and petrographic study of spinel-bearing marbles at the Luc Yen deposit, North Vietnam. The LA-ICP-MS analysis of 74 spinel grains, combined with mineralogical data, allows us to discriminate them into fve types according to mineral assemblages and trace element geochemistry. Forty seven minerals are identifed as inclusions in spinel grains and 38 minerals are described at Luc Yen deposit for the frst time including leonardsenite, tintisite, manasseite, chalcoalumite, cobaltite and spherocobaltite. The mineral assemblages, trace element pattern, and specifc mineral inclusions indicate the involvement of hydrothermal fuids related to magma intrusions in the formation of, at least, two of fve spinel types at the deposit.

Determination and evaluation of a trace element pattern in urine of clinical origin by ICP-MS

2004 ◽  
Vol 21 (07) ◽  
pp. 159-167
Author(s):  
C. Bertram ◽  
R. Brandt ◽  
N. Jakubowski ◽  
M. Amend
Keyword(s):  
Trace Element ◽  
Trace Element Pattern ◽  
Icp Ms ◽  
Element Pattern

The trace element pattern in occupational lead exposed workers

2015 ◽  
Vol 238 (2) ◽  
pp. S147-S148 ◽  
Author(s):  
M.E. Alagüney ◽  
C. Bal ◽  
A. Hocaoglu ◽  
M. Büyükşekerci ◽  
L. Tutkun ◽  
...  
Keyword(s):  
Trace Element ◽  
Trace Element Pattern ◽  
Element Pattern ◽  
Exposed Workers

Trace element pattern in patients with fibromyalgia

2007 ◽  
Vol 385 (1-3) ◽  
pp. 20-27 ◽  
Author(s):  
I ROSBORG ◽  
E HYLLEN ◽  
J LIDBECK ◽  
B NIHLGARD ◽  
L GERHARDSSON
Keyword(s):  
Trace Element ◽  
Trace Element Pattern ◽  
Element Pattern

An iridium anomaly in the Ludlow Bone Bed from the Upper Silurian, England

1992 ◽  
Vol 129 (3) ◽  
pp. 359-362 ◽  
Author(s):  
B. Schmitz
Keyword(s):  
Trace Element ◽  
Sea Water ◽  
Impact Event ◽  
Brazos River ◽  
High Concentration ◽  
Trace Element Pattern ◽  
Asteroid Impact ◽  
Storm Deposit ◽  
Element Pattern ◽  
Upper Silurian

AbstractThe Ludlow Bone Bed in the Upper Silurian of the Welsh Borderland shows an anomalously high concentration of iridium (0.49 ppb) compared with background (0.040 ppb Ir). Considering the overall major and trace element pattern and the mineralogy of the bone bed, it appears that the bulk of their has precipitated from sea water and is not primarily related to an asteroid impact event. A secondary relation of the Ir to such an event, however, cannot be excluded. The profound sedimentological similarity (skeletal sands and hummocky cross-stratification) between the Ir-carrying ‘storm deposit’ at the Cretaceous–Tertiary boundary at Brazos River, Texas, and the LBB and overlying sediments may indicate such a relation.

Sign in / Sign up

Export Citation Format

Share Document