Imbalance in the oceanic strontium budget

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doi: 10.1016/S0012-821X(03)00191-2
Author(s): Davis, Amy C.; Bickle, Mike J.; Teagle, Damon A. H.
Author Affiliation(s): Primary:
University of Cambridge, Department of Earth Sciences, Cambridge, United Kingdom
Other:
University of Southampton, United Kingdom
Volume Title: Earth and Planetary Science Letters
Source: Earth and Planetary Science Letters, 211(1-2), p.173-187. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0012-821X CODEN: EPSLA2
Note: In English. 80 refs.; illus., incl. 3 tables
Summary: Palmer and Edmond [Earth Planet. Sci. Lett. 92 (1989) 11-26] indicated that thermally plausible oceanic hydrothermal inputs of strontium to the oceans are not sufficient to balance the riverine input. It has recently been suggested that off-axis low-temperature hydrothermal circulation may reconcile this discrepancy [e.g. Butterfield et al., Geochim. Cosmochim. Acta 65 (2001) 4141-4153]. Strontium isotope alteration profiles are compiled for sampled in situ ocean and ophiolite crust to calculate a sustainable cumulative hydrothermal flux to the oceanic strontium budget. High-temperature circulation contributes ∼1.8×109 mol yr-1 of basaltic strontium to the oceans. Enhanced hydrothermal systems in arc-related spreading environments (10% of the crust) may increase this to ∼2.3×109 mol yr-1. It is shown that low-temperature flow cannot supply the remaining flux required to reconcile the oceanic strontium budget (∼8.7×109 mol yr-1) because this would require 100% exchange of seawater strontium for basaltic strontium over an 820 m section of MORB-like crust. Currently sampled in situ ocean crust is not altered to this extent. The isotopic alteration intensity of 120 Myr crust sampled in DSDP Holes 417D and 418A indicates that off-axis low-temperature flow may contribute up to ∼8×108 mol yr-1 of basaltic strontium (9% of that required). The ocean crust can sustain a total basaltic strontium flux of ∼3.1±0.8×109 mol yr-1 (87Sr/86Sr ∼0.7025) to the oceans. This is consistent with hydrothermal flux estimates, but remains less than a third of the flux required to balance the oceanic strontium budget. The ocean crust cannot support a higher hydrothermal contribution unless the average ocean crust is significantly more altered than current observation. Abstract Copyright (2003) Elsevier, B.V.
Year of Publication: 2003
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
ODP Ocean Drilling Program
Key Words: 02 Geochemistry; Alkaline earth metals; Arabian Peninsula; Asia; Atlantic Ocean; Crust; Cyprus; DSDP Site 417; DSDP Site 418; DSDP Site 504; Deep Sea Drilling Project; Geochemical cycle; Geochemical profiles; Geochemistry; Hydrothermal alteration; IPOD; Indian Ocean; Isotope ratios; Isotopes; Leg 102; Leg 111; Leg 137; Leg 140; Leg 148; Leg 51; Leg 52; Leg 53; Leg 69; Leg 70; Leg 83; Leg 92; Mass balance; Metals; Metasomatism; Middle East; ODP Site 896; Ocean Drilling Program; Oceanic crust; Oman; Ophiolite; Ophiolite complexes; Pacific Ocean; Sr-87/Sr-86; Stable isotopes; Strontium; Water-rock interaction; Whole rock
Coordinates: N011335 N011338 W0834348 W0834357
N011301 N011301 W0834323 W0834323
N250205 N250207 W0680326 W0680327
N250000 N250000 W0680000 W0680000
Record ID: 2003050861
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands