Dataset Information

Tiny droplets of ocean island basalts unveil Earth's deep chlorine cycle.

ABSTRACT: Fully characterising the exchange of volatile elements between the Earth's interior and surface layers has been a longstanding challenge. Volatiles scavenged from seawater by hydrothermally altered oceanic crust have been transferred to the upper mantle during subduction of the oceanic crust, but whether these volatiles are carried deeper into the lower mantle is poorly understood. Here we present evidence of the deep-mantle Cl cycle recorded in melt inclusions in olivine crystals in ocean island basalts sourced from the lower mantle. We show that Cl-rich melt inclusions are associated with radiogenic Pb isotopes, indicating ancient subducted oceanic crust in basalt sources, together with lithophile elements characteristic of melts from a carbonated source. These signatures collectively indicate that seawater-altered and carbonated oceanic crust conveyed surface Cl downward to the lower mantle, forming a Cl-rich reservoir that accounts for 13-26% or an even greater proportion of the total Cl in the mantle.

SUBMITTER: Hanyu T

PROVIDER: S-EPMC6320363 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Tiny droplets of ocean island basalts unveil Earth's deep chlorine cycle.

Hanyu Takeshi T Shimizu Kenji K Ushikubo Takayuki T Kimura Jun-Ichi JI Chang Qing Q Hamada Morihisa M Ito Motoo M Iwamori Hikaru H Ishikawa Tsuyoshi T

Nature communications 20190104 1

Fully characterising the exchange of volatile elements between the Earth's interior and surface layers has been a longstanding challenge. Volatiles scavenged from seawater by hydrothermally altered oceanic crust have been transferred to the upper mantle during subduction of the oceanic crust, but whether these volatiles are carried deeper into the lower mantle is poorly understood. Here we present evidence of the deep-mantle Cl cycle recorded in melt inclusions in olivine crystals in ocean islan ...[more]

PMID: 30610195

Similar Datasets

Project description:Modern biological dependency on trace elements is proposed to be a consequence of their enrichment in the habitats of early life together with Earth's evolving physicochemical conditions; the resulting metallic biological complement is termed the metallome. Herein, we detail a protocol for describing metallomes in deep time, with applications to the earliest fossil record. Our approach extends the metallome record by more than 3 Ga and provides a novel, non-destructive method of estimating biogenicity in the absence of cellular preservation. Using microbeam particle-induced X-ray emission (µPIXE), we spatially quantify transition metals and metalloids within organic material from 3.33 billion-year-old cherts of the Barberton greenstone belt, and demonstrate that elements key to anaerobic prokaryotic molecular nanomachines, including Fe, V, Ni, As and Co, are enriched within carbonaceous material. Moreover, Mo and Zn, likely incorporated into enzymes only after the Great Oxygenation Event, are either absent or present at concentrations below the limit of detection of µPIXE, suggesting minor biological utilisation in this environmental setting. Scanning and transmission electron microscopy demonstrates that metal enrichments do not arise from accumulation in nanomineral phases and thus unambiguously reflect the primary composition of the carbonaceous material. This carbonaceous material also has δ13C between -41.3‰ and 0.03‰, dominantly -21.0‰ to -11.5‰, consistent with biological fractionation and mostly within a restricted range inconsistent with abiotic processes. Considering spatially quantified trace metal enrichments and negative δ13C fractionations together, we propose that, although lacking cellular preservation, this organic material has biological origins and, moreover, that its precursor metabolism may be estimated from the fossilised "palaeo-metallome". Enriched Fe, V, Ni and Co, together with petrographic context, suggests that this kerogen reflects the remnants of a lithotrophic or organotrophic consortium cycling methane or nitrogen. Palaeo-metallome compositions could be used to deduce the metabolic networks of Earth's earliest ecosystems and, potentially, as a biosignature for evaluating the origin of preserved organic materials found on Mars.

Dataset Information

Tiny droplets of ocean island basalts unveil Earth's deep chlorine cycle.

Publications

Tiny droplets of ocean island basalts unveil Earth's deep chlorine cycle.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets