Water in enstatite from Mid-Atlantic Ridge peridotite: evidence for the water content of suboceanic mantle?

Autor(en)

Anton Beran, Esther Schmädicke, Jürgen Gose

Abstrakt

We present the first water concn. data for oceanic mantle peridotite. The rocks come from the Mid-Atlantic Ridge and were sampled by drilling during Leg 153 of the Ocean Drilling Program. Earlier studies of peridotite xenoliths suggest that orthopyroxene is the most important host of water in the upper mantle. However, an unresolved question is whether the measured water content in orthopyroxene is equal to its original concn. in the mantle or possibly lower because of decompression-related water loss. Our investigations of oceanic mantle rocks yield water contents in orthopyroxene in the range between 160 and 270 ppm by wt. (wt). These new data, compared with those from xenoliths, exptl. studies, and geophys. investigations, imply that the measured values reflect the original mantle contents. The preservation of mantle water contents is ascribed to an exhumation mechanism that provides for cooling during ascent of the suboceanic mantle slices.

Organisation(en)

Institut für Mineralogie und Kristallographie

Externe Organisation(en)

Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)

Journal

Geology

Band

37

Seiten

543-546

Anzahl der Seiten

4

ISSN

0091-7613

Publikationsdatum

2009

Peer-reviewed

Ja

ÖFOS 2012

1030 Physik, Astronomie, 105116 Mineralogie

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/ab900104-1b05-46db-ac4c-c6c2ff44e441