High-temperature water-rock interactions and hydrothermal environments in the chondrite-like core of Enceladus.
It has been suggested that Saturn's moon Enceladus possesses a subsurface ocean. The recent discovery of silica nanoparticles derived from Enceladus shows the presence of ongoing hydrothermal reactions in the interior. Here, we report results from detailed laboratory experiments to constrain the reaction conditions. To sustain the formation of silica nanoparticles, the composition of Enceladus' core needs to be similar to that of carbonaceous chondrites. We show that the presence of hydrothermal reactions would be consistent with NH3- and CO2-rich plume compositions. We suggest that high reaction temperatures (>50 °C) are required to form silica nanoparticles whether Enceladus' ocean is chemically open or closed to the icy crust. Such high temperatures imply either that Enceladus formed shortly after the formation of the solar system or that the current activity was triggered by a recent heating event. Under the required conditions, hydrogen production would proceed efficiently, which could provide chemical energy for chemoautotrophic life.
Department of Earth and Planetary Science, University of Tokyo, Bunkyo 113-0033, Japan.
Yasuhito
Y
Sekine
Laboratory of Ocean-Earth Life Evolution Research, Japan Agency for Marine-Earth Science and Technology, Yokosuka 237-0061, Japan.|Research and Development Center for Submarine Resources / Project Team for Next-Generation Technology for Ocean Resources Exploration, Japan Agency for Marine-Earth Science and Technology, Yokosuka 237-0061, Japan.
Takazo
T
Shibuya
Institut für Geowissenschaften, Universität Heidelberg, Heidelberg 69120, Germany.|Institut für Raumfahrtsysteme, Universität Stuttgart, Stuttgart 70569, Germany.
Frank
F
Postberg
Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80303, USA.
Hsiang-Wen
HW
Hsu
Research and Development Center for Submarine Resources / Project Team for Next-Generation Technology for Ocean Resources Exploration, Japan Agency for Marine-Earth Science and Technology, Yokosuka 237-0061, Japan.
Katsuhiko
K
Suzuki
Research and Development Center for Submarine Resources / Project Team for Next-Generation Technology for Ocean Resources Exploration, Japan Agency for Marine-Earth Science and Technology, Yokosuka 237-0061, Japan.
Yuka
Y
Masaki
Department of Solid Earth Geochemistry, Japan Agency for Marine-Earth Science and Technology, Yokosuka 237-0061, Japan.
Tatsu
T
Kuwatani
Department of Natural History Science, Hokkaido University, Sapporo 060-0810, Japan.
Megumi
M
Mori
The University Museum, University of Tokyo, Bunkyo 113-0033, Japan.
Peng K
PK
Hong
Department of Earth and Planetary Science, Tokyo Institute of Technology, Meguro 152-8551, Japan.
Motoko
M
Yoshizaki
Department of Natural History Science, Hokkaido University, Sapporo 060-0810, Japan.
Shogo
S
Tachibana
Graduate School of Environmental Science, Nagoya University, Nagoya 464-8601, Japan.
Sin-iti
SI
Sirono