Harigane Yumiko

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Last Name
Harigane
First Name
Yumiko
ORCID
0000-0002-8133-0700

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  • Article
    Multi-scale magnetic mapping of serpentinite carbonation
    (Nature Publishing Group, 2017-11-30) Tominaga, Masako ; Beinlich, Andreas ; Lima, Eduardo A. ; Tivey, Maurice A. ; Hampton, Brian A. ; Weiss, Benjamin ; Harigane, Yumiko
    Peridotite carbonation represents a critical step within the long-term carbon cycle by sequestering volatile CO2 in solid carbonate. This has been proposed as one potential pathway to mitigate the effects of greenhouse gas release. Most of our current understanding of reaction mechanisms is based on hand specimen and laboratory-scale analyses. Linking laboratory-scale observations to field scale processes remains challenging. Here we present the first geophysical characterization of serpentinite carbonation across scales ranging from km to sub-mm by combining aeromagnetic observations, outcrop- and thin section-scale magnetic mapping. At all scales, magnetic anomalies coherently change across reaction fronts separating assemblages indicative of incipient, intermittent, and final reaction progress. The abundance of magnetic minerals correlates with reaction progress, causing amplitude and wavelength variations in associated magnetic anomalies. This correlation represents a foundation for characterizing the extent and degree of in situ ultramafic rock carbonation in space and time.
  • Article
    Occurrence of felsic rocks in oceanic gabbros from IODP hole U1473A: Implications for evolved melt migration in the lower oceanic crust.
    ( 2018-12-20) Nguyen, Du Khac ; Morishita, Tomoaki ; Soda, Yusuke ; Tamura, Akihiro ; Ghosh, Biswajit ; Harigane, Yumiko ; France, Lydéric ; Liu, Chuanzhou ; Natland, James H. ; Sanfilippo, Alessio ; MacLeod, Christopher J. ; Blum, Peter ; Dick, Henry J. B.
    Felsic rocks are minor in abundance but occur ubiquitously in International Ocean Discovery Program Hole U1473A, Southwest Indian Ridge. The trace element abundances of high-Ti brown amphibole, plagioclase, and zircon in veins, as well as the presence of myrmekitic texture in the studied felsic rocks support crystallization origin from highly-evolved melts, probably controlled by fractional crystallization. Based on geochemical criteria and texture of the mineral assemblage in felsic rocks and their relationship with host gabbros, they can be divided into three types: (1) Felsic rock with sharp boundaries is formed when felsic melt intrudes into fractures of host gabbros, resulting in minimal interaction between the melt and the wall minerals. (2) Replacive felsic rock, which is characterized by a pseudomorphic replacement of minerals in the host gabbro. This vein type is caused by the replacement of the host mineralogy by minerals in equilibrium with the felsic melts. (3) Felsic rock with diffused boundaries is formed either by infiltration of felsic melt into the solidifying gabbro body or crystallization of interstitial melts. Infiltration modes of felsic melts are likely controlled by the temperature condition of the cooling host gabbros.