Completion of the ST2B-2 (Subduction Top to Bottom 2) publication project, resulting in a 74-paper Themed Issue in the Geological Society of America journal GEOSPHERE; link)
Highlights:
Lead article, and cover in GSA Today, advertising the "Subduction Top to Bottom 2" publication project in the GSA journal GEOSPHERE (editors G. E. Bebout, D. W. Scholl, R. J. Stern, L. M. Wallace, and P. Agard; to see this Open Access article, click here)
GEOSPHERE "Subduction Top to Bottom
2" Themed Issue (completed; with 74 papers; click
here)
October 2013 issue of ELEMENTS on
"Nitrogen and its (biogeocosmo)chemical cycling"
(editors
G. E. Bebout, M. L. Fogel, and P. Cartigny; see the
cover of the issue here)
Recent review articles/book chapters
(invited):
Carbon
cycling in subduction zones: Record in HP/UHP metamorphic
rocks, with work based in the Italian/French/Swiss
Alps (collaborative with S. Angiboust, IPGP, Paris;
P. Agard, Université Pierre et
Marie Curie, Paris; Marco Scambellluri and Laura
Crispini, Università
di Genova
[presentations at recent Fall AGU meetings; Goldschmidt
Conference, 2013, 2018; GSA Annual Meeting, 2014; see
Cook-Kollars et al., 2014, and Collins et al., 2015,
both papers in Chemical Geology; Scambelluri et
al., 2016, Earth
and Planetary Science Letters; Jaeckel et al.,
2018, GEOSPHERE;
recent research by EES students Kaylee Kraft (M.S.) and
Gabe Epstein (Ph.D.; see Epstein et al., 2019, LITHOS,
2020, Chemical Geology)]
Volatiles cycling in
subduction zones — Example of the Hikurangi margin,
New Zealand: Ongoing, NSF-funded
research aims to elucidate the cycling of volatiles (C,
N, noble gases) across the Hikurangi margin, North
Island, NZ. This study involves collaborations with
researchers at the GNS Science (New Zealand; Bruce
Christenson), the University of Tokyo (Hirochika
Sumino), and the University of Minnesota (Ikuko Wada).
Subduction inputs at this margin are being evaluated
based in part on analyses of the C and N concentrations
and isotope compositions in the sediment section
entering the Hikurangi trench, using samples recently
recovered by IODP Expedition 375. Thermal models of the
margin will be merged with thermodynamic calculations of
devolatilization in the subducting lithosphere/sediment
section and outputs will be evaluated through analyses
of volcanic and forearc cold seep gases (see Epstein et
al., 2021, G-cubed; click
here).
Nitrogen Isotope (GeoBio)chemistry:
Incorporation of N
during biotic/abiotic chemical alteration of seafloor
basalts and basaltic glasses (collaborative
with Eizo Nakamura, Katsura Kobayashi, Tsutomu Ota, and
Tak Kunihiro, IPM; Open Access article in Astrobiology;
click
here; additional articles in International
Journal of Astrobiology (Anderson et al., 2018), JGR-Planets
(Nikitczuk et al., 2022; click
here), and Astrobiology (Nikitczuk
et al., 2022; click
here)
Other recent research:
We analyzed C-N concentrations and isotopic
compositions of sediment [and
altered seafloor basalt] recovered on ODP Legs 185 and 205 [see
Sadofsky and Bebout,
2004, G-cubed;
Li and Bebout, 2005, JGR and ODP Leg 205 Scientific
Results),
with the goals of characterizing organic sources and
diagenetic history and subduction input fluxes in the
Izu-Bonin-Mariana and Central American convergent
margins. We also have been
working on sediment C-N inputs into the Sunda-Java
margin (see House et al., 2019,
GEOLOGY). Locations for
DSDP/ODP Sites 211, 261, 262, and 765 are shown on the
seafloor topographic map above (image above is from
Smith and Sandwell Global Seafloor Topography, NOAA
and Scripps Institution of Oceanography). Our most recent
shorebased-scientist involvement is for the 2018
drilling at the Hikurangi margin, New Zealand (IODP
Expedition 375).
Records of biogeochemical cycling of N (and other elements) in altered volcanic glasses (collaborative with Eizo Nakamura, Katsura Kobayashi, Tsutomu Ota, and Tak Kunihiro, IPM, Okayama University; recent work by Ph.D. student Matthew Nikitczuk; initial Open Access articles in Astrobiology; click here and Journal of Geophysical Research-Planets; click here)
Most of the research described here is funded by the National Science Foundation — funding for the research at the Institute for Planetary Materials is provided by MEXT (Ministry of Education, Culture, Sports, Science and Technology) and Okayama University, Japan.
_________________________________________________________________________
