TY - JOUR
T1 - A record of spontaneous subduction initiation in the Izu-Bonin-Mariana arc
AU - Arculus, Richard J.
AU - Ishizuka, Osamu
AU - Bogus, Kara A.
AU - Gurnis, Michael
AU - Hickey-Vargas, Rosemary
AU - Aljahdali, Mohammed H.
AU - Bandini-Maeder, Alexandre N.
AU - Barth, Andrew P.
AU - Brandl, Philipp A.
AU - Drab, Laureen
AU - Do Monte Guerra, Rodrigo
AU - Hamada, Morihisa
AU - Jiang, Fuqing
AU - Kanayama, Kyoko
AU - Kender, Sev
AU - Kusano, Yuki
AU - Li, He
AU - Loudin, Lorne C.
AU - Marsaglia, Kathleen M.
AU - McCarthy, Anders
AU - Meffre, Sebastién
AU - Morris, Antony
AU - Neuhaus, Martin
AU - Savov, Ivan P.
AU - Sena, Clara
AU - Tepley, Frank J.
AU - Van Der Land, Cees
AU - Yogodzinski, Gene M.
AU - Zhang, Zhaohui
AU - Maffione, Marco
PY - 2015/9/1
Y1 - 2015/9/1
N2 - The initiation of tectonic plate subduction into the mantle is poorly understood. If subduction is induced by the push of a distant mid-ocean ridge or subducted slab pull, we expect compression and uplift of the overriding plate. In contrast, spontaneous subduction initiation, driven by subsidence of dense lithosphere along faults adjacent to buoyant lithosphere, would result in extension and magmatism. The rock record of subduction initiation is typically obscured by younger deposits, so evaluating these possibilities has proved elusive. Here we analyse the geochemical characteristics of igneous basement rocks and overlying sediments, sampled from the Amami Sankaku Basin in the northwest Philippine Sea. The uppermost basement rocks are areally widespread and supplied via dykes. They are similar in composition and age-as constrained by the biostratigraphy of the overlying sediments-to the 52-48-million-year-old basalts in the adjacent Izu-Bonin-Mariana fore-arc. The geochemical characteristics of the basement lavas indicate that a component of subducted lithosphere was involved in their genesis, and the lavas were derived from mantle source rocks that were more melt-depleted than those tapped at mid-ocean ridges. We propose that the basement lavas formed during the inception of Izu-Bonin-Mariana subduction in a mode consistent with the spontaneous initiation of subduction.
AB - The initiation of tectonic plate subduction into the mantle is poorly understood. If subduction is induced by the push of a distant mid-ocean ridge or subducted slab pull, we expect compression and uplift of the overriding plate. In contrast, spontaneous subduction initiation, driven by subsidence of dense lithosphere along faults adjacent to buoyant lithosphere, would result in extension and magmatism. The rock record of subduction initiation is typically obscured by younger deposits, so evaluating these possibilities has proved elusive. Here we analyse the geochemical characteristics of igneous basement rocks and overlying sediments, sampled from the Amami Sankaku Basin in the northwest Philippine Sea. The uppermost basement rocks are areally widespread and supplied via dykes. They are similar in composition and age-as constrained by the biostratigraphy of the overlying sediments-to the 52-48-million-year-old basalts in the adjacent Izu-Bonin-Mariana fore-arc. The geochemical characteristics of the basement lavas indicate that a component of subducted lithosphere was involved in their genesis, and the lavas were derived from mantle source rocks that were more melt-depleted than those tapped at mid-ocean ridges. We propose that the basement lavas formed during the inception of Izu-Bonin-Mariana subduction in a mode consistent with the spontaneous initiation of subduction.
UR - http://www.scopus.com/inward/record.url?scp=84940545366&partnerID=8YFLogxK
U2 - 10.1038/ngeo2515
DO - 10.1038/ngeo2515
M3 - Article
AN - SCOPUS:84940545366
SN - 1752-0894
VL - 8
SP - 728
EP - 733
JO - Nature Geoscience
JF - Nature Geoscience
IS - 9
ER -