TY - JOUR
T1 - Basalt derived from highly refractory mantle sources during early Izu-Bonin-Mariana arc development
AU - Li, He
AU - Arculus, Richard J.
AU - Ishizuka, Osamu
AU - Hickey-Vargas, Rosemary
AU - Yogodzinski, Gene M.
AU - McCarthy, Anders
AU - Kusano, Yuki
AU - Brandl, Philipp A.
AU - Savov, Ivan P.
AU - Tepley, Frank J.
AU - Sun, Weidong
N1 - Publisher Copyright:
© 2021, The Author(s).
PY - 2021/12/1
Y1 - 2021/12/1
N2 - The magmatic character of early subduction zone and arc development is unlike mature systems. Low-Ti-K tholeiitic basalts and boninites dominate the early Izu-Bonin-Mariana (IBM) system. Basalts recovered from the Amami Sankaku Basin (ASB), underlying and located west of the IBM’s oldest remnant arc, erupted at ~49 Ma. This was 3 million years after subduction inception (51-52 Ma) represented by forearc basalt (FAB), at the tipping point between FAB-boninite and typical arc magmatism. We show ASB basalts are low-Ti-K, aluminous spinel-bearing tholeiites, distinct compared to mid-ocean ridge (MOR), backarc basin, island arc or ocean island basalts. Their upper mantle source was hot, reduced, refractory peridotite, indicating prior melt extraction. ASB basalts transferred rapidly from pressures (~0.7-2 GPa) at the plagioclase-spinel peridotite facies boundary to the surface. Vestiges of a polybaric-polythermal mineralogy are preserved in this basalt, and were not obliterated during persistent recharge-mix-tap-fractionate regimes typical of MOR or mature arcs.
AB - The magmatic character of early subduction zone and arc development is unlike mature systems. Low-Ti-K tholeiitic basalts and boninites dominate the early Izu-Bonin-Mariana (IBM) system. Basalts recovered from the Amami Sankaku Basin (ASB), underlying and located west of the IBM’s oldest remnant arc, erupted at ~49 Ma. This was 3 million years after subduction inception (51-52 Ma) represented by forearc basalt (FAB), at the tipping point between FAB-boninite and typical arc magmatism. We show ASB basalts are low-Ti-K, aluminous spinel-bearing tholeiites, distinct compared to mid-ocean ridge (MOR), backarc basin, island arc or ocean island basalts. Their upper mantle source was hot, reduced, refractory peridotite, indicating prior melt extraction. ASB basalts transferred rapidly from pressures (~0.7-2 GPa) at the plagioclase-spinel peridotite facies boundary to the surface. Vestiges of a polybaric-polythermal mineralogy are preserved in this basalt, and were not obliterated during persistent recharge-mix-tap-fractionate regimes typical of MOR or mature arcs.
UR - http://www.scopus.com/inward/record.url?scp=85102851393&partnerID=8YFLogxK
U2 - 10.1038/s41467-021-21980-0
DO - 10.1038/s41467-021-21980-0
M3 - Article
SN - 2041-1723
VL - 12
JO - Nature Communications
JF - Nature Communications
IS - 1
M1 - 1723
ER -