TY - JOUR
T1 - Unraveling short-lived rejuvenated volcanism and a rapid transition from shield stage at O'Higgins Guyot, Juan Fernández Ridge, Pacific SE
AU - Lara, Luis E.
AU - Díaz-Naveas, Juan
AU - Reyes, Javier
AU - Jicha, Brian
AU - Orozco, Gabriel
AU - Tassara, Andrés
AU - Kay, Suzanne
N1 - Publisher Copyright:
© 2018 Elsevier Ltd
PY - 2018/11
Y1 - 2018/11
N2 - Rejuvenated volcanism is a common and usually low volume stage in the archetypical evolution of oceanic islands. Magmas related to this transient stage are mostly alkaline with a more depleted source than the mantle plume that fed the shield stage. Being ubiquitous in oceanic islands, only a few rock samples with geochemical features of post-erosional volcanism have been recovered from seamounts worldwide, although usually with a great uncertainty about the eruptive age and the stratigraphic framework. Here we report on the finding of a young, subaqueous lava flow with a fresh morphology as shown in high-resolution bathymetry, just on top of the O'Higgins Guyot, Juan Fernández Ridge in the SE Pacific. Basanite rocks recovered are quite similar to other post-erosional lavas recognized along the Juan Fernández Ridge, and were dated at ca. 8.2 Ma, only slightly younger than the youngest, shield stage section of the 8.5–9.3 Ma guyot. Such a rapid transition calls for a process explaining both the summit erosion of the shield volcano and the subsequent volcanism with a different magma source and/or melting process in a narrow time window. Isostatic rebound and subsequent flexural deformation may have triggered partial melting of the mantle source just below the seamount, with rapid ascent assisted by the same structural conditions but precluded shortly after.
AB - Rejuvenated volcanism is a common and usually low volume stage in the archetypical evolution of oceanic islands. Magmas related to this transient stage are mostly alkaline with a more depleted source than the mantle plume that fed the shield stage. Being ubiquitous in oceanic islands, only a few rock samples with geochemical features of post-erosional volcanism have been recovered from seamounts worldwide, although usually with a great uncertainty about the eruptive age and the stratigraphic framework. Here we report on the finding of a young, subaqueous lava flow with a fresh morphology as shown in high-resolution bathymetry, just on top of the O'Higgins Guyot, Juan Fernández Ridge in the SE Pacific. Basanite rocks recovered are quite similar to other post-erosional lavas recognized along the Juan Fernández Ridge, and were dated at ca. 8.2 Ma, only slightly younger than the youngest, shield stage section of the 8.5–9.3 Ma guyot. Such a rapid transition calls for a process explaining both the summit erosion of the shield volcano and the subsequent volcanism with a different magma source and/or melting process in a narrow time window. Isostatic rebound and subsequent flexural deformation may have triggered partial melting of the mantle source just below the seamount, with rapid ascent assisted by the same structural conditions but precluded shortly after.
UR - http://www.scopus.com/inward/record.url?scp=85053835509&partnerID=8YFLogxK
U2 - 10.1016/j.dsr.2018.08.012
DO - 10.1016/j.dsr.2018.08.012
M3 - Article
AN - SCOPUS:85053835509
SN - 0967-0637
VL - 141
SP - 33
EP - 42
JO - Deep-Sea Research Part I: Oceanographic Research Papers
JF - Deep-Sea Research Part I: Oceanographic Research Papers
ER -