@misc{10481/77171,
year = {2021},
month = {10},
url = {https://hdl.handle.net/10481/77171},
abstract = {Mantle-derived volcanic rocks from the Subbetic hyperextended basin in SE Spain provide new insights into the composition and
mechanical behavior of the mantle during continental rifting. The present study describes a sequential restored cross-section along
with geochemical characteristics of the basaltic rocks interbedded within the Mesozoic succession of the basin. Sedimentary
stacking patterns of minibasins above the mobilized salt reflect the relationships with coeval basaltic volcanism. We recognize
two type localities on the basis of volcanic facies, the presence of shallow intrusive bodies, and age of the associated
sedimentary formations. The first type corresponds to subaqueous pillow-lava flows and subvolcanic sills and dikes associated
with Lower Jurassic marly limestones and Middle Jurassic oolitic limestones. The Jurassic basalts present enriched MORB
compositions with moderate La/Sm and low Sm/Yb ratios. Interestingly, a significant group of this Jurassic basaltic magmatism
departs from the typical MORB-OIB array, showing deep Nb-Ta negative anomalies and high Th/Nb ratios. The second type
comprises subaqueous lava flows, also including pillow-shaped basalts interlayered with hyaloclastite deposits and Upper
Cretaceous clays, radiolarites, and marly limestones. The Cretaceous magmatism is characterized by highly enriched MORB
compositions. Furthermore, the moderate Sm/Yb values and the positive correlation between LREE/HREE and Zr point to the
involvement of deep (Grt-present) mantle sources in the origin of the Cretaceous basaltic melts. We interpret the Lower-
Middle Jurassic calc-alkaline signal as due to the partial melting of recycled crustal rocks within the upper mantle, i.e.,
associated with remnants of pre-Mesozoic subducted slabs. These characteristics are similar to those described in Triassic
basaltic rocks widespread throughout the External Zone of the Betic Cordillera. Mantle-derived basalts interlayered within the
Lower Jurassic syn-rift deposits indicate that melting and deformation within the lithospheric mantle was initiated early during
continental rifting. Accordingly, we suggest that Early to Middle Jurassic mantle melts promoted failure within the upper
mantle, thus contributing to the inception of lithospheric-scale shear zones, which, in turn, controlled the evolution of this
magma-poor hyperextended margin. Subsequently, rift evolution gave way to the activation of deeper melt sources in the
mantle and an increase of the alkaline signature at the Cretaceous time.},
organization = {Spanish Geological Survey},
organization = {Junta de Andalucia	A-RNM-005-UGR18	
PY20-01387},
organization = {Spanish Government	REViSE-Betics-PID2020-119651RB-I00},
publisher = {GeoScience World},
title = {Submarine Basaltic Magmatism in the Subbetic Basin (Southern Spain): Insights into Melt-Weakening Processes during Mesozoic Continental Rifting},
doi = {10.2113/2021/5505884},
author = {Díaz Alvarado, Juan and Azor Pérez, Antonio},
}