Subduction control on the curie isotherm around the Pacific-North America plate boundary in northwestern Mexico (Gulf of California). Preliminary results
Por:
Campos-Enriquez, J. O., Espinosa-Cardena, J. M., Oksum, E.
Publicada:
15 abr 2019
Resumen:
Spectral analysis of NAMAG magnetic data enabled us to estimate depths
to the Curie isotherm along the Pacific-North America plate boundary.
The estimated depths for the Gulf of California, and southern Baja
California peninsula, correlate quite well with the depths to the Moho
available from previous studies based on receiver function, and seismic
refraction. In northernmost Baja California, and southwestern USA no
correlation is observed between depths to the Curie isotherm and depths
to the mantle obtained from receiver function analysis. Depths to the
Curie isotherm are shallower. Along the coastal plains of Sonora and
Sinaloa, differences between receiver function based Mantle depths and
Curie depths are equally large. However, there is more consistency with
depths established by seismic refraction studies. Four zones with
shallow Curie isotherm are identified in southern Gulf of California
(GS1, GS2, GS3, and GS4). GS1 is located at the Gulf of California
mouth. The Alarcon rise is located between GS1 and GS2. Pescaderos Basin
is located northwest of GS2. GS3 stretches from the Carmen Basin to the
Farallon Basin. GS4 extends from Tiburon Island up to northern Guaymas
Basin. Northernmost shallow Curie depth zone (GN1) comprises Upper and
Lower Delfin Basins, as well as the Consag and Wagner Basins. A northern
prolongation also covers Pinacate Volcanic center. The southern shallow
Curie isotherm zones are associated with lithospheric-asthenospheric
material upwelling zones. GN1 also includes a convective component
related to the younger magmatism of the Pinacate Volcanic Field.
Deeper Curie depths are found at southern Baja California peninsula,
interpreted as associated with thicker continental or stretched crust.
It is possible that the crust is underlain or underplated by magnetic
oceanic crust as suggested by satellite magnetic anomalies centered at
the Magdalena shelf. A contrasting pattern features northern Baja
California: deep Curie zones to the west contrasting with relative
shallower Curie isotherm areas to the east. The prolongation towards the
peninsula of the extinct Shirley transform fracture zone roughly
separates the two domains observed along the peninsula, and suggests
that the Curie isotherm along the peninsula is controlled by differences
subduction of the Guadalupe and Magdalena microplates. Major differences
pointed out between northern and southern Gulf of California might
indicate that subduction also played a key role at the beginning of the
opening of the Gulf of California, however, currently, the Curie pattern
is controlled by the rifting processes (shallow Curie zones correlating
quite well with the rift basins and the lithosphere-asthenosphere up
welling material). (C) 2019 The Authors. Published by Elsevier B.V.
Filiaciones:
Campos-Enriquez, J. O.:
Instituto de Geofísica, Universidad Nacional Autónoma de México, Mexico, D.F., Mexico
Univ Nacl Autonoma Mexico, Inst Geofis, Mexico City, DF, Mexico
Espinosa-Cardena, J. M.:
Centro de Investigación Científica y de Educación Superior de EnsenadaBaja California, Mexico
Ctr Invest Cient & Educ Super Ensenada, Ensenada, Baja California, Mexico
Oksum, E.:
Süleyman Demirel University, Engineering Faculty, Department Geophysical Engineering, Isparta, Turkey
Suleyman Demirel Univ, Engn Fac, Dept Geophys Engn, Isparta, Turkey
|