1989/03/01 by Michael Storey, G. Rogers, A.D. Saunders +1 · 3 citations
Earth and Planetary Sciences · Computer Science · #Geological and Geochemical Analysis #Geochemistry and Geologic Mapping #High-pressure geophysics and materials
paper · doi:10.1111/j.1365-3121.1989.tb00352.x
openalex publication_date 1989/03/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/06/23
ABSTRACT The Holocene San Quintín volcanic province in northern Baja California comprises spinel‐lherzolite‐bearing alkali basalts. Trace element (La/Nb = 0.57–0.73; K/Rb = 402–479; La N /Yb N = 8.4, 9.9) and isotopic ratios ( 87 Sr/ 86 r = 0.70323–0.70352; 143 Nd/ 144 Nd = 0.512924–0.512996; 206 Pb/ 204 Pb = 19.108, 19.250; 207 Pb/ 204 Pb = 15.567, 15.589; 208 Pb/ 204 Pb = 38.82, 38.85) show that the lavas are compositionally indistinguishable from some ocean island, plume‐associated basalts such as Hawaii and the Azores, and testify to an asthenospheric source for the magmas. The occurrence in Baja of such lavas may be related to the nature of the cessation of plate subduction beneath the peninsula; at present, San Quintín (and volcanic provinces to the north) are underlain by a ‘no‐slab window', whereas immediately to the south, remanent oceanic lithosphere may be preserved as a relict slab. This may act as a bamer to the upward passage of diapirs or magmas from the asthenosphere.