Production of isotopic variability in continental basalts by cryptic crustal contamination

Journal Article · Fri Jan 03 04:00:00 EST 1992 · Science (Washington, D.C.); (United States)

DOI:https://doi.org/10.1126/science.255.5040.72· OSTI ID:7235846

Glazner, A F ^[1]; Farmer, G L ^[2]

---

1. Univ. of North Carolina, Chapel Hill (United States)
2. Univ. of Colorado, Boulder (United States)

Regional variations in the Nd, Sr, and Pb isotopic compositions of Neogene basalts from the western US are commonly interpreted to originate in the subcontinental mantle. In southern California, isotopic variability is restricted to lavas that lack mantle-derived xenoliths; xenolith-bearing basalts have uniform isotopic compositions similar to those of ocean-island basalts (OIBs). Combined with available geochemical data, these observations suggest that isotopic variability at these volcanoes results from subtle crustal contamination, locally by mafic crust, of primitive OIB-like magma. Recognition of such cryptic contamination may help to reconcile local discrepancies between tectonic and isotopic views of the subcontinental mantle.

• OSTI ID: 7235846
• Journal Information: Science (Washington, D.C.); (United States), Journal Name: Science (Washington, D.C.); (United States) Vol. 255:5040; ISSN SCIEA; ISSN 0036-8075
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
ALKALINE EARTH METALS
BASALT
CENOZOIC ERA
CHEMICAL ANALYSIS
CHEMISTRY
DATA
ELEMENTS
EXPERIMENTAL DATA
GEOCHEMISTRY
GEOLOGIC AGES
IGNEOUS ROCKS
INFORMATION
ISOTOPE RATIO
LEAD
METALS
MULTI-ELEMENT ANALYSIS
NEODYMIUM
NUMERICAL DATA
RARE EARTHS
ROCKS
STRONTIUM
TECTONICS
TERTIARY PERIOD
VOLCANIC ROCKS
VOLCANOES