Spinel Lherzolites from Xalapasco de la Joya, San Luis Potosi, SLP, Mexico

George M. Greene and John C. Butler
Monsanto Company, Houston, Texas 77056
Department of Geology, University of Houston, Houston, Texas 77004

Summary: Ejecta associated with the Xalapasco de la Joya maar 33 km northeast of San Luis Potosi, SLP, Mexico, contain a diverse assemblage of nodules of postulated lower-crust/upper-mantle origin. Spinel lherzolites constitute the most abundant group of nodules and display chemical evidence that crystallization or equilibration took place at temperatures and pressures consistent with upper mantle genesis. Estimated equilibration temperatures and pressures range from 825 to 1025 °C and 7 to 19 kb.

Mineralogical Magazine; December 1979 v. 43; no. 328; p. 483-486; DOI: 10.1180/minmag.1979.043.328.07
© 1979, The Mineralogical Society
Mineralogical Society (www.minersoc.org)