Melilitites: partial melts of the thermal boundary layer?

Autor: Elizabeth Ann Dunworth, Marjorie Wilson, Jeffrey M. Rosenbaum
Rok vydání: 1995
Předmět:
Zdroj: Contributions to Mineralogy and Petrology. 119:181-196
ISSN: 1432-0967
0010-7999
DOI: 10.1007/bf00307280
Popis: Silica-poor, calcium-rich melilitites form a chemical and isotopic end-member of the spectrum of mafic magmas of the Tertiary-Quaternary volcanic province of western and central Europe. We propose that these unusual magmas are derived by partial melting of the thermal boundary layer (TBL) at the base of the European lithosphere. The processes involved in the evolution of the TBL have been constrained using major and trace element and Nd-Sr-Pb isotope data for Tertiary melilitites from the Urach, Hegau, and Rhine graben regions of Germany. The initiation of boundary layer evolution is limited in time by a major phase of Permo-Carboniferous rifting and associated magmatism postdating the Hercynian orogeny which would have destroyed the existing TBL by delamination. Model calculations indicate that the isotopic composition of the melilitite source cannot develop within the TBL over geologically reasonable periods of time (250–300 Million years) if the TBL evolves solely by incorporation of small degree (
Databáze: OpenAIRE
Externí odkaz: