摘要
Massif anorthosites form when basaltic magma differentiates in crustal magma chambers to form lowdensity plagioclase and a residual liquid whose density was greater than that of enclosing crustal rocks. The plagioclase and minor pyroxene crystallized in-situ on the floor of the magma chamber to produce the anorthosite complex,and the residual liquid migrated downwards,eventually to solidify as dense Fe-rich cumulates some of which were removed to the mantle.These movements were facilitated by high temperatures in Proterozoic continental crust,thus explaining the restriction of large anorthosite massifs to this period in Earth history.
Massif anorthosites form when basaltic magma differentiates in crustal magma chambers to form lowdensity plagioclase and a residual liquid whose density was greater than that of enclosing crustal rocks. The plagioclase and minor pyroxene crystallized in-situ on the floor of the magma chamber to produce the anorthosite complex,and the residual liquid migrated downwards,eventually to solidify as dense Fe-rich cumulates some of which were removed to the mantle.These movements were facilitated by high temperatures in Proterozoic continental crust,thus explaining the restriction of large anorthosite massifs to this period in Earth history.
基金
supported by the M&Ms project of the French Agence Nationale de Recherche
