Abstract

Determination of the rate of emplacement of batholiths is complicated by the complexity of a process involving segregation, intrusion and congelation, and by a lack of knowledge of the nature of granite magma. Times of uprise and freezing of individual pulses are of the order of a million years, possibly much longer for segration; rates which are similar to that of sea floor spreading. The construction of a composite batholith takes some 50–70 m.y. and although distinct episodes may be recognized locally it is likely to be, overall, a sensibly continuous process for a single, linear, consanguineous batholith such as that of coastal Peru.