stripes
This volcanic province, lying along the coast just to the south of Recife, includes flows, dykes and tuffs of rhyolitic, including comenditic, trachytic, andesitic and basaltic composition. A riebeckite granite of about 3 km2 forms the Cape of Santo Agostinho itself (see geological map in Cobra, 1971). Rock analyses, including REE, are given by Sial et al. (1980).
COBRA, R.Q. 1971. Geologia da regiao do Cabo de Santo Agostinho, Pernambuco. Boletim Departamento Nacional da Producao Mineral, Divisao de Fomento da Producao Mineral, 142: 1-52
A. N. Sial, personal communication, 1982.
SIAL, A.N., BARBA, G.S., VILLARROEL, H.S. and ALBUQUERQUE, C.A.R. 1980. Geoquimica de elementos terras raras do granito do Cabo de Santo Agostinho, Pernambuco. Anais Congresso Brasileiro de Geologia, 31(4): 2285-99.
Bahia alkaline province (Fig. 195)
The distribution, sizes and forms of this northeast-southwest trending group of intrusions is not well known, and all the published maps vary considerably (e. g. Cordani et al. 1974; Fujimori, 1972, Fig. 1; Oliveira et al. 1980; Pedreira, 1976; Souto, 1972).