Comparativo study of six granitoid complexes associated with transcurrent faults in the State of São Paulo, Brazil, concerning their architecture and magmatic cycles is presented. Three of these complexes are calc-alkaline (Itaqui, São Roque, Cantareira) and the other three are rapakivi ones (São Francisco, Sorocaba, Itu). The architecture of the complexes is the result of the coalition of severa! magmatic phases with the following temporal emplacement sequence: 1. Early Phase; 2. Main Phase; 3. Early Lateral Accretionary Phase; 4. Phase of Stocks and Circular Intrusions; 5. Final Lateral Accretionary Phase. Also the magmatic units whiçh built up the complexes belong to at least two magmatic cycles with or without an intra-cycle mafic dike phase. The recurrence of the architecture style and the presence of successive magmatic cycles in ali complexes independently of their serial character is discussed in terms of magma emplacement mechanisms, the presence of collecting magma chambers successively tapped and recharged and the reactivation-phases of the transcurrent faults to which the complexes are associated.

EVOLUTION OFIGNEOUS UNITS OF ITAQUI GRANITOID COMPLEX (LATE PRE-CAMBRIAN), STATE OF SÃO PAULO, BRAZIL: GEOLOGICAL, PETROGRAPHIC AND GEOCHEMICAL (MAJOR ELEMENTS) ASPECTS. Chemical data from the 10 magmatic units which build up the calcalkaline granodiorite/monzogranitic Itaqui complex (State of São Paulo, SE Brazil) are discussed. The late Precambrian granitoid is intrusive in the low grade metamorphic São Roque Group, but extensive contacts are done by the expressive Taxaquara transcurrent fault. The chemical data combined with mineralogical and textural ones as well as with the intrusion sequence of the magmatic units allowed the definition of two main magmatic cycles each subdivided in two subcycles. The cycles are separated by a phase of intrusion of melaquartzmonzonite dikes and the younger cycle is followed by the emplacement of tourmaline-muscovite monzogranitic aplites possibly related to the older cycle. Each cycle/subcycle hás its own magmatic evolution trend defïned by several cationic diagrams and involving the fractionatíon of mafic (hornblende/biotite), plagioclase and accessory minerais by different mechanisms.

Resumo A produção de saibro (material argilo-arenoso) em Ubatuba, município do Litoral Norte do Estado de São Paulo, desempenhou papel importante no desenvolvimento municipal, por seu uso na infra-estrutura civil e na manutenção da rede viária. Por ser um bem mineral abundante e não requerer tecnologias sofisticadas para sua produção, seu aproveitamento, ao longo das últimas quatro décadas, deu-se de uma forma desordenada e sem compromisso com a correta finalização da lavra e recuperação ambiental. O trabalho apresenta a definição de quatro indicadores da degradação ambiental devido à extração mineral de saibro e secundariamente rocha ornamental (processos erosivos, irregularidade do terreno, solo exposto e cobertura vegetal) e sua quantificação, obtendo-se um índice numérico de degradação.