%0 Journal Article %T Calc-alkaline magmatism at the ArcheanProterozoic transition: The caico complex basement (NE Brazil) %+ Laboratoire Magmas et Volcans (LMV) %+ Géosciences Rennes (GR) %A Souza De, Z.S. %A Martin, Hervé %A Peucat, Jean-Jacques %A Ferraz Jardim de Sa, Emanuel %A Freitas Macedo De, M.H. %< avec comité de lecture %Z PL01845 %@ 0022-3530 %J Journal of Petrology %I Oxford University Press (OUP) %V 48 %N 11 %P 2149-2185 %8 2007 %D 2007 %R 10.1093/petrology/egm055 %K : calc-alkaline %K magmatism %K NE Brazil %K Paleoproterozoic %K petrogenesis %Z Sciences of the Universe [physics]/Earth Sciences/Petrography %Z Sciences of the Universe [physics]/Earth Sciences/GeochemistryJournal articles %X The Paleoproterozoic metaplutonic rocks of the Caico* Complex Basement (Serido* region, NE Brazil) provide important and crucial insights into the petrogenetic processes governing crustal growth and may potentially be a proxy for understanding the Archean^ Proterozoic transition. These rocks consist of high-K calc-alkaline diorite to granite, with Rb^Sr, U^Pb, Pb^Pb and Sm^Nd ages of c. 225^215 Ga. They are metaluminous, with high YbN, K2O/Na2Oand Rb/Sr, low ISr ratios, and are large ion lithophile elements (LILE) enriched. Petrographic and geochemical data demonstrate that they belong to differentiated series that evolved by low-pressure fractionation, thus resulting in granodioritic liquids.We propose a model in which the petrogenesis of the Caico* Complex orthogneisses begins with partial melting of a metasomatically enriched spinel- to garnet-bearing lherzolite (with high-silica adakite melt as the metasomatic agent), generating a basic magma that subsequently evolved at depth through fractional crystallization of olivine, followed by low-pressure intracrustal fractionation. A subduction zone setting is proposed for this magmatism, to account for both negative anomalies in high field strength elements (HFSE) and LILE enrichment. Mantle-derived juvenile magmatism with the same age is also known in the SaÐ o Francisco andWest Africa cratons, as well as in French Guyana, and thus the Archean^Proterozoic transition marks a very important continental accretion event. It also represents a transition from slab-dominated (in the Archean) to wedge-dominated post-Archean magmatism. %G English %L insu-00197194 %U https://insu.hal.science/insu-00197194 %~ UNIV-ST-ETIENNE %~ INSU %~ UNIV-RENNES1 %~ PRES_CLERMONT %~ CNRS %~ UNIV-BPCLERMONT %~ GR %~ LMV %~ OSUR %~ GIP-BE %~ UR1-HAL %~ UR1-SDLM %~ UR1-SDLMJONCH %~ OPGC %~ TEST-UNIV-RENNES %~ TEST-UR-CSS %~ UNIV-RENNES %~ UDL %~ UR1-ENV