Banca de QUALIFICAÇÃO: DALTON DA SILVA PINHEIRO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : DALTON DA SILVA PINHEIRO
DATE: 11/11/2021
TIME: 14:00
LOCAL: videoconferência https://www.youtube.com/channel/UCCBwJxTIfyeGmQSqDLK6duw
TITLE:

Distribution patterns of rare-earth elements and Sm-Nd analyses in ediacaran to cambrian magmatic suites in the northeastern Borborema Province, NE Brazil

KEY WORDS:

rare-earth elements; shape coefficients; Sm-Nd isotopes

PAGES: 48
BIG AREA: Ciências Exatas e da Terra
AREA: Geociências
SUMMARY:

The Ediacaran to Cambrian magmatism from Rio Piranhas-Seridó and São José do Campestre Domain, Northeastern portion of Borborema Province, is represented by six suites defined by chemical, mineralogical and petrographic criteria, these are the Shoshonitic, Porphyritic high K calc-alkaline, Equigranular high K calc-alkaline, Calc-alkaline, Alkaline and Chanockitic alkaline suite. This work presents as its main objective the study of rare earth element pattern using a new methodology for application of the patterns in petrogenetic
problems using the suites as a sample universe, making use of the lambda method to obtain the shape coefficients (i.e. λ0, λ1, λ2, λ3). The average values, for the shape coefficients (notation λ0/λ1/λ2/λ3) observed are for shoshonitic (5,36/8,68/108,65/-1438,32), Porphyritic high K calc-alkaline (5,34/11,83/141,35/-1464,81), Equigranular high K calc-alkaline (5,43/9,29/152,15/-1486,88), Calc-alkaline (4,77/5,44/149,65/-1383,71), Alkaline (4,71/3,80/163,69/-1226,27) and Chanockitic alkaline (5,60/9,98/128,10/-1638,25). The results points to strong influence of feldspar fractionation on observed REE pattern mainly with regard to Eu anomalies using λ0 as a fractionation indicator. Some other minerals as garnets, Cpx and Opx could presents influence over λ1 low values, and λ3 high values, while mineral witch alkalis partition influence λ2 high values. The Sm-Nd results pointing to εNd negative values, evidencing an enriched source. The TDM model ages pointing variation between paleoproterozoic (sthaterian) and mesoarchean, witch evidences a source possible age for these rocks. Futhermore, the interpretation is that the shoshonitic suite has the enriched mantle as source associated with a subduction zone related to Transamazonic/Eburnean event (ca. 2,15 Ga), while the rocks from the other suites has as source the continental crust related to gnaissic-migmatitic basement.

BANKING MEMBERS:
Externa à Instituição - ANELISE LOSANGELA BERTOTTI - UFPE
Externo à Instituição - ELTON LUIZ DANTAS - UnB
Presidente - 1513243 - MARCOS ANTONIO LEITE DO NASCIMENTO