92 resultados para lower crust
Resumo:
The granitic massif Capão Bonito is located in the southwest of the State of São Paulo and is associated with Neoproterozoic evolution of Central Mantiqueira Province. Its rocks outcrop along the edge of the Paraná Basin in a body with elongated shape whose major axis has a general NE-SW, covering an area of approximately 110km2. Occurs in intrusive epimetamorphic rocks of Votuverava Formation, Acungui Group and granitic rocks of the Três Córregos Complex and their placement is related to a brittle tectonics of NE-SW direction shear zones. In metasediments, when preserved from deformational features imposed by mylonitic deformation, preserve up textures and mineralogy of contact metamorphism with development of mineral in albite-epidote and hornblende hornfels facies. The Massif Capão Bonito consists of red syenogranites, holo-leucocratic with biotite and rare hornblende, medium to coarse inequigranulars and isotropic lightly mylonitic and / or cataclastic in marginal regions. Commercially are called Vermelho Capão Bonito and for export as Ruby Red Granite. Rocks belonging to the calcium-alkaline high potassium to shoshonitic series or the series subalkaline potassic and metaluminous to peraluminous character. The magmatism is compatible with granite type A, tardi-orogenic to anorogenic of intraplate environment, from the crust material with lower melting emplacement associated with correlated transtensive structure to shear zones in an extensional environment at the end of collisional event of Orogênese Ribeira. Metamorphism occurred in the region in the greenschist facies, low to medium, generating quartzites, phyllites, schists, and calcium-silicate metabasics
Resumo:
Background Low dose combined oral contraceptives (COC) can interfere in bone mass acquisition during adolescence. To evaluate bone mineral density (BMD) and bone mineral content (BMC) in female adolescents taking a standard low-dose (EE 20 µg/Desogestrel 150 µg) combination oral contraceptive (COC) over a one-year period and compare with healthy adolescents from the same age group not taking COCs.Methods A non-randomised parallel control study with one-year follow-up. Sixty-seven adolescents from 12 to 20 years of age, divided into COC users (n = 41) taking 20 µg EE/150 µg Desogestrel and non-user controls (n = 26), were evaluated through bone densitometry examinations at baseline and 12 months later. Comparisons between groups at study start was done through the Mann-Whitney test with significance level fixed at 5% or corresponding p value; comparisons between groups at study start and 12 months later used variations in median percentages for bone mass variables.Results COC users presented low bone mass acquisition in the lumbar spine and BMD and BMC median variations between baseline and at 12 months of 2.07% and +1.57% respectively whereas the control group presented variations of +12.16% and +16.84% for BMD and BMC, respectively, over the same period. The total body BMD and BMC presented similar evolution during the study in both groups. Statistical significance (pConclusion The use of a low COC dose (EE 20 µg/Desogestrel 150 µg) was associated to lower bone mass acquisition in adolescents during the study period.Trial registration: (Register Number):RBR-5 h9b3c