Geologia e geocronologia da Suite Metamorfica Colorado e suas encaixantes, SE de Rondonia: implicacoes para a evolucao Mesoproterozoica do SW do Craton Amazonico

Combined geochronological (U-Pb, Ar/ Ar, and Rb-Sr) geological data help define an important tectonomagmatic event in the Colorado do Oeste and Cabixi regions, southeastern Rondônia, Brazil, and characterize the Colorado Metamorphic Suite (CMS), well represented by rock assemblages which experienced deformation and metamorphic recrystallization (upper-amphibolite facies). The suite is composed of: 1) porphyritic monzogranite associated with amphibolite (bimodal magmatism), 2) interlayered clastic and chemical metasedimentary rocks (sillimanite schists and iron formation), 3) muscovite-garnet leucogranite, and 4) mafic-ultramafic intrusive rocks. The CMS mafic rocks occur as undeformed isolated bodies of layered coarse-grained metagabbro, still preserving typical cumulate igneous texture. U-Pb zircon isotopic data for three fractions of sample RO-10 define a discordia with an upper intercept (crystallization) age of 1352 + 4/-3 Ma (MSWD = 0.18). The porphyritic ortogneisses (RO-15; monzogranite and amphibolite) yielded a Rb-Sr whole rock isochron age of 1360 ± 45 Ma, and Sr/Sr = 0.7040 ± 0.0012 (MSWD = 9.2). One sample of aplite that is subparallel to the main regional foliation has furnished an age of 1360 ± 13 Ma. The Ar/Ar data for muscovite from a anatectic leucogranite (RO-14) yielded plateau ages of 1312 ± 3 Ma (grain 1), and 1303 ± 2 Ma/1305 ± 2 Ma (grain 2). Grain 3 presented an heterogeneous isotopic spectrum, the integrated age being 1289 ± 2 Ma. Hornblende from two amphibolite samples yielded Ar/ Ar plateau ages of 1313 ± 4 Ma; 1313 ± 6 Ma and 1312 ± 3 Ma (RO-18), and 1325 ± 3 Ma; 1326 ± 2 Ma; 1330 ± 3 Ma (RO-19). The weighted-mean age is 1319 ± 10 Ma, and is interpreted as the best estimated age for regional metamorphic cooling. These data suggest that southeastern Rondônia was affected by a tectonomagmatic event at ca. 1.36 - 1.32 Ga, predating the evolution of the Nova Brasilândia Terrane (1215 - 1110 Ma). However, the unequivocal characterization of an orogeny refered to the time interval 1.36 - 1.32 Ga is still uncertain due to scarcity of geochronological data in the region. Similar ages are reported for correlatable intrusive rocks which cut the polydeformed basement rocks of central Rondônia. Thus, these ages are compatible with available Mesoproterozoic tectonic models for the SW Amazonian Craton

Prospective Mediation Models of Sleep, Pain, and Daily Function in Children With Arthritis Using Ecological Momentary Assessment

OBJECTIVES: Sleep is an emerging area of concern in children with juvenile idiopathic arthritis (JIA). Research shows the presence of poor sleep quality and related adverse outcomes in pediatric pain populations, including JIA, but few studies have examined the prospective patterns of association between sleep and associated outcomes. This prospective study evaluated the direction and magnitude of associations between subjective sleep characteristics (sleep quality, difficulty initiating sleep, and sleep duration), pain intensity, and functional limitations in children with JIA. We hypothesized that pain intensity would partially mediate the relationship between sleep and functional limitations. METHODS: Children and adolescents with JIA (n= 59, age range = 8–18) recruited during clinic visits, completed smartphone-based diaries for one month. Subjective sleep characteristics were reported each morning; pain and functioning were assessed three times daily. RESULTS: As hypothesized, the associations between sleep quality and functional limitations and between difficulty initiating sleep and functional limitations were partially mediated by pain intensity, at any given moment (z = −3.27, p = .001, z = 2.40, p < .05). Mediation was not detected in a model testing the association between sleep duration, pain intensity, and functional limitations (z = −.58, p = .56). DISCUSSION: Results suggest that sleep is integral to understanding the momentary association between pain intensity and functioning in children with JIA