ABSTRACT
Brittle deformation can saturate the Earth's crust with faults and fractures in an apparently chaotic fashion. The details of brittle deformational histories and implications on, for example, seismotectonics and landscape, can thus be difficult to untangle. Fortunately, brittle faults archive subtle details of the stress and physical/chemical conditions at the time of initial strain localization and eventual subsequent slip(s). Hence, reading those archives offers the possibility to deconvolute protracted brittle deformation. Here we report K-Ar isotopic dating of synkinematic/authigenic illite coupled with structural analysis to illustrate an innovative approach to the high-resolution deconvolution of brittle faulting and fluid-driven alteration of a reactivated fault in western Norway. Permian extension preceded coaxial reactivation in the Jurassic and Early Cretaceous fluid-related alteration with pervasive clay authigenesis. This approach represents important progress towards time-constrained structural models, where illite characterization and K-Ar analysis are a fundamental tool to date faulting and alteration in crystalline rocks.
ABSTRACT
The authors report about the possibilities to evaluate correct and early diagnosis by ultrasonographic technique in congenital infant hip dysplasia. The authors report the data concerning 4666 infant hips studied by clinical and ultrasonographic examinations during the years 1990-1991. The cases have been divided according to the age of patients into three groups in the first group, infants less than 1 month old in the II group, infants one to 3 month old; and in the III group, infants 3 month old and over. The use of subdivisions according to age allows higher statistical incidence of dysplasia and immature hip. The newborns and infants included in this study were at their I ultrasonographic examination, had not an instrumental diagnosis of dysplasia, and were not orthopaedic treatment. Treatment with different types of retractors were made in patients with ultrasonographic diagnosis of dysplasia or immature hip, according to the type of dysplasia and age of patient. It has been observed, according to attendance, in the I group of age an high incidence of immature hip (38.03% versus 13.01% in II group and 2.18% in third group) and dysplasia (2.81% versus 0.07% in II group and 0.13% in III group of children). Ultrasonography is replacing conventional radiography as primary method for the diagnosis is of hip dysplasia and thereby, the evaluation of its treatment. The ultrasonography techniques, being harmless for the patient, simple to perform, non-invasive, and economical, make then attractive early diagnostic tools for screening infant congenital hip dysplasia. With early diagnosis, it is possible to begin immediate treatment of congenital dysplasia, resulting a quick resolution of pathological hip disorders. To achieve these results, it is necessary that the orthopaedic surgeon conducts an ultrasonographic examination.
