The Argentine Precordillera (“Precordillera”) is part of a larger terrane which is exotic to the western margin of Gondwana. This larger terrane is characterized by a Grenvillian-type basement and the presence of Laurentian carbonate-platform rocks of Cambrian–Ordovician age. The original position of the terrane is interpreted to be the Ouachita embayment of southeastern Laurentia.

Работа посвящена решению вопроса о современных аналогах нефтеобразующих палеобассейнов. Приведены общие сведения о биоразнообразии современных гипергалинных водоемов. Предпринята попытка отождествления акритарх нефтей и нефтематеринских пород с рецентными галофитами. Установлены особенности продуцирования органических веществ. Рассмотрены основные закономерности литогенеза в аридных зонах и диагенез органических веществ. Показано, что в процессах нефтегазообразования бактериальные процессы и экзотермическая деструкция концентрированных органических веществ имеют столь же важное значение, что и глубинный тепловой поток. На основании синхронности накопления эвапоритовых осадков и появления пресноводных видов приводятся зоогеографические признаки районов нефтеобразования. Указывается на перспективную нефтегазоносность шельфа Аргентины, юга и севера Бразилии, залива Карпентария (Австралия), Японского, Кораллового и Тасманова морей.

Книга предназначена для специалистов в области нефтяной геологии, геохимиков, палеонтологов, биологов, зоогеографов

The deformation mechanisms and controls that operate in the mylonite/ultramylonite transition are interpreted from microstructural observation. The investigated mylonites and ultramylonites were derived from a granitic protolith which was deformed under greenschist facies conditions, and in the presence of fluid, in a regional-scale shear zone from northwest Argentina. Several deformation mechanisms were recognized to operate simultaneously in different domains of the microstructure at each particular stage of the microstructural evolution. This continuously mobile deformation partitioning, present throughout the microstructural evolution, ceases abruptly in the ultramylonite stage, where a stable-state microstructure is achieved. Domainal quartz c-axis fabrics indicate that quartz deforms by crystal-plastic processes at the initial and intermediate stages of deformation, but solution-transfer processes become predominant in the ultramylonite stage. Plagio-clase is progressively transformed into muscovite through retrograde softening reactions. K-feldspar is progressively transformed into fine-grade aggregates via cataclastic flow and incipient recrystallization. Mica deforms by kinking and basal slip, with progressive development of fine-grained, morphologically oriented aggregates. Plagioclase disappearance as well as the development of intrafolial microfolds characterize the transition between the mylonitic and ultramylonitic domains. Disruption of these microfolds is interpreted to represent the ultimate control on the localization of the ultramylonite bands, с 1998 Elsevier Science Ltd. All rights reserved

The Bajo de la Alumbrera porphyry copper-gold deposit is located within the northern Sierras Pampeanas in the eastern Andes Mountains of northwestern Argentina. It formed in a tectonically favourable location within a major arc-oblique wrench fault system, the Tucuman Transfer Zone. Initial andesitic volcanism deposited on crystalline Lower Palaeozoic basement, and subsequently emplaced dacitic subvolcanic stocks are directly related to eastward subduction of the Nazca oceanic plate beneath the western continental margin of South America. Structural preparation and shallowing of the angle of subduction of the Nazca plate -related to the arc-normal Juan Fernandez Ridge on that plate - probably aided the ascent of calc-alkaline oceanic arc-related magma into the Tucuman Transfer Zone.

Геология перспективных месторождений Арисаро и Линдеро, провинция Сальта, Северо-запад Аргентины: гидротермальная железисто-медно-золотая минерализация среднего миоцена

The Arizaro and Lindero prospects are possibly the youngest recognised examples of the hydrothermal iron oxide-copper-gold class of deposits in the world. These two prospects, and numerous other iron-oxide manifestations, form a newly discovered district within northwest Argentina. The Arizaro and Lindero prospects are hosted within mid-Miocene, calc-alkaline, dominantly andesitic, volcanic complexes that formed within a convergent plate margin tectonic setting. This descriptive paper presents observations from surface geology and petrographic studies.