Plains volcanism in Tharsis region on Mars: Ages and Rheology of Eruption Products Remote sensing data show clusters of low shield volcanoes in Tharsis volcanic province on Mars (Hauber et al., 2009). These low shield volcanoes and associated landforms are comparable with terrestrial plain-style volcanic products (Plescia, 1981) as defined by Greeley (1982) in the Snake River Plain in Idaho, which represents an intermediate style of volcanic activity ranging between flood basalts and the Hawaiian shields. While a number of recent studies addressed some aspects of low shield volcanoes, in particular their morphology, morphometry, and lava rheology, no systematic study including the chronology for the entire region of Tharsis is available so far. The goal of this work is to determine relative and absolute ages of low shield volcanoes and surrounding lava flows and their basic rheological properties. We used crater size-frequency distribution method (CSFD) developed by Hartman and Neukum (2001) and Ivanov (2001) for determination of absolute dating of the surface. For calculation of the rheological properties of the lava, we used methods established by Hiesinger et al. (2007). It is known that the low shield volcanoes on Mars consist of basaltic lavas that had low viscosities during their effusion, which can...

Made available in DSpace on 2014-12-17T15:12:18Z (GMT). No. of bitstreams: 1 AureliaSA.pdf: 467613 bytes, checksum: acef70f5b973d0f5f78b5c8c1dda5051 (MD5) Previous issue date: 2005-12-06 / Aristotle's definition of tragedy indicates a metaphysical project insinuated by a notion of k?tharsis. The reconstruction of Aristotle's method of definition is inspired in the concepts of en?rgeia and d?namis taken from Physics, understanding cause as substance. The Doctrine of the Four Causes is the theoretical basis of the definition of tragedy, placing tragedy in the genre of imitation and distinguishing its species: language (material cause), noble and complete action (formal cause), actors (efficient cause) and k?tharsis (temporarily identified with the final cause). Nevertheless, there is no final cause in the definition of tragedy. The k?tharsis of passions is experienced by the spectator when he witnesses tragedy, which is the imitation of a noble action, executed by actors and not narrated. Aristotle justifies hid proposition in favor of mimesis by assuming that imitation is natural to man since infancy and the view of objects allows whoever contemplates them to identify and learn the originals. As a metaphysical principle, k?tharsis is projected to beyond definition of tragedy, where it is manifested cathartically, in the spectator. Research about the spectator brings one back to the definition of tragedy, where the imitation is an imperfect copy which evokes in the spectator the presence of the originals of the imitated sentiments, thus realizing the k?tharsis of these emotions. In this way k?tharsis reveals itself as selfknowledge and approach of divine truth and perfections. / A defini??o de trag?dia na Po?tica aponta para um projeto metaf?sico insinuado pela no??o de k?tharsis. A reconstitui??o do m?todo de defini??o de Arist?teles inspira-se nos conceitos de en?rgeia e d?namis retirados da F?sica, entendendo causa como subst?ncia. A Doutrina das Quatro Causas ? o referencial te?rico que orienta a defini??o de trag?dia, enquadrando-a no g?nero da imita??o e dividindo-lhes as esp?cies: linguagem (causa material), a??o nobre e completa (causa formal), atores (causa eficiente) e k?tharsis (temporariamente identificada como causa final). Entretanto, n?o h? causa final na defini??o de trag?dia. A k?tharsis das paix?es processa-se no espectador ao assistir ? trag?dia que ? a imita??o de uma a??o nobre, executada pelos atores e n?o narrada. Arist?teles justificou sua proposi??o em favor da m?mese ao assumir que "imitar ? natural ao homem desde a inf?ncia e a vista das imagens proporciona a quem as contempla aprender e identificar cada original". Como princ?pio metaf?sico, K?tharsis se projeta para fora da defini??o de trag?dia, onde realiza-se a manifesta??o cat?rtica, no espectador. A pesquisa em torno do espectador retorna para a defini??o de trag?dia, onde a imita??o ? c?pia imperfeita que evoca no espectador a presen?a dos originais daqueles sentimentos imitados, realizando assim, a k?tharsis dessas emo??es. K?tharsis revela-se ent?o, como auto-conhecimento e aproxima??o das verdades e perfei??es divinas / 2020-01-01