8 resultados para Chatham Rise
em University of Queensland eSpace - Australia
Resumo:
Cretaceous-Tertiaty (K-T) boundary (ca. 65 Ma) sections on a Southwest Pacific island containing dinosaurs were unknown until March 2003 when theropod bones were recovered from the Takatika Grit on the remote Chatham Islands (latitude 44 degrees S, longitude 176 degrees W), along the Chatham Rise. Tectonic and palaeontologic evidence support the eastward extension of a ca. 900 km land bridge that connected the islands to what is now New Zealand prior to the K-T boundary. The Chathams terrestrial fauna inhabited coastal, temperate environments along a low-lying, narrow, crustal extension of the New Zealand subcontinent, characterised by a tectonically dynamic, volcanic landscape with eroding hills (horsts) adjacent to flood plains and deltas, all sediments accumulating in grabens. This finger-like tract was blanketed with a conifer and clubmoss (Lycopodiopsida) dominated forest. The Chatham Islands region would have, along with New Zealand, provided a dinosaur island sanctuary after separating from the Gondwana margin ca. 80 Ma. (c) 2005 Elsevier B.V. All rights reserved.
Resumo:
Capillary rise in porous media is frequently modeled using the Washburn equation. Recent accurate measurements of advancing fronts clearly illustrate its failure to describe the phenomenon in the long term. The observed underprediction of the position of the front is due to the neglect of dynamic saturation gradients implicit in the formulation of the Washburn equation. We consider an approximate solution of the governing macroscopic equation, which retains these gradients, and derive new analytical formulae for the position of the advancing front, its speed of propagation, and the cumulative uptake. The new solution properly describes the capillary rise in the long term, while the Washburn equation may be recovered as a special case. (C) 2004 Elsevier Inc. All rights reserved.
Resumo:
Peter Brown, perhaps the world's leading scholar in the field of late antiquity, has produced a substantially revised and expanded edition of one of his major books, drawing on the vast volume of recent work. This essay summarizes its central arguments, especially the significance it attributes to developments away from the Mediterranean and to the seventh century, which together allow the topic to be seen in a compelling new light. It applauds the sustained excellence of Brown's prose, as well as his frame of reference and historical imagination. Some questions are raised concerning his deployment of sources, the importance given to the north, the ability to make decisions that people are credited with, and the coming of Islam. That a scholar of Brown's eminence is able to relish and appropriate effectively work that appeared subsequent to the first edition of this book is a tribute to his stature.