Relict mountain slope deposits of northern Portugal: facies,sedimentogenesis and environmental implications

This paper deals with the formation processes and the palaeoenvironmental significance of relict slope deposits located on the uppermost part of the north Portugal mountains. For this purpose, seven key sites representative of the different lithofacies have been selected and analysed in detail. The data show that three main dynamic processes are responsible for the emplacement of regional fossil slope deposits: runoff, debris flows and dry grain flows. The ubiquity of these processes and the lack of frost‐related features or landforms do not support the existence of severe Pleistocene climates in this part of the lberian Peninsula as postulated by previous work. Pedological data gathered at one of the study sites show that a subalpine environment was probably present at 700–800 m altitude between 29 and 14 kyr. Using data from the Pyrenees Mountains, a 6.5 to 12°C depression in mean annual temperature has been tentatively postulated for this Pleniglacial period. Copyright © 2003 John Wiley & Sons, Ltd.     

Sedimentogenesis cyclicity, stages, and phases in the development of the Late Silurian-Early Devonian biota in Northeast Asia

It is established that the Pridolian-Eifelian megacycle in Northeast Asia is represented by five macrocyclites. The analysis of fossils in Upper Silurian-Lower Devonian sections of the region reveals ten levels marked by large-scale reorganizations in the composition and structure of the biota in this basin. These levels are united in pairs by five maximums, which are characterized by the highest values of the taxonomic renewal coefficient, coincide with the boundaries of macrocyclites, and are traceable through the entire sedimentation basin.     

EAST ASIA MARGINAL BASINS SEDIMEN-TOGENESIS FEATURES

The alternations of sedimentogenic and asedimentogenic belts on the continental shelf and slope are distinctive features in the East Asia marginal basins.These sedimentogenesis characteristics areconditioned by the terrigenous material supply and their distribution patterns. Facial analysis of the marginal basins reveals a number of typical facial models which are comparablewith the geosynclinal and subplatform formations of the ancient basins. The paragenetical situation and simultaneous coexistence of these facial models in the modern margi-nal seas indicate that the ancient formation could be deposited in the same way,at the same time andeven in the same basin.