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Downcutting and infill of incised valley systems is mostly controlled by relative sea-level changes, and studies on valley-fill successions accumulated independently from relative sea-level or lake-level oscillations are limited. This study focuses on the Plio-Pleistocene evolution of a fluvial drainage system developed in Southern Tuscany (Italy) following a regional marine forced regression at the end of Piacentian. Subsequent in-valley aggradation was not influenced by any relative sea-level rise, and valley morphological and depositional history mainly resulted from interaction between sediment supply and tectonic activity, which caused segmentation of the major valley trunk into localized subsiding depocenters separated by upwarping blocks. Fluvial sedimentation occurred until late Calabrian time, when the major river abandoned that valley, where minor fluvio-lacustrine depocenters allowed accumulation of siliciclastic and carbonate deposits. The present study demonstrates that the infill of the valley was not controlled by the forcing that caused its incision. Accumulation of the fluvial succession is discussed here in relation with localized, tectonic-controlled base levels, which commonly prevent from establishing of a clear downdip stratigraphic correlations. Chronological reconstruction of the study depositional dynamics provides solid constrains to frame them in the tectono-sedimentary evolution of the Northern Apennines.

Understanding the tectonics that gave rise to the formation of Tibet is critical to our understanding of crustal deformation processes. The unusual geomorphology of the drainage basins of East Asia's major rivers has been proposed to be the result of either (1) distortion and attenuation of antecedent drainages as India indents into Asia, which can therefore be used as passive strain markers of horizontal shear, or (2) due to fragmentation by river captures and flow reversals of an originally continental-scale drainage, in which the major East Asian rivers once flowed into the palaeo-Red River. If the latter hypothesis is correct, then it has been proposed that dating the drainage fragmentation constrains the timing of uplift of Tibet. A number of sedimentary provenance studies have been undertaken in order to determine whether the palaeo-Red River was once a river of continental proportions into which the upper reaches of the Yangtze, Salween, Mekong, Irrawaddy, and Yarlung drained. We have assessed the evidence that the Yarlung originally flowed into the palaeo-Red river, and then sequentially into the Irrawaddy and Brahmaputra, connecting to the latter first via the Lohit and then the Siang. For this river system, we have integrated our new data from the Paleogene-Recent Irrawaddy drainage basin (detrital zircon U-Pb with Hf and fission track, rutile U-Pb, mica Ar-Ar, bulk rock Sr-Nd, and petrography) with previously published data, to produce a palaeodrainage model that is consistent with all datasets. In our model, the Yarlung never flowed into the Irrawaddy drainage: during the Paleogene, the Yarlung suture zone was an internally drained basin, and from Neogene times onwards the Yarlung drained into the Brahmaputra in the Bengal Basin. The Central Myanmar Basin, through which the Irrawaddy River flows today, received predominantly locally-derived detritus until the Middle Eocene, the Irrawaddy initiated as a through-going river draining the Mogok Metamorphic Belt to the north sometime in the Late Eocene to Early Oligocene, and the river was then dominated by a stable MMB-dominated drainage throughout the Neogene to present day. Existing evidence does not support any connection between the Yarlung and the Red River in the past, but there is a paucity of suitable palaeo-Red River deposits with which to make a robust comparison. We argue that this limitation also precludes a robust assessment of a palaeo-connection between the Yangtze/Salween/Mekong and the Red River; it is difficult to unequivocally interpret the recorded provenance changes as the result of specific drainage reorganisations. We highlight the palaeo-Red River deposits of the Hanoi Basin as a potential location for future research focus in view of the near-complete Cenozoic record of undisputed palaeo-Red River deposits at this location. A majority of previous studies consider that if a major continental-scale drainage ever existed at all, it fragmented early in the Cenozoic. Such a viewpoint would agree with the growing body of evidence from palaeoaltitude studies that large parts of SE Tibet were uplifted by this period. This then leads towards the intriguing question as to the mechanisms which caused the major period of river incision in the Miocene in this region.\ud Keywords: Eastern Tibet; Palaeodrainage; Red River; Irrawaddy River; Yarlung Tsangpo; Central Myanmar Basin

In the Clusone Basin (a large intermontane basin filled by thick late Neogene-Quatern- ary sediments in the Middle Val Seriana, Southern Alps), two high-resolution seismic profiles have been acquired in order to reconstruct the geometries of the sediments that fill the depression, with a maximum thickness of more than 200 m as documented by available well data, and to define their relationships with the bedrock, consisting of Late Triassic carbonates. In addition to standard seismic reflection processing, a seismic refraction inversion technique has been applied. The integration of geological (both surface and well data) and seismic data indicates a complex history of the drainage patterns of the Clusone Basin, documenting a shift of the Serio River from a palaeodrainage toward the southeast (Val Borlezza) to the present situation, toward the south (Val Seriana): between the older and the present-day drainages an important depositional stage occurred, as documented by the thick sediments that fill the Clusone Basin, controlling the capture of the Serio River along the Val Seriana. Copyright 2004 John Wiley & Sons, Ltd.

The Pb isotopic composition of detrital K-feldspar grains can be rapidly measured using laser ablation MC-ICPMS. The feldspar Pb signal can survive weathering, transport and diagenesis, and careful targeting avoids problems with inclusions and alteration. As common Pb isotopic compositions show broad (100s km scale) variation across the continents, the method provides a powerful provenance tracer for feldspathic sandstones. Here we combine a new Pb domain map for the circum-North Atlantic with detrital feldspar Pb isotopic data for Triassic and Jurassic sandstones from basins on the Irish Atlantic margin. The Pb compositions reveal otherwise cryptic feldspar populations that constrain the evolving drainage pattern. Triassic sandstones were sourced from distant Archean and Paleoproterozoic rocks, probably in Greenland, Labrador and Rockall Bank to the NW, implying long (>500 km) transport across a nascent rift system. Later Jurassic sandstones had a composite Paleo- and Mesoproterozoic source in more proximal sources to the north (