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Geomorphology and Flooding
Published in Saeid Eslamian, Faezeh Eslamian, Flood Handbook, 2022
Giovanni Barrocu, Saeid Eslamian
The final result of erosion is the reduction of the land to a nearly flat surface, known as a peneplain. The time during which the reduction takes place is known as a cycle of erosion. Landforms, soil cover, and use strongly affect runoff, flood development, and effects.
Inversion tectonics in the Sorgenfrei–Tornquist Zone: insight from new marine seismic data at the Bornholm Gat, SW Baltic Sea
Published in GFF, 2022
Yaocen Pan, Elisabeth Seidel, Christopher Juhlin, Christian Hübscher, Daniel Sopher
Variscan-related tectonic processes resulted in Paleozoic strata remaining in grabens such as the Rønne Graben and the Colonus Shale Trough (Erlström et al., 1997). Following the basement uplift a peneplain was formed in the Middle-Late Permian and this resulted in deep erosion and truncation of titled Paleozoic strata, e.g., within the Colonus Shale Trough (Norling & Bergström, 1987; Mogensen, 1995). Overlying Triassic units rest unconformably on this peneplain. Subsequently, a Middle Jurassic erosional unconformity was formed by significant exhumation, roughly coeval to the North Sea doming, induced by the Mid-Cimmerian tectonic phase (Norling & Bergström, 1987; Mogensen, 1995). The thickness of Triassic strata varies significantly in the area, increasing from 60 to 70 m near Bornholm to more than 1000 m in the Rønne Graben (Erlström et al., 1997). Conglomerates and coarse sandstones are preserved in the grabens, topped by widely distributed Rhaetic deposits. Shallow marine clastics were later deposited in the late Jurassic to early Cretaceous, consisting commonly of clays, mudstones and siltstones. In the Hanö Bay Basin, scattered silica cemented Rhaetian (Upper Triassic) and Jurassic sandstones occur, due to deep erosion and weathering prior to the end of the Early Cretaceous (Erlström et al., 1997). An increased marine influx in the Valanginian was followed by the Hauterivian-Barremian regression, with the occurrence of shale and claystone in the Barremian, as well as a depositional hiatus during the Hauterivian, Barremian and Aptian (Erlström, 2020; Lindström & Erlström, 2011).
A revised Permian–Triassic stratigraphic framework for the northeastern Galilee Basin, Queensland, Australia, and definition of a new Middle–Upper Triassic sedimentary unit
Published in Australian Journal of Earth Sciences, 2022
C. N. Todd, E. M. Roberts, A. J. Charles
The Great Artesian Basin system formed after the final compressive phase of the Hunter–Bowen Orogeny, which deformed and inverted many of the Permian–Triassic terranes in eastern Australia between ca 235 and 230 Ma (Hoy & Rosenbaum, 2017; Li et al., 2012). Erosion of these units, including the New England Orogen and the Bowen Basin, provided a peneplain surface over which the Great Artesian Basin was deposited. This deformation is absent in the northeastern Galilee Basin (Van Heeswijck, 2010) and the Galilee and Eromanga basin boundary is marked by a disconformity. The ca 229.4 ± 3.6 Ma detrital zircon age of the Porcupine Gorge Formation is coincident with, or younger than, the final Hunter–Bowen compression and would suggest the overlying Warang Sandstone, and perhaps the Porcupine Gorge Formation itself—as exposed on the northeastern margins—could be interpreted as part of the Eromanga Basin stratigraphy.
Jurassic uplift and erosion of the northeast Queensland continental margin: evidence from (U–Th)/He thermochronology combined with U–Pb detrital zircon age spectra
Published in Australian Journal of Earth Sciences, 2020
Y. Cheng, C. N. Todd, R. A. Henderson, M. Danišík, F. Sahlström, Z. Chang, I. Corral
The basinal stratigraphy is subhorizonal and, apart from local minor fault offsets and broad, regional-scale warping, is undisturbed by tectonics. Its floor is an erosional surface of very low relief that cuts across disparate rock systems, including crystalline Proterozoic rocks in its northern and western parts, and deformed rocks of the Cambrian–Triassic Tasman Orogenic Zone in its eastern and southern parts. In some areas, the basin also overlies variably folded to flat-lying Paleozoic basins. The unconformity expressed by this erosional surface is a most profound and striking feature of Australian geology and is testament to Late Triassic tectonic quiescence and peneplain development across eastern Australia, followed by broad-scale, slow epeirogenic subsidence. The cause of subsidence remains speculative but its uniformity across heterogeneous crustal domains implies broad-scale sponsorship at depth, most likely within the asthenosphere, as widely argued as the cause of epeirogenesis in eastern Australia during the late Mesozoic and Cenozoic (DiCaprio, Gurnis, & Müller, 2009; Gurnis & Miller, 2003; Heine, Müller, Steinberger, & DiCaprio, 2010; Müller et al., 2016; Russell & Gurnis, 1994; Waschbusch, Korsch, & Beaumont, 2009).