The timing and pattern of surface uplift of Miocene marine sediments capping the southern margin of the Central Anatolian Plateau in southern Turkey provide a fi rst-order constraint on possible mechanisms of regional uplift. Nannofossil, ostracod, and planktic foraminifera biostratigraphy of the Başyayla section (Mut-Ermenek Basin) within the Mut and Köselerli Formations suggests a Tortonian age for marine sediments unconformably capping basement rocks at ~2 km elevation. The identifi cation of biozone MMi 12a (7.81-8.35 Ma) from planktic foraminifera in the upper part of the section provides the tightest constraint on the age, which is further limited to 8.35-8.108 Ma as a result of the reverse polarity of the collected samples (chron 4r.1r or 4r.2r). This provides a limiting age for the onset of surface uplift at the margin of one of the world's major orogenic plateaus, from which an average uplift rate of 0.24-0.25 mm/yr can be calculated.Subhorizontal beds of the uppermost marine sediments exposed throughout the Mut-Ermenek Basin suggest minimal localized deformation, with just minor faulting at the basin margin and broad antiformal deformation across the basin. This implies that the post-8 Ma uplift mechanism must be rooted deep within the crust or in the upper mantle. Published Pn-wave velocity data for the region are compatible with topography compensated by asthenosphere across the southern margin of the plateau, showing a close match to the highest topography when elevations are fi ltered with a 100-km-wide smoothing window. Uplift along the southern margin of the Central Anatolian Plateau is also refl ected by the pattern of Miocene marine sediments capping the margin, which form an asymmetric drape fold over the topography. These observations, together with tomographic evidence for slab steepening and break-off beneath the Eastern Anatolian Plateau, suggest that at least some of the ~2 km of post-8 Ma uplift of the southern Central Anatolian Plateau margin is compensated by low-density asthenospheric mantle that upwelled following slab break-off. their employment. Individual scientists are hereby granted permission, without fees or furtherCopyright not claimed on content prepared wholly by U.S. government employees within scope of Notes
[1] We present paleomagnetic, rock magnetic and scanning electron microscope data from three upper Messinian stratigraphic sections from the Adana Basin (southern Turkey). The collected samples are from fine-grained units, which were deposited during the Messinian Salinity Crisis (within subchron C3r). Paleomagnetic results reveal an inconsistent polarity record, related to a mixture of magnetite and greigite that hinders determination of a reliable magnetostratigraphy. Three classes of samples are recognized on the basis of paleomagnetic results. The first is characterized by a single magnetization component, with normal polarity, that is stable up to 530-580 C and is carried by magnetite. The second is characterized by a single magnetization component, with reversed polarity, that is stable up to C. This magnetization is due to greigite, which developed after formation of slumps and before tectonic tilting of the studied successions. The third is characterized by reversed polarity, which is stable up to 530-580 C. We interpret this component as a primary magnetization carried by fine-grained and magnetically stable detrital magnetite. Results indicate that in the Adana Basin the assumption that a primary magnetization is carried by magnetite, and a magnetic overprint carried by greigite, does not hold because a late magnetic overprint has also been found for
This paper illustrates a geographic information system (GIS) supported methodology for the assessment of landslide susceptibility. The methodology involves four operational steps: survey, site analysis, macroarea analysis and susceptibility analysis. The Survey includes the production (or acquisition) of a large-scale litho-technical map, a large-scale geomorphological map, a detailed inventory of past and present landslide events, and a high resolution DTM (Digital Terrain Model. Site analysis leads to the definition of discriminating parameters (commonly, lithological and morphometric conditions necessary but not sufficient to trigger a landslide of a given type) and predisposing factors (conditions that worsen slope stability but are not sufficient to trigger a landslide of a given type in the absence of discriminating parameters). The different predisposing factors are subdivided into classes, whose intervals are established by descriptive, statistical analysis of landslide inventory data. A numerical index, based on the frequency of landslide occurrence, quantifies the contribution of each class to slope instability.Macro-area analysis includes the generation of Litho-Morphometric Units (LMU) by overlaying discriminating parameters, manual drawing of LMU envelopes (macro-areas), generation of predisposing factor maps from the spatial distribution of predisposing factors, and heuristic weighting of predisposing factor indices. Susceptibility analysis includes the generation of Homogeneous Territorial Units (HTU) by overlaying macroareas and predisposing factor maps, and the application of a susceptibility function to the different HTU. The resulting values are normalized before the generation of the landslide susceptibility maps. The methodology has been applied to the Fiumicino River catchment, located in the western side of Latium Apennine (Central Italy) between 200 and 1300 m a.s.l. and developed on Late Miocene calcarenites, sandstones with clay intercalations, and marls. The resulting landslide susceptibility maps will be employed in environmental management. They also represent the preliminary step for the assessment of landslide hazard and risk.
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