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Schildgen, T. F.
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- PublicationRestrictedConstruction and degradation of a broad volcanic massif: The Vicuña pampa volcanic complex, southern central Andes, NW Argentina(2017-05)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ;The Vicuña Pampa volcanic complex, at the SE edge of the arid Puna Plateau of the Central Andes, records the interplay between volcanic construction and degradational processes. The low-sloping Vicuña Pampa volcanic complex, with a 1200-mdeep, southeastward- opening depression, was previously interpreted as a collapse caldera based on morphological considerations. However, characteristic features associated with collapse calderas do not exist, and close inspection instead suggests that the Vicuña Pampa volcanic complex is a strongly eroded, broad, massif-type composite volcano of mainly basaltic to trachyandesitic composition. Construction of the Vicuña Pampa volcanic complex occurred during two distinct cycles separated by the development of the depression. The first and main cycle took place at ca. 12 Ma and was dominated by lava flows and subordinate scoria cones and domes. The second cycle, possibly late Mio-cene in age, affected the SW portion of the depression with the emplacement of domes. We interpret the central depression as the result of a possible sector collapse and subsequent intense fluvial erosion during middle to late Miocene time, facilitated by faulting, steepened topography, and wetter climate conditions compared to today. We estimate that ~65% of the initial edifice of ~240 km3 was degraded. The efficiency of degradation processes for removing mass from the Vicuña Pampa volcanic complex is surprising, considering that today the region is arid, and the stream channels within the complex are predominantly transport limited, forming a series of coalesced, aggraded alluvial fans and eolian infill. Hence, the Vicuña Pampa volcanic complex records the effects of past degradation efficiency that differs substantially from that of today.617 3 - PublicationRestrictedEasternmost Mediterranean evidence of the Zanclean flooding event and subsequent surface uplift: Adana Basin, southern Turkey(2012)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Cipollari, P.; Università Roma Tre ;Cosentino, D.; Università Roma Tre ;Radeff, G.; Università Roma Tre ;Schildgen, T. F.; Universitat Potsdam, Potsdam, Germany ;Faranda, C.; Università Roma Tre ;Grossi, F.; Università Roma Tre ;Gliozzi, E.; Università Roma Tre ;Smedile, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Gennari, R.; Università di Parma ;Darbas, G.; Sutcu imam Universitesi, Kahramanmaras, Turkey ;Dudas, F. O.; Institute of Technology, Cambridge, USA ;Gurbuz, K.; Cukurova Universitesi, Adana, Turkey ;Nazik, A.; Cukurova Universitesi, Adana, Turkey ;Hechtler, H.; Deutsches GeoForschungsZentrum (GFZ), Potsdam, Germany; ; ; ; ; ; ; ; ; ; ; ; ; According to the literature, the Adana Basin, at the easternmost part of the Mediterranean Basin in southern Turkey, records the Pliocene stage with shallow-marine to fluvial deposits. Our micropalaeontological analysis of samples from the Adana Basin reveal Late Lago–Mare biofacies with Paratethyan ostracod assemblages pertaining to the Loxocorniculina djafarovi zone. Grey clays rich in planktonic foraminifera lie above the Lago–Mare deposits. Within the grey clays, the continuous occurrence of the calcareous nannofossil Reticulofenestra zancleana and the base of the Reticulofenestra pseudoumbilicus paracme points to an Early Zanclean age (5.332–5.199 Ma). Both ostracod and benthic foraminifera indicate epibathyal and bathyal environments. 87Sr/86Sr measurements on planktonic and benthic foraminifera fall below the mean global ocean value for the Early Zanclean, indicating potentially insufficient mixing of low 87Sr/86Sr Mediterranean brackish ‘Lago–Mare’ water with the global ocean in the earliest Pliocene.We utilize the ages and palaeodepths of the marine sediments together with their modern elevations to determine uplift rates of the Adana Basin of 0.06 to 0.13 mm a21 since 5.2–5.3 Ma (total uplift of 350–650 m) from surface data, and 0.02–0.13 mm a21 since c. 1.8 Ma (total uplift of 30–230 m) from subsurface data.363 39