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We present new age constraints for the late Miocene Volkovce Formation of Slovakia, alluvial facies that accumulated adjacent to Lake Pannon. Facies analysis and authigenic 10Be/9Be dating was undertaken at the Bernolákovo and Triblavina localities while the latter outcrop also yielded additional small mammal and mollusk assemblages as well as remains of flora. The results of seven radiometric dating ages yielded a weighted mean age of 9.65 ± 0.61 Ma for the Triblavina outcrop and 8.85 ± 0.32 Ma for the Bernolákovo outcrop. The small mammal assemblage at the Triblavina outcrop is indicative of the lowermost MN11 zone, which in the Western European standard definition suggests an age of <8.9 Ma. The ~0.1 Ma inconsistency between absolute dating and biostratigraphic dating at the Triblavina outcrop might be explained either by the variation of initial 10Be/9Be ratio in the depositional environment or/and by diachronous development of the mammal faunas across the Europe. The mollusk assemblage at this outcrop indicates the paleoenvironment of freshwater lakes affected by rivers with evidence for a nearby riparian forests; it may be roughly correlated with Papp's lithostratigraphic units G and H defined for the Pannonian stage in the Vienna Basin. Our results provide a detailed insight to the late Miocene stratigraphy and terrestrial environments alongside the Lake Pannon shoreline. • New late Miocene micromammal fauna refines the timing of environmental changes during lowermost MN11. • Mammals, gastropods and flora from Triblavina outcrop in SW Slovakia point to humid climate. • Poorly-drained floodplain (pond-dominated) replaced by meandering river with well-drained floodplain. • Authigenic 10Be/9Be weighted mean ages 9.65 ± 0.61 Ma (Triblavina) and 8.85 ± 0.32 Ma (Bernolákovo). • Only 0.1 Myr difference between datings could relate to MN zones heterochronicity. [ABSTRACT FROM AUTHOR]

The terraces south of the Danube River have been strongly dissected by faults related to thesinistral movement of the Vienna Basin Transform Fault System (VBTF, Decker et al., 2005).Each fault block displays a slightly different succession of terraces whose altitudes rangingbetween 25 and 130 m and might be offset. However, fault-related vertical displacementsalong the Danube have not yet been quantified. In this study the 26Al and 10Be cosmogenic nuclide pair has been used to quantify theburial duration in a terrace at Haslau and at Rauchenwarth, which are ∼40 m and ∼75 mabove the river and considered as Middle- and Early Pleistocene, respectively. These terracesand the related outcrops are located to the east and west of the VBTF. Determining theiremplacement ages might help to quantify the differential vertical movement of the Arbesthaland Rauchenwarth blocks. The sample set from the Haslau terrace consisted of quartzite cobbles taken at twosubsurface depths (5.5 m and 11.8 m) for isochron burial dating (Balco and Rovey, 2008).After crushing and sieving, the samples were divided between the cosmogenic nuclidelaboratories at Vienna and Budapest and duplicate samples were processed independently.The results demonstrate that the laboratory background allows secure in-situ producedcosmogenic 10Be and 26Al extraction at both laboratories. At Rauchenwarth, quartzitecobbles and a sand sample were taken at 11 m depth. The mean minimum burial age (assuming no post-burial production) at Haslau is 0.8±0.1Ma (n=8) and 1.0±0.2 Ma at Rauchenwarth (n=4). The maximum uplift rate calculatedusing the minimum ages is 65-100 m/Ma at Rauchenwarth and 40-55 m/Ma atHaslau Interestingly, the numerical age of the Haslau terrace is older, and that of theRauchenwarth Plateu is younger than previously suggested. However, at Haslau, outliers withboth higher and lower 26Al/10Be ratios requires further consideration of the burial duration.Significant scatter of the 26Al/10Be nuclide ratio suggest that part of the terrace sedimentmay originate from older terraces, which would violate the main requirement forisochron burial dating of all clasts sharing a similar 26Al/10Be ratio at the time ofdeposition. Thanks to NKFIH 83610, 124807; OMAA 90öu17, 98öu17; the INSU/CNRS, the ANRthrough the program "EQUIPEX Investissement d&#x2019;Avenir" and IRD. References Balco, G., Rovey, C., 2008. Am. J. of Science 308, 1083-1114. Decker, K., et al., 2005. Quat. Sci. Rev. 24, 305-320. [ABSTRACT FROM AUTHOR]

Numerous studies have conjectured a strong effect of climatically-induced loading/unloading of the earth surface (by sea level or ice-sheet fluctuations) on the volcanic activity. If the impact of surface unloading on volcanism in continuously active volcanic areas, for instance in Iceland, is convincing, we may ask about the impact of surface unloading in less active areas or regions characterized by much more discontinuous volcanic activity. We explore this question by considering the Cenozoic Volcanic region of the Eastern Cordillera of Bolivia, part of the Altiplano-Puna volcanic province. There, a large ignimbrite plateau, the Los Frailes complex, is the product of a prolonged period of volcanic activity: thick Miocene ignimbrites were followed by a volcanic activity characterized by several domes intrusion and tuff/ignimbrite deposits between 5.2 and 1.24 Ma (Jimenez and Lopez-Velasquez, 2008). The volcanic quiescence since the early Pleistocene was recently and surprisingly interrupted along the South-Western domain of the Los Frailes plateau by the extrusion of several domes or domes/coulées of dacite (the Nuevo Mundo summits), accompanied by ash and pumice effusive activity. These domes, which present a similar per-aluminous composition as the Pliocene Los Frailes ignimbrites and which were erupted along a N-S trending fault, clearly overlie LGM glacial landforms and moraines. To understand the origin of this late dacitic activity, we precisely dated the northern dome by carrying out 10Be exposure ages on several blocks sampled along the top surface of the dome. Exposure ages display clustered values at ~11.7 kyr, i.e. ~3kyr after the rapid deglaciation that occurred in the region at the end of the Tauca period (16.5-14.5 kyr) (Blard et al., 2009). The 2-D modelling of the glacier extension indicates that a small ice-field (15x40 km) covered during the LGM the SW part of the Los Frailes plateau, with ice thickness locally exceeding 300m. The rapid glacier retreat at ~14.5 kyr produced rapid unloading with a maximum pressure drop (~5 bars at 10km depth) located right below the dacitic domes. The observations and models strongly suggest that the dacitic domes extrusion has been triggered by the glacier unloading, which induced overpressure at depth in the magma chamber. Additionally, magma ascent might have been facilitated by a horizontal stress drop on the N-S fault along which the Late Pleistocene domes are aligned. The observed time lag between unloading and surface extrusion is in good agreement with Jellineck et al.'s (2003) model for silicic magmas. If so, the Nuevo Mundo domes may be issued from a magma chamber at shallow depth (5-10km ?) containing silicic magma, with sustained replenishment during the Pleistocene but without effusive activity, except when climate interaction push the system out of its steady cooling evolution at depth. [ABSTRACT FROM AUTHOR]