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Transport And Emplacement Of Ignimbrites And Resedimented Volcaniclastics From Gutai Mts., Eastern Carpathians, Romania, Alexandrina FüLöP
Transport And Emplacement Of Ignimbrites And Resedimented Volcaniclastics From Gutai Mts., Eastern Carpathians, Romania, Alexandrina FüLöP
Studia UBB Geologia
Gutâi Mts. had started to be built up in Middle Miocene, ca. 15.4 Ma ago. A series of explosive events developed starting with a major magmatic explosion and caldera collapse responsible for large volumes of ignimbrites. Successive explosions followed caldera collapse triggering a series of pyroclastic currents that underwent subsequent reworking. Mass flow has been the main transport mechanism recorded by the sedimentary structures of either ignimbrites or post-ignimbrites volcaniclastics. Multiple ignimbrite units resulted from subaerial mass flows, successively emplaced by progressive aggradation from the basal layer of a density-stratified pyroclastic current. The overlying sequence is composed of different volcaniclastics …
Petrology Of Badenian Ignimbrites, Gutai Mts. (Eastern Carpathians), Alexandrina FüLöP, Marinel Kovacs
Petrology Of Badenian Ignimbrites, Gutai Mts. (Eastern Carpathians), Alexandrina FüLöP, Marinel Kovacs
Studia UBB Geologia
Gutâi Mts., part of inner Carpathians volcanic arc, consist of products of felsic and intermediate volcanism. The previously known “Badenian Rhyodacitic Formation”, expression of the felsic explosive volcanism, is composed of a well-defined basal unit of ignimbrites, overlain by a sequence of resedimented volcaniclastics of similar origin, interlayered with mudstones. The petrography of ignimbrites shows matrix-supported lapilli tuffs having a heterogeneous composition with insignificant lateral variations. The juvenile components, pumice, glass shards and crystals of plagioclase, quartz and biotite are predominant; cognate nonvesicular glassy clasts are rare, unlike accidental clasts of sedimentary and metamorphic rocks which are abundant. Pyroxene andesite …
Transport And Emplacement Of The 15.4 Ma Rhyolitic Ignimbrites From Gutai Mts., Eastern Carpathians, Alexandrina FüLöP
Transport And Emplacement Of The 15.4 Ma Rhyolitic Ignimbrites From Gutai Mts., Eastern Carpathians, Alexandrina FüLöP
Studia UBB Geologia
The 15.4 Ma rhyolitic ignimbrites are the first volcanic products from Gutâi Mts. The study of their sedimentary structures reflects the mechanisms involved in the transport and emplacement of the parental flows, essential to inffering the style of eruption and the source evolution and location. Primary sedimentary structures show massive deposits emplaced from mass flows, sequence of units showing the normal coarse-tail grading of the dense clasts and the reverse coarse-tail grading of the pumice clasts. They reflect concentrated laminar flows or dilute, subcritical flows emplaced by progressive aggradation. Secondary sedimentary structures are represented by the eutaxitic texture or welding, …
A Paleoecological Reconstruction Of The Late Glacial And Holocene Based On Multidisciplinary Studies At Steregoiu Site (Gutai Mts., Romania), Angelica Feurdean, Leif BjöRkman, Barbara Wohlfarth
A Paleoecological Reconstruction Of The Late Glacial And Holocene Based On Multidisciplinary Studies At Steregoiu Site (Gutai Mts., Romania), Angelica Feurdean, Leif BjöRkman, Barbara Wohlfarth
Studia UBB Geologia
High resolution analyses of pollen, mineral magnetic properties, loss of ignition, lithostratigraphy and AMS 14C measurements of lake sediments and peat deposits accumulated in the former crater lake of Steregoiu (Gutâiului Mts., NW Romania), gave new and important information about vegetation and climate changes from the period GS-2 to the present. During the Lateglacial, three cold events were recorded: before 14,700 cal. years BP (GS-2), 14,050–13,800 cal. years BP (GI-1d), 12,900-11,500 cal. years BP (GS-1), and a warm climatic event between 13,800-12,950 cal. years BP (GI-1c to GL-1a). The Late Glacial/Holocene transition around 11,500 cal. years BP, was determined by …