Wemmer, Klaus

[["dc.bibliographiccitation.firstpage","817"],["dc.bibliographiccitation.issue","7"],["dc.bibliographiccitation.journal","Bulletin of Volcanology"],["dc.bibliographiccitation.lastpage","832"],["dc.bibliographiccitation.volume","72"],["dc.contributor.author","Lenhardt, Nils"],["dc.contributor.author","Böhnel, Harald"],["dc.contributor.author","Wemmer, Klaus"],["dc.contributor.author","Torres-Alvarado, Ignacio"],["dc.contributor.author","Hornung, Jens"],["dc.contributor.author","Hinderer, Matthias"],["dc.date.accessioned","2019-07-09T11:53:03Z"],["dc.date.available","2019-07-09T11:53:03Z"],["dc.date.issued","2010"],["dc.description.abstract","The volcaniclastic Tepoztlán Formation (TF) represents an important rock record to unravel the early evolution of the Transmexican Volcanic Belt (TMVB). Here, a depositional model together with a chronostratigraphy of this Formation is presented, based on detailed field observations together with new geochronological, paleomagnetic, and petrological data. The TF consists predominantly of deposits from pyroclastic density currents and extensive epiclastic products such as tuffaceous sandstones, conglomerates and breccias, originating from fluvial and mass flow processes, respectively. Within these sediments fall deposits and lavas are sparsely intercalated. The clastic material is almost exclusively of volcanic origin, ranging in composition from andesite to rhyolite. Thick gravity-driven deposits and large-scale alluvial fan environments document the buildup of steep volcanic edifices. K-Ar and Ar-Ar dates, in addition to eight magnetostratigraphic sections and lithological correlations served to construct a chronostratigraphy for the entire Tepoztlán Formation. Correlation of the 577 m composite magnetostratigraphic section with the Cande and Kent (1995) Geomagnetic Polarity Time Scale (GPTS) suggests that this section represents the time intervall 22.8–18.8 Ma (6Bn.1n-5Er; Aquitanian-Burdigalian, Lower Miocene). This correlation implies a deposition of the TF predating the extensive effusive activity in the TMVB at 12 Ma and is therefore interpreted to represent its initial phase with predominantly explosive activity. Additionally, three subdivisions of the TF were established, according to the dominant mode of deposition: (1) the fluvial dominated Malinalco Member (22.8–22.2 Ma), (2) the volcanic dominated San Andrés Member (22.2–21.3 Ma) and (3) the mass flow dominated Tepozteco Member (21.3–18.8 Ma)."],["dc.identifier.doi","10.1007/s00445-010-0361-z"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/6756"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/60329"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.publisher","Springer"],["dc.publisher.place","Berlin/Heidelberg"],["dc.relation.orgunit","Fakultät für Geowissenschaften und Geographie"],["dc.rights","Goescholar"],["dc.rights.uri","https://goescholar.uni-goettingen.de/licenses"],["dc.subject.ddc","550"],["dc.title","Petrology, magnetostratigraphy and geochronology of the Miocene volcaniclastic Tepoztlán Formation: implications for the initiation of the Transmexican Volcanic Belt (Central Mexico)"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1431"],["dc.bibliographiccitation.issue","6"],["dc.bibliographiccitation.journal","Geoscience Frontiers"],["dc.bibliographiccitation.lastpage","1445"],["dc.bibliographiccitation.volume","8"],["dc.contributor.author","Oriolo, Sebastián"],["dc.contributor.author","Oyhantçabal, Pedro"],["dc.contributor.author","Wemmer, Klaus"],["dc.contributor.author","Siegesmund, Siegfried"],["dc.date.accessioned","2019-07-09T11:44:31Z"],["dc.date.available","2019-07-09T11:44:31Z"],["dc.date.issued","2017"],["dc.description.abstract","Geological, geochronological and isotopic data are integrated in order to present a revised model for the Neoproterozoic evolution of Western Gondwana. Although the classical geodynamic scenario assumed for the period 800e700 Ma is related to Rodinia break-up and the consequent opening of major oceanic basins, a significantly different tectonic evolution can be inferred for most Western Gondwana cratons. These cratons occupied a marginal position in the southern hemisphere with respect to Rodinia and recorded subduction with back-arc extension, island arc development and limited formation of oceanic crust in internal oceans. This period was thus characterized by increased crustal growth in Western Gondwana, resulting from addition of juvenile continental crust along convergent margins. In contrast, crustal reworking and metacratonization were dominant during the subsequent assembly of Gondwana. The Río de la Plata, Congo-São Francisco, West African and Amazonian cratons collided at ca. 630 e600 Ma along the West Gondwana Orogen. These events overlap in time with the onset of the opening of the Iapetus Ocean at ca. 610e600 Ma, which gave rise to the separation of Baltica, Laurentia and Amazonia and resulted from the final Rodinia break-up. The East African/Antarctic Orogen recorded the subsequent amalgamation of Western and Eastern Gondwana after ca. 580 Ma, contemporaneously with the beginning of subduction in the Terra Australis Orogen along the southern Gondwana margin. However, the Kalahari Craton was lately incorporated during the Late EdiacaraneEarly Cambrian. The proposed Gondwana evolution rules out the existence of Pannotia, as the final Gondwana amalgamation postdates latest connections between Laurentia and Amazonia. Additionally, a combination of introversion and extroversion is proposed for the assembly of Gondwana. The contemporaneous record of final Rodinia break-up and Gondwana assembly has major implications for the supercontinent cycle, as supercontinent amalgamation and break-up do not necessarily represent alternating episodic processes but overlap in time."],["dc.identifier.doi","10.1016/j.gsf.2017.01.009"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/14809"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/59029"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.relation.issn","1674-9871"],["dc.relation.orgunit","Fakultät für Geowissenschaften und Geographie"],["dc.relation.orgunit","Abteilung Strukturgeologie und Geodynamik"],["dc.rights","CC BY-NC-ND 4.0"],["dc.rights.uri","http://creativecommons.org/licenses/by-nc-nd/4.0/"],["dc.subject.ddc","550"],["dc.title","Contemporaneous assembly of Western Gondwana and final Rodinia break-up: Implications for the supercontinent cycle"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","31"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Swiss Journal of Geosciences"],["dc.bibliographiccitation.lastpage","54"],["dc.bibliographiccitation.volume","101"],["dc.contributor.author","Mikes, Tamas"],["dc.contributor.author","Christ, Dominik"],["dc.contributor.author","Petri, Rüdiger"],["dc.contributor.author","Dunkl, István"],["dc.contributor.author","Frei, Dirk"],["dc.contributor.author","Báldi-Beke, Mária"],["dc.contributor.author","Reitner, Joachim"],["dc.contributor.author","Wemmer, Klaus"],["dc.contributor.author","Hrvatović, Hazim"],["dc.contributor.author","Eynatten, Hilmar von"],["dc.date.accessioned","2019-07-09T11:53:02Z"],["dc.date.available","2019-07-09T11:53:02Z"],["dc.date.issued","2008"],["dc.description.abstract","Sandwiched between the Adriatic Carbonate Platform and the Dinaride Ophiolite Zone, the Bosnian Flysch forms a c. 3000 m thick, intensely folded stack of Upper Jurassic to Cretaceous mixed carbonate and siliciclastic sediments in the Dinarides. New petrographic, heavy mineral, zircon U/Pb and fission-track data as well as biostratigraphic evidence allow us to reconstruct the palaeogeology of the source areas of the Bosnian Flysch basin in late Mesozoic times. Middle Jurassic intraoceanic subduction of the Neotethys was shortly followed by exhumation of the overriding oceanic plate. Trench sedimentation was controlled by a dual sediment supply from the sub-ophiolitic high-grade metamorphic soles and from the distal continental margin of the Adriatic plate. Following obduction onto Adria, from the Jurassic–Cretaceous transition onwards a vast clastic wedge (Vranduk Formation) was developed in front of the leading edge, fed by continental basement units of Adria that experienced Early Cretaceous synsedimentary cooling, by the overlying ophiolitic thrust sheets and by redeposited elements of coeval Urgonian facies reefs grown on the thrust wedge complex. Following mid-Cretaceous deformation and thermal overprint of the Vranduk Formation, the depozone migrated further towards SW and received increasing amounts of redeposited carbonate detritus released from the Adriatic Carbonate Platform margin (Ugar Formation). Subordinate siliciclastic source components indicate changing source rocks on the upper plate, with ophiolites becoming subordinate. The zone of the continental basement previously affected by the Late Jurassic–Early Cretaceous thermal imprint has been removed; instead, the basement mostly supplied detritus with a wide range of pre-Jurassic cooling ages. However, a c. 80 Ma, largely synsedimentary cooling event is also recorded by the Ugar Formation, that contrasts the predominantly Early Cretaceous cooling of the Adriatic basement and suggests, at least locally, a fast exhumation."],["dc.identifier.doi","10.1007/s00015-008-1291-z"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/6684"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/60324"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.relation.orgunit","Fakultät für Geowissenschaften und Geographie"],["dc.rights","Goescholar"],["dc.rights.uri","https://goescholar.uni-goettingen.de/licenses"],["dc.subject.ddc","550"],["dc.title","Provenance of the Bosnian Flysch"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]