Paleontological evidence of Upper Proterozoic (Vendian) in the "Zone Münchberg-Frankenberg"

Heuse, Thomas; Kurze, Manfred; Reitz, Erhard

doi:10.1127/njgpm/1994/1994/95

Cited by 2 publications

(4 citation statements)

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“…3. The stratigraphic age of metasediments in the upper part of the Schist Cover, dated palynologically as Neoproterozoic (Heuse et al, 1994(Heuse et al, , 2010, is not older than Middle/Upper Devonian boundary time, based on detrital zircon dating, and thus fits well into the right-way-up sequence of the Schist Cover. 4.…”

mentioning

confidence: 81%

“…P-T estimates of 0.3 GPa and 660-680°C obtained at the bottom of the Schist Cover (Rötzler & Romer, 2010) imply post-peak extensional telescoping, as the existing rock column overhead is less than half as thick as required to exert a corresponding, essentially lithostatic pressure. Based on palynomorph stratigraphy, Heuse, Kurze, and Reitz (1994) and Heuse et al (2010) inferred a Late Neoproterozoic age for deposits higher in the southeastern Schist Cover. If this age were correct, detrital zircon ages indicating younger deposits deeper in the Schist Cover (Rötzler & Romer, 2010) would involve an inverted stratigraphy.…”

Section: Geological Settingmentioning

confidence: 99%

“…Muscovite fish were Ar-Ar dated. Graphite-bearing quartz-mica schist (sample 359/186b) intercalated with metabasite has yielded palynomorph microfossils of uncertain Neoproterozoic age (Heuse et al, 1994(Heuse et al, , 2010. The upper greenschist to amphibolite facies rock with alternating phyllosilicate and quartz-rich layers has a wavy to crenulated foliation parallel to compositional layering.…”

Section: Schist Covermentioning

confidence: 99%

“…Consequently, if the zircon saturation models are correct and magmatic zircon is truly present in the MORB-type rocks compiled in Table 3, then the zircon growth liquid did not match the respective bulk rock composition. Heuse et al (1994Heuse et al ( , 2010 correlated metasediments from the upper part of the Schist Cover of the SGM with various Saxothuringian sedimentary deposits dated by palynology as Neoproterozoic and by U-Pb zircon chronology as Ediacaran. However, detrital zircon ages from our sample 359/186b preclude that the said metasediments are older than Middle/ Upper Devonian boundary time (Figure 17d).…”

Section: Rötzler and Timmermanmentioning

confidence: 99%

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Geochronological and petrological constraints from the evolution in the Saxon Granulite Massif, Germany, on the Variscan continental collision orogeny

Rötzler

Timmerman

2020

Journal Metamorphic Geology

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Controversy over the plate tectonic affinity and evolution of the Saxon granulites in a two‐ or multi‐plate setting during inter‐ or intracontinental collision makes the Saxon Granulite Massif a key area for the understanding of the Palaeozoic Variscan orogeny. The massif is a large dome structure in which tectonic slivers of metapelite and metaophiolite units occur along a shear zone separating a diapir‐like body of high‐P granulite below from low‐P metasedimentary rocks above. Each of the upper structural units records a different metamorphic evolution until its assembly with the exhuming granulite body. New age and petrologic data suggest that the metaophiolites developed from early Cambrian protoliths during high‐P amphibolite facies metamorphism in the mid‐ to late‐Devonian and thermal overprinting by the exhuming hot granulite body in the early Carboniferous. A correlation of new Ar–Ar biotite ages with published P–T–t data for the granulites implies that exhumation and cooling of the granulite body occurred at average rates of ~8 mm/year and ~80°C/Ma, with a drop in exhumation rate from ~20 to ~2.5 mm/year and a slight rise in cooling rate between early and late stages of exhumation. A time lag of c. 2 Ma between cooling through the closure temperatures for argon diffusion in hornblende and biotite indicates a cooling rate of 90°C/Ma when all units had assembled into the massif. A two‐plate model of the Variscan orogeny in which the above evolution is related to a short‐lived intra‐Gondwana subduction zone conflicts with the oceanic affinity of the metaophiolites and the timescale of c. 50 Ma for the metamorphism. Alternative models focusing on the internal Variscan belt assume distinctly different material paths through the lower or upper crust for strikingly similar granulite massifs. An earlier proposed model of bilateral subduction below the internal Variscan belt may solve this problem.

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mentioning

confidence: 81%

Section: Geological Settingmentioning

confidence: 99%

Section: Schist Covermentioning

confidence: 99%

Section: Rötzler and Timmermanmentioning

confidence: 99%

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