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Projects – Biodiversity and global changes in geological history

The projects investigated by the Czech Geological Survey within the frame of the main research priority "Biodiversity and global changes in geological history" of the CGS Research Strategic Plan for 2016–2020.

611300

Searching for biological fingerprints and grain alteration patterns in Devonian and Carboniferous microbial facies - examples from the Bohemian Massif

In this project we investigate putative microbialite facies associated with one of the most severe extinction evens of the Phanerozoic, the Late Devonian Kellwasser and Hangenberg events, and on the two preceding Middle Devonian Basal Choteč and Kačák events. We intend to focus on internal arrangement and fabric of micritic precipitates in order to assess the role of taphonomy in the formation and preservation of recorded microstructures, and to decipher modes and patterns in grain alteration and peloid formation within the mentioned stratigraphic levels. We further aim to test whether extinctions at the end of Devonian influenced the structure of microbial biota. To document and compare the range of morphologies at ultrastructural level using SEM and to assess spatial and textural relations of carbonate precipitates is essential in our investigation but in addition to that, REE+Y analysis will be carried out as it has proved to represent promising additional fingerprint of microbial involvement in carbonate precipitation.

Project manager: Mgr. Stanislava Vodrážková, Ph.D. Duration of the project: 01.01.2020–30.06.2023

648000

Cherts and carbonates as geochemical proxies of paleoenvironmental conditions and Ocean Plate Stratigraphy

Cherts and carbonates represent outstanding and widespread members of Ocean Plate Stratigraphy (OPS) from the Archean to present. Their composition reflects different conditions during their deposition, which can be potentially linked to the contrasting and temporally changing processes that occurred on moving oceanic plates. Additionally, they also provide unique insights into the compositional variations in seawater chemistry and temperature as well as redox conditions of their depositional environment. We will pursue a multi-technique study combining tectonic, structural, and stratigraphic observations with elemental and isotopic (Hf–Nd–Mo–Si–C–O) data to reveal the origin and nature of chert and carbonate successions in ancient OPS sections and test whether they can be used as geochemical proxies for the variable processes occurring on oceanic plates. The project will also contribute to our understanding of paleoenvironmental conditions during the late Proterozoic–Cambrian with implications for global events preceding and synchronous with the Great Cambrian Explosion of life.

Project manager: RNDr. Jan Pašava, CSc. Duration of the project: 01.01.2020–30.06.2023

648100

Biostratigraphy and faunal dynamics of the Silurian pelagic biota of the Prague Basin in the context of major environmental changes and perturbations

The project proposes a general revision and update of the Silurian graptolite and conodont biostratigraphy of the Prague Basin based on a series of reference sections. High-resolution graptolite biozonation is primarily applied in off-shore successions, the conodont biozonation is a first choice in limestone-dominated facies. The two extinct groups of the pelagic fauna are rarely found together but both co-occur with pelagic cephalopods in middle and upper Silurian sections. Correlation of the two parallel zonal schemes will be tested using time specific indices of major and global environmental changes, such as mass faunal extinctions, carbon isotope excursions, facies changes and unconformities. Faunal dynamics of the principal pelagic biota (graptolites, conodonts and cephalopods) will be inferred from species richness, origination and extinction events and morphological disparity, and based on revised species range charts. Available and new biostratigraphic data obtained from at least 59 sampled sections will elucidate nature, selectivity and timing of the global bioevents.

Project manager: RNDr. Štěpán Manda Duration of the project: 01.01.2020–30.06.2023

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Czech Geological Survey
Geologická 577/6
152 00 Praha 5
phone: +420251085347
jiri.fryda@geologycz