Sea-level changes vs. organic productivity as controls on Early and Middle Devonian bioevents: Facies- and gamma-ray based sequence-stratigraphic correlation of the Prague Basin, Czech Republic

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F18%3A00107792" target="_blank" >RIV/00216224:14310/18:00107792 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/67985831:_____/18:00482899 RIV/61989592:15310/18:73590894

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S0921818117303089" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0921818117303089</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.gloplacha.2017.11.009" target="_blank" >10.1016/j.gloplacha.2017.11.009</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Sea-level changes vs. organic productivity as controls on Early and Middle Devonian bioevents: Facies- and gamma-ray based sequence-stratigraphic correlation of the Prague Basin, Czech Republic

Popis výsledku v původním jazyce

The Devonian marine stratigraphic record is characterized by a number of bioevents overturns in pelagic and benthic faunal assemblages, which are associated with distinct changes in lithology. The coincidence of litho logic and biotic changes can be explained by the causal link between biotic evolution, carbonate production and relative sea-level changes. To gain insight into the sea-level history of Early and Middle Devonian bioevents (the Lochkovian/Pragian Event, Basal Zlichovian E., Daleje E., and Chotec E.) we carried out a sequence-stratigraphic analysis of carbonate-dominated successions in the Prague Basin (peri-Gondwana), a classic area of Devonian bioevents. The study is based on a basin-wide correlation of facies and field gamma-ray spectrometry (GRS) logs from 18 sections (Lochkovian to Eifelian), supported by element geochemistry and published biostratigraphic and carbon isotope data. Devonian carbonate deposition in the Prague Basin alternated between two end member modes: an oligotrophic, homoclinal ramp (Praha and Daleje-Trebotov Formations) and a mesotrophic, distally steepened ramp (Lochkov, Zlichov, and Chotec Formations). They show contrasting facies, particularly the absence/presence of gravity-flow deposits, allochem composition, U/Th ratios, and geochemical composition (productivity proxies such as P/Al, Si/Al, Zn/Al, TOC and stable carbon isotopes). The mesotrophic systems reflect an increased availability of nutrients on the shelf during the late Lochkovian, early Emsian (Zlichovian), and Eifelian periods when sea surface temperature, pCO(2), and silicate weathering rates ware higher. The oligotrophic systems deposited during the Pragian to-earliest Emsian and late Emsian (Dalejan) periods reflect reversed palaeoclimatic trends. We identified three depositional sequences (DS), DS1 (base of Pragian to early Emsian); DS2 (early Emsian to mid Emsian); and DS3 (mid Emsian to mid Eifelian). These sequences were integrated into a peri-Gondwana relative sea-level curve, which was then compared with the Euramerican sea level curve of Johnson et al. (1985). The bioevents coincided with several sequence stratigraphic surfaces, representing variable limbs of the relative sea-level curve. On the other hand, their conspicuous coincidence with the switching intervals between the colder oligotrophic and warmer mesotrophic modes suggests that organic production linked to global climate was the primary control on biotic overturns, while sea-level fluctuations may have only amplified its effects.

Název v anglickém jazyce

Sea-level changes vs. organic productivity as controls on Early and Middle Devonian bioevents: Facies- and gamma-ray based sequence-stratigraphic correlation of the Prague Basin, Czech Republic

Popis výsledku anglicky

The Devonian marine stratigraphic record is characterized by a number of bioevents overturns in pelagic and benthic faunal assemblages, which are associated with distinct changes in lithology. The coincidence of litho logic and biotic changes can be explained by the causal link between biotic evolution, carbonate production and relative sea-level changes. To gain insight into the sea-level history of Early and Middle Devonian bioevents (the Lochkovian/Pragian Event, Basal Zlichovian E., Daleje E., and Chotec E.) we carried out a sequence-stratigraphic analysis of carbonate-dominated successions in the Prague Basin (peri-Gondwana), a classic area of Devonian bioevents. The study is based on a basin-wide correlation of facies and field gamma-ray spectrometry (GRS) logs from 18 sections (Lochkovian to Eifelian), supported by element geochemistry and published biostratigraphic and carbon isotope data. Devonian carbonate deposition in the Prague Basin alternated between two end member modes: an oligotrophic, homoclinal ramp (Praha and Daleje-Trebotov Formations) and a mesotrophic, distally steepened ramp (Lochkov, Zlichov, and Chotec Formations). They show contrasting facies, particularly the absence/presence of gravity-flow deposits, allochem composition, U/Th ratios, and geochemical composition (productivity proxies such as P/Al, Si/Al, Zn/Al, TOC and stable carbon isotopes). The mesotrophic systems reflect an increased availability of nutrients on the shelf during the late Lochkovian, early Emsian (Zlichovian), and Eifelian periods when sea surface temperature, pCO(2), and silicate weathering rates ware higher. The oligotrophic systems deposited during the Pragian to-earliest Emsian and late Emsian (Dalejan) periods reflect reversed palaeoclimatic trends. We identified three depositional sequences (DS), DS1 (base of Pragian to early Emsian); DS2 (early Emsian to mid Emsian); and DS3 (mid Emsian to mid Eifelian). These sequences were integrated into a peri-Gondwana relative sea-level curve, which was then compared with the Euramerican sea level curve of Johnson et al. (1985). The bioevents coincided with several sequence stratigraphic surfaces, representing variable limbs of the relative sea-level curve. On the other hand, their conspicuous coincidence with the switching intervals between the colder oligotrophic and warmer mesotrophic modes suggests that organic production linked to global climate was the primary control on biotic overturns, while sea-level fluctuations may have only amplified its effects.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10508 - Physical geography

Projekt

<a href="/cs/project/GA14-18183S" target="_blank" >GA14-18183S: Sekvenční stratigrafie devonských bioeventů - výkyvy mořské hladiny na přechodu od klimatického režimu greenhouse k icehouse</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2018

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Global and Planetary Change

ISSN

0921-8181

e-ISSN

1872-6364

Svazek periodika

160

Číslo periodika v rámci svazku

JAN

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

21

Strana od-do

75-95

Kód UT WoS článku

000424186200006

EID výsledku v databázi Scopus

2-s2.0-85034820295