Tectonic vs. anomalous magnetic fabrics in sedimentary rocks: a
case study from Barrandian, Czech Republic

a 2013

Tectonic vs. anomalous magnetic fabrics in sedimentary rocks: a case study from Barrandian, Czech Republic

ČERNÝ, Jan a Rostislav MELICHAR

Základní údaje

Originální název

Tectonic vs. anomalous magnetic fabrics in sedimentary rocks: a case study from Barrandian, Czech Republic

Autoři

ČERNÝ, Jan a Rostislav MELICHAR

Vydání

American Geoscience Union - meeting of the Americas, 14 – 17 May, 2013, Cancun, Mexico, 2013

Další údaje

Jazyk

angličtina

Typ výsledku

Konferenční abstrakt

Obor

10500 1.5. Earth and related environmental sciences

Stát vydavatele

Spojené státy

Utajení

není předmětem státního či obchodního tajemství

Odkazy

URL

Označené pro přenos do RIV

Ano

Kód RIV

RIV/00216224:14310/13:00069706

Organizační jednotka

Přírodovědecká fakulta

Klíčová slova česky

Anizotropie magnetické susceptibility; tektonika; barrandien

Klíčová slova anglicky

Anisotropy of Magnetis Susceptibility; Tectonics; Barrandian

Změněno: 13. 10. 2013 15:05, Mgr. Jan Černý, Ph.D.

Anotace

V originále

The study was focused on Ordovician sedimentary rocks and their anisotropy of magnetic susceptibility (AMS). The area under study is situated in the Prague Synform, Bohemian Massif, Czech Republic. Sedimentation in the basin began by Ordovician transgression and continued with siliciclastic rocks to Lower Silurian. The Upper Silurian is typical by carbonatic rocks as well as Devonian. The Silurian and Devonian sedimentary rocks are intensely folded and thrusted, while the Ordovician-rock deformation is not visible. The aim of the study was to find out whether the Ordovician rocks are actually un-deformed or were affected by strain by using AMS. Over 1500 samples were taken from 55 sites throughout dozen Ordovician formations. Temperature dependence of magnetic susceptibility was measured on the samples as well as AMS, which was compared to structural analysis of individual localities. In some specific cases, x-ray analysis or microscopic studies were done. Results and interpretations: 1) Analysis of temperature dependence of magnetic susceptibility showed that all Ordovician formations are controlled by paramagnetic minerals. 2) In majority sites normal sedimentary or strain fabrics were recognized. In these sites structural studies were mostly done but there were also found inverse and intermediate fabrics. 3) Inverse fabrics found in 4 sites were caused by fibrous ankerite. Fibers were grown perpendicularly to the bedding plane in the fibrous microveins and cone-in-cone textures. The maximum susceptibility direction is parallel to crystallographic c-axis of ankerite in the samples. 4) Intermediate fabrics or their relics were exclusively linked to all localities in two basal Ordovician formations. In this case, we cannot speculate about simple combination of normal and inverse fabrics but about autoregulatory diagenetic processes.

Citovat

ČERNÝ, Jan a Rostislav MELICHAR. Tectonic vs. anomalous magnetic fabrics in sedimentary rocks: a case study from Barrandian, Czech Republic. In American Geoscience Union - meeting of the Americas, 14 – 17 May, 2013, Cancun, Mexico. 2013.

@proceedings{1125556,
   author = {Černý, Jan and Melichar, Rostislav},
   booktitle = {American Geoscience Union - meeting of the Americas, 14 – 17 May, 2013, Cancun, Mexico},
   keywords = {Anisotropy of Magnetis Susceptibility; Tectonics; Barrandian},
   language = {eng},
   title = {Tectonic vs. anomalous magnetic fabrics in sedimentary rocks: a case study from Barrandian, Czech Republic},
   url = {http://moa.agu.org/2013/files/2013/05/newMOA-Program-Book-for-Web.pdf},
   year = {2013}
}

TY  - CONF
ID  - 1125556
AU  - Černý, Jan - Melichar, Rostislav
PY  - 2013
TI  - Tectonic vs. anomalous magnetic fabrics in sedimentary rocks: a case study from Barrandian, Czech Republic
KW  - Anisotropy of Magnetis Susceptibility
KW  - Tectonics
KW  - Barrandian
UR  - http://moa.agu.org/2013/files/2013/05/newMOA-Program-Book-for-Web.pdf
N2  - The study was focused on Ordovician sedimentary rocks and their anisotropy of magnetic susceptibility (AMS). The area under study is situated in the Prague Synform, Bohemian Massif, Czech Republic. Sedimentation in the basin began by Ordovician transgression and continued with siliciclastic rocks to Lower Silurian. The Upper Silurian is typical by carbonatic rocks as well as Devonian. The Silurian and Devonian sedimentary rocks are intensely folded and thrusted, while the Ordovician-rock deformation is not visible. The aim of the study was to find out whether the Ordovician rocks are actually un-deformed or were affected by strain by using AMS. Over 1500 samples were taken from 55 sites throughout dozen Ordovician formations. Temperature dependence of magnetic susceptibility was measured on the samples as well as AMS, which was compared to structural analysis of individual localities. In some specific cases, x-ray analysis or microscopic studies were done. Results and interpretations: 1) Analysis of temperature dependence of magnetic susceptibility showed that all Ordovician formations are controlled by paramagnetic minerals. 2) In majority sites normal sedimentary or strain fabrics were recognized. In these sites structural studies were mostly done but there were also found inverse and intermediate fabrics. 3) Inverse fabrics found in 4 sites were caused by fibrous ankerite. Fibers were grown perpendicularly to the bedding plane in the fibrous microveins and cone-in-cone textures. The maximum susceptibility direction is parallel to crystallographic c-axis of ankerite in the samples. 4) Intermediate fabrics or their relics were exclusively linked to all localities in two basal Ordovician formations. In this case, we cannot speculate about simple combination of normal and inverse fabrics but about autoregulatory diagenetic processes.
ER  -

ČERNÝ, Jan a Rostislav MELICHAR. Tectonic vs. anomalous magnetic fabrics in sedimentary rocks: a case study from Barrandian, Czech Republic. In \textit{American Geoscience Union - meeting of the Americas, 14 – 17 May, 2013, Cancun, Mexico}. 2013.

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