Variscan pegmatite and K-Ar and Ar/Ar dating from basement rocks of the Zemplin Unit, Western Carpathians

Shah Wali Faryad, K. Balogh

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

K-Ar age data from minerals (white mica, amphibole, biotite, and feldspar) in metamorphic rocks and pegmatite indicate Variscan metamorphic and magmatic events in the Zemplin Unit. The rocks hosting these minerals are amphibolite, gneiss, micaschist, and pegmatite. This is the first report on the occurrence of pegmatite from this unit, which indicates a Variscan age (≥ 307.9 ± 12.0 Ma) for igneous activity. Amphibolite facies metamorphism is dated based on K-Ar measurement of amphibole from amphibolite that gave age of 338 Ma. K-Ar ages of muscovite and of some amphiboles depend on the degree of mylonitization of the host micaschists and amphibolite, and range from 284.8 ± Ma to 211 ± 9 Ma. Ar/Ar spectrum on a white mica of 227 Ma K-Ar age yielded a ca. 300 Ma plateau-like age and indicates a younger, most likely Alpine overprint. Cretaceous ages of 105 ± 4.2 Ma and 126.6 ± 5.2 Ma were obtained from plagioclase and from white mica concentrate (<2μm fraction) from strongly mylonitized amphibolite. This suggests that most K/Ar ages between the Variscan and Alpine orogenies (284-211 Ma) are geologically meaningless mixed values. The data support the interpretation of Variscan amphibolite facies metamorphism > 338 Ma with subsequent magmatism > 307.9 Ma) followed by Alpine overprint (126-105 Ma).

Original languageEnglish
Pages (from-to)193-205
Number of pages13
JournalActa Geologica Hungarica
Volume45
Issue number2
DOIs
Publication statusPublished - 2002

Fingerprint

pegmatite
basement rock
Hercynian orogeny
amphibolite
mica
amphibole
mylonitization
mineral
dating
amphibolite facies
muscovite
gneiss
metamorphic rock
feldspar
biotite
magmatism
plagioclase
metamorphism
plateau
Cretaceous

Keywords

  • Amphibolite facies metamorphism
  • K-Ar and Ar/Ar dating
  • Pegmatite
  • Western Carpathians
  • Zemplin Unit

ASJC Scopus subject areas

  • Geology

Cite this

Variscan pegmatite and K-Ar and Ar/Ar dating from basement rocks of the Zemplin Unit, Western Carpathians. / Faryad, Shah Wali; Balogh, K.

In: Acta Geologica Hungarica, Vol. 45, No. 2, 2002, p. 193-205.

Research output: Contribution to journalArticle

@article{0ae50db378d34a5d8166ee4f0defceb2,
title = "Variscan pegmatite and K-Ar and Ar/Ar dating from basement rocks of the Zemplin Unit, Western Carpathians",
abstract = "K-Ar age data from minerals (white mica, amphibole, biotite, and feldspar) in metamorphic rocks and pegmatite indicate Variscan metamorphic and magmatic events in the Zemplin Unit. The rocks hosting these minerals are amphibolite, gneiss, micaschist, and pegmatite. This is the first report on the occurrence of pegmatite from this unit, which indicates a Variscan age (≥ 307.9 ± 12.0 Ma) for igneous activity. Amphibolite facies metamorphism is dated based on K-Ar measurement of amphibole from amphibolite that gave age of 338 Ma. K-Ar ages of muscovite and of some amphiboles depend on the degree of mylonitization of the host micaschists and amphibolite, and range from 284.8 ± Ma to 211 ± 9 Ma. Ar/Ar spectrum on a white mica of 227 Ma K-Ar age yielded a ca. 300 Ma plateau-like age and indicates a younger, most likely Alpine overprint. Cretaceous ages of 105 ± 4.2 Ma and 126.6 ± 5.2 Ma were obtained from plagioclase and from white mica concentrate (<2μm fraction) from strongly mylonitized amphibolite. This suggests that most K/Ar ages between the Variscan and Alpine orogenies (284-211 Ma) are geologically meaningless mixed values. The data support the interpretation of Variscan amphibolite facies metamorphism > 338 Ma with subsequent magmatism > 307.9 Ma) followed by Alpine overprint (126-105 Ma).",
keywords = "Amphibolite facies metamorphism, K-Ar and Ar/Ar dating, Pegmatite, Western Carpathians, Zemplin Unit",
author = "Faryad, {Shah Wali} and K. Balogh",
year = "2002",
doi = "10.1556/AGeol.45.2002.2.4",
language = "English",
volume = "45",
pages = "193--205",
journal = "Central European Geology",
issn = "1788-2281",
publisher = "Akademiai Kiado",
number = "2",

}

TY - JOUR

T1 - Variscan pegmatite and K-Ar and Ar/Ar dating from basement rocks of the Zemplin Unit, Western Carpathians

AU - Faryad, Shah Wali

AU - Balogh, K.

PY - 2002

Y1 - 2002

N2 - K-Ar age data from minerals (white mica, amphibole, biotite, and feldspar) in metamorphic rocks and pegmatite indicate Variscan metamorphic and magmatic events in the Zemplin Unit. The rocks hosting these minerals are amphibolite, gneiss, micaschist, and pegmatite. This is the first report on the occurrence of pegmatite from this unit, which indicates a Variscan age (≥ 307.9 ± 12.0 Ma) for igneous activity. Amphibolite facies metamorphism is dated based on K-Ar measurement of amphibole from amphibolite that gave age of 338 Ma. K-Ar ages of muscovite and of some amphiboles depend on the degree of mylonitization of the host micaschists and amphibolite, and range from 284.8 ± Ma to 211 ± 9 Ma. Ar/Ar spectrum on a white mica of 227 Ma K-Ar age yielded a ca. 300 Ma plateau-like age and indicates a younger, most likely Alpine overprint. Cretaceous ages of 105 ± 4.2 Ma and 126.6 ± 5.2 Ma were obtained from plagioclase and from white mica concentrate (<2μm fraction) from strongly mylonitized amphibolite. This suggests that most K/Ar ages between the Variscan and Alpine orogenies (284-211 Ma) are geologically meaningless mixed values. The data support the interpretation of Variscan amphibolite facies metamorphism > 338 Ma with subsequent magmatism > 307.9 Ma) followed by Alpine overprint (126-105 Ma).

AB - K-Ar age data from minerals (white mica, amphibole, biotite, and feldspar) in metamorphic rocks and pegmatite indicate Variscan metamorphic and magmatic events in the Zemplin Unit. The rocks hosting these minerals are amphibolite, gneiss, micaschist, and pegmatite. This is the first report on the occurrence of pegmatite from this unit, which indicates a Variscan age (≥ 307.9 ± 12.0 Ma) for igneous activity. Amphibolite facies metamorphism is dated based on K-Ar measurement of amphibole from amphibolite that gave age of 338 Ma. K-Ar ages of muscovite and of some amphiboles depend on the degree of mylonitization of the host micaschists and amphibolite, and range from 284.8 ± Ma to 211 ± 9 Ma. Ar/Ar spectrum on a white mica of 227 Ma K-Ar age yielded a ca. 300 Ma plateau-like age and indicates a younger, most likely Alpine overprint. Cretaceous ages of 105 ± 4.2 Ma and 126.6 ± 5.2 Ma were obtained from plagioclase and from white mica concentrate (<2μm fraction) from strongly mylonitized amphibolite. This suggests that most K/Ar ages between the Variscan and Alpine orogenies (284-211 Ma) are geologically meaningless mixed values. The data support the interpretation of Variscan amphibolite facies metamorphism > 338 Ma with subsequent magmatism > 307.9 Ma) followed by Alpine overprint (126-105 Ma).

KW - Amphibolite facies metamorphism

KW - K-Ar and Ar/Ar dating

KW - Pegmatite

KW - Western Carpathians

KW - Zemplin Unit

UR - http://www.scopus.com/inward/record.url?scp=0142156512&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0142156512&partnerID=8YFLogxK

U2 - 10.1556/AGeol.45.2002.2.4

DO - 10.1556/AGeol.45.2002.2.4

M3 - Article

VL - 45

SP - 193

EP - 205

JO - Central European Geology

JF - Central European Geology

SN - 1788-2281

IS - 2

ER -