Common high-pressure metamorphic history of eclogite lenses and sorrounding metasediments

A case study of calc-silicate reaction zones (Erzgebirge, Germany)

Juliane Gross, Michael Burchard, Hans Peter Schertl, Walter V. Maresch

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

The Erzgebirge dome in the Central European Variscides is a stack of crustal slices including some high- and ultrahigh-pressure rocks related to continent-continent collision. One such slice is the Mica-Schist/ Eclogite Unit, in which the predominantly metasedimentary country rocks appear to record maximum metamorphic pressures of at most 11-13 kbar, whereas volumetrically minor eclogite lenses within the unit indicate pressures up to 27 kbar. In the present study, the P-T evolution of rocks found in calc-silicate reaction zones between eclogite and country rock marble near the locality Stümpelfelsen, a crag composed of eclogite near the village of Hammerunterwiesenthal, has been established via conventional geothermobarometry. A metasomatic marble-eclogite interchange can be documented for the earliest stages of prograde metamorphism. Significant amounts of fluorine infiltrated the metabasic rocks from the marbles, leading to fluorine-bearing amphibole as well as phengite, and even fluorine-rich growth zones in garnet with 0.62 wt.% F and 1.2 wt.% OH. This appears to be the first description of a F-bearing member of an almandine-grossular solid solution poor in andradite component. The P-T path of the eclogite marble reaction zone reaches a maximum pressure of 26 kbar at 520-640 °C, just below the quartz-coesite transition. The exhumation path can be traced to 10 kbar and 450-600 °C, where it is then coincident with the published P-T paths of the mica schists and orthogneisses of the Mica-Schist/Eclogite Unit. This study indicates that the Stümpelfelsen eclogite lens and the surrounding metasedimentary country rock of the area must share a common high-pressure metamorphic history. The critical question arising for future studies is how much of the Mica-Schist/Eclogite Unit has actually "travelled the high-pressure eclogite route", and how much of it was never subducted to pressures greater than 11-13 kbar.

Original languageEnglish (US)
Pages (from-to)757-775
Number of pages19
JournalEuropean Journal of Mineralogy
Volume20
Issue number5
DOIs
StatePublished - Sep 1 2008
Externally publishedYes

Fingerprint

Silicates
metasediment
eclogite
Lenses
silicate
Calcium Carbonate
Rocks
Fluorine
Bearings (structural)
history
marble
mica
schist
fluorine
country rock
Amphibole Asbestos
Rock pressure
metasedimentary rock
Quartz
Garnets

All Science Journal Classification (ASJC) codes

  • Geochemistry and Petrology

Cite this

@article{2ea80bb5ee5846aca23244d273ef8ed4,
title = "Common high-pressure metamorphic history of eclogite lenses and sorrounding metasediments: A case study of calc-silicate reaction zones (Erzgebirge, Germany)",
abstract = "The Erzgebirge dome in the Central European Variscides is a stack of crustal slices including some high- and ultrahigh-pressure rocks related to continent-continent collision. One such slice is the Mica-Schist/ Eclogite Unit, in which the predominantly metasedimentary country rocks appear to record maximum metamorphic pressures of at most 11-13 kbar, whereas volumetrically minor eclogite lenses within the unit indicate pressures up to 27 kbar. In the present study, the P-T evolution of rocks found in calc-silicate reaction zones between eclogite and country rock marble near the locality St{\"u}mpelfelsen, a crag composed of eclogite near the village of Hammerunterwiesenthal, has been established via conventional geothermobarometry. A metasomatic marble-eclogite interchange can be documented for the earliest stages of prograde metamorphism. Significant amounts of fluorine infiltrated the metabasic rocks from the marbles, leading to fluorine-bearing amphibole as well as phengite, and even fluorine-rich growth zones in garnet with 0.62 wt.{\%} F and 1.2 wt.{\%} OH. This appears to be the first description of a F-bearing member of an almandine-grossular solid solution poor in andradite component. The P-T path of the eclogite marble reaction zone reaches a maximum pressure of 26 kbar at 520-640 °C, just below the quartz-coesite transition. The exhumation path can be traced to 10 kbar and 450-600 °C, where it is then coincident with the published P-T paths of the mica schists and orthogneisses of the Mica-Schist/Eclogite Unit. This study indicates that the St{\"u}mpelfelsen eclogite lens and the surrounding metasedimentary country rock of the area must share a common high-pressure metamorphic history. The critical question arising for future studies is how much of the Mica-Schist/Eclogite Unit has actually {"}travelled the high-pressure eclogite route{"}, and how much of it was never subducted to pressures greater than 11-13 kbar.",
author = "Juliane Gross and Michael Burchard and Schertl, {Hans Peter} and Maresch, {Walter V.}",
year = "2008",
month = "9",
day = "1",
doi = "10.1127/0935-1221/2008/0020-1861",
language = "English (US)",
volume = "20",
pages = "757--775",
journal = "European Journal of Mineralogy",
issn = "0935-1221",
publisher = "E. Schweizerbart'sche Verlagsbuchhandlung",
number = "5",

}

Common high-pressure metamorphic history of eclogite lenses and sorrounding metasediments : A case study of calc-silicate reaction zones (Erzgebirge, Germany). / Gross, Juliane; Burchard, Michael; Schertl, Hans Peter; Maresch, Walter V.

In: European Journal of Mineralogy, Vol. 20, No. 5, 01.09.2008, p. 757-775.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Common high-pressure metamorphic history of eclogite lenses and sorrounding metasediments

T2 - A case study of calc-silicate reaction zones (Erzgebirge, Germany)

AU - Gross, Juliane

AU - Burchard, Michael

AU - Schertl, Hans Peter

AU - Maresch, Walter V.

PY - 2008/9/1

Y1 - 2008/9/1

N2 - The Erzgebirge dome in the Central European Variscides is a stack of crustal slices including some high- and ultrahigh-pressure rocks related to continent-continent collision. One such slice is the Mica-Schist/ Eclogite Unit, in which the predominantly metasedimentary country rocks appear to record maximum metamorphic pressures of at most 11-13 kbar, whereas volumetrically minor eclogite lenses within the unit indicate pressures up to 27 kbar. In the present study, the P-T evolution of rocks found in calc-silicate reaction zones between eclogite and country rock marble near the locality Stümpelfelsen, a crag composed of eclogite near the village of Hammerunterwiesenthal, has been established via conventional geothermobarometry. A metasomatic marble-eclogite interchange can be documented for the earliest stages of prograde metamorphism. Significant amounts of fluorine infiltrated the metabasic rocks from the marbles, leading to fluorine-bearing amphibole as well as phengite, and even fluorine-rich growth zones in garnet with 0.62 wt.% F and 1.2 wt.% OH. This appears to be the first description of a F-bearing member of an almandine-grossular solid solution poor in andradite component. The P-T path of the eclogite marble reaction zone reaches a maximum pressure of 26 kbar at 520-640 °C, just below the quartz-coesite transition. The exhumation path can be traced to 10 kbar and 450-600 °C, where it is then coincident with the published P-T paths of the mica schists and orthogneisses of the Mica-Schist/Eclogite Unit. This study indicates that the Stümpelfelsen eclogite lens and the surrounding metasedimentary country rock of the area must share a common high-pressure metamorphic history. The critical question arising for future studies is how much of the Mica-Schist/Eclogite Unit has actually "travelled the high-pressure eclogite route", and how much of it was never subducted to pressures greater than 11-13 kbar.

AB - The Erzgebirge dome in the Central European Variscides is a stack of crustal slices including some high- and ultrahigh-pressure rocks related to continent-continent collision. One such slice is the Mica-Schist/ Eclogite Unit, in which the predominantly metasedimentary country rocks appear to record maximum metamorphic pressures of at most 11-13 kbar, whereas volumetrically minor eclogite lenses within the unit indicate pressures up to 27 kbar. In the present study, the P-T evolution of rocks found in calc-silicate reaction zones between eclogite and country rock marble near the locality Stümpelfelsen, a crag composed of eclogite near the village of Hammerunterwiesenthal, has been established via conventional geothermobarometry. A metasomatic marble-eclogite interchange can be documented for the earliest stages of prograde metamorphism. Significant amounts of fluorine infiltrated the metabasic rocks from the marbles, leading to fluorine-bearing amphibole as well as phengite, and even fluorine-rich growth zones in garnet with 0.62 wt.% F and 1.2 wt.% OH. This appears to be the first description of a F-bearing member of an almandine-grossular solid solution poor in andradite component. The P-T path of the eclogite marble reaction zone reaches a maximum pressure of 26 kbar at 520-640 °C, just below the quartz-coesite transition. The exhumation path can be traced to 10 kbar and 450-600 °C, where it is then coincident with the published P-T paths of the mica schists and orthogneisses of the Mica-Schist/Eclogite Unit. This study indicates that the Stümpelfelsen eclogite lens and the surrounding metasedimentary country rock of the area must share a common high-pressure metamorphic history. The critical question arising for future studies is how much of the Mica-Schist/Eclogite Unit has actually "travelled the high-pressure eclogite route", and how much of it was never subducted to pressures greater than 11-13 kbar.

UR - http://www.scopus.com/inward/record.url?scp=56849126593&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=56849126593&partnerID=8YFLogxK

U2 - 10.1127/0935-1221/2008/0020-1861

DO - 10.1127/0935-1221/2008/0020-1861

M3 - Article

VL - 20

SP - 757

EP - 775

JO - European Journal of Mineralogy

JF - European Journal of Mineralogy

SN - 0935-1221

IS - 5

ER -