{"title":"保加利亚Sakar - strandja地区Sakar单元最西端三叠纪变质沉积岩的变质作用","authors":"Tzvetomila Vladinova, M. Georgieva","doi":"10.31577/geolcarp.73.4.4","DOIUrl":null,"url":null,"abstract":": Metasedimentary sequence from the westernmost Sakar Unit (Klokotnitsa Village area), Sakar–Strandja Zone, comprises a variety of lithologies with Triassic protolith age. In the study area, the Sakar Unit is affected by low-grade metamorphism in the frame of the Maritsa dextral strike-slip shear zone and separates two first-order units of the Balkan orogenic system – the Rhodope massif and the Srednogorie Zone. We present the petrography, mineral chemical data, and thermodynamic modelling of metasediments for a better understanding of the protoliths origin and metamorphic evolution. The mineral assemblages in Triassic metasediments suggest sedimentary protoliths containing quartz, clay, and carbonate minerals (sandstones, clays, and limestones). The detrital minerals (quartz, albite, orthoclase and accessory phases – zircon, monazite, apatite) reveal potential granite source provenance. The dominance of phengite–chlorite association correlates with low temperature and water-saturated conditions. The Perple_X pseudosection, combined with modelled mineral assemblages and mineral chemistry isopleths of muscovite and chlorite, correspond to metamorphism in the range 275–330 °C and 3–4 kbar. The results correspond with a chlorite geothermometer. The thermodynamic modelling corroborates the petrographic observations and proves greenschist metamorphic conditions that affected the Triassic sedimentary cover of the westernmost Sakar Unit.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.0000,"publicationDate":"2022-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Metamorphism of the westernmost Triassic metasedimentary rocks in the Sakar unit, Sakar–Strandja zone, Bulgaria\",\"authors\":\"Tzvetomila Vladinova, M. Georgieva\",\"doi\":\"10.31577/geolcarp.73.4.4\",\"DOIUrl\":null,\"url\":null,\"abstract\":\": Metasedimentary sequence from the westernmost Sakar Unit (Klokotnitsa Village area), Sakar–Strandja Zone, comprises a variety of lithologies with Triassic protolith age. In the study area, the Sakar Unit is affected by low-grade metamorphism in the frame of the Maritsa dextral strike-slip shear zone and separates two first-order units of the Balkan orogenic system – the Rhodope massif and the Srednogorie Zone. We present the petrography, mineral chemical data, and thermodynamic modelling of metasediments for a better understanding of the protoliths origin and metamorphic evolution. The mineral assemblages in Triassic metasediments suggest sedimentary protoliths containing quartz, clay, and carbonate minerals (sandstones, clays, and limestones). The detrital minerals (quartz, albite, orthoclase and accessory phases – zircon, monazite, apatite) reveal potential granite source provenance. The dominance of phengite–chlorite association correlates with low temperature and water-saturated conditions. The Perple_X pseudosection, combined with modelled mineral assemblages and mineral chemistry isopleths of muscovite and chlorite, correspond to metamorphism in the range 275–330 °C and 3–4 kbar. The results correspond with a chlorite geothermometer. The thermodynamic modelling corroborates the petrographic observations and proves greenschist metamorphic conditions that affected the Triassic sedimentary cover of the westernmost Sakar Unit.\",\"PeriodicalId\":12545,\"journal\":{\"name\":\"Geologica Carpathica\",\"volume\":\" \",\"pages\":\"\"},\"PeriodicalIF\":1.0000,\"publicationDate\":\"2022-09-07\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Geologica Carpathica\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://doi.org/10.31577/geolcarp.73.4.4\",\"RegionNum\":4,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q4\",\"JCRName\":\"GEOSCIENCES, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Geologica Carpathica","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.31577/geolcarp.73.4.4","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
Metamorphism of the westernmost Triassic metasedimentary rocks in the Sakar unit, Sakar–Strandja zone, Bulgaria
: Metasedimentary sequence from the westernmost Sakar Unit (Klokotnitsa Village area), Sakar–Strandja Zone, comprises a variety of lithologies with Triassic protolith age. In the study area, the Sakar Unit is affected by low-grade metamorphism in the frame of the Maritsa dextral strike-slip shear zone and separates two first-order units of the Balkan orogenic system – the Rhodope massif and the Srednogorie Zone. We present the petrography, mineral chemical data, and thermodynamic modelling of metasediments for a better understanding of the protoliths origin and metamorphic evolution. The mineral assemblages in Triassic metasediments suggest sedimentary protoliths containing quartz, clay, and carbonate minerals (sandstones, clays, and limestones). The detrital minerals (quartz, albite, orthoclase and accessory phases – zircon, monazite, apatite) reveal potential granite source provenance. The dominance of phengite–chlorite association correlates with low temperature and water-saturated conditions. The Perple_X pseudosection, combined with modelled mineral assemblages and mineral chemistry isopleths of muscovite and chlorite, correspond to metamorphism in the range 275–330 °C and 3–4 kbar. The results correspond with a chlorite geothermometer. The thermodynamic modelling corroborates the petrographic observations and proves greenschist metamorphic conditions that affected the Triassic sedimentary cover of the westernmost Sakar Unit.
期刊介绍:
GEOLOGICA CARPATHICA covers a wide spectrum of geological disciplines including geodynamics, tectonics and structural geology, volcanology, stratigraphy, geochronology and isotopic geology, karstology, geochemistry, mineralogy, petrology, lithology and sedimentology, paleogeography, paleoecology, paleobiology and paleontology, paleomagnetism, magnetostratigraphy and other branches of applied geophysics, economic and environmental geology, experimental and theoretical geoscientific studies. Geologica Carpathica , with its 60 year old tradition, presents high-quality research papers devoted to all aspects not only of the Alpine-Carpathian-Balkanian geoscience but also with adjacent regions originated from the Mediterranean Tethys and its continental foreland. Geologica Carpathica is an Official Journal of the Carpathian-Balkan Geological Association.