{"title":"Titanium-oxide activity during the formation of gold-bearing quartz veins: evidence for closed system behavior","authors":"K. Pacak, J. Zacharias, M. Němec","doi":"10.3190/jgeosci.340","DOIUrl":null,"url":null,"abstract":"Titanium contents of both vein and magmatic quartz from five Bohemian gold deposits with known P–T history were used to calculate/discuss the titanium oxide activities (a TiO 2 ) of natural quartz formed in the absence of Ti-buffering phases at 250–550 °C and 0.1–4 kbar. Data suggest significant variations in a TiO 2 during vein quartz formation, due to variation of P, T and growth rate. Negative correlation between a TiO 2 and quartz formation temperature was documented for intrusion-related gold deposits, implying quartz precipitation under closed-system conditions (i.e., without substantial equilibration of the ascending fluid with surrounding rocks). We propose a relationship for quantifying disequilibrium quartz formation that can be readily applied to quartz with known P–T history. The relationship was tested on natural samples exhibiting both rapid and slow","PeriodicalId":15957,"journal":{"name":"Journal of Geosciences","volume":" ","pages":""},"PeriodicalIF":1.1000,"publicationDate":"2022-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Geosciences","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.3190/jgeosci.340","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
Titanium contents of both vein and magmatic quartz from five Bohemian gold deposits with known P–T history were used to calculate/discuss the titanium oxide activities (a TiO 2 ) of natural quartz formed in the absence of Ti-buffering phases at 250–550 °C and 0.1–4 kbar. Data suggest significant variations in a TiO 2 during vein quartz formation, due to variation of P, T and growth rate. Negative correlation between a TiO 2 and quartz formation temperature was documented for intrusion-related gold deposits, implying quartz precipitation under closed-system conditions (i.e., without substantial equilibration of the ascending fluid with surrounding rocks). We propose a relationship for quantifying disequilibrium quartz formation that can be readily applied to quartz with known P–T history. The relationship was tested on natural samples exhibiting both rapid and slow
期刊介绍:
The Journal of Geosciences is an international peer-reviewed journal published by the Czech Geological Society with support from the Czech Geological Survey. It accepts high-quality original research or review papers dealing with all aspects of the nature and origin of igneous and metamorphic rocks. The Journal focuses, mainly but not exclusively, on:
-Process-oriented regional studies of igneous and metamorphic complexes-
Research in structural geology and tectonics-
Igneous and metamorphic petrology-
Mineral chemistry and mineralogy-
Major- and trace-element geochemistry, isotope geochemistry-
Dating igneous activity and metamorphic events-
Experimental petrology and mineralogy-
Theoretical models of igneous and metamorphic processes-
Mineralizing processes and mineral deposits.
All the papers are written in English, even though they may be accompanied by an additional Czech abstract. Each contribution is a subject to peer review by at least two independent reviewers, typically at least one from abroad. The Journal appears 2 to 4 times a year. Formally it is divided in annual volumes, each of them including 4 issues.