{"title":"Mineral Composition and Stratigraphic Position of Interior Jewelry Ammonites from the Middle Aptian of the Republic of North Ossetia-Alania","authors":"E. Yu. Baraboshkin, D. A. Petrochenkov","doi":"10.3103/s0145875224700182","DOIUrl":null,"url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The stratigraphic position and mineral composition of ammonite shells of interior and jewelry quality from the Republic of North Ossetia-Alania have been studied for the first time. Ammonites were collected from the middle reaches of the Urukh River and originated from middle Aptian sediments accumulated in anoxic environments. The set of ammonite studies included determination of microhardness, density, luminescence; optical–petrographic analysis; quantitative determination of chemical and mineral composition; and electron probe studies. Ammonites consist mainly of calcite, pyrite, and aragonite. The walls and septa of the shells retained the original aragonite composition. The residential and destroyed hydrostatic chambers of the shells are composed of marl. Micron inclusions of ankerite and apatite have been found from accessory minerals. Sr and Ni have been identified as impurities. The mineralization of the shells began with the formation of pyrite layers. The mineral composition of the ammonites is calcite–pyrite.</p>","PeriodicalId":44391,"journal":{"name":"Moscow University Geology Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3000,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Moscow University Geology Bulletin","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.3103/s0145875224700182","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"GEOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
The stratigraphic position and mineral composition of ammonite shells of interior and jewelry quality from the Republic of North Ossetia-Alania have been studied for the first time. Ammonites were collected from the middle reaches of the Urukh River and originated from middle Aptian sediments accumulated in anoxic environments. The set of ammonite studies included determination of microhardness, density, luminescence; optical–petrographic analysis; quantitative determination of chemical and mineral composition; and electron probe studies. Ammonites consist mainly of calcite, pyrite, and aragonite. The walls and septa of the shells retained the original aragonite composition. The residential and destroyed hydrostatic chambers of the shells are composed of marl. Micron inclusions of ankerite and apatite have been found from accessory minerals. Sr and Ni have been identified as impurities. The mineralization of the shells began with the formation of pyrite layers. The mineral composition of the ammonites is calcite–pyrite.
期刊介绍:
Moscow University Geology Bulletin is the journal that mainly publishes scientific articles, short reports of graduate students, and reviews. Publications made by the members of the Faculty of Geology of the Moscow State University and their collaborators are published. Publications encompass all branches of geology.