High-Precision CA-ID-TIMS U-Pb Zircon Geochronology of Felsic Rocks in the Finlayson Lake VMS District, Yukon: Linking Paleozoic Basin-Scale Accumulation Rates to the Occurrence of Subseafloor Replacement-Style Mineralization

Author:

Manor Matthew J.1,Piercey Stephen J.1,Wall Corey J.23,Denisová Nikola1

Affiliation:

1. 1 Department of Earth Sciences, Memorial University of Newfoundland, St. John’s, Newfoundland A1B 3X5, Canada

2. 2 Isotope Geology Laboratory, Department of Geosciences, Boise State University, Boise, Idaho 83725, USA

3. 3 Pacific Centre for Isotopic and Geochemical Research, Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada

Abstract

Abstract Felsic igneous complexes and associated volcano-sedimentary rocks in continental back-arc environments host large-tonnage and/or high-grade volcanogenic massive sulfide (VMS) deposits. The emplacement mechanisms, style, and preservation of these deposits is thought to be partially dependent on depositional rates of the host lithofacies (i.e., discrete volcanic eruptions) relative to the setting of massive sulfide genesis on the seafloor as mounds and/or via subseafloor replacement of existing strata. The localization and occurrence of subseafloor replacement-style VMS deposits is therefore strongly influenced by the characteristics of the volcano-sedimentary facies in the hosting basin and the rates of their emplacement; the latter are poorly constrained in the literature due to the difficulty of obtaining high-precision dates that make this possible in Phanerozoic and older rocks. New high-resolution U-Pb geochronology and detailed regional stratigraphic investigation indicate that Devonian-Mississippian volcanic rocks and associated VMS mineralization in the Yukon-Tanana terrane in the Finlayson Lake district, Yukon, Canada, were erupted or emplaced during distinct time periods (ca. 363.3, 362.8, and 355.2 Ma) in two discrete submarine basins: the Kudz Ze Kayah formation and the Wolverine Lake group. The VMS deposits in both settings are contained within intrabasinal rocks that accumulated at rapid rates of ~350 to 2,000 m/m.y. over 0.6 to 1.4 m.y. Locally, these rates reach peak rates up to 7,500 m/m.y. in the Wolverine Lake group, which are interpreted to reflect facies deposition by mass transport complexes or turbidity currents. These new dates indicate that rapid accumulation of volcanic rocks in the back-arc basins was critical for localizing subseafloor replacement-style mineralization and the development of the Zn-enriched GP4F, Kudz Ze Kayah, and Wolverine VMS deposits. Rapid depositional processes observed in these deposits and their host basins are interpreted to have an important role in developing highly porous and permeable, water-saturated lithofacies that provide optimal conditions for enhancing zone refining processes and subsequent preservation of massive sulfide mineralization, which are key in the development of high-grade and large-tonnage VMS deposits. It is herein suggested that quantitative basin-scale accumulation rates, as a result of new U-Pb geochronological methods and increased precision combined with detailed stratigraphic and facies analysis, may provide important perspectives on the formation of continental back-arc basins and the localization of VMS deposits in other continental margin environments globally.

Publisher

Society of Economic Geologists, Inc.

Subject

Economic Geology,Geochemistry and Petrology,Geology,Geophysics

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3