DOCSLIB.ORG

Tectonic History of the South Tannuol Fault Zone (Tuva Region of the Northern Central Asian Orogenic Belt, Russia): Constraints from Multi-Method Geochronology

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Tectonic History of the South Tannuol Fault Zone (Tuva Region of the Northern Central Asian Orogenic Belt, Russia): Constraints from Multi-Method Geochronology minerals Article Tectonic History of the South Tannuol Fault Zone (Tuva Region of the Northern Central Asian Orogenic Belt, Russia): Constraints from Multi-Method Geochronology Evgeny Vetrov 1,*, Johan De Grave 2, Natalia Vetrova 1, Fedor Zhimulev 1, Simon Nachtergaele 2 , Gerben Van Ranst 2 and Polina Mikhailova 3 1 Sobolev Institute of Geology and Mineralogy, Siberian Branch Russian Academy of Sciences, Koptuga ave. 3, 630090 Novosibirsk, Russia; [email protected] (N.V.); [email protected] (F.Z.) 2 Department of Geology, Ghent University, Krijgslaan 281.S8, WE13, 9000 Ghent, Belgium; [email protected] (J.D.G.); [email protected] (S.N.); [email protected] (G.V.R.) 3 Siberian Research Institute of Geology, Geophysics and Mineral Resources, Krasniy ave. 35, 630099 Novosibirsk, Russia; [email protected] * Correspondence: [email protected] or [email protected]; Tel.: +7-913-770-75-10 Received: 12 November 2019; Accepted: 6 January 2020; Published: 9 January 2020 Abstract: In this study, we present zircon U/Pb, plagioclase and K-feldspar 40Ar/39Ar and apatite fission track (AFT) data along the South Tannuol Fault Zone (STFZ). Integrating geochronology and multi-method thermochronology places constraints on the formation and subsequent reactivation of the STFZ. Cambrian (~510 Ma) zircon U/Pb ages obtained for felsic volcanic rocks date the final stage of STFZ basement formation. Ordovician (~460–450 Ma) zircon U/Pb ages were obtained for felsic rocks along the structure, dating their emplacement and marking post-formational local magmatic activity along the STFZ. 40Ar/39Ar stepwise heating plateau-ages (~410–400 Ma, ~365 and ~340 Ma) reveal Early Devonian and Late Devonian–Mississippian intrusion and/or post-magmatic cooling episodes of mafic rocks in the basement. Permian (~290 Ma) zircon U/Pb age of mafic rocks documents for the first time Permian magmatism in the study area creating prerequisites for revising the spread of Permian large igneous provinces of Central Asia. The AFT dating and Thermal history modeling based on the AFT data reveals two intracontinental tectonic reactivation episodes of the STFZ: (1) a period of Cretaceous–Eocene (~100–40 Ma) reactivation and (2) the late Neogene (from ~10 Ma onwards) impulse after a period of tectonic stability during the Eocene–Miocene (~40–10 Ma). Keywords: zircon U/Pb dating; 40Ar/39Ar dating; AFT thermochronology; Tuva Region 1. Introduction The South Tannuol Fault Zone (STFZ) is situated in the Tuva Region (Russian Federation) of the Altay–Sayan Fold Belt (ASFB) in the northwestern (Siberian) part of the Central Asia Orogenic Belt (CAOB) (Figure1). The STFZ is a sub-latitudinal system of normal faults acted in the same mode during its formation and reactivation stages. The shear component is not excluded; however, the normal fault component keeps principal. The STFZ is characterized by steep fall of the fault blocks and the vertical displacement amplitude along the largest fault segments from 300 to 3000 m. It controls the tectonic evolution of the Tannuol Mountain Range, the most prominent topographic feature with an altitude of up to 2400 m in the Tuva–Mongolia border zone (800–1000 m). The Tannuol Range is composed mainly of Paleozoic volcanic rocks of island arc affinity, intruded by various plutons of different ages and compositions (Figure2). The volcanic rocks are deformed into intricate linear folds Minerals 2020, 10, 56; doi:10.3390/min10010056 www.mdpi.com/journal/minerals Minerals 2019, 9, x FOR PEER REVIEW 2 of 22 Minerals 2020, 10, 56 2 of 22 Tannuol Range is composed mainly of Paleozoic volcanic rocks of island arc affinity, intruded by various plutons of different ages and compositions (Figure 2). The volcanic rocks are deformed into with sub-latitudinal strike of the fold axes, conform to the strike of the fault system. Intrusive rocks intricate linear folds with sub-latitudinal strike of the fold axes, conform to the strike of the fault (gabbros and granitoids) often form linear bodies elongated along strike of the STFZ. This indicates the system. Intrusive rocks (gabbros and granitoids) often form linear bodies elongated along strike of STFZ controls the emplacement of the Paleozoic igneous basement rocks of the Tannuol Range and the STFZ. This indicates the STFZ controls the emplacement of the Paleozoic igneous basement rocks controls their deformation during subsequent reactivation phases. of the Tannuol Range and controls their deformation during subsequent reactivation phases. Figure 1. Digital elevation model (SRTM data) of the northern part of the Central Asian Orogenic Belt (CAOB).(CAOB). OurOur studystudy areaarea ofof thethe SouthSouth TannuolTannuol FaultFault ZoneZone (STFZ)(STFZ) is is indicated indicated byby thethe black black box. box. The PaleozoicPaleozoic igneous igneous basement basement rocks rocks exposed exposed along along the STFZ the provideSTFZ provide insights intoinsights the formation into the andformation subsequent and subsequent reactivation reactivation episodes of episodes the STFZ. of Itthe is hypothesizedSTFZ. It is hypothesized that in the studiedthat in the part studied of the CAOBpart of (e.g.,the CAOB Kuznetsk (e.g., Alatau, Kuznetsk West Alatau, Sayan, GornyWest Sayan, Altay), theseGorny Paleozoic Altay), these stages Paleozoic are associated stages with are tectonicassociated events with at tectonic the margins events of theat the Paleo margins Asian Oceanof the (PAO) Paleo basinsAsian [1Ocean–4]. In (PAO) addition, basins the Paleozoic[1–4]. In basementaddition, the rocks Paleozoic record evidence basement of rocks subsequent record deformationevidence of andsubsequent exhumation deformation throughout and the exhumation Mesozoic andthroughout Cenozoic. the These Mesozoic same and basement Cenozoic. rocks These also record same Meso-Cenozoicbasement rocks deformation also record andMeso-Cenozoic exhumation events.deformation The present and exhumation mountainous events. morphology The present of the mountainous Tuva Region ismorphology considered toof havethe Tuva formed Region during is reactivationconsidered to of have inherited formed structures, during reactivation such as the STFZ.of inherited structures, such as the STFZ. Despite its its structural structural importance importance to the to thetectonic tectonic evolution evolution of theof Altay–Sayan, the Altay–Sayan, the STFZ the remains STFZ remainspoorly resolved poorly resolvedby modern by geochronological modern geochronological and thermochronological and thermochronological techniques. techniques. Only in the Only last indecade the last modern decade geochronology modern geochronology data have been data obta haveined been for obtainedthe Paleozoic for therocks Paleozoic [5–7]. Previously, rocks [5–7 a]. Previously,general model a general of the Altay–Sayan model of the fold Altay–Sayan belt formation fold belt and formation evolution and was evolution proposed was for the proposed Paleozoic for thehistory Paleozoic and tectonic history events and tectonicalong the events STFZ [1–4]. along Meso-Cenozoic the STFZ [1–4]. de Meso-Cenozoicformation and exhumation deformation events and exhumationin the study area events were in decrypted the study areaonly wereby lithological decrypted and only stratigraphic by lithological dataand of the stratigraphic Jurassic [8–11] data and of theCenozoic Jurassic [12–15] [8–11] sedimentary and Cenozoic basins [12–15 of] sedimentaryTuva and Mongolia. basins of Therefore, Tuva and Mongolia. dating accessory Therefore, and dating rock- accessoryforming minerals and rock-forming from the Paleozoic minerals fromigneous the baseme Paleozoicnt rocks igneous along basement the STFZ rocks using along high-temperature the STFZ using high-temperatureand low-temperature and methods low-temperature is necessary methods to obtain is necessarynew constraints to obtain on tectonic new constraints history of on the tectonic STFZ. historyInterpretation of the STFZ. of these Interpretation data according of these to datatectonic according evolution to tectonic of the evolutionstudy part of of the the study CAOB part allows of the CAOBtesting allowsand clarification testing and of clarification the established of the hypothesis. established hypothesis. Minerals 2020, 10, 56 3 of 22 Minerals 2019, 9, x FOR PEER REVIEW 3 of 22 Figure 2. (a) Simplified geological map of the South Tannuol Fault Zone (STFZ) (based on [5]) with Figure 2. (a) Simplified geological map of the South Tannuol Fault Zone (STFZ) (based on [5]) with sample positions indicated; (b) digital relief model (SRTM data, Mercator projection—WGS84) of the sample positions indicated; (b) digital relief model (SRTM data, Mercator projection—WGS84) of STFZ with indication of main structural features, basins and mountain ranges. Sample sites are the STFZ with indication of main structural features, basins and mountain ranges. Sample sites are indicated, see Table 1 for details. indicated, see Table 1 for details. The aim of this study is to reconstruct the chronology of formation, reactivation and deformation The aim of this study is to reconstruct the chronology of formation, reactivation and deformation of the area within the STFZ. Zircon U/Pb, plagioclase 40Ar/39Ar and K-feldspar 40Ar/39Ar dating of of the area within the STFZ. Zircon U/Pb, plagioclase 40Ar/39Ar and K-feldspar 40Ar/39Ar dating of igneous rocks along the STFZ allows identifying formation and activation stages and apatite fission igneoustrack thermochronology rocks along the
Load more

Recommended publications
  • Comparison of Detrital Zircon U-Pb and Muscovite 40Ar/39Ar Ages in the Yangtze Sediment: Implications for Provenance Studies
    minerals Article Comparison of Detrital Zircon U-Pb and Muscovite 40Ar/39Ar Ages in the Yangtze Sediment: Implications for Provenance Studies Xilin Sun 1,2,* , Klaudia F. Kuiper 2, Yuntao Tian 1, Chang’an Li 3, Zengjie Zhang 1 and Jan R. Wijbrans 2 1 School of Earth Sciences and Engineering, Sun Yat-sen University, Guangzhou 510275, China; [email protected] (Y.T.); [email protected] (Z.Z.) 2 Department of Earth Sciences, Cluster Geology and Geochemistry, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, the Netherlands; [email protected] (K.F.K.); [email protected] (J.R.W.) 3 School of Geography and Information Engineering, China University of Geosciences, Wuhan 430074, China; [email protected] * Correspondence: [email protected] Received: 30 June 2020; Accepted: 17 July 2020; Published: 20 July 2020 Abstract: Detrital zircon U-Pb and muscovite 40Ar/39Ar dating are useful tools for investigating sediment provenance and regional tectonic histories. However, the two types of data from same sample do not necessarily give consistent results. Here, we compare published detrital muscovite 40Ar/39Ar and zircon U-Pb ages of modern sands from the Yangtze River to reveal potential factors controlling differences in their provenance age signals. Detrital muscovite 40Ar/39Ar ages of the Major tributaries and Main trunk suggest that the Dadu River is a dominant sediment contributor to the lower Yangtze. However, detrital zircon data suggest that the Yalong, Dadu, and Min rivers are the most important sediment suppliers. This difference could be caused by combined effects of lower reaches dilution, laser spot location on zircons and difference in closure temperature and durability between muscovite and zircon.
    [Show full text]
  • Apatite Thermochronology in Modern Geology
    Downloaded from http://sp.lyellcollection.org/ by guest on September 25, 2021 Apatite thermochronology in modern geology F. LISKER1*, B. VENTURA1 & U. A. GLASMACHER2 1Fachbereich Geowissenschaften, Universita¨t Bremen, PF 330440, 28334 Bremen, Germany 2Institut fu¨r Geowissenschaften, Ruprecht-Karls-Universita¨t Heidelberg, Im Neuenheimer Feld 234, 69120 Heidelberg, Germany *Corresponding author (e-mail: fl[email protected]) Abstract: Fission-track and (U–Th–Sm)/He thermochronology on apatites are radiometric dating methods that refer to thermal histories of rocks within the temperature range of 408–125 8C. Their introduction into geological research contributed to the development of new concepts to interpreting time-temperature constraints and substantially improved the understanding of cooling processes within the uppermost crust. Present geological applications of apatite thermochronological methods include absolute dating of rocks and tectonic processes, investigation of denudation histories and long-term landscape evolution of various geological settings, and basin analysis. Thermochronology may be described as the the analysis of radiation damage trails (‘fission quantitative study of the thermal histories of rocks tracks’) in uranium-bearing, non-conductive using temperature-sensitive radiometric dating minerals and glasses. It is routinely applied on the methods such as 40Ar/39Ar and K–Ar, fission minerals apatite, zircon and titanite. Fission tracks track, and (U–Th)/He (Berger & York 1981). are produced continuously through geological time Amongst these different methods, apatite fission as a result of the spontaneous fission of 238U track (AFT) and apatite (U–Th–Sm)/He (AHe) atoms. They are submicroscopic features with an are now, perhaps, the most widely used thermo- initial width of approximately 10 nm and a length chronometers as they are the most sensitive to low of up to 20 mm (Paul & Fitzgerald 1992) that can temperatures (typically between 40 and c.
    [Show full text]
  • Closure Temperature of (U-Th)/He System in Apatite Obtained from Natural Drillhole Samples in the Tarim Basin and Its Geological Significance
    Article Geology September 2012 Vol.57 No.26: 34823490 doi: 10.1007/s11434-012-5176-1 SPECIAL TOPICS: Closure temperature of (U-Th)/He system in apatite obtained from natural drillhole samples in the Tarim basin and its geological significance CHANG Jian1,2 & QIU NanSheng1,2* 1 State Key Laboratory of Petroleum Resource and Prospecting, China University of Petroleum, Beijing 102249, China; 2 Basin and Reservoir Research Center, China University of Petroleum, Beijing 102249, China Received February 27, 2012; accepted March 27, 2012; published online May 15, 2012 The apatite (U-Th)/He thermochronometry has been used to study the tectono-thermal evolution of mountains and sedimentary basins for over ten years. The closure temperature of helium is important for the apatite (U-Th)/He thermochronometry and has been widely studied by thermal simulation experiments. In this paper, the apatite He closure temperature was studied by estab- lishing the evolutionary pattern between apatite He ages and apatite burial depth based on examined apatite He ages of natural samples obtained from drillholes in the Tarim basin, China. The study showed that the apatite He closure temperature of natural samples in the Tarim basin is approximately 88±5°C, higher than the result (~75°C) obtained from the thermal simulation exper- iments. The high He closure temperature resulted from high effective uranium concentration, long-term radiation damage accu- mulation, and sufficient particle radii. This study is a reevaluation of the conventional apatite He closure temperature and has a great significance in studying the uplifting events in the late period of the basin-mountain tectonic evolution, of which the uplift- ing time and rates can be determined accurately.
    [Show full text]
  • 4. Thermochronology – Techniques and Methods
    4. Thermochronology – Techniques and Methods 4.1 Introduction to thermochronology Thermochronology is the study of dating the cooling of rocks through exhumation. In its simplest form, thermochronology can be considered to date the moment when a mineral passes through a specific closure temperature (Tc) (Dodson, 1973). Minerals have different closure temperatures and so by using a suite of thermochronometers on a single sample, its cooling path through the crust can be reconstructed. The minerals and closure temperatures available for use are illustrated in figure 4.1. The highest temperature chronometers have closure temperatures in excess of 750oC (U-Pb in zircon). These higher temperature chronometers such as the U-Pb system in zircon are used to date, for example, Archean gneiss terrains, due to the unlikely nature of them having been reset, with depths required for reset at ~30 km (assuming a 25oCkm-1 geothermal gradient). This study focuses on the low temperature thermochronometers which may allow the geomorphic signature of the landscape to become etched into the thermochronometric record. Two principal low temperature thermochronometers are used in this study, apatite fission track analysis (AFT) and apatite (U-Th)/He analysis (AHe). These are the lowest temperature chronometers that are known about in sufficient detail and calibrated well enough to make them usable. The low temperature thermochronometers may be used in a variety of ways, but one of their principal uses and that used in this study is to determine the temperature-time history of samples. As an extension to this they may also be used to determine exhumation rates by making some assumptions and for the higher temperature chronometers, to date the timing of formation of the rock/mineral in question.
    [Show full text]
  • Apatite (U^Th)/He Thermochronometry: Methods and Applications to Problems in Tectonic and Surface Processes
    Earth and Planetary Science Letters 206 (2003) 1^14 www.elsevier.com/locate/epsl Frontiers Apatite (U^Th)/He thermochronometry: methods and applications to problems in tectonic and surface processes Todd A. Ehlers Ã, Kenneth A. Farley California Institute of Technology, Division of Geological and Planetary Sciences, MC 100-23, Pasadena, CA91125, USA Received 11 July 2002; received in revised form 1 October 2002; accepted 5 November 2002 Abstract In the last decade apatite (U^Th)/He thermochronometry has emerged as an important tool for quantifying the cooling history of rocks as they pass through the upper 1^3 km of the crust. The low closure temperature of this technique (V70‡C) has gained the interest of geomorphologists and tectonocists because it is applicable to interdisciplinary studies in landform evolution, structural geology, and geodynamics. We discuss current analytical techniques, the temperature calibration of the method, and sample quality considerations. Results from 1D, 2D and 3D thermo-kinematic numerical models are used to illustrate applications of He thermochronometry to problems in tectonics and landform evolution. ß 2002 Elsevier Science B.V. All rights reserved. Keywords: apatite; (U^Th)/He; thermochronometry; surface processes; tectonics; numerical modeling 1. Introduction chronometry. The focus on apatite arises from its ubiquity and moderately high U and Th content, A recent resurgence of interest in dating miner- but more importantly because He accumulation in als via 4He ingrowth has been driven by an im- apatite occurs only at temperatures below V70^ proved understanding of the behavior of He in 75‡C [9]. At higher temperatures di¡usion re- minerals [1^4], development of robust analytical moves He as fast as it is produced by decay.
    [Show full text]
  • Fission Track Constraints on Exhumation and Extensional Faulting in Southwest Nevada and Eastern California, U.S.A
    FISSION TRACK CONSTRAINTS ON EXHUMATION AND EXTENSIONAL FAULTING IN SOUTHWEST NEVADA AND EASTERN CALIFORNIA, U.S.A. Prepared for U.S. Nuclear Regulatory Commission Contract NRC–02–07–006 Prepared by David A. Ferrill,1 Alan P. Morris,1 John A. Stamatakos,2 Deborah J. Waiting,2 Raymond A. Donelick,3 Ann E. Blythe4 1Department of Earth, Material, and Planetary Sciences Southwest Research Institute® San Antonio, Texas 2Center for Nuclear Waste Regulatory Analyses San Antonio, Texas 3Apatite to Zircon, Inc. Viola, Idaho 4Department of Geology Occidental College Los Angeles, California September 2011 ABSTRACT Eastern California and southwestern Nevada is an area of Tertiary and Quaternary extensional and dextral transtensional deformation. We use zircon and apatite fission-track thermochronology to study the distribution and timing of tectonic exhumation resulting from extensional and transtensional detachment faulting in this area. Samples were collected from outcrops around Yucca Flat and Frenchman Flat, the Striped Hills, Mount Stirling, Resting Spring Range, Bare Mountain, Bullfrog Hills, and the eastern margin of the Funeral Mountains. To constrain timing of exhumation associated with crustal-scale normal faulting, sampling efforts were focused on Paleozoic and Precambrian clastic sedimentary and metasedimentary rocks of the Stirling Quartzite, Wood Canyon Formation, Zabriskie Quartzite, Eureka Quartzite, and Eleana Formation. Sixty-nine new apatite and zircon fission-track cooling ages from 50 samples, analyzed in conjunction with published fission-track data from the region, indicate a distinct population of young (Miocene) fission-track ages and a population of irregularly distributed older (pre-Miocene) fission-track ages. Miocene (young population) fission track ages young westwards—indicating westward migration of the cooling front, consistent with well-documented Miocene extension of the Basin and Range.
    [Show full text]
  • (U–Th)/He Thermochronometry Using a Radiation Damage Accumulation and Annealing Model
    Available online at www.sciencedirect.com Geochimica et Cosmochimica Acta 73 (2009) 2347–2365 www.elsevier.com/locate/gca Apatite (U–Th)/He thermochronometry using a radiation damage accumulation and annealing model Rebecca M. Flowers a,*, Richard A. Ketcham b, David L. Shuster c, Kenneth A. Farley d a Department of Geological Sciences, University of Colorado at Boulder, 2200 Colorado Ave., UCB 399, Boulder, CO 80309, USA b Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78712, USA c Berkeley Geochronology Center, 2455 Ridge Road, Berkeley, CA 94709, USA d Department of Geological and Planetary Sciences, California Institute of Technology, MS 170-25, Pasadena, CA 91125, USA Received 13 October 2008; accepted in revised form 21 January 2009; available online 11 March 2009 Abstract Helium diffusion from apatite is a sensitive function of the volume fraction of radiation damage to the crystal, a quantity that varies over the lifetime of the apatite. Using recently published laboratory data we develop and investigate a new kinetic model, the radiation damage accumulation and annealing model (RDAAM), that adopts the effective fission-track density as a proxy for accumulated radiation damage. This proxy incorporates creation of crystal damage proportional to a-production from U and Th decay, and the elimination of that damage governed by the kinetics of fission-track annealing. The RDAAM is a version of the helium trapping model (HeTM; Shuster D. L., Flowers R. M. and Farley K. A. (2006) The influence of nat- ural radiation damage on helium diffusion kinetics in apatite. Earth Planet.
    [Show full text]
  • U-Th)/He Datasets
    minerals Article A Framework for Evaluating Variation in (U-Th)/He Datasets Francis J. Sousa 1,* and Kenneth A. Farley 2 1 College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA 2 Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA; [email protected] * Correspondence: [email protected] Received: 11 November 2020; Accepted: 8 December 2020; Published: 10 December 2020 Abstract: This paper presents a framework for evaluating variation in (U-Th)/He datasets. The framework is objective, repeatable, and based on compatibility of thermal histories derived from individual (U-Th)/He dates. The structure of this new method includes three fundamental steps. First, the allowable thermal history of each individual grain is quantitatively constrained with a model. Second, the thermal histories of all grains from a sample are visualized on the same axes. Third, the compatibility of the allowable thermal histories of each individual grain is evaluated. This allows a user to assess whether variation among single grain dates can plausibly be explained (referred to here as legitimate) or not (illegitimate). Additionally, this methodology allows for accurate representation of the impact that illegitimate variation has on the thermal history constraints of a sample. We demonstrate the application of this new framework using a variety of examples from the literature, as well as with synthetic data. Modeling presented here is executed using the modeling software QTQt (version 5.6.0) and the He diffusion kinetics based on the radiation damage accumulation and annealing model, but the framework is designed to be easily adaptable to any modeling software and diffusion parameters.
    [Show full text]
  • Grain-Size Effects on the Closure Temperature of White Mica in A
    Tectonophysics 674 (2016) 210–226 Contents lists available at ScienceDirect Tectonophysics journal homepage: www.elsevier.com/locate/tecto Grain-size effects on the closure temperature of white mica in a crustal-scale extensional shear zone — Implications of in-situ 40Ar/39Ar laser-ablation of white mica for dating shearing and cooling (Tauern Window, Eastern Alps) Andreas Scharf a,b,⁎,1,MarkR.Handya, Stefan M. Schmid a,c, Silvia Favaro a, Masafumi Sudo d, Ralf Schuster e, Konrad Hammerschmidt a a Department of Earth Sciences, Freie Universität Berlin, Malteserstrasse 74-100, 12249 Berlin, Germany b Department of Earth Science, Sultan Qaboos University, P.O. Box 36, Al-Khoudh, P.C. 123 Muscat, Oman c Institute of Geophysics, Eidgenössische Technische Hochschule (ETH), Sonneggstrasse 5, 8092 Zürich, Switzerland d Institute of Earth and Environmental Science, Universität Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam-Golm, Germany e Geologische Bundesanstalt, Neulinggasse 38, 1030 Wien, Austria article info abstract Article history: In-situ 40Ar/39Ar laser ablation dating of white-mica grains was performed on samples from the footwall of a Received 15 February 2015 crustal-scale extensional fault (Katschberg Normal Fault; KNF) that accommodated eastward orogen-parallel dis- Received in revised form 10 December 2015 placement of Alpine orogenic crust in the eastern part of the Tauern Window. This dating yields predominantly Accepted 5 February 2016 cooling ages ranging from 31 to 13 Myr, with most ages clustering between 21 and 17 Myr. Folded white micas Available online 24 February 2016 that predate the main Katschberg foliation yield, within error, the same ages as white-mica grains that overgrow Keywords: this foliation.
    [Show full text]
  • Fission Track Dating Generally Uses Uranium Rich Miner- Als
    Geol. 655 Isotope Geochemistry Lecture 14 Spring 2003 GEOCHRONOLOGY X: FISSON TRACK DATING INTRODUCTION As we have already noted, a frac- tion of uranium atoms undergo spontaneous fission rather than al- pha decay. The sum of the masses of the fragments is less than that of the parent U atom: this difference re- flects the greater binding energy of the fragments. The missing mass has been converted to kinetic energy of the fission fragments. Typically, this energy totals about 200 MeV, a con- siderable amount of energy on the atomic scale. The energy is depos- Figure 14.1. Fission tracks in a polished and etched ited in the crystal lattice through zircon. Photo courtesy J. M. Bird. which the fission fragments pass by stripping electrons from atoms in the crystal lattice. The ionized atoms repel each other, disordering the lattice and producing a small channel and a wider stressed region in the crystal. The damage is visible as tracks seen with an electron microscope operating at magnifications of 50,000¥ or greater. However, the stressed region is more readily attacked and dissolved by acid; so by acid etching the tracks can be enlarged to the point where they are visible under the optical microscope. Figure 14.1 is an example. Because fission is a rare event in any case, fission track dating generally uses uranium rich miner- als. Most work has been done on apatites, but sphene and zircon are also commonly used. Fission tracks will anneal, or self-repair, over time. The rate of annealing is vanishingly small at room temperature, but increases with temperature and becomes significant at geologically low to moderate temperatures.
    [Show full text]
  • Petrochronology of Monazite and Zircon in Ultra-High Temperature Granulite from Rogaland, Norway Antonin Laurent
    Petrochronology of monazite and zircon in ultra-high temperature granulite from Rogaland, Norway Antonin Laurent To cite this version: Antonin Laurent. Petrochronology of monazite and zircon in ultra-high temperature granulite from Rogaland, Norway. Earth Sciences. Université Paul Sabatier - Toulouse III, 2016. English. NNT : 2016TOU30290. tel-01686377 HAL Id: tel-01686377 https://tel.archives-ouvertes.fr/tel-01686377 Submitted on 17 Jan 2018 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. 5)µ4& &OWVFEFMPCUFOUJPOEV %0$503"5%&-6/*7&34*5²%&506-064& %ÏMJWSÏQBS Université Toulouse 3 Paul Sabatier (UT3 Paul Sabatier) 1SÏTFOUÏFFUTPVUFOVFQBS Antonin LAURENT le mardi 8 novembre 2016 5JUSF Étude pétrologique et chronométrique (U–Th–Pb) de la monazite et du zircon dans les granulites de ultra-haute température du Rogaland, Norvège ²DPMF EPDUPSBMF et discipline ou spécialité ED SDU2E : Sciences de la Terre et des Planètes Solides 6OJUÏEFSFDIFSDIF Géosciences Environnement Toulouse – UMR 5563 %JSFDUFVSUSJDF T EFʾÒTF Mme Stéphanie Duchene (Directrice) Mme Anne-Magali Seydoux-Guillaume (Co-directrice) M. Bernard Bingen (Co-encadrant) Jury : M. Philippe GONCALVES Maître de conférences Rapporteur M. Simon HARLEY Professeur des universités Rapporteur M. Fernando CORFU Professeur des universités Examinateur M.
    [Show full text]
  • Applications and Limitations of U-Pb Thermochronology to Middle and Lower Crustal Thermal Histories T ⁎ A.J
    Chemical Geology 494 (2018) 1–18 Contents lists available at ScienceDirect Chemical Geology journal homepage: www.elsevier.com/locate/chemgeo Invited review article Applications and limitations of U-Pb thermochronology to middle and lower crustal thermal histories T ⁎ A.J. Smyea, , J.H. Marshb, P. Vermeeschc, J.M. Garbera, D.F. Stocklid a Department of Geosciences, Pennsylvania State University, University Park, PA 16801, USA b Mineral Exploration Research Centre, Harquail School of Earth Sciences, Laurentian University, Sudbury, ON P3E 2C6, Canada c Department of Earth Sciences, University College London, London, WC1E 6BT, UK d Department of Geological Sciences, The University of Texas at Austin, Austin, TX 78712, USA ARTICLE INFO ABSTRACT Keywords: Volume diffusion of Pb occurs over micron length scales in apatite and rutile at temperatures relevant to the Thermochronology evolution of the middle and lower crust. Continuous thermal history information can be resolved from inversion U-Pb of intracrystalline U-Pb date profiles preserved within individual grains. Recent developments in microbeam Rutile analysis permit rapid measurement of these age profiles at sub-micron spatial resolution, thus heralding a new Apatite era for U-Pb thermochronology. Here, we review the theoretical, experimental and empirical basis for U-Pb Titanite thermochronology and show that rutile, in particular, presents an exceptional opportunity to obtain high-re- Lower crust Diffusion solution thermal history information from the deep crust. We present a Bayesian procedure that is well suited to the inversion of U-Pb date profile datasets and balances computational efficiency with a full search of thermal history coordinate space. Complications relevant to accurate application of U-Pb thermochronology are dis- cussed i) theoretically and ii) empirically, using a rutile U-Pb dataset from the lower crust of the Grenville orogeny.
    [Show full text]