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New Techniques for Noble Gas Geochronometry and Thermochronometry

Citation

Cox, Stephen Ellis (2017) New Techniques for Noble Gas Geochronometry and Thermochronometry. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/Z9V69GKV. http://resolver.caltech.edu/CaltechTHESIS:12212016-095346656

Abstract

Noble gases were among the first species measured by mass spectrometry and interrogated for geochemical information about the solid Earth. The analytical challenge of measuring them has driven technological development in the field, and new applications have in turn followed from new developments. In the first chapter, I present developments that bolster an existing technique, the (U–Th)/Ne system, by verifying the theoretical underpinnings of the method and by exploring its application in several minerals. In the second chapter, I show that the hematite (U–Th)/Ne system is a sound geochronometer for use in the upper crust and a potent thermochronometer for exploring mid-crustal processes. In the third chapter I show significant advances toward using a quadrupole ion trap as a noble gas mass spectrometer, including the first static vacuum measurements. This technique provides new opportunities for low abundance noble gas measurements through its ultra low dark noise time of flight measurement approach and its high resolution, high mass range scanning capabilities. The quadrupole ion trap can measure lower concentrations of rare species like 3He and 21Ne on Earth, allowing us to make more precise determinations of cosmogenic exposure ages, and it can measure species with much higher resolution than is currently possible on most spaceflight instruments, allowing us to perform measurements on planetary surfaces and in deep space that are currently reserved to terrestrial laboratories. Finally, in the fourth chapter I demonstrate that an old, largely abandoned technique, (U–Th)/He geochronometry, has useful applications now that we fully understand its limitations.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Neon; Helium; (U–Th)/Ne; (U-Th)/He; Ion Trap; Quadrupole Ion Trap; QIT; Mono Lake; Allanite
Degree Grantor:California Institute of Technology
Division:Geological and Planetary Sciences
Major Option:Geochemistry
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Farley, Kenneth A.
Thesis Committee:
  • Burnett, Donald S.
  • Eiler, John M.
  • Farley, Kenneth A.
  • Rossman, George Robert (chair)
Defense Date:19 December 2016
Non-Caltech Author Email:cox.stephen.e (AT) gmail.com
Funders:
Funding AgencyGrant Number
National Science FoundationNSF-EAR-1144500
NASA/JPLPDF
National Science FoundationGRFP
Record Number:CaltechTHESIS:12212016-095346656
Persistent URL:http://resolver.caltech.edu/CaltechTHESIS:12212016-095346656
DOI:10.7907/Z9V69GKV
Related URLs:
URLURL TypeDescription
doi:10.1016/j.epsl.2011.12.025DOIArticle Adapter for Chapter Four.
doi:10.1016/j.gca.2014.08.036DOIArticle Adapter for Chapter One.
ORCID:
AuthorORCID
Cox, Stephen Ellis0000-0002-8819-887X
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:10000
Collection:CaltechTHESIS
Deposited By: Stephen Cox
Deposited On:01 Feb 2017 19:58
Last Modified:13 Feb 2017 19:56

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