Coupled Calibration and Application of the Extinct 107Pd-107Ag and 205Pb-205Tl Decay Systems
Lead Research Organisation:
Imperial College London
Department Name: Earth Science and Engineering
Abstract
The earliest history of planetary bodies in the solar system encompasses the accretion of the objects and their differentiation into silicate mantles and metallic cores. Subsequently the newly formed bodies cooled and solidified. Recent developments in modelling and analytical techniques have significantly improved our understanding of the timing and duration of some of these processes. The timescales over which differentiated asteroids cooled and their metallic cores crystallized remain poorly constrained, however. In this research project, we will address this shortcoming by studying the only samples of planetary cores that are available for direct analyses - iron meteorites. The approach will be to measure the decay products of the short-lived palladium-silver (107Pd-107Ag) and lead-thallium (205Pb-205Tl) radionuclide systems in such meteorites. These two decay schemes have half-lives of only about 10 Myr, and they can thus provide very precise (+/- a few Myr) ages of 'metal crystallization'. These ages define the time at which the metal, which was originally present in liquid form, had cooled to form a solid iron-rich core. To obtain such ages, the research project involves the following investigations: 1) The Pd-Ag and Pb-Tl decay systems first need to be calibrated before they can provide absolute age information. To obtain such a calibration, we will analyze meteorite samples for which precise absolute ages are already available. Once completed, the calibration will be of long-lasting value because it provides the basic foundation for the use of the Pd-Ag and Pb-Tl dating systems as precise absolute 'clocks' of processes that took place in the early solar system. 2) With this calibration, we will analyze the decay products of the Pd-Ag and Pb-Tl clocks in iron meteorites. These analyses will provide the precise ages at which the metallic cores of the asteroids, from which the iron meteorites were derived, cooled and crystallized. 3) This information will then be combined with the results of previous studies, which dated the age of 'metal segregation'. This is the time at which an originally primitive asteroid was heated to melting temperatures, such that it differentiated into an outer mantle composed of silicates and a core composed mainly of liquid metallic iron. By comparing the 'metal segregation' with the 'metal crystallization' age, we can infer the rate at which the metal core of an asteroid cooled. As this 'cooling rate' is primarily a function of the size (with larger bodies cooling slower than smaller ones), we can use this information to estimate the diameter of the asteroidal precursor of an iron meteorite. This implies that our data will enable us, for the first time, to relate the duration of accretion to the size of a given asteroidal parent body. In this study, we will analyze various groups of iron meteorites, which are derived from distinct asteroids. The age information that we will obtain for these samples, together with previous results, will provide comprehensive chronological records for the parent asteroids of most iron meteorites. These records will span the period from accretion and concomitant core formation to the cooling and crystallization of the metallic cores. Taken together, this information will significantly expand our understanding of the chemical, physical and thermal evolution of asteroids in the early solar system.
People |
ORCID iD |
Mark Rehkamper (Principal Investigator) |
Publications
Arnold T
(2010)
Measurement of zinc stable isotope ratios in biogeochemical matrices by double-spike MC-ICPMS and determination of the isotope ratio pool available for plants from soil.
in Analytical and bioanalytical chemistry
Hendry K
(2009)
The cadmium-phosphate relationship in brine: biological versus physical control over micronutrients in sea ice environments
in Antarctic Science
Arnold T
(2015)
Iron and zinc isotope fractionation during uptake and translocation in rice (Oryza sativa) grown in oxic and anoxic soils
in Comptes Rendus. Géoscience
Baker R
(2010)
The thallium isotope composition of carbonaceous chondrites - New evidence for live 205Pb in the early solar system
in Earth and Planetary Science Letters
Theis K
(2013)
Palladium-silver chronology of IAB iron meteorites
in Earth and Planetary Science Letters
Hezel D
(2010)
A nebula setting as the origin for bulk chondrule Fe isotope variations in CV chondrites
in Earth and Planetary Science Letters
Bridgestock L
(2014)
Unlocking the zinc isotope systematics of iron meteorites
in Earth and Planetary Science Letters
Laycock A
(2016)
Earthworm Uptake Routes and Rates of Ionic Zn and ZnO Nanoparticles at Realistic Concentrations, Traced Using Stable Isotope Labeling.
in Environmental science & technology
Larner F
(2012)
Evaluation of stable isotope tracing for ZnO nanomaterials--new constraints from high precision isotope analyses and modeling.
in Environmental science & technology
Horner T
(2010)
Ferromanganese crusts as archives of deep water Cd isotope compositions
in Geochemistry, Geophysics, Geosystems
Abouchami W.
(2010)
In search of a common reference material for cadmium isotope studies
in GEOCHIMICA ET COSMOCHIMICA ACTA
Baker R
(2010)
Thallium isotope variations in an ore-bearing continental igneous setting: Collahuasi Formation, northern Chile
in Geochimica et Cosmochimica Acta
Baker R
(2009)
Investigation of thallium fluxes from subaerial volcanism-Implications for the present and past mass balance of thallium in the oceans
in Geochimica et Cosmochimica Acta
Pickard H
(2022)
The cadmium and zinc isotope compositions of the silicate Earth - Implications for terrestrial volatile accretion
in Geochimica et Cosmochimica Acta
Larner F
(2011)
A new separation procedure for Cu prior to stable isotope analysis by MC-ICP-MS
in Journal of Analytical Atomic Spectrometry
Larner F
(2015)
Zinc isotopic compositions of breast cancer tissue.
in Metallomics : integrated biometal science
Benedix G. K.
(2010)
TRACE ELEMENT COMPOSITION OF A SULFIDE NODULE IN TOLUCA IAB IRON
in METEORITICS & PLANETARY SCIENCE
Theis K. J.
(2010)
CHRONOLOGY OF IAB IRON METEORITES USING THE Pd-Ag DECAY SYSTEM
in METEORITICS & PLANETARY SCIENCE
Theis K. J.
(2011)
DATING CORE CRYSTALLIZATION OF IIAB AND IIIAB IRON METEORITES USING THE PALLADIUM-SILVER DECAY SYSTEM
in METEORITICS & PLANETARY SCIENCE
FEHR M
(2010)
Tellurium isotope compositions of calcium-aluminum-rich inclusions
in Meteoritics & Planetary Science
Fehr Manuela A.
(2009)
Tellurium isotope compositions of calcium-aluminum-rich inclusions
in METEORITICS & PLANETARY SCIENCE
Palk C. S.
(2011)
EXTREME CADMIUM AND THALLIUM ISOTOPE FRACTIONATIONS IN ENSTATITE CHONDRITES
in METEORITICS & PLANETARY SCIENCE
Giscard M. D.
(2012)
TRACE ELEMENT COMPOSITION OF METAL AND SULPHIDES IN IRON METEORITES DETERMINED USING ICP-MS
in METEORITICS & PLANETARY SCIENCE
Huber L.
(2011)
THE IMPORTANCE OF COSMIC RAY EFFECTS FOR PALLADIUM-SILVER CHRONOMETRY IN IRON METEORITES: AN EVALUATION USING NOBLE GASES
in METEORITICS & PLANETARY SCIENCE
Hezel D
(2015)
Fe and O isotope composition of meteorite fusion crusts: Possible natural analogues to chondrule formation?
in Meteoritics & Planetary Science
Palk E
(2017)
Variable Tl, Pb, and Cd concentrations and isotope compositions of enstatite and ordinary chondrites-Evidence for volatile element mobilization and decay of extinct 205 Pb
in Meteoritics & Planetary Science
Wood BJ
(2010)
Volatile accretion history of the Earth.
in Nature
Hunt A
(2022)
The dissipation of the solar nebula constrained by impacts and core cooling in planetesimals
in Nature Astronomy
Rehkämper M
(2012)
Handbook of Environmental Isotope Geochemistry - Vol I
Rehkämper M
(2012)
Isotopic Analysis - Fundamentals and Applications Using ICP-MS
Description | Our new data (i) provide an improved chronological understanding of the accretion and cooling history of iron meteorite parent bodies (ii) show that the extinct Pd-Ag and Pb-Tl chronometers must be applied with care because Ag and Tl isotope variations can also be generated by stable isotope fractionations (iii) demonstrate that the Pb-Tl chronometer is particularly tricky in its application, due to ubiquitous contamination of meteorites with terrestrial Pb (iv) that stable isotope data for volatile elements (e.g., for Ag, Cd, Zn) in meteorites must be interpreted with care as isotopic variations may be caused by both nebular/parent body wide processes and reactions occurring on a local scale (such as thermal metamorphism, mineral-scale partitioning). |
Exploitation Route | Academic - stable isotope analyses of meteorites show much potential for improving our understanding of early solar system processes. Non-academic - the high-precision isotope measurement techniques that were developed as part of the project have huge potential for application in other fields of research. For example, I received an STFC Impact Award from Imperial College, which investigates use of the Zn isotope methods as a new diagnostic tool for breast cancer. |
Sectors | Agriculture, Food and Drink,Education,Environment,Healthcare |
Description | The high-precision isotope measurement techniques that were developed as part of the project have huge potential for application in other fields of research. As an example, I received an STFC Impact Award from Imperial College, which investigates use of the Zn isotope methods as a new diagnostic tool for breast cancer. |
First Year Of Impact | 2011 |
Sector | Agriculture, Food and Drink,Education,Environment,Healthcare |
Impact Types | Societal,Economic |
Description | STFC Consolidated Grant |
Amount | £442,510 (GBP) |
Funding ID | Subproject A of ST/J001260/1 |
Organisation | Science and Technologies Facilities Council (STFC) |
Sector | Public |
Country | United Kingdom |
Start | 04/2012 |
End | 03/2015 |
Description | STFC Quota PhD Studentship to Dept |
Amount | £60,000 (GBP) |
Organisation | Science and Technologies Facilities Council (STFC) |
Sector | Public |
Country | United Kingdom |
Start | 10/2009 |
End | 09/2012 |
Description | Joint isotopic research in cosmochemistry |
Organisation | Natural History Museum |
Department | Department of Mineralogy |
Country | United Kingdom |
Sector | Public |
PI Contribution | Contribution to joint research |
Collaborator Contribution | Joint research and joint supervision of STFC quota studentships to Imperial College |
Impact | Publications |
Start Year | 2010 |
Description | Preparation of a new Cd isotope reference material |
Organisation | Max Planck Society |
Department | Max Planck Institute for Chemistry |
Country | Germany |
Sector | Academic/University |
PI Contribution | Contribution to joint preparation of a new Cd isotope reference material |
Collaborator Contribution | Joint research |
Impact | in progress |
Start Year | 2009 |
Description | Preparation of a new Cd isotope reference material |
Organisation | University of Cologne |
Department | Institute of Geology and Mineralogy |
Country | Germany |
Sector | Academic/University |
PI Contribution | Contribution to joint preparation of a new Cd isotope reference material |
Collaborator Contribution | Joint research |
Impact | in progress |
Start Year | 2009 |
Description | Preparation of a new Cd isotope reference material |
Organisation | University of Oxford |
Department | Department of Earth Sciences |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Contribution to joint preparation of a new Cd isotope reference material |
Collaborator Contribution | Joint research |
Impact | in progress |
Start Year | 2009 |
Title | New isotopic measuremement techniques |
Description | New high-precision measurements methods for isotope compositions of Zn, Cd, Tl |
Type Of Technology | Detection Devices |
Year Produced | 2010 |
Impact | The isotopic methods and expertise that were developed in this study have helped to advance presently active studies, which apply novel isotopic techniques for medical and life science research and, most recently, in the rapidly growing field of nanopart |
Description | Discussion of nuclear forensics |
Form Of Engagement Activity | Participation in an open day or visit at my research institution |
Part Of Official Scheme? | No |
Primary Audience | Industry/Business |
Results and Impact | Gave presentation in seminar attended by about 30 policymakers, industry and other academics. Further workshops with industry and policymakers are taking place |
Year(s) Of Engagement Activity | 2010 |
Description | Earthclass Outreach Events |
Form Of Engagement Activity | Participation in an open day or visit at my research institution |
Part Of Official Scheme? | No |
Type Of Presentation | Workshop Facilitator |
Geographic Reach | National |
Primary Audience | Schools |
Results and Impact | Earthclass is a free outreach event that is hosted regularly in the Department of Earth Science and Engineering (ESE) at Imperial College London, driven by the desire to better communicate geosciences to young people. The event provides fun, interactive learning experiences for school children in the UK, whilst simultaneously improving their understanding of important issues such as climate change. Excellent feedback from participatin students, who felt that they were more likely to study a STEM subject at A-Level or university level, and would even consider studying Earth Science and Engineering at university. |
Year(s) Of Engagement Activity | 2012,2013 |
Description | NHM Science Uncovered 2012 |
Form Of Engagement Activity | Participation in an open day or visit at my research institution |
Part Of Official Scheme? | Yes |
Type Of Presentation | Keynote/Invited Speaker |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Hundreds of people visited the booth of the NHM Meteoritics group, which I supported for this event. I had discussions about meteorites, the formation of the Earth with dozens of interested members of the public. The event was extremely successful and wil be repeated next year. Numerous media covered the event and also reported on the work of the meteorics group. |
Year(s) Of Engagement Activity | 2011,2012 |
Description | UK Space Design Competition |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | Yes |
Type Of Presentation | Workshop Facilitator |
Geographic Reach | National |
Primary Audience | Schools |
Results and Impact | In 2013, 48 students participated in the event. The main aim of the competition is to provide students with an opportunity to take part in a design simulation that exposes them to the joys and challenges of working in a large industrial team. Students will develop a space-based infrastructure that requires complex, challenging, and imaginative thinking leading to an increased interest in science, engineering, technology, and mathematics. See http://uksdc.org/ |
Year(s) Of Engagement Activity | 2012,2013 |
Description | Workshop about nuclear forensics |
Form Of Engagement Activity | Participation in an open day or visit at my research institution |
Part Of Official Scheme? | No |
Primary Audience | Policymakers/politicians |
Results and Impact | Workshop for policy makers (mainly from Home Office, including Chief Scientific advisor to Home Office) held at Imperial College Planning of further activities in progress |
Year(s) Of Engagement Activity | 2011 |