Imperial College London
Alternate

ProfessorJoannaMorgan

Faculty of Engineering, Department of Earth Science & Engineering

Emeritus Professor of Geophysics
 
 
 
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Contact

 

+44 (0)20 7594 6423j.v.morgan

 
 
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Location

 

1.46CRoyal School of MinesSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Rasmussen:2019:10.1016/j.chemgeo.2019.07.029,
author = {Rasmussen, C and Stockli, DF and Ross, CH and Pickersgill, A and Gulick, SP and Schmieder, M and Christeson, GL and Wittmann, A and Kring, DA and Morgan, JV},
doi = {10.1016/j.chemgeo.2019.07.029},
journal = {Chemical Geology},
pages = {356--367},
title = {U-Pb memory behavior in Chicxulub's peak ring - Applying U-Pb depth profiling to shocked zircon},
url = {http://dx.doi.org/10.1016/j.chemgeo.2019.07.029},
volume = {525},
year = {2019}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - The zircon U-Pb system is one of the most robust geochronometers, but during an impact event individual crystals can be affected differently by the passage of the shock wave and impact generated heat. Unraveling the potentially complex thermal history recorded by zircon crystals that experienced variable levels of shock and heating, as well as additioanl pre- and post-impact thermal events, has been difficult using classical geochronological methods. The existing high-precision 40Ar/39Ar age constraints for the K-Pg Chicxulub event, and the previous U-Pb dating of the basement rocks from the impact site, make Chicxulub an ideal location to study impact-induced effects on the zircon U-Pb systematics and to evaluate potential 'memory effects' of pre-impact U-Pb signatures preserved within those individual zircon crystals. Recent IODP-ICDP drilling of the Chicxulub impact structure recovered 580m of uplifted shocked granitoid and 130m of melt and suevite, providing an unprecedented opportunity to study zircon crystals subjected to a range of shock pressures, thermal, and deformational histories. Zircon morphologies were classified using scanning electron microscopy (SEM) imaging and then samples were depth profiled using laser ablation inductively coupled plasma mass-spectrometry (LA-ICP-MS) to document the range of preserved age domains from rim-to-center within individual crystals. The results show U-Pb ages range from 66 to 472Ma, which are consistent with both inherited Carboniferous and Late Paleozoic basement ages as well as Pb loss ages in response to the K-Pg impact event. While the bulk of the zircon grains preserve Paleozoic ages, high U (metamict) zones within fractured zircon crystals exhibited an age within uncertainty (66±6.2Ma) of the impact age (66.038±0.049Ma), indicating that inherited intragrain U-Pb kinetics and/or hydrothermal fluid flow may have controlled age resetting those zircon crystals rather than impact-induced shock
AU  - Rasmussen,C
AU  - Stockli,DF
AU  - Ross,CH
AU  - Pickersgill,A
AU  - Gulick,SP
AU  - Schmieder,M
AU  - Christeson,GL
AU  - Wittmann,A
AU  - Kring,DA
AU  - Morgan,JV
DO  - 10.1016/j.chemgeo.2019.07.029
EP  - 367
PY  - 2019///
SN  - 0009-2541
SP  - 356
TI  - U-Pb memory behavior in Chicxulub's peak ring - Applying U-Pb depth profiling to shocked zircon
T2  - Chemical Geology
UR  - http://dx.doi.org/10.1016/j.chemgeo.2019.07.029
UR  - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000501715700025&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
UR  - https://www.sciencedirect.com/science/article/pii/S0009254119303493?via%3Dihub
UR  - http://hdl.handle.net/10044/1/77978
VL  - 525
ER  -
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