TY - JOUR
T1 - New shock microstructures in titanite (CaTiSiO5) from the peak ring of the Chicxulub impact structure, Mexico
AU - IODP-ICDP Expedition 364 Scientists
AU - Timms, Nicholas E.
AU - Pearce, Mark A.
AU - Erickson, Timmons M.
AU - Cavosie, Aaron J.
AU - Rae, Auriol S.P.
AU - Wheeler, John
AU - Wittmann, Axel
AU - Ferrière, Ludovic
AU - Poelchau, Michael H.
AU - Tomioka, Naotaka
AU - Collins, Gareth S.
AU - Gulick, Sean P.S.
AU - Rasmussen, Cornelia
AU - Morgan, Joanna V.
AU - Gulick, S. P.S.
AU - Morgan, J. V.
AU - Chenot, E.
AU - Christeson, G. L.
AU - Claeys, P.
AU - Cockell, C. S.
AU - Coolen, M. J.L.
AU - Ferrière, L.
AU - Gebhardt, C.
AU - Goto, K.
AU - Green, S.
AU - Jones, H.
AU - Kring, D. A.
AU - Lofi, J.
AU - Lowery, C. M.
AU - Ocampo-Torres, R.
AU - Perez-Cruz, L.
AU - Pickersgill, A. E.
AU - Poelchau, M. H.
AU - Rae, A. S.P.
AU - Rasmussen, C.
AU - Rebolledo-Vieyra, M.
AU - Riller, U.
AU - Sato, H.
AU - Smit, J.
AU - Tikoo, S. M.
AU - Tomioka, N.
AU - Urrutia-Fucugauchi, J.
AU - Whalen, M. T.
AU - Wittmann, A.
AU - Xiao, L.
AU - Yamaguchi, K. E.
N1 - Funding Information:
Fig. 11 Accessory phases as indicators of shock metamorphism. [1]—Leroux et al. (1999), [2]—Timms et al. (2012), [3]—Moser et al. (2009), [4]—Timms et al. (2017a), [5]—Erickson et al. (2013), [6]—Nemchin et al. (2009), [7]—Timms et al. (2018), [8]—Moser et al. (2011), [9]—Thomson et al. (2014), [10]—Cox et al. (2018), [11]—Wittmann et al. (2006), [12]—Cavosie et al. (2015b), [13]— Reddy et al. (2015), [14]—Erickson et al. (2017a), [15]—Cavosie et al. (2015a), [16]—Cavosie et al. (2016a), [17]—Cavosie et al. (2018b), [18]—Timms et al. (2017b), [19]—Erickson et al. (2015), at the John de Laeter Centre, Curtin University. ASPR received support from the Barringer Family Fund for Meteorite Impact Research and STFC (ST/J001260/1), and thanks R.A.F. Grieve and G.R. Osinski for their support. AJC acknowledges support from the NASA Astrobiology program (Grant #NNAI3AA94A) and a Curtin Senior Research Fellowship. TME acknowledges support from a Lunar and Planetary Institute Postdoctoral Research Fellowship, the Center for Lunar Science and Exploration, and D. Kring. AW, SG, and CR are supported by National Science Foundation (OCE-1737087 and 1737351). This is a UTIG Contribution #3447. J. Darling, W.U. Reimold, and two anonymous reviewers are thanked for their comments on earlier versions of the manuscript. We thank D. Rubatto for editorial handling.
Funding Information:
The Chicxulub drilling expedition was funded by the IODP as Expedition 364 with co-funding from the ICDP, implementation by ECORD, and contributions and logistical support from the Yucatán state government and UNAM. This research used samples provided by the IODP, funding provided by a UK IODP NERC Grant (NE/P011195/1), and a Tescan Mira3 FE-SEM (ARC LE130100053) at the John de Laeter Centre, Curtin University. ASPR received support from the Barringer Family Fund for Meteorite Impact Research and STFC (ST/J001260/1), and thanks R.A.F. Grieve and G.R. Osinski for their support. AJC acknowledges support from the NASA Astrobiology program (Grant #NNAI3AA94A) and a Curtin Senior Research Fellowship. TME acknowledges support from a Lunar and Planetary Institute Postdoctoral Research Fellowship, the Center for Lunar Science and Exploration, and D. Kring. AW, SG, and CR are supported by National Science Foundation (OCE-1737087 and 1737351).
Funding Information:
Acknowledgements The Chicxulub drilling expedition was funded by the IODP as Expedition 364 with co-funding from the ICDP, implementation by ECORD, and contributions and logistical support from the Yucatán state government and UNAM. This research used samples provided by the IODP, funding provided by a UK IODP NERC Grant (NE/P011195/1), and a Tescan Mira3 FE-SEM (ARC LE130100053)
Publisher Copyright:
© 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
PY - 2019/5/1
Y1 - 2019/5/1
N2 - Accessory mineral geochronometers such as apatite, baddeleyite, monazite, xenotime and zircon are increasingly being recognized for their ability to preserve diagnostic microstructural evidence of hypervelocity-impact processes. To date, little is known about the response of titanite to shock metamorphism, even though it is a widespread accessory phase and a U–Pb geochronometer. Here we report two new mechanical twin modes in titanite within shocked granitoid from the Chicxulub impact structure, Mexico. Titanite grains in the newly acquired core from the International Ocean Discovery Program Hole M0077A preserve multiple sets of polysynthetic twins, most commonly with composition planes (K1) = ~ { 1 ¯ 11 } , and shear direction (η1) = < 110 > , and less commonly with the mode K1 = {130}, η1 = ~ <522 >. In some grains, {130} deformation bands have formed concurrently with the deformation twins, indicating dislocation slip with Burgers vector b = < 341 > can be active during impact metamorphism. Titanite twins in the modes described here have not been reported from endogenically deformed rocks; we, therefore, propose this newly identified twin form as a result of shock deformation. Formation conditions of the twins have not been experimentally calibrated, and are here empirically constrained by the presence of planar deformation features in quartz (12 ± 5 and ~ 17 ± 5 GPa) and the absence of shock twins in zircon (< 20 GPa). While the lower threshold of titanite twin formation remains poorly constrained, identification of these twins highlight the utility of titanite as a shock indicator over the pressure range between 12 and 17 GPa. Given the challenges to find diagnostic indicators of shock metamorphism to identify both ancient and recent impact evidence on Earth, microstructural analysis of titanite is here demonstrated to provide a new tool for recognizing impact deformation in rocks where other impact evidence may be erased, altered, or did not manifest due to generally low (< 20 GPa) shock pressure.
AB - Accessory mineral geochronometers such as apatite, baddeleyite, monazite, xenotime and zircon are increasingly being recognized for their ability to preserve diagnostic microstructural evidence of hypervelocity-impact processes. To date, little is known about the response of titanite to shock metamorphism, even though it is a widespread accessory phase and a U–Pb geochronometer. Here we report two new mechanical twin modes in titanite within shocked granitoid from the Chicxulub impact structure, Mexico. Titanite grains in the newly acquired core from the International Ocean Discovery Program Hole M0077A preserve multiple sets of polysynthetic twins, most commonly with composition planes (K1) = ~ { 1 ¯ 11 } , and shear direction (η1) = < 110 > , and less commonly with the mode K1 = {130}, η1 = ~ <522 >. In some grains, {130} deformation bands have formed concurrently with the deformation twins, indicating dislocation slip with Burgers vector b = < 341 > can be active during impact metamorphism. Titanite twins in the modes described here have not been reported from endogenically deformed rocks; we, therefore, propose this newly identified twin form as a result of shock deformation. Formation conditions of the twins have not been experimentally calibrated, and are here empirically constrained by the presence of planar deformation features in quartz (12 ± 5 and ~ 17 ± 5 GPa) and the absence of shock twins in zircon (< 20 GPa). While the lower threshold of titanite twin formation remains poorly constrained, identification of these twins highlight the utility of titanite as a shock indicator over the pressure range between 12 and 17 GPa. Given the challenges to find diagnostic indicators of shock metamorphism to identify both ancient and recent impact evidence on Earth, microstructural analysis of titanite is here demonstrated to provide a new tool for recognizing impact deformation in rocks where other impact evidence may be erased, altered, or did not manifest due to generally low (< 20 GPa) shock pressure.
UR - http://www.scopus.com/inward/record.url?scp=85065307578&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85065307578&partnerID=8YFLogxK
U2 - 10.1007/s00410-019-1565-7
DO - 10.1007/s00410-019-1565-7
M3 - Article
AN - SCOPUS:85065307578
VL - 174
JO - Contributions to Mineralogy and Petrology
JF - Contributions to Mineralogy and Petrology
SN - 0010-7999
IS - 5
M1 - 38
ER -