I-Xe ages of enstatite chondrites

Jens Hopp, Mario Trieloff, U. Ott

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

In order to elucidate the early thermal history of enstatite chondrite parent bodies we determined 129I-129Xe whole rock ages of enstatite chondrites (5 EH, 2 EL, one EH impact melt) relative to the Shallowater reference meteorite (4562.3±0.4Ma, all errors are 1σ). I-Xe ages of both EL6 chondrites (LON 94100: -4.38±0.60Ma and Neuschwanstein: -3.87±0.73Ma - negative sign indicates ages younger than Shallowater) agree well with data of other EL6 chondrites. LON 94100 displayed a second isochron at lower temperatures equivalent to a younger age of -5.25±1.17Ma, perhaps reflecting different retention temperatures of respective carrier phases during sequential cooling. The enstatite chondrites Abee (EH4), Indarch (EH4), EET 96135 (EH4/5) and St. Marks (EH5) encompass a I-Xe age range of +0.57±1.05Ma (EET 96135 #1) to -0.45±0.72Ma (Abee), again in agreement with previously reported ages of EH chondrites. Only the age of St. Marks differs strongly from previously reported younger ages, now being more in accordance with other members of the EH clan. The EH3 chondrite Sahara 97096 showed the youngest I-Xe age of -7.87±0.46Ma distinctly younger than other I-Xe ages of EH chondrites, including other EH3s. Due to the apparent high retention temperature of the I-Xe system in enstatite (estimated >800°C) this young age implies a later resetting of the I-Xe system by a severe thermal, likely impact-induced, event. The EH impact melt LAP 02225 records a similarly young thermal event. Though no isochron relationship could be established, the data fall within an apparent I-Xe age range of +5 to +15Ma, similar to Sahara 97096. Overall, EH chondrite parent body experienced a thermal history determined by a complex interplay between impact disturbances and parent body metamorphism.

Original languageEnglish
Pages (from-to)196-210
Number of pages15
JournalGeochimica et Cosmochimica Acta
Volume174
DOIs
Publication statusPublished - Feb 1 2016

Fingerprint

enstatite chondrite
chondrite
Meteorites
parent body
Temperature
Rocks
Cooling
Hot Temperature
melt
resetting
enstatite
history
young
meteorite

ASJC Scopus subject areas

  • Geochemistry and Petrology

Cite this

I-Xe ages of enstatite chondrites. / Hopp, Jens; Trieloff, Mario; Ott, U.

In: Geochimica et Cosmochimica Acta, Vol. 174, 01.02.2016, p. 196-210.

Research output: Contribution to journalArticle

Hopp, Jens ; Trieloff, Mario ; Ott, U. / I-Xe ages of enstatite chondrites. In: Geochimica et Cosmochimica Acta. 2016 ; Vol. 174. pp. 196-210.
@article{49a15e1d4f8648bb8f812dec5da91531,
title = "I-Xe ages of enstatite chondrites",
abstract = "In order to elucidate the early thermal history of enstatite chondrite parent bodies we determined 129I-129Xe whole rock ages of enstatite chondrites (5 EH, 2 EL, one EH impact melt) relative to the Shallowater reference meteorite (4562.3±0.4Ma, all errors are 1σ). I-Xe ages of both EL6 chondrites (LON 94100: -4.38±0.60Ma and Neuschwanstein: -3.87±0.73Ma - negative sign indicates ages younger than Shallowater) agree well with data of other EL6 chondrites. LON 94100 displayed a second isochron at lower temperatures equivalent to a younger age of -5.25±1.17Ma, perhaps reflecting different retention temperatures of respective carrier phases during sequential cooling. The enstatite chondrites Abee (EH4), Indarch (EH4), EET 96135 (EH4/5) and St. Marks (EH5) encompass a I-Xe age range of +0.57±1.05Ma (EET 96135 #1) to -0.45±0.72Ma (Abee), again in agreement with previously reported ages of EH chondrites. Only the age of St. Marks differs strongly from previously reported younger ages, now being more in accordance with other members of the EH clan. The EH3 chondrite Sahara 97096 showed the youngest I-Xe age of -7.87±0.46Ma distinctly younger than other I-Xe ages of EH chondrites, including other EH3s. Due to the apparent high retention temperature of the I-Xe system in enstatite (estimated >800°C) this young age implies a later resetting of the I-Xe system by a severe thermal, likely impact-induced, event. The EH impact melt LAP 02225 records a similarly young thermal event. Though no isochron relationship could be established, the data fall within an apparent I-Xe age range of +5 to +15Ma, similar to Sahara 97096. Overall, EH chondrite parent body experienced a thermal history determined by a complex interplay between impact disturbances and parent body metamorphism.",
author = "Jens Hopp and Mario Trieloff and U. Ott",
year = "2016",
month = "2",
day = "1",
doi = "10.1016/j.gca.2015.11.014",
language = "English",
volume = "174",
pages = "196--210",
journal = "Geochmica et Cosmochimica Acta",
issn = "0016-7037",
publisher = "Elsevier Limited",

}

TY - JOUR

T1 - I-Xe ages of enstatite chondrites

AU - Hopp, Jens

AU - Trieloff, Mario

AU - Ott, U.

PY - 2016/2/1

Y1 - 2016/2/1

N2 - In order to elucidate the early thermal history of enstatite chondrite parent bodies we determined 129I-129Xe whole rock ages of enstatite chondrites (5 EH, 2 EL, one EH impact melt) relative to the Shallowater reference meteorite (4562.3±0.4Ma, all errors are 1σ). I-Xe ages of both EL6 chondrites (LON 94100: -4.38±0.60Ma and Neuschwanstein: -3.87±0.73Ma - negative sign indicates ages younger than Shallowater) agree well with data of other EL6 chondrites. LON 94100 displayed a second isochron at lower temperatures equivalent to a younger age of -5.25±1.17Ma, perhaps reflecting different retention temperatures of respective carrier phases during sequential cooling. The enstatite chondrites Abee (EH4), Indarch (EH4), EET 96135 (EH4/5) and St. Marks (EH5) encompass a I-Xe age range of +0.57±1.05Ma (EET 96135 #1) to -0.45±0.72Ma (Abee), again in agreement with previously reported ages of EH chondrites. Only the age of St. Marks differs strongly from previously reported younger ages, now being more in accordance with other members of the EH clan. The EH3 chondrite Sahara 97096 showed the youngest I-Xe age of -7.87±0.46Ma distinctly younger than other I-Xe ages of EH chondrites, including other EH3s. Due to the apparent high retention temperature of the I-Xe system in enstatite (estimated >800°C) this young age implies a later resetting of the I-Xe system by a severe thermal, likely impact-induced, event. The EH impact melt LAP 02225 records a similarly young thermal event. Though no isochron relationship could be established, the data fall within an apparent I-Xe age range of +5 to +15Ma, similar to Sahara 97096. Overall, EH chondrite parent body experienced a thermal history determined by a complex interplay between impact disturbances and parent body metamorphism.

AB - In order to elucidate the early thermal history of enstatite chondrite parent bodies we determined 129I-129Xe whole rock ages of enstatite chondrites (5 EH, 2 EL, one EH impact melt) relative to the Shallowater reference meteorite (4562.3±0.4Ma, all errors are 1σ). I-Xe ages of both EL6 chondrites (LON 94100: -4.38±0.60Ma and Neuschwanstein: -3.87±0.73Ma - negative sign indicates ages younger than Shallowater) agree well with data of other EL6 chondrites. LON 94100 displayed a second isochron at lower temperatures equivalent to a younger age of -5.25±1.17Ma, perhaps reflecting different retention temperatures of respective carrier phases during sequential cooling. The enstatite chondrites Abee (EH4), Indarch (EH4), EET 96135 (EH4/5) and St. Marks (EH5) encompass a I-Xe age range of +0.57±1.05Ma (EET 96135 #1) to -0.45±0.72Ma (Abee), again in agreement with previously reported ages of EH chondrites. Only the age of St. Marks differs strongly from previously reported younger ages, now being more in accordance with other members of the EH clan. The EH3 chondrite Sahara 97096 showed the youngest I-Xe age of -7.87±0.46Ma distinctly younger than other I-Xe ages of EH chondrites, including other EH3s. Due to the apparent high retention temperature of the I-Xe system in enstatite (estimated >800°C) this young age implies a later resetting of the I-Xe system by a severe thermal, likely impact-induced, event. The EH impact melt LAP 02225 records a similarly young thermal event. Though no isochron relationship could be established, the data fall within an apparent I-Xe age range of +5 to +15Ma, similar to Sahara 97096. Overall, EH chondrite parent body experienced a thermal history determined by a complex interplay between impact disturbances and parent body metamorphism.

UR - http://www.scopus.com/inward/record.url?scp=84949309509&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84949309509&partnerID=8YFLogxK

U2 - 10.1016/j.gca.2015.11.014

DO - 10.1016/j.gca.2015.11.014

M3 - Article

AN - SCOPUS:84949309509

VL - 174

SP - 196

EP - 210

JO - Geochmica et Cosmochimica Acta

JF - Geochmica et Cosmochimica Acta

SN - 0016-7037

ER -