Cooling history of atlantis bank oceanic core complex: Evidence for hydrothermal activity 2.6 Ma off axis

Joshua J. Schwartz, Barbara E. John, Michael J. Cheadle, Peter W Reiners, A. Graham Baines

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

We report 26 (U-Th)/He zircon ages from Atlantis Bank, Southwest Indian Ridge, which constrain time scales and rates of lower crustal cooling in ultraslow spreading oceanic crust in this setting. Samples from the detachment fault surface indicate that denuded oceanic crust cooled rapidly (>1 Ma), yielding cooling rates >1200°C/Ma, consistent with existing models for the cooling of oceanic crust. (U-Th)/He zircon ages from samples collected along N-S and E-W trending faults scarps record young ages inconsistent with standard cooling models for lower oceanic crust. These samples have a mean (U-Th)/He zircon age 2.6 Ma younger than their corresponding igneous crystallization ages and record cooling through 200°C well outside the rift valley. Similar anomalously young ages are recorded by zircon, sphene, and apatite fission track data from ODP Hole 735B. We interpret these young ages as recording an off-axis thermal/heating event associated with localized high-temperature (>300°C) hydrothermal fluid flow resulting from underplated mafic magmas.

Original languageEnglish (US)
Article numberQ08020
JournalGeochemistry, Geophysics, Geosystems
Volume10
Issue number8
DOIs
StatePublished - Aug 2009

Fingerprint

hydrothermal activity
histories
Cooling
crusts
cooling
oceanic crust
history
zircon
escarpments
Apatites
apatites
Crystallization
detachment
fluid flow
fission
valleys
detachment fault
Flow of fluids
ridges
titanite

Keywords

  • Core complex
  • Geochronology
  • Thermochronology

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics

Cite this

Cooling history of atlantis bank oceanic core complex : Evidence for hydrothermal activity 2.6 Ma off axis. / Schwartz, Joshua J.; John, Barbara E.; Cheadle, Michael J.; Reiners, Peter W; Baines, A. Graham.

In: Geochemistry, Geophysics, Geosystems, Vol. 10, No. 8, Q08020, 08.2009.

Research output: Contribution to journalArticle

Schwartz, Joshua J. ; John, Barbara E. ; Cheadle, Michael J. ; Reiners, Peter W ; Baines, A. Graham. / Cooling history of atlantis bank oceanic core complex : Evidence for hydrothermal activity 2.6 Ma off axis. In: Geochemistry, Geophysics, Geosystems. 2009 ; Vol. 10, No. 8.
@article{d21e5e27b6c34eaf9815e29da48d523d,
title = "Cooling history of atlantis bank oceanic core complex: Evidence for hydrothermal activity 2.6 Ma off axis",
abstract = "We report 26 (U-Th)/He zircon ages from Atlantis Bank, Southwest Indian Ridge, which constrain time scales and rates of lower crustal cooling in ultraslow spreading oceanic crust in this setting. Samples from the detachment fault surface indicate that denuded oceanic crust cooled rapidly (>1 Ma), yielding cooling rates >1200°C/Ma, consistent with existing models for the cooling of oceanic crust. (U-Th)/He zircon ages from samples collected along N-S and E-W trending faults scarps record young ages inconsistent with standard cooling models for lower oceanic crust. These samples have a mean (U-Th)/He zircon age 2.6 Ma younger than their corresponding igneous crystallization ages and record cooling through 200°C well outside the rift valley. Similar anomalously young ages are recorded by zircon, sphene, and apatite fission track data from ODP Hole 735B. We interpret these young ages as recording an off-axis thermal/heating event associated with localized high-temperature (>300°C) hydrothermal fluid flow resulting from underplated mafic magmas.",
keywords = "Core complex, Geochronology, Thermochronology",
author = "Schwartz, {Joshua J.} and John, {Barbara E.} and Cheadle, {Michael J.} and Reiners, {Peter W} and Baines, {A. Graham}",
year = "2009",
month = "8",
doi = "10.1029/2009GC002466",
language = "English (US)",
volume = "10",
journal = "Geochemistry, Geophysics, Geosystems",
issn = "1525-2027",
publisher = "American Geophysical Union",
number = "8",

}

TY - JOUR

T1 - Cooling history of atlantis bank oceanic core complex

T2 - Evidence for hydrothermal activity 2.6 Ma off axis

AU - Schwartz, Joshua J.

AU - John, Barbara E.

AU - Cheadle, Michael J.

AU - Reiners, Peter W

AU - Baines, A. Graham

PY - 2009/8

Y1 - 2009/8

N2 - We report 26 (U-Th)/He zircon ages from Atlantis Bank, Southwest Indian Ridge, which constrain time scales and rates of lower crustal cooling in ultraslow spreading oceanic crust in this setting. Samples from the detachment fault surface indicate that denuded oceanic crust cooled rapidly (>1 Ma), yielding cooling rates >1200°C/Ma, consistent with existing models for the cooling of oceanic crust. (U-Th)/He zircon ages from samples collected along N-S and E-W trending faults scarps record young ages inconsistent with standard cooling models for lower oceanic crust. These samples have a mean (U-Th)/He zircon age 2.6 Ma younger than their corresponding igneous crystallization ages and record cooling through 200°C well outside the rift valley. Similar anomalously young ages are recorded by zircon, sphene, and apatite fission track data from ODP Hole 735B. We interpret these young ages as recording an off-axis thermal/heating event associated with localized high-temperature (>300°C) hydrothermal fluid flow resulting from underplated mafic magmas.

AB - We report 26 (U-Th)/He zircon ages from Atlantis Bank, Southwest Indian Ridge, which constrain time scales and rates of lower crustal cooling in ultraslow spreading oceanic crust in this setting. Samples from the detachment fault surface indicate that denuded oceanic crust cooled rapidly (>1 Ma), yielding cooling rates >1200°C/Ma, consistent with existing models for the cooling of oceanic crust. (U-Th)/He zircon ages from samples collected along N-S and E-W trending faults scarps record young ages inconsistent with standard cooling models for lower oceanic crust. These samples have a mean (U-Th)/He zircon age 2.6 Ma younger than their corresponding igneous crystallization ages and record cooling through 200°C well outside the rift valley. Similar anomalously young ages are recorded by zircon, sphene, and apatite fission track data from ODP Hole 735B. We interpret these young ages as recording an off-axis thermal/heating event associated with localized high-temperature (>300°C) hydrothermal fluid flow resulting from underplated mafic magmas.

KW - Core complex

KW - Geochronology

KW - Thermochronology

UR - http://www.scopus.com/inward/record.url?scp=70350114699&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=70350114699&partnerID=8YFLogxK

U2 - 10.1029/2009GC002466

DO - 10.1029/2009GC002466

M3 - Article

AN - SCOPUS:70350114699

VL - 10

JO - Geochemistry, Geophysics, Geosystems

JF - Geochemistry, Geophysics, Geosystems

SN - 1525-2027

IS - 8

M1 - Q08020

ER -