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Cenozoic Exhumation of Larsemann Hills, East Antarctica: Evidence from Apatite Fission‐track Thermochronology
Author(s) -
CHEN Xuanhua,
JIANG Rongbao,
WAN Jinglin,
XU Gang,
JIANG Mei,
CHEN Danhong
Publication year - 2010
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/j.1755-6724.2010.00142.x
Subject(s) - geology , fission track dating , cenozoic , paleontology , tectonics , mesozoic , geochemistry , earth science , structural basin
Does Cenozoic exhumation occur in the Larsemann Hills, East Antarctica? In the present paper, we conducted an apatite fission‐track thermochronologic study across the Larsemann Hills of East Antarctica. Our work reveals a Cenozoic exhumation event at 49.8 ± 12 Ma, which we interpret to be a result of exhumation caused by crustal extension. Within the uncertainty of our age determination, the timing of extension in East Antarctica determined by our study is coeval with the onset time of rifting in West Antarctica at c.55 Ma. The apatite fission‐track cooling ages vary systematically in space, indicating a coherent block rotation of the Larsemann Hills region from c.50 Ma to c.10 Ma. This pattern of block tilting was locally disrupted by normal faulting along the Larsemann Hills detachment fault at c.5.4 Ma. The regional extension in the Larsemann Hills, East Antarctica was the result of tectonic evolution in this area, and may be related to the global extension. Through the discussion of Pan‐Gondwanaland movement, and Mesozoic and Cenozoic extensions in West and East Antarctica and adjacent areas, we suggest that the protracted Cenozoic cooling over the Larsemann Hills area was caused by extensional tectonics related to separation and formation of the India Ocean at the time of Gondwanaland breakup.