TY - JOUR
T1 - PbSL dating of garnet and staurolite
T2 - constraints on the Paleoproterozoic crustal evolution of the Eastern Block, North China Craton
AU - Xie, Lie-Wen
AU - Yang, Jin-Hui
AU - Wu, Fu-Yuan
AU - Yang, Yue-Heng
AU - Wilde, Simon A.
PY - 2011/7/10
Y1 - 2011/7/10
N2 - It is well accepted that the North China Craton formed by assembly of the Eastern and Western blocks along the Trans-North China Orogen, with cratonization in the Paleoproterozoic (~1.85Ma). However, there is controversy about the formation of the Eastern and Western blocks themselves, especially the timing of cratonization of the Eastern Block. The Jiao-Liao-Ji orogenic belt is the most important Paleoproterozoic Orogenic belt in the Eastern Block and consists mainly of the North and South Liaohe Groups and the Liaoji Granitoids. The timing of metamorphism of the Liaohe Group is the key to understanding the evolution of the Eastern Block of the North China Craton. Because the isotope systematics of metamorphic minerals can be used to date parts of the prograde thermal histories of metamorphic belts, dating of minerals, such as garnet and staurolite has the distinct advantage that time information can be related directly to the pressure-temperature-deformation history recorded by the same mineral. In this paper we present results of precise 207Pb/206Pb stepwise-leaching (PbSL) dating of garnet and staurolite from the metasedimentary rocks of the south Liaohe Group. The primitive Pb and radiogenic Pb are selectively extracted from garnet and straurolite by leach steps and determined by multiple collector (MC-) ICP-MS. The garnet and staurolite record two groups of 207Pb/206Pb ages, at 1.93-1.91Ga and ~1.86Ga, respectively. These constrain the time of peak metamorphism of the Liaohe Group during collision between the Longgang Block in the north and the Liaonan (Nangrim) Block in the south and a subsequent post-collisional event, respectively. Our data for the South Liaohe Group and previously published data for the Liaoji Granite, combined with key lithological, structural and metamorphic information, indicate that the cratonization of the Eastern Block of the North China Craton occurred at 1.93-1.91Ga.
AB - It is well accepted that the North China Craton formed by assembly of the Eastern and Western blocks along the Trans-North China Orogen, with cratonization in the Paleoproterozoic (~1.85Ma). However, there is controversy about the formation of the Eastern and Western blocks themselves, especially the timing of cratonization of the Eastern Block. The Jiao-Liao-Ji orogenic belt is the most important Paleoproterozoic Orogenic belt in the Eastern Block and consists mainly of the North and South Liaohe Groups and the Liaoji Granitoids. The timing of metamorphism of the Liaohe Group is the key to understanding the evolution of the Eastern Block of the North China Craton. Because the isotope systematics of metamorphic minerals can be used to date parts of the prograde thermal histories of metamorphic belts, dating of minerals, such as garnet and staurolite has the distinct advantage that time information can be related directly to the pressure-temperature-deformation history recorded by the same mineral. In this paper we present results of precise 207Pb/206Pb stepwise-leaching (PbSL) dating of garnet and staurolite from the metasedimentary rocks of the south Liaohe Group. The primitive Pb and radiogenic Pb are selectively extracted from garnet and straurolite by leach steps and determined by multiple collector (MC-) ICP-MS. The garnet and staurolite record two groups of 207Pb/206Pb ages, at 1.93-1.91Ga and ~1.86Ga, respectively. These constrain the time of peak metamorphism of the Liaohe Group during collision between the Longgang Block in the north and the Liaonan (Nangrim) Block in the south and a subsequent post-collisional event, respectively. Our data for the South Liaohe Group and previously published data for the Liaoji Granite, combined with key lithological, structural and metamorphic information, indicate that the cratonization of the Eastern Block of the North China Craton occurred at 1.93-1.91Ga.
KW - Eastern Block
KW - North China Craton
KW - Liaohe Group
KW - Jiao-Liao-Ji belt
KW - Pb step-leaching dating
KW - garnet
KW - staurolite
UR - http://www.scopus.com/inward/record.url?scp=79959298806&partnerID=8YFLogxK
U2 - 10.1016/j.jseaes.2011.04.016
DO - 10.1016/j.jseaes.2011.04.016
M3 - Article
VL - 42
SP - 142
EP - 154
JO - Journal of Asian Earth Sciences
JF - Journal of Asian Earth Sciences
SN - 1367-9120
IS - 1-2
ER -