TY  - JOUR
A1  - Huang, Wentao
A1  - van Hinsbergen, Douwe J. J.
A1  - Maffione, Marco
A1  - Orme, Devon A.
A1  - Dupont-Nivet, Guillaume
A1  - Guilmette, Carl
A1  - Ding, Lin
A1  - Guo, Zhaojie
A1  - Kapp, Paul
T1  - Lower Cretaceous Xigaze ophiolites formed in the Gangdese forearc: Evidence from paleomagnetism, sediment provenance, and stratigraphy
JF  - Earth & planetary science letters
N2  - The India-Asia suture zone of southern Tibet exposes Lower Cretaceous Xigaze ophiolites and radiolarian cherts, and time-equivalent Asian-derived clastic forearc sedimentary rocks (Xigaze Group). These ophiolites have been interpreted to have formed in the forearc of the north-dipping subduction zone below Tibet that produced the Gangdese magmatic arc around 15-20 degrees N, or in the forearc of a subequatorial intra-oceanic subduction zone. To better constrain the latitude of the ophiolites, we carried out an integrated paleomagnetic, geochronologic and stratigraphical study on epi-ophiolitic radiolarites (Chongdui and Bainang sections), and Xigaze Group turbiditic sandstones unconformably overlying the ophiolite's mantle units (Sangsang section). Detrital zircon U-Pb geochronology of tuffaceous layers from the Chongdui section and sandstones of the Xigaze Group at the Sangsang section provides maximum depositional ages of 116.5 +/- 3.1 Ma and 128.8 +/- 3.4 Ma, respectively, for the Chongdui section and an Asian provenance signature for the Xigaze Group. Paleomagnetic analyses, integrated with rock magnetic experiments, indicate significant compaction-related inclination 'shallowing' of the remanence within the studied rocks. Two independent methods are applied for the inclination shallowing correction of the paleomagnetic directions from the Sangsang section, yielding consistent mean paleolatitudes of 16.2 degrees N 113 degrees N, 20.9 degrees N] and 16.8 degrees N [11.1 degrees N, 23.3 degrees N], respectively. These results are indistinguishable from recent paleolatitude estimates for the Gangdese arc in southern Tibet. Radiolarites from the Chongdui and Bainang sections yield low paleomagnetic inclinations that would suggest a sub-equatorial paleolatitude, but the distribution of the paleomagnetic directions in these rocks strongly suggests a low inclination bias by compaction. Our data indicate that spreading of the Xigaze ophiolite occurred in the Gangdese forearc, and formed the basement of the forearc strata. (C) 2015 Elsevier B.V. All rights reserved.
KW  - Xigaze ophiolite
KW  - sedimentary contact
KW  - paleomagnetism and rock magnetism
KW  - inclination shallowing
Y1  - 2015
U6  - https://doi.org/10.1016/j.epsl.2015.01.032
SN  - 0012-821X
SN  - 1385-013X
VL  - 415
SP  - 142
EP  - 153
PB  - Elsevier
CY  - Amsterdam
ER  -