TY - JOUR
T1 - Preliminary early cretaceous paleomagnetic results from the Gansu Corridor, China
AU - Frost, Gina Marie
AU - Coe, Robert S.
AU - Meng, Zifang
AU - Peng, Zuolin
AU - Chen, Yan
AU - Courtillot, Vincent
AU - Peltzer, Gilles
AU - Tapponnier, Paul
AU - Avouac, Jean Philippe
PY - 1995/1
Y1 - 1995/1
N2 - We report results from our paleomagnetic study of Lower Cretaceous redbeds from the Gansu Corridor, northwestern China. The characteristic remanent magnetization (ChRM) resides in hematite, often at very high unblocking temperatures (> 660°C). The directions associated with this component exhibit only reversed polarities from locality A (Sunan area), but the samples from locality B (Lanzhou area, 480 km to the southeast) show roughly antipodal normal and reversed polarities. The combined sample directional data from both localities pass a fold test at the 99% confidence level. The mean paleomagnetic pole is located at 48.7°N, 199.7°E, with A95 = 4.1°, which is discordant with poles of similar age elsewhere from neighboring regions in China. Although represented by relatively few samples (N = 21) this pole suggests that significant post-Cretaceous motion may have occurred between the Gansu Corridor and adjacent blocks. Relative to Eurasia or North China, the discordance corresponds to 28.1 ± 5.2° or 35.6° ± 9.7° clockwise rotation and 9.5° ± 4.5° or 9.8° ± 8.2° northward displacement respectively. The rotations support, but do not yet distinguish between, several neotectonic models assumed to have acted over the past 15-40 m.y. The displacement is not predicted by any of these models; if real, it may have occurred early in the history of the India-Asia collision, or even before.
AB - We report results from our paleomagnetic study of Lower Cretaceous redbeds from the Gansu Corridor, northwestern China. The characteristic remanent magnetization (ChRM) resides in hematite, often at very high unblocking temperatures (> 660°C). The directions associated with this component exhibit only reversed polarities from locality A (Sunan area), but the samples from locality B (Lanzhou area, 480 km to the southeast) show roughly antipodal normal and reversed polarities. The combined sample directional data from both localities pass a fold test at the 99% confidence level. The mean paleomagnetic pole is located at 48.7°N, 199.7°E, with A95 = 4.1°, which is discordant with poles of similar age elsewhere from neighboring regions in China. Although represented by relatively few samples (N = 21) this pole suggests that significant post-Cretaceous motion may have occurred between the Gansu Corridor and adjacent blocks. Relative to Eurasia or North China, the discordance corresponds to 28.1 ± 5.2° or 35.6° ± 9.7° clockwise rotation and 9.5° ± 4.5° or 9.8° ± 8.2° northward displacement respectively. The rotations support, but do not yet distinguish between, several neotectonic models assumed to have acted over the past 15-40 m.y. The displacement is not predicted by any of these models; if real, it may have occurred early in the history of the India-Asia collision, or even before.
UR - http://www.scopus.com/inward/record.url?scp=0028792819&partnerID=8YFLogxK
U2 - 10.1016/0012-821X(94)00244-S
DO - 10.1016/0012-821X(94)00244-S
M3 - Article
AN - SCOPUS:0028792819
SN - 0012-821X
VL - 129
SP - 217
EP - 232
JO - Earth and Planetary Science Letters
JF - Earth and Planetary Science Letters
IS - 1-4
ER -