Reply to comment by Z. Yi et al. on “Remagnetization of the Paleogene Tibetan Himalayan carbonate rocks in the Gamba area: Implications for reconstructing the lower plate in the India‐Asia collision”

Abstract

In their comment on our publications on pervasive remagnetization of Jurassic‐Paleogene carbonate rocks of the Tibetan Himalaya (Huang et al., 2017, Journal of Geophysical Research: Solid Earth, 122, doi: 10.1002/2016JB013662 and 122, doi: 10.1002/2017JB013987), Yi et al. (2017) questioned our fold tests applied to their published paleomagenetic results from the Paleogene Zongpu and latest Cretaceous Zongshan carbonate rocks (Patzelt et al., 1996, Tectonophysics, 259(4), 259–284; Yi et al., 2011, Earth and Planetary Science Letters, 309(1), 153–165). They argued that authigenic magnetite pseudomorphic after pyrite, which is the dominant magnetic carrier within these carbonate rocks as indicated by our thorough rock magnetic and petrographic investigations, was formed during early diagenesis and that the primary natural remanent magnetization (NRM) is retained by these carbonate rocks. However, their statement for the invalidity of our fold tests is based on unrealistic assumptions that these carbonate rocks carry primary NRM and that the upper Zongpu Formation was deposited on a 10° primary dip. Their argument for immediate oxidization of pyrite to authigenic magnetite after carbonate deposition onto the continental passive margin ignores that sulfate‐reducing conditions were prevailing during early diagenesis, it is also inconsistent with the timing of the secondary remanence acquisition in remagnetized carbonate rocks elsewhere. As previously demonstrated, and agreed upon by Yi et al. (2017), the Zongpu and Zongshan carbonate rocks in Gamba are remagnetized; here we argue that the timing of remagnetization cannot be demonstrated to shortly postdate sedimentation. These data should therefore not be used for tectonic reconstructions.

A Stable Southern Margin of Asia During the Cretaceous: Paleomagnetic Constraints on the Lhasa‐Qiangtang Collision and the Maximum Width of the Neo‐Tethys

“…Additionally, the limestone data set reported by Chen et al (), which only comprises three sites (22 specimens), is too small and does not permit a test for potential inclination shallowing. Furthermore, the possible remagnetization of limestones from the Tethyan Himalaya compels us to reevaluate the credibility of the results of limestone from the Lhasa terrane (Huang, Lippert, Dekkers, et al, ; Huang, Lippert, Jackson, et al, ; Huang, Lippert, Zhang, et al, ; Yi et al, ).…”

Paleomagnetic Constraints on the India–Asia Collision and the Size of Greater India

“…limestone; Huang, Lippert, Jackson, et al. (2017) further argued that the timing of remagnetization could not be demonstrated to early diagenetic stage, we thus do not use these five paleopoles to constrain the paleolatitudes of the TH. Our new Eocene paleopole (DN) of the Zhepure Fm.…”