Examples of tectonic overprints of magnetic fabrics in rocks of the Bohemian Massif and Western Carpathians

Reply to Comment by Zhao et al. on “Paleomagnetism of the Late Cretaceous Red Beds From the Far Western Lhasa Terrane: Inclination Discrepancy and Tectonic Implications”

“…In addition, the value of corrected AMS degree (P j ) is relatively small (1.025 and 1.021 for the northern and southern limbs of folds, respectively), and AMS results display both oblate and prolate ellipsoids (Figures 3c, 3d, 3g, and 3h in Bian et al (2020)). These features are clearly inconsistent with stage 5 (strong cleavage) which are dominated by oblate ellipsoids and higher value of P j (Figure 2 in Hrouda & Chadima, 2020). The AMS deformed characteristics of the samples from Bian et al's (2020) Jingzhushan Formation red beds should belong to stage 2 (incipient deformation) to stage 4 (weak cleavage), which is also consistent with weak and moderate deformed magnetic fabrics (Weil & Yonkee, 2009).…”

“…(2020)). These features are clearly inconsistent with stage 5 (strong cleavage) which are dominated by oblate ellipsoids and higher value of P j (Figure 2 in Hrouda & Chadima, 2020). The AMS deformed characteristics of the samples from Bian et al.’s (2020) Jingzhushan Formation red beds should belong to stage 2 (incipient deformation) to stage 4 (weak cleavage), which is also consistent with weak and moderate deformed magnetic fabrics (Weil & Yonkee, 2009).…”

“…AMS analyses indicate that the Late Cretaceous‐Eocene red beds have subjected to northeast‐southwestward compression (Li, van Hinsbergen, Shen, et al., 2020; Zhang et al., 2018). According to the classification of AMS results proposed by Hrouda and Chadima (2020), their deformed characteristics should belong to stage 2 (incipient deformation) to stage 4 (weak cleavage). Noticeably, magnetostratigraphic results revealed multiple normal and reversed magnetozones (Bain et al., 2020; Li et al., 2020), which, combined with positive fold and reversal tests, suggests that the ChRM directions obtained from the Late Cretaceous‐Eocene red beds of the Gonjo basin are primary magnetization acquired before folding (Huang et al., 2020; Li, van Hinsbergen, Najman, et al., 2020; Tong, Yang, Mao, et al., 2017).…”

Structural analysis of the foreland basin of the southern Longmenshan tectonic belt: New insights from magnetic fabrics

“…The tensor defining AMS can be visualized as an ellipsoid where the orthogonal axes correspond to K max , K min , and K int , respectively (Tarling & Hrouda, 1993). In general, a close correspondence exists between the principal axes of magnetic susceptibility ellipsoid and that of strain ellipsoid (Figure 1), showing coaxial and a certain quantitative relationship in size (Almqvist, Hirt, Schmidt, & Dietrich, 2009;Borradaile & Tarling, 1981;Hrouda, 1982;Hrouda & Chadima, 2019; J. X. Li et al, 2020).…”

Comment on “Paleomagnetism of the Late Cretaceous Red Beds From the Far Western Lhasa Terrane: Inclination Discrepancy and Tectonic Implications” by Bian et al.

“…As the AMS analysis shown in Figure 3 of Bian et al (2020), the K min axes of the southern limb are distributed along an embryonic girdle that is parallel to the shortening, while the K max axes of the northern limb remain perpendicular to the shortening and the K min axes conspicuously extend along the direction that is parallel to the slaty cleavage. The deformation of rocks can be progressively classified into 6° referring to different AMS results (Hrouda & Chadima, 2020;Parés, 2015). Accordingly, the magnetic fabrics shown in Bian et al (2020) display characteristics of deformation degree 3 (pencil structure) to degree 5 (strong cleavage), which are determined by the competition of the layer parallel shearing ZHAO ET AL.…”