Quaternary

The Jiali Fault Zone is one of the key active tectonic structures along the southeastern margin of the Tibetan Plateau and has been widely regarded as the southern boundary structure accommodating the lateral extrusion and eastward escape of the Qiangtang and Sichuan–Yunnan blocks. Assessing its Quaternary activity is important for understanding the tectonic evolution and deformation partitioning of southeastern Tibet. This study focuses on the Yi ong–Zayu segment of the Jiali Fault Zone, using high-resolution stereo imagery from the GF-7 satellite. The ERDAS dense image matching method was applied to generate a dense point cloud and a 0.8 m high-resolution digital surface model. Combining regional remote sensing image interpretation with field surveys, we characterize the geomorphic expression and Quaternary deformation of the Yi ong–Zayu segment. The results show no significant surface displacement along the fault. The alluvial fans are largely preserved, and there are no continuous, co-directional offsets along the tributary channels or river systems. In particular, clear evidence for Quaternary right-lateral strike-slip displacement is absent. Instead, localized normal faults with NW–SE to approximately E–W strikes occur in limited areas. This study focuses on the Yi ong–Zayu segment of the Jiali Fault Zone, using high-resolution stereo imagery from the GF-7 satellite. The ERDAS dense image matching method was applied to generate a dense point cloud and a 0.8 m high-resolution digital surface model. Combining regional remote sensing image interpretation with field surveys, we characterize the geomorphic expression and Qua-ternary deformation of the Yi ong–Zayu segment. The results show no significant surface displacement along the fault. The alluvial fans are largely preserved, and there are no continuous, co-directional offsets along the tributary channels or river systems. In particular, clear evidence for Quaternary right-lateral strike-slip displacement is absent. Instead, localized normal faults with NW–SE to approximately E–W strikes occur in limited areas. These findings indicate that the Yi ong–Zayu segment experienced limited Quaternary deformation and has not functioned as a major boundary strike-slip fault since the Quaternary. Instead, it has been influenced by the rotational extrusion of the southeastern Tibetan Plateau, exhibiting characteristics of regional extensional tectonic activity. The present-day deformation is consistent with a rotation–extrusion model, in which crustal material undergoes clockwise rotation around the eastern Himalayan syntaxis and gradually transfers southeastward toward the Sichuan–Yunnan region due to the obstruction of the rigid Sichuan Basin.

Contourite activity in the Gulf of Cadiz (GoC) is dominated by the precession-driven, ~20 ka cyclicity of the Mediterranean circulation and Mediterranean Outflow Water (MOW). Grain size distributions in contourites are strongly influenced by bottom current speed and are therefore widely used in the GoC to trace past MOW strength changes. However, the influence of sea level changes, driven by the expansion and retreat of ice sheets following the “100 ka world”, is superimposed to some extent through variations in terrigenous sediment supply. Despite the numerous high-resolution proxy records of MOW strength, the influence of glacial–interglacial relative sea level (RSL) changes on these records remains unclear. By analyzing the correlation between sortable silt grain size parameters at IODP U1389, we isolated the grain size variability that is not controlled by bottom current (MOW) sorting. This residual grain size variability closely follows the RSL curves and accounts for the higher sortable silt content observed during RSL lowstands. We suggest that the RSL-induced shoreline proximity contributes to a coarser terrigenous hemipelagic/suspended load component in contourites, increasing silt content. Furthermore, we present novel outflow proxy records based on the specific mineral components by using mica (allogenic) and pyrite (authigenic) counts.

The identification and interpretation of bone surface modifications (BSM) are central to reconstructing early hominin behavior, yet recent shifts by some researchers toward metric quantification face significant epistemological and statistical challenges. This paper critically evaluates the “metric method” proposed by Keevil/Pante et al., arguing that its reliance on continuous, ratio-scale measurements is fundamentally undermined by effector variance—the inherent dimensional mismatch between experimental tools and those in the (assemblage-specific) archaeological record. I demonstrate through statistical analysis that the method’s use of quadratic discriminant analysis (QDA) is compromised by severe multicollinearity (VIF > 5), resulting in unstable models that fail to generalize to fossil contexts, as exemplified by the problematic interpretations of the Grăunceanu (Romania) assemblage. Furthermore, I deconstruct recent critiques against the application of machine learning (ML) in taphonomy, clarifying misconceptions regarding Wolpert’s “no free lunch” theorem and rebutting allegations of data leakage. I contend that ML algorithms, when properly integrated with high-resolution categorical data, provide a more robust and accurate framework for classification of taphonomic datasets. By exposing these methodological biases, I propose a new paradigm for BSM analysis that prioritizes systemic hypothesis testing, objective data generation, and empirical testing/refutation models based on original datasets over speculative arguments and strict metric quantification.