Quaternary Fluvial Terraces as Markers of Climate and Tectonics in the Bradanic Foredeep, Southern Italy

Tectono‐Stratigraphic Evolution of a Shared Foreland Basin: A 3D Geomodel and Detrital Flux Reconstruction for the Pliocene‐Pleistocene of the Po‐Plain Basin (Northern Italy)

The Po Plain Basin represents the shared foreland system of the Southern Alps and Northern Apennines belts, holding significant importance for geological research and energy resource management. We present a new basin‐scale 3D geomodel of the Pliocene‐Pleistocene succession, interpreted from an extensive dataset of seismic lines and well logs spanning the entire basin. This high‐resolution model enables a detailed, quantitative analysis of tectonic deformation timing and sediment flux over the last 5 My. Analysis of the isobath and isochore maps documents that the Northern Apennines collision with the Southern Alps began in the early Pliocene, subsequently leading to the sequential fragmentation of the central foredeep into three distinct depocenters. Quantitative decompaction analysis revealed a very significant increase in sediment flux in the basin during the mid‐Pleistocene despite a widespread decrease in tectonic activity. We propose that this increase was climate‐driven, due to the combined effect of high‐frequency, high‐amplitude climate cyclicity predating the onset of major glaciations in the Alps and amplifying sediment supply. This work opens new questions about the age of transition from fluvial to glacial‐dominated erosion in the Alps, and provides a new, quantitative tectono‐sedimentary framework for the Po Plain, useful for better understanding the basin dynamics and consequent architecture.

Hydraulic and Sedimentological Reconstruction of a Middle/Late Pleistocene Boundary Superflood (Ebro River, NE Iberian Peninsula)

Fluvial superfloods are geomorphologically significant episodes due to their enormous energy and extremely low recurrence in the geological record. Their rarity is particularly notable in areas far from the major continental glacial masses. Hydraulic constrictions in the Lower Ebro River gorges caused the accumulation of fluvial deposits, as floodwaters from the Ebro River were forced upstream into the tributary valleys of the Móra Basin. The most illustrative example is the Comte Creek, where two depositional units of different ages show upstream flood accumulations (extending up to ~4 km) with very high-energy sedimentary structures, followed by downstream reworking during backflow. Two-dimensional hydraulic simulations indicate that peak discharges reaching 385,000 m3·s−1, with water depths of approximately 28 m in the confluence area, would have been required to transport sediments to the observed outcrop positions. Luminescence dating of the slackwater deposits indicates that the formative processes occurred during the latest Middle Pleistocene or the Last Interglacial (Eemian).

Geochronological, Geomorphological, and Sedimentary Evidence for the Repeated Formation of Large Late Pleistocene Ice-Dammed Lakes in Southeastern Altai

Flexural tectonics and lithological controls on landscape evolution in a forebulge region: Insights from Central India

Forebulge regions represent slowly deforming intraplate settings where the relative roles of flexural tectonics, lithological variability and climate in shaping landscapes remain poorly constrained. We investigate the Central Indian Forebulge (CIF), which formed in response to Himalayan loading and despite low erosion rates (2–7 m/Myr), hosts widespread transient landforms, including waterfalls, canyons and escarpments that are generally associated with tectonically active settings. To evaluate the controls on landscape evolution in CIF, we integrate morphometric analyses (normalized channel steepness index ksn, chi profiles), catchment‐averaged cosmogenic 10Be erosion rates, field‐based rock strength measurements, lineament and stream orientation analysis, and flexural stress modelling. Our results show that flexural tectonics exerts a primary control on landscape organization through the generation of fracture networks that guide rivers. Modelled fibre stress magnitudes on the CIF exceed 14.2 MPa, which is sufficient to overcome the tensile strength of the lithologies present on the forebulge. These stresses are enough to generate and reactivate extensional fracture networks associated with flexural uplift. Stream orientations and lineament trends show a dominant NW–SE direction, which aligns with forebulge‐parallel fracture systems. The majority of structurally controlled knickpoints also align with these NW–SE lineaments. The ksn values are broadly similar across lithologies in spite of their different rock strengths (uniaxial compression strength range, 16–199 MPa), indicating that channel steepness does not relate directly with substrate erodibility at basin scale. Erosion rates show positive relationships with basin‐averaged slope, relief and ksn but weak relationships with precipitation and drainage area, suggesting that denudation is largely governed by the topographic gradients established under long‐term tectonic forcing. These observations indicate that flexural tectonics controls the structural framework and topographic boundary conditions for river incision, whereas lithological contrasts modulate erosion efficiency and the expression of transient landforms. The weak coupling between channel steepness and lithologic erodibility demonstrates that the CIF represents a transient landscape that is not yet in steady state.

Glaciation-tectonic coupling: Stabilizing the southeastern Tibetan Plateau

Why rivers have not deeply incised the interior of the Tibetan Plateau over geologic time scales remains an open question. Resolving this issue requires clarifying and quantifying the respective influences of different geological factors on headward river erosion. Focusing on the Eastern Himalayan syntaxis, we reveal that glacial damming occurred frequently along an ∼70 km reach of the Yarlung Tsangpo River, based on 10Be exposure dating and paleoglacial modeling. Glacial-damming episodes limited headward erosion via a cycle in which prolonged damming inhibited erosion during glacial periods and short-lived damming delayed it during interglacial periods. Moreover, these damming processes triggered extensive aggradation upstream and protected bedrock from erosion over long time scales, while they enhanced downstream incision, reshaping the longitudinal profile of the Yarlung Tsangpo River. Repeated glacial-damming processes cumulatively raised the effective local base level by ∼300 m since the middle Pleistocene. Overall, we show that the coupling of glaciation and tectonics is the key factor maintaining the long-term stability of the southeastern Tibetan Plateau margin.

Anastomosing fluvial sedimentation in a foreland basin: paleoclimatic and tectonic controls on the Middle Eocene Gercus Formation, Kurdistan Region, northeastern Iraq

Integrated sedimentological, petrographic, mineralogical, and facies studies of the Gercus Formation reveal a tectonically influenced fluvial depositional environment responding to changing paleoclimate. Modal QFL analysis indicates a lithic-rich framework with subangular grains and low textural maturity, suggesting a proximal derivation from heterogeneous volcanic-plutonic-metamorphic-sedimentary source terrains, associated with limited transport reworking and reduced levels of chemical weathering consistent with foreland basin depositional settings. Polymictic assemblages of lithics suggest a provenance with a tectonically active and high rate of accumulation. XRD results exhibit palygorskite-dolomite patterns suggesting that the authigenic minerals present indicate a seasonal water-deficient environment with the existence of intermittent moisture. The accumulated clay mineral distributions document successive diagenetic modifications where shallow-buried sediments keep the primary illite-chlorite assemblages extracted from the physical weathering of metamorphic-igneous terranes, compared to deeply buried rock units that experienced a complete mineralogical conversion. Lateral mineralogical changes – hematite increase (northeastern Iraq – Khalakan) versus graphite accumulation (northeastern Iraq – Merade), indicate redox-limited facies successions from poorly drained floodbasin to well-drained interchannel settings. The micritic groundmass of calcareous palaeosol horizons shows local concentrations of microspar, indicating episodic water table depth (WTD) fluctuations and high evapotranspiration under a semi-arid climate with seasonally interrupted soil moisture. Six architectural elements (CH, SB, LV, CC, CS, and FF) define an anastomosing fluvial system with widespread floodplain aggradation and common crevasse channel-splay development. The existence of this architectural system, associated with calcareous pedogenic horizons, conclusively demonstrates low-gradient floodplain settings under climatic regimes varying seasonally from arid to semi-arid conditions.