The end-Triassic mass extinction (ETME) was one of the most severe biotic crises of the Phanerozoic, driven by environmental changes linked to Central Atlantic Magmatic Province volcanism. While the ETME is a well-studied event, its expression in organic-walled phytoplankton, particularly acritarchs, remains relatively unexplored. Palynological analysis of the Prees 2 borehole, NW England (West Midlands), spanning from the upper Rhaetian to the lower Sinemurian, reveals exceptionally diverse aquatic palynomorph assemblages. The aquatic palynological assemblages, in the context of ammonite, miospore and lithostratigraphic data, show how phytoplankton communities responded to stress and subsequent stabilization. In the upper Rhaetian, the dominance of xerophytic coniferous pollen reflects warm, semi-arid palaeoenvironmental conditions, while euryhaline palynomorphs are in a nearshore environment. Subsequent phases show increased terrestrial humidity as evidenced by the palynoflora, coinciding with reduced aquatic diversity in an assemblage adapted to low-oxygen conditions. The base of the Hettangian is marked by sustained Cheirolepidiaceae dominance and a transition from short-spined Micrhystridid occurrences (reflecting low-oxygen conditions) progressing to an increased aquatic morphological diversity phase. This latter phase includes alterations in acritarch assemblages and the proliferation of dinoflagellate cysts, indicating a shift from a proximal shallow-water to a shelf palaeoenvironmental setting. Our findings demonstrate that acritarchs are valuable indicators of palaeoenvironmental change, capturing transient ‘bloom’ phases linked to post-extinction instability and offering new insights into Early Jurassic palaeoecology and recovery following the ETME.

The extent to which continental acidity during the Early Triassic varied with latitude remains insufficiently constrained, despite its relevance for understanding environmental stress and biotic recovery patterns across the Smithian–Spathian boundary (SSB). We examined the abundance, textures and compositions of strontium-rich hydrated aluminium phosphate–sulphate (APS) minerals in 179 continental samples spanning tropical to high paleolatitudes in both hemispheres. APS minerals display broadly comparable early-diagenetic features across sections, indicating formation shortly after deposition under acidic meteoric conditions. Their distribution suggests a latitudinal trend: APS contents commonly exceed 0.1 vol.% in equatorial western peri-Tethyan basins, where faunal and floral records are sparse during the SSB, whereas concentrations decrease towards higher latitudes and are rare beyond ∼40° in both hemispheres. This pattern does not appear to correlate with lithological or textural variability and may reflect spatial differences in the intensity or duration of acidification linked to Siberian Traps volcanism. Equatorial basins thus likely experienced more prolonged or recurrent acidic episodes, whereas higher-latitude areas may have been subject to comparatively attenuated effects, potentially contributing to earlier ecological recovery. These results provide a useful framework for evaluating continental acidification and its environmental implications during the interval following the end-Permian mass extinction (EPME).

The present study investigates the novel occurrence of rare garnet-aluminosilicate-bearing metapelitic enclaves from the Western Lohit Plutonic Complex in the Dibang Valley, Arunachal Pradesh, Northeastern India. Textural, mineralogical, thermobarometric and phase equilibrium modelling analyses reveal a complex polymetamorphic evolution characterized by two distinct stages. The first stage corresponds to a pre-Himalayan low-pressure, high-temperature event likely linked to Cretaceous magmatism, evidenced by relict andalusite porphyroblasts. The second stage reflects Barrovian-type Himalayan metamorphism associated with India-Asia collision, marked by peak assemblages of garnet, kyanite and melt formed near the solidus. Thermobarometric studies estimate near-peak metamorphic conditions at approximately 650 ± 25 °C and 7–9 kbar. Consistently, Pressure-temperature phase equilibrium modelling indicates that garnet core compositions record an initial metamorphic event at lower pressure (∼5.5 kbar) and temperature (∼550 °C), reflecting prograde burial prior to peak conditions. Peak metamorphic conditions, constrained by pressure-temperature phase equilibrium modelling, are estimated at approximately 670 °C and 8.5 kbar. Microstructural observations indicate muscovite-dehydration melting is the primary mechanism for incipient melt generation in the studied metapelite, with the melt largely retained within the rock. Ti-in-biotite thermometry reveals cooling temperatures of 560–590 °C during final exhumation. The rocks experienced a clockwise P–T path involving prograde burial, near-isothermal decompression and retrograde cooling, consistent with thrust duplexing and exhumation along the Lohit thrust shear zone. These findings provide new constraints on the metamorphic evolution and partial melting processes during Himalayan orogenesis in the northern Indo-Burma region.

A 10 m-thick and laterally extensive, mixed siliciclastic–carbonate heterolithic unit occurs between coastal quartz arenites (Banaganapalle Formation) and open marine outer-shelf carbonate platform (Narji Limestone) in the Mesoproterozoic Kurnool sea, India. While the dynamics of mixed siliciclastic–carbonate systems are well studied in the Phanerozoic, comparable Proterozoic examples remain poorly documented and are notably absent from the Indian subcontinent. High-resolution stratigraphic, facies, and petrographic analyses of this heterolithic unit reveal a progressive transition from outer-shelf to storm-dominated middle-to inner-shelf settings, periodically disrupted by episodic high-energy depositional events. Two distinct mixing modes are identified: (i) lithofacies to microscopic-scale strata mixing (Punctuated Mixing), linked to high-frequency sea-level oscillations, and (ii) bed-scale compositional mixing (In-Situ Mixing) of nearshore siliciclastics and subtidal carbonate mud. These findings demonstrate that repeated siliciclastic influx did not inhibit contemporaneous carbonate precipitation, documenting previously unrecognized mixed sedimentation between the Banaganapalle siliciclastics and the Narji carbonates, and advancing understanding of mixed-system dynamics in Proterozoic sedimentary rocks. The widespread occurrence of mixed heteroliths in the Kurnool sub-basin is interpreted to have formed during a phase of rapid subsidence that drove marine transgression, plausibly associated with a rise in sea-level, linked to post-Columbia breakup. Lithostratigraphically correlative heterolithic intervals in the intracratonic Bhima, Pranhita–Godavari and Kurnool basins suggest a regionally extensive, basin-wide Mesoproterozoic transgressive event across the Southern Indian Block. This heterolithic deposit may provide a key stratigraphic marker for regional correlation and yield new insights about the resilience of a Proterozoic non-skeletal carbonate factory and its interaction with episodic siliciclastic input.

The Álamo Complex, part of the Galician–Castilian Lineament within the Central Iberian Zone, lies between the Ollo de Sapo Domain and the Schist–Greywacke Complex. It comprises six tectonometamorphic sectors dominated by psammitic–pelitic metasediments (MTS), gneisses, migmatites, leucogranites and tourmaline-rich rocks. Zircon U–Pb dating identifies three Ediacaran partial melting events (∼628, 584 and 549 Ma) that occurred under high-pressure conditions within the kyanite stability field. These contrast with a low-pressure Variscan partial melting episode (∼310–315 Ma). Orthogneisses and leucogranites dated at ∼482–465 Ma record Cambro–Ordovician magmatism, characterized by abundant inherited Ediacaran zircon cores, indicating significant crustal recycling. Petrographic and geochemical similarities, together with shared zircon inheritance patterns, link the Álamo Complex with the Ollo de Sapo Domain and other segments of the Galician–Castilian Lineament, suggesting a common magmatic evolution. Tourmaline-rich rocks likely formed by boron metasomatism initiated during the Ediacaran and enhanced by recurrent partial melting. Variscan magmatism is represented by intrusive mafic and granitic bodies (∼307–311 Ma) and tourmaline-bearing leucogranites, reflecting continued reworking of Ediacaran crust into the Late Palaeozoic. These results shed light on the crustal evolution of Central Iberia.