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Abstract Pattern formation driven by mechanical stress plays a fundamental role in shaping structural organization in both natural and human-made systems. Using light as a vectorial stimulus may offer a powerful route to control stress-induced pattern formation in materials. However, achieving localized, programmable, and predictable control of individual microstructures via structured polarization fields has remained a major challenge. Here, we introduce vectorial field-guided lithography, a novel approach that leverages fully structured polarization fields as lithographic tools to enable the stress-driven reconfiguration of pre-patterned azopolymer microstructures with an unprecedented degree of flexibility, complexity, and diversity. By building on the Viscoplastic PhotoAlignment model, which describes the azopolymer deformation as a stress response to structured light, we quantitatively demonstrate and predict complex surface architectures generated by programmable light-induced stress pathways using a digital polarization rotator implemented via a spatial light modulator. We model and experimentally achieve single-step formation of anisotropic, bent, and chiral microstructures from a single pre-patterned geometry. Our results reveal an exceptional control over local microstructure morphology and establish, for the first time, a comprehensive theoretical framework capable of quantitatively designing and fabricating target morphologies on azopolymers. This work moves beyond conventional intensity-based photopatterning and demonstrates that the full vectorial nature of light can dictate the mechanical reshaping of functional polymer surfaces, providing a new platform for the programmable design of complex microarchitectures with applications in photonics, microfluidics, and biology. 

A maskless single beam process for photofabrication of surface microstructures is reported. A continuously moving azopolymer film is illuminated with structured polarized light from a 488 nm laser and spatial light modulator, driving the formation of surface relief gratings in real time. The structures were replicated using nanoimprint lithography, and exhibited a maximum diffraction efficiency of order 30% at 633 nm. Using the period tunability of the spatial light modulator, surface gratings were fabricated that diffract red, green, and blue light along a common direction, illustrating the potential of this fabrication platform in the field of structured color. 

Abstract Great Salt Lake (GSL), Utah, USA, is a large hypersaline lake, but during short‐lived (∼10–20 kyr) pluvials, it was an expansive freshwater lake. We update the age model of GLAD1‐GSL00‐4, a 120‐m sediment core recovered by the Global Lakes Drilling (GLAD) project, with new U‐series measurements dating evaporites representing the driest times in lake history and providing a new basal age of 236.3 ka (2σuncertainty = 6.7 kyr) during the penultimate interglacial. We measure microbial membrane lipid abundances, dialkyl glycerol diethers and glycerol dialkyl glycerol tetraethers (GDGT), to reconstruct salinity over the last two glacial cycles. High and variable salinity precludes use of GDGTs as a proxy for temperature. The freshwater, deep, expanded lake phases “Bonneville” and “Little Valley,” here dated to 30.3–16.1 ka (2σ = 1.0–1.4 kyr) and 140.4–134.6 ka (2σ = 5.5–5.7 kyr) respectively, occur during deglacial pluvials and briefly interrupt the hypersaline conditions which dominate the record. The salinity rise following the last pluvial agrees with water balance reconstructions from well‐dated lacustrine carbonates. However, evaporite (thenardite) deposition dated to 16.1–12.2 ka (2σ = 0.8–1.0 kyr) contrasts with Holocene timing elsewhere in the basin. After the Little Valley highstand, a salinity increase culminates in halite precipitation. Despite four disparate halite dates spanning 90–160 ka, age model assignment agrees with U‐series dating of Little Valley shoreline tufa. This continuous salinity record provides context for lake expansion/contraction followed by evaporite deposition across two glacial terminations, consistent with regional pluvials. 

Abstract The Malagasy Summer Monsoon is an important part of the larger Indian Ocean and tropical monsoon region. As the effects of global warming play out, changes to precipitation in Madagascar will have important ramifications for the Malagasy people. To help understand how precipitation responds to climate changes we present a long-term Holocene speleothem record from Anjohibe, part of the Andranoboka cave system in northwestern Madagascar. To date, it is the most complete Holocene record from this region and sheds light on the nature of millennial and centennial precipitation changes in this region. We find that over the Holocene, precipitation in northwestern Madagascar is actually in phase with the Northern Hemisphere Asian monsoon on multi-millennial scales, but that during some shorter centennial-scale events such as the 8.2 ka event, Anjohibe exhibits an antiphase precipitation signal to the Northern Hemisphere. The ultimate driver of precipitation changes across the Holocene does not appear to be the meridional migration of the monsoon. Instead, zonal sea surface temperature gradients in the Indian Ocean seem to play a primary role in precipitation changes in northwestern Madagascar. 

Northwest Africa transitioned from a wet/vegetated landscape toward drier/sparser conditions sometime between the late‐Pliocene and the late‐Pleistocene. However, our understanding of the precise timing and nature of this transition is hampered by a paucity of paleo‐records which bridge these two intervals. Here we report new plant‐wax isotope as well as dust and opal flux records from the relatively brief interval ∼1.1–1.0 million years ago (Ma) to evaluate the astronomical timescale controls of Northwest African hydroclimate and vegetation during the Mid‐Pleistocene Transition (MPT) and, in context with published records, the drivers of long‐term climate and ecological trends over the Plio‐Pleistocene. The tempo and amplitude of the Northwest African monsoon rainfall swings closely track low latitude insolation forcings over the last 5 Ma. However, we demonstrate that a pronounced mean state decline in monsoon strength likely occurred following the MPT most likely instigated by increasing Atlantic meridional sea surface temperature gradients or declines in the strength of the meridional overturning circulation. The northward extent of vegetation does not track changes in monsoon strength over the Plio‐Pleistocene and thus may be more strongly influenced by changes in monsoon rainfall extent or ecosystem disturbances. Progressively diminished dust fluxes following a decline in monsoon strength after 1.0 Ma is consistent with reduced production and subsequent depletion of fine‐grained sediments in the Sahara. Synchroneity between dust and opal fluxes across timescales suggests nutrient delivery to the surface ocean via dust plays a key role in marine primary productivity off the coast of Northwest Africa.