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Abstract We present an updated set of Carboniferous Sr, C and O isotope stratigraphies based on the existing literature, given the importance of chemostratigraphy for stratigraphic correlation in the Carboniferous. The Carboniferous⁸⁷Sr/⁸⁶Sr record, constructed using brachiopods and conodonts, exhibits five first-order phases beginning with a rapid decline from a peak value ofc.0.70840 at the Devonian–Carboniferous boundary to a trough (0.70776–0.70771) in the Visean followed by a rise to a plateau (c.0.70827) in the upper Bashkirian. A decline toc.0.70804 follows from the lowermost Gzhelian to the close of the Carboniferous. Contemporaneous carbonate δ¹³C records exhibit considerable variability between materials analysed and by region, although pronounced excursions (e.g. the mid-Tournaisian positive excursion and the end-Kasimovian negative excursion) are present in most records. Bulk carbonate δ¹³C records from South China and Europe, however, are generally consistent with those of brachiopod calcite from North America in terms of both absolute values and trends. Both brachiopod calcite and conodont phosphate δ¹⁸O document large regional variability, confirming that Carboniferous δ¹⁸O records are invalid for precise stratigraphic correlation. Nevertheless, significant positive δ¹⁸O shifts in certain intervals (e.g. mid-Tournaisian and the Mississippian–Pennsylvanian transition) can be used for global correlation. 

Responsive chromic materials are highly desirable in the fields of displays, anti-counterfeiting, and camouflage, but their advanced applications are usually limited by the unrealized delicate and independent tunability of their three intrinsic attributes of color. This work achieves the separate, continuous, and reversible modulation of structural color brightness and hue with an aqueous suspension of dual-responsive Fe 3 O 4 @polyvinylpyrrolidone (PVP)@poly( N -isopropyl acrylamide) (PNIPAM) flexible photonic nanochains. The underlying modulation mechanism of color brightness was experimentally and numerically deciphered by analyzing the morphological responses to stimuli. When an increasing magnetic field was applied, the random worm-like flexible photonic nanochains gradually orientated along the field direction, due to the dominant magnetic dipole interaction over the thermal motion, lengthening the orientation segment length up to the whole of the nanochains. Consequently, the suspension displays increased color brightness (characterized by diffraction intensity). Meanwhile, the color hue (characterized by diffraction frequency) could be controlled by temperature, due to the volume changes of the interparticle PNIPAM. The achieved diverse color modulation advances the next-generation responsive chromic materials and enriches the basic understanding of the color tuning mechanisms. With versatile and facile color tunability and shape patterning, the developed responsive chromic liquid promises to have attractive potential in full-color displays and in adaptive camouflages. 

Piecing together the history of carbon (C) perturbation events throughout Earth’s history has provided key insights into how the Earth system responds to abrupt warming. Previous studies, however, focused on short-term warming events that were superimposed on longer-term greenhouse climate states. Here, we present an integrated proxy (C and uranium [U] isotopes and paleo CO 2 ) and multicomponent modeling approach to investigate an abrupt C perturbation and global warming event (∼304 Ma) that occurred during a paleo-glacial state. We report pronounced negative C and U isotopic excursions coincident with a doubling of atmospheric CO 2 partial pressure and a biodiversity nadir. The isotopic excursions can be linked to an injection of ∼9,000 Gt of organic matter–derived C over ∼300 kyr and to near 20% of areal extent of seafloor anoxia. Earth system modeling indicates that widespread anoxic conditions can be linked to enhanced thermocline stratification and increased nutrient fluxes during this global warming within an icehouse. 

Earth’s penultimate icehouse (ca. 340–285 Ma) was a time of low atmospheric pCO2 and high pO2, formation of the supercontinent Pangaea, dynamic glaciation in the Southern Hemisphere, and radiation of the oldest tropical rainforests. Although it has been long appreciated that these major tectonic, climatic, and biotic events left their signature on seawater 87Sr/86Sr through their influence on Sr fluxes to the ocean, the temporal resolution and precision of the late Paleozoic seawater 87Sr/86Sr record remain relatively low. Here we present a high-temporal-resolution and high-fidelity record of Carboniferous– early Permian seawater 87Sr/86Sr based on conodont bioapatite from an open-water carbonate slope succession in south China. The new data define a rate of long-term rise in 87Sr/86Sr (0.000035/m.y.) from ca. 334–318 Ma comparable to that of the middle to late Cenozoic. The onset of the rapid decline in 87Sr/86Sr (0.000043/m.y.), following a prolonged plateau (318–303 Ma), is constrained to ca. 303 Ma. A major decoupling of 87Sr/86Sr and pCO2 during 303–297 Ma, coincident with the Paleozoic peak in pO2, widespread low-latitude aridification, and demise of the pan-tropical wetland forests, suggests a major shift in the dominant influence on pCO2 from continental weathering and organic carbon sequestration (as coals) on land to organic carbon burial in the ocean. 

Abstract Subaqueous mass‐transport processes are one of the mechanisms for transport of sediment into the deep sea. Internal structures and depositional processes of carbonate mass‐transport deposits are relatively poorly understood relative to siliciclastic facies due to their comparative paucity in the rock record. A variety of carbonate mass‐transport deposits, including slumps, debrites and deep‐channel‐confined density flow deposits, occur in Middle–Upper Ordovician slope deposits in western Inner Mongolia (Wuhai), China. These provide a rare opportunity to illustrate the emplacement history of carbonate mass‐transport deposits at the outcrop scale. The slumps and debrites host remarkable folds, chaotic beds and imbricated beds that reflect differences in both rheology and position on the slope. Individual slump sheets show gradations between undulating laminae, inclined and recumbent folds, highly deformed folds, and chaotic textures upslope from the toe region. Debrites are commonly interbedded with slump deposits, whereas imbricated beds are present in the middle and lower parts of the toes of slump sheets near the terminal wall. In the study area, thin‐bedded limestone with slump deposits of the Kelimoli Formation are overlain by fine‐grained, siliciclastic‐dominated, slope deposits of the Wulalike Formation. A thick breccia of the Wulalike Formation was deposited in a main feeder channel in south‐east Wuhai, but to the west‐north‐west the breccia was deposited in distributary channels possibly represented as a unique lower‐slope pattern of gullies. At the latter locality, the breccia was deposited solely within the channels on a steep west‐north‐west dipping slope under density‐driven flows. The mass‐transport deposits documented herein records passive to foreland basin tectonic transitions, and associated platform foundering and steepening of the slope. A slope facies model was constructed to demonstrate the spatial and temporal variations of mass‐transport deposits during basin evolution, and as such it provides a template for the interpretation of the deposits of ancient slopes that underwent passive to active tectonic transitions.