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1. Evaluating the relationship between the area and latitude of large igneous provinces and Earth’s long-term climate state. In Large Igneous Provinces: A Driver of Global Environmental and Biotic Changes

   https://doi.org/DOI: 10.1002/9781119507444.ch7  

   Park, Y. (January 2021, Geophysical monograph)

   Ernst, R.E. (Ed.)

   One of the hypothesized effects of large igneous provinces (LIPs) is planetary cooling on million-year timescales associated with enhanced silicate weathering of freshly emplaced basalt. This study combines reconstructions of the original surface extent and emplacement ages of LIPs, a paleogeographic model, and a parameterization of LIP erosion to estimate LIP area in all latitudinal bands through the Phanerozoic. This analysis reveals no significant correlation between total LIP area, nor LIP area in the tropics, and the extent of continental ice sheets. The largest peaks in tropical LIP area are at times of non-glacial climate. These results suggest that changes in planetary weatherability associated with LIPs are not the fundamental control on whether Earth is in a glacial or non-glacial climate, although they could provide a secondary modulating effect in conjunction with other processes. 

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2. The Franklin Large Igneous Province and Snowball Earth Initiation

   https://doi.org/10.2138/gselements.19.5.296  

   Macdonald, Francis A; Swanson-Hysell, Nicholas L (October 2023, Elements)

   Large igneous provinces (LIPs) can potentially cause cooling on tens- to thousand-year timescales via injection of sulfur aerosols to the tropo-sphere, and on million-year timescales due to the increase of global weatherability. The ca. 719-Ma Franklin LIP preceded onset of the Sturtian Snowball Earth glaciation by less than two million years, consistent with CO2 drawdown due to weathering of Ca- and Mg-rich LIP basalts, which may have contributed to cooling past a critical runaway ice-albedo threshold. A relatively cool background climate state and Franklin LIP emplacement near a continental margin in the warm wet tropics may have been critical factors for pushing the Earth’s climate past the threshold of runaway glaciation. 

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3. Lip service: Histological phenotypes correlate with diet and feeding ecology in herbivorous pacus

   https://doi.org/10.1002/ar.25075  

   Cohen, Karly E.; Lucanus, Oliver; Summers, Adam P.; Kolmann, Matthew A. (October 2022, The Anatomical Record)

   Abstract Complex prey processing requires the repositioning of food between the teeth, as modulated by a soft tissue appendage like a tongue or lips. In this study, we trace the evolution of lips and ligaments, which are used during prey capture and prey processing in an herbivorous group of fishes. Pacus (Serrasalmidae) are Neotropical freshwater fishes that feed on leaves, fruits, and seeds. These prey are hard or tough, require high forces to fracture, contain abrasive or caustic elements, or deform considerably before failure. Pacus are gape‐limited and do not have the pharyngeal jaws many bony fishes use to dismantle and/or transport prey. Despite their gape limitation, pacus feed on prey larger than their mouths, relying on robust teeth and a hypertrophied lower lip for manipulation and breakdown of food. We used histology to compare the lip morphology across 14 species of pacus and piranhas to better understand this soft tissue. We found that frugivorous pacus have larger, more complex lips which are innervated and folded at their surface, while grazing species have callused, mucus‐covered lips. Unlike mammalian lips or tongues, pacu lips lack any intrinsic skeletal or smooth muscle. This implies that pacu lips lack dexterity; however, we found a novel connection to the primordial ligament which suggests that the lips are actuated by the jaw adductors. We propose that pacus combine hydraulic repositioning of prey inside the buccal cavity with direct oral manipulation, the latter using a combination of a morphologically heterodont dentition and compliant lips for reorienting food. 

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4. Continental flood basalts drive Phanerozoic extinctions

   https://doi.org/10.1073/pnas.2120441119  

   Green, Theodore; Renne, Paul R.; Keller, C. Brenhin (September 2022, Proceedings of the National Academy of Sciences)

   Refinements of the geological timescale driven by the increasing precision and accuracy of radiometric dating have revealed an apparent correlation between large igneous provinces (LIPs) and intervals of Phanerozoic faunal turnover that has been much discussed at a qualitative level. However, the extent to which such correlations are likely to occur by chance has yet to be quantitatively tested, and other kill mechanisms have been suggested for many mass extinctions. Here, we show that the degree of temporal correlation between continental LIPs and faunal turnover in the Phanerozoic is unlikely to occur by chance, suggesting a causal relationship linking extinctions and continental flood basalts. The relationship is stronger for LIPs with higher estimated eruptive rates and for stage boundaries with higher extinction magnitudes. This suggests LIP magma degassing as a primary kill mechanism for mass extinctions and other intervals of faunal turnover, which may be related to CO 2 ,   SO 2 , Cl, and F release. Our results suggest continental LIPs as a major, direct driver of extinctions throughout the Phanerozoic. 

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5. A red bole zircon record of cryptic silicic volcanism in the Deccan Traps, India

   https://doi.org/10.1130/G49613.1  

   O’Connor, Liam; Szymanowski, Dawid; Eddy, Michael P.; Samperton, Kyle M.; Schoene, Blair (January 2022, Geology)

   Abstract Silicic magmas within large igneous provinces (LIPs) are understudied relative to volumetrically dominant mafic magmas despite their prevalence and possible contribution to LIP-induced environmental degradation. In the 66 Ma Deccan LIP (India), evolved magmatism is documented, but its geographic distribution, duration, and significance remain poorly understood. Zircons deposited in weathered Deccan lava flow tops (“red boles”) offer a means of indirectly studying potentially widespread, silicic, explosive volcanism spanning the entire period of flood basalt eruptions. We explored this record through analysis of trace elements and Hf isotopes in zircon crystals previously dated by U–Pb geochronology. Our results show that zircon populations within individual red boles fingerprint distinct volcanic sources that likely developed in an intraplate setting on cratonic Indian lithosphere. However, our red bole zircon geochemical and isotopic characteristics do not match those from previously studied silicic magmatic centers, indicating that they must derive from yet undiscovered or understudied volcanic centers associated with the Deccan LIP. 

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