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Abstract: Several levels of the Lorraine Group (Upper Ordovician) in upstate New York (USA) have yielded low-diversity, exceptionally preserved, pyritized invertebrate assemblages dominated by the trilobite Triarthrus eatoni. Sedimentological and taphonomic features suggest dysoxic bottom-water conditions, with limited transport and rapid burial by distal turbidites. Echinoderms are extremely rare in these strata. Here we report, for the first time, the occurrence of the anomalocystitid mitrate Enoploura popei in the Konservat-Lagerstätte of Beecher's Trilobite Bed. A pyritized specimen of this stylophoran was CT-scanned and three-dimensionally reconstructed. The mitrate is laterally compressed, but its 3D-rendering provided several insights into its internal anatomy and taphonomy. The recurved position of the single feeding appendage (aulacophore) is consistent with ligament-induced, post mortem contraction. This posture and the collapse of one lateral series of cover plates indicate that the individual was probably not buried alive. Nevertheless, a portion of the distal aulacophore shows clear evidence of exceptionally preserved soft parts (ambulacral system) in between two sets of slightly open cover plates and the underlying ossicles. One of the most intriguing features of this specimen is its close association with a sinuous, elongated, pyritized trace fossil, which enters the stylophoran through the mouth and disappears into the proximal aulacophore. In marked contrast with other skeletal parts of the specimen (theca and distal part of the aulacophore), the proximal rings of the aulacophore are heavily disrupted and disarticulated. Proximal rings are usually decay-resistant skeletal regions in stylophorans. Therefore, close association of this disrupted region with a trace fossil penetrating it suggests the action of an unknown infaunal scavenger. Location of this trace suggests targeting during early decay of the large muscular proximal aulacophore. 

Abstract Recharges of magma underneath basaltic volcanoes can occur as precursory events prior to an eruption but are not always revealed in geophysical data streams or erupted lavas compositions. In contrast, phosphorus within primitive, Mg‐rich (Fo_89‐90), olivine can preserve recharge information lost by the mixed melt. Evidence of rapid growth and dissolution are preserved only in phosphorus X‐ray intensity maps, which reveal that Mg‐rich olivine from eruptions occurring between 2008 and 2020 at Kīlauea Volcano (Hawaiʻi) experienced at least two episodes of magma intrusion. We develop numerical diffusion models that evaluate the fidelity of the Fe‐Mg compositional archive by quantifying three factors that influence Fo population distributions: (a) the frequency at which an Mg‐rich basaltic liquid (in equilibrium with Fo₉₀olivine) intrudes the reservoir, (b) the pre‐existence of a polymodal distribution of olivine crystal sizes and their shapes (c) the effects of sectioning on apparent olivine core compositions. We find that most crystals lose their initial Mg‐rich composition if they are held at temperatures relevant to summit magma storage conditions (1,160–1,190°C) for more than 10 years. Thus, previous assertions that Mg‐rich olivine crystals at Kīlauea are scavenged from centuries‐old stored magmas are unrealistic. Our method permits critical evaluation of contrasting explanations of heterogeneous Fe‐Mg contents of olivine cargo: (a) different total durations of mush storage with partial diffusive erasure of compositional traits, or (b) coexistence of multiple chemically distinct magmas. Our approach provides general guidance for the conservative interpretation of temporal information preserved within olivine Fe‐Mg compositional archives. 

We have studied optical properties of single and multi-fold nanoporous gold leaf metamaterials and demonstrated that they can be controlled with applied voltage and dielectric environment.