Swedish Museum of Natural History
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Värdväxten Johannesört Hypericum spp.
No full textJohannesörter Hypericum spp. är ett släkte med sju arter i Sverige. De känns igen på de gula femtaliga blommorna med många ståndare. Fem av arterna är antingen sällsynta eller väldigt lokalt förekommande. Man syftar därför främst på de två vanliga arterna äkta johannesört H. perforatum och fyrkantig johannesört H.maculatum när man pratar om demsom värdväxter för insekter. Dessatvå arter förekommer i liknande biotoper, främst på torra till medelfuktiga gräsmarker och ruderatmarker. De kan förekomma i stor mängd på igenväxningsmarker. Fyrkantig johannesört finns generellt på lite fuktigare marker och längre norrut än äkta johannesört. Johannesörthar också kallats mannablod eftersom krossade blomknoppar ger enblodröd färg
Cambrian ecological complexities: Perspectives from the earliest brachiopod – supported benthic communities in the early Cambrian Guanshan Lagerstätte
No full textThe Cambrian radiation is characterized by the emergence of diverse bilaterian animal phyla and theestablishment of complex marine ecosystems. The Guanshan Biota records an unusual ecological transition from trilobite- to brachiopod-dominated communities during Cambrian Stage 4. This community transition is accompanied by direct evidence of in situ biological interactions such as durophagous pre-dation and kleptoparasitism. Here we describe new material from the Guanshan biota, focusing on an association of palaeoscolecidomorphs and brachiopods with parasitic tube worms that occur on micro-bedding planes. The bedding plane assemblages are dominated by the organophosphatic brachiopod Neobolus wulongqingensis encrusted with kleptoparasitic tube-dwelling worms, along with infaunal palaeoscolecidans. Taphonomic and sedimentological evidence indicates that these specimens are com-monly preserved in life position, and thus the association between individuals represent potential biological interactions. This case study reveals that ecosystems during the early Cambrian exhibited a well-developed system of tiering and a complex trophic network, easily distinguished from the simple communities typical of precursor deposits in the Ediacaran. Brachiopods forming extremely dense concentrations on the sea floor are effectively acting as ecosystem engineers, not only to stabilize the soft-substrate seafloor, but also act as an alternative substrate for the oldest empirically demonstrated kleptoparasites.The in situ biological interactions preserved in the Guanshan Biota are critical for filling gaps in ourknowledge of ecosystem complexity in the Cambrian.This work was financially supported by the National Natural Science Foundation of China (NSFC Nos. 41720104002, 41890844, 41621003 to Zhang Zhifei and 4207020712, 42072003 to Timothy P. Topper), Strategic Priority Research Program of Chinese Academy of Sciences award to the Early Life Institute (grant XDB26000000), 111 Project of Ministry of Education of China (D17013), 1000 Talents Program (41720104002 to Timothy P. Topper and Luke C. Strotz) and Opening Foundation of State Key Laboratory of Continental Dynamics, Northwest University (21LCD02 to Chen Feiyang). </p
Garpenbergite, Mn6□As5+Sb5+O10(OH)2, a new mineral related to manganostibite, from the Garpenberg Zn–Pb–Ag deposit, Sweden
No full textGarpenbergite is a new mineral (IMA2020-099) from the Garpenberg Norra mine, Hedemora, Dalarna, Sweden. It occurs with carlfrancisite and minor stibarsen, paradocrasite and filipstadite in a fractured skarn matrix of granular jacobsite, alleghanyite, kutnohorite and dolomite. Crystals are short-prismatic, up to 1.5 mm in length. They have a blackish to greyish brown colour, and are lustrous semi-opaque, with brown streak. Garpenbergite is brittle, with an uneven to subconchoidal fracture. Cleavage is distinct on {010}. Hardness ≈ 5 (Mohs) and VHN100 = 650(40). Dcalc = 4.47(1) g⋅cm−3 , overall ncalc = 1.85. Maximum specular reflectance values (%) obtained are 9.2 (470 nm), 9.1 (546 nm), 9.0 (589 nm) and 8.9 (650 nm). The empirical chemical formula of garpenbergite, based on electron microprobe data, is (Mn2+3.97Mg1.48Mn3+0.26Zn0.29)Σ6.00(As0.89Fe3+0.04Mn3+0.06Si0.01)Σ1.00(Sb0.98Fe0.02)Σ1.00O10[(OH)1.99Cl0.01]Σ2.00. The five strongest Bragg peaks in the powder X-ray diffraction pattern [d, Å(I, %) (hkl)] are 3.05 (30) (002), 2.665 (100) (161), 2.616 (40) (301), 2.586 (25) (251) and 1.545 (45) (462). The orthorhombic unit-cell dimensions (in Å) are a = 8.6790(9), b = 18.9057(19) and c = 6.1066(6), with V = 1001.99(18) Å3 for Z = 4. The crystal structure was refined from single-crystal X-ray diffraction data in the space-group Ibmm to R1 = 3.7% for 957 reflections. Garpenbergite, ideally Mn6As5+Sb5+O10(OH)2, is isostructural with manganostibite, Mn7AsSbO12, but possesses a cation vacancy (□) at an octahedrally coordinated structural site; the two minerals are thus related by the exchange Mn2+ + 2O2– → □ + 2(OH)– . The presence of hydroxyl groups is supported by vibration bands at 3647 and 3622 cm−1 in the Raman spectrum of garpenbergite, and by bond-valence considerations
Old samples - new amphiboles
No full textThe scientific value of old and well-preserved collections is priceless. Samples that already have been studied and described can still give very useful information. For instance, minerals with complex solid solutions like amphiboles sometimes show new compositions that are feasible because of crystal-chemistry and charge arrangements, based on the current classification scheme by Hawthorne et al. (2012) for the amphibole supergroup. In the last four years, a fruitful collaboration between the Swedish Museum of Natural History and the Department of Earth Sciences of the University of Milan has allowed the identification of new amphibole species, recognized by CNMNC-IMA. First of all, we identified hjalmarite, [ANaB(NaMn)CMg5TSi8O22W(OH)2], which is related to richterite via the homovalent substitution [B]Ca2+ → [B]Mn2+, and is the second recognized member of the sodium–(magnesium–iron–manganese) subgroup, after ferri-ghoseite. Sjögren (1891) had described a physically similar, MnO-rich sample from Långban, named “astochit”. A related amphibole, although belonging to a different subgroup, that we have formally described is potassic-richterite, [AKB(NaCa)CMg5TSi8O22W(OH)2]. It was found in a sample from the Pajsberg iron and manganese ore mines, which was originally collected by the mineralogist Lars Johan Igelström, probably in the 1850s. The most recent amphibole we have described is ferri-taramite [ANaB(NaCa)C(Mg3Fe3+2)T(Si6Al2)O22W(OH)2], found in a skarn sample from the Jakobsberg manganese mine: it was once examined by Flink (1914), who noted the unusual character of the amphibole and described it as a “strange hornblende”
Crystal structure and composition of hiärneite, Ca2Zr4Mn3+SbTiO16, and constitution of the calzirtite group
No full textThe crystal structure of hiärneite has been refined from single-crystal X-ray diffraction data (λ = 0.71073 Å) on type material from Långban, Värmland, Sweden. The refinement converged to R1 = 0.046 based on 1073 reflections with F2 > 4σ(F2). The tetragonal unit cell, space group I41/acd, has the parameters a = 15.2344(6) Å and c = 10.0891(6) Å with Z = 8. The mineral is isostructural with calzirtite, ideally Ca2Zr5Ti2O16, with a structural topology derived from fluorite. In hiärneite, Mn3+ is ordered at a 4- to 8-fold coordinated site (with a distorted polyhedral coordination figure), without the atom splitting encountered at the corresponding Zr-dominated site of calzirtite. The end-member formula for hiärneite is established as Ca2Zr4Mn3+SbTiO16. The calzirtite group, with calzirtite, hiärneite and tazheranite (cubic ZrO2-x), has been approved by the IMA–CNMNC
End-Permian burnout: the role of Permian–Triassic wildfires in extinction, carbon cycling, and environmental change in eastern Gondwana
No full textWildfire has been implicated as a potential driver of deforestation and continental biodiversity loss during the end-Permian extinction event (EPE; ~ 252 Ma). However, it cannot be established whether wildfire activity was anomalous during the EPE without valid pre- and post-EPE baselines. Here, we assess the changes in wildfire activity in the high-latitude lowlands of eastern Gondwana by presenting new long-term, quantitative late Permian (Lopingian) to Early Triassic records of dispersed fossil charcoal and inertinite from sediments of the Sydney Basin, eastern Australia. We also document little-transported fossil charcoal occurrences in middle to late Permian (Guadalupian to Lopingian) permineralized peats of the Lambert Graben, East Antarctica, and Sydney and Bowen basins, eastern Australia, indicating that even vegetation of consistently moist high-latitude settings was prone to regular fire events. Our records show that wildfires were consistently prevalent through the Lopingian, but the EPE demonstrates a clear spike in activity. The relatively low charcoal and inertinite baseline for the Early Triassic is likely due in part to the lower vegetation density, which would have limited fire spread. We review the evidence for middle Permian to Lower Triassic charcoal in the geosphere, and the impacts of wildfires on sedimentation processes and the evolution of landscapes. Moreover, we assess the evidence of continental extinction drivers during the EPE within eastern Australia, and critically evaluate the role of wildfires as a cause and consequence of ecosystem collapse. The initial intensification of the fire regime during the EPE likely played a role in the initial loss of wetland carbon sinks, and contributed to increased greenhouse gas emissions and land and freshwater ecosystem changes. However, we conclude that elevated wildfire frequency was a short-lived phenomenon; recurrent wildfire events were unlikely to be the direct cause of the subsequent long-term absence of peat-forming wetland vegetation, and the associated ‘coal gap’ of the Early Triassic.The authors acknowledge the support of research grant EAR-1636625 from the US National Science Foundation, and the Swedish Research Council (VR) grant 2018-04527 to SM. The Australian Antarctic Division provided financial and logistical support for fieldwork in the Prince Charles Mountains during the Austral summer of 1994–1995 via Antarctic Science Advisory Council Project 509.</p
Late Permian flora of the Little River Coal Measures, northeastern Australia
No full textA small assemblage of plant macrofossils incorporating representatives of Glossopteris, Vertebraria, Dictyopteridium, Samaropsis and Schizoneura is described from the Little River Coal Measures in northeast Queensland, Australia. The assemblage is interpreted to be of Lopingian age based on taxa shared with units in the Bowen Basin to the south. The fossil assemblage represents the northernmost late Permian flora yet described from Australia but has a typical representation of Gondwanan taxa and lacks evidence of Cathaysian elements. The only evidence of an associated fossil fauna is in the form of possible oviposition scars on some Glossopteris leaves. The assemblage is associated with coal beds and is considered to reflect growth in peat-forming alluvial plain settings under a mid-latitude humid temperate climate
Microbial biosignature preservation in carbonated serpentine from the Samail Ophiolite, Oman
No full textSerpentinization is a geological process involving the interaction of water and ultramafic rock, the chemical byproducts of which can serve as an energy source for microbial communities. Although serpentinite systems are known to host active microbial life, it is unclear to what extent fossil evidence of these communities may be preserved over time. Here we report the detection of biosignatures preserved in a mineralized fracture within drill cores from the Samail Ophiolite in Oman. Two varieties of filamentous structures were identified in association with iron oxide precipitates. The first type are interpreted as likely microbial remains, while the second type are recognized as potentially microbiological dubiofossils. Additionally, laminated structures composed of carbon and nitrogen rich material were identified and interpreted as having a microbially-associated origin. Our observations affirm the potential to detect subsurface microbial communities within serpentinizing environments and highlight a unique taphonomic window to preserve evidence of rock-hosted life.We gratefully acknowledge the Oman Drilling Science Party for facilitating access and characterization of these materials. We would like to thank Timothy Hahn for assistance during NanoSIMS analysis at the ASU Center for Isotope Analysis, and Jakob Thyr for assistance during Raman analysis at the Ångström Laboratory. We also thank Bethany Ehlmann for use of her imaging spectrometer and thank her and Elena Amador for assistance with those measurements. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. 1841051, and by the NSF GROW program. MB would like to thank the NSF EAR grant 1819550 (PI: Richard Hervig). This research used logistical support, samples and data provided by the Oman Drilling Project. The Oman Drilling Project has been possible through co-mingled funds from the International Continental Scientific Drilling Project (ICDP, lead PI’s Kelemen, Matter & Teagle), the Sloan Foundation – Deep Carbon Observatory (Grant 2014-3-01, Kelemen PI), the National Science Foundation (NSF-EAR-1516300, Kelemen PI), the NASA Astrobiology Institute (NNA15BB02A, Templeton PI), the German Research Foundation (DFG, Koepke PI), the Japanese Society for the Promotion of Science (JSPS, 16H06347, Michibayashi PI, and 19H00730, Morono PI), the European Research Council (Jamtveit PI), the Swiss National Science Foundation (Früh-Green PI), the Japanese Marine Science and Technology Center (JAMSTEC), the TAMU-JR Science operator, and in-kind contributions from the Sultanate of Oman Ministry of Regional Municipalities and Water Resources, the Oman Public Authority of Mining, Sultan Qaboos University, CRNS- Univ. Montpellier II, Columbia University, and the University of Southampton.</p