Francesco Sauro

Microbial mediation of complex subterranean mineral structures

Helictites—an enigmatic type of mineral structure occurring in some caves—differ from classical speleothems as they develop with orientations that defy gravity. While theories for helictite formation have been forwarded, their genesis remains equivocal. Here, we show that a remarkable suite of helictites occurring in Asperge Cave (France) are formed by biologically-mediated processes, rather than abiotic processes as had hitherto been proposed. Morphological and petro-physical properties are inconsistent with mineral precipitation under purely physico-chemical control. Instead, microanalysis and molecular-biological investigation reveals the presence of a prokaryotic biofilm intimately associated with the mineral structures. We propose that microbially-influenced mineralization proceeds within a gliding biofilm which serves as a nucleation site for CaCO3, and where chemotaxis influences the trajectory of mineral growth, determining the macroscopic morphology of the speleothems. The influence of biofilms may explain the occurrence of similar speleothems in other caves worldwide, and sheds light on novel biomineralization processes.

Rossiantonite, Al3(PO4)(SO4)2(OH)2(H2O)10•4H2O, a new hydrated aluminum phosphate-sulfate mineral from Chimanta massif, Venezuela: Description and crystal structure

Abstract Rossiantonite, ideally Al3(PO4)(SO4)2(OH)2(H2O)10·4H2O, triclinic (space group P1̄), a = 10.3410(5), b = 10.9600(5), c = 11.1446(5) Å, a = 86.985(2), b = 65.727(2), g = 75.064(2)°, V = 1110.5(1) Å3, Z = 2, is a new mineral from the Akopan-Dal Cin cave system in the Chimanta massif (Guyana Shield, Venezuela). The mineral occurs as small (≤0.15 mm) and transparent crystals in a white to slightly pink fine-grained sand, filling spaces between boulders of weathered quartz sandstone. Associated phases are gypsum, sanjuanite, rare alunite, quartz and micro-spherules of amorphous silica. Rossiantonite is colorless with a white streak and vitreous luster. The mineral is brittle with irregular to sub-conchoidal fracture and it shows a poorly developed cleavage. Rossiantonite is biaxial and not pleochroic, with mean refractive index of 1.504. The calculated density is 1.958 g/cm3. Electron microprobe analyses, with H2O measured by thermogravimetric analysis, provided the following empirical formula based on 28 O apfu: Al2.96Fe0.03P1.01S2H30.02O28. The five strongest lines in the X‑ray powder diffraction pattern, expressed as d (Å), I, (hkl) are: 4.647, 100, (210); 9.12, 56, (100); 4.006, 53, (220); 8.02, 40, (110); 7.12, 33, (011). The crystal structure, refined using 3550 unique reflections to R = 0.0292, is built of PO4 and AlO6 polyhedral rings, creating complex chains parallel b by sharing the OH-OH edge belonging to the Al(3) polyhedron. Three symmetrically independent Al sites can be identified, namely: Al(1), Al(2), and Al(3). Tetrahedral sites, occupied by P, share all their apexes with AlO6 octahedra. Unshared octahedral apexes are occupied by water molecules. Four additional water molecules are placed in between the previously identified chains. Two oxygen tetrahedra, occupied by S atoms, are connected along the chains by means of weak hydrogen bonding. The rossiantonite structure shows similarities with minerals belonging to the sanjuanite-destinezite group.

Evaporite karst in Italy: a review

*jo.dewaele@unibo.it Citation:

Secondary minerals from salt caves in the Atacama Desert (Chile): a hyperarid and hypersaline environment with potential analogies to the Martian subsurface

*jo.dewaele@unibo.it Citation:

IMA Commission on New Minerals, Nomenclature and Classification (CNMNC)

The information given here is provided by the IMA Commission on New Minerals, Nomenclature and Classification for comparative purposes and as a service to mineralogists working on new species. Each mineral is described in the following format: Mineral name, if the authors agree on its release prior to the full description appearing in press Chemical formula Type locality Full authorship of proposal E-mail address of corresponding author Relationship to other minerals Crystal system, Space group; Structure determined, yes or no Unit-cell parameters Strongest lines in the X-ray powder diffraction pattern Type specimen repository and specimen number Citation details for the mineral prior to publication of full description Citation details concern the fact that this information will be published in the Mineralogical Magazine on a routine basis, as well as being added month by month to the Commissions web site. It is still a requirement for the authors to publish a full description of the new mineral. NO OTHER INFORMATION WILL BE RELEASED BY THE COMMISSION IMA No. 2012-039 Ca1–2Fe[(Si,Al,Be)5Be2O13(OH)2]·2H2O In a syenite pegmatite at Langangen, Blafjell, Norway (59°5′34″N 9°41′38″E) and the A/S Granite Quarry, Tvedalen, Vestfold, Norway J. Grice*, R. Kristiansen, H. Friis, R. Rowe, R.S. Selbekk, M. Cooper, A.O. Larsen and G. Poirier *E-mail: jgrice@mus-nature.ca Interrupted framework zeolite Monoclinic: P 21/ c ; structure determined a = 8.759(5), b = 4.864(2), c = 31.258(7) A, β = 90.31(3)° 15.555(100), 4.104(29), 3.938(36), 3.909(60), 3.820(30), 3.251(66), 3.186(27), 2.884(64) Type material is deposited in the collections of the Canadian Museum of Nature, Ottawa, Canada, specimen number CNMMC 86554, and the Natural History Museum, Oslo, Norway, specimen numbers 43434 and 43435 How to cite: Grice, J., Kristiansen, R., Friis, H., Rowe, R., Selbekk, R.S., Cooper, M., Larsen, A.O. and …

Subsurface scientific exploration of extraterrestrial environments (MINAR 5): analogue science, technology and education in the Boulby Mine, UK

The deep subsurface of other planetary bodies is of special interest for robotic and human exploration. The subsurface provides access to planetary interior processes, thus yielding insights into planetary formation and evolution. On Mars, the subsurface might harbour the most habitable conditions. In the context of human exploration, the subsurface can provide refugia for habitation from extreme surface conditions. We describe the fifth Mine Analogue Research (MINAR 5) programme at 1 km depth in the Boulby Mine, UK in collaboration with Spaceward Bound NASA and the Kalam Centre, India, to test instruments and methods for the robotic and human exploration of deep environments on the Moon and Mars. The geological context in Permian evaporites provides an analogue to evaporitic materials on other planetary bodies such as Mars. A wide range of sample acquisition instruments (NASA drills, Small Planetary Impulse Tool (SPLIT) robotic hammer, universal sampling bags), analytical instruments (Raman spectroscopy, Close-Up Imager, Minion DNA sequencing technology, methane stable isotope analysis, biomolecule and metabolic life detection instruments) and environmental monitoring equipment (passive air particle sampler, particle detectors and environmental monitoring equipment) was deployed in an integrated campaign. Investigations included studying the geochemical signatures of chloride and sulphate evaporitic minerals, testing methods for life detection and planetary protection around human-tended operations, and investigations on the radiation environment of the deep subsurface. The MINAR analogue activity occurs in an active mine, showing how the development of space exploration technology can be used to contribute to addressing immediate Earth-based challenges. During the campaign, in collaboration with European Space Agency (ESA), MINAR was used for astronaut familiarization with future exploration tools and techniques. The campaign was used to develop primary and secondary school and primary to secondary transition curriculum materials on-site during the campaign which was focused on a classroom extra vehicular activity simulation.