Depth of Formation of Ferropericlase Included in Super-Deep Diamonds

Super-deep diamonds are believed to have formed at depths of at least 300 km depth (Harte, 2010). A common mineral inclusion in these diamonds is ferropericlase, (Mg,Fe)O (see Kaminsky, 2012 and references therein). Ferropericlase (fPer) is the second most abundant mineral in the lower mantle, comprising approximately 16\u201320 wt% (660 to 2900 km depth), and inclusions of fPer in diamond are often considered to indicate a lower-mantle origin (Harte et al., 1999). Samples from S\ue3o Luiz/Juina, Brazil, are noteworthy for containing nanometer-sized magnesioferrite (Harte et al., 1999; Wirth et al., 2014; Kaminsky et al., 2015; Palot et al., 2016). Based upon a phase diagram valid for 1 atm, such exsolutions would place the origin of this assemblage in the uppermost part of the lower mantle. However, a newly reported phase diagram for magnesioferrite demonstrates that the latter is not stable at such pressures and, thus, it cannot exsolve directly from fPer at lower-mantle conditions (Uenver-Thiele et al., 2017). Here we report the investigation of two fPer inclusions, extracted from a single S\ue3o Luiz diamond, by single-crystal X-ray diffraction and field emission scanning electron microscopy. Both techniques showed micrometer-sized exsolutions of magnesioferrite within the two fPers. We also completed elastic geobarometry (see Angel et al., 2015), which determined an estimate for the depth of entrapment of the two ferropericlase \u2013 diamond pairs. In the temperature range between 1273 and 1773 K, pressures varied between 9.88 and 12.34 GPa (325-410 km depth) for one inclusion and between 10.69 and 13.16 GPa (350-440 km depth) for the other one. These results strengthen the hypothesis that solitary fPer inclusions might not be reliable markers for a lower-mantle provenance

Investigations on the emplacement mechanisms of the Eocene olistoliths of the Miramare Castle (Trieste, Italy)

Eocene Flysch deposits are widespread in north-eastern Italy, Slovenia and Croatia and represent the sedimentation in the foreland basin of the Dinaric chain. Flysch extensively outcrops in the surroundings of Trieste at the front of the Carso Anticline. The Carso Anticline is a large NW/SE trending structure in the thick carbonate succession of the Friuli Carbonate Platform, a shallow water carbonate domain representing the northeastern termination of the large Adriatic Carbonate Platform that stretched from northeastern Italy to Montenegro and hosted shallow water sedimentation for large part of the Mesozoic and the Cenozoic.A rather unknown peculiarity of the Trieste Fysch succession is that at Castle of Miramare, in the vicinity of Trieste, it is found in association with a series of large calcareous blocks that make up the promontory on which the castle is built. Approximately, a hundred calcareous blocks having volumes ranging from about 500,000 m3 to 1,300,000 m3, were identied in previous mapping campaigns. Tonelli (2001) highlighted that the blocks are made of Eocene platform limestone belonging to the Miliolid, Alveolinids and Nummulites Limestone. The Miliolids, Alveolinids and Nummulites Limestone represents a phase of carbonate deposition that took place when the Friuli Platform in this sector was inuenced by fore-bulging of the Dinaric chain that was advancing from the northeast. The blocks overlie and are overlain by ysch, thus testifying that their deposition was, at least in part, contemporaneous to that of the ysch itself. The presence of marly conglomerate lithofacies, in places associated to the blocks, has been interpreted as the matrix of a cohesive debris Flow of which the calcareous blocks are olistoliths. Whereas the blocks have been mapped and some of their features identied, the mechanisms of their deposition are not yet completely understood. In this contribution, we present new data concerning the characteristics of the calcareous blocks, their spatial relationships with the Flysch and the associated deformations that help shedding light on the processes that operated during the emplacement of the Miramare olistoliths. Tonelli N. (2001) - L’origine dei blocchi calcarei del parco di Miramare (Trieste). Tesi di laurea inedita. Università degli Studi di Trieste

The Mass-Transport Deposits of the Paleogene Julian Basin (Italy/Slovenia): observations on the dynamic of emplacement and tsunamigenic potential

The External Dinarides between Italy and Slovenia feature some exceptional exposures of Paleocene-Eocene Mass-Transport Deposits (MTDs) formed by repeated catastrophic events, in which large sectors of the Adriatic Carbonate Platform collapsed and redeposited in a foredeep basin system, the Julian Basin. The sedimentary succession of the basin contains at least 25 major MTDs. The largest can be up to 260 m thick and can be traced laterally for at least 100 km. The mechanism of emplacement of these “megabeds” consists of a bipartite flow of material with a cohesive blocky/debris flow at the base, and a grain to turbulent flow on top. Each MTD features basal units of calcareous breccias embedding carbonate, siliciclastic-carbonate and marly slide blocks, topped by graded calcirudite, calcarenite and marlstone deposits. Here we discuss new interpretations of some representative megabeds, exposed in the area’s main open-pit quarries, based on X-ray fluorescence spectrometry (XRF), Powder X-ray diffraction (Powder XRD) and Total Organic Carbon (TOC) data, together with outcrop analysis carried out in the field and on Virtual Outcrop Models (VOMs). Results provide new insights into the emplacement dynamics and tsunamigenic potential of the MTDs in the Julian Basin. The inferred shape of the basin, the dimensions of the main "megabeds" and the data analysis from the above outcrops suggest that some of these submarine landslides may have triggered tsunami waves, with possible subsequent rebound deposits on top of them, traces of which are possibly recorded by multiple geological-geochemical proxies

Depth of diamond formation obtained from single periclase inclusions

Super-deep diamonds (SDDs) are those that form at depths between ~300 and ~1000 km in Earth\u2019s mantle. They compose only 1% of the entire diamond population but play a pivotal role in geology, as they represent the deepest direct samples from the interior of our planet. Ferropericlase, (Mg,Fe)O, is the most abundant mineral found as inclusions in SDDs and, when associated with low-Ni enstatite, which is interpreted as retrogressed bridgmanite, is considered proof of a lower-mantle origin. As this mineral association in diamond is very rare, the depth of formation of most ferropericlase inclusions remains uncertain. Here we report geobarometric estimates based on both elasticity and elastoplasticity theories for two ferropericlase inclusions, not associated with enstatite, from a single Brazilian diamond. We obtained a minimum depth of entrapment of 15.7 (\ub12.5) GPa at 1830 (\ub145) K (~450 [\ub170] km depth), placing the origin of the diamond-inclusion pairs at least near the upper mantle\u2013transition zone boundary and confirming their super-deep origin. Our analytical approach can be applied to any type of mineral inclusion in diamond and is expected to allow better insights into the depth distribution and origin of SDDs

Subcutaneous immunoglobulins replacement therapy in secondary antibody deficiencies: Real life evidence as compared to primary antibody deficiencies

Secondary antibody deficiencies (SAD) may require immunoglobulin replacement therapy (IgRT). While the intravenous route (IVIG) is broadly considered effective in SAD, the use of subcutaneous immunoglobulins (SCIG) is mainly adopted from the experience in primary antibody deficiencies (PAD), where SCIG have been shown to perform as effective as IVIG. However, evidence-based data on SCIG administration in SAD patients are still insufficient. Herein we retrospectively evaluated the efficacy and safety profile of SCIG treatment in 131 SAD patients as compared to a group of 102 PAD patients. We found SCIG being equally effective in reducing annual infectious rate both in SAD and PAD patients. However, SAD patients required lower SCIG dosage and lower IgG through level to achieve similar biological effect in terms of infection burden, at the steady state. SAD patients also showed better correlation between SCIG dose and serum IgG achieved value. Furthermore, within SAD, SCIG were found to work irrespective of the underlying disease. Especially in Non-Hodgkin Lymphoma patients, whose indication to IgRT is still not included in all guidelines and for whom evidence-based data are still lacking, SCIG were as effective as in Chronic Lymphocytic Leukemia or Multiple Myeloma patients, and SCIG discontinuation, without evidence of B cell recovery, led to IgG decline and relapsed infections. Finally, treatment tolerance in SAD patients was comparable to the PAD cohort. Globally, our data suggest that SCIG, as already appreciated in PAD, represent a valuable option in SAD patients, independent on the disease leading to antibody deficiency