Еколого-геохімічні дослідження ґрунтів в зоні впливу підприємств чорної металургії м. Маріуполя

Вивчено закономірності розподілу і форми знаходження важких металів у ґрунтах і компонентах оточуючого середовища поблизу комбінатів чорної металургії м. Маріуполь.Изучены закономерности распределения и формы нахождения тяжелых металлов в почвах и компонентах окружающей среды вблизи комбинатов черной металлургии г. Мариуполь.There was done investigation of distribution and deportment form of heavy metals in soils and environmental components nearby the group of ferrous metallurgy enterprises of Mariupol

Geo(Im)pulse: An investigation into the genesis of an erratic (retro) eclogite block from Haren, Groningen, the Netherlands

In boulder clays and glacial deposit sands, exposed in the northern part of the Netherlands, erratic blocks of (ultra)high pressure (UHP)metamorphic rocks may be found that originate from the Baltic Shield (Scandinavia). The occurrence of (U)HP metamorphic rocks in Scandinaviais limited to: (1) isolated occurrences within the Scandinavian Caledonides (Western part of Scandinavia); (2) Sveconorvegian rocks from theHalland area, Southwest Sweden; and (3) Kola Peninsula (Northern Scandinavia). For this reason (U)HP rocks form excellent indicatorpebbles/rocks that may be used to trace back the source area from where the erratic blocks, found in the Netherlands, were derived. An exampleof this, an erratic (retro) eclogite block found in Haren, is investigated in the present study using naked eye, light-optical and electronmicroprobe (EMP) techniques. EMP mineral analyses were used to reconstruct the PT conditions under which the (retro) eclogite was formed(T = 756 °C/min. P = 16,2 kb). This result, in combination with the mineral chemistry of the major rock forming minerals, provides evidencethat this erratic block originates from the upper HP tectonic lens exposed in the Caledonian Seve Nappe Complex of Northern Jämtland, Sweden

Geo(Im)pulse: An investigation into the genesis of an erratic (retro) eclogite block from Haren, Groningen, the Netherlands

In boulder clays and glacial deposit sands, exposed in the northern part of the Netherlands, erratic blocks of (ultra)high pressure (UHP)metamorphic rocks may be found that originate from the Baltic Shield (Scandinavia). The occurrence of (U)HP metamorphic rocks in Scandinaviais limited to: (1) isolated occurrences within the Scandinavian Caledonides (Western part of Scandinavia); (2) Sveconorvegian rocks from theHalland area, Southwest Sweden; and (3) Kola Peninsula (Northern Scandinavia). For this reason (U)HP rocks form excellent indicatorpebbles/rocks that may be used to trace back the source area from where the erratic blocks, found in the Netherlands, were derived. An exampleof this, an erratic (retro) eclogite block found in Haren, is investigated in the present study using naked eye, light-optical and electronmicroprobe (EMP) techniques. EMP mineral analyses were used to reconstruct the PT conditions under which the (retro) eclogite was formed(T = 756 °C/min. P = 16,2 kb). This result, in combination with the mineral chemistry of the major rock forming minerals, provides evidencethat this erratic block originates from the upper HP tectonic lens exposed in the Caledonian Seve Nappe Complex of Northern Jämtland, Sweden

Fragments of deeper parts of the hanging wall mantle preserved as orogenic peridotites in the central belt of the Seve Nappe Complex, Sweden

Formation conditions of olivine microstructures are investigated in the Kittelfjäll spinel peridotite (KSP), a fragment of lithospheric mantle which occurs as an isolated body within high grade metamorphic crustal rocks of the Seve Nappe Complex (SNC), southern Västerbotten, central Sweden. The KSP is an orogenic peridotite containing a well developed penetrative compositional layering, defined by highly depleted dunite with olivine Mg# (100 × Mg/Mg + Fe) of 92.0–93.5 and harzburgite with lower Mg# (91.0–92.5). Dunite is characterized by three contrasting olivine microstructures formed in response to different tectonometamorphic events: Coarse-grained, highly strained olivine porphyroclasts (M1) up to 20 cm long are surrounded by dynamically recrystallized olivine grains (M2) defining a characteristic olivine “foam” microstructure (grain size: 200–2000 μm). An olivine “mortar” (M3) microstructure (10–50 μm) forms a penetrative fabric element only in strongly localized, cm-to-m sized shear zones that crosscut earlier structures/foliations. Olivine fabric analysis in synergy, with mineralogical and chemical analyses, reveals that the KSP body represents old, possibly Archean, sub-continental lithospheric mantle that was crustally emplaced into the Caledonian tectonic edifice from the hanging wall mantle during exhumation of the subducted Seve Nappe Complex (Jämtlandian orogeny ~ 454 Ma). Olivine porphyroclasts (M1) grew at high temperature during dominant isobaric cooling after extensive polybaric melt extraction (> 40%) and subsequent refertilization. The onset of the early Caledonian deformation is interpreted to be related to the crustal emplacement of the KSP during eduction of the SNC. This phase is characterized by the development of the olivine M2 foam microstructure, formed at 650–830 °C/1–2 GPa by dislocation creep processes producing an E-type CPO's by the operation of the [100](001) and subordinate [001](100) slip systems with operating flow stress levels around 8–48 MPa. In contrast the M3 olivine “mortar” microstructure formed at 550–600 °C/0.45–0.6 GPa and represents deformation after the subducted slab had returned to shallow crustal levels. It is proposed here that the presence of a penetrative olivine M2 “foam” microstructure can be used as an easy tool in the field to discriminate between mantle wedge (i.e. sub-continental affinity), ophiolite (i.e. sub-oceanic affinity), and/or hyper-extensional peridotite in the Scandinavian Caledonides. The latter two peridotite subtypes may have similar M2 microstructures, but exclusively restricted to the structural base of the bodies. Alternatively in basal parts of ophiolites, M3 microstructures directly overprint coarser grained proto-granular olivine microstructures

Evidence for diamond-grade ultra-high pressure metamorphism and fluid interaction in the Swartberget Fe-Ti garnet periodotite-websterite body, Western Gneiss Region, Norway

Based on mineral-chemical evidence we propose that the northernmost Scandian ultra-high pressure (UHP) metamorphic domain within the Western Gneiss Region of Norway can be extended 25 km northeastwards. A newly discovered, well preserved, fine-grained, Fe-Ti type garnet peridotite body at Svartberget, located in the Ulla Gneiss of the 'Møre og Romsdal' area north of Molde, is cut by a network of systematically orientated coarse-grained garnet-websterite and garnetite veins. Standard thermobarometric techniques based on electron microprobe analyses yield pressure (P) and temperature (T) estimates around 3.4 GPa, and 800°C for the peridotite body and 5.5 GPa, and 800°C for the websterite veins consistent with UHP conditions. In addition, polyphase solid inclusions, consisting of silicates, carbonates, sulphates and elemental carbon (including microdiamond), are randomly located in garnet and clinopyroxene of the websterite vein assemblage. Garnet-clinopyroxene mineral pairs yield a Sm-Nd cooling age of 393 ± 3 Ma for the peridotite and 381 ± 6 Ma for the vein assemblage suggesting that the Svartberget body was overprinted during the UHPM of the Scandian Orogeny. The initial ratio of the mineral isochron and Nd model ages suggest a mid-Proterozoic origin for the peridotite body. The polyphase inclusions, coupled with hig

Majoritic garnets monitor deep subduction fluid flow and mantle dynamics

The ultradeep mantle rocks of western Norway display three generations of majoritic garnet. The fi rst two derive from incompatible element\u2013depleted transition-zone mantle and exsolved pyroxene components during Archean upwelling, accretion to subcratonic lithosphere (M1 stage), and isobaric cooling until the Middle Proterozoic (M2). A subsequent Scandian (430\u2013390 Ma) subduction cycle initiated diamond crystallization (M3). Here we report a third majoritic garnet crystallized at grain boundaries and in microfractures, and stable with pyroxene , phlogopite, and spinel in the M3 assemblage. The trace element signatures of M3 minerals indicate crustal metasomatism, phlogopite being the main large ion lithophile element repository. These features imply majorite crystallization from crust-derived subduction fl uids at 200 km depth. Our fi nding fi xes the deepest occurrence of free subduction fl uid phases and indicates that garnet is a reliable monitor of deep mantle evolution and fl uid-mediated chemical recycling