A hidden alkaline and carbonatite province of early carboniferous age in northeast Poland: Zircon U-Pb and pyrrhotite Re-Os geochronology

Extensive geophysical investigations in NE Poland in the 1950s and 1960s led to the discovery of an alkaline and carbonatite magmatic province buried under thick (600-800 m) Meso-Cenozoic cover north of the Trans-European Suture Zone, or Tornquist Line. Drilling focused on geophysical anomalies identified three intrusions in the Paleoproterozoic metasedimentary and metavolcanic rocks of the Mazowsze Domain: the Pisz gabbro-syenite massif, the Ełk syenite massif, and the small, differentiated Tajno body consisting of clinopyroxenite cumulates and syenites crosscut by carbonatite veins. Emplacement ages for these intrusions have been obtained by (1) zircon U-Pb geochronology on a gabbro from Pisz, a syenite from Ełk, and an albitite from Tajno and (2) a Re-Os model age for pyrrhotite from a Tajno carbonatite. The ages measured by both methods fall in the narrow range 354-345 Ma (Early Carboniferous: Tournaisian). This is slightly younger than the Late Devonian (380-360 Ma) Kola Peninsula alkaline and carbonatite province (20 intrusions) of NW Russia and Karelia but is of comparable age to the first manifestations of the long-lasting (~100 m.yr.) Carboniferous to Permian magmatic event (360-250 Ma) manifest in northern Europe (from the British Isles to southern Scandinavia, the North Sea, and northern Germany) in the foreland of the Variscan orogeny (in the so-called West European Carboniferous Basin) and the East European Craton

Contribution to the Mineral Chemistry of the Proterozoic Aravalli Mafic Meta-Volcanic Rocks from Rajasthan, NW India

Field, petrological and mineral chemistry for meta-volcanic rocks from the Aravalli sequence (Aravalli Craton, India) are presented. Field evidence such as volcanic flows and suspect pillow lava structures, dominant Fe-tholeiite lava flows intercalated with quartzites and argillaceous sediments, indicate rift tectonic environment. Primary mineralogy was obliterated during post-magmatic processes such as metamorphism corresponding to the greenschist to lower amphibolite facies conditions. The rock’s mineral composition was overprinted by plagioclase–chlorite–amphibole–epidote assemblage. The relicts of clinopyroxene were observed. The P-T estimation indicates a temperature of 550–600 °C for the pressure ranging from 3.0 to 7.0 kbar for the majority of amphiboles and 8.0–10.7 kbar for the minority. Geochemically, these rocks are komatiitic (picritic) and high-Fe tholeiitic basalts with 45.06−59.2 wt.% SiO2 and MgO content from 5 to 22.4 wt.% and Mg# of 17 to 71. They show large-ion lithophile elements (LILE) and light rare-earth elements (LREE) enrichment. Chondrite normalized rare-earth elements (REE) patterns for the Aravalli lava are moderately enriched with (La/Sm)N = 1.1−3.85, (La/Yb)N from 1.49 (komatiites) to 14.91 (komatiitic basalts). The trace element systematics with the negative Nb, P and Zr anomalies reflect their derivation from enriched sub-continental lithospheric sources, although minor crustal contamination cannot be ruled out. Aravalli rocks are considered to represent the transition from continental rift magmatism to shallow submarine eruption

Comparative geochemical assessment of jotunite rocks from the Suwałki Massif and the Sejny Intrusion (NE Poland)

Jotunites (hypersthene monzodiorites/ferromonzodiorites) are rocks coeval with plutonic AMCG (anorthosite– mangerite–charnockite–rapakivi granite) suites, which are characteristic of the Proterozoic Eon. It has been experimentally shown that jotunite magma can be recognised as parental to anorthosites and related rocks: since then, research on these rocks has taken on a particular importance. Jotunites were recently described within the deeply buried c. 1.5 Ga Suwałki and Sejny anorthosite massifs in the crystalline basement of NE Poland. The major and trace element compositions of Polish jotunites show them to have a calc-alkalic to alkali-calcic and ferroan character, with a relatively wide range of SiO2 content (40.56 wt. % up to 47.46 wt. %) and high concentrations of Fe (up to 22.63 wt. % Fe2O3), Ti (up to 4.34 wt. % TiO2) and P (up to 1.46 wt. % P2O5). Slight differences in textural features, mineralogical compositions, and geochemistry of whole-rock jotunite samples from distinct massifs allow us to distinguish two kinds: a primitive one, present in the Sejny Intrusion, and a more evolved one, related to the Suwałki Massif

Deterioration of stone buildings : mainfactors and processes

The condition of stone building objects is determined by many physicochemical factors and destructive processes. All stone materials are subject to natural aging, losing many of their primordial properties. The destructive processes and decline of the stone quality are termed the "deterioration ” (Latin: deterior - worse). This definition is close to that of rock weathering. However, weathering and deterioration are two different concepts. Weathering is a large-scale process related to large rock masses located in a geological environment. By contrast, deterioration refers to processes destroying a stone material, which has already been treated with stonework. The most known field of research for the deterioration processes are all historical old monuments. It is assumed that the deterioration reaches such a depth as those influenced by changes that take place on the stone object surface during the adsorption of solar radiation and deep penetration of oxygen and carbonated water, coming from infiltration of atmospheric precipitation or surface water. The most prominent factors of deterioration are caused by temperature changes, crystallization pressure of salts dissolved in water, gaseous pollutants and dust contained in the air, wind, hail and snow action, adsorption of acidic chemical substances, and dust particles, activity of microorganisms, fungi and lichens living on surfaces of monuments

Internal structure of the buried Suwałki Anorthosite Massif (East European Craton, NE Poland) based on borehole, magnetic and gravity data combined with new petrological results

Advanced magnetic and gravity data analysis has been used to acquire geophysical constraints providing new insights into the geological structure of the Suwałki Anorthosite Massif (SAM). The large negative magnetic anomaly of the SAM anorthosite intrusion is a result of the negative inclination of remanent magnetization, directed antiparallel to the present Earth’s magnetic field. Several filtering processes were applied to the magnetic and gravity maps to better understand the subsurface geology of the SAM area. The geological analysis of residual magnetic and gravity anomaly maps reveals the presence of different rock units, reflecting variation in petrological composition of the crystalline basement rocks. The 2-D modelling of magnetic and gravity data delineate the location and extent of the anorthosite-norite massif. The data is consistent with a thick upper crustal body with density 2690 kg/m3, low susceptibility (0.005 SI) and natural remanent magnetization (1.95 A/m), having inclination of I = –68°, and declination of D = –177°. The rocks bordering the central anorthosite body consist of norite and gabbronorite, granodiorite, diorite and charnockite. These main crystalline basement crustal units are shown more precisely on a new geological map of the SAM

A Late Paleoproterozoic (1.80 Ga) subduction-related mafic igneous suite from Lomza, NE Poland

The Lomza orthoamphibolites in the crystalline basement of NE Poland, dated at 1802 ± 9 Ma by SHRIMP zircon U-Pb, are characterized by high incompatible and REE element contents. These features, the low Nb, and the position of the rock compositions on L

Geochronologia detrytycznego cyrkonu i proweniencja proterozoicznych bogatych w kwarc skał metaosadowych w domenie mazowieckiej: obszary źródłowe i regionalna korelacja

Drilling at Mońki IG 2 and Zabiele IG 1 in the Mazowsze domain has intersected mature quartz-rich metasedimentary rocks belonging to the basement of NE Poland, described so far as a Biebrza complex. The geochemical composition of these rocks is charac¬teristic of a passive margin. The subarkose–quartz arenite underwent low-T metamorphism, but preserved textures typical for the fluvial sediments. The detrital material in range 1.68–2.11 Ga was provided from surrounding late Paleoproterozoic margins of the Fennoscandia and Sarmatia. The maximum depositional age probably did not exceed 1.6 Ga. A previously suggested correlation with Mesoproterozoic molasse-type deposits of the Jotnian formation has not been confirmed. It seems more likely that the sediments formed after Fennoscandia-Sarmatia collision (i.e. termination of Svecofennian orogeny) but before denudation of the Mesoproterozoic Mazury AMCG intrusions.W otworach wiertniczych Mońki IG 2 i Zabiele IG 1 na obszarze domeny mazowieckiej rozpoznano dojrzałe, bogate w kwarc skały metaosadowe. Należą one do podłoża krystalicznego północno-wschodniej Polski i były opisywane dotychczas jako kompleks biebrzański. Skład geochemiczny tych skał jest charakterystyczny dla krawędzi pasywnej. Skały sklasyfikowane jako arenity kwarcowe i subarkozy uległy metamorfizmowi niskotemperaturowemu, zachowując jednak struktury typowe dla osadów rzecznych. Materiał detrytyczny o wieku 1,68–2,11 mld lat pochodził z erozji paleoproterozoicznych skał na krawędziach Fennoskandii i Sarmacji. Maksymalny wiek depozycji materiału okruchowego prawdopodobnie nie przekraczał 1,6 mld lat. Sugerowana wcześniej korelacja z osadami molasowymi mezoproterozoicznej formacji jotnickiej nie została potwierdzona. Bardziej prawdopodobne wydaje się, że osady powstały po kolizji Fennoskandii z Sarmacją (wygasanie orogenezy swekofeńskiej), a przed denudacją mezoproterozoicznych intruzji AMCG obszaru Mazur

New reports from the Earth inside

A new research has been done on the high pressure minerals from the Earth’s Mantle Transition and Lower Zone. The Earth’s Mantle extends from the “Moho” (Mohoroviè) discontinuity down to a depth of 2,900 km and constitutes 83% of the Earth’s volume and 67% of its mass.The mantle is further divided into two seismic regions: the upper and thelower mantle separated by a seismic zone of discontinuity at a depth of 670 km, which is also the maximum depth to which subducted lithospheric plates can reach. The additional discontinuity zone, i.e. a depth of 410 km together with a zone of 670 km, corresponds to the transformation site of the silicate mineral structure, which also affects the speed of propagation of seismic waves. Mantle peridotite samples indicate that olivine is the main component of the uppermost part of the upper mantle, up to adepth of 410 km. At greater depths, down to 660 km, in the so-called Transition, transformation of olivine into its high-pressure poly-morphs (wadsleyite and ringwoodite) showing a spinel structure, is observed. Experimental research data on natural bridgmanite((Mg, Fe)SiO3), which exhibits a perovskite structure and is the main mineral of the lower mantle and the most common mineral in the Earth, have been presented. The problem of nitrogen and water amounts in the Earth’s lower mantle and a content of new iron polymorphs in the Earth’s core have also been discussed