Flow of simple superphosphate using two-stage decomposition of phosphorite

The methods for producing simple superphosphate by two-stage sulfuric acid decomposition of natural phosphates are analyzed. For the first stage, the process of decomposition of high-carbonate powdered phosphorite is studied depending on the rate of sulfuric acid from stoichiometry to the formation of H3PO4, its concentration and the reaction time of the starting components. For the second stage, the process of neutralization of phosphoric acid is studied, depending on the norm of phosphate rock for the formation of Ca(H2PO4)2. The drying process of superphosphate is carried out, in which granular superphosphate is obtained, and P2O5total. - 12%, P2O5free. - 4.6%, P2O5dig : P2O5total = 90%, P2O5 water : P2O5total = 79%.

Trifolium Repense L. Breeding In The Central Chernozem Region: Main Directions And Methods Of Work

Varieties and breeding samples of creeping clover Trifolium repense L. of lawn direction were studied in the nursery of competitive varietal trials. Using the methods of recurrent breeding involving local populations of creeping clover growing on chalk outcrops as initial forms, two varieties ‘Krasnoyaruzhsky’ and ‘Ilyok’ were obtained, as well as a new breeding sample PO 17/07. Varieties ‘Krasnoyaruzhsky’, ‘Ilyok’ and selection sample PO 17/7 are characterized by high seed productivity, the possibility of cultivation on soils with high carbonate content (burial of construction waste in an urban environment, reclamation of man-made-disturbed landscapes, etc.); high resistance to trampling. Seed yield over three years of tests in varieties ‘Krasnoyaruzhsky’, ‘Ilyok’ and breeding sample PO 17/7 significantly exceed the standard by an average of 24,6-26,8%; have uniform foliage at the level of 48-53%. Breeding sample PO 17/7 is planned to be submitted to the State variety testing.

Extant Earthly Microbial Mats and Microbialites as Models for Exploration of Life in Extraterrestrial Mat Worlds

As we expand the search for life beyond Earth, a water-dominated planet, we turn our eyes to other aquatic worlds. Microbial life found in Earth’s many extreme habitats are considered useful analogs to life forms we are likely to find in extraterrestrial bodies of water. Modern-day benthic microbial mats inhabiting the low-oxygen, high-sulfur submerged sinkholes of temperate Lake Huron (Michigan, USA) and microbialites inhabiting the shallow, high-carbonate waters of subtropical Laguna Bacalar (Yucatan Peninsula, Mexico) serve as potential working models for exploration of extraterrestrial life. In Lake Huron, delicate mats comprising motile filaments of purple-pigmented cyanobacteria capable of oxygenic and anoxygenic photosynthesis and pigment-free chemosynthetic sulfur-oxidizing bacteria lie atop soft, organic-rich sediments. In Laguna Bacalar, lithification by cyanobacteria forms massive carbonate reef structures along the shoreline. Herein, we document studies of these two distinct earthly microbial mat ecosystems and ponder how similar or modified methods of study (e.g., robotics) would be applicable to prospective mat worlds in other planets and their moons (e.g., subsurface Mars and under-ice oceans of Europa). Further studies of modern-day microbial mat and microbialite ecosystems can add to the knowledge of Earth’s biodiversity and guide the search for life in extraterrestrial hydrospheres.

Biostratigraphy and sequence stratigraphy of the Toarcian Ludwigskanal section (Franconian Alb, Southern Germany)

Extensive construction work at the canal cutting of the Ludwigskanal near Dörlbach, Franconian Alb, provided the opportunity to re-investigate a scientific-historical and biostratigraphically important reference section of the South-German Toarcian. The 16 m thick section, described bed by bed with respect to lithology and macrofossils, starts within the Upper Pliensbachian Amaltheenton Formation, covers the Toarcian Posidonienschiefer and Jurensismergel Formation, and ends in basal parts of the Opalinuston Formation. Carbonate contents are high in the Posidonienschiefer and successively decline within the Jurensismergel to basal parts of the Opalinuston. The high carbonate contents in the Posidonienschiefer are associated with comparatively low organic carbon contents. However, organic carbon contents normalized to the silicate fraction are similarily high if compared to other regions in Germany. Only the persistence of high organic carbon levels into middle parts of the Upper Toarcian differs from those of most regions in central Europe. Ammonite biostratigraphy indicates a thickness of >9 m for the Upper Pliensbachian, 1.15–1.20 m for the Lower Toarcian, 5.04 m for the Upper Toarcian, and >0.5 m for the Lower Aalenian. Despite the low sediment thickness, all Toarcian ammonite zones and almost all subzones are present, except for major parts of the Tenuicostatum Zone and the Fallaciosum Subzone. On the basis of discontinuities, condensed beds, and correlations with neighbouring sections in Southern Germany, a sequence stratigraphic interpretation is proposed for the Toarcian of this region: (i) The Posidonienschiefer Formation corresponds to one 3rd order T-R sequence, from the top of the Hawskerense Subzone to a fucoid bed at the top of the Variabilis Subzone, with a maximum flooding surface at the top of the Falciferum Zone. (ii) The Jurensismergel Formation exhibits two 3rd order T-R sequences: The first ranges from the basis of the Illustris Subzone (i.e., the Intra-Variabilis-Discontinuity) to the top of the Thouarsense Zone, with a maximum flooding surface within the Thouarsense Zone. The “belemnite battlefield” reflects a transgressive “ravinement surface” within the first Jurensismergel Sequence, not a maximum regression surface at its basis. The second sequence extents from the erosive basis of the Dispansum Zone to the top of the Aalensis Subzone, with a maximum flooding surface at the Pseudoradiosa-Aalensis Zone boundary. Finally, the Opalinuston starts with a new sequence at the basis of the Torulosum Subzone. Transgressive system tracts of these 3rd order T-R sequences are commonly phosphoritic, while some regressive system tracts show pyrite preservation of ammonites. The maximum regression surfaces at the basis of the Toarcian and within the Variabilis Zone reflect a significant submarine erosion and relief formation by seawater currents, while this effect is less pronounced at the basis of the Dispansum Zone and basis of the Torulosum Subzone (i.e., the boundary Jurensismergel-Opalinuston Formation).

Mid-Cretaceous thick carbonate accumulation in Northern Lhasa (Tibet): eustatic vs. tectonic control?

Widespread accumulation of thick carbonates is not typical of orogenic settings. During the mid-Cretaceous, near the Bangong suture in the northern Lhasa terrane, the shallow-marine carbonates of the Langshan Formation, reaching a thickness up to ∼1 km, accumulated in an epicontinental seaway over a modern area of 132 × 103 km2, about half of the Arabian/Persian Gulf. The origin of basin-wide carbonate deposits located close to a newly formed orogenic belt is not well understood, partly because of the scarcity of paleogeographic studies on the evolution of the northern Lhasa. Based on a detailed sedimentological and stratigraphic investigation, three stages in the mid-Cretaceous paleogeographic evolution of northern Lhasa were defined: (1) remnant clastic sea with deposition of Duoni/Duba formations (Early to early Late Aptian, ca. 125−116 Ma); (2) expanding carbonate seaway of Langshan Formation (latest Aptian−earliest Cenomanian, ca. 116−99 Ma); and (3) closure of the carbonate seaway represented by the Daxiong/Jingzhushan formations (Early Cenomanian to Turonian, ca. 99−92 Ma). Combined with data on tectonic subsidence and eustatic curves, we emphasized the largely eustatic control on the paleogeographic evolution of the northern Lhasa during the latest Aptian−earliest Cenomanian when the Langshan carbonates accumulated, modulated by long-term slow tectonic subsidence and high carbonate productivity.

Formation of high-transmisivity zones in the facies transition in the Bohemian Cretaceous Basin (Czech Republic)

<p>The Bohemian Cretaceous Basin (BCB) is the most important hydrogeological structure in the Czech Republic, with large sources of groundwater. The origin of high-transmissivity zones is poorly understood in many BCB areas. The doyen of Czech hydrogeology prof. Hynie described some of the largest springs to be of karst origin and he attributed the most permeable areas to facies transition between shallow-water sandstones and deep-water marlstones. In many BCB areas with large springs we can find thin sandstones and siltstones layers with high carbonate content even in stratigraphical levels corresponding with aquifers.</p><p>Research is focused on Vysoké Mýto and Ustí synclines in BCB, 125 km east of Prague in the Czech Republic. Overall 167 rock samples were taken from borehole cores and rock outcrops in this area, the most from Jizera and Bílá Hora formations. Cores were taken from intervals where: (i) high carbonate content was expected, (ii) conduits and enlarged fractures were observed at outcrops and in wells, (iii) inflows to boreholes were determined by well logging. Calcium carbonate content was determined by calcimetry in cores. Cores were leached in 10 % hydrochloric acid to observe the degree of subsequent disintegration. Polished sections were prepared from selected cores and Ca, Si, Na, K, Al content was automatically mapped by SEM-EDS to visualize the calcium, silica, feldspar and clay mineral distribution in cores.</p><p>Leaching in hydrochloric acid is an accelerated simulation of natural processes of dissolution by acidic solutions (Kůrková et al. 2019). In many aquifers in BCB there are thin calcite-rich layers with quartz sand which disintegrates after leaching calcite. Leaching of the samples in acid results in the decrease of sample strength, sometimes to their disintegration. Leaching experiments showed that the carbonate content is not the only controlling factor in the karstification process.</p><p>In sediments with detrital quartz admixture in central or western parts of the BCB the total disintegration mostly occurs between 35-50% CaCO<sub>3</sub> content depending on insoluble material content (Kůrková et al. 2020). In contrast, in the eastern part of the BCB, a degree of disintegration above 10% is documented in only 7% of the studied samples. In sediments with diagenetically precipitated cement from marine sponges even calcite content as high as 80% may not be sufficient for material to disintegrate after leaching. Disintegration occurs mainly along fractured zones where rock is heavily fractured.  </p><p>It seems that the increased content of microcrystalline silica cementy in sandy limestones and calcareous sandstones (spongolites) of the studied area has a fundamental influence on the higher cohesion and resistance of rocks to dissolution. Cause for increased cohesion is the specific spatial distribution of  microcrystalline silica, which bound the quartz grains together or formed a foam-like supporting structure in fine calcite-rich deposits.</p><p> </p><p>The research was financially supported by the GA ČR 19-14082S.</p><p> </p><p>References:</p><p>Kůrková I., Bruthans J., Balák F., Slavík M., Schweigstillová J., Bruthansová J., Mikuš P., Grundloch J. (2019): Factors controlling evolution of karst conduits in sandy limestone and calcareous sandstone (Turnov area, Czech Republic). Journal of Hydrology: 574: 1062-1073.</p>

Utilization process research of the soap industry acid waste water with high carbonate phosphorite of central Kyzylkum

In the study, the process neutralization acid waster water from soapstock processing by high calcareous phosphorite of Central Kyzylkum at temperature 60 ºC by drainless technology was investigated. As a result, digested forms of P2O5 by citric acid and Trilon B in final products were ranged 30.28-50.43 and 25.58-39.93%, respectively. Those types of products can be used under autumn chill.

Geochemical and mineralogical characterization of coastal sediments in Al-Hoceima Bay (Central Rif, Morocco)

This work aims to characterize the morphosedimentaty dynamics of the shores of Al-Hoceima Bay through geochemical and mineralogical analysis of surface sediments. The results reveal a direct relationship between marine hydrodynamic forcing on the one hand and detrital inputs from land on the other. Calcimetric analysis makes it possible to highlight the transport and deposition processes at the beaches of Al-Hoceima bay. The difference in the reasonably high carbonate contents in the western beaches (Isli, Cala Bonita and Quemado) (> 60%) and low in the beaches of the central and eastern zone (Sfiha, Souani, Salina and Lharch) (≈ 15%) are mainly due to the influence of coastal currents, littoral drift, and fluvial action. The higher levels of heavy minerals in Lharch beach (18%) are expressed by volcanic outcrops of Cap Quelates and Jbel Tamsamen. The low values at the Souani and Tayth beaches (7% on average) are due to erosion by the two types of coastal drift, NW-SE and NNE-SSW, which carry the sediments of schist origin brought by the Oueds Ghiss and Nekôr. In contrast, the reasonably high contents in the Sfiha beach (12%) are attributed to the accumulation of allochthonous sediments by NW-SE littoral drift which carries sediments of volcanometamorphic origin from Rass Quelates.

Material composition of the kursov’s assise of the vendian period of the Mirnin outshot of the Nepsk-Botuobinsk anteclise according to the results of the core material study

In this work, the object studied is the terrigenous and carbonate rocks of the Kursov’s assise of the Nepsk horizon of the Botuobinsk facies zone of the Mirnin outshot of the north-eastern part of the Nepsk-Botuobinsk anteclise. In recent years, in the course of active geological exploration work in the region, high quality core material appeared. This material was studied at the macro and micro levels, which made it possible to obtain new data on the material composition. Based on the detailed lithological description and petrographic core study, for the first time, the author gives a description and justification of the division of the Kursov’s assise into three lithological packs: low clay sand, middle carbonate clay and high carbonate clay sand. The lithological properties of the studied section reflect the characteristics of the Vendian deposition of sediments in the south of the Siberian paleocontinent. The accumulation of sandstones of the Kursov’s assise was facilitated by the weathering of magmatic rock of acidic and medium composition; the destruction products that came from the north-western part to the south-eastern part of the NepskBotuobinsk anteclise in the modern plan. In the upper-section of the Kursov’s assise, the gradual increase in the maturity of terrigenous rocks, which is associated with the duration of their transportation and repeated redeposition, is observed. The carbonate microbial formations of the middle pack of the Kursov’s assise are the first witnesses to life in the Vendian paleobasin. Their characteristic feature is the magnesia impurity.