The Mechanical Consequences of the Interplay of Mineral Distribution and Organic Matrix Orientation in the Claws of the Sea Slater Ligia pallasii

Exposed regions of the arthropod exoskeleton have specialized structure and mineral composition. Their study can provide insights into the evolutionary optimization of the cuticle as a material. We determined the structural and compositional features of claws in the crustacean Ligia pallasii using X-ray micro-computed tomography, scanning electron microscopy (SEM), and analytical scanning transmission electron microscopy (STEM). In addition, we used nanoindentation to determine how these features fine-tune the mechanical properties of the claw cuticle. We found that the inner layer of the claw cuticle—the endocuticle—contains amorphous calcium phosphate, while the outer layer—the exocuticle—is not mineralized and contains elevated amounts of bromine. While the chitin–protein fibers in crustacean exoskeletons generally shift their orientation, they are aligned axially in the claws of L. pallasii. As a consequence, the claw cuticle has larger elastic modulus and hardness in the axial direction. We show that amorphous calcium phosphate mineralization and the brominated cuticle are widespread in isopod crustaceans inhabiting terrestrial habitats. We discuss how the features of the claw cuticle may aid in minimizing the likelihood of fracture. Ultimately, our study points out the features that increase the durability of thin skeletal elements.

Effect of Different Mineralization Modes on Strengthening Calcareous Sand under Simulated Seawater Conditions

Calcareous sand, as a blow-fill or construction material, is widely used in island and reef construction projects in marine environments after treatment. When microorganism-induced mineralization is used to strengthen calcareous sand, salinity and other conditions in the marine environment will adversely affect microorganisms or their mineralization process. For this reason, the two environmental conditions created by deionized water and simulated seawater were introduced to explore their effects on the growth and urease activity of Sporosarcina pasteurii. Then, the changes in the permeability and mechanical strength of calcareous sand under different mineralization methods were compared by one-dimensional sand column tests. Finally, the reinforcement mechanism was compared and analyzed based on the results of scanning electron microscopy and X-ray diffraction tests. The results show that Sporosarcina pasteurii can induce carbonate and phosphate precipitation and mineralization to strengthen calcareous sand in simulated seawater. The mineralized products greatly reduce the permeability of calcareous sand and significantly improve the mechanical strength by wrapping calcareous sand particles, filling water seepage channels and cementing adjacent particles. The reinforcement effect of carbonate mineralization is better than that of phosphate mineralization, but phosphate mineralization has less impact on the environment during the treatment process.

Phosphates of the Streltsovsky ore field of South-Eastern Transbaikalia (Part 3)

The conclusions’ reliability of geologists who created the largest uranium ore base in the country on the territory of the Streltsovsky ore field (SOF) in the South-Eastern Transbaikalia, about the belonging of spatially isolated phosphate mineralization and powerful industrial mineralization to a final stage of Late Mesozoic tectonomagmatitic activation, is clarified. The relevance of the research lies in the need to study the geological materials at the SOF and the surrounding area to assess the prospects for involving in the exploitation of phosphate mineralization developed on the flanks of uranium deposits developed under the state program of the TOP. The object of study is the “blind” Argunskoye and Zherlovoye deposits and their western flanks on the surface, and the subject is the phosphate mineralization developed in the block of terrigenous-carbonate rocks. The purpose of the research is to clarify the time and features of the formation of phosphates, and the task is to assess the industrial significance of phosphate mineralization for decision-making. The methodology of scientific research is based on the interpretation of geological facts given in the literature and stock materials, use of concepts, terms, creation of hypotheses and their consequences, consistency of the comparison of which with the established facts determines the relatively high reliability of geological results. The author has used a descriptive method that takes into account a system of interrelated consistent positions, and a method of theoretical modeling, which raises the strategic goals of nature cognition to a higher scientific level. The results of the research are presented in three articles (parts). In the second part, phosphates of the region and SOF are characterized. It is established that the Talan manifestation of apatites belongs to the phosphate sorption-biogenic metalliferous formation of the Precambrian metamorphic rocks complex and combines the promising second and third most important industrial types of deposits. It is recommended to perform geological exploration at the evaluation stage and to test the electrothermal method for producing fused phosphate-magnesium fertilizers. In the third part, the known types of phosphogenesis and the genetic features of their manifestation in PSA are considered. Attention is drawn to the advantage of the recommended electrothermal method for processing apatite-carbonate and apatite-silicate rocks of the Talan manifestation

Phosphates of the Streltsovsky ore field of South-Eastern Transbaikalia (Part I)

The conclusions’ reliability of the geologists who created the largest uranium ore base in the country on the territory of the Streltsovsky ore field (SRP) in South-Eastern Transbaikalia, about the belonging of spatially isolated phosphate mineralization and powerful industrial mineralization to a single final stage of Late Mesozoic tectonomagmatitic activation, is clarified. The relevance of the research lies in the need to study the geological materials on the SRP and the adjacent area to assess the prospects for involving in the exploitation of phosphate mineralization developed on the flanks of uranium deposits developed under the state program of the TOP. The object of study is the “blind” Argunskoye and Zherlovoye deposits and their western flanks on the surface, and the subject is the phosphate mineralization developed in the block of terrigenous-carbonate rocks. The purpose of the research is to clarify the time and features of the formation of phosphates, and the task is to assess the industrial significance of phosphate mineralization to make a decision on the feasibility of additional study of this scarce raw material. The methodology of scientific research is based on the interpretation of geological facts given in the literature and stock materials, use of concepts, terms, creation of hypotheses and their consequences, consistency of the comparison of which with the established facts determines the relatively high reliability of geological results. We used a descriptive method that takes into account a system of interrelated consistent positions, and a method of theoretical modeling, which raises the strategic goals of nature cognition to a higher scientific level. The results of the research are presented in three articles (parts). The first part contains information about the structural and geological positions of the region, the ore field, and the geological structure of the Western tectonic block of the SRP and the Argun, as well as the Vent uranium deposits. It is established that phosphate mineralization is the product of metamorphic transformations of Riphean phosphorites and igneous apatites associated with the Middle Riphean moderately alkaline peridotite-gabbro-gabbrodiorite complex. Phosphate mineralization is older than the Late Mesozoic uranium and other types of industrial mineralization by at least 1 billion years

Phosphates of the Streltsovsky ore field of South-Eastern Transbaikalia (Part II)

The reliability of the conclusions of geologists who created the largest uranium ore base in the country on the territory of the Streltsovsky ore field (SRP) in South-Eastern Transbaikalia, about the spatially isolated phosphate mineralization and powerful industrial mineralization belonging to a single final stage of Late Mesozoic tectonomagmatitic activation, is clarified. The relevance of the research is the need to study the geological materials on the PSA and the surrounding area to assess the prospects for involving in the exploitation of phosphate mineralization developed on the flanks of uranium deposits developed under the state program of the TOP. The object of study is the “blind” Argun and Zherlovoe deposits and their western flanks on the surface, and the subject is the phosphate mineralization developed in the block of terrigenous-carbonate rocks. The purpose of the research is to clarify the time and features of the phosphates’ formation, and the task is to assess the industrial significance of phosphate mineralization to make a decision on the feasibility of additional study of this scarce raw material. The methodology of scientific research is based on the interpretation of geological facts given in the literature and stock materials, use of concepts, terms, creation of hypotheses and their consequences, consistency of the comparison of which with the established facts determines the relatively high reliability of geological results. The author has used a descriptive method that takes into account a system of interrelated consistent positions, and a method of theoretical modeling, which raises the strategic goals of nature cognition to a higher scientific level. The results of the research are presented in three articles (parts). The second part describes the characteristics of uranium-molybdenum deposits, phosphates of the region and PSA, and the Talan manifestation of apatites. It is established that the Talan manifestation, despite the limited volume of the estimated reserves, has extremely favourable conditions for the economic feasibility of its study and, possibly, industrial development. Phosphate mineralization belongs to the complex of Precambrian metamorphic rocks. Apatite-carbonate and apatite-silicate subtypes of the phosphate sorption-biogenic metalliferous formation combine the promising second and third most important industrial types of apatite deposits. It is recommended to perform geological exploration of the estimated stage on an area of 20 hectares, paying special attention to the development of technology for processing mineral raw materials and to test the electrothermal method for producing effective fused phosphate-magnesium fertilizers used in the project of the Seligdar mining and Chemical Complex