Topic Review
East China Sea Basin
The back-arc East China Sea Basin lies on extended continental crust at the leading edge of the Eurasian plate. Geology over the East China Sea Shelf Basin have been studied bits and pieces by various researchers over the past 20 years. This work is intended to provide a full review of the tectonic evolution over the East China Sea Basin. 
  • 1167
  • 30 Oct 2020
Topic Review
Carbonatite-Related REE Deposits
The rare earth elements (REEs) have unique and diverse properties that make them function as an “industrial vitamin” and thus, many countries consider them as strategically important resources. China, responsible for more than 60% of the world’s REE production, is one of the REE‐rich countries in the world. Most REE (especially light rare earth elements (LREE)) deposits are closely related to carbonatite in China. Such a type of deposit may also contain appreciable amounts of industrially critical metals, such as Nb, Th and Sc. According to the genesis, the carbonatite‐related REE deposits can be divided into three types: primary magmatic type, hydrothermal type and carbonatite weathering‐crust type. This paper provides an overview of the carbonatite‐related endogenetic REE deposits, i.e., primary magmatic type and hydrothermal type. The carbonatite‐related endogenetic REE deposits are mainly distributed in continental margin depression or rift belts, e.g., Bayan Obo REE‐Nb‐Fe deposit, and orogenic belts on the margin of craton such as the Miaoya Nb‐REE deposit. The genesis of carbonatite‐related endogenetic REE deposits is still debated. It is generally believed that the carbonatite magma is originated from the low‐degree partial melting of the mantle. During the evolution process, the carbonatite rocks or dykes rich in REE were formed through the immiscibility of carbonate-silicate magma and fractional crystallization of carbonate minerals from carbonatite magma. The ore‐forming elements are mainly sourced from primitive mantle, with possible contribution of crustal materials that carry a large amount of REE. In the magmatic-hydrothermal system, REEs migrate in the form of complexes, and precipitate corresponding to changes of temperature, pressure, pH and composition of the fluids. A simple magmatic evolution process cannot ensure massive enrichment of REE to economic values. Fractional crystallization of carbonate minerals and immiscibility of melts and hydrothermal fluids in the hydrothermal evolution stage play an important role in upgrading the REE mineralization. Future work of experimental petrology will be fundamental to understand the partitioning behaviors of REE in magmatic-hydrothermal system through simulation of the metallogenic geological environment. Applying “comparative metallogeny” methods to investigate both REE fertile and barren carbonatites will enhance the understanding of factors controlling the fertility.
  • 1010
  • 17 Nov 2020
Topic Review
Groundwater Withdrawal-Induced Land Subsidence
Land subsidence is probably one of the most evident environmental effects of groundwater pumping. Globally, freshwater demand is the leading cause of this phenomenon. Land subsidence induced by aquifer system drainage can reach total values of up to 14.5 m. The spatial extension of this phenomenon is usually extensive and is often difficult to define clearly. Aquifer compaction contributes to many socio-economic effects and high infrastructure-related damage costs. Currently, many methods are used to analyze aquifer compaction. These include the fundamental relationship between groundwater head and groundwater flow direction, water pressure and aquifer matrix compressibility. Such solutions enable satisfactory modelling results. However, further research is needed to allow more efficient modelling of aquifer compaction. Recently, satellite radar interferometry (InSAR) has contributed to significant progress in monitoring and determining the spatio-temporal land subsidence distributions worldwide. Therefore, implementation of this approach can pave the way to the development of more efficient aquifer compaction models. This entry presents a comprehensive review of models used to predict land surface displacements caused by rock mass drainage, as well as (2) recent advances and (3) a summary of InSAR implementation over recent years to support the aquifer compaction modelling process. Therefore, the study presented would be of benefit to readers who are interested in the topic of interaction between the human population and the hydrogeological system in different regions. The research presented allows readers to better understand the factors, developments and effects of groundwater drainage and thus facilitate large - scale risk assessment and preventive planning.
  • 845
  • 27 Oct 2020
Topic Review
The White Sea
The White Sea is a small shallow semi-closed sea in the North-West of Russia. It is strongly affected by induced tides, so the tidal motion dominates in the sea. Sea ice is seasonal and the water salinity is less than in the neighbouring Barents sea due to strong river discharge. In this entry, we focus on the sources of data on the Sea.
  • 687
  • 21 Jan 2021
Topic Review
Land Administration and Blockchain Technology
Transparency of processes is very crucial across all institutions. In land administration processes, this is particularly important given the multi-stakeholder involvement. This paper argues that transparency of land administration processes involves carrying out and sharing up-to-date information on ownership, value, and the use of land and all of its associated resources among related institutions, right holders and other stakeholders, including third parties, as well as, acting on the information in an open manner. To achieve this in Ghana, blockchain technology has been identified as a complementary tool to the Ghanaian land administration system. Blockchain technology refers to a fully distributed crypto-graphical system that captures and stores a consistent, immutable and linear event log of the transactions between networked actors. The study identifies that given the potentials of blockchain technology which include; decentralization of transaction to all connected stakeholders, the immutability of records, hashing of records that allows for quick access to both historical and current land transactions' data, as well as the blockchain smart contract among others, land administration processes of land tenure, land valuation, land use planning, and land development will benefit from openness, and transparency, and human error elimination. It will also eliminate fraud, and double sales of land among other land challenges identified in the Ghanaian land sector.  The study proposes that for real-time land up-date in land information across all the land sector divisions; land valuation division, land title registration, survey and mapping division, and the public and vested land management division, a permisionless public blockchain architecture be adopted for the Ghanaian land system. This is because, in comparison to the other blockchain architecture types, the permisionless public blockchain allows more transparency, decentralization, openness, integration, and also adheres to privacy and data protection laws. This study and its results are particularly important not only to the Ghanaian land sector and its stakeholders, but to all other land administration systems in the sub-Saharan Africa region given the similarities in land administration across the region. In the Ghanaian context however, the study's findings if implemented will affect the institutional relations and shared authorities between all stakeholders which include government agencies, local chiefs and individual landowners. This is because, land decisions and land data will not become shared responsibility of all stakeholders and not dependent on just some few stakeholders. A successful implementation of blockchain in Ghana's land administration will however depend on negotiations and consensus amongst the different land stakeholder, education of all stakeholders on the technology, and its impacts, as well as standardization in the land administration processes across the different land divisions. This is because, where there is no such standardization, there is a high possibility of inconsistencies and irregularities in the processes which can affect the efficient working of the blockchain system.
  • 630
  • 07 Jun 2021
Topic Review
Expert System for Earthquake Prediction
Earthquake is one of the most hazardous natural calamity. Many algorithms have been proposed for earthquake prediction using expert systems (ES). We aim to identify and compare methods, models, frameworks, and tools used to forecast earthquakes using different parameters. The analysis shows that most of the proposed models have attempted long term predictions about time, intensity, and location of future earthquakes. An investigation on different variants of rule-based, fuzzy, and machine learning based expert systems for earthquake prediction has been presented. Moreover, the discussion covers regional and global seismic data sets used, tools employed, to predict earth quake for different geographical regions. Bibliometric and meta-information based analysis has been performed by classifying the articles according to research type, empirical type, approach, target area, and system specific parameters.
  • 620
  • 03 Feb 2021
Topic Review
"Zorbas" on Southeastern Sicily
Over the last few years, several authors have presented contrasting models to describe the response of boulders to extreme waves, but the absence of direct observation of movements has hindered the evaluation of these models. The recent development of online video-sharing platforms in coastal settings has provided the opportunity to monitor the evolution of rocky coastlines during storm events. In September 2018, a surveillance camera of the Marine Protected Area of Plemmirio recorded the movement of several boulders along the coast of Maddalena Peninsula (Siracusa, Southeastern Sicily) during the landfall of the Mediterranean tropical-like cyclone (Medicane) Zorbas. Unmanned autonomous vehicle (UAV) photogrammetric and terrestrial laser scanner (TLS) surveys were performed to reconstruct immersive virtual scenarios to geometrically analyze the boulder displacements recorded in the video. Analyses highlighted that the displacements occurred when the boulders were submerged as a result of the impact of multiple small waves rather than due to a single large wave. Comparison between flow velocities obtained by videos and calculated through relationships showed a strong overestimation of the models, suggesting that values of flow density and lift coefficient used in literature are underestimated.
  • 606
  • 25 Aug 2021
Topic Review
Saline Lakes
Saltwater lakes around the world are drying at a rapid rate. These lakes are present in arid and semi-arid regions where evaporation exceeds precipitation. The Aral Sea and Lake Urmia are examples for such rapidly drying lakes. These two lakes have lost up to 90% of their former area in the past 50 years.  
  • 594
  • 28 Oct 2020
Topic Review
Amin Beiranvand Pour
My scholarly interests range widely, from mineral exploration to environmental issues such as geo-hazard, structural mapping, geothermal and geomorphic and coastal geology investigations. Subsequently, I have conducted several research projects for geological mapping, disaster management and environmental modeling using a variety of satellite remote sensing data such as the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Landsat Enhanced Thematic Mapper+ (ETM+), Landsat-8, Advanced Land Imager (ALI), Hyperion and Phased Array type L-band Synthetic Aperture Radar (PALSAR) satellite data in arid and semi-arid terrains, Antarctic, Arctic and tropical environments. 
  • 477
  • 10 Nov 2020
Topic Review
Antigorite is a Mg-rich 1:1 trioctahedral-structured layered silicate mineral of the serpentine group. Antigorite with layered structure can be used as a lubricant and friction reducing material to repair the friction pair of iron agent on line.
  • 464
  • 26 Oct 2020
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