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Topic Review
The UNESCO Site of the Chaîne des Puys
The tectono-volcanic ensemble of the Chaîne des Puys and the Limagne fault, which is part of the West European rift, was inscribed on the UNESCO World Heritage list in 2018 as the Chaîne des Puys–Limagne fault tectonic arena.
  • 349
  • 25 Sep 2023
Topic Review
Regional Geological of the Biga Peninsula
Biga Peninsula is a geologically diverse and complex peninsula that has been exposed to a series of tectonic events during its lengthy history. It represents the western section of the Sakarya Zone (S Pontide Domain) along the boundary between Gondwana and Laurasia and consists of numerous tectonic units, representing both continental and oceanic assemblages. The tectonic activity of the Biga Peninsula is primarily impacted by the motion occurring along the North Anatolian Fault Zone.
  • 340
  • 23 Oct 2023
Topic Review
Tectonic Evolution of the JLJB, North China Craton
The Jiao-Liao-Ji Belt (JLJB) is the most representative Paleoproterozoic orogenic belt in the North China Craton (NCC). The sedimentation, metamorphism and magmatism of the Ji’an Group and associated granites provide significant insights into the tectonic evolution of the JLJB. The rock assemblages indicate a transformation of the tectonic environment from a passive margin to an active continental margin following the onset of plate convergence and subduction. The A2-type gneissic granite (Qianzhuogou pluton) is formed in a subsequent back-arc basin extension setting at 2.20–2.14 Ga. The Ji’an Group was finally deposited in an active continental margin during the closure of a back-arc basin at 2.14–2.0 Ga. Then, the sediments were involved in a continent–arc–continent collision between the Longgang and Nangrim blocks at ~1.95 Ga. This process was accompanied by HP granulite-facies metamorphism at ~1.90 Ga. The subsequent exhumation and regional extension resulted in decompression melting during 1.90–1.86 Ga, producing metamorphism with an isothermal decompression clockwise P–T path. The resulting metapelites are characterized by perthite + sillimanite, and mafic granulites are characterized by orthopyroxene + clinopyroxene.
  • 333
  • 26 Jul 2023
Topic Review
Coal Measures Sandstone Reservoir in Xishanyao Formation
The reservoir physical properties, pore types, diagenetic characteristics and reservoir quality controlling effect of the Xishanyao formation coal measure sandstone in the southern margin of the Junggar basin were discussed in this study based on thin section observation, high pressure mercury injection, low-temperature nitrogen adsorption and scanning electron microscope observation. The result shows that the porosity and permeability of the sandstone are generally low with a medium-high texture maturity and low compositional maturity. The sandstone storage space is mainly composed of residual intergranular pores, secondary dissolution pores, inter-crystalline pores and micro-fractures. The diagenetic stage of coal measure sandstone is in the mesodiagenesis A1-A2 stage, and their diagenetic interaction types mainly include compaction, cementation and dissolution. The reservoir quality of the coal measure sandstone deteriorates by compaction due to high matrix content and plastic debris content. Because of the large amounts of organic acids generated during the thermal evolution of the coal measure source rock, the coal measure sandstone suffers from strong dissolution. The secondary dissolution pores formed by the massive dissolution of feldspar, lithic fragments and early carbonate cementation in the sandstone significantly improved the reservoir quality. In the coal measure sandstone, clay mineral cementation is the most developed cementation form, followed by quartz cementation and carbonate cementation. Although kaolinite cementation and dolomite cementation can generate a small number of inter-crystalline pores, cementation deteriorates the reservoir quality. The Xishanyao formation coal measure sandstone formed in a lacustrine-delta environment, and its composition and texture make it susceptible to the influence of compaction and dissolution during diagenesis.
  • 323
  • 31 Aug 2022
Topic Review
Rocks in Western Yunnan
The zircon U–Pb data indicated that the Santaishan serpentinized pyroxene peridotite (SSPP) was formed 186–190 Ma, and the Yingjiang hornblende pyroxenite (YHP) was formed 182–183 Ma. 
  • 315
  • 27 Oct 2023
Topic Review
Multi-Stage Sn-Polymetallic Mineralization
South Hunan, an important component of the Nanling polymetallic metallogenic belt, experienced a fairly long history of polycyclic tectonic evolution with multiple magmatic and hydrothermal events, during which a series of tungsten-tin polymetallic ore fields/deposits (e.g., Huangshaping, Shizhuyuan, Xitian, Xianghualing) were formed.
  • 303
  • 16 Sep 2022
Topic Review
List of Geological Groups of Great Britain
This is a sortable list of the groups into which the rock succession of Great Britain and surrounding seas is formally divided. Rock sequences are described by geologists by dividing them hierarchically thus: individual 'beds' of rock (or in the case of certain volcanic rocks, 'flows') are grouped into 'members', members are grouped into 'formations', formations into 'groups' and groups occasionally into 'supergroups'. Some groups are also subdivided into 'subgroups'. Not all of these hierarchical layers are necessarily present or defined within a particular rock succession. Many of these groups will be encountered as 'series' in older geological literature or indeed simply as the proper name e.g. 'Dalradian' or 'Millstone Grit' though care needs to be exercised as many of the names have or have had other meanings which may not coincide with the assemblage of rocks referred to formally through designation as a 'group'. Note that with all such stratigraphical terms as 'groups', 'formations' and 'members' it is standard practice to capitalise both the proper name and the 'term-word' as per the recommendation of the International Commission on Stratigraphy e.g. Wentnor Group and not Wentnor group. Notes:
  • 297
  • 11 Nov 2022
Topic Review
Measure the Height of Mount Everest
Mount Everest is the highest mountain in the world. First, we should know where is Mt. Everest located on the plateau of Tibet map. It is on the border of Nepal and Tibet(the Autonomous Region of China). The determination of the height of Mount Everest(HME) is one of the focuses of the geodetic community. The shallow layer method (SLM) based on the definition of the geoid can determine the gravity field inside the shallow layer. The orthometric height of Mount Everest (HME) is calculated based on SLM, in which the key is to construct the shallow layer model. The top and bottom boundaries of the shallow layer model are the natural surface of the Earth and the surface at a certain depth below the reference geoid, respectively. 
  • 272
  • 31 Jan 2024
Topic Review
Paludiculture in Latvia
Global climate change impact has increased in recent decades and put urgency on implementing effective climate change mitigation (CCM) activities. Rewetting of drained peatlands is an acknowledged measure to reduce GHG emissions from organic soils in the agriculture and land use sectors. Under waterlogged conditions, decomposition of organic matter in peat decreases, and emissions of CO2 are reduced. Thus, the soil carbon stock is saved, and wet management of the site reactivates carbon sequestration. To reach CCM targets, the first rewetting and paludiculture trials have been implemented in Latvia.
  • 250
  • 19 Dec 2023
Topic Review
Hornfels-like Rocks in Early Paleozoic Olkhon Collisional Orogen
Some metamorphic rocks discovered within the Olkhon terrane on the western side of central Lake Baikal (southeastern Siberia, Russia) are remarkable for their hornfels-like features, granular textures, and mafic compositions, with a typical mineral assemblage of Opx+Cpx+Amp+Pl+Ilm±Ol±Bt±Spl±Ti-Mag. The hornfels-like rocks lack any evident source of heat that would be responsible for the thermal alteration of the igneous protolith.
  • 199
  • 15 Nov 2023
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