{"title":"曼多加地区(喀麦隆高原南部)片麻岩上发育的红土的岩石学特征:两个持续分化的岩石动力学领域的证据","authors":"Rosalie Valerie Ngimbous, Brunot Nyeck, Paul-Desire Ndjigui","doi":"10.1007/s12517-024-11932-5","DOIUrl":null,"url":null,"abstract":"<p>This study was carried out in the weathering profile on gneiss in the Mandoga area (south Cameroon plateau), on the petrological characterization of the weathered phases. Gneiss is made up of quartz, feldspars, biotite, muscovite, garnet, kyanite, and zircon, with negative Eu anomaly (Eu/Eu* = 0.63). The profile shows three groups of phases: coarse saprolite at the bottom of the weathering horizon, the phases of the fine saprolite, and those of the uppermost part of the weathering profile. The mineralogical composition differs from the coarse saprolite to the top soil. All phases comprised kaolinite, quartz, and goethite. They characterize a pedoclimatic environment-rich in water, favorable to the stability of hydrated minerals. The negative Eu anomaly in all phases reflects the lithodependance of horizons at the expense of the gneiss, the parent rock. The Ce anomalies are linked to the pedodynamic conditions. In the same way, the behavior of REE in the different phases confirms the variation of the geochemical processes of the two pedodynamic domains. The phases from the fine saprolite are enriched in LREE than in HREE and match an overlapping of geochemical pedodynamic processes. Thus, the phases are marked by the geochemical signature along the weathering profile.</p>","PeriodicalId":476,"journal":{"name":"Arabian Journal of Geosciences","volume":null,"pages":null},"PeriodicalIF":1.8270,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Petrological features of laterites developed on gneiss in the Mandoga area (south Cameroon plateau): evidence of two continuously differentiating pedodynamic domains\",\"authors\":\"Rosalie Valerie Ngimbous, Brunot Nyeck, Paul-Desire Ndjigui\",\"doi\":\"10.1007/s12517-024-11932-5\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>This study was carried out in the weathering profile on gneiss in the Mandoga area (south Cameroon plateau), on the petrological characterization of the weathered phases. Gneiss is made up of quartz, feldspars, biotite, muscovite, garnet, kyanite, and zircon, with negative Eu anomaly (Eu/Eu* = 0.63). The profile shows three groups of phases: coarse saprolite at the bottom of the weathering horizon, the phases of the fine saprolite, and those of the uppermost part of the weathering profile. The mineralogical composition differs from the coarse saprolite to the top soil. All phases comprised kaolinite, quartz, and goethite. They characterize a pedoclimatic environment-rich in water, favorable to the stability of hydrated minerals. The negative Eu anomaly in all phases reflects the lithodependance of horizons at the expense of the gneiss, the parent rock. The Ce anomalies are linked to the pedodynamic conditions. In the same way, the behavior of REE in the different phases confirms the variation of the geochemical processes of the two pedodynamic domains. The phases from the fine saprolite are enriched in LREE than in HREE and match an overlapping of geochemical pedodynamic processes. Thus, the phases are marked by the geochemical signature along the weathering profile.</p>\",\"PeriodicalId\":476,\"journal\":{\"name\":\"Arabian Journal of Geosciences\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":1.8270,\"publicationDate\":\"2024-03-21\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Arabian Journal of Geosciences\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1007/s12517-024-11932-5\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"Earth and Planetary Sciences\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Arabian Journal of Geosciences","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1007/s12517-024-11932-5","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"Earth and Planetary Sciences","Score":null,"Total":0}
引用次数: 0
摘要
这项研究是针对曼多加地区(喀麦隆南部高原)片麻岩的风化剖面进行的,目的是分析风化相的岩石学特征。片麻岩由石英、长石、黑云母、黝帘石、石榴石、黝帘石和锆石组成,具有负 Eu 异常(Eu/Eu* = 0.63)。剖面显示了三组相:风化层底部的粗大边长岩相、细边长岩相和风化剖面最上部的相。从粗碳酸盐岩到表层土壤的矿物成分各不相同。所有岩相都由高岭石、石英和鹅膏石组成。它们代表了一个富含水的气候环境,有利于水合矿物的稳定。所有地层中的负 Eu 异常反映了地层的岩性依赖性,牺牲了母岩片麻岩。Ce异常与岩浆动力学条件有关。同样,REE 在不同岩相中的表现也证实了两个页岩动力域地球化学过程的差异。细粒矽卡岩相中的 LREE 含量比 HREE 含量丰富,这与地球化学过程的重叠相吻合。因此,沿风化剖面的地球化学特征对各相进行了标记。
Petrological features of laterites developed on gneiss in the Mandoga area (south Cameroon plateau): evidence of two continuously differentiating pedodynamic domains
This study was carried out in the weathering profile on gneiss in the Mandoga area (south Cameroon plateau), on the petrological characterization of the weathered phases. Gneiss is made up of quartz, feldspars, biotite, muscovite, garnet, kyanite, and zircon, with negative Eu anomaly (Eu/Eu* = 0.63). The profile shows three groups of phases: coarse saprolite at the bottom of the weathering horizon, the phases of the fine saprolite, and those of the uppermost part of the weathering profile. The mineralogical composition differs from the coarse saprolite to the top soil. All phases comprised kaolinite, quartz, and goethite. They characterize a pedoclimatic environment-rich in water, favorable to the stability of hydrated minerals. The negative Eu anomaly in all phases reflects the lithodependance of horizons at the expense of the gneiss, the parent rock. The Ce anomalies are linked to the pedodynamic conditions. In the same way, the behavior of REE in the different phases confirms the variation of the geochemical processes of the two pedodynamic domains. The phases from the fine saprolite are enriched in LREE than in HREE and match an overlapping of geochemical pedodynamic processes. Thus, the phases are marked by the geochemical signature along the weathering profile.
期刊介绍:
The Arabian Journal of Geosciences is the official journal of the Saudi Society for Geosciences and publishes peer-reviewed original and review articles on the entire range of Earth Science themes, focused on, but not limited to, those that have regional significance to the Middle East and the Euro-Mediterranean Zone.
Key topics therefore include; geology, hydrogeology, earth system science, petroleum sciences, geophysics, seismology and crustal structures, tectonics, sedimentology, palaeontology, metamorphic and igneous petrology, natural hazards, environmental sciences and sustainable development, geoarchaeology, geomorphology, paleo-environment studies, oceanography, atmospheric sciences, GIS and remote sensing, geodesy, mineralogy, volcanology, geochemistry and metallogenesis.