The importance of clay minerals and their origin is crucial to an understanding of the physico-chemical functions of the interface at the Earth’s surface. Their place is that of contact between the ...mineral world and the living world, plants and finally mankind. This contact zone is the realm of much of the environment as we see it today. If we can understand the way clays function in their interaction with plants, we can understand the major forces which shape our immediate environment. We see increasingly that human activity interacts with the plant and mineral interface through the use of more powerful chemicals, either by purposeful application of accidental dispersion. Knowledge of the origin and transformation of clay minerals, their dynamic response to changing chemistry, is the key to a rational use of this natural boundary which affects our lives. The information and the analysis presented here is an attempt to set trends of research in the direction of preventive and creative use of the plant – soil interface. Clays are the product of slow transformations of high temperature rocks into reactive, fine grained material. This material, once in the sphere of plant interaction, becomes highly reactive with transformation periods of tens to hundreds of years. The challenge of the future is to use these rapid responses to the benefit of mankind. This book aims to further a better understanding of such mechanisms, and it is thus destined for an audience of ecologists, pedologists, agronomists and other researchers involved in earth surface science
Craton destruction and related resources Zhu, Rixiang; Zhang, Hongfu; Zhu, Guang ...
International journal of earth sciences : Geologische Rundschau,
10/2017, Volume:
106, Issue:
7
Journal Article
Peer reviewed
Craton destruction is a dynamic event that plays an important role in Earth’s evolution. Based on comprehensive observations of many studies on the North China Craton (NCC) and correlations with the ...evolution histories of other cratons around the world, craton destruction has be defined as a geological process that results in the total loss of craton stability due to changes in the physical and chemical properties of the involved craton. The mechanisms responsible for craton destruction would be as the follows: (1) oceanic plate subduction; (2) rollback and retreat of a subducting oceanic plate; (3) stagnation and dehydration of a subducting plate in the mantle transition zone; (4) melting of the mantle above the mantle transition zone caused by dehydration of a stagnant slab; (5) non-steady flow in the upper mantle induced by melting, and/or (6) changes in the nature of the lithospheric mantle and consequent craton destruction caused by non-steady flow. Oceanic plate subduction itself does not result in craton destruction. For the NCC, it is documented that westward subduction of the paleo-Pacific plate should have initiated at the transition from the Middle-to-Late Jurassic, and resulted in the change of tectonic regime of eastern China. We propose that subduction, rollback and retreat of oceanic plates and dehydration of stagnant slabs are the main dynamic factors responsible for both craton destruction and concentration of mineral deposits, such as gold, in the overriding continental plate. Based on global distribution of gold deposits, we suggest that convergent plate margins are the most important setting for large gold concentrations. Therefore, decratonic gold deposits appear to occur preferentially in regions with oceanic subduction and overlying continental lithospheric destruction/modification/growth.
We use U–Pb dating of allanite and REE-rich epidote in three polymetamorphosed units from the Eastern Alps to constrain the timing of prograde metamorphism. All three units (Ennstal, Wölz and Rappold ...Complex) record several metamorphic cycles (Variscan, Permian and Eoalpine) and presently define an Eoalpine (Cretaceous) metamorphic field gradient from lower greenschist to amphibolite facies. For U–Pb data, a method is introduced to test the magnitude of
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Th disequilibrium and potentially approximate the Th/U ratio of the reservoir out of which allanite and REE-rich epidote grew. We also show that the modelled stability of epidote-group minerals in the REE-free MnNCKFMASH and MnNCKFMASHTO systems and REE-bearing systems is nearly identical. By combining the stability fields of (clino-)zoisite and epidote modelled in REE-free systems with known geothermal gradients for the region, REE-rich epidote growth is constrained to 200–450 °C and 0.2–0.8 GPa during prograde metamorphism. In the Rappold Complex, allanite cores yield a Variscan age of ca. 327 Ma. In the Ennstal and Wölz Complex, allanite growth during the Permian event occurred at ca. 279–286 Ma. Importantly, recrystallized allanite laths and REE-rich epidote overgrowths in samples from all three units yield prograde Eoalpine ages of ca. 100 Ma, even though these units subsequently reached different peak conditions, most likely at different times. This suggests that all units were buried roughly at the same time during the onset of Eoalpine continental subduction. This interpretation leaves room for the model proposing that diachronous peak metamorphic conditions reported for the field gradient may be related to the inertia of thermal equilibration rather than tectonic processes.
Mineral resources prediction and assessment is one of the most important tasks in geosciences. Geochemical anomalies, as direct indicators of the presence of mineralization, have played a significant ...role in the search of mineral deposits in the past several decades. In the near future, it may be possible to recognize subtle geochemical anomalies through the use of processing of geochemical exploration data using advanced approaches such as the spectrum-area multifractal model. In addition, negative geochemical anomalies can be used to locate mineralization. However, compared to positive geochemical anomalies, there has been limited research on negative geochemical anomalies in geochemical prospecting. In this study, two case studies are presented to demonstrate the identification of subtle geochemical anomalies and the significance of negative geochemical anomalies. Meanwhile, the opportunities and challenges in evaluating subtle geochemical anomalies associated with mineralization, and benefits of mapping of negative anomalies are discussed.
The annually laminated oil shale from the Eocene maar lake at Messel (Federal State of Hessen, Germany) provides unique paleoenvironmental data for a time interval of ~640 ka during the Paleogene ...greenhouse phase. As a consequence of orbitally controlled changes in the vegetation in the vicinity of the lake, the lacustrine laminites can now be astronomically tuned. Dating is based on the short eccentricity amplitude modulations of the regional pollen rain and their correlation to the astronomical La2010a/La2010d solutions in combination with a revised
40
Ar/
39
Ar age of a basalt fragment from a lapilli tuff section below the first lacustrine sediments. Depending on different newly suggested ages for the Fish Canyon sanidine used as monitor for neutron irradiation, the age for the eruption at Messel is between 48.27 ± 0.22 and 48.11 ± 0.22 Ma. This allows for the first time the exact correlation of a Paleogene lacustrine sequence to the marine record in Central Europe. The Messel oil shale becomes now slightly older than previously assumed and includes the Ypresian/Lutetian boundary that moves the base of the European Land Mammal Age Geiseltalian (MP 11) into the Lower Eocene. This opens a window for establishing an independent chronostratigraphic framework for Paleogene terrestrial records and their correlation to the marine realm. Furthermore, the study reveals that higher amounts of pollen from “wet” and thermophilous plants indicate less seasonal and more balanced precipitation and slightly higher temperatures during a well-expressed eccentricity minimum.
Mountains cover about a quarter of the world’s land surface, and directly support a significant proportion of the world’s population living within mountainous regions. Mountains provide water, timber ...and non-timber forest products, mineral resources, and many other food, fiber, and fuel products. Mountains also provide diverse ecosystems, in terms of both species and genetics, due to the topographic complexity in mountains increasing isolation and promoting speciation. Managing mountain regions for the sustainable delivery of critical goods and services requires an increasingly detailed understanding of mountain surface processes and regulation. The aim of this Guest Edited Collection is to provide a platform for interdisciplinary studies of mountain surface processes, and their responses to climate change and human activities.
Verschiedene Bioökonomie-Strategien zielen auf die Substitution fossiler Brennstoffe durch nachwachsende Rohstoffe. Jedoch ist auch die Produktion agrarischer Ressourcen im derzeitigen Modell der ...industriellen Landwirtschaft ein extraktives System, das auf die ständige Zufuhr externer Nährstoffe angewiesen ist. Nach einer historisch-theoretischen Analyse dieser Nährstoffflüsse geht der Beitrag auf den Nährstoff Phosphor bzw. den Rohstoff Phosphatgestein ein. Es zeigt sich, dass Phosphatgestein, jahrzehntelang eine „billige Massenware", ab 2007 zu einem strategischen Rohstoff wurde, wobei auch Analysen über ein mögliches Fördermaximum (Peak Phosphorus) um das Jahr 2030 entstanden sind. Anhand exemplarischer Strategien staatlicher und privater Akteure zum Umgang mit der neuen Situation wird deutlich, dass die Kontrolle über Phosphor-Flüsse zunehmend umkämpft ist. Der Beitrag argumentiert, dass Bioökonomie-Strategien bereits bestehende Auseinandersetzungen um die Phosphatversorgung verschärfen und globale Ungleichheiten verstärken, die unter anderem in Ernährungskrisen hervortreten. Technologische Erneuerungen, die auch im Rahmen der Bioökonomie vorangetrieben werden, erlauben nur eine bedingte Abkehr vom extraktiven Charakter der Landwirtschaft, können aber die Interessen dominanter Akteure sichern.
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•Digital ore deposit models enhance conventional models by integrating clearer prospecting indicators based on metallogenic theories. They vividly depict 3D geological, geochemical, ...and geophysical models, improving the understanding of underground ore distribution.•This study introduces convolutional neural networks (CNNs) as an efficient method within comprehensive mineral prediction models. Leveraging deep learning, it identifies potential mineral-rich regions through spatial data analysis.•Achieving three-dimensional mineral resource predictions requires precise data integration and understanding of ore-forming principles. Comprehensive models incorporating multi-source data greatly enhance prediction accuracy.•At the Zaozigou Gold Deposit in Gansu Province, combining digital ore deposit models with CNN-based three-dimensional predictions delineated two promising prospecting areas. This approach augments prediction accuracy and offers novel insights for mineral exploration.
With the depletion of surface mineral deposits, attention has shifted to deep mineral exploration prospecting. The emergence of three-dimensional digital ore deposit models, facilitated by the advancement of computer technology, has transformed traditional two-dimensional geological models into computer-recognizable numerical-symbolic digital models. This transformation allows qualitative geological concepts, originally expressed in natural language, to be quantitatively expressed, thereby enhancing the accuracy of deep mineral exploration. This paper first outlines the development from traditional ore deposit models to digital ore deposit models, asserting that digital ore deposit models can encompass a more comprehensive array of multidisciplinary geological information, including mineralogy, ore deposit types, structural geology, geochemistry, and geophysics. Building upon digital ore deposit models, a three-dimensional geological model is constructed, combining regional metallogenic regularities, identifying ore-forming favorable information, and conducting quantitative extraction. Subsequently, a comprehensive prospecting model is established, followed by the integration of deep learning methods for deep-seated mineral exploration, forming a unified system of quantitative prospecting methodology for hidden mineral deposits under the framework of geological prospecting models, three-dimensional geological modeling, and three-dimensional quantitative prospecting. Finally, using the Zaozigou gold deposit in Gansu Province as a case study, this approach is applied to mineral exploration prospecting, delineating prospective target areas and providing valuable reference for future exploration efforts.
Karstification plays a crucial role in forming magnificent scenery, and storing oil, natural gas, mineral resources, and water. Through the inspiration of karstification, a hierarchical layered ...double hydroxide (LDH) with funnel-like and cave-like structures (called Karst-LDH) is formed by the dissolution of acrylic acid/water solution. Meanwhile, the results of transmission electron microscopy (TEM) and scanning electron microscopy (SEM) show that Karst-LDH has complicated and interconnected internal pipe networks. The actual maximum phosphate adsorption capacity of Karst-LDH reaches 126.38 mg g
−1
due to the unique structures, protonation, ligand exchange, ion exchange, and hydrogen bonding, which is over ten times that of general LDH with a regular hexagonal structure. The results of isotherms and thermodynamics also indicate that Karst-LDH conforms to more heterogeneous and multilayer adsorption with a higher entropy-driven process. Karst-LDH exhibits good selectivity for chloride and nitrate ions. The change in the frontier orbital interaction between phosphate and different LDHs is a significant reason for quick macropore transmission, mesopore interception, and finally, phosphate storage in Karst-LDH. This work provides an efficient way for the design and fabrication of high adsorption performance materials with unique karst-type structures, which can be used for multiple fields potentially.
A funnel-like and cave-like Mg/Al layered double hydroxide (called Karst-LDH) has a high phosphate adsorption capacity and good selectivity for chloride and nitrate ions.
Carbonatites are proven significant repositories of several critical and strategic elements such as rare earth elements, niobium, thorium, and uranium. Owing to their economic significance, mapping ...of carbonatites and associated mineral deposits has occupied prominent place in mineral resource exploration programs. In this study an integrated approach was developed to map carbonatite and related mineral deposits in the Loe‐Shilman, Northwest Himalaya of Pakistan, using remotely sensed advance space‐borne thermal emission and reflection radiometer (ASTER) multispectral data and visible near infrared and short‐wave infrared (VNIR‐SWIR) spectral characteristics of minerals in these deposits. Several image enhancement techniques, including band ratio (i.e., B4/B3), principal component and minimum noise fraction transformation (PC6 and MNF5, respectively) helped in highlighting the targeted rocks. The results demonstrate the suitability of ASTER data for discriminating carbonatite related mineral deposits from other surrounding lithologies. Results obtained from these methods were validated through field observations in the area and further confirmed through petrographic and chemical analyses of collected specimens. Field data have also served as training data to perform a supervised classification, allowing further improvement of the mapping results. Moreover, the obtained results from the techniques used for exploring carbonatites and related mineral deposits were stacked together for comparison with each other, to check their sensitivities, and assess their efficiency and accuracy. Generally, all these methods successfully highlighted carbonatites and related mineral deposits; however, when used integratively they exhibit higher degree of accuracy, and has proven to be relatively rapid and cost‐effective.
ASTER‐VNIR‐SWIR data subjected to several image enhancement techniques helped in highlighting carbonatites and related minerals. The study demonstrate the suitability of ASTER data and integration of the various techniques used as a rapid and cost‐effective approach for discriminating carbonatite related mineral deposits from other surrounding lithologies.
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