Detection of rare earth elements and rare earth oxides with hyperspectral spectroscopy : near-field and spaceborn investigations in preparation of the EnMAP mission

The continuously increasing demand for rare earth elements in technical components of modern technologies, brings the detection of new deposits closer into the focus of global exploration. One promising method to globally map important deposits might be remote sensing, since it has been used for a w...
Ausführliche Beschreibung

The continuously increasing demand for rare earth elements in technical components of modern technologies, brings the detection of new deposits closer into the focus of global exploration. One promising method to globally map important deposits might be remote sensing, since it has been used for a wide range of mineral mapping in the past. This doctoral thesis investigates the capacity of hyperspectral remote sensing for the detection of rare earth element deposits. The definition and the realization of a fundamental database on the spectral characteristics of rare earth oxides, rare earth metals and rare earth element bearing materials formed the basis of this thesis. To investigate these characteristics in the field, hyperspectral images of four outcrops in Fen Complex, Norway, were collected in the near-field. A new methodology (named REEMAP) was developed to delineate rare earth element enriched zones. The main steps of REEMAP are: 1) multitemporal weighted averaging of multiple images covering the sample area; 2) sharpening the rare earth related signals using a Gaussian high pass deconvolution technique that is calibrated on the standard deviation of a Gaussian-bell shaped curve that represents by the full width of half maxima of the target absorption band; 3) mathematical modeling of the target absorption band and highlighting of rare earth elements. REEMAP was further adapted to different hyperspectral sensors (EO-1 Hyperion and EnMAP) and a new test site (Lofdal, Namibia). Additionally, the hyperspectral signatures of associated minerals were investigated to serve as proxy for the host rocks. Finally, the capacity and limitations of spectroscopic rare earth element detection approaches in general and of the REEMAP approach specifically were investigated and discussed. One result of this doctoral thesis is that eight rare earth oxides show robust absorption bands and, therefore, can be used for hyperspectral detection methods. Additionally, the spectral signatures of iron oxides, iron-bearing sulfates, calcite and kaolinite can be used to detect metasomatic alteration zones and highlight the ore zone. One of the key results of this doctoral work is the developed REEMAP approach, which can be applied from near-field to space. The REEMAP approach enables rare earth element mapping especially for noisy images. Limiting factors are a low signal to noise ratio, a reduced spectral resolution, overlaying materials, atmospheric absorption residuals and non-optimal illumination conditions. Another key result of this doctoral thesis is the finding that the future hyperspectral EnMAP satellite (with its currently published specifications, June 2015) will be theoretically capable to detect absorption bands of erbium, dysprosium, holmium, neodymium and europium, thulium and samarium. This thesis presents a new methodology REEMAP that enables a spatially wide and rapid hyperspectral detection of rare earth elements in order to meet the demand for fast, extensive and efficient rare earth exploration (from near-field to space). Ausführliche Beschreibung

Autor*in:	Bösche, Nina Kristine - 1985- [verfasserIn] Kaufmann, Hermann Josef - 1949- [akademischer betreuerIn]
Hochschulschrift:	Dissertation ; Universität Potsdam ; 2015

Format:	E-Book
Sprache:	Englisch

Erschienen:	Potsdam: 2016

Schlagwörter:	Seltenerdmetall / Prospektion / Hyperspektraler Sensor / Fernerkundung
Formangabe:	Hochschulschrift

Umfang:	1 Online-Ressource (147 Blätter) ; Illustrationen, Diagramme, Karten

Weitere Ausgabe:	Erscheint auch als Druck-Ausgabe Bösche, Nina Kristine, 1985 -: Detection of rare earth elements and rare earth oxides with hyperspectral spectroscopy - Potsdam, 2015

Links:	Link aufrufen Volltext Volltext Link aufrufen Link aufrufen Link aufrufen

DOI / URN:	urn:nbn:de:kobv:517-opus4-85363

Katalog-ID:	860525252