The Maricunga Belt (chilean Precordillera) and its hydrothermal alteration zones as revealed by multispectral remote sensing and field studies

Remote sensing techniques offer a unique chance to analyse and map wide or nearly inaccessable areas under certain geoscientific aspects in relatively short time and at low cost. Therefore geological field campaigns together with multispectral image analysis were carried out for the Maricunga Belt in the chilenean Precordillera, south of the regional mining settlements San Salvador and Potrerillos (Atacama). On the basis of Landsat-TM 5, ASTER, radar-based DGM-data and field mapping/sampling the lithological/structural characteristics of several OH-bearing hydrothermal alteration zones of mostly Neogene age have been investigated because of their high value for future exploration. The often  unknown regional tectonic framework which seems to have controlled the alteration dimensions are also discussed. In order to obtain  reasonable lithological classification criteria for the remote sensing data fundamental statistical selection rules like the optimum index factor  (OIF) were applied to the combination of single TM bands. Furthermore specific band ratios (5/7; 5/4, 5/1) and principal components were  utilized to enhance the spectral properties of the argillized, bleached clay- and/or silica-rich alteration surfaces. Additional spectral measurements were carried out for each representative lithological unit of the alteration zones to estimate the quality of the calculated classifications/ratios for geological mapping. In some cases complementary geochemical data has been studied in order to obtain direct clues for understanding the type of some detected hydrothermal alterations. Finally the achieved data was compiled in a geological map which shows more than 20 hydrothermally altered surfaces in relation to the regional geology and the specific tectonic framework. The influence of three major fault systems (the N-S orientated West Fissure System, the NE-SW orientated Inca De Oro System and a poorly described NW-SE System) for the setting of the alterations seems to be obvious

Structural analysis of the Arunta Block and Amadeus Basin (Central Australia) by means of digital remote sensing techniques and field data

Der proterozoische Arunta Block und das altpaläozoische Amadeus Basin zeichnen sich durch jeweils eigenständige lithologische Abfolgen und tektonische Deformationstypen aus. Der Kontaktbereich dieser intrakratonen Blöcke wirft seit Jahren Diskussionen hinsichtlich des tektonischen Baus auf: von hypothetischen weitreichenden Überschiebungsdecken (nappes) bis hin zu einfachen kleindimensionierten Störungen oder Verschleppungen (thrusts). Im Rahmen dieser Arbeit wird versucht, diese Elemente anhand von multispektralen Landsat-TM-Daten und Analysen von Luftbildern und ERS-1-Daten makroskopisch zu erfassen und zu deuten. Es ist möglich, Gesteinseinheiten und die unterschiedlichen Deformationsstile repräsentativer Untersuchungsgebiete zu differenzieren, sowie auf der Basis der topographischenKarten ein digitales Höhenmodell der Region zu erstellen, das die Zusammenhänge zwischen morphologischen Gegebenheiten vor Ort und imSatellitenbild in Bezug auf die Verbreitung von Lithologien und Störungszonen verdeutlicht. Auf diese Weise entsteht das Bild eines komplexen tektonischen Spannungsfeldes, das für jeden intrakratonen Block individuelle, zeitlich voneinander getrennt wirkende Ereignisse als Auslöser für die anzutreffenden Strukturen vorsieht.The Proterozoic Arunta Block and the younger late Palaeozoic Amadeus Basin each show significant lithological sequences and tectonic deformation styles. Since years the contact zone of these intracratonic blocks raises controversial discussions concerning its tectonic origin: from hypothetic widespread nappes to simple faults and thrusts of smaller dimension everything is taken into consideration. Within the scope of this paper it is attempted to detect their macroscopic pattern by applying multispectral and further remote sensing data analysis of aerial photographs, Landsat-TM and ERS-1data. It is possible to distinguish rock units and different deformation styles of representative areas as well as to create a digital elevation model of the region on the basis of topographic maps that elucidates the coherence of morphological features in place and in the satellite image as far as the propagation of lithologies and fault zones is concerned. It arises the picture of a complex tectonictension field, that contains individual tectonic events separated by time for each structure within the intracratonic blocks

Die Shoemaker und Strangways-Krater: Zwei Impaktstrukturen in Australien in der GIS-gestützten Analyse von Fernerkundungs- und Geländedaten

Die Berücksichtigung von Fernerkundungsdaten in geologischen Informationssystemen (GIS) bietet für die Erkundung von terrestrischen Impaktstrukturen neuartige Möglichkeiten. Am Beispiel der komplexen proterozoischen Impaktkrater Shoemaker und Strangways wird gezeigt, dass die Einbindung multispektraler Landsat TM-Daten, Radardaten (ERS-2), geophysikalischer Daten (Aeromagnetik, Aeroradiometrie), Geländebefunden und bereits vorhandener geologischer Karteninformation in ein GIS raumbezogene Abfragen gestattet und z.T. Wissenslücken schließen kann. So lassen sich ursprüngliche Kraterdurchmesser und Erosionsniveaus für beide Strukturen besser abschätzen

Field work in the Outback:Planning and processing a geological diploma mapping in Central Australia

Der Finke Gorge National Park liegt im Zentrum des Australischen Kontinents. Aufgrund der großen Dimensionen des Landes sind weite Teile nur unzureichend und kleinmaßstäblich geologisch kartiert. Im Rahmen dieser Arbeit sollte der Versuch unternommen werden, den National Park unter Zuhilfenahme von Fernerkundungsdaten, wie Landsat TM-, ASTER-Daten, hochauflösenden stereographischen Luftbildern, digitalen Geländemodellen (DGM) und Vegetationskarten großmaßstäblich zu kartieren (1:10000). Die vorliegende Arbeit knüpft an die Untersuchungen von BUDE & PRINZ (2003) an und soll diese durch Geländebefunde ergänzen. Darüber hinaus soll der Bericht Erfahrungen hinsichtlich der Planung und Durchführung einer derartigen geologischen Geländearbeit vermitteln.The Finke Gorge National Park is situated in the centre of the Australian continent. Due to the great dimension of the outback, most of its parts are mapped geologically at a small scale. In this work we try to produce a detailed 1:10000 geological map of the National Park by applying field methods supported by remote sensing data like Landsat TM-, ASTER-Data, high resolution stereographic aerial views, digital terrain modells (DTM) and detailed geobotanic vegetation maps. This study continues the efforts of BUDE & PRINZ (2003), as it includes ground proof for representative areas. Furthermore this report gives an idea of the essential preparations in the forefield of such a geological field campaign

Analysis of Unmanned Aerial System-Based CIR Images in Forestry—A New Perspective to Monitor Pest Infestation Levels

The detection of pest infestation is an important aspect of forest management. In the case of the oak splendour beetle (Agrilus biguttatus) infestation, the affected oaks (Quercus sp.) show high levels of defoliation and altered canopy reflection signature. These critical features can be identified in high-resolution colour infrared (CIR) images of the tree crown and branches level captured by Unmanned Aerial Systems (UAS). In this study, we used a small UAS equipped with a compact digital camera which has been calibrated and modified to record not only the visual but also the near infrared reflection (NIR) of possibly infested oaks. The flight campaigns were realized in August 2013, covering two study sites which are located in a rural area in western Germany. Both locations represent small-scale, privately managed commercial forests in which oaks are economically valuable species. Our workflow includes the CIR/NIR image acquisition, mosaicking, georeferencing and pixel-based image enhancement followed by object-based image classification techniques. A modified Normalized Difference Vegetation Index (NDVImod) derived classification was used to distinguish between five vegetation health classes, i.e., infested, healthy or dead branches, other vegetation and canopy gaps. We achieved an overall Kappa Index of Agreement (KIA) of 0.81 and 0.77 for each study site, respectively. This approach offers a low-cost alternative to private forest owners who pursue a sustainable management strategy

High-resolution classification of south patagonian peat bog microforms reveals potential gaps in up-scaled CH4 fluxes by use of Unmanned Aerial System (UAS) and CIR imagery

South Patagonian peat bogs are little studied sources of methane (CH4). Since CH4 fluxes can vary greatly on a small scale of meters, high-quality maps are needed to accurately quantify CH4 fluxes from bogs. We used high-resolution color infrared (CIR) images captured by an Unmanned Aerial System (UAS) to investigate potential uncertainties in total ecosystem CH4 fluxes introduced by the classification of the surface area. An object-based approach was used to classify vegetation both on species and microform level. We achieved an overall Kappa Index of Agreement (KIA) of 0.90 for the species- and 0.83 for the microform-level classification, respectively. CH4 fluxes were determined by closed chamber measurements on four predominant microforms of the studied bog. Both classification approaches were employed to up-scale CH4 closed chamber measurements in a total area of around 1.8 hectares. Including proportions of the surface area where no chamber measurements were conducted, we estimated a potential uncertainty in ecosystem CH4 fluxes introduced by the classification of the surface area. This potential uncertainty ranged from 14.2 mg·m-2· day-1 to 26.8 mg·m-2· day-1. Our results show that a simple classification with only few classes potentially leads to pronounced bias in total ecosystem CH4 fluxes when plot-scale fluxes are up-scaled.Fil: Lehmann, Jan R. K.. Westfalische Wilhelms Universitat; AlemaniaFil: Münchberger, Wiebke. Westfalische Wilhelms Universitat; AlemaniaFil: Knoth, Christian. Westfalische Wilhelms Universitat; AlemaniaFil: Blodau, Christian. Westfalische Wilhelms Universitat; AlemaniaFil: Nieberding, Felix. Westfalische Wilhelms Universitat; AlemaniaFil: Prinz, Torsten. Westfalische Wilhelms Universitat; AlemaniaFil: Pancotto, Veronica Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Kleinebecker, Till. Westfalische Wilhelms Universitat; Alemani

Historische Grundwissenschaften und die digitale Herausforderung

Unter Federführung von Eva Schlotheuber (Heinrich-Heine-Universität Düsseldorf / VHD-Unterausschuss "Geschichte in der digitalen Welt") und Frank Bösch (Zentrum für die Zeithistorische Forschungen Potsdam / VHD-Unterausschuss "Audiovisuelle Quellen") verabschiedete der VHD ein Grundsatzpapier zum Status der Historischen Grundwissenschaften mit dem Titel "Quellenkritik im digitalen Zeitalter: Die Historischen Grundwissenschaften als zentrale Kompetenz der Geschichtswissenschaft und benachbarter Fächer". Das Grundsatzpapier, in dem auch ein forschungsstrategisches Interesse an den Grundwissenschaften in der digitalen Transformation zum Ausdruck kommt, wurde auf H-Soz-Kult veröffentlicht und mit einem Diskussionsforum begleitet. Dazu wurde aus dem breiten Spektrum der Historischen Kulturwissenschaften eine Reihe in- und ausländischer Kolleginnen und Kollegen zur Kommentierung und Diskussion eingeladen, um die Debatte zu stimulieren

Open-Source Processing and Analysis of Aerial Imagery Acquired with a Low-Cost Unmanned Aerial System to Support Invasive Plant Management

Remote sensing by Unmanned Aerial Systems (UAS) is a dynamic evolving technology. UAS are particularly useful in environmental monitoring and management because they have the capability to provide data at high temporal and spatial resolutions. Moreover, data acquisition costs are lower than those of conventional methods such as extensive ground sampling, manned airplanes, or satellites. Small fixed-wing UAS in particular offer further potential benefits as they extend the operational coverage of the area under study at lower operator risks and accelerate data deployment times. Taking these aspects into account, UAS might be an effective tool to support management of invasive plant based on early detection and regular monitoring. A straightforward UAS approach to map invasive plant species is presented in this study with the intention of providing ready-to-use field maps essential for action-oriented management. Our UAS utilizes low-cost sensors, free-of-charge software for mission planning and an affordable, commercial aerial platform to reduce operational costs, reducing expenses with personnel while increasing overall efficiency. We illustrate our approach using a real example of invasion by Acacia mangium in a Brazilian Savanna ecosystem. A. mangium was correctly identified with an overall accuracy of 82.7% from the analysis of imagery. This approach provides land management authorities and practitioners with new prospects for environmental restoration in areas where invasive plant species are present