Banded iron formations (BIFs) are iron oxide- and silica-rich chemical sedimentary rocks and the principal source of high-grade (HG) iron ore. Magnetic survey methods are commonly applied in the exploration for BIF-hosted iron ore deposits but the interpretation of total magnetic intensity (TMI) data is often complicated by the presence of strong remanent magnetization and anisotropy of magnetic susceptibility (AMS). This study evaluated a tri-axial fluxgate vector magnetometer system for ground-based high-resolution mapping of BIF-hosted HG iron ore deposits at a 16 ha site near Mary River, Baffin Island. Magnetometer orientation was measured using a MEMS (Micro Electro-Mechanical System) accelerometer and dual D-GPS receivers. 12-oriented block samples were collected for analysis of rock magnetic properties and supplemented with outcrop measurements using a hand-held susceptibility probe. The large (3 Gauss) dynamic range of the tri-axial vector magnetometer permitted mapping of HG magnetite ore zones, with TMI in excess of 400,000 nT. A 20 m-wide W-E trending HG zone and a narrow (<10 m) BIF zone were identified in RMV maps with distinctive dipole signatures. Within the HG zone a northwest-southeast oriented magnetic fabric was defined by linear magnetic lows that offset the strike of the HG ore zone and were interpreted as brittle faults or shear zones. The RMV orientation indicated the presence of strong bedding parallel magnetization, while its signal amplitude showed a wide variation between ore types and provided basis for ore grade differentiation. Paleomagnetic measurements revealed high Q ratios for hematite ores and strong AMS for BIF. The results from Mary River demonstrate that remanence and AMS effects are important in BIF-hosted iron ores and cannot be neglected in magnetic interpretation and inversion modelling of magnetic source bodies. / Thesis / Master of Science (MSc)

In the vicinity of the Žírovice village near Františkovy Lázně in West Bohemia there exists a striking gravimetric isometric negative anomaly. Similar gravimetric anomaly near Mýtina, about 17 km to the SE of Žírovice, was interpreted by Mrlina et al. (2009) as a Quaternary volcanic structure of a maar-diatreme type. It is possible that the Žírovice anomaly and some other similar anomalies in the Cheb Basin may also reflect Tertiary or Quaternary volcanic structures. For this reason we performed a detailed gravimetric and magnetometric survey, followed by geophysical modeling. The presence of a volcanic structure was not confirmed by this work, on the contrary, it was rather excluded. The anomaly was interpreted as a sunken tectonic 3D block/graben.

<p>Magnetic surveys are one of the principal geophysical methods employed to map the structure of basement rocks deeply buried below cover strata. In resource studies, aeromagnetic surveys are commonly acquired at regional scales (100-1000’s km2) while very few studies have attempted to resolve basement structures at site-scale (<10 >km2). In this study, high-resolution lake-based magnetic survey methods were evaluated for mapping of deeply-buried basement faults (Küçükçekmece Lagoon, Turkey; 6 km2) and a suspected meteorite impact crater (Charity Shoal, Lake Ontario; 9 km2). Total magnetic intensity (TMI) surveys were acquired using a single Overhauser magnetometer with 50-150 m line spacing. Interpretation of the magnetic data was aided by forward modelling of TMI data and depth to basement estimates using Euler and analytic signal methods. Total magnetic intensity (TMI) maps of Küçükçekmece Lagoon identify several north-northwest trending (340-350°) magnetic lineaments that are aligned with strike-slip faults mapped from offshore seismic data. The pattern of magnetic anomalies in the lagoon is consistent with extensional normal faulting of bedrock and lake sediments. Magnetic results from Charity Shoal reveal a large (>1400 nT) parabolic-shaped magnetic anomaly centered over the crater basin and an annular magnetic high (40-50 nT) corresponding with the basin rim. Modelling results exclude the origin of the CSS as a shallow glacial erosional or karst sinkhole feature and are most consistent with a pre-Paleozoic meteorite impact in the Precambrian basement.</p> / Master of Science (MSc)

À l’heure actuelle, la prospection magnétique est reconnue comme une méthode efficace pour répondre à des problématiques archéologiques en partie du fait de sa capacité à détecter les structures enfouies (bâtiments, fosses, canaux, etc,…). Elle permet de mettre en évidence et de localiser avec précision les structures et elle est donc une aide précieuse avant le début des opérations de fouilles. Notre travail rend compte de cartographies magnétiques effectuées sur trois sites archéologiques en Syrie (Al-Rawda, Sh’airat, Malhat Ed-Deru) en utilisant deux méthodes de cartographie magnétique à différents niveaux de résolution. La première méthode (à la perche) permet de couvrir de grandes surfaces rapidement et la deuxième méthode (à la luge), plus lente, permet de mieux imager les structures enfouies. Ces méthodes fournissent des plans urbanistiques des villes circulaires du troisième millénaire avant J.C. Les opérateurs de méthodes potentielles et la modélisation ont permis de caractériser la géométrie des structures aimantées. / Currently, magnetic surveying is recognized as an effective method to address archaeological issues in part because of its ability to detect buried structures (buildings, pits, channels, etc ...). It allows identifying and accurately locating structures and is therefore a valuable aid before the commencement of excavation. Our work reports on magnetic mapping done at three archaeological sites in Syria (Al-Rawda, Sh’airat, Malhat Ed-Deru) using two methods of magnetic mapping at different levels of resolution, The first method (Backpack) allows to cover large areas quickly and the second method (Sledge), slower, allows better imaging of buried structures. These methods have provided urban planning circular cities of the third millennium BC. The modeling method swapped to characterize the magnetic sources.

No description available.

<p>Small, low cost Autonomous underwater vehicles (AUVs) provide ideal platforms for shallow water survey, as they are capable of unmanned navigation and can be programmed to acquire data at constant depth, or constant altitude above the seabed. AUVs can be deployed under most sea states and are unaffected by vessel motions that often degrade sonar and magnetometer data quality. The integration of sonar and magnetometer sensors on AUV’s is challenging, however, due to limited payload and strong magnetic fields produced by the vehicle motor.</p> <p>In this study, a Marine Magnetics Explorer Overhauser magnetometer was mated to a portable AUV (OceanServer Iver2) creating the first practical AUV- deployed magnetic survey system. To eliminate magnetic interference from the AUV, the magnetometer was tethered to the AUV with a 5 m tow cable, as determined by static and dynamic instrument testing. The results of the magnetic tests are presented, along with field data from a shallow water test area in Lake Ontario near Toronto, Canada. AUV-acquired magnetic survey data were compared directly with a conventional boat-towed magnetic survey of the same area. The AUV magnetic data were of superior quality despite being collected in rough weather conditions that would have made conventional survey impossible. The resulting high-resolution total magnetic intensity and analytic signal maps clearly identify several buried and surface ferrometallic targets that were verified in 500-kHz side- scan sonar imaging and visual inspection by divers.</p> / Master of Science (MSc)

Wetland sites provide important knowledge about settlement history and historical infrastructure in the form of buried archaeological features. However, the subsurface is difficult to access, e.g. due to high groundwater levels or unstable sediments, making archaeological excavation difficult and the conservation of recovered artefacts, e.g. timbers, is expensive. In addition, one of the aims of heritage conservation is to disturb structures in such contexts as little as possible as part of preserving. Therefore, alternative non- and minimal-invasive methods, e.g. geophysical prospection and vibra-coring, are used for exploration. However, geophysical surveys face the issue of inaccurate depth values and rely on sufficient contrasts in the measured physical parameters. Vibra-coring allows direct access to the sediments, but again gives inaccurate depth values due to high compaction rates. For this reason, the implementation of alternative methods and the development of new methodical approaches to wetland site exploration are of extraordinary importance. One such wetland site is the Fossa Carolina, an early medieval canal that today is partially buried. Located in Southern Germany next to Treuchtlingen, south of Nuremberg, the canal was intended at the time to provide a navigable link between the Rhine-Main and Danube basins by bridging the European watershed. In the research for this thesis, direct push sensing was used as an alternative exploration technique to explore the site. In this method, various probes are pushed into the unconsolidated subsoil and the parameters are measured in situ with high depth accuracy. (i) Therefore, the colour logging tool (CLT) and the electrical conductivity (EC) probe were applied. (ii) In order to record archaeological structures and features, the soundings were distributed closely along a transect using an adaptive exploration strategy, thus recording a high-resolution cross-section of the structure. (iii) These prospections were integrated into a spatial-hierarchical multi-method approach by combining direct push sensing with geophysical survey and vibra-coring, inter alia. (iv) Thus, a deeply buried section of the Fossa Carolina (West-East Section) was explored, demonstrating at least one-way navigability and revealing the backfill stratigraphy. (v) Furthermore, the approach used helped to clarify the nature of conspicuous magnetic anomalies in the area adjacent to the canal. In the Northern and North-Eastern Sections, magnetic anomalies provided evidence of water-supplying structures. The exploration of these structures revealed an Early Holocene structure in the North-Eastern Section and a historic gravel road in the Northern Section. (vi) Additionally, a strong magnetic anomaly with a course parallel to the canal in the Northern Section could be temporally and stratigraphically associated with the construction of the canal. Thus, for the first time, a larger remnant of the construction process outside the canal could be identified, even if the origin could not be conclusively clarified. (vii) In a broader context, the in situ direct push cross-sections were integrated into a 3D modelling approach for the entire Fossa Carolina to quantify the excavation volume. (viii) The methodological approach was successfully applied to a wetland site at Pestenacker in Southern Germany to collect evidence for Holocene floodplain dynamics in the Late Neolithic settlement. Finally, the thesis demonstrates the enormous methodological potential of direct push sensing for the exploration of buried archaeological sites. In particular, the colour logging tool is proving to be extremely effective, further enhanced by the intelligent combination in multi-method approaches. This is confirmed by the significant results obtained at Fossa Carolina that shed new light on the canal{'}s navigability, water supply, and construction structure. Overall, this thesis demonstrates the valuable contribution that direct push methods can make to geoarchaeological research. It both introduces a new methodological approach and provides new empirical evidence concerning the construction of an example of early medieval infrastructure.:Preface Acknowledgements Abstract Kurzfassung Contents List of Figures List of Tables Acronyms and Symbols 1 Introduction 1.1 Geoarchaeological exploration in wetlands: possibilities and challenges 1.1.1 Proven exploration methods 1.1.2 Direct push sensing 1.1.3 Exploration strategies 1.2 The study site 1.2.1 The Fossa Carolina - State of the art in brief 1.2.2 Natural settings 1.3 Aims of the thesis 2 Published Studies 2.1 Minimalinvasive Direct-push-Erkundung in der Feuchtboden(geo)archäologie am Beispiel des Karlsgrabens (Fossa Carolina) 2.2 Non-invasive prospection techniques and direct push sensing as high-resolution validation tools in wetland geoarchaeology – Artificial water supply at a Carolingian canal in South Germany? 2.3 High-Resolution Direct Push Sensing in Wetland Geoarchaeology—First Traces of Off-Site Construction Activities at the Fossa Carolina 2.4 3D-Modelling of Charlemagne’s Summit Canal (Southern Germany)—Merging Remote Sensing and Geoarchaeological Subsurface Data 2.5 A hydrological tipping point and onset of Neolithic wetland occupation in Pestenacker (Lech catchment, S Germany) 3 Discussion 3.1 Direct push sensing for wetland exploration 3.1.1 High-resolution direct push sensing cross-sections 3.1.2 Integration and comparison of direct push sensing in a spatially hierarchical multi-method approach 3.1.3 Direct push colour logging tool (CLT) data for ground truthing 3.1.4 Perspectives on direct push sensing in geoarchaeology 3.2 Results of the exploration of the Fossa Carolina 3.2.1 Chronostratigraphic recording in the West-East and Northern Sections 3.2.2 Characteristics of the canal construction in the West-East and Northern Sections 3.2.3 Validation of off-canal structures in the Northern and North-Eastern Sections 3.2.4 Water supply for the Fossa Carolina 3.2.5 Pending issues in the study of the Fossa Carolina 4 Conclusion References Appendix A1 - Author publications A2 - Article contribution A3 - Declaration of originality A4 - Bibliographic description / Feuchtgebiete bergen durch begrabene archäologische Strukturen wichtige Erkenntnisse zur Siedlungsgeschichte und historischen Infrastruktur. Schwierige Untergrundverhältnisse, z. B. durch hohen Grundwasserspiegel oder instabile Sedimente, erschweren jedoch archäologische Ausgrabungen und die Konservierung der geborgenen Artefakte, z. B. Hölzer, verursacht hohe Kosten. Darüber hinaus ist ein Ziel der Bodendenkmalpflege, archäologische Strukturen so wenig wie möglich zu beeinträchtigen und sie in situ zu erhalten. Daher werden alternative nicht- und minimal-invasive Methoden, z. B. geophysikalische Prospektionen und Rammkernsondierungen, zur Exploration eingesetzt. Bei geophysikalischen Untersuchungen ergeben sich jedoch Schwierigkeiten durch ungenaue Tiefenwerte und die Methoden sind auf ausreichende Kontraste der gemessenen physikalischen Parameter angewiesen. Rammkernsondierungen ermöglichen einen direkten Zugriff auf die Sedimente, erzeugen jedoch wiederum ungenaue Tiefenwerte durch hohe Kompaktionsraten. Aus diesem Grund sind die Implementierung alternativer Methoden und die Entwicklung neuer methodischer Ansätze für die Erforschung von Feuchtgebietsstandorten von herausragender Bedeutung. Die Fossa Carolina, ein frühmittelalterlicher, heute teilweise verschütteter Kanal, ist ein solcher Standort. Das Bauwerk befindet sich in Süddeutschland in der Nähe von Treuchtlingen, südlich von Nürnberg und sollte eine schiffbare Verbindung zwischen dem Rhein-Main- und dem Donaueinzugsgebiet herstellen, indem es die europäische Hauptwasserscheide überbrückte. Zur Erkundung des Bauwerks wurde als Alternative die in situ Direct-Push-Methode eingesetzt. Bei dieser Methode werden verschiedene Sonden in den unkonsolidierten Untergrund gedrückt und die Parameter in situ tiefengenau gemessen. (i) Dabei kamen die Farbsonde, engl. colour logging tool (CLT), und die Sonde zur Messung der elektrischen Leitfähigkeit, engl. electrical conductivity (EC) probe, zum Einsatz. (ii) Zur Erfassung archäologischer Strukturen und Befunde wurden die Sondierungen mit einer adaptiven Erkundungsstrategie auf einem Transekt engmaschig verteilt und somit ein hochaufgelöster Querschnitt des Bauwerks erfasst. (iii) Darüber hinaus wurden diese Prospektionen in einen räumlich-hierarchischen Multimethodenansatz integriert, indem in situ Direct-Push-Sondierungen mit z. B. geophysikalischen Erkundungen und Rammkernsondierungen kombiniert wurden. Somit wurde (iv) ein tiefliegender, begrabener Abschnitt der Fossa Carolina im West-Ost-Bereich erkundet, dort die Schiffbarkeit für mindestens eine Schiffsbreite nachgewiesen und die Sedimentstratigraphie der Verfüllung beschrieben. Weiterhin wurde der Ansatz genutzt, um magnetische Anomalien im Umfeld des Kanals zu prospektieren. (v) Im nördlichen und nordöstlichen Bereich lieferten magnetische Anomalien Hinweise auf wasserzuführende Bauwerke im Untergrund. Die Erkundung ergab eine frühholozäne Struktur im nordöstlichen Bereich und eine historische Schotterstraße im nördlichen Bereich. (vi) Weiterhin konnte eine starke magnetische Anomalie mit parallelem Verlauf zum Kanal im nördlichen Bereich zeitlich und stratigraphisch dem Bauwerk zugeordnet werden. Somit konnte zum ersten Mal eine größere Spur des Baus außerhalb des Kanals nachgewiesen werden, auch wenn die Entstehung nicht abschließend geklärt werden konnte. (vii) Im übergeordneten Kontext konnten die Daten der in situ Direct-Push-Transekte in einen 3D-Modellierungsansatz für die gesamte Fossa Carolina zur Quantifizierung des Aushubs integriert werden. (viii) Neben der Erforschung der Fossa Carolina wurde der methodische Ansatz zusätzlich an einem Feuchtgebietsstandort bei Pestenacker in Süddeutschland angewendet, um Informationen über die holozäne Auendynamik an der spätneolithischen Siedlung zu gewinnen. Schlussendlich belegt die Dissertation das enorme methodische Potential der in situ Direct-Push-Erkundungen für die Prospektion von Bodendenkmälern. Dabei erweist sich insbesondere die Farbsonde als äußerst wirkungsvoll, was durch die gezielte Kombination in multi-methodischen Ansätzen noch verstärkt wird. Dies wird durch die aussagekräftigen Ergebnisse an der Fossa Carolina belegt, mit deren Hilfe insbesondere neue Erkenntnisse zur Schiffbarkeit, Wasserzuführung und Baustruktur gewonnen werden konnten. Insgesamt demonstriert diese Dissertation den wertvollen Beitrag, den in situ Direct-Push-Methoden zur geoarchäologischen Forschung leisten können. Sie präsentiert sowohl einen neuen methodischen Ansatz als auch neue empirische Erkenntnisse zu einem frühmittelalterlichen Bauwerk.:Preface Acknowledgements Abstract Kurzfassung Contents List of Figures List of Tables Acronyms and Symbols 1 Introduction 1.1 Geoarchaeological exploration in wetlands: possibilities and challenges 1.1.1 Proven exploration methods 1.1.2 Direct push sensing 1.1.3 Exploration strategies 1.2 The study site 1.2.1 The Fossa Carolina - State of the art in brief 1.2.2 Natural settings 1.3 Aims of the thesis 2 Published Studies 2.1 Minimalinvasive Direct-push-Erkundung in der Feuchtboden(geo)archäologie am Beispiel des Karlsgrabens (Fossa Carolina) 2.2 Non-invasive prospection techniques and direct push sensing as high-resolution validation tools in wetland geoarchaeology – Artificial water supply at a Carolingian canal in South Germany? 2.3 High-Resolution Direct Push Sensing in Wetland Geoarchaeology—First Traces of Off-Site Construction Activities at the Fossa Carolina 2.4 3D-Modelling of Charlemagne’s Summit Canal (Southern Germany)—Merging Remote Sensing and Geoarchaeological Subsurface Data 2.5 A hydrological tipping point and onset of Neolithic wetland occupation in Pestenacker (Lech catchment, S Germany) 3 Discussion 3.1 Direct push sensing for wetland exploration 3.1.1 High-resolution direct push sensing cross-sections 3.1.2 Integration and comparison of direct push sensing in a spatially hierarchical multi-method approach 3.1.3 Direct push colour logging tool (CLT) data for ground truthing 3.1.4 Perspectives on direct push sensing in geoarchaeology 3.2 Results of the exploration of the Fossa Carolina 3.2.1 Chronostratigraphic recording in the West-East and Northern Sections 3.2.2 Characteristics of the canal construction in the West-East and Northern Sections 3.2.3 Validation of off-canal structures in the Northern and North-Eastern Sections 3.2.4 Water supply for the Fossa Carolina 3.2.5 Pending issues in the study of the Fossa Carolina 4 Conclusion References Appendix A1 - Author publications A2 - Article contribution A3 - Declaration of originality A4 - Bibliographic description