ALBERT

Description: Seafloor massive sulfide (SMS) deposits are increasingly seen as important marine metal resources for the future. A growing number of industrialized nations are involved in the surveying and sampling of such deposits by drilling. Drill ships are expensive and their availability can be limited; seabed drill rigs are a cost-effective alternative and more suitable for obtaining cores for resource evaluation. In order to achieve the objectives of resource evaluations, details are required of the geological, mineralogical, and physical properties of the polymetallic deposits and their host rocks. Electrical properties of the deposits and their ore minerals are distinct from their unmineralized host rocks. Therefore, the use of electrical methods to detect SMS while drilling and recovering drill cores could decrease the costs and accelerate offshore operations by limiting the amount of drilling in unmineralized material. This paper presents new data regarding the electrical properties of SMS cores that can be used in that assessment. Frequency-dependent complex electrical resistivity in the frequency range between 0.002 and 100 Hz was examined in order to potentially discriminate between different types of fresh rocks, alteration and mineralization. Forty mini-cores of SMS and unmineralized host rocks were tested in the laboratory, originating from different tectonic settings such as the intermediate-spreading ridges of the Galapagos and Axial Seamount, and the Pacmanus back-arc basin. The results indicate that there is a clear potential to distinguish between mineralized and non-mineralized samples, with some evidence that even different types of mineralization can be discriminated. This could be achieved using resistivity magnitude alone with appropriate rig-mounted electrical sensors. Exploiting the frequency-dependent behavior of resistivity might amplify the differences and further improve the rock characterization.

Description: Marine electromagnetic methods provide useful and independent measures for the identification and quantification of submarine gas hydrates. The resistivity of seafloor sediments, drawn from area-wide electromagnetic data, mainly depends on the sediment porosity and the nature of the pore fluid. Gas hydrates and free gas are both electrically resistive. The replacement of saline water, thus conductive pore water with resistive gas hydrate or free gas, increases the sediment resistivity and can be used to provide accurate saturation estimates if the background lithology is known. While seismic methods are predominantly used to study the distribution of submarine gas hydrates, a growing number of global field studies have demonstrated that the joint interpretation of marine seismic and electromagnetic methods improves the evaluation of submarine gas hydrate targets. This article discusses the relationship between resistivity and free gas/gas hydrate saturation levels, how the resistivity of the sediment may be measured and summarizes the status and results of current and past field studies.

Description: Reliable data are the base of all scientific analyses, interpretations and conclusions. Evaluating data in a smart way speeds up the process of interpretation and conclusion and highlights where, when and how additionally acquired data in the field will support knowledge gain. An extended SMART monitoring concept is introduced which includes SMART sensors, DataFlows, MetaData and Sampling approaches and tools. In the course of the Digital Earth project, the meaning of SMART monitoring has significantly evolved. It stands for a combination of hard- and software tools enhancing the traditional monitoring approach where a SMART monitoring DataFlow is processed and analyzed sequentially on the way from the sensor to a repository into an integrated analysis approach. The measured values itself, its metadata, and the status of the sensor, and additional auxiliary data can be made available in real time and analyzed to enhance the sensor output concerning accuracy and precision. Although several parts of the four tools are known, technically feasible and sometimes applied in Earth science studies, there is a large discrepancy between knowledge and our derived ambitions and what is feasible and commonly done in the reality and in the field.

Description: This open access book presents the results of three years collaboration between earth scientists and data scientists, in developing and applying data science methods for scientific discovery. The book will be highly beneficial for other researchers at senior and graduate level, interested in applying visual data exploration, computational approaches and scientifc workflows.