Permafrost is a ubiquitous feature of arctic landmasses, and natural gas hydrate occurrence is widespread in the arctic and beneath the sea floor on continental slopes at all latitudes. The mechanical, thermal and hydraulic properties of the subsurface are profoundly modified by ice and hydrate. Nuclear magnetic resonance is a relatively recent addition to the measurement methods used to characterize recovered samples. This review shows how magnetic resonance has been used in two field studies to quantify frozen and unfrozen components of the sediment pore space, to understand the growth habit of ice and hydrate in rock and sediments, and to estimate hydraulic permeability.
Figures & Tables
New Techniques in Sediment Core Analysis
Marine sediment cores are the fundamental data source for information on seabed character, depositional history and environmental change. They provide raw data for a wide range of research including studies of climate change, palaeoceanography, slope stability, oil exploration, pollution assessment and control, seafloor survey for laying cables, pipelines and construction of seafloor structures. During the last three decades, a varied suite of new technologies have been developed to analyse cores, often non-destructively, to produce high-quality, closely spaced, co-located downcore measurements. These techniques can characterize sediment physical properties, geochemistry and composition in unprecedented detail. Palaeoenvironmentally significant proxies can now be logged at decadal, and in some cases, annual or sub-annual scales, allowing highly detailed insights into climatic history and associated environmental change. These advances have had a profound effect on many aspects of the Earth Sciences and our understanding of the Earth's history.
In this volume, recent advances in analytical and logging technology and their application to the analysis of sediment cores are presented. Developments in providing access to core data and associated datasets, and advances in data mining technology in order to integrate and interpret new and legacy datasets within the wider context of seafloor studies are also discussed.