Book Description

This dissertation, "Integrated Sedimentological, Geophysical and Geotechnical Study of Inner Shelf Sediments in Hong Kong" by Wing-yan, Connie, Mok, 莫穎恩, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled INTEGRATED SEDIMENTOLOGICAL, GEOPHYSICAL AND GEOTECHNICAL STUDY OF INNER SHELF SEDIMENTS IN HONG KONG Submitted by MOK WING YAN CONNIE for the degree of Master of Philosophy at The University of Hong Kong in November 2005 Previous work on a borehole drilled in the West Lamma Channel, Hong Kong has revealed a sedimentary sequence dating back to ca. 0.5 Ma with five interglacial- glacial cycles consistent with the Vostok ice core in Antarctica. In the present study, two new vibrocores located adjacent to the site were examined for their sedimentological, geophysical and geotechnical properties. The results obtained include (1) In-situ cone penetration test (CPT); (2) laboratory measurements of p- wave velocity, magnetic susceptibility, moisture content, density and sedimentological core logging; and (3) automated measurements of properties and collection of digital images using the GEOTEK multi-sensor core logging system with GEOSCAN. The properties of the sea-floor sediments were found to be related to both the depositional and post-depositional processes. Five marine units (M1 - M5) and three terrestrial units (T2 - T4) can be recognized. Because the Holocene M1 unit has never been sub-aerially exposed, the clayey silt is soft and saturated, and properties including moisture content, porosity, magnetic susceptibility, impedance and density differ from the pre-Holocene M2 to M5 units. This is attributed to the subaerial exposure of the M2 to M5 units during glacial period(s), usually resulting in a more desiccated upper part in comparison to the less desiccated lower part. Units T2 to T4 comprise sand and gravel and are different from the M2 to M5 units in their higher cone resistance, density, and p-wave velocity and their lower friction ratio, moisture content, porosity and impedance. The measurements of sedimentological, geotechnical and geophysical properties of seabed sediments have been found to be useful in providing information of the stratigraphy of seabed deposits and in constructing the history of Quaternary sea-level changes. The GEOTEK multi-sensor core logger with GEOSCAN provided fast and non-destructive measurements of physical properties of sediment cores as well as high-resolution colour digital images of split cores. The system is concluded to show great potential for supporting offshore ground investigation in addition to the reconstruction of Quaternary geological history of continental shelves. DOI: 10.5353/th_b3567517 Subjects: Marine sediments - China - Hong Kong Geology, Stratigraphic - Quaternary Sea level - China - Hong Kong