Theses
Watkins, Sarah, 2003 (PhD). Geological ground-truthing of modelling iceberg trajectories in the North Atlantic: Present day and Last Glacial Maximum.
The below theses were obtained whilst CEMP was located at the University of East Anglia
Mutch, Tom, 2000 (PhD) Properties of Quaternary Deep-Sea Sediments: Proxies For dust Inputs?
Karloukovski, Vassil, 2000 (PhD) Magnetostratigraphy and Palaeomagnetism of the area around the Momchilgrad Palaeogene depression, the East Rhodope Massif, Bulgaria.
Posen, Paulette, 2000 (mPhil). Magnetostratigraphy of the Rhaetian in the UK: step towards global correlation.
Cox, Jon .M.S., 1999 (PhD). Coastal-Estuary Sediment Transfers: A Geochemical and Mineralogical Study of Sources, 271pp + appendices.
Hallum, David .F., 1995 (PhD). Palaeomagnetic Investigations of Early and Middle Pleistocene Sediments in East Anglia, U.K., 446pp.
Perkins, Andy .M., 1993 (PhD). Magnetic Studies of Speleothems, 244pp + appendices.
Geological ground-truthing of modelling iceberg trajectories in the North Atlantic: Present day and Last Glacial Maximum
Doctoral Thesis: Sarah Watkins, Jan, 2004
An increasing number of ocean modelling and proxy studies has provided evidence that, during the past, the thermohaline circulation may have existed in a different configuration to the present-day. Here, a twin approach is adopted, combining ocean model results and sediment proxy data, to investigate North Atlantic circulation at the present day and Last Glacial Maximum (LGM). Forcing fields from ocean general circulation models (OGCM) are used to drive an iceberg trajectory model, which investigates the effect of the surface circulation patterns on iceberg drift. Magnetic measurements of deep-sea sediments have been used to identify ice-rafted detritus (IRD), allowing reconstruction of iceberg trajectories. The magnetic properties of 321 present-day samples and 154 LGM samples have been measured, together with samples from potential source areas. Multivariate analysis of selected, diagnostic magnetic parameters is used to characterise the sediment and identify the main controls on sedimentation. For both time periods the clustering distinguishes lower-latitude, aeolian input west of Africa from other detrital sediment inputs to the north and west North Atlantic. Present-day inter-calibration of the iceberg model and magnetic data indicate that the iceberg model performs reasonably well. Three possible stable ocean circulation states during the LGM are investigated. Two states have formation of intermediate/deep water in the North Atlantic (with different formation sites, rates and sinking depths), the third has all deep water formation in the Southern Ocean. Of the three modelled ocean circulation states, the magnetic data support that with dominant deep water formation in the Southern Ocean. Both the LGM iceberg model results and the magnetic data question the dominant role of Hudson Bay in delivering large amounts of IRD to the LGM North Atlantic (outside of Heinrich events), instead indicating the greater importance of European and St. Lawrence sourced IRD.
Properties of Quaternary Deep-Sea Sediments: Proxies For Dust Inputs?
Doctoral Thesis: Tom Mutch, June, 2000
Magnetic measurements have been used as proxies for dust inputs to
marine sediments, particularly in pelagic settings located downwind from major
atmospheric dust sources. The potential for atmospheric dust to modify
modern-day climate has been known for many years; recent studies have
demonstrated the capacity of mineral dust to modulate the thermal structure of
the atmosphere on regional scales. Further, aeolian dust may exert some level
of control on global climate by influencing the radiative balance of the
atmosphere and land, and through the supply of micronutrients (especially
iron) to the ocean. The aim of this research is examine the efficacy of
magnetic properties as dust proxies in pelagic sediments from the late
Quaternary and the Holocene, and thus extend our understanding of the links
between dust, climate and sediment magnetism.
Detailed rock-magnetic and complementary mineralogical analyses of
sediments from three distinct ocean regions are presented here. Each was
selected for analysis on the basis of issues of measurement and interpretation
raised by the published literature. The Ontong Java Plateau, western
equatorial Pacific, was cored during Ocean Drilling Program Leg 130. Here,
magnetic measurements were carried out on material from three Sites (805, 806 
and
807). Similar analyses were also carried out on material from ODP Leg 108 Site
663, eastern equatorial Atlantic. Finally, magnetic measurements were used to
characterise the high-coercivity behaviour of synthetic magnetic powders and
material from potential dust source areas. Similar measurements were then
carried out on two North Atlantic cores, T88-9P and NEAP15K
,
from the late Quaternary and Holocene, respectively.
This study finds that the magnetic properties and records of aeolian
deposition at the Ontong Java Plateau and Site 663 are decoupled through the
effects of significant post-depositional alteration of magnetic minerals, via
reduction diagenesis. Further, it appears that the rate of equatorial
upwelling, through mediation of organic matter supply, may have controlled
these sediment magnetic records.
Results from core T88-9P, from the
North Atlantic, demonstrate that certain room- and low-temperature
measurements of HIRM can be used to differentiate the aeolian component from
ice rafted debris in such sediments. 
When
applied to Holocene core NEAP15K, the magnetic measurements revealed a
quasi-millennial cyclicity that may be related to changes in solar insolation.
COASTAL - ESTUARY SEDIMENT TRANSFERS: A GEOCHEMICAL AND MINERALOGICAL STUDY OF SOURCES
Doctoral Thesis: Jonathan M. S. Cox, 1999.
The Humber estuary, on the east coast of England, is a major site for the
accumulation of sediments, but their source is poorly understood. There
are three important potential sources of sediment to the Humber estuary: (i)
fluvial sediments derived from catchment erosion, (ii) rapid coastal erosion
of the Devensian glacial Holderness tills, and (iii) modern North Sea
sediments, which can be distinguished on the basis of their geochemical and
mineralogical properties. Bulk and particle size-fractionated samples of
the potential source materials and Humber estuary sediments have been
characterised using (i) heavy mineral and garnet geochemistry analysis, (ii)
conventional magnetic properties, (iii) magnetic properties of
inclusion-dominated sediments, and (iv) minor element sediment geochemistry,
in an attempt to understand the importance of each of these sources to the
Humber estuary sediments.
Qualitative and quantitative contribution estimates indicate that Humber
estuary sand sized sediments are derived almost exclusively from marine
sources. Source proportions of Humber estuary sediments were assigned
using least squares residual unmixing of the 63-125 mm and 125-250 mm
fractions of magnetic data sets. Source contribution estimates of 92%
Holderness till and 8% fluvial for the 63-125 mm fraction, and 98% Holderness
till and 2% fluvial for the 125-250 mm fraction were obtained. Modeling
indicated that the North Sea source does not contribute to Humber estuary sand
sized sediments, also shown by significant differences in the geochemistry of
Humber estuary and North Sea garnet assemblages. Fluvial sediments are
constrained to areas above the tidal limits and to the upper tidal river
sections.
The supply of sediments from the Holderness tills to the Humber estuary is
inferred to be via a direct, short-term process. A transport pathway for
sand sized material from the Holderness coast to the mouth of the Humber
estuary is defined in nearshore waters within 7 km of Spurn Head. The
transfer of fine-grained contaminated sediments from the Humber estuary into
the North Sea is shown, where they are diluted by uncontaminated sediments
derived from Holderness.
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PALAEOMAGNETIC INVESTIGATIONS OF EARLY AND MIDDLE PLEISTOCENE SEDIMENTS IN EAST ANGLIA, U.K.
Doctoral Thesis: David Frank Hallam, 1995.
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MAGNETIC STUDIES OF SPELEOTHEMS
Doctoral Thesis: Andrew Mark Perkins, 1993.
The Natural Remanent Magnetizations (NRMs) of rocks and sediments relate to past variations of the Earth's geomagnetic field (GMF). Studies of speleothems (cave deposits such as stalagmites) have shown that they often possess measurable NRMs. However, there have not been extensive studies of the magnetic minerals responsible for the NRM, nor in determining the type and origin of the NRM.
A selection of speleothems has been studied by palaeomagnetic and rock magnetic techniques to identify the magnetic minerals within them and the carriers of the NRMs. Electron microscope studies of extracted magnetic phases provide suggestions as to their origin. These studies have been combined with observations of speleothem surfaces to address the question of how the NRM is acquired.
The NRMs and magnetic mineralogy's of most speleothems are dominated by magnetite, with hematite and goethite present as accessories. Some samples are dominated by hematite. The bulk magnetic content of most speleothems does not vary and consequently there is only a single primary component of magnetization. However, there are exceptions. Rock magnetic data suggest that interaction between magnetic phases may be occurring and thus these data cannot be interpreted unambiguously in terms of magnetic grain size. Electron microscope studies have shown that the techniques for extracting and preparing magnetic extracts cannot be used on a quantitative basis. On a qualitative basis, however, detrital grains (<0.01microns to >>10microns, composed of magnetite, hematite and titanomagnetite), hexagonal or cubic grains (<0.1microns, composed of magnetite) and needle-like grains (<2microns, possibly goethite) have been observed.
A detrital remanent magnetization contributes to the NRM of speleothems and is probably more important than previously suggested. Detrital grains are introduced into speleothems either via floodwaters or through feedwaters. It is suggested that the NRM is acquired due to grains becoming trapped in depressions in the speleothem surface. Experiments suggest that, in the near-abscence of oxygen, inorganic precipitation of magnetite could occur during speleothem growth. Iron-chelating organic compounds could also introduce iron into caves. Further work is needed on de-chelation mechanisms, the transport of detrital and organic material into caves, the thermodynamic behaviour of iron at low temperatures and the oxygen content of waters in and entering caves.
The recent introduction of mass spectrometry for dating speleothems
suggests that the reliability of speleothems as records of past behavioural
features of the GMF could be assessed to a greater degree.
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