 |
A mixture of bacterial magnetosomes and
superparamagnetic magnetite. The bacterial magnetosomes are mostly
octahedral and prism-shaped forms. The long magnetite -blade is also
thought to be of bacterial (?) origin. The very fine-clumps of
grains are like typical superparamagnetic soil derived material. (width of
micrograph 0.9mm) {magnetic extract, TEM} |
Marine Quaternary, Bahamas, ODP hole 1006D. [M.W.
Hounslow] |
 |
Chain of bacterial magnetosome and clumps of
individual magnetosomes on a mica flay. The granulated texture on the
sample is the gold-coat on the sample, which obscures the individual
magnetosomes. {magnetic extract, field emission SEM} |
marine, Late Cretaceous Chalk, Culver Cliff,
Isle of Wight, UK. [M.W. Hounslow] |
 |
Octahedral, prism, bullet and booty-shaped
magnetosomes. {magnetic extract, TEM} |
Marine, Late Cretaceous Chalk, Culver Cliff,
Isle of Wight, UK. [M.W. Hounslow] |
 |
Various shaped and sized magnetosomes. The
large rounded grain on the right may be lithogenic in origin. The pitted
and irregular shapes of some magnetosomes, indicates that magnetosomes
have undergone mild dissolution within the sediment. (width of micrograph
1.35mm) {magnetic extract, TEM} |
Marine, Quaternary, Bahamas, ODP hole 1006D.
[M.W. Hounslow] |
 |
Long intact bacterial magnetosome chains,
with attendant, presumed magnetite blades. (width of micrograph 4.5mm)
{magnetic extract, TEM} |
Marine Quaternary, Bahamas, ODP hole 1006D. [M.W.
Hounslow] |
 |
Magnetosomes as satellite grains around
larger lithogenic particles. {magnetic extract, TEM} |
marine Quaternary, Owen Ridge, Indian Ocean
ODP Hole 722b. [B.A. Maher] |
 |
Intact chains of magnetosomes (presumed
magnetite ?), mostly as bullet or octahedral shaped. The membrane around
the grains may be the original bacterial membrane wall. {magnetic extract,
TEM} |
Iron age ditch fill (ie ~300-50BC),
Yarnton, Oxfordshire, UK. [M.W. Hounslow] |
 |
Magnetosome grains particularly rich in
octahedral forms. The irregular shapes of some magnetosomes, indicates
that they have undergone some dissolution . (width of micrograph 0.7mm)
{magnetic extract, TEM} |
Marine, Late Cretaceous Chalk, Seaford ,
Sussex, UK. [M.W. Hounslow] |
 |
Bacterial magnetosomes (smallest grains),
and two large rounded grains which are baryte (BaSO4) from
siliceous microfossils. The sponge-like object on the right is a
radiolarian fragment, with magnetosomes included within its porous
framework. This extract is rich in baryte (~30% by mass), which is
inferred to contain magnetic inclusions of unknown composition. These
inclusions cannot be imaged in conventional TEM. {magnetic extract, TEM} |
Quaternary pelagic ooze, Mascarene Plateau,
Indian Ocean, ODP Hole 709 [B.A. Maher] |
