magnetic polarity
184
netism of geological features, which then reveal themselves by magnetic
anomalies.
magnetic polarity the converging of the magnetic lines of force in a dipole, with
a magnetic north and a magnetic south pole. According to the convention
that the northwards pointing end of a compass-needle is a magnetic north
pole, the earth's dipole has its (attracting) magnetic south pole near the geographical north pole and its magnetic north pole near the geographical
south. However, this polarity is not permanent. Studies of the remanent
magnetism induced by the magnetic (earth) field in ferromagnetic rocks at the
time of their formation reveal that magnetic polarity reversals have occurred
many times in the geologic past. Based upon these reversals, a polarity time
scale has been established.
magnetic polarity reversal ~magnetic polarity.
magnetic tags ~tagging.
magnetometer an instrument used for measuring earth magnetic field intensity. Magnetometers may measure the vertical component of the magnetic
field, or the horizontal component sometimes the total field is measured.
~magnetic (earth) field.
magnetostratigraphy stratigraphy based on paleomagnetic signatures. During
sediment deposition or cooling of molten rock, ferromagnetic minerals orientate themselves according to the existing magnetic field. The last 4.5 million years include four magnetic epochs (chrons) from old to young: the
Gilbert reversed, the Gauss normal, the Matuyama reversed, and the (presentday) Brunhes normal epoch. ~stratigraphic hierarchy, magnetic polarity and magnetic
(earth) field.
magnetotaxis orientation of organisms possessing magnetic crystals (some bacteria, dolphins, some birds) in the magnetic (earth) field.
Malacostraca class of the subphylum Crustacea (phylum Arthropoda), containing
most of the Crustacea including woodlice, sandhoppers, crabs, shrimps, and
lobsters. For general description of body structure ~Crustacea. The body of
the Malacostraca has basically 19 segments of which five compose the head,
eight segments form the thorax (sometimes covered by the carapace), and the
remaining six form the abdomen with telson. The segments each bear one
pair of appendages. On the head are two pairs of antennae and a pair of
stalked eyes. In the more primitive forms, all thoracic appendages are similar and used as walking legs; in others the first one, two or three pairs are
changed into maxillipeds. The abdominal appendages are smaller, and adapt-
184
netism of geological features, which then reveal themselves by magnetic
anomalies.
magnetic polarity the converging of the magnetic lines of force in a dipole, with
a magnetic north and a magnetic south pole. According to the convention
that the northwards pointing end of a compass-needle is a magnetic north
pole, the earth's dipole has its (attracting) magnetic south pole near the geographical north pole and its magnetic north pole near the geographical
south. However, this polarity is not permanent. Studies of the remanent
magnetism induced by the magnetic (earth) field in ferromagnetic rocks at the
time of their formation reveal that magnetic polarity reversals have occurred
many times in the geologic past. Based upon these reversals, a polarity time
scale has been established.
magnetic polarity reversal ~magnetic polarity.
magnetic tags ~tagging.
magnetometer an instrument used for measuring earth magnetic field intensity. Magnetometers may measure the vertical component of the magnetic
field, or the horizontal component sometimes the total field is measured.
~magnetic (earth) field.
magnetostratigraphy stratigraphy based on paleomagnetic signatures. During
sediment deposition or cooling of molten rock, ferromagnetic minerals orientate themselves according to the existing magnetic field. The last 4.5 million years include four magnetic epochs (chrons) from old to young: the
Gilbert reversed, the Gauss normal, the Matuyama reversed, and the (presentday) Brunhes normal epoch. ~stratigraphic hierarchy, magnetic polarity and magnetic
(earth) field.
magnetotaxis orientation of organisms possessing magnetic crystals (some bacteria, dolphins, some birds) in the magnetic (earth) field.
Malacostraca class of the subphylum Crustacea (phylum Arthropoda), containing
most of the Crustacea including woodlice, sandhoppers, crabs, shrimps, and
lobsters. For general description of body structure ~Crustacea. The body of
the Malacostraca has basically 19 segments of which five compose the head,
eight segments form the thorax (sometimes covered by the carapace), and the
remaining six form the abdomen with telson. The segments each bear one
pair of appendages. On the head are two pairs of antennae and a pair of
stalked eyes. In the more primitive forms, all thoracic appendages are similar and used as walking legs; in others the first one, two or three pairs are
changed into maxillipeds. The abdominal appendages are smaller, and adapt-