1.5 Methods of Study
11
Spines; Erdtman (1952): Long, conspicuous and generally sharp projections.
Length exceeding 3 µ.
Striae; Faegri and Iversen (1950): Narrow grooves, more or less parallel (length
at least twice the breadth), separated by ridges.
Structure; Potonie and Kremp (1955): Elements that do not form a relief on
outer exine surface. Made up of elements present between ektexine and endexine
(internal texture).
Sulcus; Erdtman (1952): In pollen grains, a longitudinal aperture or furrow on
distal face.
Tetrad; Wodehouse (1935): Union of 4 pollen grains or spores formed by one
mother cell.
Taeniae; Jansonius (1962): In saccate pollen grains, the cappa has bands of
thickened ektexine divided by grooves.
Tetrad mark; Dettmann (1963): The mark (scar) that is left on the proximal face
of the spore, which has been in contact with the other members of the tetrad.
Verrucate; Erdtman (1952): Wart-like projections. Size over 1 µ.
Zona; Potonie and Kremp 1955: An equatorial extension of the ektexine. Differs
from the cingulum in not exceeding the thickness of the ektexine which it is part
of.
Structural and sculptural terms used when seen in optical section, and surface
view follow Erdtman (1952) as well as the illustrations and definitions of Gambarelli
et al. (1989).
1.5.3 Bodies Lacking Haptotypic Features: Acritarchs
Alete bodies without any visible haptotypic features are grouped in the present study
under Acritarcha, a term proposed by Evitt (1963) for ‘spore-like bodies of unknown
affinity, partly planktonic and probably algal in origin’.
The term ‘Acritarchs’ refers to single-celled organic microfossils present in rocks
from the Cambrian throughout geological history. The earliest in geological time are
mostly simple, namely unornamented. The Permian acritarchs range from smooth
walled to having ornamentation. They range in size from minute spheres to 100 µ and
more. The name ‘Acritarcha’ originates from Greek, meaning ‘uncertain origin’. The
name is still used although many acritarchs by now have been assigned to known
groups or taxa of aquatic plants. All fossil acritarchs show close resemblance to
aplanospores of living algae in the aquatic environment.
Most of the acritarchs described in the present study were scattered in small
numbers within various samples throughout the boreholes. However, some acritarchs
were restricted to certain stratigraphic levels (see pollen curve charts) and are of great
value as indicators of specific environmental conditions at the time. Banerjee and
D’Rozario (1990) plotted the distribution of acritarchs in the Lower Permian deposits
of eastern India and discussed their significance in interpreting the climatic conditions
11
Spines; Erdtman (1952): Long, conspicuous and generally sharp projections.
Length exceeding 3 µ.
Striae; Faegri and Iversen (1950): Narrow grooves, more or less parallel (length
at least twice the breadth), separated by ridges.
Structure; Potonie and Kremp (1955): Elements that do not form a relief on
outer exine surface. Made up of elements present between ektexine and endexine
(internal texture).
Sulcus; Erdtman (1952): In pollen grains, a longitudinal aperture or furrow on
distal face.
Tetrad; Wodehouse (1935): Union of 4 pollen grains or spores formed by one
mother cell.
Taeniae; Jansonius (1962): In saccate pollen grains, the cappa has bands of
thickened ektexine divided by grooves.
Tetrad mark; Dettmann (1963): The mark (scar) that is left on the proximal face
of the spore, which has been in contact with the other members of the tetrad.
Verrucate; Erdtman (1952): Wart-like projections. Size over 1 µ.
Zona; Potonie and Kremp 1955: An equatorial extension of the ektexine. Differs
from the cingulum in not exceeding the thickness of the ektexine which it is part
of.
Structural and sculptural terms used when seen in optical section, and surface
view follow Erdtman (1952) as well as the illustrations and definitions of Gambarelli
et al. (1989).
1.5.3 Bodies Lacking Haptotypic Features: Acritarchs
Alete bodies without any visible haptotypic features are grouped in the present study
under Acritarcha, a term proposed by Evitt (1963) for ‘spore-like bodies of unknown
affinity, partly planktonic and probably algal in origin’.
The term ‘Acritarchs’ refers to single-celled organic microfossils present in rocks
from the Cambrian throughout geological history. The earliest in geological time are
mostly simple, namely unornamented. The Permian acritarchs range from smooth
walled to having ornamentation. They range in size from minute spheres to 100 µ and
more. The name ‘Acritarcha’ originates from Greek, meaning ‘uncertain origin’. The
name is still used although many acritarchs by now have been assigned to known
groups or taxa of aquatic plants. All fossil acritarchs show close resemblance to
aplanospores of living algae in the aquatic environment.
Most of the acritarchs described in the present study were scattered in small
numbers within various samples throughout the boreholes. However, some acritarchs
were restricted to certain stratigraphic levels (see pollen curve charts) and are of great
value as indicators of specific environmental conditions at the time. Banerjee and
D’Rozario (1990) plotted the distribution of acritarchs in the Lower Permian deposits
of eastern India and discussed their significance in interpreting the climatic conditions