Geology Reference
In-Depth Information
Plate 67 Carboniferous and Permian Smaller Foraminifera
Late Paleozoic foraminifera shown on this plate comprise both 'smaller foraminifera' with approximately 0.1
and 0.6 mm tests, and millimeter- to centimeter-sized 'larger foraminifera' (see Pl. 68). Foraminiferal assem-
blages enable biostratigraphic zonations of Late Paleozoic, particularly Early Carboniferous ramps and plat-
forms (-> 1; Pl. 108/2) and Permian shelf deposits to be biostratigraphically zoned.
Distribution of taxa, frequency patterns and association types of Paleozoic
smaller foraminifera are used in
differentiating the facies depositional settings of ramps and mud mounds as well as recognizing environmental
conditions (water energy, paleobathymetry and sedimentation rates). Association patterns are indicative of local
shelf habitats.
This plate displays taxa common in Carboniferous (-> 1, 6, 11) and Permian (-> 2-5, 7-10) shelf and reef
carbonates. Agglutinated foraminifera (-> 9) as well as foraminifera with calcitic microgranular (-> 1, 5, 6) or
porcelaneous walls (-> 7) are used in paleoecological analyses. Note the different growth forms, including
unilocular tests, shells consisting of a proloculus followed by a tubular non-divided chamber (-> 2), multicham-
bered uniserial (-> 4) or coiled tests (-> 11) and conical trochospiral tests (-> 1).
1
Biozonation based on smaller foraminifera.
The succession of foraminiferal assemblages permits zonation and global
correlation of Tournaisian and Viséan ramps and platforms. The sample shows a foraminiferal grainstone with axial
sections of
Forschia prisca
Mikhailov (center left) and equatorial sections of
Endothyranopsis crassa
(Brady), top right,
indicating the Late Viséan foraminiferal zone 15. Early Carboniferous: Basin of Dinant, Belgium.
2
Encrusting foraminifera
and very small tubular microfossils, usually also assigned to foraminifera, are common con-
stituents of Late Paleozoic shelf carbonates. Some of these foraminifera encrusted algal blades, others hard bottoms.
Note that recrystallization only affected the matrix, but not the microgranular foraminiferal tests. Abundant taxa are
Tuberitina
Galloway and Harlton (T) belonging to the parathuramminacean Fusulinina, and
Earlandia
Plummer (E)
assigned to the earlandiacean Fusulinina. Both genera occurred in inner and outer shelf environments. The sample is
from the top of a meter-scaled cyclothem. Early Permian (Asselian): Carnic Alps, Austria.
3
Miliolinid attached foraminifera
. The initial chamber of
Apterinella
Cushman and Waters is encircled by uncoiled cham-
bers planspirally enrolled and later arranged in zigzag bends. The wall appears dark in transmitted light. The sample is
from back-reef carbonates deposited in the leeward position of a platform margin reef. Middle Permian (Capitanian):
Permian Reef Complex, Texas, U.S.A.
4
Differentiated wall structure.
The wall of
Pachyphloia/Langella
exhibits a thin dark inner layer (arrow) and a thick
hyaline outer layer. The uniserial elongate test consists of strongly overlapping chambers. Middle Permian: Pietra di
Salomone near Sosio, western Sicily.
5
Differentiated test.
Axial sections of
Lasiotrochus tatoensis
Reichel (left) and
Lasiotrochus minor
Reichel. Note initial
chamber and microgranular wall. Arrows point to hyaline pillars composed of transparent calcite and tubular chamberlets.
Genus range: Permian. Same locality as -> 4.
6
Differentiated test
. Oblique axial section of
Howchenia
Cushman. Conical test. The undivided tubular chamber is coiled
in a high spire around an umbilical region filled with fibrous calcite. The genus is restricted to Viséan to Moscovian and
common in intraclastic wackestones deposited in deep shelf environments affected by storm waves. Early Carboniferous
(Badstuben Breccia, Viséan): Nötsch, Carinthia, Austria.
7
Miliolinid foraminiferal grainstone
with
Hemigordius
Schubert. The porcelaneous discoidal tests appear dark in trans-
mitted light. The dark tint is intensified by early pyritization of the tests. The sample is from black limestones represent-
ing bioclastic shoals within a restricted lagoon. Late Permian (Bellerophon Formation, Dorashamian): Comelico, north-
ern Italy.
8
Tetrataxis
Ehrenberg, a common Carboniferous and Permian genus occurring in open-marine subtidal crinoid and bryo-
zoan thickets at or below the fair-weather wave base, which were reworked by currents and storms. The wall consists of
an outer microgranular layer and hyaline radiate inner layer.
Tetrataxis
was a loosely attached mobile foraminifer that
responded to environmental extremes by attaching onto substrates (Cossey and Mundy 1990). The test is encrusted by
Tuberitina,
(T). Genus range: Early Carboniferous to Triassic. Early Permian: Carnia, Italy.
9
Agglutinated textulariid foraminifera.
Tangential and more central longitudinal sections. The wall is composed of fine
sand grains. The chambers are uniserially arranged. Early Permian: Southern Karawanken Mountains, Austria.
10
Cribrogenerina
Schubert, a common Permian palaeotextulariid foraminifera. The genus is characterized by initially
biserial, later uniserial, broad chambers with multiple and cribrate roofs. The oblique section displays the uniserial part
of the test. Late Permian (Zazar Formation): Idrija, Slovenia.
11
Bradyina
Möller, an endothyracean fusulinid foraminifer which was common in Carboniferous shallow-marine algal
meadows. Planispiral involute test, sutures deeply incised. Calcareous wall, with microgranulate outer layer (tectum, T)
and inner perforate structure (P). Late Carboniferous (Gzhelian): Nassfeld, Carnic Alps, Austria.
-> 4, 5: Flügel et al. 1991; -> 7, 10: Noé 1987
