Geology Reference
In-Depth Information
Fig. 10.30.
Calpionellid limestone.
The pelagic limestone displays numerous cross sections and some longitudinal sections.
Only a small number of the latter shows the diagnostic criteria necessary for taxonomic assignments. The thin section yields
three species:
Calpionella alpina
Lorenz (C; see Pl. 77/6, 7),
Crassicollaria parvula
Remane (CR; Pl. 77/4), and
Remaniella
sp. (R). The assemblage indicates the
Calpionella
zone, more specifically the
elliptica
subzone (D2 interval) of the global
standard calpionellid biozonation (see Fig. 10.32). Early Cretaceous (Berriasian): Alpe Ra Stua near Cortina d'Ampezzo,
northern Italy. Courtesy of J. Blau (Giessen).
Radiolarien- und Schwammspicula-führenden Ge-
steinen der Strubbergschichten (Jura, Nördliche Kalk-
alpen, Österreich). - Neues Jahrbuch für Geologie und
Paläontologie, Monatshefte,
1983,
129-140
Kiessling, W. (1996): Facies characterization of Mid-Me-
sozoic deep-water sediments by quantitative analysis
of siliceous microfaunas. - Facies,
35
, 237-274
Kling, S.A. (1978): Radiolaria. - In: Haq, B.U., Boersma,
A. (eds.): Introduction to marine micropaleontology. -
203-244, Elsevier (New York)
O'Dogherty, L., Martin-Algarra, A., Gursky, H.J., Aguado,
R. (2001): The Middle Jurassic radiolarites and pelagic
limestones of the Nieves Unit (Rondaide Complex,
Betic Cordilleres): basin starvation in a rifted marginal
slope of the western Tethys. - International Journal of
Earth Sciences,
90
, 831-846
Racki, G., Cordey, F. (2000): Radiolarian palaeoecology
and radiolarites: is the present the key to the past? -
Earth-Science Review,
52
, 83-120
Further reading:
K112
10.2.2.3 Calpionellids
Calpionellids are extinct, bell-shaped very small cal-
citic microfossils (length about 50-200
m) that occur
abundantly in fine-grained, pelagic limestones of Late
Jurassic and Early Cretaceous Tethyan oceans. The
group suffered a dramatic decline within the Early Cre-
taceous age. The planktonic fossils are considered as a
group of the subphylum Ciliophora and the class Cili-
ata. Ciliates are distinguished from other protozoans in
having numerous tiny flagella (cilia) serving both for
locomotion and food gathering.
Calpionellids are regarded as a group of unknown
systematic position (Remane 1978), or, more com-
monly, they are attributed to the Tintinnida with which
they have strong morphological similarities and simi-
lar sizes, but differ in the material used for building the
tests. Modern tintinnids are an important component
of the microscopic zooplankton living predominantly
in the photic zone of the oceans, but also occur with
few taxa in estuaries and lakes. The bell-shaped cells
Fig. 10.31
.
Longitudinal sections and reconstructed morphol-
ogy of calpionellids.
Diagnostic criteria are the morphology
of the collar, the type of the aboral pole, and the shape and
dimensions of the test. After Brasier (1980).
