radiolaria - Marum

Radiolaria 14 Bibliography - 1994
the lower Eo-Triassic Induan strata are missing both in the shelf and
oceanic facies. The latest Triassic "Rhaetian" is probably lacking in
the shelf facies, but developed in the oceanic facies. The shelf
facies faunas are related to those of Primorye and Siberia. On the
contrary, those of the oceanic facies have typical Tethyan aspects.
It is worthy of note that the land plants belong to the Dictyophyllum-
Clathropteris floristic province of warm climate. The present
distribution of the two quite different assemblages is well explained
by the plate tectonics theory.
O'Dogherty, L. 1994. Middle Cretaceous Radiolaria
Biochronology and Paleontology from Umbria Apennines
(central Italy) and Betic Cordillera (Spain). Ph. D. Thesis.
University of Lausanne, 375 p. (unpublished)
A highly diversified radiolarian fauna of middle Cretaceous age
has been recovered from a detailed study of pelagic and hemipelagic
sequences recording the Barremian-Turonian interval in
Mediterranean Regions. Several lithologies (limestones, cherty
limestones, marls and siliceous shales) in strata of selected
sections with long-term sedimentary continuous succession of deepsea
facies, at different localities in the Central Apennines (Apulian
Block) and on the External Zones of the Betic Cordillera (Southern
Iberian Paleomargin) were thoroughly examined.
The taxonomy and biochronology of the middle Cretaceous
Radiolaria has been studied so as to construct a precise radiolarian
zonation in the Western Mediterranean on the basis of their vertical
distribution. The sequence of species in the fossil record inevitably
reflects the order in which they evolved. Subsequently, this detailed
biochronological analysis was used for tracing evolutionary lineages
to elucidate the phylogenetic relationships of some examined taxa.
Finally, generic and suprageneric classifications have been based on
previous work as well as on my own analysis of the faunal
succession.
The biochronology has been carried out by means of Unitary
Association Method (Guex 1977, 1991). A database recording the
appearance of 303 species in 29 superposed horizons selected
from six hundred samples of seven sections has been used to
establish a sequence of 21 Unitary Associations. Each of these
associations is defined by the totality of its species pair
characteristics. The biochronological analysis has allowed the
definition of nine new radiolarian biochronologic units for the middle
Cretaceous, each assemblage are labelled either as zones or
subzones. These biochronologic units are tied to chronostratigraphy
through other coexisting fossil groups, like planktonic Foraminifera
and calcareous nannofossils previously studied by other authors at
the same localities.
Two major drastic radiolarian faunal changes coincide with well
established major Cretaceous oceanic anoxic events (OAE): early
- 107 -
Aptian to early Albian (OAE lA- OAE lB) and Cenomanian-Turonian
boundary (OAE 2).
All radiolarian species used in the biochronology have been
described with complete synonymies. They have likewise been
illustrated in order to clear up the variations of their faunal spectra .
Three families, 17 genera and 84 species are described as being
new.
Okamoto, S., Kojima, S., Suparka, S. &
Supriyanto, J. 1994. Campanian (upper Cretaceous)
radiolarian from a shale clast in the Paleogene of central Java,
Indonesia. J. Southeast Asian Earth Sc., 9/1-2, 45-50.
A Campanian (upper Cretaceous) radiolarian assemblage
containing two new species is described from a reddish brown shale
clast in a Paleogene breccia formation in the Karangsambung area,
central Java, Indonesia. The occurrence of some species typically
found in low paleolatitudes strongly suggests that the radiolarians
were deposited in a tropical ocean. On the other hand, coeval
Campanian radiolarian assemblages from the blocks in the Luk-Ulo
melanges, which unconformably underlies the Paleogene breccia
formation, are lacking in the "tropical species" obtained from the
clast in the Tertiary cover. The faunal difference indicates that the
Campanian Radiolaria-bearing siliceous rocks in the Luk-Ulo
melanges and Paleogene formation were deposited in different
paleolatitudes and juxtaposed before the deposition of the Paleogene
rocks.
Wakita, K., Munasri & Bambang, W. 1994.
Cretaceous radiolarians from the Luk Ulo Melange Complex
in the Karangsambung area, central Java, Indonesia. J.
Southeast Asian Earth Sc., 9/1-2, 29-43.
The Luk-Ulo Melange Complex is a chaotic mixture of various
kinds of sedimentary, igneous and metamorphic rocks, and is
unconformably overlain by the Eocene Karangsambung Formation.
Cretaceous radiolarians were extracted from shale and chert which
are main constituents of the complex in the Karangsambung area,
central Java. They are grouped into five assemblages (I-V). From the
radiolarian data, the siliceous and argillaceous rocks of the Luk-Ulo
Melange Complex are considered to have been deposited in Early to
Late Cretaceous time, and accreted at a subduction trench during
middle to latest Cretaceous or earliest Paleocene. As the complex is
unconformably overlain by the Eocene, the fragmentation and mixing
of these rocks with schist and quartz porphyry must have occurred
during Paleocene time.