radiolaria - Marum

Radiolaria 14 Bibliography - 1990
Sharma, V. & Mahapatra, A.K. 1990. Radiolarian
occurrences in surface sediments of the Indian Ocean in
relation to bottom water circulation. J. geol. Soc. India,
35/3, 251-261.
Occurrences of Radiolaria in the surface sediments collected at
22 stations in the Indian Ocean are noted. While some samples
contain abundant Radiolaria, others show extremely poor
concentration, or, are practically devoid of them. A distinct
relationship is found between radiolarian abundance and deep water
current systems. It is suggested that the occurrence of Radiolaria is
largely controlled by currents which are responsible for dissolving
radiolarian skeletons. The assemblage is dominated by warm-water
species and also contains a few cold water forms. The cold-water
species are believed to be transported by the Antarctic Bottom
Waters (AABW) to the present area.
Skornyakova, N.S., Uspenskaya, T.Y.,
Gorshkov, A.I. & Sivtsov, A.V. 1990. Ironmanganese
concretions from the central trough of the Indian
Ocean. Izv. Akad. Nauk SSSR, ser. geol., 6, 117-120. (in
Russian)
Examines the internal structure, chemical and mineral
composition of concretions from the radiolarian zone. Local
variations in the concretions were noted. Sedimentational and
diagenetic concretions were compared, and the conditions governing
their formation were described.
Smith, P.L. & Carter, E.S. 1990. Jurassic correlations
in the Iskut River map area, British Columbia, and the age of
the Eskay Creek deposit. Geol. Surv. Canada, curr. res., Pap.,
90-1E, 149-151.
A high-resolution, Jurassic biochronology based on macro- and
microfossils could have important applications in the tectonically
complex Iskut map area where Jurassic sediments accumulated in a
shallow marine, volcanically active area characterized by rapid
lateral variations in facies. Reconnaissance work in the upper
drainage of the Unuk River has produced Pliensbachian to possibly
Oxfordian age ammonite and radiolarian faunas, some of which are
anomalous with respect to currently available geological maps. The
presence of Jurassic radiolarians in well-rounded clasts of Jurassic
conglomerates may offer the opportunity of constraining periods of
Jurassic tectonism. Upper Pliensbachian ammonites were collected
stratigraphically below the Eskay Creek deposit. A limestone clast
from a conglomerate above the deposit has yielded radiolarians that
indicate a Middle Toarcian to Early Bajocian age.
Spindler, M. & Beyer, K. 1990. Distribution,
abundance and diversity of Antarctic acantharian cysts. Mar.
Micropaleontol., 15/3-4, 209-218.
Large numbers of acantharian cysts, up to more than 30
individuals per m 3 , were collected during the austral summer
(January-February) 1985 in the Weddell Sea, Antarctica by a
multiple open-closing plankton net system. Stations were sampled
17 days later in the season and revealed slightly higher abundances
of cysts. Samples collected in the same region during winter and
spring 1986 (July-November) contained no acantharian cysts. The
numbers of cysts decreased from open ocean conditions to locations
close to the ice shelf coast. Cysts were most abundant in water
depths between 100 and 300 meters. The morphology of the cysts,
constructed from differently shaped strontium sulfate plates or
from amorphous strontium sulfate, is described and the taxonomy of
the different types discussed.
Stais, A., Ferriere, J., Caridroit, M., De Wever,
P., Clement, B. & Bertrand, J. 1990. Données
nouvelles sur l'histoire ante-obduction (Trias-Jurassique) du
domaine d'Almopias (Macédoine, Grèce). C.R. Acad. Sci.
(Paris), Sér. II, 310/11, 1457-1480.
Chert beds from Almopias area have been dated with radiolarian
remains: some of them never described before. are Triassic (Vrissi
Unit) while others, chert and volcanic beds from Mavrolakkos Unit
are Jurassic early neocomian (probably Upper Jurassic). These
results give some information on the unknown geological history of
this area during Triassic-Jurassic times. They support the
hypothesis of the existence of a Jurassic oceanic crust basin east of
the Pelagonian zone, initiated during Triassic times. Finally, they
modify the data used to discuss the existence of an Upper
Cretaceous oceanic crust in the Alnlopias area.
Swanberg, N.R., Anderson, O.R. & Bennett, P.
1990. Skeletal and cytoplasmic variability of large
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spongiose spumellarian radiolaria (Actinopodea:
Polycystina). Micropaleontology, 36/4, 379-387.
Large, spongiose skeletal Radiolaria occur abundantly in
tropical and some subtropical oceanic locations. They are
particularly conspicuous in plankton tows owing to their brightly
coloured central capsular region (red to purplish-brown) and the
numerous dinoflagellate, prymnesiophyte, or prasinophyte symbionts
that impart a distinctly golden-brown or greenish hue to the
peripheral cytoplasm. There is substantial variability in skeletal and
cytoplasmic morphology and the major skeletal features used by
Haeckel and others to discriminate among species intergrade to
such a degree that it is not possible in most circumstances to make
a clear taxonomic distinction. Furthermore, there is no correlation
between the kind of symbiont associated with the host and its
skeletal organization. Moreover, there is a nearly continuous
variation in cytoplasmic organization of the central capsules varying
from loosely organized radially arranged lobes surrounding a
centrally located nucleus to a more spongiose and compact
cytoplasm (consisting of interconnected masses of nucleated
cytoplasm) with large, densely staining reserve bodies. In the
extreme development of spongiose cytoplasmic organization, the
reserve substance is dispersed throughout the cytoplasm. There is
no correlation between the degree of spongiose quality of the
cytoplasm and the organization of the skeleton. The variations in
cytoplasmic organization suggest an ontogenetic sequence
progressing from a large, centrally located nucleus with loose,
radially-arranged cytoplasmic lobes toward increasingly dispersed
nuclear lobes distributed into the peripheral cytoplasm containing
abundant reserve bodies. Further research is needed to evaluate this
hypothesis. In overall perspective, the variability among this group is
so large and so intergraded that due caution is advised in assigning
them to different species. Indeed, given the lack of clear skeletal
and cytoplasmic demarcation within this group, and the absence of
molecular genetic information to clarify the species affinities, it may
be misleading to establish species based only on skeletal evidence.
Moreover, further research is required to determine how much of the
variation in skeletal structure can be attributed to genetic
differences (taxonomic differences) versus ecophenotypic variation
that may provide information about environmental variables
recorded in the skeletal morphology.
Tajika, J. & Iwata, K. 1990. Paleogene melange of the
northern Hidaka Belt - Geology and radiolarian age of the
Kamiokoppe Formation. Mem. Hokkai Gakuen Univ., 66,
35-55. (in Japanese)
Geological and paleontogical investigation of the Hidaka
Supergroup (Kamiokoppe Formation) in the Nishiokoppe area,
northeast Hokkaido was carried out to examine sedimentary
environment and to decide the age of the Hidaka Supergroup. The
Kamiokoppe Formation consists of pillow basalt, red mudstone, and
overlying repetitions of coarsening upward sequence of sandstone
and mudstone. This formation includes a sedimentary melange called
Honmanosawa melange, in which exotic olistoliths of limestone and
chert are characteristically included. Paleocene radiolarians were
extracted from the red mudstone of the Kamiokoppe Formation. This
age may suggest the age of accumulation of the Kamiokoppe
Formation. Triassic holothurian sclerites and radiolarians were
discovered from blocks of limestone and chert in the Honmanosawa
melange, and late Cretaceous radiolarians were also found from
black mudstone of the same area, but matrix of this melange did not
yet occur microfossils.
Takahashi, K. 1990. Radiolarians from the distal Bengal
Fan in the Equatorial Indian Ocean. In: Proceedings of the
Ocean Drilling Program, Scientific Results. (Cochran, J.R.,
Stow, D.A.V. et al., Eds.), vol. 116. College Station, TX
(Ocean Drilling Program), pp. 207-209.
Cores recovered from three sites of Leg 116 were studied for
radiolarians. Generally, radiolarians were absent from most samples
prepared for examination. Moderate to well-preserved radiolarian
assemblages are found only in the uppermost one or two cores that
were the focus of this study. All of the radiolarian assemblages in
the upper cores belong to the Buccinosphaera invaginata Zone of
latest Quaternary age. However, there is one stratum where a few
Miocene radiolarians are reworked into the modern assemblages.
Local seamounts are suggested sources for the reworked
radiolarians.
Takahashi, K., Billings, J.D. & Morgan, J.K.
1990. Oceanic province: assessment from time-series diatom
fluxes in the northeastern Pacific. Limnol. and Oceanogr.,
35/1, 154-165.
Samples were recovered from time-series sediment traps
deployed simultaneously for one full year (l985-1986) at pelagic
StationsPapa and C (~600 km apart) in the northeastern Pacific.