radiolaria - Marum

Radiolaria 14 Bibliography - 1992
Sites 759 through 764 were drilled during Ocean Drilling
Program Leg 122 on the Exmouth and Wombat plateaus off
northwest Australia, eastern Indian Ocean. Radiolarian recovery was
generally poor due to unsuitable lithofacies. A few Quaternary
radiolarian faunas were recovered from most of the sites. Rare and
poorly preserved Oligocene and Eocene radiolarian faunas were
recovered from Holes 760A, 761B, 761C, and 762B. Poorly
preserved Cretaceous radiolarians occur in samples from Holes
761B, 762C, 763B, and 763C. Chert intervals from Cores 122-
761B-28X, 122-761C-5R, and 122-761C-6R contain moderately
well-preserved Cretaceous radiolarian faunas (upper Albian, mid- to
upper Cenomanian, and mid-Albian, respectively). Rare fragments of
Upper Triassic radiolarians were recovered from sections in Holes
759B, 760B, and 764A.
The only well-preserved pre-Quaternary radiolarians are in
lower and upper Paleocene faunas (Bekoma campechensis Zone)
recovered from Site 761, Sections 122-761B-16X-1 to 122-761C-
19X-CC. The composition of these faunas differs somewhat from
that of isolated coeval Paleocene faunas from Deep Sea Drilling
Project sites in the Atlantic, Gulf of Mexico, tropical Pacific, eastern
Indian Ocean, and near Spain and North Africa, as well as from
several on-land sites in North America, Cuba, and the USSR.
Blome, C.D. & Reed, K.M. 1992. Permian and Early (?)
Triassic radiolarian faunas from the Grindstone Terrane,
central Oregon. J. Paleont., 66/3, 351-383.
Moderately well preserved Permian (late Wolfcampian,
Leonardian, Guadalupian, and Djulfian) and Early(?) Triassic
radiolarian faunas from sedimentary melange cherts of the
Grindstone terrane in central Oregon are nearly identical to coeval
chert faunas in Japan. These Permian faunas are similar to those
used in constructing the radiolarian zonations for Japan and the
Tethyan regions. Although several Oregon taxa have been reported
from limestone sequences in the central United States. most of the
Oregon forms have only been found in cherty rocks and nearly half
have not previously been reported from North America. Forty-two
taxa belonging to 19 genera (Albaillella Deflandre, Deflandrella De
Wever and Caridroit, Entactinia Foreman, Entactinosphaera Foreman,
Follicucullus Ormiston and Babcock, Haplentactinia Foreman,
Hegleria Nazarov and Ormiston, Ishigaum De Wever and Caridroit,
Kashiwara Sashida and Tonishi, Latentibifistula Nazarov and
Ormiston, Latentifistula Nazarov and Ormiston, Nazarovella De
Wever and Caridroit, Neoalbaillella Takemura and Nakaseko,
Parentactinia Dumitrica, Praedeflandrella Kozur and Mostler,
Pseudoalbaillella Holdsworth and Jones, Pseudotormentus De Wever
and Caridroit, Quinqueremis Nazarov and Ormiston, and
Triplanospongos Sashida and Tonishi) are systematically treated.
Co-occurrences of some species in Oregon indicate that their ranges
in North America may differ from those in Japan. This paper also
contains the first illustrated record of Early(?) Triassic radiolarians
from North America.
Boltovskoy, D. 1992. Current and productivity patterns
in the equatorial Pacific across the last glacial maximum
based on radiolarian east-west and downcore faunal gradients.
Micropaleontology, 38/4, 397-413.
Radiolarians were studied in 11 box-cores (142 samples in
total, obtained at 3cm intervals) retrieved in the western (160°E),
central ( I 35°W) and eastern (90°W) equatorial Pacific. The western
and central cores span the last ca. 40,000 years, while the eastern
core is estimated to reach approx. 12,000-17,000 years. Timeaveraged
data show very sharp assemblage composition differences
between the three locales. Species dominant at the westernmost
sites are indicative of warm, oligotrophic conditions;
thanatocoenoses from 135°W suggest strong input of California
Current radiolarians; while the easternmost core hosts assemblages
which point to a significant influence of the Peru Current. Downcore
changes in the proportions of these three characteristic groups of
species are inconclusive in the westernmost cores. In the central
area the steady upcore increase in shells presumably advected from
the northeastern Pacific, and the concomitant decrease of warmerwater
radiolarians, indicate a growing influence of advection from
the California Current. In the easternmost core colder-water
indicators decrease from bottom to top, while those indicative of
warmer waters increase, suggesting a gradual waning of advection
from the Peru Current. It is concluded that, in the central and
eastern parts of the equatorial Pacific belt, radiolarian distributional
patterns in the sediments and their shifts during the last millennia
respond chiefly to environmental conditions at depths in excess of
50m (rather than to sea surface temperature), and to subsurface
and deep lateral advection of shells from eastern boundary current
areas.
Boltovskoy, D. & Alder, V.A. 1992a. Paleoecological
implications of radiolarian distribution and standing stocks
versus accumulation rates in the Weddell Sea. In: The
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Antarctic Paleoenvironment: A Perspective on Global
Change. (Kennett, J.P. & Warnke, D.A., Eds.), Antarctic
Research Series vol. 56. American Geophysical Union, pp.
377-384.
In the Scotia and Weddell Seas polycystine radiolarians dwell
chiefly at depths between 200 and 300 m, their vertical patterns
being strongly associated with the higher temperatures
characteristic of the Warm Deep Water. At scales of approximately
400 to 2000 km and ca. 30 days, radiolarian horizontal quantitative
distribution trends are not visibly affected by ice cover or primary
production. On the other hand, comparison of polycystine standing
stocks at 0-400 m vs. their accumulation rates at 400 to 900 m
indicates that >90% of the shells are lost to sedimentation. It is
suggested that mechanical fragmentation by grazing (rather than
dissolution) is primarily responsible for this loss. Deep habitat and
high destruction rates in the water-column are important factors
which hinder the use of Antarctic polycystine thanatocoenoses for
paleoecological reconstructions.
Boltovskoy, D. & Alder, V.A. 1992b.
Microzooplankton and tintinnid species-specific assemblage
structures: patterns of distribution and year-to-year variation
in the Weddell Sea (Antarctica). J. Plankton Res., 14, 1405-
1423.
Silicoflagellates, large heterotrophic dinoflagellates,
radiolarians, tintinnids and microcrustaceans were counted in 72
screened (15 µm) samples retrieved at 0-150 m from the Weddell
Sea in January 1989. Tintinnid species were identified and biomass
estimates were carried out for all groups on the basis of
measurements of cell dimensions. Dinoflagellates dominated the
microheterotrophic community at all stations and depths (65% of
overall microzooplanktonic carbon in the 0-150 m interval), followed
by the tintinnids (18%), microcrustaceans (16%) and radiolarians
(1%). All groups, with the exception of silicoflagellates, peaked
noticeably in the vicinity of the southern end of the transect (76-
77°S). Relationships between concentrations of chlorophyll a and
microzooplanktonic biomass were present, yet not altogether
consistent, but both phyto- and microzooplankton seemed to
generally respond to regional enhancements associated with the ice
edge. Comparison with similar Weddell and Weddell-Scotia data
retrieved in February-March 1987 and November 1988-December
1989, respectively, are highly coherent in terms of microplanktonic
abundances, their geographic and vertical distribution patterns, and
the specific make-up and distribution of tintinnid assemblages.
Analyses of the oral diameters of tintinnid morphotypes suggest
that the latitudinal and vertical distribution of their five dominant
taxa (which account for >90% of all individuals) is structured so as
to maximize resource partitioning.
Braun, A., Maass, R. & Schmidt-Effing, R. 1992.
Oberdevonische Radiolarien aus dem Breuschtal (Nord-
Vogesen, Elsas) und ihr regionaler und stratigraphischer
Zusammenhang. N. Jb. Geol. Paläont. Abh., 185/2, 161-
178.
A well preserved Radiolarian fauna (Uppermost Devonian, 13
species resp. forms) from a sequence of Greywackes and
Radiolarites of the Breuschtal is figured and described. The fauna is
discussed in its relation to the Devonian and Lower Carboniferous
sedimentary sequence on the basis of results of detailed field
mapping. It is possible to improve the correlation of single
tectonically isolated sequences of sedimentary rocks showing
different facies in this area.
Caridroit, M., Vachard, D. & Fontaine, H. 1992.
Datations par radiolaires (Carbonifère, Permien et Trias) en
Thailande nord-occidentale. Mise en évidence de nappes de
charriage et d'olistostromes. C.R. Acad. Sci. (Paris), Sér. II,
315/4, 515-520.
The classical Paleozoic stratigraphic column In NW Thailand
was described as a single Ordovician to Permian marine succession
(including undated radiolarites) considered to be tectonized in
Triassic time. Ages obtained from radiolarite dating (Carboniferous
to Triassic) demonstrate the existence of a separated sedimentary
basin far from detritic sources and far from the deposition area of
the Carboniferous to Triassic limestones. The present structural
imbrication of radiolarites with limestones and detritic series is
interpreted in terms of tectonic nappes with considerable shortening
and olistostrome deposits.
Catalano, R., Di Stefano, P. & Kozur, H. 1992.
New data on Permian and Triassic stratigraphy of Western
Sicily. N. Jb. Geol. Paläont. Abh., 184/1, 25-61.