radiolaria - Marum

Bibliography - 1991 Radiolaria 14
Abelmann, A. & Gersonde, R. 1991. Biosiliceous
particle flux in the Southern Ocean. Marine Chem., 35, 503-
538.
The flux of diatom valves and radiolarian shells obtained during
short-term and annual sediment trap experiments at seven localities
in the Atlantic sector of the Antarctic Ocean (in the Drake Passage,
Bransfield Strait, Powell Basin, NW and SE Weddell Sea and the Polar
Front north of Bouvet Island) is summarized and discussed. The
deployment of time-series sediment traps provided annual flux
records between 1983 and 1990. The biosiliceous particle flux is
characterized by significant seasonal and interannual variations.
Flux pulses, accounting for 70-95% of the total annual flux, occur
during austral summer, with a duration ranging between about 2 and
9 weeks. The annual values of vertical diatom and radiolarian flux
range between 0.26xl0 9 and morethan 26xl0 9 valves m -2 and
between 0.21x10 4 and 70x10 4 shells m -2 , respectively. Interannual
differences in the particle flux range over a factor of 10. Grazers
play an important role in controlling the quantity, timing and pattern
of the vertical biosiliceous particle flux.
The flux pattern of diatoms and radiolarians is similar at most
of the sites investigated and shows a close relationship between the
production of siliceous phytoplankton and proto-zooplankton. At
some sites, however, the radiolarian flux pattern indicates probably
phytoplankton production which is not documented by direct signals
in the trap record. During their transfer through the water column to
the ocean floor, the composition of the biosiliceous panicles is
altered mechanically (breakdown by grazing zooplankton) and by
dissolution, which significantly affects especially diatoms and
phaeodarians in the upper portion of the water column and at the
sediment-water interface.
Significant lateral transport of suspended biosiliceous particles
was observed in the bottom water layer in regions adjacent to shelf
areas (Bransfield Strait), and in the vicinity of topographic
elevations (Maud Rise), indicating considerable redistribution of
biogenic silica in these regions.
Aguado, R., O'Dogherty, L., Rey, J. & Vera, J.A.
1991. Turbiditas calcáreas del Cretácico al Norte de Vélez
Blanco (Zona Subbética): bioestratigrafía y génesis. Rev.
Soc. geol. España, 4/3-4, 271-304.
A stratigraphic, sedimentological and biostratigraphic study
(including foraminifers, nannoplankton and radiolarians) of the
Cretaceous rocks to the north of Velez Blanco (Internal Subbetic)
reveals considerable variations in the thickness, lithology and age of
the materials in many of the sections. The lowest lithostratigraphic
unit, the Carretero Formation (Upper Berriasian to upper Barremian),
crops out only locally and its facies are clearly pelagic, composed by
marls, marly limestones and limestones. The uppermost Barremian,
Aptian and Albian materials of the Fardes Formation are also pelagic
facies and in many places have intercalations of carbonate turbidite
deposits, oolitic turbidites and breccias, which in some sectors can
be quite thick. Notable among these turbidites is a megabed mainly
made up of variously sized fragments of middle Jurassic, shallow
marine limestones, redeposited in the basin during the uppermost
Aptian, which are up to 60 meters in thickness in places and are
interpreted as being turbidites related to a seismic event. Materials
from the Cenomanian-Turonian-Coniacian-Santonian (p.p.) have been
recognised in pelagic facies in two lithostratigraphic units, the
Capas Blancas Formation and "Upper Cretaceous carbonate breccia"
which interfinger laterally. The upper lithostratigraphic term, the
Capas Rojas Formation (Santonian/upper Maastrichtian) onlaps over
Jurassic rocks, which were previously exposed upon the sea bed, and
fossilizes the scarps of old faults. Intercalations of calcareous
turbidites appear from place to place within these lower Senonian
pelagic rocks.
The carbonate turbidites were deposited in small tectonic
basins bounded by normal faults, mainly in halfgrabens. Sedimentary
gravity flows were fed by submarine reliefs formed of both Jurassic
and Cretaceous materials and the fault scarps surrounding them.
They represent sedimentary bodies deposited releted to the
paleofaults on an apron model, sometimes relatively thin
(calcarenitic levels) and sometimes much thicker (calcareous
breccias and the megabed). The turbidites beds formed mainly, or
sometimes exclusively, of oolites coming from the destruction of the
Camarena Formation (middle Jurassic) are of particular interest;
these would have been well exposed on the sea bottom from whence
the turbidity currents and mass-gravitational flows were fed.
Aitchison, J., Hada, S. & Yoshikura, S. 1991.
Kurosegawa terrane: disrupted remmants of a low latitude
Paleozoic terrane accreted to SW Japan. J. Southeast Asian
Earth Sc., 6/2, 83-92.
The Kurosegawa terrane is an anomalous, disrupted,
predominantly Paleozoic lithotectonic assemblage of convergent
1991
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continental margin affinity locaied between two Mesozoic terranes in
SW Japan. On the basis of Silurian macrofossils in limestones and
sparse Devonian plant fossils in overlying volcaniclastic sediments
portions of the terrane were considered previously to represent a
Silurian through Devonian sedimentary succession. Radiolarian data,
together with sedimentological analysis, indicate the possibility that
hiatuses may occur in this succession although their position
remains indeterminate. Faunal, floral and paleomagnetic data
indicate low latitude development during the Paleozoic, probably near
the northern margins of Gondwana. Late Paleozoic oceanic crustal
rocks are incorporated in a chaotic complex which crops out along
the northern margin of the terrane. The chaotic rocks are interpreted
to represent remnants of a subduction complex. Spatial relations of
weakly-metamorphosed subduction complex rocks distributed along
the northern side of the terrane and higher grade blueschist-bearing
rocks to the south may indicate that during the Late Paleozoic to
Early Mesozoic, subduction was south-directed along the northern
margin of the Kurosegawa terrane. In the Jurassic, the Kurosegawa
terrane underwent an oblique collision with Japan which was then part
of Eurasia. Strike-slip faulting, associated with, and post-dating this
collision resulted in dispersal of the Kurosegawa terrane into a
narrow, discontinuous belt which transects the outer zone of SW
Japan.
Alder, V.A. & Boltovskoy, D. 1991. Microplanktonic
distributional patterns west of the Antarctic Peninsula, with
special emphasis on the tintinnids. Polar Biol., 11/2, 103-
112.
Microplankton was sampled with a centrifugal suction pump in
the surface layer (approx. 9 m) of the Bellingshausen Sea and the
Bransfield Strait in March 1987, and concentrated with a 26 µmmesh
net. Bulk microplanktonic settling volumes were assessed
silicoflagellates and large thecate dinoflagellates were counted, and
tintinnids were counted and identified to species. Average (and
maximum) values for the entire area surveyed were as follows,
settling volume: 6.7 (43.3) ml/m 3 ; silicoflagellates: 674 (7777)
ind./l, 0.57 (6.54) mg C/m 3 , dinoflagellates: 109 (1321) ind./l,
1.40 (16.98) mg C/m 3 ; tintinnids: 52 (589) ind./l, 1.15 (9.87) mg
C/m 3 . The three geographic zones defined objectively on the basis
of tintinnid specific assemblagcs also differed sharply in their
surface salinity, overall microplanktonic abundance and bulk settling
volume. The Bransfield Strait, with lowest settling volume values
(2.1 ml/m3) and cell concentrations, was characterized by the
dominance of Cymalocylis affinis/convallaria. In waters around the
tip of the Antarctic Peninsula microplanktonic settling volumes
averaged 4.6 ml/m 3 , cell concentrations were intermediate, and
79% of the tintinnids were represented by Codonellopsis balechi.
The Bellingshausen Sea was characterized by the lowest salinities
and the highest settling volumes (8.7 ml/m 3 ) and cell counts;
Laackmanniella spp. and Cymalocylis drygalskii, f. typica dominated
this area. Almost all biological variables were significantly
intercorrelated, and showed strong and mostly significant negative
correlations with surface salinity, yet relationships between
enhanced standing stock and ice melt water were not obvious;
rather, highest microplanktonic concentrations seemed to be due to
ice-associated growth. Extremely high spatial correlations were
found between the tintinnids and the dinoflagellates (r 2 : 0.941),
suggesting the existence of close links between these two groups.
Tintinnid species-specific assemblages show a coherent
distributional pattern and well defined environment-related trends;
most clearly diferentiated preferences are exhibited by
Laackmanniella prolongata (closely associated with ice-covered
areas), Cymalocylis affinis/convallaria (oligotrophic open-ocean
waters), and Codonellopsis balechi (coastal regions).
Amon, E.O. 1991. The correlation of polyfacial Coniacian
deposits of Urals using foraminifers. In: Paleontology and
correlation of polyprovincial and polyfacial deposits.
Reports of 38th Session of All-Union Paleontologic
Society, Novosibirik, 1992, Siberian Branch USSR Acad.
Sci. Publ., pp. 8-10. (in Russian)
Ando, H., Tsukamoto, H. & Saito, M. 1991.
Permian radiolarians in the Mt Kinkazan Area, Gifu City,
Central Japan. Bull. Mizunami Fossil Mus., 18, 101-106. (in
Japanese)
Middle and late Permian radiolarians occur in the "Toishi-type"
shale and massive black shale that crop out in the Mt. Kinkazan
area, Gifu City, central Japan. The radiolarians of the genus
Follicucullus Ormiston and Babcock are most abundant, and F
scholasticus morphotype II is the most common species. In some
samples, F scholasticus morphotype II coexists with
Pseudoaibaillella globosa,: Albaillella cf. Ievis and A. cf. excelsa The
origin of this puzzling mixture is discussed.