radiolaria - Marum

Bibliography - 1990 Radiolaria 14
Ishiga, H., Choi, J. & Sato, M. 1990. Geologic
examination of the borehole data from the eastern part of the
Himeji Prefecture, Southwest Japan. Geol. Rep. Shimane
Univ., 8, 61-71. (in Japanese)
Geologic structure and stratigraphy of the Permo-Triassic
strata of the Kozuki-Tatsuno Belt in the eastern part of the Himeji
area. Southwest Japan were examined on the basis of the borehole
data which has 1440m depth from the ground. The rock unit in this
area consists of the Permian Tatsuno Group and the unnamed
Triassic strata, and they are repeated by thrust fault. Mudstones of
the Tatsuno Group from the horizon 735m of the borehole yield
Pseudoalbaillella aidensis, P. yanaharensis, P. globosa and P. spp.
Sandstones of the Tatsuno Group are characterised by wacke
including plagioclase, rock fragments and less amount of quartz
grains, while sandstones of the Triassic formation is arenite.
characterised by large amound of quartz, K-feldspar and less
amount of rock fragments.
Although the Triassic formation is not distributed on the ground
surface, the borehole data reveals that the strata correlative to the
Hiraki Formation is widely distributed in the Kozuki-Tatsuno Belt. The
granitic rocks appears just beside to the east of the examined area,
and this granites occurs in the 1200m depth. Thus, the fault with
NE-SW direction cut the strata and the block of the ground greatly
upheaved about 900m judging from the difference of the horizons of
contact between granitic intrusion and the sediments in each block.
Ishii, A., Takahashi, O. & Hayashi, N. 1990.
Geology of the Kawakami-Sudama area, western part of the
Kanto Mountains, central Japan. Bull. Tokyo Gakugei Univ.
Sect. 4, 42, 171-181. (in Japanese)
Iwata, K., Hariya, Y., Choi, J.H., Yagi, E. &
Miura, T. 1990. Radiolarian age of the manganese deposits
of the tokoro belt, northeast Hokkaido. J. Fac. Sci. Hokkaido
Univ., 22/4, 565-576.
Radiolarian fossils of early Cretaceous (middle Barremian-early
Aptian) were obtained from the country rock (bedded red chert) of
the manganese deposit of the Hinode mine in the Tokoro Belt. By this
discovery of radiolarians the geological age of the formation of the
manganese deposit of the Hinode mine was determined for the first
time to be formed during a short period of ca. 110-120 Ma.
Radiolarian fossils of early Cretaceous in age were also extracted
from bedded cherts of the Wakasa, Koryu, Syotosibetu, and
Hokkaido mines which were similar manganese deposits to the
Hinode mine. This fact suggests that manganese deposits in the
Tokoro Belt were formed almost simultaneously during late early
Cretaceous time.
Jauhari, P. 1990. Relationship between morphology and
composition of manganese nodules from the central Indian
Ocean. Marine Geol., 92/1-2, 115-125.
Spheroidal nodules having a diameter between 2 and 4 cm and
surface textures ranging from smooth to coarsely granular or of
intermediate nature are the most common. The nodule facies and
their compositions are influenced by the underlying sediment
through which they receive some of their constituents. The
association of coarse texture with the siliceous sediments reflects
the precipitation of larger particles of manganese oxides through the
larger pore spaces of the sediment as a result of the enhanced early
diagenetic effects. The smooth texture, in contrast, reflects the
direct supply of manganese oxides from the overlying bottom water
as a result of their precipitation as authigenic oxyhydroxides.
Johnson, D.A. 1990. Radiolarian biostratigraphy in the
central Indian Ocean, Leg 115. In: Proceedings of the Ocean
Drilling Program, Scientific Results. (Duncan, R.A.,
Backman, J., Peterson, L.C. et al., Eds.), vol. 115. College
Station, TX (Ocean Drilling Program), pp. 395-409.
Identifiable radiolarians of stratigraphic importance were
recovered at eight of the sites drilled on Leg 115. The assemblages
range in age from Holocene to middle Eocene (Dictyoprora
mongolfieri Zone, about 48 Ma). Faunal preservation is particularly
good in two stratigraphic intervals: the Holocene through upper
Miocene (0-9 Ma), and the lowermost Oligocene to middle Eocene
(35-48 Ma). Fluctuating rates of silica accumulation at these drill
sites during the Cenozoic reflect changing tectonic and
paleoceanographic conditions. In particular, the gradual closure of
the Indonesian and Tethyan seaways and the northward migration of
the Indian subcontinent severely restricted zonal circulation and
silica accumulation in tropical latitudes during the late Oligocene
through middle Miocene. By the late Miocene the Indian subcontinent
had moved sufficiently north of the equator to allow trans-Indian
zonal circulation patterns to become re-established, and biosiliceous
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sedimentation resumed. The composition of the radiolarian
assemblages in the tropical Indian Ocean is closely comparable with
that of the "stratotype" sequences in the equatorial Pacific.
However, there are some notable exceptions in Indian Ocean
assemblages: (I) the scarcity of the genera Pterocanium and
Spongaster in the Neogene; (2) the absence of the stratigraphically
important Podocyrtis lineage, P. diamesa ⇒ P. phyxis ⇒ P. ampla, in
the middle Eocene; and (3) the scarcity of taxa of the genus
Dorcadospyris, with the exception of D. ateuchus. The succession of
radiolarian events was tabulated for those stratigraphic intervals
where the assemblages were well preserved. We identified 55
events in the middle Eocene to earliest Oligocene and 31 events in
the late Miocene to Holocene. The succession of events is closely
comparable with that of the tropical Pacific. However, there are
exceptions that appear to be real, rather than artifacts of sample
preservation, mixing, and core disturbance.
Khokhlova, I.Y. 1990. The Neogene stratigraphy of the
temperate and south-borealic Pacific Radiolaria. Izv. Akad.
Nauk SSSR, ser. geol., 1, 18-28. (in Russian)
Neogene deposits, discovered in the northern part of the Pacific
ocean by wells 578, 580 and 581 of the DSDP, were divided in
accordance with the zonal scale on the basis of radiolaria, and
correlated. The zonal complexes of radiolaria from the temperate
and southern boreal N zones of the Pacific ocean were described.
They were compared with each other and with coeval tropical
complexes. The zones based on Radiolaria were compared with
palaeomagnetic data about the same wells. The positions of the
boundaries of identical zones in the tropics and the temperate zone
were found to be different.
Kiminami, K., Kawabata, K. & Miyashita, S.
1990. Discovery of Paleogene radiolarians from the Hidaka
Supergroup and its significance with special reference to ridge
subduction. J. geol. Soc. Japan, 96/4, 323-326. (in
Japanese)
The Mesozoic rocks of the Hidaka Belt distributed on the
central part of Hokkaido, Japan are made up the Hidaka Supergroup.
The Hidaka Supergroup is composed mainly of turbidite and melange,
and is considered to be accretionary body formed by west ward
subduction of Cretaceous in time. The accretionary body are divided
into two parts, they are western margin area and eastern area by
radiolarian fossils. The former is early Cretaceous and latter is
considered to be late Cretaceous, approximately Campanian in age.
The westward subduction formed the Hidaka Belt are also thought to
be finished till late Cretaceous on the basis of these radiolarian
ages. In this paper, we reported the discovery of Paleogene (approx.
middle to late Eocene) radiolarian fossils from the eastern margin of
the Hidaka Belt and discussed its significance.
Kito, N. & De Wever, P. 1990. Analyse cladistique de la
phylogenie des Hagiastridae (Radiolaires Mésozoïques). Rev.
Micropaléont., 33/3-4, 193-218.
An analysis of the relationships of the Hagiastridae has been
undertaken with the parcimony method in order to compare these
results with previous propositions. The study has been carried out
with 16 characters. 19 taxa are clustered within two subfamilies:
Archaeohagiastrinae and Hagiastrinae, the later being subdivided
into three tribes. The resulting phylogenetic tree situated in its
stratigraphic frame, reveals two main periods of diversification: one
during the Hettangian and one about the Toarcian.
Kito, N., De Wever, P., Danelian, T. & Cordey,
F. 1990. Middle to Late Jurassic radiolarians from Sicily
(Italy). Mar. Micropaleontol., 15/3-4, 329-349.
Middle and Upper Jurassic radiolarian faunas from two sections
of Sicily are compared with the previously proposed zonations. The
ages of the faunas are estimated by correlation with these zonations
and by concurrent range zone. The faunas could be assigned to the
Bathonian or earlier late Tithonian or early Berriasian. Two new
spumellarian species (Bernoullius furcospinus and Bernoullius
rectispinus) from Middle Jurassic are described.
Koutsoukos, E.A.M. & Hart, M.B. 1990.
Radiolarians and Diatoms from the mid-Cretaceous
successions of the Sergipe Basin, northesatern Brazil:
palaeoceanographic assessment. J. Micropaleont., 9/1, 45-
64.
Radiolarians and diatoms are documented for the first time
from the mid- Cretaceous succession of the Sergipe Basin, a passive
marginal basin in northeastern Brazil. Prevailing palaeoceanographic
conditions are inferred for the episodes of siliceous radiolarian and
diatom biomineralization/preservation. Radiolarian faunas are first