radiolaria - Marum

Bibliography - 1992 Radiolaria 14
The limestone-bearing clastic sequences of both subterranes are
regarded as shelf or inner-trench slope sediments deposited on the
chert clastic and olistostromal sequences.
Two major stages of tectonic development are discriminated.
The Togano subterrane was formed by successive offscrape
accretion mainly during the Middle to Late Jurassic. The Sambosan
subterrane was constructed by collision-accretion of seamounts
mainly during the Late Jurassic to Early Cretaceous. The difference
in the tectonic processes is considered to relate to topography of
subducting oceanic plate; an oceanic plate with an abyssal plain for
the Togano subterrane and an oceanic plate with seamounts for the
Sambosan subterrane.
Matsuoka, A. 1992d. Jurassic and Early Cretaceous
radiolarians from Leg 129, Sites 800 and 801, western Pacific
Ocean. In: Proceedings of the Ocean Drilling Program,
Scientific Results. (Larson, R.L., Lancelot, Y. et al., Eds.), vol. 129.
College Station, TX (Ocean Drilling Program). pp. 203-220.
Rich radiolarian faunas were obtained continuously from Middle
Jurassic to Lower Cretaceous radiolarite sequences at Sites 800
and 801, drilled during Ocean Drilling Program Leg 129 in the
western Pacific. Occurrences of 90 taxa are presented in tables for
these sites. Seven radiolarian zones, Dibolachras tytthopora,
Cecrops septemporatus, Pseudodictyomitra carpatica,
Pseudodictyomitra primitiva, Cinguloturris carpatica, Stylocapsa(?)
spiralis, and Tricolocapsa conexa in descending order, were
recognized in this interval. The radiolarite sequences of Sites 800
and 801 encompass approximately the Berriasian to Hauterivian (or
to Barremian) and the Bathonian/Callovian to Valanginian ages,
respectively. At Site 801, a hiatus of early Oxfordian was identified.
Matsuoka, A. 1992e. Observation of radiolarians and their
symbionts on discoidal spumellarida. Fossils, 53, 20-28. (in
Japanese)
Matsuoka, A. 1992f. Observation and growth record of
living radiolarians - a case study of Dictyocoryne truncatum.
Hyoseki: Tsurumatsu MANABE, memorial volume, 10, 67-
76. (in Japanese)
Matsuoka, A. & Anderson, O.R. 1992. Experimental
and observational studies of radiolarian physiological
ecology: 5. Temperature and salinity tolerance of
Dictyocoryne truncatum. Mar. Micropaleontol., 19/4, 299-
313.
The longevity and skeletal growth of Dictyocoryne truncatum,
collected from surface waters near Barbados, were assessed in
laboratory culture in relation to variations in temperature and
salinity. The range of longevities for groups of organisms collected
at different times, but maintained at 28 ° C and 35.0‰ salinity,
exhibited a wide fluctuation ( 1-2 to 5-37 days). The amount of
growth also showed a wide variation among the groups since it was
generally proportional to the longevity. The causes of the variation in
longevity and growth are not known, but we hypothesize that a
combination of genetic variability and physical and biological factors
intrinsic to the culture conditions produced the variability.
D. truncatum showed a narrow temperature range for skeletal
growth with an optimum in our culture conditions at about 28°C.
Temperatures over 32°C or under 21°C suppressed skeletal growth.
D. truncatum has a much wider temperature tolerance for survival
than for growth. Longevity at temperatures as low as 15°C was
comparable to that at 28°C. This indicates that D. truncatum can
endure periods of relatively low temperatures. This may have
survival advantage by conferring resistance to lower temperatures
at great depths in the water column or during intrusion of colder
water masses into warmer surface water regimes, but we have
presently no evidence of their reproductive capacity at these lower
temperatures. These results are consistent with a theory that D.
truncatum is largely a surface-dwelling species surviving optimally
in warmer water that supports optimum skeletal growth and
maturation. The tolerance of cooler water, however, may also reflect
biological adaptations related to variations in habitat during the
reproductive cycle. Mature organisms may sink and release
reproductive swarmers at greater depths in a water column, judging
from the observation that mature individuals in culture withdrew
their axopodia prior to swarmer release and settled to the bottom of
culture vessels. The low temperature tolerance may also permit
survival of juvenile organisms until they ascend into more warm
surface water strata.
Cultured D. truncatum has a wide growth and survival tolerance
for variations in salinity. Mean growth and longevities were
comparable at salinities of 27‰ and 35.0‰. A broad tolerance for
variations in salinity can enhance survival at locations where wide
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variations in salinity occur regularly as happens near Barbados
where the surface water is diluted by river outflows. The low salinity
tolerance is also consistent with the interpretation that D.
truncatum dwells in near-surface water in low latitude, open ocean
locations.
Mizutani, S. & Kojima, S. 1992. Mesozoic radiolarian
biostratigraphy of Japan and collage tectonics along the
eastern continental margin of Asia. In: Significance and
application of Radiolaria to terrane analysis. (Aitchison, J.C.
& Murchey, B.L., Eds.), vol. 96/1-2. Special Issue:
Palaeogeogr. Palaeoclimatol. Palaeoecol., Elsevier,
Amsterdam. pp. 3-22.
Jurassic accretionary complexes mainly composed of
Carboniferous to Permian limestone associated with greenstone,
Triassic bedded chert, Jurassic siliceous shale and clastic rocks
form the basement rocks of Japan. The stratigraphy of these
complexes has recently been analysed utilizing radiolarian fossils,
resulting in the discovery that Japan comprises a collage of
disrupted terranes. International co-operative works reveal that
lithologically and biostratigraphically similar terranes are distributed
in northeast China (Nadanhada terrane) and Sikhote-Alin, USSR
(Khabarovsk terrane). Paleomagnetic studies demonstrate that prior
to opening of the Sea of Japan the Japanese Islands were located
much closer to the eastern margin of the Asian continent where the
Nadanhada and Khaborovsk terranes are now exposed. Features of
the Mino terrane in central Japan are characteristic of these
terranes which originally formed along the continental margin of East
Asia. Seamounts covered by fossiliferous limestone formed during
the Carboniferous to Permian at low latitudes. The seamounts drifted
towards a continental margin together with upper Paleozoic
sediments, Triassic bedded chert and Lower Jurassic siliceous shale
which accumulated around them. Upper Paleozoic, Triassic and Lower
Jurassic formations were accreted to the eastern continental
margin, which was a large tectonic collage developed as the Chinese
mainland during the Late Triassic. Enormous amounts of clastic
detritus were deposited in sedimentary basins where jumbling and
telescoping of pelagic sediments took place in a complicated fashion
producing a melange. The provenance of clastic detritus within the
Mino terrane is interpreted as a platform on which Permian and
Carboniferous calcareous sediments containing diagenetic lutecite
and orthoquartzite formations were widespread. These formations
covered a Precambrian metamorphic and granodioritic basement
similar to that seen in the South China region. Accretion culminated
in the earliest Cretaceous and the large disrupted terrane which had
developed was transpressed north-wards along the eastern margin
of the continent. During this period of dispersal the original terrane
was sheared, fragmented and separated into many smaller terranes
some of which were transported to the Sikhote-Alin region by the
Late Cretaceous. The most recent dispersal occurred during the
opening of the Sea of Japan, which is closely related to the latest
movement of the Pacific plate.
Studies of radiolarian micropaleontology and the significance of
these fossils to the resolution of the biostratigraphy and the
tectonic history of Japan are reviewed. The results of
biostratigraphic analyses are discussed in relation to the Mesozoic
tectonics of East Asia.
Molinie, A.J. & Ogg, J.G. 1992. Milankovitch cycles
in Upper Jurassic-Lower Cretaceous radiolarites of the
equatorial Pacific: spectral analysis and sedimentation rate
curves. In: Proceedings of the Ocean Drilling Program,
Scientific Results. (Larsen, R.L., Lancelot, Y. et al., Eds.),
vol. 129. College Station, TX (Ocean Drilling Program), pp.
529-547.
Periodic changes in depositional environments due to
Milankovitch astronomical climate cycles can cause cyclic patterns
in sedimentation properties as recorded by logging data. Ocean
Drilling Program Site 801 recovered Callovian (upper Middle
Jurassic) through Valanginian (Lower Cretaceous) clayey
radiolarites, originally deposited in a near-equatorial setting. Cycles
of variable concentration of radiolarians and clay, and associated
changes in degree of silicification were apparent in the geophysical
logs, especially in the gamma-ray signal and the Formation
MicroScanner. Three-dimensional spectral analysis was performed
on the gamma-ray log signal using a 40-m sliding window. The
dominant spectral peaks maintain the same relative ratios in
frequency as the 413-k.y., 123-k.y., and 95-k.y. Milankovitch
periods of eccentricity. The wave lengths of these eccentricitymodulated
cycles were used to determine rates and discontinuities
in sedimentation with depth.
Two sharp discontinuities in sedimentation rate were inferred:
(1) Callovian alternations of red radiolarite and claystone, with a
sedimentation rate of approximately 14.5 m.y., is terminated by a
Callovian/Oxfordian boundary hiatus, and the overlying upper
Oxfordian through lowest Tithonian clay-rich radiolarites and the