radiolaria - Marum

Bibliography - 1992 Radiolaria 14
data for both Japan and North America. Because of the vast amount
of unpublished data from both North America and Japan, it was first
necessary for the authors to meet and to examine hundreds of
scanning electron photomicrographs of North American and
Japanese Radiolaria. Without such a meeting, any attempt at
correlating North American and Japanese Jurassic radiolarian
biozones would have been, at best, an exercise in futility (plates 99-
102). The radiolarian zonation for North America followed herein
represents an emended version of that presented by Pessagno et al.
(1987b). The North American zonation shown in Figure 14.1 is the
result of over 10 years of field and laboratory investigations by
Pessagno and his associates. North American Jurassic samples were
analyzed from Alaska, the Queen Charlotte Islands (British
Columbia), east-central Oregon, California, Baja California Sur, and
east-central Mexico. In establishing a zonal scheme for the North
American Jurassic, Pessagno et al. (1987b) calibrated the
radiolarian biostratigraphy with those of the ammonites,
calpionellids, Buchia, and other well-studied fossil groups. This
amalgamation of data allowed a fit of the radiolarian zonation to the
ammonite-based chronostratigraphic scale. Figures showing the
approximate correlation of radiolarian zonal units with ammonite
standard zones were presented by Pessagno et al. (1987b) and are
not included here.
Emendations to the original zonal scheme are minor. They
include the introduction of a new subzone, Subzone 2 gamma, and
the subsequent redefinition of Subzone 2 beta (Pessagno, Six, and
Yang 1989). Subzone 2 gamma is defined from new data (Smith
River Subterrane, Klamath Mountains, northwestern California)
(Pessagno and Blome 1988, 1990) that document an interval of
concurrence between the first appearance of Mirifusus Pessagno
and the final appearance of Xiphostylus Haeckel ( primary marker
taxa). The base of overlying Subzone 2 beta (Figure 14.1) is
redefined to occur in the interval immediately above the final
occurrence of Xiphostylus, whereas its top occurs immediately below
the first occurrence of Parvicingula Pessagno s.s. Further discussion
of the biostratigraphic, chronostratigraphic, and geochronological
significance of Subzone 2 gamma is presented later.
The Japanese radiolarian zonation presented herein is that of
Matsuoka and Yao (1986). This zonal scheme has become the
standard for the western Pacific. Ammonites and other megafossils
are very rare or totally absent from the Japanese radiolarian-bearing
succession (e.g., Mino terrane). Hence, the chronostratigraphic
assignment of Japanese Jurassic radiolarian biozones is based on
North American data or data from elsewhere.
Podobina, V.M. & Amon, E.O. 1992. Microfauna and
biostratigraphy of Paleogene deposits of the Section
"Sarbay" North-Western Turgay. In: Materials on
Paleontology and Stratigraphy of the Western Siberia.
(Podobina, V.M., Eds.). Tomsk Univ. Publisher, Tomsk. pp.
88-96. (in Russian)
Sakai, T. & Aita, Y. 1992. Proceedings of the Third
Radiolarian Symposium. News of Osaka
Micropaleontologists, special Volume, 8. Osaka, Japan.
100 p.
Sakai, T., Okada, H. & Aihara, A. 1992. Cretaceous
and Tertiary active margin sedimentation: transect of Kyushu.
In: Paleozoic and Mesozoic Terranes: Basement of the
Japanese Island Arcs. 29th IGC Field Trip Guide Book.
(Adachi, M. & Suzuki, K., Eds.), vol. 1. Nagoya University,
Nagoya, Japan. pp. 317-354.
Sancetta, C. 1992. Primary production in the glacial North
Atlantic and North Pacific Oceans. Nature, 360/6401, 249-
251.
The conditions controlling primary production are very different
in the modem North Atlantic and North Pacific oceans, a difference
that is reflected in the composition of diatom fossils in surface
sediments. By contrast, I report here evidence that during the last
glacial interval the diatom assemblage, and by extrapolation the
primary production, was very similar in the two regions. The modem
analogues of these assemblages occur in sediments of Baffin Bay
and the Sea of Okhotsk, both highly productive seas where ice is
present. I infer that during the last glacial internal plankton biomass
was at least as high as it is today in the North Atlantic, and was as
much as an order of magnitude I higher in the North Pacific. I
hypothesise that the presence of numerous icebergs, possibly
associated with sea ice I supported high production of physical
mechanisms (such as turbulent mixing and enhanced density
stratification) and/or biogeochemical ones (such as supply of major
or trace nutrients)
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Sanfilippo, A. & Riedel, W.R. 1992. The origin and
evolution of Pterocorythidae (Radiolaria): A Cenozoic
phylogenetic study. Micropaleontology, 38/1, 1-36.
A survey of pterocorythids throughout the Cenozoic shows that
there are only two generalized, persistent stocks from which
developed fourteen branches here treated as genera or subgenera.
These branchings are the "speciations" of evolutionists, but we use
the term "species" for chronospecies which would be subdivisions of
the evolutionists anagenetic species. Thus we distribute the
approximately fifty pterocorythid genera previously recognized
among only sixteen genus-level taxa. We have found it necessary to
describe the new genera Cryptocarpium and Albatrossidium, and the
subgenera Calocyclior, Calocyclissima, Calocyclopsis, Podocyrtopsis
and Podocyrtoges, as well as six new species to clarify generic
origins and terminations.
Cephalic structure tends to be conservative and distinctive at
the generic level, as also does to a somewhat lesser extent the
shape of the thorax and the nature of its wall and pores. More distal
parts of the skeleton vary markedly within genera. Relationships can
be determined only by following evolutionary changes through time in
many cases, superficially similar species have quite different
evolutionary origins.
Sano, H., Wakita, K., Kojima, S. & Yamagata, T.
1992. Late Mesozoic accretionary complex: Mino Terrane,
Central Japan. In: Paleozoic and Mesozoic Terranes:
Basement of the Japanese Island Arcs. 29th IGC Field Trip
Guide Book. (Adachi, M. & Suzuki, K., Eds.), vol. 1. Nagoya
University, Nagoya, Japan. pp. 197-203.
Our field trip examines the stratigraphy, lithology, and
structure of Paleozoic and Mesozoic rocks of the Mino terrane and
intends to discuss its origin and tectonic evolution. The trip plans to
meet rocks of the Mino terrane seven stops in the Neo-Miyama area,
central Japan (Fig. 1). The Mino terrane is extensive in the
continental side of Southwest Japan (Fig. 1). Its correlative terranes
are described in northeast China and Sikhote-Alin (Kojima, 1989), in
North Palawan, the Philippines (Isozaki et al., 1988), and on
Ishigakijima Island at the southwestern extremity of Japan (Isozaki
and Nishimura, 1989). The Mino terrane and its correlatives form a
belt of Jurassic accretionary rocks fringing the western Pacific
margin (Mizutani, 1987). The Mino terrane comprises a lithologically
heterogeneous and structurally complicated aggregate of
unmetamorphosed Paleozoic and Mesozoic rocks. Its major
constituents are Permian basaltic rocks, carbonates, and chert,
Triassic to Jurassic chert and related siliceous rocks, and Jurassic
to lowest Lower Cretaceous sandstone and mudstone. The Jurassic
terrigenous rocks are most extensive in the Mino terrane. These
rocks are strongly deformed and form a series of fault-bounded,
complexly stacked, originally southerly vergent, imbricated
structural wedges. The complexly stacked wedges have been folded
to form gentle synclines and anticlines on a mappable scale
(Mizutani, 1964). The deformed rocks of the Mino terrane are
unconformably covered by less deformed Late Cretaceous effusive
rocks.
Sano, H., Yamagata, T. & Horibo, K. 1992.
Tectonostratigraphy of Mino terrane; Jurassic accretionary
complex of southwest Japan. 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. 41-57.
The Mino terrane, a disrupted accretionary terrane in central
Japan, consists of four fault-bounded mappable units of Mesozoic
and Paleozoic unmetamorphosed sedimentary rocks. The four units
are described as (I) Permian greenstonecarbonate-chert unit, (2)
Lower Triassic to lowest Cretaceous siliceous pelagite-distal
turbidite unit, (3) Middle Jurassic proximal turbidite unit, and (4)
upper Lower Jurassic to lowest Cretaceous olistostrome-slump unit.
The first unit is interpreted as a sedimentary cover which was
formed on and around a seamount in an open-ocean setting. The
second unit records the accumulation of deep-water radiolarian-rich
sediments in a pelagic realm and a tapering wedge of trench
turbidites. The third unit contains submarine fan sediments
deposited in a possible trench-slope basin. The forth unit, labelled as
sedimentary melange containing blocks derived from accretionary
prisms, is considered to be submarine deposits which accumulated in
a lower trench-slope basin to trench floor setting.
An originally southward-vergent imbricate stacking of
structural wedges of these four units characterizes the highly
complicated structure of the Mino terrane rocks. Collision and
subsequent offscraping accretion of Permian to Middle Jurassic
oceanic rocks and Lower Jurassic to lowest Cretaceous clastic rocks
provide the most satisfactory explanation for juxtaposition of the
structural wedges of the four units which were originally laid down in