radiolaria - Marum

Bibliography - 1991 Radiolaria 14
Yokomichi Village. Matsumaru & Kimura (1989) found the Eocene
larger foraminifera from the gray tuffaceous mudstone of the
Shimizu Formation at Takahata Village, but the present authors
consider the location belongs to the Kurusuno Formation from the
view point of lithologic characteristics. The boundary between the
two formations is now considered to be further south than the
original boundary of Kimura (1985). They also found Eocene larger
foraminifera from the Shimizu Formation at Yokomichi, South of
Tosashimizu City. Judging from the larger foraminifera, Kimura
(1985) interpreted the age of the Shimizu Formation corresponding
to the age ranging from Late Eocene to Late Oligocene, and
correlated the formation to the Nichinan Group in Miyazaki
Prefecture. He interpreted that the Shimizu Formation is an originally
submarine slide deposits and may contain older clasts and blocks
ranging from Cretaceous to Eocene from an uplifted accreted
terrane.
On the other hand, we found the Late Oligocene or possible
Early Miocene larger foraminifera (Nephrolepidolina morgani and
Spiroclypeus sp., determined by Matsumaru, personal
communication, 1990) from the volcanic pebble-bearing mudstone
exposed along the coast line of the southern part of the Ohki beach.
Detailed studies are now held, but we might therefore suggest most
of the Shimizu Formation is of Oligocene to possible Early Miocene
age, and includes some older Cretaceous blocks described here.
Fossils had not previously been found from the deformed sediments
around Tsuro, the south- ernmost part of the Shimizu Formation near
Ashizuri Cape, where we found Late Cretaceous radiolarians
reported here (Figs. 1 and 2). The fossils were collected from the
mud dominated part of the clast of sandy turbidite within the pebbly
mudstone (Fig. 3). This clast is fault bounded so that its
stratigraphic position is unknown anywhere in this locality.
Tipper, H.W., Smith, P.L., Cameron, B.E.B.,
Carter, E.S., Jakobs, G.K. & Johns, M.J. 1991.
Biostratigraphy of the Lower Jurassic formations of the
Queen Charlotte Islands, British Columbia. In: Evolution and
Hydrocarbon Potential of the Queen Charlotte Basin, British
Columbia. Eds.), vol. 90-10. Geological Survey of Canada,
Paper, pp. 203-235.
The Lower Jurassic strata of Queen Charlotte Islands have been
divided into five lithologically distinct formations, namely: the
Sandilands Formation of the Kunga Group and the Ghost Creek,
Fannin, Whiteaves, and Phantom Creek formations of the Maude
Group. The Rennell Junction unit is abandoned as a formation and the
beds included within a redefined Fannin Formation.
Macrofossils, particularly ammonites, and microfossils, notably
Radiolaria, Foraminifera, Ostracoda, and ichthyoliths, are abundant,
generally well-preserved, reasonably diverse, and are found, to a
degree, in all formations. The record suggests a complete Lower
Jurassic sequence with few, if any, hiatuses of consequence. The
Pliensbachian ammonite zonation for North America is defined by
stratotype and reference sections in Skidegate Inlet. Toarcian
Radiolaria likewise have been zoned. The biostratigraphic studies of
all faunas has as a goal, zonations based on many faunas and a
satisfactory correlation of these schemes. Important macrofossils
and microfossils are illustrated and zones and faunal assemblages
have been described. The importance of fossils to mappers and
stratigraphers and the application of these data to an understanding
of paleogeography and tectonics is emphasized.
Tonielli, R. 1991. Associazioni a radiolari dei "Calcari e
Marne a Posidonia del Monte Terminilletto (RI).
Paleopelagos, 1, 18-37.
An Aalenian-Bajocian assemblage referred to the "Hsuum
hisuikyoensis" zone (Hori, 1990) and to the range between 6 and 7
zones defined by Carter (1988) is recognized in the "calcari e
marne a Posidonia" Auct. of the Terminilletto (Ri) sequence; this
assemblage testifies for the first time, even in the Central Italy, the
presence of Middle Jurassic.
Treguer, P. & Van Bennekom, A.J. 1991. The annual
production of biogenic silica in the Antarctic Ocean. Marine
Chem., 35, 477-487.
The total annual production of biogenic silica (BSi) of the
Antarctic Ocean is estimated at about 50 tera (T= 10 12 ) mol Si.
This flux is calculated using available direct measurements of
integrated silicic acid uptake rates, indirect estimates from field
distribution of orthosilicic acid in austral winter compared with that
in austral summer and/or after conversion of 14 C primary
production using appropriate Si/C mole ratios measured for the four
Antarctic subsystems: the Polar Front Zone, the Permanently Open
Ocean Zone, the Seasonal Ice Zone, and the continental shelves and
coastal zones. We show that most of the total production of BSi
occurs in the surface layers of the Permanently Open Ocean Zone
- 72 -
and in the Seasonal Ice Zone, the contribution of the coastal areas
being less relevant. Our results fit well with the previously described
distributions of the net accumulation rates of opal in Antarctic
abyssal and coastal sediments. The mean ratio of net opal
accumulation at the sea-bed to the net production of BSi in the
surface layer of the Antarctic Ocean is about 15%.
Tsutsumi, A. 1991. Re-examination of stratigraphy and
geological structure of the upper Paleozoic formations in the
Ibara City, southwestern Okayama Prefecture. J. geol. Soc.
Japan, 97/3, 197-216. (in Japanese)
The Maizuru Belt and the Ultra-Tamba Belt are ENE-WSW
trending structural belts which stretches from Kyoto Prefecture to
the middle part of Okayama Prefecture. The surveyed area is
situated at the westward extension of these structural belts. The
Paleozoic group which crops out in the area is divided into three E-W
trending zones, which are juxtaposed one another bounded by faults.
The constituent strata of each zone are newly named the Saya,
Shimoshigi and Hiehara Formations. The Saya Formation, more than
500 m thick, is composed chiefly of slate with subordinate amounts
of chert laminite and acidic and basic volcanic rocks. Most of these
rocks are fissile due to the development of slaty cleavage. The
Shimoshigi Formation, approximately 750 m thick, is subdivided into
the lower and upper members; the former is composed mainly of
basic volcanic rock and the latter of slate and alternating beds of
slate and sandstone with subordinate coglomerate. The slate is
characterized by a well-developed slaty cleavage. Radiolarian
assemblages indicate that the upper member is Middle to Early
Permian in age. The Hiehara Formation, more than 2000 m thick, is
also subdivided into the lower and upper members. The lower member
is composed of slate, pebbly slate, acidic and basic volcanic rocks
with minor amounts of chert and red slate, while the upper member
consists mainly of basic volcanic rock Based on analysis of
structural elements, such as slaty cleavage, lineation and fold axis,
three deformation stages are recognized in the structural
development of the Saya and the Shimoshigi Formations and two
deformation stages of the Hiehara Formation. During the first
deformation stage, closed to tight folds with an axial plane slaty
cleavage were formed. During the subsequent second stage of
deformation open folds were formed. In the Saya and Shimoshigi
Formation the second deformation is associated with formation of
crenulation cleavages. Then the Saya and Shimoshigi Formations
underwent the third deformation process characterized by kink folds
that are locally superposed on the earlier structures.
Ujiie, H. & Oba, T. 1991. Geology and Permo-Jurassic
Radiolaria of the Iheya Zone, Innermost Belt of the Okinawa
Islands region, middle Ryukyu island arc, Japan. Part 1.
Geology and Permian Radiolaria. Part 2 Mesozoic Radiolaria
and geological structures. Bull. College Sci., Univ. Ryukyus,
51, 35-89.
Umeda, M. 1991. Clastic dike in the Jurassic sequence in
the western part of the Nanjo Massif, the Mino terrane,
central Japan. In: Prof. Miura, S. - Memorial Volume. Eds.).
pp. 89-95. (in Japanese)
Vishnevskaya, V.S. 1991. Radiolarian layers of the
USSR late Mesozoic. Izv. Akad. Nauk SSSR, ser. geol., 2,
57-81. (in Russian)
A radiolarian biostratigralphy of Late Mesozoic units in the
USSR is presented. It is based on three main regions: the Far East,
the central regions and the south-vest of the USSR. Eleven typical
radiolarian layers are suggested for the Jurassic-Cretaceous
volcanogenic-siliceous units in the Far Eastern region of the USSR.
Thirteen radiolarian layers are recognised in the siliceous-carbonate
deposits of the Bol'shoy and Maly Kavkaz (Caucasus). These
deposits are characterised by different kinds of fauna, namely
ammonites, Inocerami and foraminifera. The radiolarian layers may
be used in ecological surveys.
Vishnevskaya, V.S., Filatova, N.I. &
Dvoryankin, A.I. 1991. New data on Jurassic sediments
of Semiglavaya Mountain (Koryak Highland). Izv. Akad.
Nauk SSSR, ser. geol., 4, 21-30. (in Russian)
Detailed geological mapping was carried out in areas of the
Koyverelan-Malyy Nauchirnynay interfluve and followed by
laboratory analysis involving layer-by-layer sampling for radiolaria.
This showed that the volcanogenic-siliceous-carbonate deposits in
the region of Mount Semiglavaya, which form a series of tectonic
plates pressed between Albian-Cenomanian terrigenous formations,
include rocks not only of Upper Jurassic-Neocomian, but also of
Middle Jurassic age. Analogous Middle Jurassic formations have also
been discovered in the basins of the rivers Talyakaurkhyn and Malyy
Nauchirnynay, where they occur as faulted tectonic plates or thin