radiolaria - Marum

Bibliography - 1991 Radiolaria 14
Maastrichtian Madarayama Formation. Based on the stratigraphical
features and radiolarian dating, the Takatoyasan Formation is
presumed to be a product of the convergent complex of an oceanic
plate in trench environment The structure and sedimentary facies of
the Mikado and Madarayama Formations are comparable to those of
the Cretaceous Shimanto Belt in Shikoku and Kii.
Kiesling, W. & Zeiss, A. 1991/92. New
palaeontolgical data from the Hochstegen Marble (Tauern
window, eastern Alps). Geol. Pälont. Mitt. Innsbruck, 18,
187-202.
Two new species and one new genus of Radiolaria are described
from the greenschist-metamorphic Hochstegen Marble of the Tauern
Window. Despite of strong shearing deformation the microstructure
is sufficiently preserved for species determination, due to early
diagenetic pyritization of the siliceous skeletons. The new
radiolarians belong to a Kimmeridgian to Lower Tithonian
assemblage. They are part of a highly diverse fauna of radiolarians
and sponge spicules recovered from the HCI-insoluble residue of the
Hochstegen Marble.
The famous 'ammonite from the street wall' could firstly be
determined on a species level as Orthosphinctes (Lithacosphinctes)
siemiradzkii n.nom. [pro 'O. (L.) evolutus QUENSTEDT]. The ammonite
is proof of Uppermost Oxfordian age for the dolomite quarry near
Mayrhofen. The taxonomical and nomenclatorical problems of the O
.(L.) siemiradzkii as well as that of the related species O. (O.)
polygyratus and O. (O.) tiziani are explained in detail.
Kito, N. & Chitoku, T. 1991. Geologic age of the
mosasaurian fossil from Hobetsu-cho, Hokkaido, Japan. Sci.
Rep. Hobetsu Mus., Hokkaido, 7, 9-14. (in Japanese)
Kojima, S., Wakita, K., Okamura, Y., Natal'in,
B.A., Zyabrev, S.V., Qing, L.Z. & Ji, A.S. 1991.
Mesozoic radiolarians from the Khabarovsk Complex,
eastern USSR; their significance in relation to the Mino
Terrane, central Japan. J. geol. Soc. Japan, 97/7, 549-551.
In the course of the geotectonic studies on "geosynclines" in
Northeast Asia, Japanese geologists (e.g, Kobayashi, 1984; Noda,
1956) have focused their interests on the complicated sedimentary
formations in the Sikhote-Alin region in relation to the Japanese
"Paleozoic" stratigraphy. Especially, Noda (1956) introduced the
occurrence of Radiolaria bearing siliceous formations near
Khabarovsk, although he regarded the rocks as the Permian. After
that, Russian paleontologists and biostratigraphers have reported
Mesozoic radiolarians from the Sikhote-Alin Range, including the
Khabarovsk area (e.g, Zhamoida, 1972; Tikhomirova, 1986); most
of their works, however, were based on observations under the
optical microscope.
In this article, we describe the occurrence of Triassic and
Jurassic radiolarians from the Khabarovsk complex, eastern USSR
(stipple pattern in the inset map of Fig. 1), and discuss
paleontological, stratigraphical and structural similarities between
the Khabarovsk complex and the Mino terrane in central Japan.
Kozur, H. 1991. The evolution of the Meliata-Hallstatt
ocean and its significance for the early evolution of the
Eastern Alps and Western Carpathians. Palaeogeogr.
Palaeoclimatol. Palaeoecol., 87/1-4, 109-135.
The evolution of the Meliata-Hallstatt ocean and of its southern
and northern margin in the Inner Western Carpathians are described.
The main rifting began during the Pelsonian and the sea-floor
spreading ended at the beginning of the Middle Carnian
contemporaneously with the Raibl event. The subduction began in the
latest Triassic and the final closing of the ocean, accompanied by
uplift of the adjacent marginal areas, was dated as basal Oxfordian.
Remnants of the oceanic-suboceanic sequence occur in two tectonic
positions: (I) Obducted nappes that contain, mostly as tectonic
melanges, the whole Middle Triassic to Middle Jurassic sequence,
including large bodies of dismembered ophiolites of Ladinian to Early
Carnian age. (2) Evaporite melanges at the base of nappes that are
derived from the northern margin of the ocean. These evaporite
melanges consist of Late Permian evaporitic matrix and blocks of a
dismembered Ladinian to Lower Carnian ophiolitic sequence.
In the Inner Western Carpathians both the northern and southern
marginal sequences of the Meliata-Hallstatt ocean and the
transitions into the carbonate platforms are present in different
nappes. The southern marginal development is characterized by
Middle Carnian distal clastic Raibl Beds and by Middle Jurassic
rhyolithic volcanism, both missing in the northern marginal
development. Because the subduction-related Middle Jurassic
volcanism (contemporaneous with the turbidites in the southern
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Meliaticum) is restricted to the marginal area south of the Meliata-
Hallstatt ocean, southward-directed subduction is indicated. To the
south, on the adjacent carbonate platform, a Jurassic basin with
Aalenian to Bajocian ophiolites opened. This may be a back-arc basin.
In the Eastern Alps only the northern marginal zone and the
adjacent carbonate platform are preserved, but parts of the
dismembered ophiolites in the Haselgebirge may be of Ladinian to
Late Carnian age like in evaporitic melanges in the same tectonic
position in the Inner Western Carpathians.
The final closing of the Meliata-Hallstatt ocean is indicated by
the abrupt end of the turbiditic sedimentation in the oceanic
suboceanic domain and by uplift in the marginal areas, where Lower
Oxfordian radiolarites are overlain by shallow-water Upper Oxfordian
to Tithonian or Neocomian limestones (Silica Nappe, Hallstatt
Nappes). With the evidence of the final closing of the Meliata-
Hallstatt ocean near the Middle/Late Jurassic boundary, the
Cimmerian orogenesis (in the genetic sense of Sengor, 1984, 1985)
is now also proven in the Inner Western Carpathians and in the
Eastern Alps.
A continuation of the Meliata-Hallstatt ocean into the Pontide
"Paleotethys" (=Cimmerian ocean sensu Kozur, 1990) through the
Transylvanian oceanic domain and the Strandzha Unit is assumed. A
connection with the Vardar ocean is impossible, because in the
Vardar Zone no Triassic ophiolites or basic volcanics are present and
the ophiolites have Jurassic age.
Kozur, H. & Mostler, H. 1991. Erster
paläontologischer nachweis von meliaticum und südrudabányaicum
in den nördlichen kalkalpen (Östereich) und
ihre beziehungen zu den abfolgen in den westkarpaten. Geol.
Pälont. Mitt. Innsbruck, 18, 87-129.
For the first time, a sedimentary sequence of the Meliaticum
has been paleontologically dated by conodonts and radiolarians in
the Northem Calcareous Alps . Middle Triassic red radiolarites,
silicified pelagic red limestones ( ' chert ' ) and subordinately pelagic
limestones occur as olistoliths in a Middle Jurassic sequence of
partly graded shales and siltstones, some sandstones and numerous
olistoliths. This sedimentary Meliaticum that has been found at the
Florianikogel and in the Edenhof window, is part of a nappe named as
Florianikogel Nappe. In the Edenhof multiple window, serpentinit is
present subordinately. At the Florianikogel light-coloured, crystalline
limestones of the pre-(oceanic) rift stage are present that can be
also found in marginal suboceanic parts of the Meliaticum in the
Westem Carpathians. Tectonically dismembered ophiolites of the
Meliaticum are present in a narrow E-W to ENE-WSW striking zone
running from Unter-Hoflein in the east across Pfennigbach, western
Mariazell-Puchberg line to Grundlsee in the west. These ophiolites
occur mostly in salinar melanges. They indicate seemingly the suture
zone of the Meliata-Hallstatt ocean. This zone is narrow and no
segments of this zone are displaced distinctly in N-S direction.
Therefore a large-scale nappe transport of upper parts of the
original suture of the Meliata-Hallstatt ocean from the area near to
the Alpin-Dinaric Line is not probably. The tectonic consequences for
the nappe structure of the Eastem Alps are discussed.
Unmetamorphic South-Rudabanyaicum was found near the southem
margin of the Northem Calcareous Alps . These units were originally
situated south of the Meliata-Hallstatt ocean. The Geyerstein Nappe
is introduced for this sequence. Additionally, low-grade metamorphic
remnants of South-Rudabanyaicum are present in the Edenhof
multiple window. The upper part of the Lower Anisian and the Lower
Pelsonian are pelagic and in the Pelsonian reworked basic volcancis
can be found beside numerous reworked limestones. These basic
volcancis indicate a transitional position of this South-
Rudabanyaicum to the Meliaticum.
Kurimoto, C. & Kuwahara, K. 1991. Radiolarians from
the Ojigahata area of Shiga Prefecture, southwestern part of
the Mino Terrane. Bull. geol. Surv. Japan, 42/2, 63-73. (in
Japanese)
Strata of the Mino Terrane which are distributed in the study
area are called the Ojigahata Formation. The Ojigahata Formation
consists mainly of chert associated with mudstone and sandstone,
and belongs to the sandstone-chert facies of the Mino Terrane.
Chert and mudstone of the Ojigahata Formation were collected to
extract microfossils. As a result, radiolarians available for agedetermination
were obtained from 12 samples. Radiolarian
assemblages from chert are correlated with those of Middle Triassic,
Late Triassic and Early Jurassic ages. On the other hand, radiolarian
assemblages from mudstone are correlated with those of middle
Middle Jurassic and late Middle to early Late Jurassic ages. Judging
from the above-mentioned data, the Ojigahata Formation represents
a coarsening-upward sequence which consists of Middle Triassic to
Early Jurassic chert, Middle Jurassic mudstone and Middle to Late
Jurassic interbedded sandstone and mudstone.