CONTENTS & ABSTRACTS
In English. Summaries in Estonian and Russian
Proceedings of the Estonian Academy of Sciences
Volume 49 No. 1 March 2000
- The Billingen and Volkhov stages in the northern East Baltic: detailed
stratigraphy and lithofacies zonation; 3–16
- Andrei DRONOV, Tõnu MEIDLA, Leho AINSAAR, and Oive TINN
- Abstract. The formal stratigraphical subdivision of
the Billingen–Volkhov interval is combined with informal detailed
subdivision of the Volkhov sequence in the eastern part of the Baltic–Ladoga
Klint area. A detailed correlation of the successions east and west of the
Narva River is provided, using for the near-klint belt in North Estonia the
bed nomenclature employed by Russian quarrymen, and the principal trends of
the lithofacies changes in the study area are documented. The affinity of
sections in northwestern Russia and Central Estonia is demonstrated and two
lithofacies zones within the North Estonian Confacies Belt are
Key words: Ordovician, Billingen Stage, Volkhov
Stage, lithofacies zones, lithostratigraphy, ostracodes, Estonia,
- Grain micromorphology in the Rannamõisa section, Lower Cambrian, Estonia;
- Tiia KURVITS, William C. MAHANEY, and Volli KALM
- Abstract. Sand and silt grains of Lower Cambrian
siliciclastic rocks in Estonia were studied by the scanning electron
microscope and energy dispersive spectrometer to find out if grain
micromorphology might prove useful in determining clast sedimentologic and
diagenetic history. The majority of grains studied fall in the range of
40–70 mm diameter, have angular shapes, and show
considerable dissolution. The predominant minerals, quartz with minor
amounts of K-feldspar are cemented by silica. Quite possibly these
aggregates are the result of fluctuating water tables in weathering
conditions over a long period of time. Prevalent etching on most grain
surfaces obscures microfeatures that might reveal exact transport histories.
Grain shape, size, and sorting, also sedimentary structures suggest the
material of sandstones at Rannamõisa was transported into the sedimentary
basin mainly in suspension, aeolian and/or fluvial, which permitted no
rounding of grains.
Key words: grain micromorphology, sandstones,
silica, weathering, sedimentology, Lower Cambrian, Estonia.
- The new trilobite genus Valdariops from the Harju Series (Upper
Ordovician) of Estonia; 28–43
- Arvo RÕÕMUSOKS
- Abstract. The species Phacops
(Chasmops) eichwaldi Schmidt, 1881 from the previous Lyckholm
Stage, corresponding to the Nabala, Vormsi, and Pirgu stages, has been
defined by Schmidt (1881, Mém. Acad. Imp. Sci. St.-Petersb., Sér. 7,
30, 1) in a very wide sense and is virtually a composite species.
This species-group is here assigned to a new genus Valdariops, with
the species V. eichwaldi (emended),
V. aliquantulus sp. nov., V. angustus
sp. nov., and V. kernuensis sp. nov. Two additional forms
are figured as Valdariops sp. nov. A and Valdariops sp. nov.
B. All these species have a stratigraphically limited range as guide fossils
for different parts of the sequence of the Harju Series in the North
Estonian Confacies Belt.
Key words: trilobites, Valdariops
gen. nov., Ordovician, Estonia.
- Latest Silurian (Ohesaare Stage) conodonts and the detorta Zone in
the northern East Baltic; 44–62
- Viive VIIRA
- Abstract. The latest Silurian conodonts from the
Sõrve Peninsula of Saaremaa Island, Ruhnu Island, and western Latvia include
Ozarkodina remscheidensis remscheidensis, Oz. confluens,
Oz. nasuta, and Oulodus elegans. They represent the local
nearshore remscheidensis remscheidensis Subzone of the
remscheidensis Zone. The Oulodus elegans detorta Zone occurs
as a short interval in the upper part of the Ohesaare Stage. Three new
species are described: Amydrotaxis? praecox, Oz.
denticulata, and Oz. inordinata. Ozarkodina nasuta (Viira,
1983) was originally described as the subspecies of Oz.
Key words: conodonts, taxonomy, biostratigraphy,
Upper Silurian, East Baltic.
- Instructions to authors; 63