Stratigraphical section through Lower Cambrian at Söderfjärden, Vaasa, western Finland

Lehtovaara, Jyrki J.

doi:10.17741/bgsf/54.1-2.004

Cited by 12 publications

(13 citation statements)

References 4 publications

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“…The roundness of the grains is well developed. In comparison with other relatively adjacent Cambrian deposits of the Bothnian Sea region, from Aland (Simonen and Kouvo 1955), the western shoals of the Bothnian Sea (Thorslund and Axberg 1979) and Söderfjärden, Vaasa (Lehtovaara 1982b), it appears that the sandy material of the Olkiluoto boulder represents the very coarsest fractions that settled in the commonly fine-grained Cambrian clastic layers.…”

Section: Mineralogy and Petrologymentioning

confidence: 79%

“…Winterhalter and Siivola (1967) have run an electron microprobe study of the recent FeMn concretions from the bottom of the Gulf of Bothnia. These also display a rather high phosphorus content averaging 3.5 % and phosphorus thus seems to continue to be relatively enriched in the area since the Cambrian (see analyses in Lauren et al 1978 andLehtovaara 1982b). …”

Section: Mineralogy and Petrologymentioning

confidence: 97%

“…Lehtovaara 1982a), but they rarely contain fossils. Impetus to the present study was given by a spectacularly fossili- ferous boulder of conglomeratic sandstone delivered to the Institute of Geology and Mineralogy of the University of Turku by Mr. Matti Tirronen.…”

Section: Discoverymentioning

confidence: 99%

“…As far as the general mineralogy and petrology of the sample are concerned, provided the characteristics described are taken into account, the rock is reminiscent of coarser sedimentary rocks from the Söder-fjärden basin (Laurén et al 1978;Lehtovaara 1982b) or those from the bottom of the Bothnian Sea (Thorslund and Axberg 1979). The Olkiluoto sample is, of course, exceptionally fossiliferous but it does not differ in the quality of minerals or diagenesis.…”

Section: Comparisons Of Originmentioning

confidence: 99%

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Fossiliferous boulders of Lower Cambrian phosphoritic sandstone in southwestern Finland

Lehtovaara¹,

Tynni²

1983

Bull Geol Soc Finland

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Section: Mineralogy and Petrologymentioning

confidence: 79%

Section: Mineralogy and Petrologymentioning

confidence: 97%

Section: Discoverymentioning

confidence: 99%

Section: Comparisons Of Originmentioning

confidence: 99%

See 2 more Smart Citations

Fossiliferous boulders of Lower Cambrian phosphoritic sandstone in southwestern Finland

Lehtovaara¹,

Tynni²

1983

Bull Geol Soc Finland

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“…In part, this is because surviving sedimentary cover on Finland from the Proterozoic and early Palaeozoic is particularly restricted in extent in comparison with other regions of Baltica. In some areas, however, sedimentary cover has escaped erosion within the protective depressions of impact craters (Lehtovaara , ).…”

mentioning

confidence: 99%

Early Cambrian small carbonaceous fossils (SCFs) from an impact crater in western Finland

Slater

Willman

2019

LET

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We describe an assemblage of small carbonaceous fossils (SCFs) and acritarchs from cored siltstones of the Lappajärvi impact structure, west‐central Finland. Previous studies had detected a depauperate acritarch biota ascribed to a deep Proterozoic origin—this age, however, was based on recovery of long‐ranging poorly age‐diagnostic sphaeromorphs. To resolve the age and provenance of these crater sediments, we applied low‐manipulation processing techniques optimized for retrieval of larger organic‐walled microfossils. Our study revealed a previously undetected assemblage containing numerous metazoan SCFs consisting of flattened ‘protoconodonts’ (grasping spines assignable to total group Chaetognatha) and a distinctive fossilised chaeta, possibly representing the oldest known annelid remains. Phylogenetically problematic fossils include various acritarchs (large Leiosphaeridia sp., Tasmanites tenellus, smaller sphaeromorphs, Synsphaeridium, Archaeodiscina and Granomarginata) and filamentous forms (Palaeolyngbya‐ and Rugosoopsis‐like filaments, Siphonophycus), likely representing prokaryotic or protistan grades of organisation. As well as adding new diversity to an emerging SCFs record, these data substantially refine the age of these sediments by more than half a billion years, to an early Cambrian Terreneuvian age. More specifically, the assemblage is equivalent to that of the Lontova Formation from the Baltic States and northwest Russia, but is previously unreported from Finland. Identification of Lontova‐type SCFs/organic‐walled microfossils at Lappajärvi further constrains the poorly resolved extent of maximum flooding during the early Cambrian in Baltica. Renewed attention should be directed to strata that have thus far produced only biostratigraphically long‐ranging or ambiguous palynological assemblages—‘SCF‐style’ processing can reveal hitherto undetected, age‐informative microfossils that are otherwise selectively removed in conventional palynological studies.

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Settings of Meteorite Impact Structures in the Svecofennian Crustal Domain

Puura

Plado

Impact Studies

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Stratigraphical section through Lower Cambrian at Söderfjärden, Vaasa, western Finland

Cited by 12 publications

References 4 publications

Fossiliferous boulders of Lower Cambrian phosphoritic sandstone in southwestern Finland

Fossiliferous boulders of Lower Cambrian phosphoritic sandstone in southwestern Finland

Early Cambrian small carbonaceous fossils (SCFs) from an impact crater in western Finland

Settings of Meteorite Impact Structures in the Svecofennian Crustal Domain

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