pubmed.ncbi.nlm.nih.gov

Bioerosion of Inorganic Hard Substrates in the Ordovician of Estonia (Baltica) - PubMed

  • ️Thu Jan 01 2015

Bioerosion of Inorganic Hard Substrates in the Ordovician of Estonia (Baltica)

Olev Vinn et al. PLoS One. 2015.

Abstract

The earliest bioeroded inorganic hard substrates in the Ordovician of Estonia appear in the Dapingian. Hardgrounds are also known from the Sandbian and Katian. Most of the bioerosion of inorganic hard substrates occurs as the boring Trypanites Mägdefrau, 1932 along with some possible Gastrochaenolites borings. North American hardground borings are more diverse than those in Baltica. In contrast to a worldwide trend of increasing boring intensity, the Estonian record seems to show no increase in boring intensities during the Middle and Late Ordovician. Hardgrounds seem to be more common during the temperate climate interval of the Ordovician calcite sea in Estonia (seven hardgrounds during 15 my) than in the part with a tropical climate (four hardgrounds during 12 my). Bioerosion is mostly associated with carbonate hardgrounds, but cobbles and pebbles broken from the hardgrounds are also often penetrated by Trypanites borings. The general diversity of boring ichnotaxa in Baltica increased from one ichnospecies in the Cambrian to seven by the end of Ordovician, showing the effect of the GOBE on bioeroding ichnotaxa. The diversity of inorganic hard substrate borers increased by only two times. This difference can be explained by the wider environmental distribution of organic as compared to inorganic substrates in the Ordovician seas of Baltica, and their more continuous temporal availability, which may have caused increased specialization of several borers. The inorganic substrates may have been bioreroded only by the generalists among boring organisms.

PubMed Disclaimer

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. Locality map.

Localities in Estonia.1 Väike-Pakri, 2 Cape Pakri, 3 Vasalemma, 4 Alliku, 5 Suhkrumägi.

Fig 2
Fig 2. Stratigraphy of Pakri cliff.

Modified after Hints et al. (2008). Red-hardgrounds. Blue-cobbles and pebbles.

Fig 3
Fig 3. Stratigraphy of Vasalemma quarry.

Modified after Kröger et al. (2014).

Fig 4
Fig 4. Stratigraphic scheme.

The Middle and Upper Ordovician in Estonia with inorganic hard substrates and Trypanites shown. Modified after Hints et al. (2008). Scale showing Trypanites per 4 cm2. One unit on scale = 10 Trypanites borings. Red-hardgrounds. Green-pebbles/cobbles.

Fig 5
Fig 5. Longitudinal sections of Trypanites.

A generalization from studied samples.

Fig 6
Fig 6. Hardground with Trypanites.

The Alliku hardground, limestone (early Sandbian) from northern Estonia. GIT 362–115.

Fig 7
Fig 7. Hardground with Trypanites.

The Alliku hardground, limestone (early Sandbian) from northern Estonia. GIT 362–114.

Fig 8
Fig 8. Hardground with Trypanites.

The Vasalemma hardground 1, micritic-peloidal limestone (earliest Katian) from NW Estonia. GIT 362–95.

Fig 9
Fig 9. Hardground with Trypanites.

Longitudinal section through Vasalemma hardground 1, micritic-peloidal limestone (earliest Katian) from NW Estonia. GIT 222–499.

Fig 10
Fig 10. Hardground with Trypanites.

Saxby hardground (limestone) from the late Katian of Vormsi Island, western Estonia. GIT 362–98.

Fig 11
Fig 11. Pebble with Trypanites.

Toila Formation (Dapingian) from Suhkrumägi, dolomitized glauconitic limestone, northern Estonia. GIT 156–356.

Fig 12
Fig 12. Paleobiogeography of borings.

Inorganic hard substrates in the Ordovician. The paleogeographic map of Middle Ordovician is modified after Levin (2006). Data are based on Palmer and Palmer (1977), Wilson and Palmer (1988), Ekdale and Bromley (2001) and present work.

Similar articles

Cited by

References

    1. Raukas A, Teedumäe A. (1997) Geology and Mineral Resources of Estonia. 436 pp.; Tallinn: (Estonian Academy Publishers; ).
    1. Wilson MA, Palmer TJ (1992) Hardgrounds and hardground faunas. Univ Wales Aberystw Inst Earth Stud Publ 9: 1–131.
    1. Palmer T (1982) Cambrian to Cretaceous changes in hardground communities. Lethaia 15: 309–323.
    1. Brett CE, Liddell WD (1978) Preservation and paleoecology of a Middle Ordovician hardground community. Paleobiology 4: 329–348.
    1. Brett CE, Brookfield ME (1984) Morphology, faunas and genesis of Ordovician hardgrounds from southern Ontario, Canada. Palaeogeogr Palaeoclimat Palaeoecol 46: 233–290.

Publication types

MeSH terms

Substances

Grants and funding

Financial support to O.V. was provided by the Palaeontological Association Research Grant, Estonian Research Council projects ETF9064 and IUT20-34.

LinkOut - more resources