Correlation of Silurian bentonites from Gotland and the eastern Baltic using sanidine phenocryst composition, and biostratigraphical consequences

Abstract

Silurian bentonites from Sweden and the eastern Baltic are correlated using XRD analysis of sanidine composition. Identifying the same bentonite in different sections has constrained correlations between the conodont, graptolite and chitinozoan zonations.

Use of immobile trace elements for the correlation of Telychian bentonites on Saaremaa Island, Estonia, and mapping of volcanic ash clouds

“…Nestor (1997) with indication of the studied interval. The Llandovery-Wenlock boundary is given according to Kiipli et al (2008) In terms of graptolite stratigraphy, the boundary between the Adavere and Jaani stages, which is marked by the Kirikuküla Bentonite, is close to the spiralis-lapworthi boundary (Kiipli et al 2007a). Bentonite names and ID numbers used herein are from .…”

“…Previous works (R. Kiipli et al 2008) have used X-ray diffractometry measurements to identify samples of volcanogenic origin. Good criteria are the occurrence of illite-smectite, authigenic K-feldspar, kaolinite and/or chlorite-smectite, together with low concentrations or absence of quartz.…”

“…Volcanic ashes, deposited almost instantly in a geological sense, may serve as perfect, chronologically fixed marker horizons for stratigraphy (Thorslund 1945;Batchelor & Jeppsson 1994;Bergström et al 1995Bergström et al , 1998Batchelor & Evans 2000;E. Kiipli et al 2006;Kiipli et al 2007aKiipli et al , 2008. To reconstruct the volcanic history of a region, the stratigraphic distribution of numerous ash beds must be identified in different sections.…”

Geochemical variations within the mid-Silurian Grötlingbo Bentonite (Gotland, Sweden): discriminating between magmatic composition, ash transport fractionation and diagenetic effects

“…Volcanic ash beds in sedimentary successions have frequently been used for precise regional correlation of sedimentary sections (Bergström et al 1995;Kiipli et al 2008aKiipli et al , 2010aKiipli et al , 2010bRay et al 2011;Cramer et al 2012) and for reconstruction of the tectonomagmatic environments in volcanic source areas (Batchelor 2009;Hetherington et al 2011). Various methods for such fingerprinting exist, and the composition of magmatic phenocrysts apatite (Batchelor et al 1995;Ray 2007;Sell & Samson 2011), biotite (Batchelor 2003) and sanidine (Kiipli & Kallaste 2002) and trace element characteristics (Batchelor & Jeppson 1999;Batchelor & Evans 2000;Huff et al 2000;Inanli et al 2009;Kiipli et al 2008b) have all been used for characterisation and interpretation of ash beds.…”

The Geniai Tuff in the southern East Baltic area - a new correlation tool near the Aeronian/Telychian stage boundary, Llandovery, Silurian

“…Many Silurian bentonites are recorded also in Early Palaeozoic sedimentary rocks in England (Ray 2007(Ray , 2011 and Scotland (Batchelor & Weir 1988). In the East Baltic area ash beds from a total of 51 volcanic eruptions have been identified in the Telychian (Kiipli et al 2008a(Kiipli et al -c, 2010b) and 50 in the Wenlock (Kiipli et al 2010a). Ash beds in sedimentary sections carry valuable information about the geochemical type of volcanism and can be used as stratigraphical markers for precise correlation of sections.…”