A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | R | S | T | U | V | W | X | Y | Z |

Kirjeldus

From Mens, K., & Pirrus, E. (1997):

The Tiskre Formation in the current use is interpreted as a unit containing the Tiskre beds (= Diplocraterion Sandstone) by Öpik (1933) or the Tiskre Formation by Männil (Männil 1958a) together with the Kakumägi beds (Scenella Zone) by Öpik (1933) or the Kakumägi Member of the Pirita Formation by Männil (Männil 1958a).

The Tiskre Formation is distributed in northern and western Estonia (Figs. 18, 19) where it overlies the Lükati Formation. The lower boundary is lithologically abrupt and marked by a change from argillaceous rocks to sandstones. Between Muraste and Aseri, lenses of Mickwitzia conglomerate occur at that level. Its type section is an exposure at the southern end of the Rannamõisa Cliff, 14 km west of Tallinn (Mens & Pirrus 1977). The formation is at its thickest (20 m) in the stratotype area.

The Tiskre Formation consists of light-coloured massive or thick-bedded sandstones with thin interbeds of greenish-grey argillaceous rocks (Photo 16). Within the outcrop belt the Tiskre Formation is divided into the Kakumägi (lower) and Rannamõisa (upper) members.

The Kakumägi Member is represented by poorly sorted sandstones with an admixture of clayey material. Conglomerate lenses within the sandy sequence are locally present. In the basal part, sandstones are often well cemented with dolomitic cement. Bedding is mostly lenticular, casts of mud cracks, slump-rolls and ripple marks are common.

The Rannamõisa Member consists of horizontally bedded winnowed fine-grained or very fine-grained sandstones with thin interlayers of argillaceous rocks. Glauconite is present. Ripple marks and convolute bedding occur throughout the member (Pirrus 1978).