The reddish carbonates of the Kriukai Formation are northwards gradually replaced by light grey glauconitic and bioclastic middle- and inner-ramp carbonates (Estonian Shelf facies
The overlying strata consist of gray-green silty calcareous shale in the middle part of the formation (2m thickness), which represent the shelf facies
, and constitute the condensed section (CS) of the third-order sequence DS1.
Present-day Estonia is situated within the shelf facies
belt and transitional zone (Livonian Tongue).
The major Ordovician faunal change in the shelf facies
at the Keila--Oandu transition is a well-known biotic crisis (Meidla et al.
The sedimentological characterization of the TST 1-4 suggests that progressive deepening from inner shelf swampy lagoonal facies (Amb 4) to proximal (Amb 1) and distal middle shelf facies
(Amb 3B) dominates up section.
1999, 2001, 2003) have shown that dolomitization associates with the regressive phases of the evolution of the Baltic Palaeobasin and is related to the restricted area of inner shelf facies
. Dolomitization has changed the primary composition of the sediments but relict lithological textures suggest its diagenetic origin.
The inner shelf facies
have an enhanced porosity due to transformation of calcite to dolomite and micritization of skeletal fragments.
The rocks exposed at the Ohesaare cliff mostly represent the open shelf facies
belt, but the upper part of the section, which formed during a considerable shallowing event (Hints et al.
It is related to the inner shelf facies
zone (Teedumae et al.
The Dzvenygorod Fm represents open shelf facies
conditions, as shown by the Dayia bohemica brachiopod, Calymene dnestroviana trilobite and Holacanthia socialis coral communities (all BA 3, the last one also BA 4).
The presence of coquina interbeds indicates that deposition proceeded in the inner part of the open shelf facies
zone (IIIa) by H.
The material was collected from the carbonate rocks of reef and reef-related shelf facies
. Several longitudinal and transverse sections were made from each tabulate corallum.