Synsedimentary brecciation in the Eifelian (Middle Devonian) Baltic Basin: sudden catastrophe or diagenetic collapse?

Abstract

The breccia occurs as 0.2-2.7 m thick individual beds. The brecciated successions are 0.6-20 m thick. Breccia is found in 11 stratigraphic positions (Fig. 3).The breccia consists of highly variable angular to sub-rounded carbonate and siliciclastic mudstone clasts ABSTRACT The Eifelian sedimentary record in the epeiric Baltic Basin contains an extensive brecciated interval known as the Narva Breccia. During recent decades, the origin of this breccia has been attributed to (1) palaeoseismicity, (2) extraterrestrial impact event or (3) diagenetic collapse. Our studies show the presence of two different breccia types that form 11 stratigraphic horizons and contain several laterally and stratigraphically unrelated breccias. The occurrence of Type-1 and Type-2 breccias, together with carbonate sabkha and carbonate inter-to supratidal tidal flat deposits on the basin margins, indicates synsedimentary brecciation formed in a sabkha environment. Type-2 breccia could also originate from wave-cycling loading.

Roundness and surface features of quartz grains in Middle Devonian deposits of the East Baltic and their palaeogeographical implications

“…Later detailed sedimentological and facies analyses of the Pärnu, Narva, and Gauja levels have been carried out and the coastline position and direction of currents have been established (Ponten & Plink-Björklund 2007;Tovmasyan et al 2008;Tänavsuu-Milkeviciene et al 2008). The spatial and temporal distribution pattern of the roundness of quartz particles contained in the studied Devonian sedimentary rocks revealed some clear trends in the Baltic basin and contributes to the estimation of basin evolution and the palaeogeographical situation.…”

“…In the lowermost part of the Vadja Fm. a layer of sedimentary breccia is distributed throughout the shallow Baltic basin (Tänavsuu-Milkeviciene et al 2008). The dolostone of the Vadja Fm.…”

Meteorite impact craters and possibly impact‐related structures in Estonia

“…The Narva Breccias belong to a mixed carbonate‐siliciclastic sequence of Eiphelian age (Middle Devonian). The breccias are distributed across the ancient shallow epeiric Baltic Basin, occupying an area of about 160,000 km 2 in the Baltic countries and adjacent areas of NW Russia and Belarus (Tänavsuu‐Milkeviciene et al. 2008).…”

“…Also, Masaitis (2002) hinted at approximately 0.1 mm sized angular quartz grains with two sets of PDF found in a drill‐core sample from NE Lithuania, but details of this find have not been published so far. A sedimentological study by Tänavsuu‐Milkeviciene et al. (2008) states that the Narva Breccias occur as individual 0.2–2.7 m thick beds.…”

“…The Narva Breccias belong to a mixed carbonate-siliciclastic sequence of Eiphelian age (Middle Devonian). The breccias are distributed across the ancient shallow epeiric Baltic Basin, occupying an area of about 160,000 km 2 in the Baltic countries and adjacent areas of NW Russia and Belarus (Ta¨navsuu-Milkeviciene et al 2008). Among other explanations for their origin (a slump caused by paleoseismic activity [Karajajute-Talimaa and Narbutas 1964]; brecciation by early diagenetic sulfate crystallization [Pasˇkevicˇius 1997]), a probable impact origin was proposed by Masaitis (2002).…”