Microbially induced wrinkle structures in Middle Devonian siliciclastics from the Prague Basin, Czech Republic

Abstract

The occurrence of wrinkle structures in Middle Devonian deep‐water siliciclastic sequences of the Prague Basin (Roblín Member, Srbsko Formation, Givetian) is reported and interpreted to be microbially induced. Current and/or gravitational forces are considered the simplest explanation of the origin of these structures. Taking into account the tectonic activity linked with ongoing Variscan orogeny, the wrinkle structures could also be interpreted as soft sediment deformation structures originating due to exposure of mat‐bearing sediment to seismic shocks. The distribution of n‐alkanes and isoprenoids suggests two types of prevailing biological sources, namely phytoplankton, representing organic material from the water column, and benthic bacteria. Judging from the sedimentary facies and lack of petrographic characteristics suggestive of light competition, the microbial mats are interpreted to be formed by non‐autotrophic bacteria.

The interplay of environmental constraints and bioturbation on matground development along the marine depositional profile during the Ordovician Radiation

“…Observations of Ediacaran deep‐water microbial mats emphasized that MISS preferably occur in thin‐bedded sandstone turbidites (Laflamme et al, 2012; Simonson & Carney, 1999). Similarly, extensive wrinkle structures have been recently documented in distal areas of deep‐marine turbidity systems from the Middle Devonian siliciclastics from the Prague Basin, Czech Republic (Vodrazkova et al, 2019), and the Oligocene deposits of the Silesian Nappe of the Polish Outer Carpathians (Leonowicz et al, 2021). However, thick sandstone beds deposited periodically by high‐density turbidity currents show evidence of opportunistic colonization with high abundance of postdepositional elements (e.g., Palaeophycus , Skolithos , Cylindrichnus , Gyrochorte , Nereites , Planolites , Protovirgularia ).…”

“…Independently of the age, the vast majority of modern and ancient microbial mats are attributed to phototrophic cyanobacteria, which developed in shallow water (Noffke et al, 1996, 2001), whereas current knowledge on deep‐water mats is still limited, albeit with more examples being increasingly recognized in recent years (e.g. Bailey et al, 2006; Buatois & Mángano, 2003; Buatois et al, 2009; Flood et al, 2014; Heijs et al, 2005; Laflamme et al, 2012; Leonowicz et al, 2021; Pazos et al, 2015; Simonson & Carney, 1999; Vodrazkova et al, 2019). These recent developments are in line with current observations from both modern and ancient microbial mats of various environments suggesting that MISS‐producing microorganisms are not facies‐dependent, being instead found in any environment where the optimum ecological and taphonomic conditions are attained (e.g.…”

Biogenicity of amorphous organic matter and bacteriomorph acritarchs preserved in wrinkle structures from the Ediacaran Cíjara Formation, Spain

“…(C) Preservation of wrinkle structures as hyporeliefs and epireliefs; scale bar = 2–4 mm. (D) Reconstruction of sand grains and composite mat fragments rolling on wrinkle structures, and their preservation within them (modified from Mariotti et al., 2014; Vodrážková et al., 2018); scale bar = 2–4 mm.…”

First discovery of Mississippian trace fossils in the Świebodzice Unit from the Witoszów region (SW Poland)

“…MISS are in ter preted as matgrounds, which in volved sub strate mod i fi ca tion by mi cro bial ac tiv ity (Noffke et al, 2001(Noffke et al, , 2006Marriott et al, 2013;Pazos et al, 2015a;Vodrážková et al, 2019). Ac cord ing to Noffke et al (2001) mi cro bial mats do m i nated by cyanobacteria de pend on pho to syn the sis.…”

“…Accord ing to Davies et al (2016), most of the fos sil mi cro bial mats have been re ported from tidal and storm-in flu enced set tings, and only spo rad i cally from deeper wa ter fa cies. Vodrážková et al (2019) de scribed microbially in duced sed i men tary struc tures from the Mid dle De vo nian deep-wa ter siliciclastic se quences of the Prague Ba sin and con sider the or i gin of these struc tures as an effect of cur rent and/or grav i ta tional forces or of seis mic shocks.…”