Holocene tufa in the Slovak Karst: facies, sedimentary environments and depositional history

Abstract

Sev eral tufa com plexes are known in the Slo vak Karst which is a typ i cal karst area of a tem per ate cli mate. This area is built of Me so zoic car bon ates, mainly Tri as sic in age. The karst sys tems drain car bon ate pla teaux and lead wa ter to resurgences located in val leys which are up to 300 m deep. Be low the resurgences there are Ho lo cene fos sil tufa de pos its that ex ceed 12 m in thick ness. The tufas in clude stromatolite, moss, phytoclastic, oncoidal, and intraclastic fa cies. Ex ten sive bar rages which once dammed the up per reaches of the streams were formed in nar row val leys. They are com posed pre dom i nantly of moss fa cies and stromatolites, with sub or di nate oncoidal and phytoclastic fa cies. Phytoclastic, oncoidal and intraclastic fa cies are dom i nant in dammed seg ments of streams, and in clude gas tro pod shells and char coal frag ments. Some small moss cushions are also de vel oped. Bar rages and dammed ar eas formed in a lon gi tu di nal flu vial depositional sys tem. Con versely, below resurgences lo cated on pla teau slopes tufas of a perched springline depositional sys tem were formed. These com prise de pos its of prograding cas cades con structed by moss, phytoclastic and stromatolitic fa cies. Pres ently, the tufas ana lysed are in ac tive. They stopped grow ing in the Late Ho lo cene time, af ter which there was abrupt in ci sion of the streams. This caused downcutting into Ho lo cene tufas, in some places reach ing Me so zoic bed rock. At pres ent tufa is be ing pre cip i tated from streams in all the sites stud ied.Key words: flu vial tufa, perched spingline tufa, ra dio car bon dat ing, Qua ter nary, Late Ho lo cene tufa de cline, Cen tral Carpathians.

Variations of fluvial tufa sub-environments in a tectonically active basin, Pleistocene Teruel Basin, NE Spain

“…Mosses have a wide range of tufa sub-environments in which they may appear, from calm palustrine zones to fast flowing stream areas (Pedley, Gradziński et al, 2013). Bryophytes usually appear in the uppermost part of cascades (associated barrages), in steps in low slope channels and sometimes also in pools and dammed areas, forming cushions (occasionally intercalated with phytoclasts) (Arenas et al, 2010b), in all cases, in illuminated areas of the tufa system.…”

“…dammed pools and palustrine areas), predominantly in local depressions within lobes, between bands of mosses (Gradziński et al, 2013), or in floodplains or barrage deposits (Vázquez-Urbez et al, 2012). Some of these quiet areas formed by obstacles or changes of relief that broke water flow, forming phytoclastic barrage rims and the core of barrages.…”

“…Phytoclasts are ubiquitous facies which can be deposited during slow water flows or even due to a reworking of macrophytes during events with higher water velocity (Gradziński et al, 2013). Breccias appear randomly in some areas within mudstone facies suggesting erosional events of the nearby Mesozoic hillsides.…”

“…Description: Framestones (phytoherms) of bryophytes commonly form thick wavy layers (1-6 cm), overlying other facies in small depressions (Gradziński et al, 2013).…”

Molluscan assemblages in Late Holocene tufa cones in the Pieniny Mountains (southern Poland)

“…The great est num ber of sites rep resent ing these de pos its cor re spond to this pe riod (e.g., Jäger and Ložek, 1968;Alexandrowicz, 1983;Pazdur et al, 1988a, b;Pen te cost, 1991Pen te cost, , 1995Alexandrowicz and Alexandrowicz, 1995;Füköh, 1995;Alexandrowicz, 1997Alexandrowicz, , 2004Alexandrowicz, , 2009Alexandrowicz, , 2010Meyrick and Preece, 2001;Gedda, 2001Gedda, , 2006Žák et al, 2002;Meyrick, 2002: Gradziñski et al, 2013.…”