Foraminiferal record of the Middle Miocene climate transition prior to the Badenian salinity crisis in the Polish Carpathian Foredeep Basin (Central Paratethys)

Abstract

Foraminifers oc cur ring in marls un der ly ing the Mid dle Mio cene Badenian gyp sum in the north ern Pol ish Carpathian Foredeep in one bore hole sec tion [M³yny (Busko) PIG 1] and in two dewatering pits in op er at ing quar ries (Leszcze and Borków) con tain well-pre served foraminifers. Sixty-seven spe cies of ben thic and twenty-one spe cies of plank tonic foraminifers are re corded in the 12-m-thick sec tion of the M³yny bore hole. Ben thic as sem blages are char ac ter ized by the dom i nance of Bulimina and Uvigerina while plank tonic as sem blages are com posed mainly by warm-wa ter orbulinids and Globigerinoides spp. in the lower part of the M³yny sec tion and by tem per ate-cold wa ter Globigerina spp. in the up per part of the M³yny sec tion as well as the Leszcze and Borków sec tions. The tax o nomic com po si tion of foraminiferal as sem blages makes it pos si ble to dis tin guish two foraminiferal zones in the M³yny bore hole: the Orbulina suturalis and Uvigerina costai zones, and only the lat ter zone is ac ces si ble at Leszcze and Borków. The ben thic foraminiferal suc ces sions in the stud ied inter val sug gest ox y gen a tion and pro duc tiv ity changes in the Carpathian Foredeep Ba sin prior to the Badenian sa lin ity cri sis. Four in ter vals of low ered ox y gen a tion and/or el e vated or ganic flux to the sea-floor are rec og nized; the in ter vals in which foraminiferal as sem blages sug gest ma rine en vi ron ments with low ered ox y gen a tion in bot tom wa ters al ter nate be tween the in ter vals where stress mark ers form less than 50% of the ben thic foraminiferal as sem blages. Ben thic as sem blages are moder ately to highly di ver si fied, and spe cies have more equal fre quen cies. The upsection de crease in the pro por tion of planktonic foraminifers re flects the shallowing of the ba sin ac com pa nied by a de crease in the tem per a ture gra di ent be tween the up per (warmer) and deeper (colder) wa ter beds. The av er age palaeotemperature of wa ter based on d18 O of Uvigerina and Globigerina de creased by ca. 2 and ca. 6°C, re spec tively (from 9.9 and 17.4°C in the Orbulina suturalis Zone to 7.9 and 11.5°C in the Uvigerina costai Zone, re spec tively). Be low the gyp sum, the d 18 O val ues of both ben thic and plank tonic foraminifers show quite large vari a tions pos si bly due to the sa lin ity in crease. Co eval dom i na tion of ben thic foraminiferal assem blages by Bulimina sug gests in creased sur face wa ter pro duc tiv ity and an in creased or ganic flux to the sea-floor prior to the on set of evaporite de po si tion and/or sa lin ity in crease.

Timing of Langhian bioevents in the Carpathian Foredeep and northern Pannonian Basin in relation to oceanographic, tectonic and climatic processes

“…Orbulinas are the most widely dis trib uted in dex microfossils in this time in ter val, which oc cur in all Cen tral Paratethys bas ins (e.g., AEoriae et al, 2004AEoriae et al, , 2009Tomanová-Petrová and Švábenická, 2007;Spezzaferri et al, 2009;Selmeczi et al, 2012;de Leeuw et al, 2013;Peryt, 2013;Doláková et al, 2014;Holcová et al, 2015a, b;Gozhyk et al, 2015;Rybár et al, 2015). The FO of Orbulina rep re sents the base of the lo cal biozone of Praeorbulina-Orbulina suturalis (Cicha et al, 1975).…”

Recostruction of the unusual Mid Miocene (Badenian) palaeoenvironment of the Carpathian Foredeep (Lomnice/Tišnov denudational relict, Czech Republic)

“…As in our re sults, Hohenegger et al (2008) de scribed an alter na tion of warm and cold in ter vals with a gen eral cool ing trend. Peryt (2013) also, in slightly youn ger strata, showed that com pa ra ble ox y gen a tion and pro duc tiv ity changes pre ceded the "Badenian sa lin ity cri sis" in the Pol ish part of the Carpathian Foredeep. Though the ma rine his tory fin ished ear lier in Moravia, and de po si tion of evaporites have not been re corded here, the im pact of cli ma tic changes pre ced ing the sa lin ity cri sis on the ma rine palaeoenvironment is very sim i lar in both ar eas of the Carpathian Foredeep.…”

Coiling direction in Middle Miocene globorotaliids (Foraminiferida) – a case study in the Paratethys (Upper Silesia Basin, Poland)

“…In the coastal part of the ba sin, these events has been ei ther ab sent (Gonera and Kulka, 1979;Peryt, 2013) or de tected in one of the bore holes, but no data on coil ing has been given (£uczkowska, 1964).…”