Palaeoenvironments of the Middle-Late Mississippian Moscow Basin (Russia) from multiproxy study of palaeosols and palaeokarsts.

摘要: Abstract Numerous pedogenically altered subaerial exposure surfaces within Middle–Late Mississippian (Visean–Serpukhovian) shallow carbonates in the Moscow Basin attest to sea-level fluctuations and climate change. In total, fifteen palaeosols at seven stratigraphical levels from five open pits were described studied detail. They show both stratigraphic lateral soil type variability. The factors of major influence are substrate type, time (tectonics relief), climate. All polycyclic consist least two parts. lower unit (substrate), consisting mainly limestone, with siliciclastic deltaic palustrine beds, was different degrees by weathering/pedogenesis. Depending on climate, limestone transformed into calcrete or caliche. is capped a terrigeneous topclay which represents an individual palaeosol developed prior subsequent marine flooding. Indications gley conditions, as well presence coal, sphaerosiderite framboidal pyrite, indicate wet peat–swamp environment that was, however, periodically dry. calculated mean annual precipitation (MAP) based CIA-K proxy units shows characterized alternating periods aridity humidity, most humid conditions (~ 1250 mm) during middle Visean. same applied Late sediments Appalachian similar MAP range. High-amplitude Mikhailovian–Venevian boundary followed prolonged resulted development laterally extensive deep karst pedocomplex then bed. structure scale this unconformity comparable those Florida Everglades environment, modern marsh landscape. majority topclays smectitic, except for arid environments, dominated kaolinite palygorskite, respectively. Besides mineralogy, we also provide data regarding geochemistry, carbon isotopic composition carbonate, organic matter characteristics including solid state 13C NMR δ13C data, evidence vegetation types field observations SEM images.