The Schilfsandstein and its flora; arguments for a humid mid-Carnian episode?

Abstract

Recently intensified research on the mid-Carnian episode stimulated discussions about the mid-Carnian climate and a supposed humid climate shift. This basin-scale study on the Schilfsandstein, the type-example of the mid-Carnian episode, applied sedimentological, palynological and palaeobotanical proxies of the palaeoclimate to a large dataset of cored wells and outcrops. The results demonstrate the primary control of circum-Tethyan eustatic cycles on the Central European Basin where transgressions contributed to basin-scale facies shifts. The palaeoclimate proxies point to a uniform arid to semi-arid Carnian climate with low chemical weathering and high evaporation. Consequently, transgressions into the Central European Basin led to increased evaporation forcing the hydrological cycle. The increased runoff from source areas resulted in high-groundwater stages on lowlands characterized by hydromorphic palaeosols and intrazonal vegetation with hygrophytic elements. During lowstands, reduced evaporation and runoff led to increased drainage and desiccation of lowlands characterized by formation of vertisols, calcisols and gypsisols and zonal vegetation with xerophytic elements. The proposed model of sea-level control on the hydrological cycle integrates coeval and subsequent occurrences of wet and dry lowlands, hydromorphic and well-drained palaeosols, and intrazonal and zonal vegetations. Thus, the Schilfsandstein does not provide arguments for a humid mid-Carnian episode. Supplementary material: Datasets of Palynomorph Eco Group (PEG) and Macroplant Eco Group (MEG) analyses are available at https://doi.org/10.6084/m9.figshare.c.4182593

The Carnian pluvial episode (Late Triassic): new insights into this important time of global environmental and biological change

“…The age of this interval is constrained by sporomorph, choncostracan and vertebrate biostratigraphy. The sedimentary record comprises major riverine and floodplain deposits containing kaolinitic gleyed to spodic palaeosols and local coal beds, which testify to more humid conditions and are similar to those observed in other non-marine settings in Spain and Germany (Barrenechea et al 2018;Franz et al 2018 second part of the thematic set).…”

Extinction and dawn of the modern world in the Carnian (Late Triassic)

“…1 ). In many sedimentary successions, fossil soils that formed during the CPE reflect the increase in rainfall, where analysis indicates that they developed under more humid conditions than seen either before and after ( 2 , 35 , 36 ).…”

Palynology and weathering proxies reveal climatic fluctuations during the Carnian Pluvial Episode (CPE) (Late Triassic) from marine successions in the Transdanubian Range (western Hungary)

“…). Palaeoclimate proxies (e.g., low maturity Carnian sandstones, clay mineral profiles and paleosols indicative of high evaporation rates) do not point to a consistent climate change across European successions (e.g., Franz et al 2018). Some works suggest only minor climate change with a generally arid to semi-arid background climate (from the UK Baranyi et al 2018; from Spain Barrenechea et al 2018), while data from the Germanic Basin argue for a uniform arid to semi-arid Carnian climate (Visscher et al 1994).…”