Record of the Carnian Pluvial Episode in the Polish microflora
Introduction
Since the seminal works of Simms and Ruffell (1989, 1990), the “Carnian Pluvial Episode” (CPE), known also as the “Carnian Pluvial Phase” or “Carnian Pluvial Event” (for complete lists of names of this event see Ruffell et al., 2015; Mueller et al., 2016a and Dal Corso et al., 2018a) is still in the limelight of scientists studying the Late Triassic climate and evolution of continental palaeoenvironments (e.g., Dal Corso et al., 2018c). This short-lasting climatic change (late Julian–early Tuvalian, with a time span of approximately 5 Myr) is documented world-wide and connected with emplacement and subsequent activity of the Wrangellia Large Igneous Province (Furin et al., 2006; Dal Corso et al., 2012; Ruffell et al., 2015). It is also one of the best documented global climatic changes during the Triassic period (Kozur and Bachmann, 2010; Ogg, 2015; Dal Corso et al., 2018c) recognized in the Tethyan and Boreal realms (Fig. 1A). However, some authors reject the importance of climatic factors on the development of CPE, and explain observable changes in lithology as well as macro- and microflora of the Grabfeld and Stuttgart formations by eustatically controlled fluctuations of the groundwater table (see Visscher and Van der Zwan, 1981; Visscher et al., 1994; Franz et al., 2014, 2019).
In Poland, the CPE is poorly documented and was inferred mostly from palynological data (Orłowska-Zwolińska, 1983; Fijałkowska-Mader, 2015). Pluvialization of climate during the deposition of the Stuttgart Formation in the Upper Silesia (southern Poland) has also been suggested by Fijałkowska-Mader et al. (2015), Szulc et al. (2015b), and Jewuła et al. (2019), based on combined petrological, sedimentological and palynological proxies.
This paper, being a continuation of the above-mentioned studies, provides evidence of miospore spectra changes from the Grabfeld and Stuttgart formations, and along with statistical and sedimentological data from various parts of the Polish segment of CEB, supports the humidification of climate in the late Julian.
Section snippets
Abbreviations
a – Aulisporites astigomosus assemblage zone; CEB – Central European Basin; CPE – Carnian Pluvial Episode; lv – Triadispora verrucata subzone; PCA – Principal Component Analysis; QS-PA – Quantitative Spore-Pollen Analysis; SEG – Sporomorph Ecogroup.
Geological settings
During the Middle and Late Triassic epochs Poland was located in the eastern and south-eastern part of a large, epicontinental CEB, located above 30°N (Fig. 1A, Nawrocki et al., 2015), which was temporarily connected with the Tethys realm via Silesian-Moravian and East Carpathian gates (Fig. 1B).
Lithostratigraphy of the upper Triassic strata is well established in the German part of the CEB (see Beutler et al., 2005; Franz et al., 2014, 2018 for details; and Fig. 2), whereas in Poland most
Material and methods
Quantitative spore-pollen analysis (QS-PA) and PCA have been carried out on 37 miospore assemblages from 50 samples collected from Grabfeld and Stuttgart formations. These formations have been identified in 15 boreholes from the Polish Basin (Fig. 1). Depths of analyzed samples are given in the Appendices B and C.
QS-PA was performed on the slide collections stored in the Geological Museum (Warszawa) and in the Holy Cross Branch of the Polish Geological Institute-National Research Institute in
QS-PA and SEG model
Triadispora verrucata subzone is strongly dominated by pollen grains (Figs. 4, 5), representing mainly xerophytic conifer pollen Ovalipollis (Fig. 5, H group; Fig. 6I–K) and Triadispora (Fig. 5, N group; Fig. 6M–Q) of the voltziaceous affinity. Less frequently occur the cheirolepidiacean circumpollen Duplicisporites (Fig. 6R), Partitisporites (Fig. 6S) and Praecirculina (Fig. 5, S group), striatite pollen Lunatisporites (Fig. 6H), Striatoabietites (Fig. 6G) and Infernopollenites (Fig. 5, M
Discussion
Analyzed microflora assemblages more or less correspond to the palynomorph associations proposed by Franz et al. (2019). While the microflora of the T. verrucata subzone (Grabfeld Formation), corresponding to the Ovalipollis association, is relatively homogenous, the younger microflora of the A. astigmosus zone shows greater variation. In contrast to the German part of the CEB, palynomorph assemblages from the Neubrandenburg member in Poland generally do not contain aquatic forms. Single green
Conclusions
- (1)
Results of the palynostratigraphical analysis were proved to be significant for the stratigraphy of the relatively poorly recognized Stuttgart Formation in Poland and allowed for better correlations between the Polish and German part of CEB.
- (2)
This research confirmed the usefulness of the Principal Component Analysis (PCA) for determination of the mother plants’ environmental and partly climatic preferences. Based on the PCA analysis the Porcellispora spp. has been determined as xerophytic form
Acknowledgments
The authors acknowledge partial funding by the Polish Geological Institute-National Research Institute project number 61.2901.1501.00.0 and PRELUDIUM Grant to Karol Jewuła by National Science Centre, Poland (2018/29/N/ST10/02028). Authors thank the reviewers: Evelyn Kustascher and Wolfram M. Kürschner for their insightful comments. We would like to thank Si-Wei Chen for editorial assistance. We would like to thank Daisy Lee, Tim Sheehy and Natalia Wasielka (Durham University) for reading the
References (143)
- et al.
The Carnian Pluvial Event in western Europe: New data from Iberia and correlation with the western Neotethys and eastern North America-NW Africa regions
Earth-Science Reviews
(2014) - et al.
Carbon isotope records reveal synchronicity between carbon cycle perturbation and the “Carnian Pluvial Event” in the Tethys realm (Late Triassic)
Global Planetary Change
(2015) - et al.
Eustatic control on epicontinental basins: The example of the Stuttgart Formation in the central European Basin (Middle Keuper, Late Triassic)
Global Planetary Change
(2014) - et al.
Analysis of lomg term water quality changes in the Kis-Balaton Water Protection System with time series, cluster analysis and Wilks’ lambda distribution
Ecological Engineering
(2011) - et al.
A Tethys-wide mid-Carnian (Upper Triassic) carbonate productivity crisis: Evidence for the Alpine rheingraben event from Spiti (Indian Himalaya)
Journal of Asian Earth Sciences
(2007) - et al.
Late Triassic development of playa-gilgai environments from Upper Silesia (southern Poland)
Sedimentary Geology
(2019) - et al.
Synchronized changes in shallow water carbonate production during the Carnian Pluvial Episode (Late Triassic) throughout Tethys
Global and Planetary Change
(2020) - et al.
Equisetites arenaceus from the Upper Triassic of Germany with evidence for reproductive strategies
Review of Palaeobotany and Palynology
(1998) - et al.
New paleontological evidence of the Carnian strata in the Mežica area (Karavanke Mts., Slovenia): conodont data for the Carnian Pluvial Event
Palaeogeography, Palaeoclimatology, Palaeoecology
(2010) - et al.
The Middle Carnian Wet Intermezzo of the Stuttgart Formation (Schilfsandstein), German Basin
Palaeogeography, Palaeoclimatology, Palaeoecology
(2010)