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A reappraisal of the Carboniferous macrofloras of the Zonguldak – Amasra Coal Basin, north-western Turkey

2012; Institute of Geology Zagreb; Volume: 65; Issue: 3 Linguagem: Inglês

10.4154/gc.2012.19

1333-4875

Christopher J. Cleal, I.M. van Waveren,

Geology and Paleoclimatology Research

Pennsylvanian (late Carboniferous) coal-bearing deposits have been known in north-western Turkey in the vicinity of Zonguldak since the early 19 th century (SCHLEHAN, 1852; SPRATT, 1877), and there were a number of early studies on the stratigraphy, including the plant biostratigraphy, notably by ZEILLER (1896, 1899) and RALLI (1896).For many years, coal mining was on a relatively small scale and mainly by foreign companies, and it was not until the mines started to be nationalised in the mid-1930s (GÜNEY, 1967 that there was a marked expansion in geological studies (RALLI, 1933;HARTUNG, 1937;JONGMANS, 1939;GRANCY, 1939;ARNI, 1939); some background comments to these investigations can be found in WAGNER & VAN AMEROM (1995) andWAGNER (1997).Plant biostratigraphy played a pivotal role in these studies, with numerous published species lists and in some cases specimens illustrated.After the 1939-1945 war, interest in the palaeobotany of these coal-bearing beds was continued mainly by JONG-MANS (1955), and two of his students, EGEMEN (1958EGEMEN ( , 1959) ) and WAGNER (in STOCKMANS, 1962, p. 664, fig.6).WAGNER (1984) made some brief comments on the Turkish data in his seminal biostratigraphical analysis of Carboniferous Euramerican floras, and subsequently (in KEREY et al., 1986) he made a more in depth analysis and figured several plant fossils.The stratigraphical sequence in the Zonguldak -Amasra Coal Basin has potentially much significance.If, as suggested by WAGNER (in STOCKMANS, 1962), there is an essentially complete succession of Namurian and Westphalian strata here, it would potentially provide a key link between the successions of the Caucasus and Donets, and the rest of Variscan Euramerica (sensu CLEAL et al., 2010).Moreover, CLEAL et al., (2010, 2011) have suggested that the progressive breakdown in the coal swamp biome in Euramerica during Westphalian times may have been initiated in the easternmost part of the area and a better understanding of how the Zonguldak -Amasra coal-bearing succession relates biostratigraphically to neighbouring areas will clearly be critical to understanding this major change in biotas and habitat.This paper will review the available published data on the distribution of plant macrofossils in the Zonguldak -Amasra Coal Basin and discuss the implications for the stratigraphic age of these deposits. Ab sTRA CTThe Zonguldak -Amasra Coal Basin in north-western Turkey has Carboniferous terrestrial deposits ranging in age from Arnsbergian to late Asturian or possibly early Cantabrian.They yield macrofloras that allow detailed biostratigraphical correlations with sequences in Europe.These correlations suggest there are substantial gaps in the Zonguldak -Amasra succession, with middle to upper Namurian, upper Langsettian, Duckmantian and lower Asturian strata apparently being missing.This in turn suggests the area was subjected to significant tectonic instability during Pennsylvanian (late Carboniferous) times and that this might have been instrumental in initiating the progressive change in composition and eventual collapse of the coal swamp biome across Variscan Euramerica during Westphalian times.