Late Oligocene macrofloras from fluviatile siliciclastic facies of the Köln Formation at the south-eastern border of the Lower Rhine Embayment (North Rhine-Westphalia, Germany)

Abstract

Abstract The leaf remains described herein came from the oldest sites of the Cainozoic deposits in the Lower Rhine Embayment, located in the Siebengebirge Volcanic Field at the south-eastern border of this basin, in the area of Siebengebirge and vicinity. These revisited floras are bound to pre-volcanic siliciclastic facies of the Siebengebirge Mts., interpreted as marginal facies of the Köln Formation. Chronostratigraphically they are assigned to the late Oligocene (Chattian). The described leaf remains are partially compressions with preserved epidermal anatomy, and therefore highly useful for systematic determination of leaf impressions recovered from other localities of siliciclastic facies. On account of the epidermal characteristics of leaf compressions varying in gross morphology, the previously determined taxa Quercus goepperti, Laurus phoeboides, and Persea speciosa all fall into the abundantly represented Eotrigonobalanus furcinervis. The siliciclastic deposits originated in coastal and flood plain areas within fluviatile environments of variable deposition energy. Remains of Taxodium dubium, Eotrigonobalanus furcinervis, Populus germanica, and Daphnogene cinnamomifolia dominate among the recovered fossils. The general aspects of this plant assemblage correspond, together with their sedimentary settings, to riparian forest vegetation with mesophytic elements.