Pfefferkorn, Hermann W

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Now showing 1 - 9 of 9
  • Publication
    A Late Devonian Isoetalean Lycopsid, Otzinachsonia Beerboweri, Gen. Et Sp. Nov., From North-Central Pennsylvania, USA
    (2005-07-01) Cressler, Walter L; Pfefferkorn, Hermann W
    Compressions and impressions of an isoetalean lycopsid, comprising lower portions of stems, lobed bases, attached rootlets, and rounded rootlet scars, discovered in Late Devonian (Famennian) rocks of Clinton County, north-central Pennsylvania, Appalachian Basin, USA, are here described as Otzinachsonia beerboweri, gen. et sp. nov. These specimens demonstrate unequivocally the existence of the isoetalean lobe-and-furrow rhizomorphic growth pattern as early as the Late Devonian. They were found in an Archaeopteris- and Rhacophyton-dominated flora at Red Hill, an outcrop of the Duncannon Member of the Catskill Formation. The fossils were found in a dark-gray to greenish-gray lenticular siltstone layer that has an average thickness of 1.0 m. This deposit is interpreted as a floodplain pond. The low-energy nature of the deposit and the fine preservation of the intact rootlets of the specimens imply little or no transport. The plants were probably growing along the edge of the floodplain pond with their lower portions submerged for at least part of the year.
  • Publication
    Marattia aganzhenensis sp. nov from the Lower Jurassic Daxigou Formation of Lanzhou, Gansu, China
    (2008-03-01) Yang, Shu; Wang, Jun; Pfefferkorn, Hermann W
    Marattia aganzhenensis sp. nov. from the Lower Jurassic Daxigou Formation of Lanzhou, Gansu, China, is the second species of Marattia known in fertile structure from China, in addition to Marattia asiatica. The new species demonstrates the variability of the genus through its distinct character states. This new species is distinguished by the absence of venuli recurrentes, the shorter synangia, exclusively monolete spores without surface ornamentation, and the low number of spores produced per sporangium.
  • Publication
    A Pre-Glacial, Warm-Temperate Floral Belt in Gondwana (Late Visean, Early Carboniferous)
    (2002-12-01) Iannuzzi, Roberto; Pfefferkorn, Hermann W
    Unusual fossil macrofloras from South America (Peru, Bolivia, Brazil), Africa (Niger), India, and Australia are distinctly different from both the Early and Late Carboniferous floras of Gondwana. These floras can be correlated with each other based on macrofloral and palynologic composition, and dated as Late Visean to earliest Serpukhovian through palynologic data from several floras and isotopic data from Australia. The floras are dominated by pteridosperm foliage and characterized by the occurrence of tree-lycopsids, and represent a warm-temperate, frost-free floral belt in Gondwana that reached from 30 8 to as far as 60 8 South that existed directly before the onset of the major episode of the Carboniferous glaciation. The plants lived during an interval of very warm climate as indicated by the width and extent of the floral belt, conditions that facilitated the migration of plants into this area from other parts of the globe. The term Paraca floral realm is redefined and extended to include all of these Late Visean-earliest Serpukhovian floras throughout Gondwana.
  • Publication
    An early Pennsylvanian Flora with Megalopteris and Noeggerathiales from west-central Illinois
    (1977) Leary, Richard L; Pfefferkorn, Hermann W
    The Spencer Farm Flora is a compression-impression flora of early Pennsylvanian age (Namurian B, or possibly Namurian C) from Brown County, west-central Illinois. The plant fossils occur in argillaceous siltstones and sandstones of the Caseyville Formation that were deposited in a ravine eroded in Mississippian carbonate rocks. The plant-bearing beds are the oldest deposits of Pennsylvanian age yet discovered in Illinois. They were formed before extensive Pennsylvanian coal swamps developed. The flora consist of 29 species and a few problematical forms. It represents an unusual biofacies, in which the generally rare genera Megalopteris, Lesleya, Palaeopteridium, and Lacoea are quite common. Noeggerathiales, which are seldom present in roof-shale floras, make up 20% of the specimens. The Spencer Farm Flora is and extrabasinal (="upland") flora that was growing on the calcareous soils in the vicinity of the ravine in which they were deposited. It is suggested here that Noeggerathiales may belong to the Progymnosperms and that Noeggerathialian cones might be derived from Archaeopteris-like fruitifications. The cone genus Lacoea is intermediate between Noeggerathiostrobus and Discinites in its morphology. Two new species, Lesleya cheimarosa and Rhodeopteridium phillipsii, are described, and Gulpenia limburgensis is reported from North America for the first time.
  • Publication
    Early Permian coal-forming floras preserved as compressions from the Wuda District (Inner Mongolia, China)
    (2007-01-02) Pfefferkorn, Hermann W; Wang, Jun
    Four different compression/impression floras are preserved in only 4.32 m of the geologic section in the Early Permian Shanxi Formation of the Wuda District of Inner Mongolia, northwestern China. These floras represent four different plant communities and landscapes that followed each other in time. The oldest flora was rooted in sandy clay and initiated peat accumulation that lead to the formation of the lower coal seam. This seam is 230-cm thick and overlain by a 66-cm thick volcanic tuff that preserves a second different flora that grew on the peat at the time of the ash-fall. Standing stems and large plant parts are present. The upper part of the tuff is rooted by a single species of lycopsid (the third flora) again initiating peat accumulation. On top of this second seam of 120 cm thickness rests a roof-shale, deposited as mud in a shallow lake, the formation of which was responsible for the cessation of peat deposition. This fourth flora represents the plants growing around the lake on clastic substrate. Four different environments followed each other in this locality over a geologically short time span and each time conditions prevailed to preserve plant macrofossils. Three of these floras represent peat-forming plant communities of essentially the same time interval. This demonstrates the great variability of vegetation and landscapes in the tropical Cathaysian realm of the Late Paleozoic.
  • Publication
    Reconstruction and architecture of medullosan pteridosperms (Pennsylvanian)
    (1984) Pfefferkorn, Hermann W; Gillespie, W. H; Resnick, D. A; Scheihing, M. H
    A new reconstruction of the architecture of medullosan pteridosperms is proposed on the basis of three stems preserved as compression-impression fossils: one from the Southern Anthracite Coal Field of Pennsylvania (lower part of Llewellyn Formation, Pennsylvania, Westphalian D) probably belonging to Alethopteris foliage; a second stem from the roof shale of the Eagle coal bed (Kanawha Formation, Middle Pennsylvanian, Westphalian B) of West Virginia, associated with Neuropteris foliage; and a third reported from the Stephanian of Commentry, France, in connection with Odontopteris foliage. The diameters of the Llewellyn, Eagle, and Commentry stems are 17 cm, 13 cm, and 6.5 cm, respectively. All three stems bear remnants of petioles up to several centimeters in length. The petolar remnants indicate that the living leaves grew upward at an angle of 30 - 60 degrees from the vertical, a growth habit that is common in present day tropical plants with similar overall architecture. Leaves drooped only when they were dying. After decay they broke off and left short petiolar remnants bent downward. The Llewellyn and Eagle stems represent plants with thick, straight stems, whereas the Commentry specimen shows a thin and slightly curved stem.
  • Publication
    Response Of Late Carboniferous And Early Permian Plant Communities To Climate Change
    (2001-05-01) DiMichele, William A; Pfefferkorn, Hermann W; Gastaldo, Robert A
    Late Carboniferous and Early Permian strata record the transition from a cold interval in Earth history, characterized by the repeated periods of glaciation and deglaciation of the southern pole, to a warm-climate interval. Consequently, this time period is the best available analogue to the Recent in which to study patterns of vegetational response, both to glacial-interglacial oscillation and to the appearance of warm climate. Carboniferous wetland ecosystems were dominated by spore-producing plants and early gymnospermous seed plants. Global climate changes, largely drying,forced vegetational changes, resulting in a change to a seed plant–dominated world, beginning first at high latitudes during the Carboniferous, reaching the tropics near the Permo-Carboniferous boundary. For most of this time plant assemblages were very conservative in their composition. Change in the dominant vegetation was generally a rapid process, which suggests that environmental thresholds were crossed, and involved little mixing of elements from the wet and dry floras.
  • Publication
    A New Species of Discinites (Noeggerathiales) Associated with a New Species of Yuania from the Lower Permian of Inner Mongolia, China
    (2004-11-01) Wang, Jun; Pfefferkorn, Hermann W; Feng, Zhuo; Shen, Guanglong
    A fructification Discinites baculiformis sp. nov. and the foliage Yuania wudensis sp. nov. are described from the lower Permian Shanxi Formation of Wuda, Inner Mongolia, North China. Discinites baculiformis sp. nov. is at least 31 cm long and 1.5–1.8 cm wide. It has more than 78 whorls of sporophylls, each with ca. 85 sporangia on the adaxial side, a total of more than 6630 sporangia. The impression of the sporophyll epidermis is preserved, and cells are visible. In situ trilete spores are detected. The new species represents the longest strobilus with the largest number of whorls of sporophyll disks so far known in the genus. Yuania wudensis sp. nov. has unbranched rachises, with alternate to subopposite elongate ellipsoidal pinnae. Epidermal cells are rectangular, long, and narrow. The two new species might represent the fructification and foliage of the same parent plant, since there is no other noeggerathialean member in the taphonomic plant community. The association is comparable with the association of Discinites and Russellites from the Permian of Texas.
  • Publication
    A comparison of the floras of the Colchester (No. 2) Coal and Francis Creek Shale
    (1970) Peppers, R. A; Pfefferkorn, Hermann W
    Abundant data from spore studies of the Colchester (no. 2) Coal Member and from investigations of plant compressions in the Francis Creek Shale provide an opportunity to compare the flora of the coal with that of the overlying shale in the northeastern part of the Illinois Basin. As both floras were investigated by different methods and since different systems of form genera were used, it is first necessary to review the plant taxa found in the 2 facies and to arrange them according to major plant groups. Paleoenvironmental interpretations of Pennsylvanian floras are rare and widely scattered in the literature; therefore some of the research on fossil spores and plant assemblages from other strata is discussed in this report. Finally, the report presents an interpretation of paleoecological conditions that existed during deposition of peat and mud, which eventually formed the No. 2 Coal and Francis Creek Shale.