The 12th Plant Taphonomy Meeting
Table of contents
CREBER, G.: Two unusual fossil Triassic tree species in the Petrified Forest
National Park, Arizona, USA
DE LA FUENTE, M., MARTÍN-CLOSAS, C. & GOMEZ, B.: Palynofacies in
the lacustrine delta of Uña (Lower Cretaceous, Iberian Ranges)
EDWARDS, D.: Pinnatiramosus, a Llandovery vascular plant?
HOFMANN, C.-C. & ZETTER, R.: Pollen and spore distribution in modern sedimentary environments of the Orinoco delta (Venezuela) -
an actuo-palaeobotanical investigation
KELBER, K.-P.: Preservation and taphonomy of charcoal from the Upper Triassic
of southern Germany
KVACEK, J.: Plant habitats of the Peruc Korycany Formation (Cenomanian, Czech
Republic, Central Europe)
POOLE, I., Van BERGEN, P. & SILMAN, M.: Taphonomic observations from a
tropical river system: Implications for fossil wood and propagule assemblages
Van BERGEN, P. & POOLE, I.: Accounting for the relative absence of epiphytes
and palms in fossil floras? - observations from the modern Peruvian Amazon Basin
Van KONIJNENBURG-Van CITTERT, J.H.A.: A new
Annalepis species from the Liassic of Bavaria and the taphonomic problems connected with the genus
CREBER, G.: Two unusual fossil Triassic tree species in the Petrified Forest National Park, Arizona, USA
DE LA FUENTE, M., MARTÍN-CLOSAS, C. & GOMEZ, B.: Palynofacies in the lacustrine delta of Uña (Lower Cretaceous, Iberian Ranges)
EDWARDS, D.: Pinnatiramosus, a Llandovery vascular plant?
HOFMANN, C.-C. & ZETTER, R.: Pollen and spore distribution in modern sedimentary environments of the Orinoco delta (Venezuela) - an actuo-palaeobotanical investigation
KELBER, K.-P.: Preservation and taphonomy of charcoal from the Upper Triassic of southern Germany
KVACEK, J.: Plant habitats of the Peruc Korycany Formation (Cenomanian, Czech Republic, Central Europe)
POOLE, I., Van BERGEN, P. & SILMAN, M.: Taphonomic observations from a tropical river system: Implications for fossil wood and propagule assemblages
Van BERGEN, P. & POOLE, I.: Accounting for the relative absence of epiphytes and palms in fossil floras? - observations from the modern Peruvian Amazon Basin
Van KONIJNENBURG-Van CITTERT, J.H.A.: A new Annalepis species from the Liassic of Bavaria and the taphonomic problems connected with the genus
Geology Department, Royal Holloway University of London, Egham, Surrey
Schilderia adamanica and Woodworthia arizonica are two of the tree species that grew in the Upper Triassic of what is now Arizona USA. Each has its own special features. The trunk anatomy of Schilderia is most unusual and also there is evidence of penetration of the wood by arthropods. The wood of Woodworthia has horizontal vascular traces which, in life, would have supplied epicormic buds on the trunk surface.
Our previous results showed that the Uña delta contained a monotypic taphofacies formed mainly by cheirolepidiaceous macroremains. Thus, fragmentary shoots of Frenelopsis associated with its male cones (Classostrobus) and rare remains of another conifer (Glenrosa) dominated the deltaic front and the crevasse-splay deposits of the lower deltaic plain. Macroremains were absent from other depositional environments in the deltaic plain. Gomez et al. (2001) concluded from their macroremain taphofacies analysis that the stream feeding the Uña delta was almost exclusively fed with cheirolepidiaceous remains which were supplied by stands of shrubs or trees living upstream, and probably forming low-diversity woodlands in the upper deltaic plain.
Additional data from palynofacies analysis has now enabled us to complete the picture. Two different palynofacies have been found in the Uña delta. Both are dominated by poorly preserved woody remains (poorly structured brown wood in the sense of Batten, 1996), which are in agreement with the general depositional environment, i.e. the deltaic context. The two palynofacies can be distinguished by secondary, but diagnostic, constituents. Palynofacies 1, which corresponds to lower deltaic plain deposits, contains abundant cuticles (up to 30 %) and palynomorphs (up to 20 %), the latter being mainly represented by schizaeaceous spores and tasmanitids (prasinophyte cysts). Other significant palynomorphs of this facies were matoniaceous spores and pollen of angiosperms. In contrast, palynofacies 2, belongs to the deltaic front lignites and is characterised by abundant amorphous organic matter (up to 60 %) and amber (up to 10 %). Rare palynomorphs of the palynofacies 2 almost exclusively belong to Classopollis as already noted by Gomez et al. (2001). The present results confirm our previous hypothesis that the Uña delta was almost exclusively fed by woody, cuticular and pollen remains, which Gomez et al. (2001) mainly attributed to Cheirolepidiaceae living in the upper deltaic plain. They shed, however, new light on the palaeoecology of the lower deltaic plain, which was extensively populated by herbaceous ferns (Schizaeaceae). Ponds in this part of the delta were temporarily eutrophic and allowed for the development of prasinophyte blooms.
BATTEN, D.J. 1996. Chapter 26A. Palynofacies and palaeoenvironmental interpretation. En: Jansonius, J. & McGregor, D.C. (ed.), Palynology: principles and applications, American Association of Stratigraphic Palynologists Foundation, vol. 3, 1011-1064.
GIERLOWSKI KORDESCH, E.; GOMEZ FERNANDEZ, J.C. & MELENDEZ, N. 1991. Carbonate and coal deposition in an alluvial-lacustrine setting: Lower Cretaceous (Weald) in the Iberian Range (East-Central Spain). En: Anadón, P.; Cabrera, Ll. y Kelts, K. Lacustrine Facies Analysis. I.A.S. Special Publications, 13, 111-127.
GOMEZ, B.; MARTÍN CLOSAS, C.; MEON, H.; THEVENARD, F. y BARALE, G. 2001. Plant taphonomy and palaeoecology in the lacustrine delta of Uña (Late Barremian, Iberian Ranges, Spain). Palaeogeogr., Palaeoclimatol., Palaeoecol., 170: 133-148.
KREBS, B. 1980. The search for mesozoic Mammals in Spain and Portugal. Mesozoic Vertebrate Life, 1, 23-25.
KREBS, B. 1993. Das Gebiss von Crusafontia (Eupantotheria, Mammalia) - Funde aus der Unter-Kreide von Galve und Uña (Spanien). Berliner Geowissenchaftliche Abhandlungen, (E), 9, 233-252.
MOHR, B.A.R. 1987. Mikrofloren aus Vertebraten-fürenden Unterkreide-Schichten bei Galve und Uña (Ostspanien). Berliner Geowissenschaftliche Abhandlungen, A (86), 69-85.
MOHR, B.A.R. 1989. New palynological information on the age and environment of the Late Jurassic and Early Cretaceous vertebrate localities of the Iberian Peninsula (eastern Spain and Portugal). Berliner Geowissenschaftliche Abhandlungen, A (106), 291-301.
The superb preservation achieved by charcolification enables exceptionally wood detail analysis, e.g. in revealing
uniseriate separate bordered pits and pit aperture characteristic in cross-field pits. So far as microscopically
scrutinized, all wood belongs to the genus Dadoxylon ENDLICHER. Growth rings in secondary wood indicate a degree of seasonality.
The charcolified wood remains, sourced from fire prone coniferopsid upland forests, suggest that
wildfire was an important environmental factor in germanotype Keuper ecosystems. Abundant quantities
of charcoal together with Semionotus bergeri and other fish remains from the Coburger Sandstein of
Ebelsbach (northern Bavaria) are interpreted as the result of a local catastrophic wildfire. Erosion after
wildfire might have induced nutrient flux into the water body. Then eutrophic processes have led to low
oxygen levels and triggered out massive fish kill.
A. Braided river assemblage (partly tidally influenced as documented by palynology) with prevailing lauroids: Myrtophyllum, Grevilleophyllum, and Platanus, B. Meandring river assemblage with ferns (Schizeaceae - Schizeopsis, Anemia, Gleicheniaceae, angiosperms Liriodendropsis, Debeya. C. Large river levee and floodplain assemblage with the cycad Microzamia gibba and prevailing angiosperms Platanus bohemica, Debeya coriacea, Myrtophyllum geinitzii, "Aralia" kowalewskiana, Diplostrobus stupeckyanus, D. Salt marsh assemblage with Frenelopsis alata, Eretmophyllum obtusum, Dammarites albens, Diospyros cretacea, E. Swamp assemblage with taxodiaceae conifers Cunninghamites lignitum, Quasisequoia crispa, Sequoia hetereophylla, F. Regression marsh assemblage with Sphenolepis pecinovenisi, Cunninghamites lignitum, Brachyphyllum squamosum, Nilssoniopteris pecinovensis, G. Unclassified upland vegetation, which is typical in presence of gymnosperms Zamites, Lindleycladus, Sagenopteris, Pinaceae and small leaved angiosperms (Dicotylophyllum sp.) Frenelopsis assemblage is typical for transgressive type of a coast with high level of underground water. The Sphenolepis assemblage is typical for regressive sediments with falling level of underground water. Representatives of Lauraceae are typical for disturbed habitats of braided rivers being in role of pioneers. The nutrient rich levee of large rivers bear the most diverse broad-leaved angiosperms (e.g in the locality Vysehorovice).
C12 C 13 analysis showed succession of the salt marsh. Frenelopsis was front plant growing most seaward, then Eretmophyllum
and Pseudoasterophyllites and an ngiosperm "Dispyros" cretacea.
All the assemblages show prevailing angiosperm taxa in river sediments and their shortage in sea influenced sediments and swamps.
Old Lower Cretaceous taxa were recorded in many habitats (Nilsonia from fluvial sediments, Nilssoniopteris from marsh),
but they are most prominent in specialised habitats of salt marshes (Frenelopsis, Eretmophyllum) and drier uplands
(Zamites, Lindleycladus, Sagenopteris).
The macromorphology of the new material will be discussed briefly, especially the apical extension preserved in one specimen which is about as long as the rest of the cone scale and very thin. The imprint material has been preserved in soft clays enabling the recovery of latex casts which demonstrate the epidermal structure and the presence of microspores in some of the specimens.
This genus presents a taphonomic problem in so far that up till now only sporophylls have been found and no vegetative parts of the plant, both in Annalepis zeilleri and in the new material. What can be the reason for this? Are the vegetative parts so delicate that fossilisation is virtually impossible? When we look at relatives that have also been found during mainly Triassic times, we see that members of the Pleuromeiaceae (to which Annalepis is often assigned) are much better known, and also Isoetalean macrofossils are well-known, often as whole plants, both from Triassic and Jurassic sediments. Even leaf cuticles have been recovered. Retallack (1997) included A. zeilleri in the genus Lepacyclotes Emmons because of the similarity of the sporophylls. Lepacyclotes is a lycopsid genus with leaves attached to a short lobed to rounded corm with fine adventitious roots. The ligulate leaves are arranged in a terminal cluster with most apical leaves modified to sporophylls. The megasporophylls more basally and the microsporophylls more apically placed. According to him, the foliage leaves are only few (and only present in the type species L. circularis) and therefore, have often been overlooked. But neither corm, nor sporophylls attached to some kind of structure have been preserved in Annalepis so far, and I do not believe that this attribution to Lepacyclotes based on similarity of sporophylls, can be maintained unless the whole plant has been recovered. And this leaves us again with the problem: why do we only have (numerous) sporophylls of these Annalepis species and no vegetative remains.
Ref.: Retallack, G.J., 1997. Earliest Triassic origin of Isoetes and quillwort evolutionary radiation. J. Paleont. 71(3): 500-521.
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