Paläontologie-Stratigraphie

Forschungsprogramm "Studien im Kambrium"

Bereich A: Maximized biostratigraphic resolution in the Cambrian calibrated with sea-level fluctuations and their impact on the biotic composition as well as radiometric age determinations

Bereich B: Early and middle Cambrian metazoan biodiversity and fine-scale stratigraphy: aspects of the Cambrian Radiation Event and environmental controls on Cambrian continents

• apl. Prof. Dr. Gerd Geyer
• Dr. Stefan Höhn
• Dr. Volker von Seckendorff
• Prof. Per Ahlberg (Lund University)
• Prof. Olaf Elicki (TU Bergakademie Freiberg)
• Dr. Ed Landing (New York State Museum, Albany)
• Dr. Ulf Linnemann (Senckenberg Naturhistorische Sammlungen Dresden)
• Stefan Meier (Marktredwitz)
• Prof. John S. Peel (Uppsala University)
• Dr. Michael Streng (Uppsala University)
• Tony Vincent (Aberdeen)
• Dr. Fred Sundberg (Phoenix, AZ)
• Prof. Thomas Wotte (TU Bergakademie Freiberg)
• Prof. Dr. Anna Żylińska (Warsaw University)

Project duration: since 2012

Funded by research grants GE 549/21-1 and GE 549/22-1 of the Deutsche Forschungsgemeinschaft (DFG)

Summary:

The research project deals with a characterization of organisms and their assemblages as well as sedimentological criteria in various parts of the Cambrian continents in order to achieve a maximized bio- and chronostratigraphic resolution for the lower (Terreneuvian and Series 2) and middle Cambrian (Miaolingian) successions.

The research project’s objectives include description and partly revision of important fossils that contribute to an improved knowledge of the fine-scaled biostratigraphic framework and thus facies developments on important Cambrian continents; on calibrated changes in depositional environments related to facies changes and hiatuses; determination of data indicating change in depositional characters during the Cambrian Series 2 and the Miaolingian; and developments in the organismic world exemplified by major bilaterian fossil groups. The project provides important data for a better understanding of the transition from the explosive development of bilaterians in the so-called Cambrian Radiation Event to the normal situation of faunal evolution during the rest of the Phanerozoic and will contribute to understand in how far the immediate aftermath of the “Cambrian Explosion” is controlled by environmental changes and lithofacies shifts.

Consequently, the proposed project aims at: (i) a description of hitherto neglected major fossil groups (such as selected trilobites, brachiopods and mollusc) and (ii) taxonomic revision of significant trilobites from the major Cambrian areas, such as Baltica (Sweden, Poland), West Gondwana (Morocco, Spain, Germany, Israel), West Avalonia (Newfoundland, New Brunswick), Laurentia (Greenland, western Canada, northwestern U.S.A.), East Avalonia (Shropshire), Siberia and South China. The results are directly useful for (iii) corrected and refined correlation schemes for the Cambrian; (iv) reconstruction of phylogenetic pathways; (v) a corrected palaeogeographic reconstruction of the global situation during the early and middle Cambrian; (vi) a refined dating of environmental fluctuations and the resulting changes in depositional history; (vii) data on true diversity of the faunas; and (viii) particularly interesting biological aspects. It is also planned to transfer the new data and resulting modifications for existing data to the Paleobiology Database (https://paleobiodb.org) for further use in palaeoecological analyses and provide data to the Geobiodiversity Database as well.

Biostratigraphic schemes serve as regional standards and contribute to a global framework, but need to be successively anchored by radiometric age determinations. The recognition of regional and intercontinental continental hiatuses is crucial for the recognition of sea-level fluctuations and plate movements.

The research activities are primarily contributions to the global Cambrian subdivision project of the International Subcommission of Cambrian Stratigraphy. The series of research activities conform with current GSSP projects of the ISCS.

In total, more than 40 single projects were actively carried out, dealing with Cambrian rocks and fossils from Jordan, the Iran, Kyrgyzstan, northern Greenland, Morocco, Namibia, Sweden, Denmark, northern Germany, the eastern United States, eastern Canada, the Canadian Cordillera, England, Poland, South China, Saxony and the Franconian Forest in Bavaria. Several publications are global synopses without a specific regional focus.

Publications:

Bayet-Goll, A., Geyer, G. & Daraei, M. 2018. Tectonic and eustatic controls on the spatial distribution and stratigraphic architecture of late early Cambrian successions at the northern Gondwana margin: The siliciclastic-carbonate successions of the Lalun Formation in central Iran. Marine and Petroleum Geology 98: 199–228, doi:10.1016/j.marpetgeo.2018.08.002.

Bayet-Goll, A., Wilmsen, M., Geyer, G., Mahboubi, A. & Moussavi-Harami, R. 2014. Facies architecture, depositional environments and sequence stratigraphy of the Middle Cambrian Fasham and Deh-Sufiyan formations in the central Alborz, Iran. Facies 60: 815‒841, doi:10.1007/s10347-014-0401-9.

Elicki, O. & Geyer, G. 2013. The Cambrian trilobites of Jordan – taxonomy, systematic and stratigraphic significance. Acta Geologica Polonica 63 (1): 1–56.

Geyer, G. 2014. Cambrian rocks in the Franconian Forest prove shallow marine deposition during a shift from West Gondwanan to sub-Baltican position. SDGG 85: 178.

Geyer, G. 2015. Cambrian subdivisions’last chapter: examination of the Cambrian Stage 4 lower boundary candidates. Berichte des Instituts für Erdwissenschaften der K.-Franzens-Universität Graz 21: 128.

Geyer, G. 2015. Considerations on the Precambrian Phanerozoic and Ediacaran Cambrian boundary: a historic approach to an unresolvable dilemma. Berichte des Instituts für Erdwissenschaften der K.-Franzens-Universität Graz 21: 129.

Geyer, G. 2015. Exotic trilobites from the lower–middle Cambrian boundary interval in Morocco and their bearing on the Cambrian Series 3 lower boundary. Paläontologische Zeitschrift 89 (4): 749–781, doi:10.1007/s12542-014-0254-0

Geyer, G. 2016. Taxonomy of the ‘Micmacca’ group, new Cambrian Chengkouiidae (Trilobita) from Morocco, and their bearing on intercontinental correlation. Memoirs of the Association of Australasian Palaeontologists 49: 329–393.

Geyer, G. 2017. Final fanfare: an ultimate glance to the Lower-Middle Cambrian boundary dilemma. In: Mcllroy, D. (ed.): International Symposium on the Ediacaran–Cambrian Transition 2017. Abstract Volume: 33; St. John’s, Nfld.

Geyer, G. 2017. The world’s oldest trilobites? A new look to the earliest known trilobites from the Anti-Atlas of Morocco. In: Pärnaste, H. (ed.): 6^th International Conference on Trilobites and Their Relatives, Tallinn, Estonia, 2017. Abstracts: 18–19; Tallinn.

Geyer, G. 2017. Trilobites of the Galgenberg Member (Tannenknock Formation), middle Cambrian Stage 5, Franconian Forest, Germany: a paradigmatic lowermost middle Cambrian West Gondwanan fauna. Paläontologische Zeitschrift 91: 5–70, doi:10.1007/s12542-017-0339-7.

Geyer, G. 2018. A new enigmatic hyolith from the Cambrian of West Gondwana and its bearing on the systematics of hyoliths. Papers in Palaeontology 4 (1): 85–100.

Geyer, G. 2019. A comprehensive Cambrian correlation chart. Episodes 42 (4): 12 pp., doi:10.18814/epiiugs/2019/019026.

Geyer, G. 2019. The earliest known West Gondwanan trilobites from the Anti-Atlas of Morocco, with a revision of the Family Bigotinidae Hupé, 1953. Fossils and Strata, 64: 55–153.

Geyer, G. & Corbacho, J. 2015. The Burlingiidae (Trilobita): revised generic composition, stratigraphy, and the first species from the early Middle Cambrian of West Gondwana. GFF 137 (3): 212‒225, doi 10.1080/11035897.2015.1027266.

Geyer, G. & Landing, E. 2016. The Precambrian–Phanerozoic and Ediacaran–Cambrian boundaries: a historical approach to a dilemma. In: Brasier, A. T., McIlroy, D. & McLoughlin, N. (eds.): Earth System Evolution and Early Life: a Celebration of the Work of Martin Brasier. Geological Society, London, Special Publications 448, http://doi.org/10.1144/SP448.10.

Geyer, G. & Malinky, J.M. 2019. Helcionelloid molluscs and hyoliths from the Miaolingian (middle Cambrian) of the subsurface of the Delitzsch–Torgau–Doberlug Syncline, northern Saxony, Germany. Paläontologische Zeitschrift 93: 23 pp., doi:10.1007/s12542-019-00472-z.

Geyer, G. & Peel, J.S. 2017. Middle Cambrian trilobites from the Ekspedition Bræ Formation of North Greenland, with a reappraisal of the genus Elrathina. Journal of Paleontology 91 (2): 265–293.

Geyer, G. & Vincent, T. 2014. The Paradoxides puzzle resolved – the appearance of the oldest paradoxidines and its bearing on the Cambrian Series 3 lower boundary. Paläontologische Zeitschrift 89 (3): 335‒398, doi 10.1007/s12542-014-0225-5.

Geyer, G., Bayet-Goll, A., Wilmsen, M., Mahboubi, A. & Moussavi-Harami, R. 2014. Lithostratigraphic revision of the middle Cambrian (Series 3) and upper Cambrian (Furongian) in northern and central Iran. Newsletters on Stratigraphy 47 (1): 21‒59.

Geyer, G., Buschmann, B. & Elicki, O. 2013/2014. A new lowermost middle Cambrian (Series 3, Stage 5) faunule from Saxony (Germany) and its bearing on the tectonostratigraphic history of the Saxothuringian domain. Paläontologische Zeitschrift 88: 239–262, doi:10.1007/s12542-013-0195-z.

Geyer, G., Landing, E., Höhn, S., Linnemann, U., Meier, S., Servais, T., Wotte, T. & Herbig, H.-G. 2019. Revised Cambrian stratigraphy in the Franconian Forest (Frankenwald), Germany, reveals typical West Gondwana succession in the Saxothuringian Belt. Newsletters on Stratigraphy 54 (2): 377–433, doi:10.1127/nos/2019/0495.

Geyer, G., Nowicki, J., Żylińska, A. & Landing, E. 2019. Comment on: Álvaro, J. J., Esteve, J. & Zamora, S. 2019. Morphological assessment of the earliest paradoxidid trilobites (Cambrian Series 3) from Morocco and Spain [Geological Magazine]. Geological Magazine 156: 1691–1707, doi:10.1017/S0016756818000961.

Geyer, G., Peel, J.S., Streng, M., Voigt, S., Fischer, J. & Preuße, M. 2014. A remarkable Amgan (middle Cambrian, Stage 5) fauna from the Sauk Tanga, Madygen region, Kyrgyzstan. Bulletin of Geosciences (Prague) 89 (2): 375‒400.

Geyer, G., Valent, M. & Meier, S. 2019. Helcionelloids, stenothecoids and hyoliths from the Tannenknock Formation (traditional lower middle Stage 4/Wuliuan boundary interval) of the Franconian Forest, Germany. Paläontologische Zeitschrift 93: 207–253, doi:10.1007/s12542-018-0433-5.

Kemnitz, H., Ehling, B.-C., Elicki, O., Franzke, H.-J., Geyer, G., Linnemann, U., Leonhardt, D., Plessen, B., Rötzler, J., Rohrmüller, J., Romer, R. L., Tichomirowa, M. & Zedler, H. 2017. Proterozoikum–Silur in der Stratigraphischen Tabelle von Deutschland 2016 [Stratigraphic Table of Germany 2016: Proterozoic to Silurian.]. Zeitschrift der Deutschen Gesellschaft für Geowissenschaften 168: 423–446, doi:10.1127/zdgg/2017/0134.

Landing, E. & Geyer, G. 2016. Comment on “Terreneuvian small shelly faunas of east Yunnan (South China) and their biostratigraphic implications” by B. Yang et al. [Palaeogeography, Palaeoclimatology, Palaeoecology 398 (2014) 28–58]. Palaeogeogr. Palaeoclimatol. Palaeoecol. (2016), doi:10.1016/j.palaeo.2016.04.016.

Landing, E. & Geyer, G. 2019. An early Cambrian greenhouse climate.  RE: Overused “greenhouse climate” paradigm: consequence for ancient climate synthesis. Science Advances 4, eaar5690 (2018), letter.

Landing, E., Antcliffe, J.B., Geyer, G., Kouchinsky, A., Bowser, S.S. & Andreas, A. 2018. Early evolution of colonial animals (Ediacaran Evolutionary Radiation–Cambrian Evolutionary Radiation–Great Ordovician Biodiversification Interval). Earth-Science Reviews 178: 105–135, doi:10.1016/j.earscirev.2018.01.013.

Landing, E., Geyer, G. & Buatois, L. 2015. Demonstrated Long-Term Utility of the Basal Cambrian GSSP at Fortune Head, Eastern Newfoundland. Berichte des Instituts für Erdwissenschaften der K.-Franzens-Universität Graz 21: 218.

Landing, E., Geyer, G. & Buatois, L. 2017. 25 years of practical success of the basal Cambrian GSSP at Fortune Head, Eastern Newfoundland. In: Mcllroy, D. (ed.): International Symposium on the Ediacaran–Cambrian Transition 2017. Abstract Volume: 58; St. John’s, Nfld.

Landing, E., Geyer, G., Brasier, M.D. & Bowring, S.A. 2013. Base of global Cambrian Stage 2. Carbon isotope-biostratigraphic definition and correlation of the upper stage of the Terreneuvian Series. Proposal for the International Subcommission on Cambrian Stratigraphy, 51 pp.

Landing, E., Geyer, G., Brasier, M.D. & Bowring, S.A. 2013. Cambrian Evolutionary Radiation: Context, correlation, and chronostratigraphy—Overcoming deficiencies of the first appearance datum (FAD) concept. Earth-Science Reviews 123: 133–172.

Landing, E., Geyer, G., Brasier, M.D. & Bowring, S.A. 2013. Proposed base of global Cambrian Series 2 and Stage 3: A Carbon-isotope and biostratigraphic definition for the upper part of the traditional lower Cambrian. Proposal for the International Subcommission on Cambrian Stratigraphy, 55 pp.

Landing, E., Geyer, G., Buchwaldt, R. & Bowring, S.A.. 2014. Geochronology of the Middle Cambrian: A precise U-Pb zircon date from the German margin of West Gondwana. Geological Magazine 152 (1): 28‒40, doi 10.1017/S0016756814000119.

Landing, E., Kouchinsky, A., Westrop, S.R., Geyer, G., & Bowring, S.A. 2015. 10 m.y. evolutionary stasis of earliest Cambrian (Terreneuvian) mollusk-rich faunas and Cambrian evolutionary radiation correlations. GSA Annual Meeting 2015, Abstracts and Program, 47 (7): 27.

Landing, G., Myrow, P.M., Narbonne, G.M., Geyer, G., Buatois, L.A., Mángano, M.G., Alan Kauffman, A., Westrop, S.R., Kröger, B., Laing, B. & Gougeon, R. 2017. Ediacaran–Cambrian of Avalonian Eastern Newfoundland (Avalon, Burin, and Bonavista Peninsulas). International Symposium on the Ediacaran–Cambrian Transition, Field Trip 4. Open File NFLD/3323, Memorial University & Geological Survey of Canada and Labrador, St. John’s, Nfld., 169 pp.

Landing, E., Schmitz, M., Geyer, G. & Bowring, S. A. 2017. Precise U-Pb volcanic zircon dates show diachroneity of oldest Cambrian trilobites: Examples from the West Gondwana (southern Morocco) and Avalonia paleocontinents. In: Mcllroy, D. (ed.): International Symposium on the Ediacaran–Cambrian Transition 2017. Abstract Volume: 59; St. John’s, Nfld.

Linnemann, U., Ovtcharova, M., Schaltegger, U., Gärtner, A., Hautmann, M., Geyer, G., Vickers-Rich, P., Rich, T., Plessen, B., Hofmann, M., Zieger, J., Krause, R., Kriesfeld, L., & Smith, J. 2019. New high-resolution age data from the Ediacaran–Cambrian boundary indicate rapid, ecologically driven onset of the Cambrian explosion. Terra Nova 31: 49–58, doi:10.1111/ter.12368.

Malinky, J.M. & Geyer, G. 2019. Cambrian Hyolitha of Siberian, Baltican and Avalonian aspect in east Laurentian North America: taxonomy and palaeobiogeography. Alcheringa 43 (2): 171–203, doi:10.1080/03115518.2019.1567813.

Peel, J.S., Streng, M., Geyer, G., Kouchinsky, A. & Skovsted, C.B. 2016. Ovatoryctocara granulata assemblage (Cambrian Series 2–Series 3 boundary) of Løndal, North Greenland. Memoirs of the Association of Australasian Palaeontologists 49: 241–282.

Streng, M. & Geyer, G. 2019. Middle Cambrian Bradoriida (Arthropoda) from the Franconian Forest, Germany, with a review of the bradoriids described from West Gondwana and a revision of material from Baltica. Paläontologische Zeitschrift 93: 567–591, doi:10.1007/s12542-019-00448-z.

Sundberg, F.A., Fletcher, T.P., Geyer, G., Kruse, P.D., McCollum, L.B., Pegel, T.V., Żylińska, A. & Zhuravlev, A.Yu. 2016. International correlation of the lower-middle Cambrian (Series 2-3, Stage 4-5). Memoirs of the Association of Australasian Palaeontologists 49: 83–124.

Weidner, T., Geyer, G., Ebbestad, J. O. R. & von Seckendorff, V. 2015. Erratic boulders from Jutland, Denmark, feature an uppermost lower Cambrian fauna of the Lingulid Sandstone Member of Västergötland, Sweden. Bulletin of the Geological Society of Denmark 63: 59–86.

Zhang, X.L., Ahlberg, P., Babcock, L.E., Choi, D.K., Geyer, G., Gozalo, R., Hollingsworth, J.S., Li, G.X., Naimark, E.B., Pegel, T., Steiner, M., Wotte, T. & Zhang, Zh.F. 2015. Appearance of trilobites during the Cambrian Explosion: a discussion on the definition of the Cambrian Series 2 and Stage 3. Berichte des Instituts für Erdwissenschaften der K.-Franzens-Universität Graz 21: 425.

Zhang, X.L., Ahlberg, P., Babcock, L.E., Choi, D.K., Geyer, G., Gozalo, R., Hollingsworth, J.S., Li, G.X., Naimark, E.B., Pegel, T., Steiner, M., Wotte, T., Zhang, Zh.F. 2017. Challenges in defining the base of Cambrian Series 2 and Stage 3. Earth-Science Reviews 172: 124–139.

 

Organismal development, biostratigraphy and depositional environments in Mesozoic and Cenozoic rocks of northern Bavaria

• Prof. Dr. Gerd Geyer

Project duration: since 2011

In cooperation with the Bayerisches Landesamt für Umwelt, Hof

Summary:

The project aims to clarify special topics of Mesozoic and Cenozoic deposits of northern Bavaria that suffer from deficiencies in knowledge in such aspects as biostratigraphy and the development of organismal assemblages through time and space and deficiencies in the understanding of depositional environments. Particular emphasis is put on aspects of the Muschelkalk and Keuper in Unterfranken and Oberfranken. This is a long-term project in cooperation with the Bayerisches Landesamt für Umwelt to provide data for the preparation of geological maps and the formal stratigraphical scheme as well as for the Subkommision Perm–Trias of the Deutsche Stratigraphische Kommission.

Publications:

Freudenberger, W., Geyer, G. & Schröder, B. 2014. Der Buntsandstein im nördlichen Bayern (nordwestliches Franken, Bruchschollenland und Randfazies im Untergrund). In: Deutsche Stratigraphische Kommission (ed.): Stratigraphie von Deutschland XI. Buntsandstein. Schriftenreihe der Deutschen Gesellschaft für Geowissenschaften69: 547–582 („2013“).

Friedlein, V. & Geyer, G. (in press). 8.5. Eschenbach-Formation – trE. In: Deutsche Stratigraphische Kommission (ed.): Stratigraphie von Deutschland XII. Muschelkalk. Schriftenreihe der Deutschen Gesellschaft für Geowissenschaften; Hannover.

Friedlein, V. & Geyer, G. (in press). 8.6. Grafenwöhr-Formation – trGR. In: Deutsche Stratigraphische Kommission (ed.). Stratigraphie von Deutschland XII. Muschelkalk. Schriftenreihe der Deutschen Gesellschaft für Geowissenschaften; Hannover.

Geyer, G. & Busche, D. 2014. Die neogene Dürrnberg-Formation (neu) im nördlichen Franken und ihre Bedeutung für die morphologische Entwicklung und die Klimageschichte an der Haßberge- und Steigerwald-Stufe. Jahresberichte und Mitteilungen der oberrheinischen geologischen Vereinigung 96: 379–405.

Geyer, G. & Friedlein, V. (in press). 9.10. Die Randfazies des Muschelkalks in Bayern. In: Deutsche Stratigraphische Kommission (ed.). Stratigraphie von Deutschland XII. Muschelkalk. Schriftenreihe der Deutschen Gesellschaft für Geowissenschaften; Hannover.

Geyer, G. & Kelber, K.-P. 2017. Spinicaudata (“Conchostraca”, Crustacea) from the Middle Keuper (Upper Triassic) of the southern Germanic Basin, with a review of Carnian–Norian taxa and suggested biozones. Paläontologische Zeitschrift, doi 10.1007/s12542-017-0363-7.

Geyer, G. & Lorenz, J. 2014. Quo vadis Buntsandstein? Ungeahnte Fallstricke der Nomenklatur und Stratigraphie im Spessart. – Jahresberichte der Wetterauischen Gesellschaft für die gesamte Naturkunde zu Hanau, Themenband Spessart, 163-164: 33–73.

Geyer, G., Ernst, R., Freudenberger, W., Hagdorn, H., Kramm, E., Ockert, W., Schmitt, O. & Wilmsen, M. (in press). 9.9. Der Muschelkalks im westlichen Franken (Bayern) und Südthüringen. In: Deutsche Stratigraphische Kommission (ed.). Stratigraphie von Deutschland XII. Muschelkalk. Schriftenreihe der Deutschen Gesellschaft für Geowissenschaften; Hannover

Loth, G., Geyer, G., Hoffmann, U., Jobe, E., Lagally, U., Loth, R., Pürner, T., Weinig, H. & Rohrmüller, J. 2013.Geotope in Unterfranken. 197 pp. Augsburg (Bayerisches Landesamt für Umwelt).

Okrusch, M., Geyer, G. & Lorenz, J. 2011. Spessart. Sammlung Geologischer Führer 106: VIII+368 pp. Stuttgart (Borntraeger).

Early and middle Cambrian metazoan biodiversity and fine-scale stratigraphy: aspects of the Cambrian Radiation Event and environmental controls on Cambrian continents

• Prof. Dr. Gerd Geyer

Project duration: since 2016

Supported by the German Research Foundation (DFG)

Summary:

The research project’s objectives include description and partly revision of important fossils that contribute to a better knowledge of the fine-scaled biostratigraphic framework and thus the facies developments on important Cambrian continents during the Cambrian Series 2 and 3; on calibrated changes in depositional environments related to facies changes and hiatuses; determination of data indicating change in depositional characters during the Cambrian Stages 4 and 5; and developments in the organismic world exemplified by major bilaterian fossil groups. The proposed project will provide important data for a better understanding of the transition from the explosive development of bilaterians in the so-called Cambrian Radiation Event to the normal situation of faunal evolution during the rest of the Phanerozoic and will contribute to understand in how far the immediate aftermath of the “Cambrian Explosion” is controlled by environmental changes and lithofacies shifts.

Consequently, the proposed project aims at: (i) a description of hitherto neglected major fossil groups (such as selected trilobites, brachiopods and mollusks) and (ii) taxonomic revision of significant trilobites from the major Cambrian areas, such as Baltica (Sweden, Poland), West Gondwana (Morocco, Spain, Germany, Israel), West Avalonia (Newfoundland, New Brunswick), Laurentia (Greenland, western Canada, northwestern U.S.A.), East Avalonia (Shropshire), Siberia and South China. The results shall be directly useful for (iii) corrected and refined correlation schemes for the Cambrian Series 2 and 3 (Stages 3 through 6); (iv) reconstruction of phylogenetic pathways; (v) a corrected palaeogeographic reconstruction of the global situation during the early and middle Cambrian; (vi) a refined dating of environmental fluctuations and the resulting changes in depositional history; (vii) data on true diversity of the faunas; and (viii) particularly interesting biological aspects. It is also planned to transfer the new data and resulting modifications for existing data to the Paleobiology Database(https://paleobiodb.org) for further use in palaeoecological analyses and provide data to the Geobiodiversity Database as well.

Publications:

Geyer, G. 2017. A new enigmatic hyolith from the Cambrian of West Gondwana and its bearing on the systematics of hyoliths. Papers in Palaeontology 2017: 1–16.

Geyer, G. 2017. Trilobites of the Galgenberg Member (Tannenknock Formation), middle Cambrian Stage 5, Franconian Forest, Germany: a paradigmatic lowermost middle Cambrian West Gondwanan fauna. Paläontologische Zeitschrift 91: 5–70.

Kemnitz, H., Ehling, B.-C., Elicki, O., Franzke, H.-J., Geyer, G., Linnemann, U., Leonhardt, D., Plessen, B., Rötzler, J., Rohrmüller, J., Romer, R. L., Tichomirowa, M. & Zedler, H. 2018. Proterozoikum–Silur in der Stratigraphischen Tabelle von Deutschland 2016. SDGG.

Landing, G., Myrow, P.M., Narbonne, G.M., Geyer, G., Buatois, L.A., Mángano, M.G., Alan Kauffman, A., Westrop, S.R., Kröger, B., Laing, B. & Gougeon, R. 2017. Ediacaran–Cambrian of Avalonian Eastern Newfoundland (Avalon, Burin, and Bonavista Peninsulas). International Symposium on the Ediacaran–Cambrian Transition, Field Trip 4. Open File NFLD/3323, Memorial University & Geological Survey of Canada and Labrador, St. John’s, Nfld., 169 pp.

Zhang, X.L., Ahlberg, P., Babcock, L.E., Choi, D.K., Geyer, G., Gozalo, R., Hollingsworth, J.S., Li, G.X., Naimark, E.B., Pegel, T., Steiner, M., Wotte, T., Zhang, Zh.F. 2017. Challenges in defining the base of Cambrian Series 2 and Stage 3. Earth-Science Reviews 172: 124–139.