TY - JOUR AU - Gama, John AU - Schwark, Lorenz TI - Review of earliest Toarcian geological evolution in the East African Coastal Margin: Paleogeography, stratigraphy, and facies implications JF - JOURNAL OF AFRICAN EARTH SCIENCES J2 - J AFR EARTH SCI VL - 200 PY - 2023 PG - 18 SN - 1464-343X DO - 10.1016/j.jafrearsci.2023.104885 UR - https://m2.mtmt.hu/api/publication/33921453 ID - 33921453 N1 - Department of Organic and Isotope Geochemistry, Institute of Geosciences, University of Kiel, Germany Department of Petroleum Science and Engineering, University of Dar es Salaam, Tanzania WA-OIGC, School of Earth and Planetary Sciences, Curtin University, Perth, Australia Cited By :1 Export Date: 24 November 2023 Correspondence Address: Gama, J.; Department of Organic and Isotope Geochemistry, Germany; email: john.gama@ifg.uni-kiel.de AB - In the past decades, lower Toarcian strata have gained attention on a global paleogeographical scale but these strata have been poorly studied along the East African Margin. This study presents a comprehensive review of the Toarcian geological evolution of the East African Coastal Margin focusing mainly on the Mandawa Basin in Tanzania, the Morondava and Majunga Basins in Madagascar, the Lamu and Mandera Basins in Kenya, and the Luuq Mandera and Ahl-Mado Basins in Somalia. We discuss controversies in published reports regarding facies, stratigraphy, and pathways of marine ingressions during the Toarcian transgressive episode that led to the extension of a Neotethys sea arm (the Somali Ocean) into the East African Margin prior to the main phase of Gondwana drifting and the opening of the Indian Ocean.The earliest Toarcian transgressive phase was accompanied by rifting between East Africa and Madagascar, which most likely rejuvenated Karoo rifting, drove marine influxes and inundated existing depressional troughs in the Ahl-Mado, Luuq Mandera, SW Majunga, and Mandawa Basins. This resulted in the formation of the Arab-Indo-Madagascar embayment, a NNE-SSW striking epicontinental sea (Somali Ocean), which was linked to the Tethys Sea southward via the horn of Africa route, as well as in widespread deposition of Toarcian marine to coastal-lagoonal to continental sediments. The occurrence of major facies changes from predominantly conti-nental to shallow/marginal marine facies and the widespread distribution of an Arab-Indo-Madagascan Bou-leiceras ammonite association confirms the connection between the East African coastal sedimentary terrain and the Tethys Sea during the Toarcian. Influxes of marine waters from Tethys Sea were limited in extent to the rift -graben regions and reactivated Karoo faults system. Restricted marine deposition within a limited epicontinental sea likely ended during Late Aalenian-Bajocian times, when establishment of fully marine conditions began due to opening of the Indian Ocean. LA - English DB - MTMT ER - TY - JOUR AU - Whicher, John T. AU - Chandler, Robert B. AU - Hoffmann, Rene TI - Lytoceratid ammonites from the Inferior Oolite Formation (Middle Jurassic, Aalenian and Bajocian) of Dorset (United Kingdom) JF - PROCEEDINGS OF THE GEOLOGISTS ASSOCIATION J2 - P GEOLOGIST ASSOC VL - 134 PY - 2023 IS - 2 SP - 216 EP - 245 PG - 30 SN - 0016-7878 DO - 10.1016/j.pgeola.2023.03.001 UR - https://m2.mtmt.hu/api/publication/33921452 ID - 33921452 N1 - Export Date: 24 November 2023 Correspondence Address: Whicher, J.T.; Higher Marsh Farm, Marsh Lane, Somerset, United Kingdom; email: john@whicher.plus.com AB - Ammonites of the family Lytoceratidae from the Middle Jurassic Inferior Oolite Formation, Aalenian to lowermost Bathonian, of Dorset are rarely described, perhaps because the macroconchs are often very large and difficult to collect intact and the microconchs are very small and easily overlooked. Detailed stratigraphical collecting over several years has shown them to be a minor part of the ammonite fauna but more common at certain horizons. Four genera, Lytoceras, Megalytoceras Nannolytoceras and Pleurolytoceras have been shown to have different strat-igraphical ranges and abundances in the Aalenian and Bajocian but they have not been found in the Lower Bathonian of Dorset. The taxonomic basis of several of the well-known species is poorly described in the litera-ture and is remedied here. (c) 2023 The Geologists' Association. Published by Elsevier Ltd. All rights reserved. LA - English DB - MTMT ER - TY - JOUR AU - Hoffmann, R AU - Slattery, JS. AU - Kruta, I AU - Linzmeier, BJ. AU - Lemanis, RE. AU - Mironenko, A AU - Goolaerts, S AU - De Baets, K AU - Peterman, DJ. AU - Klug, C TI - Recent advances in heteromorph ammonoid palaeobiology JF - BIOLOGICAL REVIEWS J2 - BIOL REV VL - 96 PY - 2021 IS - 2 SP - 576 EP - 610 PG - 35 SN - 1464-7931 DO - 10.1111/brv.12669 UR - https://m2.mtmt.hu/api/publication/31829658 ID - 31829658 N1 - Funding Agency and Grant Number: RFBRRussian Foundation for Basic Research (RFBR) [18-05-01070]; BelspoBelgian Federal Science Policy Office [BR/175/A2/CHICXULUB]; DFGGerman Research Foundation (DFG)European Commission [DFG HO 4674/4-1]; Swiss National Science foundationsSwiss National Science Foundation (SNSF) [200020_169847, 200021_149119, 200020_169627]; Projekt DEAL Funding text: We are grateful to Alexander Lukeneder and two anonymous reviewers for constructive comments that significantly improved the quality of this review, and to John Welch and Alison Cooper for the handling of this manuscript. A.M. acknowledges financial support from RFBR grant no. 18-05-01070, the Russian amateur palaeontologists Marina and Andrei Belousko and Dmitry Vartanian for the donation of Ptychoceras specimens for this study, and Dmitry Vinogradov for permission to photograph specimens from his collection. S.G. received funding from the Belspo BR/175/A2/CHICXULUB project 'Chicxulub 2016 IODP-ICDP deep drilling: From cratering to mass-extinction'. J.S. acknowledges Garett M. Brown, Peter J. Harries, Keith P. Minor, Neil H. Landman, and Ashley L. Sandness. R.H. is grateful to Kevin Stevens for helpful comments on an early draft, Phyllis Mono for help with formatting, Gernot Nehrke for the Raman images shown in Fig. 2, and M. Rogov for helping us to find the originator of the term 'heteromorph'. Images of injured specimens were provided by Sonke Simonsen for Aegocricoeras raricostatum, Wolfgang Grulke for Pictetia, Kurt Wiedenroth for Aegocrioceras. R.H. thanks the DFG for financial support of this project (DFG HO 4674/4-1). C.K. received financial support from the Swiss National Science foundations (project nr. 200020_169847, 200021_149119, and 200020_169627). Open access funding enabled and organized by Projekt DEAL. Open access funding enabled and organized by Projekt DEAL. LA - English DB - MTMT ER - TY - JOUR AU - Pavia, Giulio AU - Fernandez-Lopez, Sixto R. TI - BAJOCIAN LISSOCERATINAE (HAPLOCERATOIDEA, AMMONITIDA) FROM THE MEDITERRANEAN-CAUCASIAN SUBREALM JF - RIVISTA ITALIANA DI PALEONTOLOGIA E STRATIGRAFIA J2 - RIV IT PALEON STRATIG VL - 125 PY - 2019 IS - 1 SP - 29 EP - 75 PG - 47 SN - 0035-6883 DO - 10.13130/2039-4942/11058 UR - https://m2.mtmt.hu/api/publication/31090820 ID - 31090820 N1 - Cited By :4 Export Date: 16 June 2023 Correspondence Address: Pavia, G.; Dipartimento di Scienze della Terra, Via Valperga Caluso 35, Italy; email: giulio.pavia@unito.it AB - A revision of the Bajocian Lissoceratinae is presented. The study of more than 500 lissoceratins from different sites of the Western Tethys (Northwest European, Sub-Mediterranean and Mediterranean bioprovinces) within the Tethys-Panthalassa Realm provided data useful to implement the systematics of these almost neglected, never deeply analysed ammonites. Two genera, Lissoceras Bayle and Semilissoceras n. gen., are described with 16 species, among which eight new species (four dimorphic, three macroconchiate and one microconchiate): L. submediterraneum, L. maizetense, L. ovale, L. sturanii, L. maerteni, S. ellipticum, S. turgidulum and S. costellatum. The neotype of L. oolithicum is established. The microconchiate genus Microlissoceras is regarded as the junior synonym of the macroconchiate Lissoceras. Taxa are discussed according to four groups that gather taxa sharing common morpho-structural features. They roughly relate to successive biochronostratigraphical intervals within the Bajocian Stage and are headed by species largely known in literature: S. semicostulatum (Buckman) with suboval to compressed whorl section and rectiradiate ribs on the outer half flank; L. oolitbicum (d'Orbigny) with subtriangular to ovate whorl section, large and depressed ventral saddle, large suspensive lobe; L. baugi Sturani with ovate to globular whorl section, narrow lobe E and suspensive lobe; and L. psilodiscus (Schloenbach) with highly compressed whorl section, high ventral saddle and narrow lobe E. The phyletic relation of Lissoceras and Semilissoceras to the Aalenian-Bajocian Bradfordia-group is discussed, regarding Semilissoceras as the known stem-taxon of the subfamily Lissoceratinae. LA - English DB - MTMT ER -