A palynological study of the Ordovician to Devonian sediments of the Anti Atlas, Morocco Michael G. SnapeM. Sc. Submittedin partial fulfilment of the requirementsfor the degreeof Doctor of Philosophy Iti *a SjAksFF iL4ý-O Vol%- I TEXT BOUND INTO THE SPINE CONTAINS PULLOUTS Summary Approximately 300 field and well samplesfrom the Ordovicianto Devonianinterval of the Anti Atlas, Morocco havebeen preparedfor palynologicalinvestigation. Of these,118 were selectedfor detailed analysisbased on the quality of the palynologicalrecovery, an attemptto achievethe beststratigraphic coverageas possiblefrom the materialavailable and also basedon the presenceof macrofossildata. A rapid palynological preparation technique for observation by light microscopy has been developed to analyse thermally mature, brittle assemblages,such as those encountered. Reviewsof the Acritarcha, the fossil Prasinophytaand the Chitinozoaare presentedwith discussionof their morphology,biological affinity and classification. Taxa from thesegroups are treatedsystematically with 389 describedspecies recorded, assignable to 115genera. A total of 71 unpublishedforms are describedin opennomenclature. Miospores; have also beenrecorded to enhancebiostratigraphic resolution and environmentalinterpretation of the assemblagesstudied. The miosporetaxa recordedare illustratedwith their authorscited in the plate captions. Semi-quantitativeanalyses of the assemblageshas enabled the recognitionof 33 PalynologicalAssociations from the Ordovicianthrough Devonianbased on the presence,absence and abundanceof the tax&recorded. Cluster analysisof the sampleshas been undertaken to assistin the recognitionand to quantify the similarity of the assemblages.The Ordovicianfield samplesyielded poorly preservedassemblages from which 12 Associationsare recognised.The Silurian to Lower Devonianfield samplesyielded moderateto well preservedassemblages despite the high thermalgrade of the material. Twelve Associationsare defined from this interval, the agesof which are all highly constrainedby the generallyrich graptoliteassemblages. Nine Associationsare recognisedfrom the Devonianassemblages recovered from Well Oum Doul-I core samples. Theseassemblages are well preservedwith abundantand often diversemarine and terrestrial elementspresent. 'Me ageinterpretations of the 33 Associationsare basedon both macrofaunalevidence, when present,and on comparisonwith previouspalynological studies, primarily thosefrom Northern Gondwana. A generalpalaeoenvironmental, interpretation of the formationsstudied is attemptedfrom the semi quantitativeanalysis of the relative proportionsof environmentallysensitive palynomorph groups and the relative proportionsof morphotypeswithin palynomorph groups. The major bathymetricfluctuations in the environmentof depositionwhich are evident from the palynological,assemblages (e. g. the deepwater event in the early Silurian) are believedto be eustaticallycontrolled during the Ordovicianto Devonianin the Anti Atlas. The broad natureof the study, geographicallyand stratigraphically,has revealedmuch potential for future work, of both academicand commercialinterest, in the North African and Middle East region. Acknowledgments Simon PetroleumTechnology Ltd. are gratefully acknowledgedfor their funding of my scholarship. SeveralSPT personnelhave beenof great assistanceas the project evolved, namely Dr. J.P. G. Fenton, Mr. G. Wade, Dr. P.H. Swire, Prof. D. S. Wood, Dr. R. J. Davey, Dr. N. Butler and Mr. P. C. Hughes. Many peopleat my host institution are thankedfor their hospitality and friendship. I thank in particular my supervisorDr. E. G. Spinnerfor his guidance,and Prof. C. Downie, Dr. D. W. Jolley, Mr. D. McLean and Dr. M. Romanofor their valuable discussion. I also thank the technicalstaff Ms. D. Darwin, Mr. S.J. Ellin, Mr. P Higham and Mr. B. Piggot for their help. Prof. R. A. Spearsis gratefully acknowledged for the use of the departmentalfacilities. Thanks are extendedto Dr. T. P. Young for invaluablediscussion in the secondyear of the project and for the loan of his personalset of Moroccan geologicalmaps. Thanks also to Dr. R. B. Rickards for the days hospitality in Cambridgeon my visit to collect samplesfrom him. The last three and a half yearshave been made all the more enjoyablethanks to the companyof my colleaguesMr. N. M. Hogg and Mr. S.W. Smith. The week's 'fieldwork' in Teignmouthwill live long in the memory. Long may our friendshiplast. And to my parents,Mr. G.J. Snapeand Mrs. S.M. Snape,thank you both for your constantsupport. Contents Volume I Chapter 1. Introduction I Geographicsetting I Previouswork 4 Tectonicand palaeogeographicevolution 5 Lithostratigraphicframework 9 Chapter 2. Aims and objectives 22 Chapter 3. Techniques 23 Chapter 4. The Acritarcha 27 Introduction 27 Morphology 27 Biologicalaffinity 34 Classification 34 Systematics 38 GenusAcanthodiacrodium 38 GenusActinodissus 43 GenusActinophasis 45 GenusAmmon1dium 46 GenusArbusculidium 48 GenusBaltisphaeridium 49 GenusBaltisphaerosum 53 GenusBeudingisphaeridium 54 GenusCaldariola 55 GenusCandelasphaeridium 55 GenusComasphaeridium 56 GenusCoqphidium 57 GenusCrassiangulina 58 GenusCraterisphaeridium 59 GenusCrystallinium 60 GenusCýmatiogalea 60 GenusCýmbosphaeridium 64 GenusDacrylofusa 67 GenusDaillydium 68 GenusDasypilula 69 GenusDateriocradus 69 GenusDeflandrastrum 71 GenusDemorhethium 72 GenusDicrodiacrodium 73 GenusDictyotidlum 73 GenusDiexallophasis 76 GenusDuvernaysphaera 81 GenusEphelopalla 82 GenusFlorisphaeridium 83 GenusFrankea 84 GenusGoniosphaeridium 84 GenusGorgonisphaeridium 88 GenusHapsidopalla 91 GenusHeliosphaeridium 91 GenusImpluviculus 92 GenusLeiofusa 92 GenusLeiosphaeridia 94 GenusLeiovalia 95 GenusLophosphaeridium 96 Genus Maranhites 100 Genus Marrocanium 103 Genus Micrhystridium 105 Genus Mulliplicisphaeridium 105 Genus Muralicavia 112 Genus Navifusa 112 Genus Neoveryhachium 113 Genus Onondagella 114 Genus Oppilatala 115 Genus OrdoWcidium 117 Genus Orygmahapsis 117 Genus Ozotobrachion 118 Genus Palacanthus 119 Genus Peteinosphaeridium 119 Genus Pirea 120 Genus Polyedryxium 121 Genus Polygonium 122 Genus Pratulasphaera 124 Genus Quadraditum 125 Genus Quadrisporites M Genus Quisquilites 126 Genus Salopidium 127 Genus Solisphaeridium 127 Genus StelUchinatum 129 Genus Stelliferidium 130 Genus Stellinium 133 Genus Striatotheca 134 Genus Tetraporina 135 Genus 7hysanoprobolus 136 Genus Tongzia 137 Genus Trematophora 137 Genus Triangulina 138 Genus Trichosphaeridium 139 Genus Tunisphaeridium 139 Genus Tylotopalla 140 Genus Umbellasphaeridium 141 Genus Uncinisphaera 142 Genus Veliferiles 143 Genus Veryhachium 143 Genus Villosacapsula 154 Genus Virgatasporites 155 Genus Visbysphaera 156 Genus Vogilandia 159 Genus Vulcanisphaera 159 Genus Winwaloeusia 160 Acritarch Forms A-U 161 Chapter 5. The Prasinophyta 169 Introduction 169 Fossil prasinophyte morphology 169 Phycoma development 170 Classification 170 Systematics 172 Genus Cymatiosphaera 172 Genus Pterospermella 176 Genus Tasmanites 177 Chapter 6. The Chitinozoa 179 Introduction 179 Morphology 179 Biological affinity 182 Classification 184 Systematics 186 Genus Ancyrochitina 186 Genus Angochitina 191 Genus Armoricochitina 195 Genus Belonechitina 195 Genus Bursachitina 197 Genus Calpichitina 197 Genus Ongulochitina 199 Genus Conochitina 202 Genus Cyathochitina 203 Genus Desmochitina 206 Genus Eisenackitina 207 Genus Eremochitina 208 Genus Fungochitina 208 Genus Gotlandochitina 209 Genus Hoegisphaera 210 Genus JenAdnochitina 210 Genus Lagenochitina 211 Genus Margachitina 213 Genus Muscochifina 214 Genus Plectochitina 215 Genus Pogonochifina 216 Genus Pseudoclathrochilina 216 Genus Pterochitina 217 Genus Rhabdochitina 217 Genus Sagenachitina 218 Genus Sphaerochitina 219 Genus Urnochitina 220 Genus Velatachitina 220 Chitinozoan Form A 221 Chapter 7. Stratigraphic palynology 222 Ordovician field samples 225 Silurian to Lower Devonian field samples 238 Oum Doul-I core samples (Devonian) 251 Chapter 8. Environmental palynology 263 Chapter 9. Conclusions 274 Chapter 10. Further work 277 References 279 Appendix I. Ile samplesstudied 328 Appendix 111.The topographicmaps used 361 Appendix HI. The geologicalmaps used 363 VolumeH. Plates1-103 Volume III Plates104-200 L0ist of figures and enclosures. Figures. 1. Geographicmap of Morocco showingthe positionsof the topographicmaps utilised. 2 2. The physiographicregions of Morocco. 3 3. An early Ordovicianpalaeogeographic reconstruction of Northern Gondwana,from Paris 1990.6 4. Global palaeogeographicreconstructions for the latest Ordovician(Ashgill) and middle Silurian (Wenlock), from Scotese& McKerrow 1990. 7 S. Global palaeogeographicreconstructions for the early Devonian(Gedinnian) and late Devonian(Famennian), from Scotese& McKerrow 1990. 8 6. The lithostratigraphicframework for the OrdovicianSystem showing the comparison betweenthe publishedlithostratigraphy_ and that proposedby the RobertsonGroup in 1985. 11 7. The lithostratigraphicframework for the Silurian Systemshowing the comparison betweenthe publishedlithostratigraphy and that proposedby the RobertsonGroup in 1985. 14 8. The lithostratigraphicframework for the DevonianSystem showing the comparison betweenthe publishedlithostratigraphy and that proposedby the RobertsonGroup in 1985. 18 9. Palynologicalprocessing flowchart. 24 10. Acritarch morphology. 30 11. Acritarch morphology(continued). 32 12. Ile life cycle of Pterosperma. 171 . 13. Chitinozoanmorphology. 180 14. A comparisonof chitinozoanbiozonations from Northern Gondwanapublished