Micropaleontology

1. Micropaleontology By Prof. Dr. Salah N. Ayyad

2. Introduction and the importance of microfossils Lecture 1

3. Thedefinitionof micropaleontology is the study of microscopic fossils that they must be examined with a microscope. • Most marine microfossils areprotists(unicellular plants and animals), but others aremulticellularormicroscopic partsof macroscopic forms. • Thevalueof marine microfossils is enhanced by their: • -minute size. • - abundant occurrence. • - wide geographic distribution in sediments of all ages. • - and in almost all marine environments. • Mostplanktonic and many benthicmicrofossils have wide geographic distributions that make them indispensable for regional correlations and comparisons, and paleooceanographic reconstructions.

4. Marine microfossils occur in sediments ofPrecambrian to Recentages, lived in almost all marine provinces;Neritic(littoral) province (inner, middle and outer) up to 200m,Bathyal(Oceanic) province (upper, middle and lower) up to 2000m and Abyssal(Oceanic) province up to 5000m.

6. Radiolarian Shells Silicoflagellate, Dictyocha Microfossils include: Radiolaria, silicoflagellates, calcareous nannoplankton, pteropods, foraminifera and diatomsare planktonic (free floating) and live in abundance from 0 to 200m in the open ocean.

7. Calcareous nannoplankton Pteropods

8. Planktonic Diatoms Planktonic Foraminifera Diatoms, radiolarians, and a silicoflagellate

9. Planktonic Foraminifera

10. ostracodes Crisia acropora Chorizopora brongniartii • Other groups as theostracodes, bryozoa, and some foraminifera and diatoms are benthic (adapted to living on the bottom of the sea). Bryozoa

11. Benthic Foraminifera

12. Benthic Foraminifera

13. Benthic marine diatoms

14. Some forms, such as thedinoflagellatesare known to contain both planktonic and benthic phases in their reproductive cycle and are useful tools inpaleoecology. • Spores and pollen, although derived from land plants, are strongly climate-dependent. • Thus, their presence and distribution patterns in near-shore marine sediments allow interpretations of continental climates; and/or, like chemical traces, their distribution can be used to monitor current movement.

16. Scope of Foraminiferal studies • The reason why Foraminifera are important - in oil exploration and - other subsurface work as index fossils (indicators of a particular geological age) lies not only in their abundance but equally in their range of size. • This is generally between 0.10 mm and 1.00 mm in diameter and averages about 0.33 mm, equal to the fine sand grade of sediments. • Although some are macroscopic and exceed 5.00 mm in diameter, "Larger Foraminifera", and some are smaller than 0.10 mm, "Micro foraminifera".

17. The reasons for the particular value of foraminifera in stratigraphy 1) They are abundant in mostmarine sediments, inouter-shelfmudswhere several thousand specimens representing some fifty species frequently occur in a 10 ml volume sample. According to Levine (1962) they constitute2.5%of the animalkingdom and more thanhalf the known protozoa. A number of species belonging to different families also occurinbrackish waterbut only members of the non-testateAllogromiidaoccur infreshwater. Therefore, the occurrence of Foraminifera is an indication of marine(high marine to brackish) conditions. 2) The average about0.33mmin diameter(fine sand )with rangefrom0.10mm to 1.00mm. This means thatthey escapedestruction during the ordinary process of rotary drilling.

18. 3) Stratigraphic markers "tops" based on the first appearance of species and assemblages in ditch cuttings can be applied in correlation which can be carried out without expensive coring. 4) It has existed in abundance since the Cambrian, showing well-marked evolutionary changes useful in stratigraphy. Different familiesmark the Eras and major time Periods. 5) Many species are planktonic and of worldwide occurrence. When this wide geographical range is combined with a short vertical time range they make excellent index fossils. 6) Many species are restricted in their habit and confined to a particular ecological niche. They are thus particularly useful in interpreting the character of ancient environments. 7) Foram-limestones (larger foraminifera) are well developed in the Upper Paleozoic, The Upper Cretaceous and in the Cenozoic. 8) Classification is based on characters shown by the fossilisable test.

19. Foraminifera • Scope of Foraminiferal studies. • Collection, Preparation and Examination (Technical methods). • The living Foraminifera. • Test morphology and composition. • Classification of the Foraminifera. • The Agglutinated Foraminifera. • The Fusulinida. • The Miliolida. • The Nodosariida. • The Buliminida. • The Robertinida. • The Rotaliida (smaller). • The Rotaliida (larger). • The Globigerinida.