Lecture 2

1. Lecture 2 Collection, Preparation and Examination

2. Collection, Preparation and Examination (Technical methods) • Foraminifera occur on a wide variety of substrates. • At all depths in the marine realm. • They are also transported by currents before burial in the sediment. • They are therefore found fossilized in most types of sedimentary rock, particularly in clays and marls. • Foraminifera are usually scarce in coarse sands but they are often abundant in silts and fine sands, especially if glauconitic. • Many limestones are built up of foraminifera but are often too hard, they can then only be studied in thin section.

3. (A)-Field (surface) Sampling • Normally, smaller foraminifera are only rarely seen in hand specimens of rock samples. • Larger foraminifera can be collected in the field like other macroscopic invertebrate fossils as in the case of fusulinids, alveolinids and nummulitids. • They may also be observed in the weatheredsurfaces as well as on bedding and jointplanes. • Larger foraminifera may also be picked up or sieved out of sediment on talusslopes. • Nummulitesgizehensis is so- abundant in the middleEocene of the Sahara especially from the Mokattamlimestone of the GreatPyramids in Egypt.

4. An investigation of the stratigraphic distribution of microfossils should commence with study of a set of samples representing the standard stratigraphic sequence of the area. • Samples for stratigraphic purposes are taken at regular intervals, the interval depending upon the rock, the thickness and character of strata involved and the available time. • Collecting of rock specimens should be supplemented by a special search for soft, easily washed rocks as sandyclays, marls, fineargillaceoussands and shales. • About 250 gm weight of sample is usually considered sufficient. • A graphic lithological log should be drawn to accompany the detailed description with the position of the samples shown exactly. • If possible Polaroid photographs should be taken of the section with samplebags in position.

5. (B)- Samples from borings (bore holes): • Samples from deep wells, from cores, are the most suitable material for the stratigraphic application of micropaleontology. • Samples representing each 10 ft (3m) interval are usually taken. • The drilling mud is washed off and the material split into sub samples. • Contamination with fossils and rock fragments from higher parts of the section must be anticipated in all loose material from wells. • In such material only the first appearance of species in the course of drilling provides useful stratigraphic horizons.

6. Sample Preparation The general procedure is as follows: • Crushing and boiling. • Decanting. • Drying. • Storage. • Separation of microfossils. • Mounting of microfossils. • Identification and recording.

7. 4 3 5 7 6 3 4 5 7 6

9. Transmitted binocular microscope Reflected binocular microscope

10. Diagram of scanning electron microscope

11. scanning electron microscope

12. This includes a gold coating MED

13. Paleontology Teaching Laboratory Reflected light binocular microscope Washing sieve