2.1. Petrological analyses
This analysis involves petrography and heavy mineral separation.
The thin sections for petrography were prepared from representative
samples of the formations. The samples were first
impregnated and allowed to solidify for 24 h. They were then
ground with carborundum 90, 400 grit. The thicknesses of the
samples were further reduced on the Logitech cutting machine,
using carborundum 800 grit, from translucent to transparent
stages. The prepared sections were air dried and heated on the hot
plate after which Canada balsam was applied and heated to about
50 _C. They were covered with cover slips after cooling and then
soaked in acetone to remove excess Canada balsam around the
glass slides, washed in soap solution and distilled water, brushed,
and air dried. The thin sections were observed under a calibrated
scale microscope.
Fig. 4. Lithostratigraphic section of Well-LL2 (Mid-Lagoon).
O.A. Boboye, O.R. Nwosu / Quaternary International 338 (2014) 14e27 17
For heavy mineral separation, dilute HCl was added to 5 g
samples (52 mm) to disaggregate the samples. Samples were boiled
for about 30 min, washed with d water to reduce the effect of the
acid, and dried. The dried samples were then poured into the
separating funnel containing bromoform. Acetonewas added to the
separated heavy minerals to neutralize the bromoform and to aid
dryness. The separated heavy minerals were placed on the slides
using Canada balsam, allowed to dry, and viewed under the
binocular microscope. The results are presented in Tables 2 and 3
and Figs. 9e11.