biostratigraphy and paleoecology of cretaceous/tertiary boundary in ...

Chapter Five
Conclusion
16- The terminal decrease in species richness began from the base to
the end of Zone CF1 (Gali section) and continued upwards till the upper most
part of Cretaceous biozone Zone CF1, the same thing in Qulka and Sirwan
sections. The decline is also coupled with the trend of decrease in p/b
ratios. On the other hand, a slight increase is recorded in the percentages
of arenaceous morphotypes. These criteria indicate shallowing regressive
phase in the end of Maastrichtian basin where the estimated water depth
ranges from middle to outer shelf, around 50 to 150m. depth.
17- The planktonic assemblages of the lower Danian in (P0) in
Smaquli area, and (P0&Pá) from Dokan and Sirwan valley are
characterized by no recording of planktic foraminiferal assemblage
except for (Hedbergella monmothensis & Guembelitria cretacea), in the
last 25cm of (P0) at Smaquli section. Little increase in Agglutinated
percent at Smaquli and Sirwan valley refers to the shallowing episode
around 10-50m. Afterward planktic foraminiferal assemblage, p/b ratios,
Agglutinated percentages and species richness from Smaquli, Sirwan
valley and Dokan in (Pá, P1a &p1b) (Early Paleocene), indicate shallow
water bathymetry of inner to middle neritic around 50 - 70m. depth.
18- A graphical method of correlation constructed by using the data
collected from all stratigraphical section. As indicated, low sedimentation rate in
initial part on (R. fructicosa Zone) at Smaquli area compared with highest
sedimentation rate at both Qulka and Sirwan sections. Later one from
P.hariaensis Zone to S. triloculinoides Zone (Upper Late Maastrichtian-Lower
Danian), the graphical line shows best-fit line of 45 0 which indicate similar rate
of depositions.
19- The mean sedimentation rate or average sediment rate by biozone
(m/myr) or years/meter was estimated in all studied stratigraphic successions
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