biostratigraphy and paleoecology of cretaceous/tertiary boundary in ...
biostratigraphy and paleoecology of cretaceous/tertiary boundary in ...
biostratigraphy and paleoecology of cretaceous/tertiary boundary in ...
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Chapter Three Biostratigraphy<br />
Pessango, G. ultramicra (Subbot<strong>in</strong>a),, Archaeoglobiger<strong>in</strong>a cretacea (d<br />
Orbigny), A. blowi Passango, Gubler<strong>in</strong>a cuvillieri Kiko<strong>in</strong>e, Gumbelitria cretacea<br />
Cushman, G. dammula (Volosh<strong>in</strong>a) Hedbergella monmothensis (Olsson). In<br />
addition to these planktonic foram<strong>in</strong>iferal assemblages moderate benthonic<br />
foram<strong>in</strong>iferal Species were recorded (Fig 3.8). The age estimation <strong>of</strong> this<br />
biozone by (Li <strong>and</strong> Keller 1998a), records the time span <strong>of</strong> 70.39Ma to 69.56 Ma<br />
830 Ky estimat<strong>in</strong>g absolute ages based on magnetochron ages with 41ky/m,<br />
moderate rate <strong>of</strong> deposition (Fig.4.11)<br />
Age: early Maastrichtian.<br />
3.2.1.3- Contusotruncana contusa Interval Zone (CF6)<br />
Dalbeiez (1955) proposed the Globotruncana contusa Zone for the Upper<br />
Maastrichtian <strong>of</strong> Tunisia. Biostratigraphic <strong>in</strong>terval <strong>of</strong> this zone is def<strong>in</strong>ed by the<br />
FAD <strong>of</strong> Contusotruncana contusa (Cushman) at the base <strong>and</strong> last appearance<br />
(LAD) <strong>of</strong> Globotruncana l<strong>in</strong>neniana (d Orbigny) at the top. (plate. 1, Figs. 6-8). In<br />
the present study at Gali section, this Zone (CF6) covers an <strong>in</strong>terval <strong>of</strong> 25<br />
meters. This Zone yielded an assemblage <strong>of</strong> planktonic foram<strong>in</strong>ifera which<br />
totally resembles that <strong>of</strong> the underly<strong>in</strong>g Gansser<strong>in</strong>a gansseri Zone (CF7), except<br />
for the first appearance <strong>of</strong> Contusotruncana contusa (Cushman),<br />
Contusotruncana plicata White, C. patelliformis (G<strong>and</strong>olfi), , Globotruncana<br />
rosetta Carsey, Racemiguemel<strong>in</strong>a powli Smith <strong>and</strong> Pessango, Hedbergella<br />
holmdelensis Olsson, Rugoglobiger<strong>in</strong>a scoti (Bronnimann), <strong>and</strong> mark the<br />
term<strong>in</strong>ation <strong>of</strong> Guembelitria dammula (Volosh<strong>in</strong>a), Globotruncana gagneb<strong>in</strong>i<br />
Tilev, Globotruncana bulloides Vohgler, Glt. <strong>in</strong>signis (G<strong>and</strong>olfi), Glt. mariei<br />
Banner & Blow, Glt. ventricosa White, Globotruncanella havanensis<br />
(Voorwuk),Globiger<strong>in</strong>illoides boli Passango, Archaeoglobiger<strong>in</strong>a blowi<br />
Pessango, A. cretacea (d Orbigny).<br />
As def<strong>in</strong>ed above, the present Biozone (CF6) is correlatable with the Zone<br />
recorded by (Li <strong>and</strong> Keller, 1998a <strong>and</strong> b),<strong>and</strong> (Abramovich et al., 2002), at<br />
DSDP Site 525A. (Samir 2002), from Egypt. (Sharbazheri 2007), NE Iraq. To<br />
the lower part <strong>of</strong> Rosita contusa Zone recorded <strong>in</strong> the Northeast <strong>of</strong> Iraq by<br />
(Abawi et al., 1982 <strong>and</strong> Abdel-Kareem 1986), <strong>in</strong> Italy (Premoli Silva <strong>and</strong> Sliter<br />
1995, 1999) (Premoli Silva et al 1998), (Abdel-Kareem & Samir 1995) Egypt,<br />
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