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

Chapter Three Biostratigraphy
contact line of K/T boundary in the field. As there is no sign for the presence of
an unconformity, we propose that this interval may be equivalent to both P0 &
Pá (G. cretacea - P. eugubina Zone). In addition to these categories the
sedimentation rate of deposition in all studied sections particularly in Sirwan
section, closely at Cretaceous/Tertiary boundary recorded high to very high rate
of sedimentation which reveals continuous uninterrupted sedimentary
sequences. Otherwise the significant amount of conglomerate beds within the
studied upper part of Tanjero Formation represented by 7 repeated beds of 0.5
to 2 meters thickness) and three conglomerate beds within the lower part of
Kolosh Formation. That reveals the intraformational conglomerate beds of
limited lateral extensions. (Figs. 2.3 & 2.4), this could be attributed to either its
extremely short duration, or its restriction to near shore, or diluted in
foraminiferal survivorship rather than open ocean environments as outlined by
Berggren & Norris, (1997). Entirely the presence of three local conglomerate
beds in the upper most part of Tanjero Formation in Qulka section sustain and
displays the same valid conception. (Fig.2.11)
3.2.2.4- P1. Parvularugoglobigerina eugubina - Praemurica uncinata
Interval Zone
(P1; defined in Berggren et al., 1995, emend. of Berggren & Miller, 1988).
Definition: Biostratigraphic interval between the LAD of Parvularugoglobigerina
eugubina at the base and the FAD of Praemurica uncinata at the top.
According to Berggren & Norris (1997) and Olsson et al.,( 2000) the P1 zone is
subdivided into three subzones based on the sequential appearances of
Subbotina triloculinoides (P1a/P1b boundary) and Globanomalina compressa
/Praemurica inconstans (P1b/P1c boundary). In the studied area of (Gali, Qulka
and Sirwan) sections only, P1a Zone and Lower part of P1b Zone encountered.
(Fig. 3.13)
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