FORAMINIFERAL BIOSTRATIGRAPHY AND PALEOENVIRONMENT OF THE PATALA AND NAMMAL FORMATIONS AT THE PALEOCENE/ EOCENE BOUNDARY IN SALT RANGE AND SURGHAR RANGE, PAKISTAN

This thesis deals with the distribution patterns, zonations and correlation among 165 species of the Late Paleocene to Early Eocene planktonic, smaller and larger benthic foraminifera hosted by the Patala and Nammal formations. The study is based on the high resolution analysis of 215 samples from the five well-known outcrop sections of the Salt Range and Surghar Range, Upper Indus Basin, Pakistan.\ud \ud Four related aspects in this study were focused upon: (1) a better systematic documentation of the smaller benthic species especially newly erected by Haque (1956), (2) to generate a high resolution data regarding the planktonic and smaller benthic foraminifera and to establish their respective zonation schemes, (3) to test the- European shallow benthic zonation schemes and to tie them with open marine planktonic zones and (4) to establish the PIE boundary through the excursion of planktonic, smaller and larger benthic foraminiferal turnovers.\ud \ud The SEM photographs coupled with taxonomical revision provided a better documentation of smaller benthic foraminifera. Some of the species and genera of Haque (1956) have fallen into synonyms. During this study, two new species were described. The first named Pseudowoodella patalaensis which was recovered from the basal part of Patala Formation. Its widespread distribution and fairly restricted range (within P4c Zone) make this species potentially useful biostratigraphic marker. The second named Textularia aftabi, also from the Patala Formation but its distribution and range could not be confirmed.\ud \ud The high resolution data of the planktonic foraminifera revealed several discrepancies in their relative stratigraphic ranges. The most significant were the diachronous longer range of PI. pseudomenardii and diachronous shorter range of M. velascoensis. Almost simultaneous LOs of these two taxa hindered to establish standard M. velascoensis Zone. Whereas on the other hand the overlapping range of PI. pseudomenardii with several younger species such as Acarinina wilcoxensis berggreni, A. broedermanni, A. wilcoxensis strabocella, Pseudohastigerina wilcoxensis, Muricoglobigerina soldadoensis, Morozovella formosa gracilis, M. subbotinae, M. marginodentata and M. lensiformis was a strong evidence about its longer range. This assemblage specified a horizon coeval to the M. velascoensis Zone of Arenillas & Molina (1996). This anomaly has been further qualified by the overlapping of a major part of AI. cucumiformis Zone or N. deserti Zone (=S85) of the shallow water taxa and by the upper part of NP9 Zone. In this respect, the zonation of Blow (1979) was found most suitable, therefore, adopted with slight modification for the Salt Range. Six planktonic foraminiferal zones were established and correlated with other standard zonation schemes. Another anomaly in this area might be an early entry of M. aragonensis which has been observed within the middle of NP11 Zone and just above the upper boundary of N. globulus (=5B8) Zone. Due to this reason M. formosa event which accompanies M. caucasica, is represented by a period of very short duration throughout the study area.\ud \ud Due to the lack of continuos shallow marine carbonate environments, all the zones of shallow water zonation schemes could not be established. Consequently, a benthic zonation scheme based on the combination of smaller and larger benthic foraminifera has been proposed applicable to the Salt Range.\ud \ud Recognition of NP9/NP1 0 boundary in Salt Range is very problematic which was overlooked due to rare to absent T. bramlettei, T. contortus and persistence of Zone NP9 species into zone NP10 (established through literature). Moreover, recognition of NP9/NP10 boundary at a horizon which is just prior to the FO of M. formosa formosa is also puzzling.\ud \ud Integration of several Late Paleocene to Early Eocene shallow water and deep marine foraminiferal zonations and calcareous nannofossil zones (according to literature) emerged in the form of a biostratigraphic framework applicable to the Salt Range. This framework near the PIE boundary shows close similarities with the zonal oorrelation of Schaub (1981) in contrast to that of Serra-Kiel et al. (1996). This framework reflected the presence of two hiatuses around the P-E transition.\ud \ud The high resolution data shows that the paleoceanographic changes occurring around the PIE boundary, effected the both shallow and deep marine foraminiferal paleocummunites. The three distinct turnovers of the of planktonic, smaller and larger benthic foraminifera occur very close to each other within a thin sedimentary layer (about 2m thick), at the thin limestone bed which separates the middle and upper units of Patala Formation. This horizon lies within the upper most part of Mg. soldadoensis Zone (this study) and apparently in the upper most part of P4c Zone of Berggren et a!. (1995). Magnetostratigraphic data to estimate the total time span for these turnovers was not available. Following Blow (1979) and apparently Cavelier & Pomerol (1986), the PIE boundary has been proposed at the LO of PI. pseudomenardii within AI. cucumiformis (585) Zone. This horizon according to the accompanying planktonic foraminiferal assemblage is coeval with the base of M. velascoensis Zone of Arenillas & Molina (1996). The other potentially useful planktonic foraminiferal candidate to define this boundary is. FO of A. wilcoxensis berggreni.\ud \ud The base IIerdian in Europe lies at the horizon defined by the base of Alveolina cucumiformis, Nummulites deserti/frassi or Assilina prisca Zone which is an event related to the middle of NP9 zone and lower part of P5 Zone. In the Salt Range, N. deserti, A. dandotica, A. prisca appeared at NP8/NP9 zonal boundary whereas Alveolina vredenburgi (=AI. cucumiformis) appeared in the middle of NP9. 80th event occur within Mg. soldadoensis Zone (this study). Therefore, it is recommended that for the Salt Range, the base IIerdian must be exclusively defined at the base of AI. cucumiformis Zone.\ud \ud Paleoenvironmental data indicates that basin became tectonically active during the later part of late Paleocene which produced a major depression in the . middle of the study area (Khairabad section). The wide. spread transgressipon in the Early Eocene time has been encountered possibly coupled with tectonic subsidence