Özet:

Regarding the consequential role of large benthic foraminifera associations in detecting undersea conditions, we have attempt to study these faunas in the 27 samples derived from Paleocene-Eocene sediments with a thickness of nearly 110 meters belonging to the Naghusan section located in the west Tafresh. The studied interval lithologically made up of sandy-marly limestone and tuff with a low percentage of sedimentary rocks such as sandstone. In this study, 17 species belonging to 9 genera of benthic foraminifera were identified and based on environmental index fossils, as various species of Assilina, Discocyclina and Nummulites genera, a carbonate semi-deep open marine environment has been suggested for these sediments. Indeed, an oligotrophic condition with relatively high lightening and normal salinity in a limy-sandy floor has been reported for the studied succession. Keywords: Paleoecology; lower eocene; west tafresh References: Adams, C. G., Lee, D. E., & Rosen, B. R. (1990). Conflicting isotopic and biotic evidence for tropical sea-surface temperatures during the Tertiary. Palaeogeography, Palaeoclimatology, Palaeoecology, 77(3-4), 289-313. Beavington-Penney, S. J., & Racey, A. (2004). Ecology of extant nummulitids and other larger benthic foraminifera: applications in palaeoenvironmental analysis. Earth-Science Reviews, 67(3-4), 219-265. Drinia, H., & Anastasakis, G. (2012). Benthic foraminifer palaeoecology of the Late Quaternary continental outer shelf of a landlocked marine basin in central Aegean Sea, Greece. Quaternary international, 261, 43-52. Gooday, A. J. (1994). The biology of deep-sea foraminifera: a review of some advances and their applications in paleoceanography. Palaios, 14-31. Hajian, J. (1997). Geology of Iran, Paleocene and Eocene in Iran [in Persian]. Hallock, P. (1987). Fluctuations in the trophic resource continuum: a factor in global diversity cycles?. Paleoceanography and Paleoclimatology, 2(5), 457-471. Hallock, P. (2005). Global change and modern coral reefs: new opportunities to understand shallow-water carbonate depositional processes. Sedimentary Geology, 175(1-4), 19-33. Hayward, B. W. (1999). Recent New Zealand shallow-water benthic foraminifera: taxonomy, ecologic distribution, biogeography, and use in paleoenvironmental assessment. Inst. Geol. Nucl. Sci. Monogr, 21, 264. Jorissen, F. J., de Stigter, H. C., & Widmark, J. G. (1995). A conceptual model explaining benthic foraminiferal microhabitats. Marine micropaleontology, 26(1-4), 3-15. Murray, J. W., Ecology, W. (1991). Paleoecology of Benthlc Foraminifera. Pomar, L. (2001). Types of carbonate platforms: a genetic approach. Basin Research, 13(3), 313-334. Pomar, L. (2001). Ecological control of sedimentary accommodation: evolution from a carbonate ramp to rimmed shelf, Upper Miocene, Balearic Islands. Palaeogeography, Palaeoclimatology, Palaeoecology, 175(1-4), 249-272. Racey, A., Bailey, H. W., Beckett, D., Gallagher, L. T., Hampton, M. J., & McQuilken, J. (2001). The petroleum geology of the early Eocene El Garia Formation, Hasdrubal field, offshore Tunisia. Journal of Petroleum Geology, 24(1), 29-53. Scheibner, C., Speijer, R. P., & Marzouk, A. M. (2005). Turnover of larger foraminifera during the Paleocene-Eocene Thermal Maximum and paleoclimatic control on the evolution of platform ecosystems. Geology, 33(6), 493-496. Scott, D. B., Medioli, F. S., & Schafer, C. T. (2007). Monitoring in coastal environments using foraminifera and thecamoebian indicators. Cambridge University Press. Gupta, B. K. S. (1999). Foraminifera in marginal marine environments. In Modern foraminifera (pp. 141-159). Springer, Dordrecht. Swati, M. A. F., Haneef, M., Ahmad, S., Naveed, Y., Zeb, W., Akhtar, N., & Owais, M. (2013). Biostratigraphy and depositional environments of the Early Eocene Margalla Hill Limestone, Kohala-Bala area, Haripur, Hazara Fold-Thrust Belt, Pakistan. Journal of Himalayan Earth Sciences, 46(2), 65. ‏ ‏ Tripati, A., & Elderfield, H. (2005). Deep-sea temperature and circulation changes at the Paleocene-Eocene thermal maximum. Science, 308(5730), 1894-1898. Zachos, J., Pagani, M., Sloan, L., Thomas, E., & Billups, K. (2001). Trends, rhythms, and aberrations in global climate 65 Ma to present. science, 292(5517), 686-693. Zachos, J. C., Dickens, G. R., & Zeebe, R. E. (2008). An early Cenozoic perspective on greenhouse warming and carbon-cycle dynamics. Nature, 451(7176), 279. Zhang, Q., Willems, H., & Ding, L. (2013). Evolution of the Paleocene-Early Eocene larger benthic foraminifera in the Tethyan Himalaya of Tibet, China. International Journal of Earth Sciences, 102(5), 1427-1445.  

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