Marine Science

p-ISSN: 2163-2421    e-ISSN: 2163-243X

2014;  4(2): 49-57

doi:10.5923/j.ms.20140402.04

Paleoecology of Upper Cretaceous Sediments in Central Iran, Kerman (Bondar-e Bido Section) Based on Ostracods

Bita Ghasem Shirazi1, Lida Bakhshandeh2, Abdollah Yazdi1

1Department of Geology, Islamic Azad University, Kahnooj Branch, Kerman, Iran

2Department of Geology, Science and Research Branch, Islamic Azad University, Tehran, Iran

Correspondence to: Bita Ghasem Shirazi, Department of Geology, Islamic Azad University, Kahnooj Branch, Kerman, Iran.

Email:

Copyright © 2014 Scientific & Academic Publishing. All Rights Reserved.

Abstract

In order to assess the biological potential of ostracods in response to environmental processes, in this study, the Upper Cretaceous sediments of Bondare Bido Section, has been studied. The study Section is located at 45 km away in South-West direction of the Kerman (Iran). The area between northern latitude 57˚17' 48 and western longitude 29˚49'44. Due to high sensitivity to environmental changes, the Ostracods are reliable indicators to determine water depth in Upper Cretaceous. On the bases of identified microfossils, the Upper Cretaceous sediments of the study area are Turonian-Maastrichtian in age. These deposits have been biostratigraphically and paleoecologicall point of view evaluated and boundary between stages are determined. Here we report 13 genuses of well preserved ostracods belong to two family Podocopida and Platycopida. The assemblage of ostracods and foraminifera are good indicator of ecological environment during deposition of Cretaceous sediments. The abundance of genus and species of planktonic foraminifera and the presence of some benthic foraminifera and ostracods, may indicate relatively deep and open marine (hemiplegic) environment for these deposits.

Keywords: Paleoecology, Central Iran, Ostracod, Upper Cretaceous, Bondare Bido Section

Cite this paper: Bita Ghasem Shirazi, Lida Bakhshandeh, Abdollah Yazdi, Paleoecology of Upper Cretaceous Sediments in Central Iran, Kerman (Bondar-e Bido Section) Based on Ostracods, Marine Science, Vol. 4 No. 2, 2014, pp. 49-57. doi: 10.5923/j.ms.20140402.04.

Article Outline

1. Introduction
2. Methodology
    2.1. The Geographical Location and Accessibility of Bondare Bido Section
    2.2. Lithostratigraphy of the Upper Cretaceous Sediments in Bondare Bido Section
    2.3. Evaluating of Ostracods in the Studied Section
    2.4. Paleoecological Studies
3. Temperature
4. Conclusions
Appendix

1. Introduction

It is for the first time that foraminifera & ostracods from the Bondare Bido Section were studied by the authors.
The Cretaceous sediments have covered vast area of Kerman. These deposits outcropping at north, north- west and south of Kerman city as an important mountains of Reef limestone.
Samples have been systematically taken from Bondare Bido section and subjected for investigation.
Most of the ostracods have been identified at genus level and for determination of their age we used present foraminifera, associated with ostracods. The identified index fossils of foraminifera include:
Whiteinella archaeocretacea Pessagno, Marginotruncana sigali (Reichel), Dicarinella concavata (Brotzen), Dicarinella asymetrica (Sigal), Muricohedbergella holmdelensis Olsson, Contusotruncana fornicata (Plummer), Macroglobigerinelloides bollii (Pessagno), Globotruncana ventricosa, Globotruncanita elevata (Brotzen), Radotruncana calcarata (Cushman), Globotruncanella havanensis (Voorwijk), Globotruncana aegyptica Nakkady, Gansserina gansseri (Bolli), Contusotruncana contuse.
The assemblage of index foraminifera fossils suggest Turonian-Maastrichtian age for Bondare Bido Sections.

2. Methodology

The ostracods were studied in three stages including library, field and laboratory studies. In field study, a section was chosen and sampling systematically was done.
In the present study, 58 samples of Upper Cretaceous sediments with a thickness of 265m has have been studied. About 300g of each sample was soaked in water for a few days, and then samples 12cc of 15% hydrogen peroxide solution then samples were macerated using, sieves with a diameter of 30 and 60 meshes.
The dried samples were poured into a tray and ostracods were picked up under optical microscope. After studying and Scanning Electron Microscopy was applied for identification.

2.1. The Geographical Location and Accessibility of Bondare Bido Section

The Bondare Bido Section is located at 45 km away in South-West direction of the Kerman. The area between northern latitude 57˚17' 48" and " western longitude29˚49'44, this section is located in 1:100,000, geological map of Rayen.
The study area is accessible through the asphalt road of Kerman-Bam (Figure 1).
Figure 1. Accessing roads to Bondare Bido Section, IRAN Roads ATLAS, Gitashenasi Cartographic Geographical Institute (2007)

2.2. Lithostratigraphy of the Upper Cretaceous Sediments in Bondare Bido Section

In thick cream-colored layer of limestone in this region with Cenomanian age is overlaid with other sedimentary series as below:
- The alternation of medium - thick and cream- to yellow-colored layer of limestone with marl with thickness of 80m.
- The alternation of marl with green or cream-colored limestone with thickness of 15m.
- The thick layer of cream-colored limestone with thickness of 20m.
- The green-colored marl with thickness of 50m.
- The medium to thick and yellow- to cream-colored layers of limestone with thickness of 50m
- The red sandstone with thickness of 15m.
- The gray- to green-colored shales with thickness of 30m.
- The red sandstone with thickness of 5m.
These sediments are overlaid by Kerman conglomerate.

2.3. Evaluating of Ostracods in the Studied Section

In this section, 13 genuses of ostracods were identified.
The most famous families are Platycopida with most abundant genus of Cytherella and Cytherelloidea, Podocopida, Pontocyprella, Bairdoppilata, Pterygocythereis, Peleriops.
Ostracods in Bondare Bido Section include:
The ostracods in samples from lower part of this section are less in numbers. The samples of with the Upper parts of section, Campanian-Maastrichtian in age yielded good number of ostracod. The number and diversity of ostracods are low in shales and calcareous shales. The numbers of ostracods are significantly increased in marls, median shales and calcareous bands. The diversity of ostracods has been reduced by increasing depth and transgression sea water, in this region.
The type of ostracod fauna indicates the depositional environment in different parts of the studied section in a way that Cytherelloidea and Haplocytheridea genuses are related to inner to middle neritic parts. Also, in most samples, the presence of Cytherelloidea genus indicates a moderate to hot climate depositional condition.
Genus such as Paracypris indicates an increase in the depth and the presence of genus such as Brachycythere sp represents a reduction in the depth of the environment. The Cytherella specifies open sea with medium depth and neritic conditions of outer shelf to outer bathyal. The Paracypris and Cytherella show marine conditions with normal salinity.
Figure 2. The stratigraphic column of Upper Cretaceous sediments in Bondare Bido Section

2.4. Paleoecological Studies

The Bondare Bido Section comprises diverse assemblages of ostracods fossil. The Platycopida family is one of the most famous families with its most abundant genuses of Cytherelloidea and Cytherella which has been found. In addition, genus of Pterygocythereis, Pontocyprella and Bairdoppilata are the abundant fossils of the platycopida family. Meanwhile, genus Cytherella with 29% and genus Cytherelloidea with 24% are the most abundant genus. The paleoecological studies are by samples were counted and percentages were done and their graphs were drawn. Carried out by counting the numbers of species and graphs of their percentage is plotted (Fig.3 and 4).
Figure 3. The frequency percentage of Cytherella in Bondare Bido Section
Figure 4. The frequency percentage of Cytherelloidea in Bondare Bido Section
The interpretation of the above-mentioned graphs enable us to disuse the, ecological factors based on ostracods in the studied section as follow:
- Salinity
Ostracods basically live in all aquatic environments with different salinities (Moore 1961). The presence of the reported ostracod species and genuses such as Haplocytheridea in the Bondare Bido Section indicate marine environments with medium salinity of 36 to 39 per thousand and considering of ostracods of this section, it can be said that the salinity of water during the deposition of sediments was between 30 to 40 per thousand.
- Oxygen
The rate of dissolved oxygen in water plays an essential role in distribution of ostracods. Some ostracods species are good indicator of the rate of oxygen in environment. In many gatherings of ostracods in sediments. The percentage of the presence of the fossil ostracods of Platycopids family may use to determine the past oxygen level and as an oxygen dissolution scale in paleo seas. An increase in the presence of fossil Platycopids ostracods indicates the reduction of oxygen in the environment (Whatley et al, 2003).
Considering the presence of fossil Platycopids ostracods (40 to 60%) (Figure 5), one can say that the Upper Cretaceous sediments of Bondare Bido Section is deposited at an environment with moderate oxygen level. Table 1 shows the rate of dissolved oxygen in the water in terms of ml per liter and based on the percentage of the presence of Platycopids.
Figure 5. Frequency percentage of Podocopid and Platycopid in Bondare Bido Section
Table 1. Rate of dissolved oxygen in water in terms of ml/l and based on the percentage of Podocopids (according to Whatley and Bajpai 2000)
     
Changes of the percentage of oxygen of the environment have a direct relation with the frequency and diversity of ostracods, therefore the frequency and diversity of ostracods will be declined by decreasing the rate of oxygen in environment. Since the fossil ostracods in Bondare Bido Section had a moderate frequency and diversity, this may confirm the on oxygenated environment.
Some ostracods such as Xestoleberididae from Xestoleberise family, can not survive in low-oxygen environments. The absence of this genus moderate in the studied section, may indicate the oxygen condition was not dominant in the environment during the deposition of this section.
- Depth
Many important ecological factors such as density, hydrostatic pressure, light, oxygen, temperature and size of bottom are controlled by depth. Ostracods live at various depths of sea from coastline to abyssal area (Cabral, et al 1897). Depth is one of the most important factors that control the diversity of species of ostracods (Cass, 2002). Environment is the main factor in natural selection and evolution of many different forms and structures in the outer skeleton of ostracods. Shape and ornamentations of Carapace reflect their living environment (Gwyneth et al, 1991).
In shallow sea-beds, ostracods have thick valves with eye spots, hard carapace, and amphidetic hinge line and pore channels in beds with coarse sediment. In shoreline (neritic), deeper waters with more fine-grained sediments contain ostracods with smooth, thin, mostly transparent carapaces with a relatively weak hinge line, blind with eye spots.
The presence of Cytherelloidea, Bairdoppilata and Pontocyprella genuses are good indicator of deep sea environment and along with the presence of genus Brachycythere, this fossil assemblage represents abyssal platform depositional condition.
The ratio of carapaces to valves is used to determine the energy of depositional environment. If the number of carapaces is more than valves, this will indicate the quiet and low energy environment condition and vice versa. Since in the studied area, the number of carapaces and valves is almost equal, therefore the environment energy could be moderate.

3. Temperature

Most of the ostracods have the capability of enduring certain range of temperature. Like most of the other creatures, the ostracod assemblages are more diverse in shallow waters of low geographical latitudes than fossil ostracods belong to high latitudes (Friedwald and Mostafavi, 1998). Since the identified medium depth environment, therefore they have been benefited by proper light and temperature. The frequency of Cytherelloidea species indicate warm climatic conditions during Upper Cretaceous for Bondare Bido Section

4. Conclusions

In assessing and studying the fossil assemblages of Bondare Bido Section, 13 genus of ostracods were identified. Based on the identified planktonic foraminifera and ostracods, in Bondare Bido Section, the time interval of Upper Cretaceous sediments is proposed as from Turonian to Maastrichtian.
The ostracod genus such as Haplocytheridea of Cretaceous sediments in Bondare Bido Section, may indicate marine environments with medium salinity of 36 to 39 per thousand. On the bases of identified ostracod assemblages of studied section, it can be said that during deposition of this formation, the salinity of sedimentary basin was 30 to 40 per thousand.
The increase of fossil ostracod of platycopid families show the reduction of the oxygen of the environment by (Whatley et al, 2003). With regard to the presence of platycopids in the studied section which is 40 to 60%, and it can be concluded that during the deposition of Upper Cretaceous sediments in Bondare Bido Section, the environment had medium oxygen.
The presence of Cytherelloidea, Bairdoppilata and Pontocyprella, indicate deep sea environment and along with Brachycythere, this ostracod fossil assemblages indicate the deep part of the platform.
Since the identified medium depth environment, therefore they have been benefited by proper light and temperature. The frequency of Cytherelloidea species indicate warm climatic conditions during Upper Cretaceous for Bondare Bido Section.

Appendix

Plate 1.
Plate 2.
Plate 3.
Plate 4.
Plate 5.
Plate 6.
Plate 1
1-9: Cytherella spp., Bondar bido section, Campanian-Maastrichtian
1: Carapace, Left valve
2: Carapace, Left valve
3: Carapace, Left valve
4: Carapace, Left valve
5: Carapace, Right valve
6: Carapace, Left valve
7: Left valve
8: Left valve
9: Left valve
Plate 2
1-4: Cytherella spp.,Bondar bido section, Campanian-Maastrichtian
1: Left valve
2: Left valve
3: Carapace, Left valve
4: Right valve
5-7: Bairdoppilata spp.,Bondar bido section, Campanian-Maastrichtian
5: Left valve
6: Carapace, Right valve
7: Carapace, Right valve
8-9: paracypris spp., Bondar bido section, Campanian-Maastrichtian
8: Carapace, Right valve
9: Carapace, Right valve
Plate 3
1: Pontocyprella sp., Bondar bido section, Campanian-Maastrichtian
Carapace, Left valve
2: Eucythere sp. , Bondar bido section, Campanian-Maastrichtian
Right valve
3: Pterygocythereis sp. , Bondar bido section, Campanian-Maastrichtian
Left valve
4-5: Brachycythere sp. , Bondar bido section, Campanian-Maastrichtian
4: Carapace, Left valve
5: Carapace, Right valve
6: Indet. gen.et sp. , Bondar bido section, Campanian-Maastrichtian
Left valve
7-8: Pterygocythere spp. , Bondar bido section, Campanian-Maastrichtian
7: Carapace, Left valve
8: Carapace, Left valve
9: Haplocytheridea sp. , Bondar bido section, Campanian-Maastrichtian
Left valve
Plate 4
1-2: Cristaeleberis spp. ,Bondar bido section, Campanian-Maastrichtian
1: Carapace, Left valve
2: Right valve
3: Veeniacythereis sp. , Bondar bido section, Campanian-Maastrichtian Left valve
4: Cytherelloidea sp. , Bondar bido section, Campanian-Maastrichtian Right valve
5-9: Peleriops spp. , Bondar bido section, Campanian-Maastrichtian
5: Left valve
6: Left valve
7: Carapace, Left valve
8: Right valve
9: Carapace
Plate 5
1: Globotruncanita elevata (Brotzen), Early Campanian
2: Globotruncana ventricosa White, Middle Campanian
3: Globotruncana ventricosa White, Middle Campanian
4: Globotruncana bulloides Vogler, dorsal view, Campanian
5: Contusotruncana fornicata (Plummer), Santonian
6: Gansserina gansseri (Bolli), Maastrichtian
7: Globotruncana arca (Cushman), Late Campanian
8: Globotruncana bulloides Vogler, Santonian
Plate 6
1: Contusotruncana fornicata (Plummer), Campanian
2: Macroglobigerinella bollii (Pessagno), Santonian
3: Macroglobigerinella prairiehillensis (Pessagno), Campanian
4: Globotruncana bulloides Vogler, Campanian
5: Globotruncana linneiana (d' Orbigny), Middle Campanian
6: Globotruncana ventricosa White, Campanian
7: Globotruncanita stuarti (de Lapparent), Late Campanian
8: Globotruncanita conica (White), Late Maastrichtian

References

[1]  Bolli H. M., Beckman J. P., Saunders J. B., 1994- Benthic Foraminiferal Biostratigraphy of the South Caribbean Region, Cambridge University.
[2]  Bolli, M.H., Saunders, J.B. & Perch- Nielsen, K. 1985: Plankton Stratigraphy; Cambridge University Press, Cambridge, vol.I, pp.87-154.
[3]  Benson, R. H. & J. O. Tatra (1964) - Faunal description of Ostracoda of the marlbrook marl (Campanian), Arkansas University, Kansas Paleontology Contribution, Arthropoda, Art. 7: 1-32, pls 1-6.
[4]  Bolli, H.M. 1966-: Zonation of Cretaceous to Pliocene marine sediments based on Planktonic foraminifera. Boletin Informativo Asociacion Venezolana de Geologia , Mineriay Petroleo, 2-35.
[5]  Caron, M. 1985-Cretaceous Planktonic Foraminifera, in Boli et al.: Plankton Stratigraphy, Cambridge University Press, P.17-86.
[6]  Cabral, M.C., Colin, J.P., & Azeredo, A.C., 1897. Taxonomy and Palaeoecology of new brackish osteracoda species from the Middle Cenomanian of lousa Lisbonregion, Portugal. Palaeogeography, Palaeoclimatology, Palaeoecology, 264: 250-262.
[7]  Hazel, J.E., and Brouwers, E.M., (1982). Biostratigraphic and chronostratigraphic distribution of ostracodes in the Coniacian-Maastrichtian (Austinian- Navarroan) in the Atlantic and Gulf Coastal Province. In Maddocks, R.F. (Ed.), Texas Ostracoda, Guidebook of Excursions and Related Papers for the Eighth International Symposium on Ostracoda: Houston, TX (Univ. of Houston), pp. 166-198.
[8]  Iran roads atlas (2007), Gitashenasi Cartographic Geographical Institute, Iran.
[9]  Khosrow Tehrani, K. - M. (1972), Microfossils of Cretaceous deposits in Irankuh.
[10]  Li, L., and Keller, G., (1999). Variability in Late Cretaceous climate and deep waters: evidence from stable isotopes; Marine Geology 161: 171-190.
[11]  Li, L., Keller, G. and Stinnesbeck, W. (1999). The Late Campanian and Maastrichtian in northwestern Tunisia: Paleoenvironmental inferences from lithology, macrofauna and benthicforaminifera. Cretaceous Research 20, 231-252.
[12]  Loeblich, A.R., Jr- Tappan, H. 1988-Foraminiferal General and their Classification: Van Nostrand Reinhold Company, New yourk, 2 Volumes, 970p. plus 212p, and 847 pl.
[13]  Loger, P., 2003. Paleobiogeography of late Early Cretaceous to Early Paleocene marine ostracoda in Arabia and North to Equatorial Africa. Palaeogeography, Paleoecology, Palaeoclimatology, 196: 319-349.
[14]  Moore, R.C., 1961. Treatise on invertebrate paleontology, Part Q, Arthropoda 3, Osteracoda. Geol. Soc. America and Univ. Kansas, 422 p.
[15]  Premoli Silva, I., and Verga, D., (2004). Practical Manual of Cretaceous Planktonic Foraminifera, course 3, in Verga, D., and Rettori, R. (Editors), International School on Planktonic Foraminifera: Universities of Perugia and Milano, Tipografiadi di Pontefelcino, Perugia, Italy, 283 p.
[16]  Robaszynski F.,Caron M., Gonzalez Donoso J.M., Wanders A.A.H. Atlas of Late Cretaceous Globotruncana 1988.
[17]  Rosenfeld, A. & M. Raab (1974) - Cenomanian-Turonian ostracods from the Judea Group in Israel. Bulletin of the Geological Survey of Israel, Jerusalem, 62: pp. 1-64.
[18]  Seyed Imami et al (1971), Paleontology and stratigraphy of Cretaceous deposits in South and South-East Kerman.
[19]  Sliter, W.V., and Baker, R.A., (1972). Cretaceous bathymetric distribution of benthic foraminifera; Journal of Foraminiferal Research 2: 167-183.
[20]  Swain, F.M., 2007. Biostratigraphy of Cretaceous ostracoda from wells in South Carolina. 5: 1- 30.
[21]  Whatley, R., & Bajpai, S., 2000. Further nonmarine ostracoda from the Late Cretaceous intertrappean deposits of the Anjar region, Kachchh, Gujarat, India. Micropaleontologie, 43: 173- 178.
[22]  Whatley, R.C., Pyne, R.S., & Wilkinson, I.P., 2003. Ostracodes and palaeo-oxygen levels, with particular reference to the Upper Cretaceous of East Anglia. Palaeogeography, Paleoecology, Palaeoclimatology, 194: 355-386.
[23]  Zahedi (1973), Doctoral Dissertation, Geology of Kerman, district 3.