Hamzeh Ali Report( Study of thin sections from H1 to H80)

259 Pages·2017·26.31 MB·English

Microfacies, biostratigraphy and sedimentary environments of
the Eocene sedimentary successions in the Zagros and Sanandaj-
Sirjan Zone (Iran)

Mikrofazies, Biostratigraphie und Ablagerungsräume der eozänen Schichtenfolge des
Zagros-Gebirges und der Sanandaj-Sirjan-Zone (Iran)

der Naturwissenschaftlichen Fakultät der Friedrich-Alexander-Universität Erlangen-Nürnberg

zur

Erlangung des Doktorgrades Dr. rer. nat. vorgelegt von

Banafsheh Almansinia

Aus
Tehran in Iran

i
Als Dissertation genehmigt

von der Naturwissenschaftlichen Fakultät

der Friedrich-Alexander-Universität Erlangen-Nürnberg

Tag der mündlichen Prüfung: 2017/08/02

Vorsitzende/r des Promotionsorgans:Prof. Dr. Georg Kreimer

Gutachter: Prof. Dr. F.T. Fürsich
Prof. Dr. R. Höfling

ii
In the name of God

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Statement

I hereby certify that the following thesis entitled:
"Microfacies, biostratigraphy and sedimentary environments of the
Eocenesedimentary successions in the Zagros and Sanandaj-Sirjan Zone (Iran)"
has not yet been submitted for any degree, nor has it been submitted as part of the
requirements for a degree to any other university or institution other than the FAU Erlangen-
Nürnberg.
This thesis is a new and original research study and has been written by me, Banafsheh
Almasinia. Any help in the preparation and execution of this piece of research has been
properly acknowledged.
I also certify that all literature and data sources used in this study are specified in this thesis.
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Abstract
Two Eocene sections in the Zagros Mountains and two in Sanandaj-Sirjan Zone of west and
cental Iran have been investigated with the purpose to determine the age of the sections based
on planktonic and benthic foraminifera, to analyze the sedimentary micofacies, sedimentary
environments, sequence stratigraphic pattern, diagenetic processes, stable isotopes (δ18O,
δ13C), and to determine the absolute age span using strontium isotopes. Based on
foraminifera, the Shalamzar section (446.2m) belongs to the Middle Eocene (Lutetian), the
Hamzeh-Ali section (172m) belongs to Upper Cuisian-Lutetian, and the Zefreh section (43m)
to the Bartonian and Priabonian. Finally, the Soh section (171m) is Priabonian in age. The
former two sections are from the Zagros Mountains, the latter two from the Sanandaj-Sirjan
Zone. The carbonate microfacies consist mainly of mudstone, wackestone, packstone, and
occasionally grainstone with a variety of planktonic and benthic foraminifera. Altogether 17
microfacies could be recognized. According to Wynd (1965) six subzones could be
determined in the sections, one belonging to the Late Early Eocene (No.46), the other five to
the Middle and Late Eocene (49-53). In the Sanandaj-Sirjan Zone also siliciclastic facies
occur (mainly siltstone, sandstone, and conglomerate). For the Shalamzar section a
homoclinal ramp is postulated, whereas the Hamzeh-Ali section conforms to a distally
steepened ramp. In the Hamzeh-Ali section five depositional sequences corresponding to
third-order sea-level fluctuations could be recognized, in the Shalamzar section three, in the
Zefreh section two, and in the Soh section three depositional sequences. Post-depositional
and diagenetic processes include bioturbation, cementation, dolomitization, silicification and
formation of porosities. Based on oxygen stable isotopes paleotemperature values for the
Hamzeh-Ali section averaged 28°C and for the Shalamzar section 22°C. Three diagenetic
trends have been determined using organic matter: In the Hamzeh-Ali section, most samples
were affected by marine diagenesis and a few samples by shallow burial diagenesis; samples
of the Shalamzar section were affected by marine to burial diagenesis; in the Soh section
most samples indicate shallow burial diagenesis and a few samples meteoric diagenesis. In
the Zefreh section, all samples were affected by shallow burial diagenesis. Based on
strontium isotope analyses the Hamzeh-Ali section could be chronostratigraphically placed in
the Cuisian and Lutetian, whereas the Shalamzar section belongs to the Lutetian. The Zefreh
section belongs to Rupelian and the Soh section to the Priabonian—Rupelian.
Keywords: Zagros, Sanandaj-Sirjan Zone, Iran, Eocene, Jahrum Formation, biostratigraphy,
sequence stratigraphy, stable isotopes, strontium dating, diagenesis, microfacies

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Zusammenfassung
In eozänen Schichten des Zagrosgebirge (West-Iran) und der Sanandaj−Sirjan-Zone
(Zentraliran) wurden jeweils zwei Profile untersucht. Im Einzelnen wurden die Profile
biostratigraphisch mittels benthischer und planktonischer Foraminiferen eingestuft, ihre
Mikrofazies wurde analysiert und die Ablagerungsräume, sequenzstratigraphische Muster
und diagenetische Prozesse rekonstruiert. Außerdem wurden stabile Sauerstoff- und
Kohlenstoffisotopenuntersuchungen (δ18O, δ13C) durchgeführt sowie absolute
Altersbestimmungen mittels Strontiumisotope. Basierend auf Foraminiferendaten wird das
Shalamzar-Profil (446.2 m) in das mittlere Eozän (Lutetium) eingestuft, das Hamzeh-Ali-
Profil (172 m) in das obere Cuisium−Lutetium, das Zefreh-Profil (43 m) in das Bartonium
und Priabonium und das Soh-Profil (171 m) in das Priabonium. Die beiden erst genannten
Profile befinden sich im Zagrosgebirge, die anderen in der Sanandaj−Sirjan-Zone. Die
Karbonatmikrofazies besteht vorwiegend aus Mudstone, Wackestone und Packstone, sowie
gelegentlich Grainstone. Insgesamt wurden 17 Mikrofaziestypen unterschieden, die eine
reiche Fauna aus planktonischen und benthischen Foraminiferen enthalten. Basierend auf
einem unveröffentlichten Report von Wynd (1965) konnten sechs Subzonen ausgeschieden
werden, von denen eine (Nummer 46) dem oberen Untereozän angehört, die fünf anderen
(49-53) dem Mittel- und Obereozän. In der Sanandaj−Sirjan-Zone treten auch siliziklastische
Sedimente auf (vorwiegend Siltsteine, Sandsteine und Konglomerate). Für das Shalamzar-
Profil wird als Ablagerungsraum eine homoklinale Rampe angenommen, während das
Hamzeh-Ali-Profil als distal versteilte Rampe interpretiert wird. Im Hamzeh-Ali-Profil
wurden fünf Ablagerungssequenzen, die Meeresspiegelschwankungen 3. Ordnung
entsprechen, ausgeschieden, im Shalamzar-Profil drei, im Zefreh-Profil zwei und im Soh-
Profil drei Ablagerungssequenzen. Nach der Ablagerung wurden die Schichten bioturbiert.
Diagenetische Prozesse beinhalten Zementation, Dolomitisierung, Verkieselung und Bildung
von Porenräumen. Stabile Sauerstoffisotope ergaben für das Hamzeh-Ali-Profil
durchschnittliche Paläotemperaturen von 28°C und für das Shalamzar-Profil 22°C. Mittels
organischer Kohlenstoffuntersuchungen konnten drei diagenetische Pfade ermittelt werden:
Im Hamzeh-Profilwurden die meisten Proben von mariner Diagenese beeinflusst, einige auch
von flacher Versenkungsdiagenese. Proben des Shalamzar-Profils zeigen den Einfluß von
mariner bis Versenkungsdiagenese. ImSoh-Profil wurden die meisten Proben von flacher
Versenkungsdiagenese, einige Proben auch von meteorischer Diagenese überprägt. ImZefreh-
Profil weisen alle Proben Anzeichen von flacher Versenkungsdiagenese
auf.Strontiumisotopenuntersuchungen stellen das Hamzeh-Ali-Profil chronostratigraphisch in
das Cuisium und Lutetium, während das Shalamzar-Profil dem Lutetium zugeordnet werden
konnte. Das Zefreh-Profil gehört demnach in das Rupelium und das Soh-Profil in das
Priabonium‒Rupelium.

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Acknowledgements

I want to express my deep gratitude to Prof. Dr. Franz Theodor Fürsich (Geozentrum
Nordbayern der Universität Erlangen), for his supervision, fruitful discussions, scientific and
linguistic corrections, critical review and constructive comments on the manuscript. I am very
grateful to him for his kindness and hospitality and for providing many facilities during the
progress of my thesis.
Special thanks to Prof. Dr. Mohammad Hossein Adabi (Shahid Beheshti University, Iran)
for scientific guidance with respect to the sedimentary subjects and Dr. Ali Seyrafian
(Esfahan University, Iran) for help in field trips and gathering samples.
Special thanks to Dr. Seyed Ali Moallemi (Enhanced Oil Recovery Devision, Iran) for
identification of sequence stratigraphic patterns and stable isotopes analyses.
Special thanks to Prof. Dr. Michael Joachimski (Geozentrum Nordbayern der Universität
Erlangen) for his critical evaluation of the geochemical aspects of the thesis.
Special thanks to my ex-boss Mr. Homayoum Motiei (Retird employee of National Iranian
Oil Company, Iran) for helping to define this project and his valuable opinion.
Special thanks to Mr. Ebrahim Alavi Taleghani and Dr. Mohammad Ali Emadi (N.I.O.C)
for helping me to overcome my job problems.
I would like to thank all members of the Geozentrum Nordbayern, especially Prof. Dr.
Wolfgang Kiessling for his help and cooperation.
I also want to thank my colleagues at the National Iranian Oil Company especially, Mr.
Ravid Jalali.
Finally, I am deeply grateful to my mother (Maryam), my husband (Behnam) and my
daughter (Bita) for their patience and cooperation.

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Contents
1 Introduction ....................................................................................................................................................... 1
2 Regional Geology ............................................................................................................................................... 5
2.1 Geodynamic framework .............................................................................................................................. 6
2.2 Tertiary strata in Iran ................................................................................................................................... 7
2.3 Stratigraphy of the Zagros area ................................................................................................................. 10
2.4 Hydrocarbon significance of the major geological units of Iran ............................................................... 11
2.4.1 Central Iran ....................................................................................................................................... 11
2.4.2 The Alborz Mountains, northeastern basin, and Caspian Sea ........................................................... 12
2.4.3 The Zagros Mountains ...................................................................................................................... 12
2.5 Tectonic setting of the Zagros Mountains ................................................................................................. 13
2.5.1 Simply Folded Zone ......................................................................................................................... 13
2.5.2 Collision Zone .................................................................................................................................. 15
2.6 Sanandaj-Sirjan Zone ................................................................................................................................ 15
2.7 The stratigraphic succession of SW Iran ................................................................................................... 17
2.7.1 Palaeozoic ......................................................................................................................................... 19
2.7.2 Mesozoic........................................................................................................................................... 19
2.7.3 Cenozoic ........................................................................................................................................... 21
3 Material and methods ..................................................................................................................................... 22
4 The sections ...................................................................................................................................................... 23
4.1 Bouldaji section (Hamzeh- Ali Mountain) (co-ordinates: N 31°56'21'', E 51°00'11'') .............................. 23
4.2 Shalamzar section (co-ordinates: N31°59'4'', E50°51'48'') ....................................................................... 26
4.3 Zefreh section (co-ordinates: N 32°54΄55'', E 52°15΄55'') ........................................................................ 30
4.4 Soh section (co-ordinates: N32°28'24'', E51°28'22'') ................................................................................ 34
4.5 Lithostratigraphy columns ........................................................................................................................ 38
5 Diagenesis and cathodoluminescence studies ................................................................................................ 43
5.1 Marine phreatic diagenetic environment ................................................................................................... 45
5.2 Meteoric diagenetic environment .............................................................................................................. 45
5.3 Burial diagenetic environment .................................................................................................................. 45
5.4 Diagenetic processes affecting the Jahrum Formation .............................................................................. 47
5.4.1 Bioturbation ...................................................................................................................................... 47
5.4.2 Micritization ..................................................................................................................................... 47
5.4.3 Cementation ...................................................................................................................................... 47
5.4.4 Neomorphism ................................................................................................................................... 51
5.4.5 Dissolution ........................................................................................................................................ 51
5.4.6 Compaction ....................................................................................................................................... 52
5.4.7 Porosity ............................................................................................................................................. 52
5.4.8 Dolomitization .................................................................................................................................. 55
5.4.9 Fracturing ......................................................................................................................................... 55
5.5 Diagenetic processes in the Zagros area (Shalamzar and Hamzeh-Ali sections) ...................................... 55
5.6 Diagenetic processes in the Sanandaj-Sirjan Zone (Soh and Zefreh sections) .......................................... 55
6 Stable isotope analyses .................................................................................................................................... 65
6.1 Methods .................................................................................................................................................... 65
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6.2. Results ...................................................................................................................................................... 67
6.3 Paleotemperature determination ................................................................................................................ 67
6.3.1 Significance of δ18O values .............................................................................................................. 68
6.4 Diagenetic history of carbonate samples studied ...................................................................................... 69
6.4.1 Hamzeh-Ali section .......................................................................................................................... 69
6.4.2 Shalamzar section ............................................................................................................................. 71
6.4.3 Zefreh section ................................................................................................................................... 73
6.4.4 Soh section ........................................................................................................................................ 74
6.4.5 Sanandaj-Sirjan Zone ....................................................................................................................... 75
6.5 Strontium isotopes..................................................................................................................................... 75
6.5.1 Method of study ................................................................................................................................ 75
6.5.2 Age determination based on strontium isotopes ............................................................................... 76
6.5.3 Results .............................................................................................................................................. 77
6.6 Conclusions ............................................................................................................................................... 85
7 Microfacies and sedimentary environments .................................................................................................. 86
7.1 Biofacies types .......................................................................................................................................... 86
7.1.1 Carbonate mudstone (Facies 1) ........................................................................................................ 86
7.1.2 Planktonic foraminifera — operculinid — discocyclinid mudstone to wackestone (Facies 2) ........ 87
7.1.3 Planktonic foraminiferal wackestone to packstone with nummulitids and discocyclinids (Facies 3)
.......................................................................................................................................................... 87
7.1.4 Bioclastic wackestone—packstone (Facies 4) .................................................................................. 87
7.1.5 Bioclastic peloidal packstone to grainstone (Facies 5) ..................................................................... 89
7.1.6 Bioclastic (miliolid—coral—corallinacean) floatstone to rudstone (Facies 6) ................................. 89
7.1.7 Peloidal bioclastic (nummulitid—alveolinid) wackestone to packstone (Facies 7) .......................... 89
7.1.8 Bioclastic (small rotaliid—miliolid) peloidal wackestone to packstone (Facies 8) .......................... 90
7.1.9 Bioclastic (imperforate foraminifera) peloidal wackestone to packstone (Facies 9) ........................ 90
7.1.10 Alveolina—Coskinolina—Dictyoconus wackestone to packstone (Facies 10)................................ 91
7.1.11. Orbitolites wackestone to packstone (Facies 11) ........................................................................... 91
7.1.12 Charophyte mudstone to wackestone (Facies 12) ........................................................................... 91
7.1.13 Stromatolitic boundstone (Facies 13) ............................................................................................. 91
7.1.14 Conglomerates and breccia (Facies 14) .......................................................................................... 91
7.1.15 Sandstones (Facies 15) ................................................................................................................... 93
7.1.16 Siltstone (Facies 16) ....................................................................................................................... 94
7.1.17 Red mudstone (Facies 17) .............................................................................................................. 94
7.2 Sandstone petrography of the Soh section ................................................................................................ 94
7.3 Biofacies distribution in the Jahrum Formation of the Zagros Mountains ................................................ 95
7.4. Sequence stratigraphy .............................................................................................................................. 99
7.4.1 Sequence stratigraphy of the Zagros sections (Hamzeh-Ali and Shalamzar) (Figs. 7.3, 4) ............ 100
7.4.2 Sequence stratigraphy of the Sanandaj-Sirjan Zone (Soh and Zefreh sections) (Figs. 7.5, 6) ........ 103
7.4.3 Sequence stratigraphic correlation of the Zagros area (Hamzeh-Ali and Shalamzar sections)....... 105
7.4.4 Sequence stratigraphic correlation of the Sanandaj-Sirjan Zone (Soh and Zefreh sections) .......... 106
7.4.5 Interpretation of the depositional sequences of the Zagros area ..................................................... 115
7.4.6 Interpretation of the depositional sequences of the Sanandaj-Sirjan Zone ..................................... 115
8 Depositional model ........................................................................................................................................ 125
8.1 Hamzeh-Ali and Shalamzar sections....................................................................................................... 126
8.2 Soh area (Sanandaj‒Sirjan Zone) ............................................................................................................ 127
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8.3 Zefreh area (Sanandaj‒Sirjan Zone) ....................................................................................................... 128
9 Bio- and lithostratigraphy ............................................................................................................................. 130
9.1 Biostratigraphy of the Tethyan Paleocene and Eocene based on Larger Benthic Foraminifera.............. 130
9.2 Stratigraphy of the Eocene sequence ...................................................................................................... 132
9.2.1 Lithostratigraphy of the Jahrum Formation .................................................................................... 132
9.2.2 Biostratigraphic subdivisions .......................................................................................................... 134
9.3. Biostratigraphically defined boundaries of the Jahrum Formation (Zagros) and the Eocene sediments of
the Sanandaj-Sirjan Zone ........................................................................................................................ 140
9.4 SBZ foraminiferal biozonation ............................................................................................................... 142
10 Taxonomy of the foraminifera .................................................................................................................... 143
10. 1 Benthic foraminifera ............................................................................................................................ 143
10.2 Planktonic foraminifera ......................................................................................................................... 171
11 Conclusions .................................................................................................................................................. 199
12 References .................................................................................................................................................... 202
Appendix I ......................................................................................................................................................... 226
Appendix II ....................................................................................................................................................... 234

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