- Email: [email protected]
Organic Facies Characteristics of the Triassic Kasımlar Formation, Anamas-Akseki Platform, Western Taurides, Turkey
Available online at www.sciencedirect.com
ScienceDirect Energy Procedia 59 (2014) 150 – 157
European Geosciences Union General Assembly 2014, EGU 2014
2UJDQLFIDFLHVFKDUDFWHULVWLFVRIWKH7ULDVVLF.DVÕPODU)RUPDWLRQ Anamas-Akseki Platform, western Taurides, Turkey Selin Hokereka *, Neslihan Unala, Mehmet Altunsoya, Orhan Ozcelika, Mustafa Kuscub a
Department of Geological Engineering, Akdeniz University, Antalya,07058, Turkey Department of Geological Engineering, Süleyman Demirel University, Isparta, 32000, Turkey
b
Abstract In the Anamas-$NVHNLSODWIRUP 6:7XUNH\ WKH7ULDVVLF.DVÕPODU)RUPDWLRQFRQVLVWVRIELWXPLQRXVVKDOHDQGEHGGHGUHHIDO OLPHVWRQHV 'HWDLOHG GDWD IURP WKLFN 7ULDVVLF VHGLPHQWV .DVÕPODU )RUPDWLRQ PDGH LW SRVVLEOH WR FRQVWUXFW DQ RUJDQLF IDFLHV framework using different zonations. Organic matter is composed predominantly of woody material, with a minor contribution of planty and amorphous material. Kerogen in the deposits is type III, as indicated by organic petrographic observations and RockEval data. Total organic carbon (TOC) values are generally between 0.02 and 0.96%, but reach 3.78% in the formation. Tmax values vary between 284 and 454°C, confirming the increase in maturation trends indicated by vitrinite reflectance data. Organic facies type D was identified in the investigated units. Organic facies D is related to shale and carbonate lithofacies. This facies is characterized by average values of HI around 19 (equivalent to type III kerogene), TOC around 0.51%, and an average of S2 of 0.04 mg HC/g of rock. Organic facies D is nongenerative; the organic matter is highly oxidized, decomposed and reworked. © 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license © 2014 The Authors. Published by Elsevier Ltd. (http://creativecommons.org/licenses/by-nc-nd/3.0/). Peer-reviewunder under responsibility of the Austrian Academy of Sciences. Peer-review responsibility of the Austrian Academy of Sciences Keywords: Western Taurus Belt; Akseki-Anamas Platform; organic facies; organic geochemistry; organic petrography
1. Introduction The study area is located in the western part of the Taurus Belt (SW Turkey), known as “the Isparta Angle.” This region exhibits a complex structure involving two autochthonous units surrounded with the allochtonous complexes. 7KHDXWRFKWKRQRXVXQLWVDUHSDUWVRIWKH%H\GD÷ODUÕPLFUR-plate to the west and of the Anatolian micro-plate to the
* Corresponding author. Tel.: +90-242-310-4307; fax:+90-242-310-6306. E-mail address: [email protected]
1876-6102 © 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/). Peer-review under responsibility of the Austrian Academy of Sciences doi:10.1016/j.egypro.2014.10.361
Selin Hokerek et al. / Energy Procedia 59 (2014) 150 – 157
east (Anamas-Akseki platform). The Anamas-Akseki platform represents the SW margin of the Anatolian microplate located to the NE of the Isparta Angle )LJ .
)LJ6LPSOLILHGJHRORJLFDOPDSRIWKH,VSDUWD$QJOHDQGVXUURXQGLQJDUHDV PRGLILHGIURP [1], [2], [3]).
This platform is also composed of shallow marine carbonates and clastic sediments from Triassic up to Eocene age. In these units, organic materials are observed LQ WKH .DVÕPODU )RUPDWLRQ )LJ . This formation consists of dark-grey bituminous shale and bedded blackish reefal limestones )LJ .
151
152
Selin Hokerek et al. / Energy Procedia 59 (2014) 150 – 157
. )LJ*HRORJLFDOPDSRIWKHLQYHVWLJDWHGDUHD.
Previous studies of this region have defined and described the rock units, sedimentary associations, stratigraphy, tectonics and petroleum geology. General geological investigations and reports have been presented by [4], [5], [6], [7], [8], [9], [10,11], [12], [13] and [14], who studied the sedimentological character and tectonics of the study area and environs. Petroleum-geological studies have also been carried out; important ones include the works of [15], [16,17] and [18@ ,Q WKLV VWXG\ ZH GHVFULEH RUJDQLF IDFLHV FKDUDFWHULVWLFV RI WKH 7ULDVVLF .DVÕPODU )RUPDWLRQ sediments of the Akseki-Anamas Platform in the western Taurides. In order to determine the amounts, types and maturation of organic matter in these strata, outcrop samples of carbonates and shale were collected.
Selin Hokerek et al. / Energy Procedia 59 (2014) 150 – 157
)LJ*HQHUDOL]HGVWUDWLJUDSKLFVXFFHVVLRQLQWKHLQYHVWLJDWHGDUHD.
2. Organic facies investigations The Triassic bituminous units have been investigated with respect to organic facies characteristics. About 60 outcrop samples were collected from the .DVÕPODU)RUPDWLRQ)RUDQDO\VLV, the selection of samples was primarily based on changes in colour, type of lithology and other sedimentary characteristics. In order to determine the facies and mature of the organic matter, a number of organic petrographic and geochemical analyses were made upon the kerogen isolated from the hole samples. Total organic carbon (TOC) and pyrolysis analyses were realized by the Turkish Petroleum Research Center (Ankara-Turkey) using Rock Eval VI DQDO\]HU DFFRUGLQJ WR ,)3 ,QVWLWXW
153
154
Selin Hokerek et al. / Energy Procedia 59 (2014) 150 – 157
)UDQFDLVGX3HWUROH VWDQGDUG Other microscopic studies were also carried out at the Akdeniz University (AntalyaTurkey) and Turkish Petroleum Research Center (Ankara-Turkey). Total organic carbon values were measured on 28 samples from the Triassic bituminous units (Table 1). The obtained data show that the total organic carbon values are between 0.02% and 3.78%, with an average around 0.51%. Table 1 illustrates the values of total organic carbon, Rock-Eval pyrolysis results of the samples. In the Triassic bituminous sediments, the hydrogen index range from 2 to 150 mgHC/gTOC, with an average around 19 mgHC/gTOC. Table 1. Total organic carbon and Rock-Eval pyrolysis results of study area.
The Production index (PI) range from 0.04 to 0.63, with an average of 0.28 and Tmax range from 284°C to 454°C, with an average of 373°C. Organic geochemical measurements of samples were plotted on a hydrogen index Tmax GLDJUDP )LJ). The results indicate that the samples contain Type III kerogen.
Selin Hokerek et al. / Energy Procedia 59 (2014) 150 – 157
)LJ Classification of the kerogen types by Hyrogen Index vs. Tmax (°C) diagram.
Organic petrographic analysis, including reflected white light examination of organic matter concentrates and polished section of whole rock, was carried out using coal petrographic techniques. Measurements of vitrinite reflectance were made to characterize thermal maturity of the organic matter. Vitrinite reflection values were measured on 15 samples taken from the Triassic units (Table 2). The samples showed vitrinite reflectance values averaging 2.01% (ranging from 1.3 to 2.7) (Table 2). According to the microscopical observations, kerogens are dominated by woody organic matter (93%) and a little amorphous (6%) and planty (1%) organic matter. Jones and Demaison [19] proposed a formal definition, where an “organic facies is a detectable subdivision of a certain stratigraphic unit which can be discriminated by the characteristics of the organic constituents without considering the aspects of the inorganic fraction of the sediments”. Organic facies classification proposed by Jones [20] was used to evaluate organic facies. As a result, we were able to differentiate only one organic facies type. This organic facies was type D. The D facies consists of highly decomposed, reworked organic matter. These types of organic facies generally appear to be weakly sorted in marine and lake sediments.
155
156
Selin Hokerek et al. / Energy Procedia 59 (2014) 150 – 157 Table 2. Organic matter type and vitrinite (Ro) values of investigated samples. Location No of Samples
Sample No
Amorphous (%)
Herbaceous (%)
Woody (%)
Coaly (%)
Ro (%)
5
KS04
-
-
100
-
n.d.
8
KS08B
-
-
100
-
2.7
9
KS09
-
-
100
-
n.d.
12
KS12
-
-
100
-
n.d.
14
KS14B
-
-
100
-
n.d.
15
KS15
-
-
100
-
2.2
16
KS16A
-
-
100
-
n.d.
KS16B
80
-
20
-
n.d
17
KS17
-
5
95
-
n.d
18
KS18
-
-
100
-
2.7
19
KS19
-
-
100
-
n.d.
20
KS20B
80
-
20
-
n.d.
21
KR01
-
-
100
-
2.5
22
KR02
-
-
100
-
2.6
23
KR03B
-
-
100
-
2.4
24
KR04A
-
-
100
-
2.3
25
KR05
-
-
100
-
n.d.
27
KR07
-
-
-
-
2.6
28
KR08
-
-
100
-
2.5
n.d.:not detected
4. Conclusions The aim of this study is to determine organic facies characteristics of Triassic units located on the AnamasAkseki platform. The .DVÕPODUIRUPDWLRQZDVHYDOXDWHGusing organic geochemical and petrographic analysis with respect to the aim of this study. Total organic carbon contents in the bore samples indicate that the bituminous Triassic units have enough organic matter indicating hydrocarbon source rock. This unit has hydrogen index values (2-150 mgHC/gTOC) mostly characteristic of Type III kerogen. Rock-Eval Tmax and Production index values are about 373°C and less than 0.3 respectively. Organic facies D is related to shale and carbonate lithofacies. Organic facies D is nongenerative; the organic matter is highly oxidized, decomposed and reworked. It can be said that the VDPSOHVRI.DVÕPODUIRUPDWLRQKDYHEHHQdeposited in the organic facies D. Acknowledgements The authors would like to thank Research Unit of the Akdeniz University and Turkish Petroleum Corporation (TPAO) (Turkey) foundation.
References [1] ùenel M. Discussion on the Antalya nappes. In: 7HNHOL2*|QFR÷lu MC, editors. Geology of Taurus Belt - Proceedings of International Symposium on the Geology of the Taurus Belt. Mineral Research and Exploration Institute (MTA) of Turkey Publication.1984;41-52. >@3RLVVRQ$$ND\('XPRQW-)8\VDO67KH,VSDUWD$QJOH $0HVR]RLFSDOHRULIWLQWKH:HVWHUQ7DXULGHV,Q 7HNHOL2*|QFR÷OX0& editors. International Symposium on Geology of the Taurus Belt (Proceedings Book), Ankara, Turkey, September 26-29, 1984;11-26.
Selin Hokerek et al. / Energy Procedia 59 (2014) 150 – 157 [3] @-RQHV5:'HPDLVRQ*-2UJDQLF)DFLHV- stratigraphic concepts and exploration tool. In: Saldivar-Sali A, editor. Proceedings of the Second ASCOPE Conference and Exhibition,Manilla, Asean Council on Petroleum; 1982. p.51-68. >@-RQHV5:2UJDQLF)DFies. In: Brooks J., Welte D. editors. Advances in Petroleum Geochemistry, Academic Press, London, 1987; 2:1-90.
157
ScienceDirect Energy Procedia 59 (2014) 150 – 157
European Geosciences Union General Assembly 2014, EGU 2014
2UJDQLFIDFLHVFKDUDFWHULVWLFVRIWKH7ULDVVLF.DVÕPODU)RUPDWLRQ Anamas-Akseki Platform, western Taurides, Turkey Selin Hokereka *, Neslihan Unala, Mehmet Altunsoya, Orhan Ozcelika, Mustafa Kuscub a
Department of Geological Engineering, Akdeniz University, Antalya,07058, Turkey Department of Geological Engineering, Süleyman Demirel University, Isparta, 32000, Turkey
b
Abstract In the Anamas-$NVHNLSODWIRUP 6:7XUNH\ WKH7ULDVVLF.DVÕPODU)RUPDWLRQFRQVLVWVRIELWXPLQRXVVKDOHDQGEHGGHGUHHIDO OLPHVWRQHV 'HWDLOHG GDWD IURP WKLFN 7ULDVVLF VHGLPHQWV .DVÕPODU )RUPDWLRQ PDGH LW SRVVLEOH WR FRQVWUXFW DQ RUJDQLF IDFLHV framework using different zonations. Organic matter is composed predominantly of woody material, with a minor contribution of planty and amorphous material. Kerogen in the deposits is type III, as indicated by organic petrographic observations and RockEval data. Total organic carbon (TOC) values are generally between 0.02 and 0.96%, but reach 3.78% in the formation. Tmax values vary between 284 and 454°C, confirming the increase in maturation trends indicated by vitrinite reflectance data. Organic facies type D was identified in the investigated units. Organic facies D is related to shale and carbonate lithofacies. This facies is characterized by average values of HI around 19 (equivalent to type III kerogene), TOC around 0.51%, and an average of S2 of 0.04 mg HC/g of rock. Organic facies D is nongenerative; the organic matter is highly oxidized, decomposed and reworked. © 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license © 2014 The Authors. Published by Elsevier Ltd. (http://creativecommons.org/licenses/by-nc-nd/3.0/). Peer-reviewunder under responsibility of the Austrian Academy of Sciences. Peer-review responsibility of the Austrian Academy of Sciences Keywords: Western Taurus Belt; Akseki-Anamas Platform; organic facies; organic geochemistry; organic petrography
1. Introduction The study area is located in the western part of the Taurus Belt (SW Turkey), known as “the Isparta Angle.” This region exhibits a complex structure involving two autochthonous units surrounded with the allochtonous complexes. 7KHDXWRFKWKRQRXVXQLWVDUHSDUWVRIWKH%H\GD÷ODUÕPLFUR-plate to the west and of the Anatolian micro-plate to the
* Corresponding author. Tel.: +90-242-310-4307; fax:+90-242-310-6306. E-mail address: [email protected]
1876-6102 © 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/). Peer-review under responsibility of the Austrian Academy of Sciences doi:10.1016/j.egypro.2014.10.361
Selin Hokerek et al. / Energy Procedia 59 (2014) 150 – 157
east (Anamas-Akseki platform). The Anamas-Akseki platform represents the SW margin of the Anatolian microplate located to the NE of the Isparta Angle )LJ .
)LJ6LPSOLILHGJHRORJLFDOPDSRIWKH,VSDUWD$QJOHDQGVXUURXQGLQJDUHDV PRGLILHGIURP [1], [2], [3]).
This platform is also composed of shallow marine carbonates and clastic sediments from Triassic up to Eocene age. In these units, organic materials are observed LQ WKH .DVÕPODU )RUPDWLRQ )LJ . This formation consists of dark-grey bituminous shale and bedded blackish reefal limestones )LJ .
151
152
Selin Hokerek et al. / Energy Procedia 59 (2014) 150 – 157
. )LJ*HRORJLFDOPDSRIWKHLQYHVWLJDWHGDUHD.
Previous studies of this region have defined and described the rock units, sedimentary associations, stratigraphy, tectonics and petroleum geology. General geological investigations and reports have been presented by [4], [5], [6], [7], [8], [9], [10,11], [12], [13] and [14], who studied the sedimentological character and tectonics of the study area and environs. Petroleum-geological studies have also been carried out; important ones include the works of [15], [16,17] and [18@ ,Q WKLV VWXG\ ZH GHVFULEH RUJDQLF IDFLHV FKDUDFWHULVWLFV RI WKH 7ULDVVLF .DVÕPODU )RUPDWLRQ sediments of the Akseki-Anamas Platform in the western Taurides. In order to determine the amounts, types and maturation of organic matter in these strata, outcrop samples of carbonates and shale were collected.
Selin Hokerek et al. / Energy Procedia 59 (2014) 150 – 157
)LJ*HQHUDOL]HGVWUDWLJUDSKLFVXFFHVVLRQLQWKHLQYHVWLJDWHGDUHD.
2. Organic facies investigations The Triassic bituminous units have been investigated with respect to organic facies characteristics. About 60 outcrop samples were collected from the .DVÕPODU)RUPDWLRQ)RUDQDO\VLV, the selection of samples was primarily based on changes in colour, type of lithology and other sedimentary characteristics. In order to determine the facies and mature of the organic matter, a number of organic petrographic and geochemical analyses were made upon the kerogen isolated from the hole samples. Total organic carbon (TOC) and pyrolysis analyses were realized by the Turkish Petroleum Research Center (Ankara-Turkey) using Rock Eval VI DQDO\]HU DFFRUGLQJ WR ,)3 ,QVWLWXW
153
154
Selin Hokerek et al. / Energy Procedia 59 (2014) 150 – 157
)UDQFDLVGX3HWUROH VWDQGDUG Other microscopic studies were also carried out at the Akdeniz University (AntalyaTurkey) and Turkish Petroleum Research Center (Ankara-Turkey). Total organic carbon values were measured on 28 samples from the Triassic bituminous units (Table 1). The obtained data show that the total organic carbon values are between 0.02% and 3.78%, with an average around 0.51%. Table 1 illustrates the values of total organic carbon, Rock-Eval pyrolysis results of the samples. In the Triassic bituminous sediments, the hydrogen index range from 2 to 150 mgHC/gTOC, with an average around 19 mgHC/gTOC. Table 1. Total organic carbon and Rock-Eval pyrolysis results of study area.
The Production index (PI) range from 0.04 to 0.63, with an average of 0.28 and Tmax range from 284°C to 454°C, with an average of 373°C. Organic geochemical measurements of samples were plotted on a hydrogen index Tmax GLDJUDP )LJ). The results indicate that the samples contain Type III kerogen.
Selin Hokerek et al. / Energy Procedia 59 (2014) 150 – 157
)LJ Classification of the kerogen types by Hyrogen Index vs. Tmax (°C) diagram.
Organic petrographic analysis, including reflected white light examination of organic matter concentrates and polished section of whole rock, was carried out using coal petrographic techniques. Measurements of vitrinite reflectance were made to characterize thermal maturity of the organic matter. Vitrinite reflection values were measured on 15 samples taken from the Triassic units (Table 2). The samples showed vitrinite reflectance values averaging 2.01% (ranging from 1.3 to 2.7) (Table 2). According to the microscopical observations, kerogens are dominated by woody organic matter (93%) and a little amorphous (6%) and planty (1%) organic matter. Jones and Demaison [19] proposed a formal definition, where an “organic facies is a detectable subdivision of a certain stratigraphic unit which can be discriminated by the characteristics of the organic constituents without considering the aspects of the inorganic fraction of the sediments”. Organic facies classification proposed by Jones [20] was used to evaluate organic facies. As a result, we were able to differentiate only one organic facies type. This organic facies was type D. The D facies consists of highly decomposed, reworked organic matter. These types of organic facies generally appear to be weakly sorted in marine and lake sediments.
155
156
Selin Hokerek et al. / Energy Procedia 59 (2014) 150 – 157 Table 2. Organic matter type and vitrinite (Ro) values of investigated samples. Location No of Samples
Sample No
Amorphous (%)
Herbaceous (%)
Woody (%)
Coaly (%)
Ro (%)
5
KS04
-
-
100
-
n.d.
8
KS08B
-
-
100
-
2.7
9
KS09
-
-
100
-
n.d.
12
KS12
-
-
100
-
n.d.
14
KS14B
-
-
100
-
n.d.
15
KS15
-
-
100
-
2.2
16
KS16A
-
-
100
-
n.d.
KS16B
80
-
20
-
n.d
17
KS17
-
5
95
-
n.d
18
KS18
-
-
100
-
2.7
19
KS19
-
-
100
-
n.d.
20
KS20B
80
-
20
-
n.d.
21
KR01
-
-
100
-
2.5
22
KR02
-
-
100
-
2.6
23
KR03B
-
-
100
-
2.4
24
KR04A
-
-
100
-
2.3
25
KR05
-
-
100
-
n.d.
27
KR07
-
-
-
-
2.6
28
KR08
-
-
100
-
2.5
n.d.:not detected
4. Conclusions The aim of this study is to determine organic facies characteristics of Triassic units located on the AnamasAkseki platform. The .DVÕPODUIRUPDWLRQZDVHYDOXDWHGusing organic geochemical and petrographic analysis with respect to the aim of this study. Total organic carbon contents in the bore samples indicate that the bituminous Triassic units have enough organic matter indicating hydrocarbon source rock. This unit has hydrogen index values (2-150 mgHC/gTOC) mostly characteristic of Type III kerogen. Rock-Eval Tmax and Production index values are about 373°C and less than 0.3 respectively. Organic facies D is related to shale and carbonate lithofacies. Organic facies D is nongenerative; the organic matter is highly oxidized, decomposed and reworked. It can be said that the VDPSOHVRI.DVÕPODUIRUPDWLRQKDYHEHHQdeposited in the organic facies D. Acknowledgements The authors would like to thank Research Unit of the Akdeniz University and Turkish Petroleum Corporation (TPAO) (Turkey) foundation.
References [1] ùenel M. Discussion on the Antalya nappes. In: 7HNHOL2*|QFR÷lu MC, editors. Geology of Taurus Belt - Proceedings of International Symposium on the Geology of the Taurus Belt. Mineral Research and Exploration Institute (MTA) of Turkey Publication.1984;41-52. >@3RLVVRQ$$ND\('XPRQW-)8\VDO67KH,VSDUWD$QJOH $0HVR]RLFSDOHRULIWLQWKH:HVWHUQ7DXULGHV,Q 7HNHOL2*|QFR÷OX0& editors. International Symposium on Geology of the Taurus Belt (Proceedings Book), Ankara, Turkey, September 26-29, 1984;11-26.
Selin Hokerek et al. / Energy Procedia 59 (2014) 150 – 157 [3]
157