Indonesian Journal on Geoscience Vol. 7 No. 1 April 2020: 15-24

INDONESIAN JOURNAL ON GEOSCIENCE Geological Agency Ministry of Energy and Mineral Resources

Journal homepage: hp://ijog.geologi.esdm.go.id ISSN 2355-9314, e-ISSN 2355-9306

Nannofossil Distribution and Age of Kendeng Zone In Kalibeng River Section of Kedungringin, Plandaan Area, Jombang, East

1 1 2 1 Siti Umiyatun Choiriah , Carolus Prasetyadi , Rubiyanto Kapid , and Dwi Fitri Yudiantoro

1Geological Engineering, Faculty of Mineral Technology UPN “Veteran” Yogyakarta,

2 Jln. SWK 104, Condongcatur, Kabupaten Sleman, Daerah Istimewa Yogyakarta Geological Engineering, Faculty of Earth Sciences and Technology, Bandung Institute of Technology (ITB) Jln. Ganesha No. 10, Bandung, Indonesia

Corresponding author: [email protected]; [email protected] Manuscript received: October, 20, 2016; revised: December, 19, 2016; approved: September, 05, 2019; available online: January, 21, 2020

Abstract - This study was carried out at Kalibeng River Section, in Kedungringin area, a site with lithology suitable for a nannoplankton research. Methods used in this research include performing a stratigraphical measurement section at the field, collecting thirty-two samples, and preparing the samples with the smear slide method using a polarizing microscope with 1000x magnification, and preparing several rock samples using SEM analysis. The analysis of nannofossil resulted in twelve genera and forty-three species. The identified genera are: Calcidiscus, Coccolithus, Ceratolithus, Discoaster, Gephyrocapsa, Helicosphaera, Pseudoemiliania, Reticulofenestra, Rhabdosphaera, Sphe- nolithus, Syracosphaera, and Umbilicosphaera. The presence of these genera indicates that Kalibeng River Section have abundant nannofossils and based on the nannofossil analysis, from older to younger, the studied stratigraphic sequence indicates a more detailed age determination as follows: the Marl Unit of Kalibeng is NN10-NN18 (Middle Miocene to Pliocene), Calcareous Sandstone Unit of Sonde is NN19-NN20 (Pliocene-Pleistocene), and Calcareous Claystone Unit of Sonde is NN20-NN21 (Pleistocene). Keywords: calcareous fine clastics, nannoplankton, Miocene to Pleistocene, Kendeng © IJOG - 2020. All right reserved

How to cite this article: Choiriah, S.U., Prasetyadi, C., Kapid, R., and Yudiantoro, D.F., 2020. Nannofossil Distribution and Age of Kendeng Zone In Kalibeng River Section of Kedungringin, Plandaan Area, Jombang, Data. Indonesian Journal on Geoscience, 7 (1), p.15-24. DOI: 10.17014/ijog.7.1.15-24

Introduction reconstruction of paleobiogeographic (Van Gor- sel et al., 2014). Background The stratigraphic analysis shows that the Research of fossil is one of the most impor- Kendeng Zone is a young fold-thrust belt, which tant tools for the studyIJOG of sedimentary rocks was only active within the Pliocene. In this zone, and basins. First, the succession of evolution- deep marine volcaniclastic sediments of Early ary appearances and extinctions provides age Pliocene and older ages have been uplifted and control, which is critical for understanding basin thrusted northwards since mid-Pliocene time evolution and validation of geological concepts. (Lunt, 2013, in Berghuis et al., 2019). Second, fossils are useful for interpretation of The Kendeng Zone is the southern part of East local paleoenvironment, paleoclimate, and also Java basinal system. The sedimentary evolution

Accredited by: RISTEKDIKTI (1st grade), valid August 2016 - April 2020 Indexed by: SCOPUS (Q3) 15 Indonesian Journal on Geoscience, Vol. 7 No. 1 April 2020: 15-24 of this basin indicates that the East Java basinal claystone, tuff, and sandstone {with Klitik Mem- system was formed as a continuation of extension ber (Tpk) consisting of limestone}; Pucangan around the Makassar Strait to the east, and not as Formation (Qtp), composed of tuffaceous breccia, a back-arc basin. This interpretation is based on conglomerate, and tuffaceous Sandstone; Kabuh tectonically pulsed east to west trend in crustal Formation (Qpk), consisting of coarse tuffaceous thinning, subsidence, and trans-gression (Lunt, sandstone with cross-bedding sedimentary struc- 2019) ture, claystone, and conglomerate; and Notopuro The studied area is occupied by a sedimenta- Formation (Qpn), comprising tuff, interbedded tion sequence consisting mostly of fine-grained with tuffaceous sandstone, volcanic breccia, and marine sedimentary rocks that contain abundant conglomerate (Figure 1). microfossils with the age from Miocene to Qua- Sedimentary rocks found in the studied area ternary. A nannoplankton research in the Kendeng contain a large amount of microfossils, including Zone has been done by Choiriah et al. (2001), but nannoplankton which is very valuable to support only limited to the Bengawan Solo River in the objective of this study. Nannofossil is a kind Ngawi. The results of previous study in Ngawi of algae which belongs to the Haptophyceae class section show that the nannofossil contained with a tiny size (0.5-10 µm). In the living state, within Kalibeng Formation consists of eighteen this organism has planktonic characteristics. genera and forty-nine species, while Klitik/ Sonde Formation has eight genuses and twelve species. The age of Kalibeng Formation is Late Materials And Methods Miocene to Late Pliocene (NN12-NN18), and Klitik (Sonde) Formation is of Early Pleistocene Field Data Sampling (NN19-NN20) This step consists of making a measurement The purpose of this study is to determine the section and detailed rock sampling to better distribution and the age of the youngest marine understand the changing and development of sediments in Kendeng Zone based on nannofossil nannoplankton, as well as determining the age found in the Kalibeng River Section, and to cor- of each rock layer (Figure 2). relate it to the similar result of the Ngawi Section. A large amount of nannofossils was collected from a small sample due to its tiny size. Rock Stratigraphic Setting samples that contain the fossils can be obtained The studied area, which is part of Kalibeng from outcrop, drill core, or cutting. River in the Kedungringin and surrounding area, Plandaan Subregency, Jombang, East Java, is Laboratory Analysis situated in the Kendeng Zone. This part of the Equipments needed for the analysis include river is classified as the type locality of Kalibeng rock sample, prepared slides, coverglass, grinder, Formation since it is located in the Kalibeng River. dryer/oven, weter, pipette, entellan liquid (func- According to Pringgoprawiro (1983), the order of tions as glue), and labels. the lithostratigraphic formations in the Kendeng Nannoplankton is very small to identy mac- Zone, from the oldest to the youngest is as follows: roscopically, that is why an optical (polarizing) Pelang Formation (Tomp), composed of marl and microscope with a high magnification (1000 X), claystone with intercalationIJOG of calcarenite; Kerek or even Scanning Electron Microscope (SEM) is Formation (Tmk), comprising interbedded marl, needed. The nannofossil analysis was performed limestone, and sandstone; Kalibeng Formation using a polarizing microscope by making “smear (Tmpkk), consisting of marl with intercalations of slides” that could be prepared in a few minutes. sandstone {with Atasangin Member (Tmpa) made The nannofossil analysis was done using a up of breccia, sandstone, and claystone}; Sonde polarizing microscope with 1000x magnifica- Formation (Tpso), composed of marl, calcareous tion, in parallel and cross Nicol views. The

16 Nannofossil Distribution and Age of Kendeng Zone In Kalibeng River Section of Kedungringin, Plandaan Area, Jombang, East Java (S.U. Choiriah et al. )

AGE TION ADAM STRATIGRAPHY LITHOLOGY

ZONA (1970) DESCRIPTION (1969) FM MEMBER BLOW HOLOCENE Laharic breccia, tuff, tuffaceous sandstone; 0,5 N23 NOTOPURO (Qpn) fluviatile cross-bedded sandstone. PLEISTOCENE KABUH (Qpk) N22 PUCANGAN (Qtp) Volcanic conglomerate, sandstone, black claystone 2 Upper Marl, calcareous claystone, tuff, N21 sandstone with Balanus and mollusca

SONDE (Tpso) KLITIK Corraline limestone, bedded Globigerina PLIOCENE N20 (Tpk) limestone

Massive Globigerina marl with intercalations N19 ATAS ANGIN of graded sandstone, volcanic breccia, and tuff (Tmpa) (Tmpkk)

N18 KALIBENG (

Hard calcarenite, bedded calcarenite, N17 tuff, calcirudite Late N16 Tuff and agglomerate

Hard calcarenite 10 N15 Middle N14 Interbedded marl, claystone, and mudstone KEREK (Tmk) N13

N12

Middle N11 Tf

N10

N9 MIOCENE 20 Lower N8 )

N7 p

m Marl and claystone with calcarenite o

T intercalation of calcarenite with larger

N6 ( foraminifera Early G

20 N A

N5 L E P N4

P22 (N3) Te P21 (N2) 25 P20 (N1) OLIGOCENE P9 Lower

P14 Tcd

Figure 1. Stratigraphy of Kendeng Zone (modified after Pringgoprawiro, 1983). photomicrographs of fossils were taken using a microscope in Petrographic Laboratory UPN microscopic camera (Moticam) connected to a “Veteran” Yogyakarta and Scanning Electron. laptop or computer. The names of genus and spe- Microscope of Sedimentology Laboratory, ITB. cies were referencedIJOG from previous researchers (Martini, 1971; Okada and Bukry, 1980; Perch- Nielsen, 1985; Aubry, 1985). The appearance of Result and Analysis nannofossil species in each rock sample is the main data of this study. Stratigraphically, the Kalibeng River Section The photomicrographs of nannofossils within in the studied area is composed of Marl Unit of the researched area were taken using a polarizing Kalibeng Formation, Calcareous Sandstone Unit

17 Indonesian Journal on Geoscience, Vol. 7 No. 1 April 2020: 15-24

620000.000000 621000.000000 622000.000000 623000.000000 624000.000000

156.73 125

9178000 125 187.5 175 KABUPATEN JOMBANG 162.5 125 201.8 212.5 134.04 181.01 162.5 150 N 150 154.78 168.52 187.5 1 100 212.5 137.5 12.5 200 225 1 0 500 1.000 12.5 175 100 171.99 Meters 187.5 200 212.5 171.71 207.88 219.66 115.51 200

212.5 112.5 150 230.3 225 .000000

212.5 .000000

200 150 162.5 9177000 225 200 9177000 212.5 175 187.5 162.5 137.5

230.63 150 137.5 137.3

142.63 150

150 125 137.5 137.5 137.5 10 Klitih 125 D-1 126.81 137.5 13 134.33 14 125 138.75

137.5 18 150 .000000 156.27 .000000 D-2 125 125 137.5 137.5 137.5 12 14 D-3 75.47 75 16 145.17 75 9176000 D-4 125 9176000 50 Pule 12.5 1 Putuk 99.79 D-5 14 125 124.26 100 DESA KLITIH D-6 125 24 12.5 125 1 128.42 D-7 127.42 125 Klitih 125.15 116.23

D-8 87.5 118.55 100 50 D-9 50 D-10 120.17 116.47 125 Tondowesi 87.5 51.31 92.79 D-11 Nampu K. Beng 100

.000000 Kedungringin

136.15 .000000 100 D-12 21 62.5 Temple 9175000 73.1 9175000 D-13 62.5

D-14 61.46 150 137.5 D-15 D-16 166.74 D-17 112.74 98.3 87.5 DESA PULE 137.5 D-18 112.5 150 100 112.5 D-19 112.96 83.62 98.61

1 111.42 12.5 62.5 D-20

D-21 D-24Pule 100 12 87.5 100 15 50 .000000 D-22 97.51 .000000 19 12 100 D-23 111.25 16

9174000 18 104.38 D-25 11 11 9174000 Papringan 97.56 88.6 62.5 87.5 21 26 63.46 87.5 96.79 DESA PINGGIR 21 20 D-26 62.5 Ngepung 17 100 13 80.84 16 87.5 87.5 Perning 17 25 Pinggir D-27 Sumberbutak Pinggir D-28 D-29 1818 21 D-30 DESA PINGGIR26 19 104.82 D-31 D-32 100.7 78 26 .000000 82.27 112.5 18 100 16 114.28 D-33 9173000 620000.000000 621000.000000 622000.000000 623000.000000 624000.000000 UNIT LITHOLOGIC SYMBOLS : MAP INDEX :

Calcareous Claystone Unit of Sonde

Calcareous Sandstone Unit of Sonde Marl Unit of Kalibeng

Kedungringin, Sampling Location Jombang

Strike/Dip 19 D-24 Sample ID Sinistral Strik-slip Fault

Figure 2. Location of calcareous sediment sampling for the nannoplankton analysis within the background of the geological map of Kedungringin area.

of Sonde Formation, andIJOG Calcareous Claystone The nannofossils found in Marl Unit of Kali­ Unit of Sonde Formation (Figure 3). beng Formation are represented by sample D.1 to The analysis of nannofossil in the studied D.24 consisting of twelve genera with thirty-nine area reveals that within a total of thirty-three species (Table 1). samples of rock thirteen genera and forty-three They comprise Calcidiscus leptoporus, species of nannofossil (Table 1 and Figure 4) Ceratolithus acutus, Coccolithus pelagicus, are identified. Coccolithus pliopelagicus, Discoaster altus, Dis-

18 Nannofossil Distribution and Age of Kendeng Zone In Kalibeng River Section of Kedungringin, Plandaan Area, Jombang, East Java (S.U. Choiriah et al. )

Symbol of Description of Depositional

Unit Lithology Lithology Environment (1971) Epoch Martini Lithology Formation Thickness

Loose material from weathering and reworked of older rocks Alluvium sediment 12 m Holocene

Calcareous claystone Sonde, dominated by calcareous claystone with intercalation Lagoon 89,9 m of calcareous sandstone, claystone Calcareous calcareous siltstone, massive NN20-NN21 and lamination stuctures. Pleistocene

S Calcareous sandstone Sonde

Sonde dominated by calcareous sandstone with intercalation of calcareous claystone, Inner to

47,5 m limestone, and calcareous Middle Shelf siltstone. sandstone

Calcareous NN19-NN20

Marl of Kalibeng, consisting of marl dominated, massive structure with intercalation of Inner to calcarenite limestone, Middle 446,3 m calcareous sandstone, Bathyal lamination and load cast Marl sedimentary structures. Kalibeng NN10-NN18 Late Miocene to Pliocene

Figure 3. Stratigraphy of Kedungringin, Jombang, East Java. coaster asymmetricus,IJOG Discoaster blackstockae, triradiatus, Discoaster tristellifer, Discoaster Discoaster bolli, Discoaster brouweri, Dis- variabilis, Gephyrocapsa carribeanica, Ge- coaster calcaris, Discoaster druggii, Discoaster phyrocapsa oceanica, Helicosphaera carteri, challengeri, Discoaster hamatus, Discoaster Helicosphaera selli, Pseudoemiliania lacu- intercalaris, Discoaster neorectus, Discoaster nosa, Pseudoemiliania ovata, Reticulofenestra perplexus, Discoaster pentaradiatus, Discoaster haqii, Reticulofenestra minuta, Reticulofenestra quadramus, Discoaster surculus, Discoaster minutula, Reticulofenestra pseudoumbilicus,

19 Indonesian Journal on Geoscience, Vol. 7 No. 1 April 2020: 15-24

Table 1. Distribution of Nannofossils in Kalibeng River Section, Jombang Area

Calc. Calc. Marl Unit of Sandstone Claystone KALIBENG SONDE SONDE

NN20-NN21 Species NN19-NN20 Early NN10-NN18 Pliocene Pleistocene Miocene to Pliocene to Early to Late Pleistocene Pleistocene

No. Nannofossil D.1 D.2 D.3 D.4 D.5 D.6 D.7 D.8 D.9 D.10 D.11 D.12 D.13 D.14 D.15 D.16 D.17 D.18 D.19 D.20 D.21 D.22 D.23 D.24 D.25 D.26 D.27 D.28 D.29 D.30 D.31 D.32 D.33 1 Calcidiscus leptoporus ─ ─ ─ ─ ─ ─ o 2 Ceratolithus acutus ─ ─ ─ ─ 3 Coccolithus pelagicus ─ ● ─ ● ─ / / / ● o / ● ● ─ ● ─ ● ● ● ● 4 Coccolithus pliopelagicus ● ● ─ ● o ● o ● ● / / / / o / ● o ● / ─ o ● ● 5 Discoaster asymmetricus ─ ─ ● ● ● o o o ● ● ● ─ ─ ─ 6 Discoaster berggrenii ─ ● ● ─ ─ ─ ● ─ ● ● ● ─ o ─ 7 Discoaster blackstockae ─ ─ ─ 8 Discoaster brouweri ─ ● ● ● o ● ● ● ● o ● / o ● o o o o o / ─ 9 Discoaster chalengeri ● ─ ● ● ● ─ ─ ● 10 Discoaster hamatus ─ ● ● o ● ● ● ● 11 Discoaster intercalaris ─ ─ ● ─ ● ─ ● ─ ─ 12 Discoatser neorectus ─ ─ ● ─ ─ 13 Discoaster pentaradiatus ─ 14 Discoaster quinqueramus o ● ● o ● o o ● ─ ─ ● ─ ─ 15 Discoaster surculus ─ ─ ─ ─ ● ● ● ● ● ● ● ─ o 16 Discoaster triradiatus ● ● ─ ─ ● ─ ─ ─ 17 Discoaster tristellifer o ● ● ● / / o ─ ─ ● ● ● ● ● 18 Discoaster variabilis ─ ─ ● ─ ● ● ─ ─ ─ ─ 19 Gephyrocapsa carribeanica ─ ─ 20 Gephyrocapsa oceanica ─ ─ 21 Helicosphaera carteri ● ─ ● ● o ● o / ● ─ / ● o ─ ─ 22 Helicosphaera kamptnari ─ ● 23 Pseudoemiliania lacunosa ● ● ● ─ ● ─ ● ─ ─ 24 Reticulofenestra haqii ─ ─ ● ● ● ● o o ● ─ ● 25 Reticulofenestra minuta ● ● ● ● ● ● ─ ● ● 26 Reticulofenestra minutula ─ o ● ● o ● ● ● ● 27 Reticulofenestra pseudoumbilicus ─ ─ ─ ● ● ● ● ● ● ● ● ● o / ─ 28 Sphenolithus abies ● ● ● / / ● / o / / / ● ● ● ─ ● ● 29 Sphenolithus moriformis ─ ● ● ● ● ● o ● ● o o ● ● o ● ● ─ ● 30 Sphenolithus neoabies o ● o o / / / / / / / ● o ─ Notes: Abudance of NannofossilsIJOG species, /: Abudant (>10), o: Commond (6-10), ●: Frequent (2-5), ─ : Occasional (1) Reticulofenestra rotaria, Rhabdosphaera clavig- derived from sample D.25 to D.28 consisting era, Spenolithus moriformis, Spenolithus abies, of ten genera with forteen species; those are: Spenolithus neoabies, Syracosphaera sp., and Calcidiscus leptoporus, Coccolithus pelagicus, Umbilicosphaera jafari. Coccolithus pliopelagicus, Discoaster triradia- The nannofossils recognized in Calcare - tus, Gephyrocapsa carribeanica, Gephyrocapsa ous Sandstone Unit of Sonde Formation are oceanica, Helicosphaera carteri, Helicosphaera

20 Nannofossil Distribution and Age of Kendeng Zone In Kalibeng River Section of Kedungringin, Plandaan Area, Jombang, East Java (S.U. Choiriah et al. )

Calcidiscusleptoporus Calcidiscusleptoporus Coccolithus pelagicus Coccolithus pelagicus Coccolithus pliopelagicus Coccolithus pliopelagicus (// Nicol, 6 µm) (X Nicol, 6 µm) (// Nicol, 13 µm) (X Nicol, 13 µm) (// Nicol, 12 µm) (X Nicol, 12 µm)

Discoasteraltus Discoaster blackstockae Discoaster asymmetricus Discoaster asymmetricus Discoaster berggrenii Discoaster bolli (// Nicol) (// Nicol ) (// Nicol) (// Nicol) (X Nicol) (// Nicol)

Discoaster brouweri Discoaster calcaris Discoaster challengeri Discoasterdruggi Discoasterhamatus Discoaster intercalaris (// Nicol) (// Nicol) (// Nicol) (// Nicol) (// Nicol) (// Nicol)

Discoaster pentaradiatus Discoaster perplexus Discoaster quadramus Discoaster quinqueramus Discoaster triradiatus Discoaster tristellifer (// Nicol) (// Nicol) (// Nicol) (// Nicol) (// Nicol) (// Nicol)

Discoaster variabilis Discoaster surculus Gephyrocapsa caribbeanica Gephyrocapsa oceanica Helicosphaera carteri Helicosphaera carteri (X Nicol) (X Nicol) (X Nicol , 4-5 µm) ( X Nikol, 3.5 to 6) (// Nicol) (X Nicol)

Helicosphaera granulata Ceratolithus acutus Pseudoemiliania lacunosa Pseudoemiliania lacunosae Pseudoemiliania ovata Pseudoemiliania ovata (X Nicol) (X Nicol) (// Nicol, >4µm) (X Nicol, >4µm) ( // Nicol, 3-4µm) ( X Nicol 3-4µm)

Reticulofenestra pseudoumbilica Reticulofenestra minuta Reticulofenestra minuta Reticulofenestra minutula Reticulofenestra pseudoumbilica (X Nicol, and // Nicol,, 6 µm) (// Nicol <3μm) (X Nicol, 3 µm) (X Nicol 3-5 µm) (X Nicol, 7µm)

Reticulofenestra rotaria Rhabdospaera clavigera Scyphosphaera globulata Sphenolithus abies Sphenolithus moriformis Sphenolithus neoabies (X Nicol) IJOG(// Nikol) (?? Nicol) (X Nicol, 3 -4 µm) (X Nicol, 3 -7 µm (X Nicol, 2 -3 µm)

Syracopsphaera sp. Umbilicospaera jafari Helicosphaera selli Reticulofenestra Discoaster brouweri (X Nikol) (X nikol) (// Nicol, X Nicol,12 µm) 1µm dg SEM 2µm dg SEM

Figure 4. Photomicrographs of nannofossil species (1000x) in the researched area.

21 Indonesian Journal on Geoscience, Vol. 7 No. 1 April 2020: 15-24 selli, Pseudoemiliania lacunosa, Pseudoemiliania Calcareous Sandstone Unit, and Calcareous ovata, Reticulofenestra minuta, Rhabdosphaera Claystone Unit of Sonde Formation (Figure 3). clavigera, Syracosphaera sp., and Umbilico- Result of the previous study carried out by sphaera jafari. Choiriah (2001) in Bengawan Solo River of The nannofossils found in Calcareous Clay- Ngawi Section, shows the presence of nineteen stone Unit of Sonde Formation derived from genera and fifty-two species. Kalibeng Formation sample D.29 to D.33 consist of eight genera with contains eighteen genera and forty-nine species, eleven species (Table 1), such as: Calcidiscus while Klitik and Sonde Formations have eight leptoporus, Coccolithus pelagicus, Coccolithus genera and twelve species. Kalibeng Formation is pliopelagicus, Discoaster triradiatus, Gephy- of Late Miocene to Late Pliocene (NN12-NN18) rocapsa carribeanica, Gephyrocapsa oceanica, in age while, Klitik (Sonde) Formation is of Helicosphaera carteri, Helicosphaera kamptnari, Pleistocene (NN19-NN20) (Table 2). Reticulofenestra minuta, Rhabdosphaera clavig- Results of the study from Kalibeng River Sec- era, and Syracosphaera sp. tion of Kedungringin, Plandaan Area, Jombang, The occurrence result of twelve genera and indicate the occurrence of twelve genera and forty-three species indicates that the age of Marl forty-three species. Kalibeng Formation (Marl Unit of Kalibeng is NN10-NN18, Calcareous Unit) containing twelve genera and thirty-nine Sandstone Unit of Sonde is NN19, and Calcare- species, sends to indicate that the age of this ous Claystone Unit of Sonde is NN20-NN21, formation ranges from Middle Miocene to Late according to the classification of Martini (1971). Pliocen (NN10 to NN18). The index fossil used to indicate age in this While Sonde Formation (Calcareous Sand- research is the first and t h e last appearance of stone Unit) is of Pleistocene (NN19) and Cal- species Ceratolithus acutus, Discoaster asym- careous Claystone Unit of Klitik Formation metricus, Pseudoemiliana lacunose, Discoaster is Pleistocene (NN20 to NN21) in age (Table 2 surculus, and Sephyrocopsa oceanica. and Figure 5). The results of the study show the differences in age, especially for the Sonde/Klitik Formation. Discussion Based on the nannofossil analysis, the Klitik/ Sonde Formation is of Pleistocene, which is The studied area belongs to the type locality younger than the age based on the foraminifera of the Kalibeng Formation in Kendeng Zone, with analysis (Pliocene). The correlation of the same the order of stratigraphy from older to younger formation based on foraminifera biostratigraphy consists of Marl Unit of Kalibeng Formation, with nannofossil is shown in Figure 5.

Table 2. Correlation of Nannofossil Distribution and The Age of Unit/Formation

Kalibeng River, Kedungringin Section, Jombang, 12 Genus and 43 species Unit/Formation Genus Species Age Calcareous Claystone Unit Sonde 8 11 NN20-N21 (Pleistocene) Calcareous Sandstone UnitIJOG Sonde 10 14 NN19 (Pleistocene) Marl Unit of Kalibeng 12 39 NN10-NN18 (Late Miocene-Late Pliocene)

Bengawan Solo River, Ngawi Section, 19 Genus and 52 Species Unit/Formation Genus Species Age Limestone Unit of Klitik/Sonde 8 12 NN19-NN20 (Pleistocene) Marl Unit of Kalibeng 18 49 NN12-NN18 (Pliocene)

22 Nannofossil Distribution and Age of Kendeng Zone In Kalibeng River Section of Kedungringin, Plandaan Area, Jombang, East Java (S.U. Choiriah et al. )

BIOSTRATIGRAPHIC Pringgoprawiro, 1983 Choiriah, 2001 Choiriah, 2019 AGE CORRELATION CHART Strat. Kendeng Zone Ngawi Section Jombang Section FORAMINIFERA NANNOFOSSIL Foraminifera Nannofossil Nannofossil N23 NN.21 Sonde NN.20 PLEISTOCENE Klitik Sonde N22 NN.19 Pucangan NN.18 N21 NN.17 LATE NN.16 Sonde Klitik N20 NN.15 Kalibeng Kalibeng NN.14 PLIOCENE EARLY N19 NN.13 Kalibeng

N18 NN.12 N17 NN.11 LATE N16

MIOCENE N15

Notes: Regional stratigraphy of Kendeng Zone (Pringgoprawiro, 1983) is prepared based on foraminifera from several regions, especially the location of the formation type.

Figure 5. Age differences of Kalibeng, Klitik, and Sonde Formations of the Kendeng Zone based on foraminifera (Pring- goprawiro, 1983) and nannofossil (Choiriah, 2001).

Conclusion and Recomendation Ngawi which is NN12 to NN18 (or Late Miocene to Late Pliocene). The analysis results conducted during this Sonde Formation (Calcareous Sandstone Unit study identify the presence of twelve genera and Calcareous Claystone Unit) in Jombang is and forty-three species, showing this section has younger than Klitik/Sonde Formation in Ngawi. abundant nannofossils. The age of Marl Unit of Sonde Formation in Jombang indicates NN19− Kalibeng Formation is NN10-NN18 (Middle NN21 (Pleistocene), while that in Ngawi shows Miocene to Pliocene), Calcareous Sandstone Unit NN19 to NN20 (Pleistocene). of Sonde Formation is NN19-NN20 (Pleisto- cene), while the age of Calcareous Claystone Unit of Klitik Formation is NN20-NN21 (Pleistocene). Acknowledgements The distribution of nannofosil in the Kalibeng River, Jombang, indicates fewer genera and spe- The authors would like to thank Kemenristek cies than that of Bengawan Solo River, Ngawi. Dikti for the PUPT research foundation; Dr. Ir. Kalibeng River, Jombang, has twelve genera and Sutarto, M.T. and Purwanto, S.H. for facilitating forty-three species,IJOG while the Bengawan Solo the nannofossil analysis in Petrographic Labora- River, Ngawi Section, has nineteen genera and tory; Ir. Bambang Triwibowo, M.T. for helping to fifty-two species. review the paper; Debby Yulfira, S.T. for helping The correlation results show that the age the fossil analysis, and the chair of Geological of Kalibeng Formation in Jombang is older, Engineering Department, Faculty of Mineral indicating NN10−NN18 (Middle Miocene to Late Technology, UPN “Veteran” Yogyakarta, for the Pliocene) compared to the Kalibeng Formation in support to authors research. The authors’ would

23 Indonesian Journal on Geoscience, Vol. 7 No. 1 April 2020: 15-24 also like to thank all reviewers for their useful Martini, E., 1971. Standard Tertiary and Quater- suggestions to authors’ work. nary calcareous Nannoplankton biozonation. In: Bilal, U.H., 1984 (ed.), Nannofossils Bio- stratigraphy Part III:12., Cenozoic Biostratig- References raphy, Hutchinson Ross Publishing Company, Stroudsburg, Pensylvanian. p.264-307. Aubry, M-P., 1985. Northwestern European Pa- Okada, H. and Bukry, D., 1980. Supplementary leogene magnetostratigraphy, biostratigraphy Modification and Introuction of Code Number and paleogeography: calcareous nannofosil to the Low-Latitude Coccolith Biostrati- evidence. Geology, 13 (3), p.198-202. graphic Zonation (Bukry, 1973; 1975). Berghuis, H.W.K., Troelstra, S.R., and Zaim, Y., Marine Micropaleontology, 5 (3), p.321-325. 2019. Biostratigraphy of the Eastern Kendeng­ DOI:10.1016/0377-8398(80)90016-x Zone (Java, Indonesia): The Marmoyo and Perch-Nielsen, K. and Nielsen., 1985. Ceno- Sumberingin Sections. Journal of Palaeogeog- zoic calcareous nannoplankton, Chapter 10. raphy, Palaeoclimatology, Palaeoecology, 528, In: Bolli, H.M., Saunders, J.B., and Perch- p. 218-231. DOI: 10.1016/j.palaeo.2019.05.008 Nielsen, K. (eds.), Plankton Stratigraphy, Choiriah, S.U., Kapid, R., and Rahardjo, W., Cambridge Earth Science Series, Cam- 2001. The Pliocene/Pleistocene Boundary, bridge Univ. Press, Cambridge, p.427-554. Based On Calcareous Nannofossils, And DOI:10.1017/s0016756800035214 Related Palaeoclimatic Implications, Solo Pringgoprawiro, H., 1983. Biostratigrafi dan River Section, Ngawi Region, East Java, In- palaeogeografi Cekungan Jawa Timur Utara donesia. Journal of Nannoplankton Research pendekatan baru, Disertasi Doktor Teknik London,.23,1, p.15-19. URL: ina.tmsoc.org/ Geologi, ITB, 239pp. JNR/online/23/Choiriah%2 20et%20al%20 Van Gorsel, J.T., Lunt, P., and Morley, R., 2014. 2001%20JNR%20231.pdf. Introduction to Cenozoic biostratigraphy Lunt, P., 2019. The origin of the East of Indonesia, SE Asia, Biostratigraphy of basins deduced from sequence stratigraphy. Southeast Asia Part 1. Indonesian Journal of Journal of Marine and Petroleum Geol- Sedimentary Geology, 29 (4) p.6-40. ogy, 105, p. 17-31. DOI: 10.1016/j.marpet- geo.2019.03.0 38. IJOG

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