eprintid: 1080 rev_number: 8 eprint_status: archive userid: 15 dir: disk0/00/00/10/80 datestamp: 2020-07-20 08:19:23 lastmod: 2020-07-20 08:19:23 status_changed: 2020-07-20 08:19:23 type: conference_item metadata_visibility: show creators_name: Herning Dyah Kusuma Wijayanti, . creators_name: Okki Verdiansyah, . creators_name: Moch. Indra Novian, . creators_name: Nugroho Iman Setiawan, . creators_name: Kholilur Rohman, . title: Protolith of Joko Tuo Marble, Bayat, Central Java; contribution to paleoenvironment and age of metamorphic rock. ispublished: pub subjects: QE abstract: Abstract Marble and Phyllite are well known as Pre-Tertiary basement rock crop out in Joko Tuo area, East Jiwo Hill, Central Java. These rocks contain fossil record even though they have undergone metamorphism. Preliminary petrographic study in several samples of show the existence of larger foraminifera Orbitolina sp. in good preservation condition between foliated of chlorite-biotit-graphite. Based on petrographic data, the metamorphic rocks that were studied comprised of foliated marble that dominantly consist of calcite, chlorite, biotit, graphite and feldspar. The protolith of metamorphic rock interpreted derived from fine grained calcareous sedimentary rock which was deposited in shalow marine environment at Late Cretaceous age. Introduction The protolith of a metamorphic rock is defined as the original rock prior to metamorphism. This is comprises rocks of all possible chemical compositions and include the entire range of sedimentary, igneous and metamorphic rocks. The protolith of a metamorphic rock can be interpreted based on the mineralogy and/or the rock texture. The marble and phyllite in Joko Tuo area, East Jiwo Hills is interesting object for protolith study. Preliminary investigation show that these rocks contain fossil record even though they have undergone metamorphism. The preservation of fossils in metamorphic rocks is unusual, except in low-grade metamorphosed sedimentary rocks. This paper explains petrographical observation of some sample from Joko Tuo area. The study of protolith and surviving fossil content in this area will contribute the paleoenvironment and age of the Jiwo Hills terrane. Geological Outline Geologically, Jiwo Hills, Bayat, Central Java (Figure 1) built by elevated basement rocks covered by a relatively thin marine sedimentary rock layers and intruded by numerous igneous rock bodies (Salahuddin & Novian, 2014). The basement complex mostly composed of metamorphic rocks, such as phyllites, mica schists, calc-silicate schist and marbles (Setiawan et al., 2013). Amphibolite, blue schist, and sepentinite also reported present in this area (Warmada et al., 2008). Among them, phyllites are the most widespread, generally in weathered condition with some quartz veins and calcite veins aligned with their foliation. In Pre-Tertiary Jiwo, no fossiliferous beds have been found, only boulders of Orbitolina limestone derived from neogene conglomerate have been found near desa Santren which shows that at least part of pre Tertiary sub stratum is Cretaceous age (Bothé, 1929). The age of this basement rocks by applying K-Ar absolute dating indicate an age of 98 mya or Late Cretaceous (Prasetyadi, 2007). This metamorphic rocks is interpreted to be formed during a regional metamorphism that involved along an ancient subducting lithospheric plate and the plates collision afterward (Setiawan et al., 2014). Figure 1: Geological Map of Jiwo Hills (after Rahardjo, 1994). The red box is the location of Joko Tuo area. Corresponding author : Herning Dyah Kusuma Wijayanti herningdkusuma@gmail.com date: 2016-10-10 date_type: published official_url: https://itny.ac.id contact_email: library@sttnas.ac.id full_text_status: public pres_type: paper pagerange: 1-4 event_title: GEOSEA XIV AND 45TH IAGI ANNUAL CONVENTION 2016 (GIC2016) event_location: The Trans Luxury Hotel, Bandung event_dates: 10-13 Oktober 2016 event_type: conference refereed: TRUE referencetext: References Alfyan, M.F., Setiawan, N.I., 2014. Petrogenesis Batuan Metamorf di Daerah Perbukitan Jiwo, Kecamatan Bayat, Kabupaten Klaten, Provinsi Jawa Tengah. Seminar Nasional Kebumian 7, Geological Engineering Department, Faculty of Engineering, Universitas Gadjah Mada, Yogyakarta. Best, M.G., 2003. Igneoous and Metamorphic Petrology. Blackwell Publishing Company, Victoria-Berlin, 2nd ed. Boudhager-Fadel, M.K., 2008, Evolution And Geological Significance of Larger Benthic Foraminifera, Elsevier, Amsterdam. Bothé, A.Ch.D (1929) Jiwo Hills and Southern Range Excursion Guide. IVth Pacific Science Congress, Java, Bandung, pp. 1-14. Flugel, E., 2004, Microfacies of Carbonate Rocks: Analysis, Interpretation and Application, Springer, Berlin. Husein, S., and Novian, M.I., 2014, Guide book: Geology Excursion to Bayat, Central Java – Santos (Sampang) Pty.Ltd., Geological Engineering UGM, pp. 1-14. Prasetyadi, C., 2007, Evolusi Tektonik Paleogen Jawa Bagian Timur. Disertasi, Program Doktor Teknik Geologi, Institut Teknologi Bandung. Setiawan, N.I., Yasuhito, O., Prasetyadi, C., 2013, A Preliminary View and Importance of Metamorphic Geology from Jiwo Hills in Central Java, Prosiding Seminar Nasional Kebumian ke-6, Yogyakarta pp.11-21. Setiawan, N.I., S. Husein, and M.F. Alfyan (2014) Speculative models of exhumation on high-pressure low-temperature metamorphic rocks from central part of Indonesia: an implementation of concepts and processes. Prosiding Seminar Nasional Kebumian ke-7, Yogyakarta. Warmada, I.W., Sudarno, I., and Wijanarko, D., 2008, Geologi dan Facies Batuan Metamorf daerah Jiwo Barat, Bayat, Klaten, Jawa Tengah, Media Teknik, vol.2, pp.113-118. Bothé, A.Ch.D (1929) Jiwo Hills and Southern Range Excursion Guide. IVth Pacific Science Congress, Java, Bandung, pp. 1-14. Preservation of fossils are common in foliated marble sample with diferent style of deformation. Some fosills are trasformed from micrite-calcite into brucite-chlorite The fossils recognize as Orbitolina sp., a large agglutinated foraminifera. They comprise important biostratigraphic markers and are used for biozonations, particularly for for Barremian, Aptian, Albian and Cenomanian (Late Lower – Early Upper Cretaceous) platforms and ramps (Flugel, 2004; Marcelle and Boudhager-Fadel, 2008). This new finding confirm that the age of part of metamorphic rocks in Jiwo Hills is Cretaceous. Unraveling detailed paleoenvironmental conditions in which low grade metamorphisme and metasediments formed is often a challenge. The dominance of fine-grained carbonate together with carbon and Orbitolina sp. points to deposition was in shallow marine setting close to transitional environment. The presence of feldspar indicate that the sediment material derived from volcanic source and becomes interesting when linked to the fact that the oldest recorded volcanism in Java is in Paleogene. This data guide to the new hypothesis of the existance of Cretaceous volcanism. Furthermore, intergrated study in Jiwo Hill area is needed to understanding the evolution of paleogeography and tectonic evolution in this area. Conclusion The metamorphic rocks in Joko Tuo area are very low grade metamorphism; foliated marble and marble. The protolith of metamorphic rock interpreted derived from fine grained calcareous sedimentary rock associate with carbon and pelitic sediment. The presence of feldspar is indicate the existence of Cretaceous volcanism. Marine fossil assemblages preserve in metamorphic rocks recognize as Orbitolina sp. which is indicate Late Lower – Early Upper Cretaceous age. Based on the textural, mineral composition and fossil content the paleoenvironment of this rocks are interpretated in shalow marine environment. References Alfyan, M.F., Setiawan, N.I., 2014. Petrogenesis Batuan Metamorf di Daerah Perbukitan Jiwo, Kecamatan Bayat, Kabupaten Klaten, Provinsi Jawa Tengah. Seminar Nasional Kebumian 7, Geological Engineering Department, Faculty of Engineering, Universitas Gadjah Mada, Yogyakarta. Best, M.G., 2003. Igneoous and Metamorphic Petrology. Blackwell Publishing Company, Victoria-Berlin, 2nd ed. Boudhager-Fadel, M.K., 2008, Evolution And Geological Significance of Larger Benthic Foraminifera, Elsevier, Amsterdam. Bothé, A.Ch.D (1929) Jiwo Hills and Southern Range Excursion Guide. IVth Pacific Science Congress, Java, Bandung, pp. 1-14. Flugel, E., 2004, Microfacies of Carbonate Rocks: Analysis, Interpretation and Application, Springer, Berlin. Husein, S., and Novian, M.I., 2014, Guide book: Geology Excursion to Bayat, Central Java – Santos (Sampang) Pty.Ltd., Geological Engineering UGM, pp. 1-14. Prasetyadi, C., 2007, Evolusi Tektonik Paleogen Jawa Bagian Timur. Disertasi, Program Doktor Teknik Geologi, Institut Teknologi Bandung. Setiawan, N.I., Yasuhito, O., Prasetyadi, C., 2013, A Preliminary View and Importance of Metamorphic Geology from Jiwo Hills in Central Java, Prosiding Seminar Nasional Kebumian ke-6, Yogyakarta pp.11-21. Setiawan, N.I., S. Husein, and M.F. Alfyan (2014) Speculative models of exhumation on high-pressure low-temperature metamorphic rocks from central part of Indonesia: an implementation of concepts and processes. Prosiding Seminar Nasional Kebumian ke-7, Yogyakarta. Warmada, I.W., Sudarno, I., and Wijanarko, D., 2008, Geologi dan Facies Batuan Metamorf daerah Jiwo Barat, Bayat, Klaten, Jawa Tengah, Media Teknik, vol.2, pp.113-118. Bothé, A.Ch.D (1929) Jiwo Hills and Southern Range Excursion Guide. IVth Pacific Science Congress, Java, Bandung, pp. 1-14. Preservation of fossils are common in foliated marble sample with diferent style of deformation. Some fosills are trasformed from micrite-calcite into brucite-chlorite The fossils recognize as Orbitolina sp., a large agglutinated foraminifera. They comprise important biostratigraphic markers and are used for biozonations, particularly for for Barremian, Aptian, Albian and Cenomanian (Late Lower – Early Upper Cretaceous) platforms and ramps (Flugel, 2004; Marcelle and Boudhager-Fadel, 2008). This new finding confirm that the age of part of metamorphic rocks in Jiwo Hills is Cretaceous. Unraveling detailed paleoenvironmental conditions in which low grade metamorphisme and metasediments formed is often a challenge. The dominance of fine-grained carbonate together with carbon and Orbitolina sp. points to deposition was in shallow marine setting close to transitional environment. The presence of feldspar indicate that the sediment material derived from volcanic source and becomes interesting when linked to the fact that the oldest recorded volcanism in Java is in Paleogene. This data guide to the new hypothesis of the existance of Cretaceous volcanism. Furthermore, intergrated study in Jiwo Hill area is needed to understanding the evolution of paleogeography and tectonic evolution in this area. Conclusion The metamorphic rocks in Joko Tuo area are very low grade metamorphism; foliated marble and marble. The protolith of metamorphic rock interpreted derived from fine grained calcareous sedimentary rock associate with carbon and pelitic sediment. The presence of feldspar is indicate the existence of Cretaceous volcanism. Marine fossil assemblages preserve in metamorphic rocks recognize as Orbitolina sp. which is indicate Late Lower – Early Upper Cretaceous age. Based on the textural, mineral composition and fossil content the paleoenvironment of this rocks are interpretated in shalow marine environment. References Alfyan, M.F., Setiawan, N.I., 2014. Petrogenesis Batuan Metamorf di Daerah Perbukitan Jiwo, Kecamatan Bayat, Kabupaten Klaten, Provinsi Jawa Tengah. Seminar Nasional Kebumian 7, Geological Engineering Department, Faculty of Engineering, Universitas Gadjah Mada, Yogyakarta. Best, M.G., 2003. Igneoous and Metamorphic Petrology. Blackwell Publishing Company, Victoria-Berlin, 2nd ed. Boudhager-Fadel, M.K., 2008, Evolution And Geological Significance of Larger Benthic Foraminifera, Elsevier, Amsterdam. Bothé, A.Ch.D (1929) Jiwo Hills and Southern Range Excursion Guide. IVth Pacific Science Congress, Java, Bandung, pp. 1-14. Flugel, E., 2004, Microfacies of Carbonate Rocks: Analysis, Interpretation and Application, Springer, Berlin. Husein, S., and Novian, M.I., 2014, Guide book: Geology Excursion to Bayat, Central Java – Santos (Sampang) Pty.Ltd., Geological Engineering UGM, pp. 1-14. Prasetyadi, C., 2007, Evolusi Tektonik Paleogen Jawa Bagian Timur. Disertasi, Program Doktor Teknik Geologi, Institut Teknologi Bandung. Setiawan, N.I., Yasuhito, O., Prasetyadi, C., 2013, A Preliminary View and Importance of Metamorphic Geology from Jiwo Hills in Central Java, Prosiding Seminar Nasional Kebumian ke-6, Yogyakarta pp.11-21. Setiawan, N.I., S. Husein, and M.F. Alfyan (2014) Speculative models of exhumation on high-pressure low-temperature metamorphic rocks from central part of Indonesia: an implementation of concepts and processes. Prosiding Seminar Nasional Kebumian ke-7, Yogyakarta. Warmada, I.W., Sudarno, I., and Wijanarko, D., 2008, Geologi dan Facies Batuan Metamorf daerah Jiwo Barat, Bayat, Klaten, Jawa Tengah, Media Teknik, vol.2, pp.113-118. Bothé, A.Ch.D (1929) Jiwo Hills and Southern Range Excursion Guide. IVth Pacific Science Congress, Java, Bandung, pp. 1-14. citation: Herning Dyah Kusuma Wijayanti, . and Okki Verdiansyah, . and Moch. Indra Novian, . and Nugroho Iman Setiawan, . and Kholilur Rohman, . (2016) Protolith of Joko Tuo Marble, Bayat, Central Java; contribution to paleoenvironment and age of metamorphic rock. In: GEOSEA XIV AND 45TH IAGI ANNUAL CONVENTION 2016 (GIC2016), 10-13 Oktober 2016, The Trans Luxury Hotel, Bandung. document_url: https://repository.itny.ac.id/id/eprint/1080/1/IAGI%202016%20HERNING%20DYAH.pdf