DAFTAR ISI HALAMAN PENGESAHAN ................................................................................................ i PERNYATAAN ...................................................................................................................... ii PRAKATA .............................................................................................................................. iii DAFTAR ISI ........................................................................................................................... v DAFTAR GAMBAR .............................................................................................................. vii DAFTAR TABEL ................................................................................................................... ix DAFTAR LAMPIRAN .......................................................................................................... x SARI......................................................................................................................................... xi ABSTRACT .............................................................................................................................. xii BAB I PENDAHULUAN ....................................................................................................... 1 I.1. Latar Belakang ....................................................................................................... 1 I.2. Maksud Dan Tujuan Penelitian .............................................................................. 4 I.3. Manfaat Penelitian.................................................................................................. 4 I.4. Lokasi Penelitian .................................................................................................... 4 I.5. Penelitian Terdahulu .............................................................................................. 6 BAB II GEOLOGI REGIONAL ........................................................................................... 8 II.1. Fisiografi Regional ............................................................................................... 8 II.2. Stratigrafi Regional ............................................................................................... 14 II.3. Struktur Geologi Regional .................................................................................... 21 BAB III LANDASAN TEORI ............................................................................................... 25 III.1. Pengertian Fasies ................................................................................................. 25 III.2. Litofasies ............................................................................................................. 26 III.3. Hubungan Rheologi Batuan Dan Deformasi Batuan Pada Formasi Halang ....... 28 III.4. Struktur Geologi .................................................................................................. 29 III.5. Konsep Drag Fold ............................................................................................... 34 III.6. Konsep Harding (1973) ....................................................................................... 37 III.7. Hipotesis .............................................................................................................. 41 BAB IV METODOLOGI PENELITIAN ............................................................................. 42 IV.1. Alat Dan Bahan ................................................................................................... 42 IV.2. Tahap Penelitian .................................................................................................. 44 v
IV.3. Tahap Analisa Laboratorium dan Pengolahan Data ............................................ 48 IV.4. Tahap Penyusunan Laporan ................................................................................ 49 IV.5. Waktu Penelitian ................................................................................................. 51 BAB V PEMBAHASAN......................................................................................................... 52 V.1. Analisis Petrologi/Petrografi Dan Stratigrafi........................................................ 52 V.2. Pengukuran Data Struktur Dan Observasi ............................................................ 63 V.2. Analisis Stress....................................................................................................... 65 V.3. Analisis Strain ...................................................................................................... 67 V.4. Analisis Struktur Dan Konsep Harding Dalam Pembentukan Struktur Geologi daerah penelitian.................................................................................... 69 V.5. Mekanisme Deformasi .......................................................................................... 71 V.6. Pemodelan Perkembangan Deformasi Struktur Daerah Penelitian ...................... 73 V.8. Sejarah Geologi .................................................................................................... 76 BAB VI KESIMPULAN ........................................................................................................ 79 DAFTAR PUSTAKA ............................................................................................................. 81
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DAFTAR GAMBAR Gambar I.1. Peta indeks dan lokasi penelitian ..................................................................... 5 Gambar II.1. Letak pegunungan Serayu Selatan pada fisiografi Jawa Tengah setelah Van Bemmelen (1970), telah dimodifikasikan ................................ 9 Gambar II.2. Sesar Geser Dekstral Pamanukan-Cilacap dan Sesar Geser Sinistral Kebumen-Muria sebagai pengontrol utama fisiografi Pegunungan Serayu Selatan (Satyana, 2009).................................................................... 11 Gambar II.3. Fiosigrafi tektonik Jawa Tengah bagian selatan (Sujanto dan Roskamil, 1975), digambarkan kembali ...................................................... 12 Gambar II.4. Kolom stratigrafi daerah Kebumen (Asikin, 1992), telah dimodifikasi ......... 17 Gambar II.5. Peta pola struktur geologi Pulau Jawa (Pulunggono dan Martodjojo, 1994), telah dimodifikasi ............................................................................. 22 Gambar III.1. Grafik hubungan stress dan strain, (Billings, 1982) ..................................... 29 Gambar III.2. Susunan perlapisan batuan sedimen pada awal pengendapan (Owen dkk, 2006) dieditkan kembali ....................................................................... 30 Gambar III.3. Sketsa sistem sesar (sumber: http://www.smkn5baru.sch.id) ....................... 31 Gambar III.4. Sketsa dari beberapa sistem sesar tunggal (Owen dkk, 2006) dieditkan kembali ......................................................................................... 33 Gambar III.5. Sketsa pergerakan drag fold dan berbagai bentuknya (Davis dan Reynolds, 1984), dieditkan kembali ............................................................. 36 Gambar III.6. Perbandingan antara “Pure Shear” (perbedaan pergerakan horizontal) dan “Simple Shear” (kompresi yang miring) Thomas et al., (1973) ..................................................................................................... 39 Gambar III.7. Modelan “Simple Shear” menurut Harding (1973) ...................................... 40 Gambar III.8. Hubungan tegasan dan shear, Harding (1973).............................................. 40 Gambar IV.1. Bagan alir Metodologi Penelitian 50 Gambar V.1. Korelasi key bed 1 dan key bed 2 dari singkapan sayang bagian utara dan selatan (Kamera menghadap ke timur) .................................................. 53 Gambar V.2. Sampel batupasir masif dari key bed 1............................................................ 56 Gambar V.3. Sampel batupasir silang – siur dari key bed 2 ................................................. 57 Gambar V.4. Beberapa struktur sedimen yang dijumpai pada singkapan di daerah penelitian ...................................................................................................... 57 Gambar V.5. Sampel batunapal dari singkapan daerah penelitian ....................................... 58 Gambar V.6. Fosil – fosil penciri umur dan lingkungan pengendapan dari daerah penelitian ...................................................................................................... 60 Gambar V.7. Hasil korelasi MS sayap bagian utara, sayap bagian tengah atau bagian sesar dan sayap bagian selatan dari daerah penelitian ...................... 62
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Gambar V.8. Kenampakan sesar turun menggeser sinistral serta sesar antitetiknya dan sesar naik di darah penelitian bukit Cadas / Bajangan (Kamera menghadap ke timurlaut) .............................................................................. 64 Gambar V.9. Hasil pemprosesan data struktur bidang sesar dengan menggunakan software ........................................................................................................ 66 Gambar V.10. Analisis pergerakan sebenarnya dari struktur sesar Kedungramat terhadap sesar geser sinistral daerah penelitian ........................................... 68 Gambar V.11. Kenampakan gores – garis dan cermin sesar dari sesar turun menggeser sinistral (Kamera menghadap ke utara) ..................................... 70 Gambar V.12. Kenampakan dari drag fold dan fault breccia dari bagian sesar utama yaitu sesar turun menggeser sinistral, sayap bagian selatan (Kamera menghadap timur) ......................................................................... 72 Gambar V.13. Skema pemodelan dari perkembangan struktur sesar turun menggeser sinistral dan sesar naik di Bukit Cadas 75 Gambar V.14. Struktur sedimen slump pada sayap bagian utara (kanan) dan sayap bagian selatan (kiri) ...................................................................................... 77
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DAFTAR TABEL Tabel IV.1. Waktu penelitian tahun 2015 – 2016.................................................................... 51 Tabel V.1. Hasil pengukuran bidang sesar di lokasi penelitian ............................................... 65
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DAFTAR LAMPIRAN Lampiran Terikat: LAMPIRAN 1 : CHART FOSIL .................................................................................... 1-6 LAMPIRAN 2 : FOTO FOSIL ........................................................................................7-17 LAMPIRAN 3 : PETROGRAFI ......................................................................................18-40 Lampiran Lepas: LAMPIRAN 4 : PERKEMBANGAN STRIKE DIP SELURUH PERLAPISAN .......41-43 LAMPIRAN 5 : MS (MEASUREMENT STRATIGRAPHY) .........................................44-47
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