TIPE INTERVAL T2- HUMMOCKY PADA ENDAPAN BADAI (TEMPESTIT), FORMASI NANGGULAN, PEGUNUNGAN KULON PROGO, YOGYAKARTA

Penulis

  • siti Nuraini ITNY
  • Ildrem Syafri Padjadjaran University
  • Budi Muljana Padjadjaran University
  • Adjat Sudradjat Padjadjaran University

DOI:

https://doi.org/10.33579/krvtk.v10i2.5800

Kata Kunci:

Hummocky, tempestite, storm, current

Abstrak

Komposisi lapisan endapan badai (tempestit) dinyatakan sebagai suatu endapan pengangsuran normal atau endapan menghalus ke atas, terbagi ke dalam 3 unit yaitu bagian bawah, bagian tengah dan bagian atas. Bagian bawah mencirikan klastika kasar, bagian tengah dikenal sebagai T2 tersusun dari gabungan lapisan hummocky dan swalley mengandung klastika lebih halus dengan pemilahan yang baik. Bagian atas menunjukan pengendapan perlapisan dalam kondisi arus semakin tenang berklastika halus: lempung. Interval T2 sering dianggap sebagai penciri model endapan turbidit akibat aliran grafitasi. Padahal di sisi lain, sifat arus akibat badai (hummocky-swalley) lebih bervariasi dikarenakan peran 3 arus yang mengontrolnya yaitu arus oskilasi, arus dasar (bottom curren) dan arus kombinasi. Penelitian ini akan mengupas karakter interval T2 badai (tempestit) pada Formasi Nanggulan. Metode yang diterapkan yaitu pembuatan penampang stratigrafi pada 3 lintasan (Kali Clumprit, Watupuru dan Songgo), korelasi umur ketiga penampang stratigrafi dan analisis arus purba. Endapan badai dijumpai dalam Formasi Nanggulan yang berumur Eosen Tengah, menunjukan arah arus polimodal yang bersifat bertolak belakang dan bercabang di interval T2nya. Pola tersebut mencerminkan dua arah saling berlawanan yaitu arus dasar (bottom current) dan arus oskilasi badai. Di sisi lain pola arus kombinasi terbentuk yang cenderung bercabang dari pola arus utamanya. Lapisan T2 Watupuru berkomposisi lapisan hummocky yang saling bertumpukan, maju ke arah baratlaut. Arah baratlaut ini diinterpretasikan sebagai pantai purba atau wilayah daratan.

Unduhan

Data unduhan belum tersedia.

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2025-11-28

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[1]
siti Nuraini, I. Syafri, B. Muljana, dan A. Sudradjat, “TIPE INTERVAL T2- HUMMOCKY PADA ENDAPAN BADAI (TEMPESTIT), FORMASI NANGGULAN, PEGUNUNGAN KULON PROGO, YOGYAKARTA”, Journal Technology of Civil, Electrical, Mechanical, Geology, Mining, and Urban Design, vol. 10, no. 2, Nov 2025.

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Vol 10 No 2 (2025): Energy Management and Sustainable Environment

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