Aspek Geokimia Organik Fraksi Hidrokarbon Alifatik Batubara GG-01 Formasi Walat Cekungan Bogor Sukabumi-Jawa Barat

Putri, Dhia Roihanah Erba (2025) Aspek Geokimia Organik Fraksi Hidrokarbon Alifatik Batubara GG-01 Formasi Walat Cekungan Bogor Sukabumi-Jawa Barat. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Analisis biomarka fraksi hidrokarbon alifatik sampel Batubara GG-01 Formasi Walat, Cekungan Bogor, Sukabumi, Jawa Barat dilakukan dengan metode ekstraksi, fraksinasi, dan identifikasi dengan kromatografi gas–spektrometri massa (KG-SM) untuk mengetahui karakteristik geokimia organik. Keberadaan biomarka teridentifikasi mencakup n-alkana, isoprenoid, seskuiterpenoid, dan triterpenoid pentasiklik. Sumber bahan organik didominasi oleh tumbuhan tingkat tinggi terestrial, yang ditunjukkan oleh dominasi n-alkana rantai panjang (n-C27 dan n-C29), nilai CPI sebesar 1,30 (>1), nilai OEP-2>OEP-1, nilai TMD sebesar 1,95 (>1), nilai TAR sebesar 2,99 (>1), nilai WI sebesar 4,40 (>1), nilai LHCPI sebesar 0,32 (<1), rasio LMW/HMW sebesar 0,23 (<1), n-C31/n-C19 sebesar 1,69 (>0,4), n-C17/n-C31 sebesar 0,51 (<2), 8β(H)-homodrimana/8β(H)-drimana sebesar 1,76 (>1). Sedikit masukan dari tumbuhan akuatik ditunjukkan oleh nilai Paq sebesar 0,46 (>0,4) dan sedikit masukan dari bakteri ditunjukkan oleh keberadaan senyawa hopanoid. Kematangan termal ditunjukkan melalui nilai CPI dan OEP ≈ 1, rasio C30Moretana/C30Hopana sebesar 0,33 dan rasio C31 – C32 (22S/(22S+22R)) sebesar 0,58 dan 0,62 mengindikasikan batubara sudah memasuki tahap kematangan awal hingga menengah. Lingkungan pengendapan oksik ditunjukkan oleh rasio Pr/Ph sebesar 8,20 (>3), disertai dengan penurunan kelimpahan C31 – C32 αβ 22S dan 22R homohopana, serta hasil plot pada Diagram Hunt antara Pr/n-C17 dan Ph/n-C18. Klasifikasi Batubara GG-01 termasuk ke dalam kerogen tipe III yang berpotensi sebagai gas prone.
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The biomarker analysis of aliphatic hydrocarbon fraction from the GG-01 coal sample of the Walat Formation, Bogor Basin, Sukabumi, West Java, was conducted through extraction, fractionation, and identification using gas chromatography–mass spectrometry (GC-MS) to determine its organic geochemical characteristics. The identified biomarkers include n-alkanes, isoprenoids, sesquiterpenoids, and pentacyclic triterpenoids. The organic matter is predominantly derived from terrestrial higher plants, as indicated by the dominance of long-chain n-alkanes (n-C27 and n-C29), CPI value of 1,30 (>1), OEP-2 > OEP-1, TMD value of 1,95 (>1), TAR value of 2,99 (>1), WI value of 4,40 (>1), LHCPI of 0,32 (<1), LMW/HMW ratio of 0,23 (<1), n-C31/n-C19 ratio of 1,69 (>0,4), n-C17/n-C31 ratio of 0,51 (<2), and 8β(H)-homodrimane/8β(H)-drimane ratio of 1,76 (>1). A minor contribution from aquatic plants is suggested by a Paq value of 0,46 (>0,4), while bacterial input is indicated by the presence of hopanoids. Thermal maturity is inferred from CPI and OEP values close to 1, a C30Moretane/C30Hopane ratio of 0,33 and C31–C32 hopane 22S/(22S+22R) ratios of 0,58 and 0,62 indicating an early to mid-mature stage. An oxic depositional environment is inferred from a pristane/phytane (Pr/Ph) ratio of 8,20 (>3), decreasing abundance of C31–C32 αβ 22S and 22R homohopanes, and the Hunt diagram plot between Pr/n-C17 and Ph/n-C18. The GG-01 coal is classified as type III kerogen, suggesting potential as a gas-prone source rock.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Batubara GG-01, Biomarka, Formasi Walat, Geokimia Organik, Hidrokarbon Alifatik, GG-01 Coal, Biomarkers, Walat Formation, Organic Geochemistry, Aliphatic Hydrocarbon
Subjects:	Q Science > QD Chemistry
Divisions:	Faculty of Science and Data Analytics (SCIENTICS) > Chemistry > 47201-(S1) Undergraduate Thesis
Depositing User:	Dhia Roihanah Erba Putri
Date Deposited:	05 Aug 2025 12:15
Last Modified:	05 Aug 2025 12:15
URI:	http://repository.its.ac.id/id/eprint/127582

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