• Arifudin Idrus Department of Geological Engineering Universitas Gadjah Mada
  • Fadlin Fadlin Study Program of Geological Engineering, Universitas Jenderal Soedirman



BLEG, exploration, geochemical anomaly, Halmahera


Halmahera Island retains several gold deposits. One of the gold deposits is called as low sulphidation epithermal (LSE) quartz veins which is currently being mined and is situated in the Gosowong goldfield. The veins mostly originated in N-S and NNE-SSW direction. This study is aimed to determine the prospect area in the northern portion of Gosowong goldfield covering the West Kao sub district based on surface mapping and rock/float- and BLEG stream sediment survey. A total of 16 rock/vein float and 120 BLEG samples were analyzed by FA/AAS and CNO2 cyanide leach methods, respectively. The study area is occupied by tuffaceous sandstone, andesite, porphyritic andesite and lava andesite units. In the eastern part, tuffaceous sandstone is suffered from argillic and propylitic alteration, which may be controlled by the NW-SE-trending structures. The gold grade of rock/float samples is up to 0.044 ppm. BLEG data indicates a calculated threshold of 10 ppb for Au and 72 ppb for Ag. The highest Au and Ag contents (anomalies) are identified in the eastern part of the study area. This is spatially (and maybe genetically) related to the argillic-altered tuffaceous sandstone, structures and occurrences of quartz vein floats. To follow up this finding, a detailed exploration is recommended to be conducted within the prospect area.


Arne, D. and MacFarlane, B. (2014) ‘Reproducibility of gold analyses in stream sediment samples from the White Gold District and Dawson Range, Yukon Territory, Canada’, Explore, (164), pp. 1–10.

Böhmer, M. and Kucera, M. (1986) Prospecting and exploration of mineral deposits, Volume 21. 2nd edn. Amsterdam: Elsivier.

Buchanan, L. J. (1981) ‘recious metal deposits associated with volcanic environments in the Southwest’, in Dickinson, W. R. and Payne, W. D. (eds) Relations of tectonics to ore deposits in the southern Cordillera. Arizona Geological Society Digest, pp. 237–262.

Carlile, J. C., Davey, G. R., Kadir, I., Langmead, R. P. and Rafferty, W. J. (1998) ‘Discovery and exploration of the Gosowong epithermal gold deposit, Halmahera, Indonesia’, Journal of Geochemical Exploration, 60(3), pp. 207–227. doi: 10.1016/S0375-6742(97)00048-4.

Carlile, J. C. and Mitchell, A. H. G. (1994) ‘Magmatic arcs and associated gold and copper mineralization in Indonesia’, Journal of Geochemical Exploration, 50(1–3), pp. 91–142. doi: 10.1016/0375-6742(94)90022-1.

Carranza, E. J. M. (2004) ‘Usefulness of stream order to detect stream sediment geochemical anomalies’, Geochemistry: Exploration, Environment, Analysis, 4(4), pp. 341–352. doi: 10.1144/1467-7873/03-040.

Chen, X., Zheng, Y., Xu, R., Wang, H., Jiang, X., Yan, H., Cai, P. and Guo, X. (2016) ‘Application of classical statistics and multifractals to delineate Au mineralization-related geochemical anomalies from stream sediment data: a case study in Xinghai-Zeku, Qinghai, China’, Geochemistry: Exploration, Environment, Analysis, 16(3–4), pp. 253–264. doi: 10.1144/geochem2016-424.

Cohen, D. R., Dunlop, A. C. and Rose, T. (2005) ‘Contrasting dispersion patterns for gold in stream sediments at Timbarra, NSW, Australia’, Journal of Geochemical Exploration, 85(1), pp. 1–16. doi: 10.1016/j.gexplo.2004.08.002.

Garwin, S., Hall, R. and Watanabe, Y. (2005) ‘Tectonic setting, geology, and gold and copper mineralization in Cenozoic Magmatic Arcs of Southeast Asia and the West Pacific’, in Hedenquist, J. W. et al. (eds) One Hundredth Anniversary Volume. Society of Economic Geologists, pp. 891–930. doi: 10.5382/AV100.27.

Gemmell, J. B. (2007) ‘Hydrothermal alteration associated with the Gosowong epithermal Au-Ag deposit, Halmahera, Indonesia: Mineralogy, geochemistry, and exploration implications’, Economic Geology, 102(5), pp. 893–922. doi: 10.2113/gsecongeo.102.5.893.

Grunsky, E. C. (2010) ‘The interpretation of geochemical survey data’, Geochemistry: Exploration, Environment, Analysis, 10(1), pp. 27–74. doi: 10.1144/1467-7873/09-210.

Hall, R. (2002) ‘Cenozoic geological and plate tectonic evolution of SE Asia and the SW Pacific: computer-based reconstructions, model and animations’, Journal of Asian Earth Sciences, 20(4), pp. 353–431. doi: 10.1016/S1367-9120(01)00069-4.

Hamilton, W. (1979) Tectonics of the Indonesian region. U.S. Geological Survey. doi: 10.3133/pp1078.

Hedenquist, J. W. and Arribas, A. (2017) der features relevant to exploration and asses‘Epithermal ore deposits: first-or sment’, in Proceeding of 14th SGA Biennial Meeting: Mineral Resources to Discover - Volume 1. Quebec, Canada: Society for Geology Applied to Mineral Deposits, pp. 47–50.

Hutchison, C. S. (1989) ‘Geological evolution of South-east Asia’, in. Clarendon Press, p. 368.

IAGI-MGEI (2015) ‘Indonesia mineral endowment’, in IAGI (Indonesian Association of Geologists) on Road Map of Indonesian Mining. IAGI & MGEI, p. 35.

Joyce, A. S. (1984) Geochemical exploration. Glenside: Australian Mineral Foundation.

Katili, J. A. (1978) ‘Past and present geotectonic position of Sulawesi, Indonesia’, Tectonophysics, 45(4), pp. 289–322.

doi: 10.1016/0040-1951(78)90166-X.

Kirkwood, C., Everett, P., Ferreira, A. and Lister, B. (2016) ‘Stream sediment geochemistry as a tool for enhancing geological understanding: An overview of new data from south west England’, Journal of Geochemical Exploration, 163, pp. 28–40. doi: 10.1016/j.gexplo.2016.01.010. (2021) Gold price today, Available at: (Accessed: 8 May 2021).

Levinson, A. A. (1974) Introduction to exploration geochemistry. United States: Applied Publishing.

Maryono, A., Harrison, R. L., Cooke, D. R., Rompo, I. and Hoschke, T. G. (2018) ‘Tectonics and geology of porphyry Cu-Au deposits along the Eastern Sunda Magmatic Arc, Indonesia’, Economic Geology, 113(1), pp. 7–38. doi: 10.5382/econgeo.2018.4542.

Maula, S. and Levet, B. K. (1996) ‘Porphyry copper-gold signatures and the discovery of the Batu Hijau deposit, Sumbawa, Indonesia’, in Conference on Porphyry Related Copper and Gold Deposits of the Asia Pacific Region. Cairns, Australia: Australian Mineral Foundation, pp. 8.1-8.13.

Meldrum, S. J., Aquino, R. S., Gonzales, R. I., Burke, R. J., Suyadi, A., Irianto, B. and Clarke, D. S. (1994) ‘The Batu Hijau porphyry copper-gold deposit, Sumbawa Island, Indonesia’, Journal of Geochemical Exploration, 50(1–3), pp. 203–220. doi: 10.1016/0375-6742(94)90025-6.

Prihatmoko, S. and Idrus, A. (2020) ‘Low-sulfidation epithermal gold deposits in Java, Indonesia: Characteristics and linkage to the volcano-tectonic setting’, Ore Geology Reviews, 121, p. 103490. doi: 10.1016/j.oregeorev.2020.103490.

Ranasinghe, P. N., Fernando, G. W. A. R., Dissanayake, C. B., Rupasinghe, M. S. and Witter, D. L. (2009) ‘Statistical evaluation of stream sediment geochemistry in interpreting the river catchment of high-grade metamorphic terrains’, Journal of Geochemical Exploration, 103(2–3), pp. 97–114. doi: 10.1016/j.gexplo.2009.07.003.

Ridley, J. (2013) Ore deposit geology. Cambridge: Cambridge University Press.

Robb, L. (2005) Introduction to ore-forming processes. Oxford: Wiley-Blackwell.

Rose, A. W., Hawks, H. E. and Webb, J. H. (1979) Geochemistry in mineral exploration. New York: Academic Press.

Shafiee, S. and Topal, E. (2010) ‘An overview of global gold market and gold price forecasting’, Resources Policy, 35(3), pp. 178–189. doi: 10.1016/j.resourpol.2010.05.004.

Simmons, S. F., White, N. C. and John, D. A. (2005) ‘Geological characteristics of epithermal precious and base metal deposits’, in Hedenquist, J. W. et al. (eds) One Hundredth Anniversary Volume. Society of Economic Geologists, pp. 485–522. doi: 10.5382/AV100.16.

Sun, X., Zheng, Y., Wang, C., Zhao, Z. and Geng, X. (2016) ‘Identifying geochemical anomalies associated with Sb–Au–Pb–Zn–Ag mineralization in North Himalaya, southern Tibet’, Ore Geology Reviews, 73, pp. 1–12. doi: 10.1016/j.oregeorev.2015.10.020.

Supriatna, S. (1980) ‘Peta geologi lembar Morotai Skala 1:250.000’. Bandung: Pusat Penelitian dan Pengembangan Geologi (P3G), p. 1.

Theobald, P. K., Eppinger, R. G., Turner, R. L. and Shiquan, S. (1991) ‘The effect of scale on the interpretation of geochemical anomalies’, Journal of Geochemical Exploration, 40(1–3), pp. 9–23.

Weng, F., Chen, Y., Wang, Z., Hou, M., Luo, J. and Tian, Z. (2020) ‘Gold price forecasting research based on an improved online extreme learning machine algorithm’, Journal of Ambient Intelligence and Humanized Computing, 11(10), pp. 4101–4111. doi: 10.1007/s12652-020-01682-z.

White, N. C. and Hedenquist, J. W. (1995) ‘Epithermal gold deposits: Styles, characteristics, and exploration’, SEG Newsletter, (23), pp. 1, 9–13.

Xuejing, X. and Xueqiu, W. (1991) ‘Geochemical exploration for gold: a new approach to an old problem’, Journal of Geochemical Exploration, 40(1–3), pp. 25–48. doi: 10.1016/0375-6742(91)90030-X.

Yilmaz, H., Ghezelbash, R., Cohen, D. R., Sari, R., Sönmez, F. N. and Maghsoudi, A. (2020) ‘Comparison between the geochemical response of BLEG and fine fraction stream sediments to mineralization in the Eastern Black Sea region, Turkey’, Journal of Geochemical Exploration, 217, p. 106609. doi: 10.1016/j.gexplo.2020.106609.

Yilmaz, H., Cohen, D. R. and Sonmez, F. N. (2017) ‘Comparison between the effectiveness of regional BLEG and −80# stream sediment geochemistry in detection of precious and base metal mineral deposits in Western Turkey’, Journal of Geochemical Exploration, 181, pp. 69–80. doi: 10.1016/j.gexplo.2017.07.003.

Yousef, I. and Shehadeh, E. (2020) ‘The impact of COVID-19 on gold price volatility’, International Journal of Economics and Business Administration, VIII(Issue 4), pp. 353–364. doi: 10.35808/ijeba/592.