Mekanisme erupsi ignimbrit Kaldera Maninjau, Sumatera Barat

Agung Pribadi, Eddy Mulyadi, Indyo Pratomo

Abstract


http://dx.doi.org/10.17014/ijog.vol2no1.20073

Maninjau is a large collapsed caldera that was resulted from a large eruption of silicic pyroclastic material (220-250 km3), and was distributed to more than 75 km away from the source. Field observations have provided a good understanding to the eruptive mechanism of the Maninjau caldera formation, in respect to their stratigraphy, sedimentology and geochronology of the eruptive products. Two formations have been identifi ed, those are: the Maninjau Formation, comprising a sequence of ignimbrite and surge units erupted from the Maninjau Caldera, and the Malalak Formation as a prominent andesitic fall unit likely derived from the Singgalang - Tandikat Volcano that overlies the Maninjau Formation. The variable velocity of the fl ows suggests that the Maninjau eruption initiated by violent. The later phases of the eruption became more violent and associated with caldera collapse.

 


Keywords


caldera collapse; eruptive sequence; ignimbrite; eruptive mechanism; Maninjau

References


Bellier, O. and Sebrier, M., 1994. Relationship between tectonism and volcanism along the Great Sumatran Fault zone deduced by SPOT image analyses. Tectonophysics, 223, p. 215-231.

Cas, R.A.F. and Wright, J.V., 1987. Volcanic Successions: modern and ancient. Allen & Unwin, London, 528 pp.

Cole, P.D., Guest, J.E., and Duncan, A.M., 1993. The emplacement of intermediate volume ignimbrite: A case study from Roccamonfi na Volcano, Southern Italy, Bull. Volcanol., 55, p. 467-480.

Freud, A. and Schmincke, H.U., 1985. Lithic rich segregation bodies in pyroclastic fl ows deposits of Laacher See Volcano. J. Volcanol. Geotherm. Res., 25, p. 193-224.

Freud, A. and Schmincke, H.U., 1986. Mechanism of small volume pyroclastic fl ows at Laacher See (East Eiffel, Germany). Bull. Volcanol., 48, p. 39-59.

Kastowo, R.L. danLeo, G.W., 1973. Peta Geologi Lembar Padang, Sumatera. Skala 1:250.000. Direk. Geologi.

Kusumadinata, K., 1979. Data Dasar Gunungapi Indonesia.

Direktorat Vulkanologi. 819 h.

Ninkovick, D., Shackleton, N.J., Abdel-Monem, A.A., Obradovich, J.D., and Izett, G., 1978a. K-Ar-age of the late Pleistocene eruption of Toba, North Sumatera. Nature, 276, p. 574-577.

Ninkovick, D., Sparks, R.S.J., and Ledbetter, M.T., 1978b. The exceptional magnitude and intensity of the Toba eruption, Sumatera: an example of the use of deep-sea tephra layers as a geological tool. Bull. Volcanol., 41, p. 286-298.

Nishimura, S., Sasajima, S., Hirooka, K., Thio, K.H., and Hehuwat, F., 1978. Radiometric ages of volcanic products in Sunda Arc, CCOP/SEATAR workshop, March 1978. Parapat.

Purbo-Hadiwidjojo, M.M., Sjahrudin, M.L., and Suparka, S., 1979. The volcano-tectonic history of the Maninjau Caldera, Western Sumatera, Indonesia. In: W.J.M. Van der Linden, (ed): Fixism, mobilism or relativism: Van Bemmelen’s search for harmony. Geol. Mijnbouw, 58, p. 193-200.

Rose, W.I. dan Chesner, C.A., 1987. Dispersal of ash in the great Toba eruption, 75 ka. Geology, 15, p. 913-917.

Shane, P., Westgate, J.A., Williams, M., and Korisettar, R., 1995. New Geochemical evidence for the youngest Toba tuff in India. Quarternary Research, 44, p. 200-204.

Sparks, R.S.J. and Walker G.P.L., 1973. The ground surge deposit: a third type of pyroclastic surge deposit. Nature, 241, p. 62-64.

Sparks, R.S.J., Self, S., and Walker G.P.L., 1973. Products of Ignimbrite eruptions. Geology, 1, p. 115-119.

van Bemmelen, R.W., 1949. The geology of Indonesia, Martinus Nijhoff, The Hague, Netherland, 1, 732 p.

van Padang, N., 1951. Catalogue of volcanic activity and solfatara fields, Part I, Indonesia. International Volcanological Association, Napoli, Italy.

Verbeek, R.D.M., 1883. Topografische en Geologische beschrijving an een gedeelte van Sumatra’s Westkust. Mijnw. Nederl. Ind. Jaarb., 10, p. 457-469.

Westerveld, J., 1953. Eruptions of acid pumice tuffs and related phenomoena along the Great Sumatran Fault- through System. Proceeds. 7th Pacifi c Sci. Congress, vol. 2, Auckland and Cristchurch, p. 411-438.


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