Gunung Padang

Gunung Padang is an archaeological site located in Karyamukti, West Java, Indonesia, 50 kilometres (31 mi) southwest of Cianjur. Located at 885 metres (2,904 ft) above sea level, the site covers a hill—an extinct volcano—in a series of five terraces bordered by retaining walls of stone that are accessed by 370 successive andesite steps rising about 95 metres (312 ft). It is covered with massive hexagonal stone columns of volcanic origin. The Sundanese people consider the site sacred and believe it was the result of King Siliwangi's attempt to build a palace in one night.

Gunung Padang consists of a series of five artificial terraces—one rectangular and four trapezoidal—that occur, in succession, at progressively higher elevations. These terraces also diminish in size as elevation increases, with the first being the lowest and largest, and the fifth being the highest and smallest. The terraces are aligned along a central longitudinal NW–SE axis. They are artificial platforms created by lowering elevated areas and filling in depressions until a flat surface was achieved. The perimeters of the terraces feature retaining walls constructed from volcanic polygonal columns, stacked horizontally and erected vertically as posts. Access to the complex is provided by a central stairway with 370 steps, an inclination of 45 degrees, and a length of 110 m (360 ft).

The Gunung Padang region consists of steep-sided hills with an altitude of 800–1,200 metres (2,600–3,900 ft) above sea level. As seen in satellite images and digital terrain models, Gunung Padang is a small hill partially surrounded by the curved ridge crest of Gunung Empet. The north-facing slopes of Gunung Empet form a steep escarpment facing Gunung Padang and the partial rim of a deeply eroded, circular basin. The south-facing slopes are significantly gentler. North of Gunung Padang, there are Gunung Malang, Pasir Domas, and Pasir Pogor. Gunung Malang is located in the center of this deeply dissected basin. Gunung Padang lies somewhat on the edge of this basin, at the tip of a narrow ridge that continues southward and merges with the northern slope of Gunung Empet. According to the Cianjur geological map by Sujatmiko, the bedrock of the Gunung Padang area consist of basaltic andesite volcanic rocks regionally classified as the Tuffaceous Breccia, Lava, Sandstone, and Conglomerate. These volcanic rocks are intruded by igneous rocks called the Homblenda Pasir Pogor Andesite Intrusion. Based on K–Ar dating from Pertamina, the Homblenda Pasir Pogor Andesite Intrusion is inferred to be about 32.3 ± 0.3 million years old. Based on local field studies, regional geology, and local geomorphology, the circular basin within which Gunung Padang lies is inferred to be the caldera of an extinct, deeply eroded composite volcano, called the Karyamukti composite paleovolcano, which lies at the intersection of the Cimandiri fault (WNW – ENE) and the Gede-Cikondang fault (NNW – SSE).

Gunung Padang, on which the terraces of the Gunung Padang Site lie, is made up of hydrothermally altered volcanic rocks consisting of lava flows alternating with volcanic breccia that are intruded by andesite intrusive rocks. These volcanic rocks, which have been hydrothermally altered to quartz, pyrite, and kaolinite, are part of the deeply eroded Karyamukti composite paleovolcano. Because of their pervasive alteration, they are structurally weak and form an unstable base to Gunung Padang. The intrusive andesites, which correlate with the Homblenda Pasir Pogor Andesite Intrusion, form the top of Gunung Padang. This consists of andesite porphyry exhibiting well-developed columnar jointing, which forms trigonal to hexagonal stone columns that vary in shape and symmetry and in length from 1–3 metres (3 ft 3 in – 9 ft 10 in). The columnar jointing has formed perpendicular to the largely vertical sides of the igneous intrusion. The andesite porphyry consists of plagioclase and pyroxene phenocrysts surrounded by an aphanitic groundmass of volcanic glass. These stone columns have been used as ready-made blocks in the construction of the megaliths at the Gunung Padang Site.

Because of the weak and unstable foundation formed by the hydrothermally altered Karyamukti volcanic rocks, the summit of Gunung Padang partially collapsed during the Late Pleistocene, prior to the creation of the Gunung Padang Site. Evidence of this past collapse can be seen in the deposits of ancient landslides that underlie its western, upper eastern, and northern slopes and northeastern foot. In exposures of these deposits, repeated landslides can be seen to have tilted the long axis of the stone columns parallel to these slopes. This history indicates the continued collapse of Gunung Padang as well as the threats this has created for the archeological site.

Along the eastern side of Gunung Padang, the andesite porphyry and associated stone columns are relatively unweathered, in contrast to the stone columns of the western slope, which have been worn by spheroidal weathering. Some stone columns have weathered further into reddish-brown clay, and some are encased within clay crusts. These clay crusts, which have been mistaken for manmade mortar, are natural weathering rinds formed as a result of weathering penetrating inward from the columnar jointing.

Dutch historian Rogier Verbeek mentioned the existence of the Gunung Padang site in his book Oudheden van Java: lijst der voornaamste overblijfselen uit den Hindoetijd op Java, based on a visit and report by M. De Corte in 1890

—Rogier Verbeek, Oudheden van Java,1891.