Bleak hard days are followed by happy sunny ones, and today was the latter. Irvan had been in contact with the local BMKG office and they told him that they would meet us at the hotel at 8:30 am. I was expecting maybe two people, but instead we had the two division leaders and eight members of the staff. They wanted to spend the day with us, and even brought an extra driver so he could take over from me and allow me to relax in the back seat. Nice :)
The objective of the trip was to visit the most recent UNESCO Geopark in Indonesia: the Meratus Mountains Geopark. The purpose of these geoparks is to use some unique geologic feature to foster tourism, develop new industries such as handcrafts or restaurants, and provide a place where families can go enjoy the weekend (for example Meratus has a small zoo and a swimming pool where kids can have a great time). The uniqueness of these mountains is that they are a subduction zone complex, with a recognizable ophiolite sequence, so the buzzword is serpentinite.
Before getting to the mountains, however, we stopped in the alluvial plain where for more than a thousand years miners have been panning for diamonds within the alluvial gravels. Diamonds? Where the heck would diamonds be coming from? Diamonds are found in kimberlite breccia pipes, a rare type of volcano that brings mantle materials from great depths (more than 150 km) in the form of a pyroclastic suspension supported by the exsolution of large amounts carbon dioxide from the mantle. They are generally found cutting through the old cores of continents (cratons) like are found in Africa, Brazil, or Australia. None of that old stuff here in Borneo, and no known kimberlite pipes either, so the origin of the diamonds found as placer rarities in the gravels is a mystery. North Australia would be the closest known source, but that is a long way from Borneo.
Once in the Visitors Center our small battalion of smartly dressed BMKG companions attracted immediate attention from the park supervisor, who personally escorted us through the geology museum and insisted on showing us two beautiful documentaries about the park. At the museum I learnt that coal is found in both Eocene and Oligocene units, whereas oil and gas is produced from Miocene units. You may remember that when we were in Bontang, to the north, they are also producing natural gas. This natural gas comes from the Eocene coal and is mostly methane, which is then transformed into methanol.
The park supervisor then hopped on his motorcycle and led us up, up, and up until we were in the crest of a ridge formed by a wedge of serpentinite, from which one enjoys a breathtaking panorama over the Meratus Mountains. The Dutch found this to be the perfect place for building a small colony from which the coal extraction and the coffee plantations could be coordinated (at arms length, because they didn't want to spoil the beauty of the place). The houses they built have been renovated and are now museum pieces, where ample windows suggest of leisurely life interrupted by badminton matches and plunges in the spring-fed pool.
After saying goodbye to our gracious host we headed for lunch at a place that specializes in grilled fish with a tasty sauce. Delicious!
Back in Banjarmasir I went for a walk along the banks of one of the tributaries of the Bari River that cuts across the heart of the city. It was a fun lively river promenade, but the real spectacle is the river boats market that sets early in the morning. If I wake up early I might go there tomorrow to check it out.
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