January 9, 2007. Joint University of Costa Roca / US National Science Foundation fieldtrip to the Talamanca Mountains of Costa Rica. We leave San Jose early in the morning with two vehicles, a bus and a pickup truck. I ride in the bus, choosing a seat near the middle. We head south along the Pan American Highway, which is a two lane road of similar quality to Route 9W here in New York, which is to say fairly decent. But like all two lane roads, it puts us at the mercy of slow traffic, for passing (especially with a bus) is always tricky. Our driver, Jose, is extremely patient and careful, so we have absolutely no problems during the entire trip. The day is clear and sunny, but cool - maybe 75 deg F - and the vistas are very beautiful.

Stop 1A. [9:39.325N 83:58.314W 1493m NAD27-Cental Datum] We drive down a lane, park behind a masonry yard, and then walk down a lane past a coffee plantation. The lane is lined with trees, many of which support blooming orchids and other epiphytes. A small stream flows beside the road. A small quarry has been cut into the hillside. It does not expose solid rock but rather boulders and larger blocks mixed in with dirt. The geologists explain to me that this is often the closest that one comes to bedrock in the tropics. Weathering has eaten away at the bedrock, following cracks and joints, and only the most solid portions have escaped being turned to gunk. The rock is light in color, and tentatively identified as a granodiorite. It contains small patches of basalt, regions termed 'mafic enclaves'.

I notice a shelf about halfway up the hill, and climb up to it following a gulley. I can feel the altitude - about 1500 meters. I've grown too used to sea level! The shelf is quite eroded, and has similar boulders and dirt to what I've already seen. I follow it for a few tens of meters and then follow another gulley to the quarry floor. There's more vegetation along that gulley and I get covered with small burrs, which take a long time to pick off. I walk further along the lane, which ascends up the hill adjacent to the quarry. Basalt is outcropping on the road bed. About an hour.

Stop 1B. [9:36.147N 83:47.384W 2879m NAD27-Cental Datum] We stop at another quarry that is higher up on the Talamancas, right on the Pan American Highway. Real rock is exposed here, a black and glassy dacite. The main face of the quarry is out of reach, owing to a lake that fills the quarry. But it appears to have been worked in several stages, with the upper portion being much mossier than the lower. A few indistinct dikes appear to cut across the quarry face. I walk along a path that follows the highway, from one end of the quarry to the other. There is a lot of interesting vegetation here, shrubs and so forth that I have never seen before. Some rocks are covered with bright white lichen. I find a fist-sized piece of quartz, which I later show to the geologists. They say that the quarry is well known for hydrothermal quarry deposits. About a half hour.

Stop 1C. [9:34.417N 83:45.440W 3301m NAD27-Cental Datum] We are now quite high up in the Talamanca Mountains, and still along the Pam American Highway. We climb up a trail on the east side of the highway that leads up to a rocky knob about 100 meters above road level. It's quite a huff! The trail is old, and not well-maintained, but was built well and is still quite serviceable. The vegetation includes mostly shrubs that appear adapted do dry, windy weather. An olivine bearing basalt is exposed on the top. We are rather clouded in here. Patches of mist are rolling over the hill below us, although overall the visibility is good. After descenting back down to road level, I examine sandstones outcropping on the side of the road. I find a few small casts of gastropods, which I show to Teresita, who is a paleontologist. About an hour.

Stop 1D. [9:32:556N 83:42:701W 2664m NAD27-Cental Datum] We continue south along the Pan American Highway, and stop along the side of a ridge. Once side of the road has a steep cliff, the other drops off into a deep valley. The view into and across the valley is extraordinarily beautiful. Extremely large tropical trees, green and yellow in color, dominate the hillside below us. The distance peaks of the Talamancas, across the valley, are bright green with patches of white clouds. The relief, which is very substantial, is accentuated by the low sun of the late afternoon. It’s getting cold: my breath is misting. The rocks of the cliff face include a fine grained aplitic granite, and some basalts, too. About half an hour.

January 10, 2007. We spent the night at the Savegre Hotel de la Montana, an eco-resort located 10 km from the Pan American Highway down a very steep one-lane road that winds down the valley of the Rio Savegre. The hotel grounds are adorned with many interesting kinds of trees, shrubs and flowers. Many hummingbirds have been attracted by feeders, and I spend a long time watching them in the fading light of the evening. The hotel is organized with a central building surrounded by cabins. Vadim Levin and I stay in Room 107.

Stop 2A. [9:32:940N 83:48.450W 2121m NAD27-Cental Datum] In the early morning I walk from the hotel down to the Rio Savegre, which is a small, fast-moving stream that flows over numerous boulders. I stand for a while on the hotel's bridge admiring the cascades and the plants by the river, and then continue onward. I pass several horses that are standing placidly beside the road, unattended and untethered. They are feeding on hay that just has been dropped off for them. I see a sign pointing downhill for a waterfall, and walk in that direction as far a second bridge. The waterfall is nowhere in sight, and my time is very limited, so I turn back. The rays of the sun are lighting up the valley walls but have not yet reached the bottom where I stand, and the air is chilly. About half an hour.

Stop 2B. [9:13.254N 83:17.559W 782m NAD27-Cental Datum]. At last, some hot weather! We have driven further south along the Pan American Highway, out of the Talamanca Mountains into the Valle del General, located just west of the mountains. This area is notable for its red, heavily-weathered laterite soil, on which pineapples are grown. We leave the highway at the town of Buenos Aires, and head east and then northeast along a well-maintained dirt road that follows a ridge crest. We stop at a high point that commands an extraordinary view of the west flank of the Talamancas. We can see many heavily dissected alluvial fans that emerge from the mountains. Indeed, we are standing on one. Vadim, Tom Vogel and I walk further east along the road, mostly to get some exercise. We pass an enormous gulley that has eaten away part of the road and the hillside that supports it. It's hard to imaging the watershed of the ridge, which is tiny, could have supplied enough water to cause so much damage. I suppose that it occurred during a hurricane or similar deluge. A little further along the road, we come across a dike exposed in the road bed. It is extremely weathered; hardly any solid rock is left. The alluvium in its vicinity contains a network of hydrothermal veins. About two hours.

Stop 2C. [9:12.957N 83:18,994W 469m NAD27-Cental Datum]. We follow another dirt road, also in the Buenos Aires region, down to the Zeibo River, which is wide and has a bed of boulders. We walk across the slender, one-lane suspension bridge by foot, and afterward the bus follows us. It can barely fit, and the bridge sags by almost a meter.

Stop 2D. [9:15.928N 83:17.613W 677m NAD27-Cental Datum]. We have driven a few kilometers upstream, following the north bank of the Zeibo River, until we come to a ford. The bus stops here, and we cross the river by a suspension foot bridge located just upstream of the ford. Several teenagers are swimming in the stream. The pile of boulders piled upstream of the ford have created a nice water hole. The quarry that we have come to see is located just beyond the ford. We scramble under a barbed wire fence. No bedrock is visible, just angular boulders of granitic composition in a hillside. We suppose that a granitic pluton is located within the ridge. After viewing the quarry I walk along the road for a bit. I pass a group of cows and calves. They have very beautiful tan hide. I am told that they are an Indian variety, chosen to be able to endure heat. About an hour.

Stop 2C. The bridge across the Zeibo, again.

January 11, 2007. One again, we spent the night at the Savegre Hotel de la Montana. I spot some vultures in a dead tree in the morning as we are getting ready to go. We head back north, and cross over to the east (Caribbean) side of Costa Rica.

Stop 3A. [9:56.276N 83:46.624W 1659m NAD27-Cental Datum]. We stop along Route 230 a little east of the town of Pacayas, on the south flank of the Irazu-Turrialba volcanoes. The steep terrain contains many small farms whose fields, in vaiuos stages of planting and plowing, make an interesting quilt work. This area has been affected by a large post-Pleistocene landslide. About a half hour.

Stop 3B. [9:56.626N 83:42.324W 951m NAD27-Cental Datum]. We stop again, further east along Route 230, to view some hummocky terrain in the valley to the south that is a landslide remnant. About 15 minutes.

Stop 3C. [10:02.318N 83:32.787W 722m NAD27-Cental Datum]. We visit a soccer field near the town of Guayacan, just off of Route 10. A few chickens are pecking away at dust beside the field, but they scurry away as we approach. A basaltic outcrop used to be visible before the field was built, but is now covered over. But some blocks of the rock are heaped up near the edge of the field. The geologists crack several apart with sledge hammers, and carefully examine the shards, looking for olivine crystals. One or two are found. I collect the shards, which are razor sharp, and pile them between two boulders, as a favor to the feet of the next soccer teams to use the field. I walk to the back of the soccer field, where I have a good view of the northwestern skyline, which is dominated by the sloping profile of a volcano. About an hour.

Stop 3D. [9:58.898N 83:13.059W 74m NAD27-Cental Datum]. We are in the Caribbean lowlands now, along Route 32 near the town of Boston. We drive down a muddy and marginally-passable dirt road as far as we dare, and then walk the rest of the way to a stream. Only a little water is flowing; the stream bed is mostly rounded boulders eroded out of the eastern Talamancas. Most of the boulders are igneous rock, with a few sediments as well. I find among them a fossil bivalve, perhaps an inch long, which I later give to Teresita. Some sandstones outcrop along the riverbank. We walk upstream along the river bed, crossing the running water from time to time. I find a straight stick to use as a staff. Mostly I tiptoe from boulder to boulder, but once or twice have to get my feet wet. The vegetation along the stream bank is very luxuriant. On the way back, I pass two policemen who have come to investigate - us, I guess! Or maybe not, for they are inspecting a logging operation as I pass them. In any case, they are friendly and we greet each other with a 'bueno' as I walk by. About an hour.

January 11, 2007. We head back to San Jose, today, having spent the night at the Hotel Suerre in Guapiles. We make only one brief stop, in the pouring rain, where the road (Route 32) crosses the Rio Sucio. I run out of the bus with my umbrella, and peer down into the gorge. The river looks very powerful. Its water is a yellow-tan color- from mud, I guess - and rocks protruding from the flow are stained that color, too. We arrive back in San Jose in the early afternoon.