Expedition 2000 Addendum
to Caves of Gunung Buda 1997
Gunung Buda Expedition 2000
Addendum to Caves of Gunung Buda 1997
Paleomagnetic Sediments from the
Gunung Buda Caves
Andrea Futrell, Mike Futrell, Ira D. Sasowsky
Oriented samples of clastic sediments found in the Buda caves were collected for paleomagnetic analysis. This technique allows the determination of minimum ages for the development of the caves, through comparison with the global paleomagnetic timescale. A total of 36 samples were collected, with a duplicate at each position. Samples came from Green Cathedral Cave, Snailshell Cave, Cin Cin Cave, Mojo Cave, and Upper Turtle Cave, and spanned an elevation from 99 to 310 meters amsl. The samples were all clay or silt, with a wide variety of colors, indicating numerous sources for the sediments. Samples were subjected to alternating field demagnetization to reveal the underlying paleomagnetic signal. The majority of the samples showed very clean demagnetization paths, indicating a single magnetic component. Anormal polarity with a very shallow inclination (as expected for this region) was shown in the bulk of the samples.
Preliminary anlysis indicates samples with a reversed magnetic component from an elevation of 152 meters amsl in Cin Cin Cave. These samples also have a Normal polarity overprint, suggesting two magnetic carriers. These samples are overlain by apparently normal sediments. If this analysis is correct, it suggests that the sediments were deposited (at the earliest) during the younger end of the Jaramillo Event, meaning an age for the cave of more than 910,000 years. Possible reversed polarity sedmients were also noted in Mojo Cave at an elevation of 209 meters amsl. When combined with paleohydrologic data, and a GIS (geographic information system) analysis of the Gunung Buda, we hope to be able to closely determine the age of the caves in the massif.
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