1. A snapshot of the climate in the Middle Pleistocene inferred from a stalagmite from central Japan
- Author
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Masataka Sakai, Masako Hori, Ryu Uemura, Bassam Ghaleb, Daniele L. Pinti, Mahiro Yumiba, Masafumi Murayama, and Akihiro Kano
- Subjects
Stalagmite ,Middle Pleistocene ,Stable isotopes ,Climate record ,Uranium disequilibrium method ,Science ,Geology ,QE1-996.5 - Abstract
Abstract Stalagmites are useful archives in reconstructing paleoclimates: most paleoclimate studies used stalagmites that are distributed in specific locations and ages. We examined a stalagmite (GYM-1) collected from Nara Prefecture, central Japan, where limestone areas are limited. Applying 238U–234U method, the ages of GYM-1 were determined as 744 ± 70 to 677 ± 74 ka (based only on analytical uncertainties, 1σ). Even assuming a 10% uncertainty in the initial activity of 234U/238U, (234U/238U)0, this age could be still older than 460 ka. Temperatures calculated based on δD in the fluid inclusions and δ18O in the calcium carbonate ranged from 9.0 to 11.9 °C (10.8 ± 0.9 °C on average) or from 6.0 to 9.1 °C (7.9 ± 0.9 °C on average) depending on the equation. The estimated temperature suggests that GYM-1 formed during an interglacial period of the Middle Pleistocene. Synchronous behavior of isotopic values with lamination likely reflects seasonal temperature in a highly ventilated cave system.
- Published
- 2024
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