A reconnaissance on the use of the speleothems in Korean limestone caves to retrospective study on the regional climate change for the recent and geologic past

摘要

More than 1,000 limestone caves are extensively developed in Gangwon-do and Chungcheongbuk-do, Korea. A variety of numerous speleothems are actively growing in these caves today. A potential to use speleothems as regional paleoclimate proxy was explored by analyzing soda straw, stalactite and stalagmite. These proxy recorders that have grown during the past several decades were investigated using the presence of excess210Pb. Most specimens collected from six limestone caves were found to have an excess210Pb, indicating that they are less than about 100 yrs old. This excess210Pb was employed to estimate the growth rate for a tubular “soda straw” that yielded a longitudinal growth rate of 1.7 mm/yr past 60 years. Coeval decrease in δ13C values of the soda straw, spanning the time period of about 1930–1995 AD, may reflect the carbon isotope ratio of about 1930–1995 AD, may reflect the carbon isotope ratio of atmospheric CO2 for the same period. Studies on fine scale variations in the isotopic composition of recent speleothems along with age control using210Pb excess method from the speleothems in Korean limestone caves promise a great potential for the reconstruction of climate and environmental changes during the past hundred years or so.