KETELITIAN PADA PENANGGALAN DALAM STUDI IKLIM MASA LAMPAU DENGAN MENGGUNAKAN CONTOH KORAL MODERN

Sri Yudawati Cahyarini

doi:10.14203/risetgeotam2015.v25.168

KETELITIAN PADA PENANGGALAN DALAM STUDI IKLIM MASA LAMPAU DENGAN MENGGUNAKAN CONTOH KORAL MODERN

Sri Yudawati Cahyarini

Abstract

Dalam studi iklim masa lampau menggunakan arsip iklim (seperti koral, sedimen, pohon dan lain-lain), penentuan penanggalan (membangun kronologi) merupakan hal penting karena kesalahan dalam penanggalan dapat menjadi kesalahan dalam interpretasi iklim. Studi ini membahas penanggalan untuk studi iklim masa lampau dengan menggunakan arsip iklim koral. Tujuan penelitian ini untuk mengidentifikasi permasalahan yang muncul dalam membangun kronologi dan ketelitian dalam pembangunan kronologi berdasarkan perlapisan densitas koral. Dalam penelitian ini digunakan contoh koral Porites dari Pulau Jukung, Kepulauan Seribu. Analisis densitas koral dilakukan dengan CoralXDS dan kandungan kimia Sr/Ca dengan ICP OES. Hasil yang diperoleh menunjukkan penentuan kronologi tahunan berdasarkan densitas dalam satu koloni koral namun berbeda garis transeknya dapat menghasilkan perbedaan kronologi. Asumsi rata-rata pertumbuhan tahunan koral yang merupakan salah satu data input dalam perangkat lunak CoralXDS merupakan salah satu faktor yang mempengaruhi kronologi berdasarkan densitas koral. Permasalahan pembangunan kronologi tahunan berdasarkan densitas koral dapat diatasi dengan menggunakan data kimia koral.

In paleoclimate studies using climatic archives (such as corals, sediments, tree, etc.), chronology development is important because the error in chronology development may generate an error in the interpretation of climate. This study discussed chronology development in paleoclimate reconstruction using coral as climate archive. The objectives of this study is to identify the problems that arise in chronology development based on coral density band and its accuracy. In this study a Porites coral from Jukung Island, Seribu Islands complex is used as an example. CoralXDS software is used to coral density analysis and coral Sr/Ca is analyzed using ICP OES. The results show that the determination of the annual chronology based on coral density in the same coral colonies but different transect line can produce differences in chronology. The assumption of average annual growth of coral, which is one of the input data in the CoralXDS software, serves as one of the factors that affect the chronology based on the density of coral. Annual chronology development problems based on the density of corals can be overcome by using chemical data content in coral (e.g Sr/Ca).

Keywords

chronology, coral density, Sr/Ca

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DOI: http://dx.doi.org/10.14203/risetgeotam2015.v25.168