Patterson E W, Skiba V, Wolf A, Griffiths M L, McGee D, Bùi T N, Trần M X, Đinh T H, Đỗ-Trọng Q, Goldsmith G R, Ersek V, Johnson K R
Department of Earth System Science, University of California, Irvine, CA, USA.
Department of Environmental Science, William Paterson University, Wayne, NJ, USA.
Nat Commun. 2024 Oct 21;15(1):9064. doi: 10.1038/s41467-024-53422-y.
Oxygen isotopes (δO) are the most commonly utilized speleothem proxy and have provided many foundational records of paleoclimate. Thus, understanding processes affecting speleothem δO is crucial. Yet, prior calcite precipitation (PCP), a process driven by local hydrology, is a widely ignored control of speleothem δO. Here we investigate the effects of PCP on a stalagmite δO record from central Vietnam, spanning 45 - 4 ka. We employ a geochemical model that utilizes speleothem Mg/Ca and cave monitoring data to correct the δO record for PCP effects. The resulting record exhibits improved agreement with regional speleothem δO records and climate model simulations, suggesting that the corrected record more accurately reflects precipitation δO (δO). Without considering PCP, our interpretations of the δO record would have been misleading. To avoid misinterpretations of speleothem δO, our results emphasize the necessity of considering PCP as a significant driver of speleothem δO.
氧同位素（δO）是最常用的洞穴石笋代用指标，已提供了许多古气候的基础记录。因此，了解影响洞穴石笋δO的过程至关重要。然而，方解石沉淀前过程（PCP），这一由当地水文驱动的过程，是洞穴石笋δO中一个被广泛忽视的控制因素。在此，我们研究了PCP对越南中部一根跨越45 - 4千年前的石笋δO记录的影响。我们采用了一个地球化学模型，该模型利用洞穴石笋的Mg/Ca和洞穴监测数据来校正PCP效应的δO记录。所得记录与区域洞穴石笋δO记录及气候模型模拟结果的一致性有所提高，这表明校正后的记录更准确地反映了降水δO（δO）。若不考虑PCP，我们对δO记录的解读将会产生误导。为避免对洞穴石笋δO的错误解读，我们的研究结果强调了将PCP视为洞穴石笋δO的一个重要驱动因素的必要性。
