NOAA/WDS Paleoclimatology - Antro del Corchia Geochemical Data from 393400 to 125400 Cal Yr BP

The age structure and stable isotope composition of a stalagmite (CC1) from an upland cave in central-western Italy were studied to investigate regional response to global climatic changes. Four growth phases are constrained by 28 thermal ionization and multi-collector inductively coupled plasma mass spectrometry Th–U ages and reveal intermittent deposition through the period between Marine Isotope Stage (MIS) 11 and 3 (∼380 and ∼43 kyr). Most of the growth took place between ∼380 and ∼280 kyr, a period punctuated briefly by a hiatus in deposition through the glacial maximum of MIS 10. Growth was terminated abruptly at 280 kyr just prior to the MIS 8 glacial maximum. With a present-day chamber temperature of 7.5 °C, the timing of hiatuses close to these glacial maxima point to freezing conditions at the time. No deposition was recorded through the entirety of MIS 7 and most of MIS 6, whilst two minor growth phases occurred at ∼141–125 and ∼43 kyr. Growth at 141 kyr indicates temperatures >0 °C at a time when MIS 6 ice volumes were close to their maximum. High stable carbon isotope (δ13C) values (−2.8‰ to +3.1‰) throughout the stalagmite's growth reflect a persistently low input of biogenic CO2, indicating that the steep, barren and alpine-like recharge area of today has been in existence for at least the last ∼380 kyr. During MIS 9, the lowest δ13C values occur well after maximum interglacial conditions, suggesting a lag in the development of post-glacial soils in this high-altitude karst. The stable oxygen isotope (δ18O) trends match the main structural features of the major climate proxy records (SPECMAP, Vostok and Devils Hole), suggesting that the δ18O of CC1 has responded to global-scale climate changes, whilst remarkable similarity exists between CC1 δ18O and regional sea-surface temperature reconstructions from North Atlantic core ODP980 and southwest Pacific marine core MD97-2120 through the most detailed part of the CC1 record, MIS 9–8. The results suggest that CC1 and other stalagmites from the cave have the potential to capture a long record of regional temperature trends, particularly in regards to the relative severity of Pleistocene glacial stages.

本研究针对意大利中西部一处高地洞穴内的石笋（CC1）开展年龄结构与稳定同位素组成分析，以探究该区域对全球气候变化的响应。基于28组通过热电离与多接收器电感耦合等离子体质谱法测定的钍-铀年代数据，本研究限定了该石笋的4个生长阶段，揭示其在海洋同位素阶段（Marine Isotope Stage, MIS）11至3（约38万年至4.3万年）期间存在间歇性沉积过程。该石笋的大部分沉积发生在约38万年至28万年之间，该时段曾因MIS 10冰盛期出现短暂沉积间断。沉积作用于约28万年时突然终止，恰处于MIS 8冰盛期之前。当前该洞穴腔室温度为7.5℃，这些沉积间断的时间均接近冰盛期，指示当时区域处于冰冻环境。整个MIS 7阶段以及MIS 6的大部分时期均无沉积记录，仅在约14.1万~12.5万年和约4.3万年出现两个小型生长阶段。14.1万年时的沉积现象表明，在MIS 6冰量接近峰值的时期，当地气温仍高于0℃。石笋整个生长周期内的稳定碳同位素（δ¹³C）值介于-2.8‰至+3.1‰之间，反映出生物源CO₂的输入量持续偏低，表明现今这片陡峭、荒芜且类阿尔卑斯式的补给区至少在过去约38万年里就已存在。在MIS 9阶段，最低的δ¹³C值出现在最大间冰期条件之后很久，暗示该高海拔岩溶区的冰后土壤发育存在滞后效应。稳定氧同位素（δ¹⁸O）的变化趋势与主流气候代用记录（SPECMAP、沃斯托克冰芯（Vostok）、魔鬼洞（Devils Hole））的核心结构特征高度匹配，表明CC1的δ¹⁸O信号响应了全球尺度的气候变化。在CC1记录最为详尽的时段（MIS 9至8），其δ¹⁸O序列与北大西洋ODP980海洋岩芯、西南太平洋MD97-2120海洋岩芯的区域海表温度重建结果存在显著一致性。本研究结果表明，CC1以及该洞穴内的其他石笋有望获取区域温度变化的长期记录，尤其在更新世冰期阶段相对强度的相关研究中具有重要应用价值。