Holocene evolution and accumulation rates for Rodrigues Fringing Reef in the Southwest Indian Ocean

Rodrigues is located at latitude 19°43' S and longitude 63°25' E in the Southwest Indian Ocean and features the best developed reefs in the Mascarenes. \n\nIn 2001 a field expedition to Rodrigues recovered six drill cores using a portable hydraulic drilling rig. In all, two cores were recovered from the windward margin (cores 10 and 17), with a maximum depth of penetration of 4 m. Four cores were recovered from the leeward margin (8, 14, 15, 18) where the maximum depth penetration attained was 4.2 m. Recovery ranged from 23 to 63 %.\n\nThin sections were made and examined petrographically. Radiocarbon dating was performed on selected corals from the base of each core interpreted to have grown in situ and to be free from intraskeletal contamination.\n\nRadiometric dating suggests that Rodrigues reefs approached sea level between 3.1 ± 0.3 cal kyr BP and 1.3 ± 0.2 cal kyr BP. In fact, the windward margin apparently grew to within 2.5 m of present day sea level by approximately 2.7 ± 0.2 cal kyr BP. The leeward margin approached modern day sea level more recently between 1.3 ± 0.2 cal kyr BP and 2.4 ± 0.3 cal kyr BP. Rates of vertical accretion for the top 4 m of the cores range from 0.46 - 1.96 m / kyr.

罗德里格斯岛（Rodrigues）位于南纬19°43′、东经63°25′的西南印度洋海域，是马斯克林群岛（Mascarenes）中珊瑚礁最为发育的区域。

2001年，针对罗德里格斯岛的野外考察队采用便携式液压钻探钻机（portable hydraulic drilling rig）采集了6个钻孔岩芯。其中2个岩芯取自迎风岸坡（编号10、17），最大钻探进尺达4米；剩余4个岩芯取自背风岸坡（编号8、14、15、18），最大钻探进尺为4.2米。岩芯回收率介于23%至63%之间。

研究人员为岩芯制备岩石薄片并开展岩相学分析，同时选取每个钻孔底部被判定为原位生长且无骨骼内污染的珊瑚样本，进行放射性碳定年。

放射性同位素测年结果表明，罗德里格斯岛珊瑚礁的成礁过程在3.1±0.3 cal kyr BP至1.3±0.2 cal kyr BP期间逐步趋近现今海平面。具体而言，迎风岸坡约在2.7±0.2 cal kyr BP时便已生长至距现代海平面仅2.5米的位置；背风岸坡则在更晚的1.3±0.2 cal kyr BP至2.4±0.3 cal kyr BP期间接近现代海平面。钻孔顶部4米层位的垂直加积速率介于0.46~1.96米/千年之间。