Palaeoenvironmental evolution of Cenote Aktun Ha (Carwash) on the Yucatan Peninsula, Mexico and its response to Holocene sea-level rise
Palaeoenvironmental evolution of Cenote Aktun Ha (Carwash) on the Yucatan Peninsula, Mexico and its response to Holocene sea-level rise
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墨西哥尤卡坦半岛Cenote Aktun Ha（洗车场）古环境演化及其对全新世海平面上升的响应
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发表时间：
2008
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影响因子：
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通讯作者：
P. Beddows
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作者：
Jeremy J. Gabriel;E. Reinhardt;M. Peros;D. E. Davidson;P. J. Hengstum;P. Beddows
在墨西哥尤卡坦半岛的阿克顿哈天然井地下水位4米处获得了一个61厘米的岩心。这个天然井距离加勒比海海岸8.6公里，它的形成和演变在很大程度上受到海平面变化的影响。岩心基底年代为6940 ~ 6740 cal年BP，上覆沉积物在随后的约200年间迅速沉积。花粉记录表明，天然井从以红树（Rhizophora mangle）和蕨类植物（Polypodiaceae）为主的沼泽演变为开放水域系统。这些植被变化受水位和盐度控制，因此是过去海平面的有用指标。在基底，δ13Corg同位素比值受陆生植被（- 29‰VPDB）的影响，而在岩心上部（- 33‰），δ13Corg同位素比值向负值转变，表明受淹没天然井池颗粒物质的影响。虽然大部分岩心几乎没有微化石种群，但岩心上部6cm的微化石组合以幼虫氨温虫和变形虫centrropyxis为主。这些种群表明天然井的开放水域条件和大约6600 cal - year BP的主要环境转变，这与加勒比海盆地的海平面上升有关。这些数据与先前建立的加勒比海海平面曲线吻合得很好。我们对天然井Aktun Ha环境历史的重建有助于阐明该地区的植物和水文历史，并突出了天然井沉积物在研究加勒比海全新世海平面历史中的作用。
A 61-cm core was obtained from 4 m below the water table in Cenote Aktun Ha, on the Yucatan Peninsula, Mexico. The cenote is 8.6 km from the Caribbean coast and its formation and evolution have been largely affected by sea-level change. The base of the core dates to 6,940–6,740 cal year BP and overlying sediments were deposited rapidly over the subsequent ~200 years. The pollen record shows that the cenote evolved from a marsh dominated by red mangrove (Rhizophora mangle) and fern (Polypodiaceae) to an open-water system. These vegetation changes were controlled by water level and salinity and are thus useful indicators of past sea level. At the base, the δ13Corg isotopic ratios reveal the influence of terrestrial vegetation (−29‰ VPDB), but shift to more negative values up-core (−33‰), indicating an influence from particulate matter in the flooded cenote pool. Although microfossil populations were nearly absent through most of the core, the microfossil assemblage in the upper 6 cm of the core is dominated by the juvenile foraminifer Ammonia tepida and the thecamoebian genus Centropyxis. These populations indicate open-water conditions in the cenote and a major environmental shift around 6,600 cal year BP, which is related to sea-level rise in the Caribbean basin. These data fit well with previously established sea-level curves for the Caribbean Sea. Our reconstruction of the environmental history of Cenote Aktun Ha helps elucidate the floral and hydrological history of the region, and highlights the utility of cenote sediments for studying the Holocene sea-level history of the Caribbean Sea.