Seasonal and subseasonal climate changes recorded in laminated diatom ooze sediments, Adélie Land, East Antarctica
Seasonal and subseasonal climate changes recorded in laminated diatom ooze sediments, Adélie Land, East Antarctica
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东南极洲阿德利地层状硅藻泥沉积物记录的季节性和次季节气候变化
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发表时间：
2006
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通讯作者：
Virginie Mas
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作者：
D. Denis;X. Crosta;S. Zaragosi;Oscar E Romero;Bernard Martin;Virginie Mas
在MD 130-Images X-CADO巡航期间，从东南极洲阿德利地附近的Dumont d 'Urville槽中检索了一个40米长的沉积物岩心，覆盖了1000-9600年的BP时期。这一沉积序列允许记录全新世气候季节性变化。在这里，我们展示了硅藻群落，岩屑颗粒分布和钛含量测量的两个30厘米长的薄切片序列的初步结果。这两个层序起源于两种不同的气候体制，即较冷的新冰期和较暖的高温期。在微尺度分辨率下测量了Neoglacial的25个叠层和Hypsithermal的14个叠层的代理。这两个序列显示交替的浅绿色和深绿色纹层。光纹层低陆源输入和高海冰边缘硅藻通量的结果，并解释为代表春季。深色纹层的结果，从高陆源输入与多样化的开放海洋硅藻植物群混合，并解释为代表的夏秋季节。因此，这两个序列解决了一年的对联组成的一个光明加一个黑暗的叶片。与硅藻组合的变化，在每个序列和两个序列之间的相对厚度的叠层和每年的对联，观察到的变化，提供信息的年际到千年的环境条件的变化。
A 40 m long sediment core covering the 1000–9600 years BP period was retrieved from the Dumont d'Urville Trough off Adélie Land, East Antarctica, during the MD 130–Images X-CADO cruise. This sedimentary sequence allows the documentation of changes in climate seasonality during the Holocene. Here we show preliminary results of diatom communities, lithic grain distribution and titanium content measured on two 30 cm long sequences of thin sections. The two sequences originate from two different climate regimes, the colder Neoglacial and the warmer Hypsithermal. Proxies were measured at microscale resolution on 25 laminations for the Neoglacial and 14 laminations for the Hypsithermal. The two sequences reveal alternating light-green and dark-green laminae. Light laminae result from low terrigenous input and high sea-ice edge diatom fluxes and are interpreted to represent the spring season. Dark laminae result from high terrigenous input mixed with a diversified open ocean diatom flora and are interpreted to represent the summer–autumn season. The two sequences therefore resolve annual couplets composed of one light plus one dark lamina. Variations in the relative thickness of laminations and annual couplets, associated with diatom assemblage changes, are observed in each sequence and between the two sequences giving information on interannual to millennial changes in environmental conditions.