Late Quaternary palaeosol records from subtropical (38°S) to tropical (16°S) South America and palaeoclimatic implications
Late Quaternary palaeosol records from subtropical (38°S) to tropical (16°S) South America and palaeoclimatic implications
复制标题
南美洲亚热带（南纬38°）至热带（南纬16°）晚第四纪古土壤记录及其古气候意义
DOI：
10.1016/j.quaint.2008.01.005
复制
发表时间：
2008
影响因子：
2.2
通讯作者：
Glaser B
中科院分区：
文献类型：
--
作者：
Zech W;Zech M;Peinemann N;Morras H;Moretti L;Ogle N;Kalim RM;Fuchs M;Schad P;Glaser B
南美洲亚热带低地(∼23-38°S)的黄土和古土壤具有很大的潜力，可以作为晚第四纪环境与气候变化的档案。目前，年平均降水量总体上是从N到S、从E到W递减的，但季节变化较为复杂，南半球夏季降水与季风环流有关，南半球冬季降水与东南向贸易有关。本文介绍了S-N样带三个具有代表性的风成/冲积土壤剖面的多代理地球化学分析结果，这些剖面旨在重建过去的气候变化：(I)亚热带南缘的“Chasico”剖面(38°S)，(Ii)亚热带北缘Misiones的“D4”剖面(27°S)，以及(Iii)玻利维亚低地大草原的“拉古纳-苏夸拉”剖面(16°S)。我们的结果表明，在∼16kaBP之前，条件可能非常寒冷和干燥。除“D4”外，由于相当稀少的植被覆盖和随之而来的通货紧缩，黄土或土壤没有得到保护。在“Chasico”，沙子的堆积(直接覆盖在第三纪)只在冰川晚期开始，这表明气温上升和季风降水增加(与高原上的“Tauca”湿润阶段重合)。在“D4”中，古土壤保存在晚冰川沉积和通货紧缩间歇期的下方。这个古土壤的年代是∼40kaBP，记录了一个更早的、但强度较小(向南到达)的季风降水阶段(高原上的印加华斯)。尽管冰川晚期的季节性似乎非常明显，但在全新世早期，“Chasico”和“D4”的有机质生产和保存条件变得更加有利。我们认为，热带外冬季降水起到了比以前和现在更重要的作用。在∼7.5kaBP和3kaBP之间，C4植物沿S-N样带的扩展表明干旱加剧，这可能是由于热带外环流的减弱和相对较弱的季风环流所致。仅在∼3kaBP之后，由于季风的重新加强，气候再次变得更加湿润。
Loess and palaeosols in the subtropical lowlands of South America (∼23–38°S) have a large potential to serve as archives of Late Quaternary environmental and climate changes. At present, mean annual precipitation generally decreases from N to S and from E to W, though with a complex seasonal pattern with austral summer rainfall related to the monsoonal circulation and with austral winter rainfall related to the SE-trades. In this paper, we present results of multiproxy geochemical analyses from three representative eolian/alluvial soil profiles along a S–N transect aiming at the reconstruction of past climate changes: (i) profile “Chasico” at the southern border of the subtropics (38°S), (ii) “D4” in Misiones at the northern border of the subtropics (27°S), and, for comparison, (iii) “Laguna Sucuara” in the savannas of the Bolivian lowlands (16°S). Our results show that before ∼16kaBP, conditions were likely very cold and dry. Except for in “D4”, loess or soils are not preserved due to rather scarce vegetation cover and resultant deflation. In “Chasico”, accumulation of sands (directly overlying the Tertiary) starts only during the Late Glacial, indicating increasing temperatures and increased monsoonal precipitation (coinciding with the “Tauca” wet phase on the Altiplano). In “D4”, a palaeosol is preserved below the Late Glacial sediments and the deflation hiatus. This palaeosol is dated to ∼40kaBP and documents an earlier, but less intensive (southward reaching) phase of monsoonal precipitation (“Inca Huasi” on the Altiplano). Whereas the seasonality during the Late Glacial seems to have been very pronounced, conditions for organic matter production and preservation became much more favourable at “Chasico” and “D4” during the Early Holocene. We suggest that extra-tropical winter precipitation played a more important role than before and than today. Between ∼7.5 and 3kaBP, the expansion of C4 plants along the S–N transect suggests increasing aridity, probably due to a weakening of the extra-tropical circulation in combination with a relatively weak monsoonal circulation. Only after ∼3kaBP climate became more humid again due to the re-strengthening of the monsoon.
登录
查看更多内容
影响因子：
4
作者：
M. Fuchs;G. Wagner
通讯作者：
M. Fuchs;G. Wagner
苯硼酸修饰水凝胶亲和芯片在糖化蛋白高通量质谱分析中的应用。
影响因子：
2
作者：
S. Gontarev;V. Shmanai;Simone K. Frey;M. Kvach;F. Schweigert
通讯作者：
F. Schweigert
DOI：
--
发表时间：
2001
期刊：
影响因子：
--
作者：
M. V. Bianchinotti;M. Quattrocchio;C. Borel
通讯作者：
C. Borel
阿根廷潘帕斯东北部自 14 世纪以来 11,000 年以来的环境历史，来自卢汉河的冲积序列
影响因子：
2.3
作者：
A. Prieto;Adriana M. Blasi;Claudio G. De Francesco;C. Fernández
通讯作者：
C. Fernández
阿根廷东部草原晚冰期-全新世过渡的植被历史。
DOI：
--
发表时间：
2000
期刊：
影响因子：
--
作者：
A. Prieto
通讯作者：
A. Prieto