Paleomagnetic chronostratigraphy of Holocene Laguna Minucúa, Oaxaca, Mexico
Paleomagnetic chronostratigraphy of Holocene Laguna Minucúa, Oaxaca, Mexico
复制标题
DOI：
10.1016/j.quaint.2016.06.038
复制
发表时间：
2016-08
影响因子：
2.2
通讯作者：
S. Lund;M. Goman;Arthur A. Joyce
中科院分区：
文献类型：
--
作者：
S. Lund;M. Goman;Arthur A. Joyce
从墨西哥瓦哈卡州拉古纳米努阿的两个岩心(MN1、MN2)恢复了全矢量古地磁长期变化(PSV)记录。拉古纳-米努阿湖的沉积物是层状的，可能是不同的，直到沉积物/水界面15厘米以内。它们可能成为墨西哥南部重要的古气候记录。然而，放射性碳测年在估计湖泊沉积物的年龄方面一直含糊其辞(Goman等人，2013年)。MN1和MN2岩心的PSV记录在它们之间是可对比的，并且具有独特的变化模式，可以与来自美国西部的良好年代的PSV记录相关联。PSV关联确定了最长的核心(Mn2)向后延伸到∼4500卡的BP。假设MN2板是Varive，它们的平均厚度(1.2%mm)和岩芯长度提供了一个独立的估计∼4600千卡BP，没有明显的差异。其中一个放射性碳测年的年龄为1120±60千卡BP，其对应的古地磁年龄为1140±50千卡BP，同样也没有显著差异。因此，我们的估计是，拉古纳-米努阿沉积是多样化的，代表了过去4500年来墨西哥南部非凡的、高分辨率的古气候信息储存库。
Full-vector paleomagnetic secular variation (PSV) records have been recovered from two cores (MN1, MN2) collected from Laguna Minucúa, Oaxaca, Mexico. The sediments of Laguna Minucúa are laminated, probably varved, to within 15 cm of the sediment/water interface. They may become a key paleoclimate record for Southern Mexico. However, radiocarbon dating has been equivocal at estimating the age of the lake sediments (Goman et al., 2013). The PSV records from cores MN1 and MN2 are correlatable between them and have a distinctive pattern of variability that can be correlated to well-dated PSV records from the western USA. The PSV correlations establish that the longest core (MN2) extends back ∼4500 cal BP. Assuming the MN2 lamina are varves, their average thickness (1.2 mm) and core length provide an independent estimate of ∼4600 cal BP, not significantly different. One radiocarbon date with an age of 1120 ± 60 cal BP, occurs at a depth in core MN2 with an equivalent paleomagnetic age of 1140 ± 50 cal BP, again not significantly different. Therefore, our estimate is that the Laguna Minucúa sediments are varved and represent a remarkable, high-resolution repository of paleoclimate information for Southern Mexico for the last 4500 years.