Lacustrine sediments from two setions in northern Greece

We investigated two lignite quarries in northern Greece for orbital and suborbital climate variability. Sections Lava and Vegora are located at the southern and northern boundaries of the Ptolemais Basin, a northwest southeast elongated intramontane basin that contains Upper Miocene to Lower Pliocene lacustrine sediments. Sediments show cyclic alterations of marl-rich (light), and coal-rich or clay-rich (dark) strata on a decimeter to meter scale. First, we established low-resolution ground-truth stratigraphy based on paleomagnetics and biostratigraphy. Accordingly, the lower 67 m and 65 m that were investigated in both sections Vegora and Lava, respectively, belong to the Upper Miocene and cover a time period of 6.85 to 6.57 and 6.46 to 5.98 Ma at sedimentation rates of roughly 14 and 22 cm/ka. In order to obtain a robust and high-resolution chronology, we then tuned carbonate minima (low L* values; high magnetic susceptibility values) to insolation minima. […]

我们对希腊北部的两个褐煤采石场开展了轨道与亚轨道气候变异性（orbital and suborbital climate variability）研究。Lava剖面与Vegora剖面分别位于托勒密盆地（Ptolemais Basin）的南缘与北缘——该盆地为西北-东南走向的山间盆地（intramontane basin），赋存上中新世至下上新世湖相沉积物（lacustrine sediments）。沉积物呈现分米至米级尺度上富泥灰岩（浅色）与富煤或富粘土（深色）地层的周期性交替（cyclic alterations）。首先，我们基于古地磁学（paleomagnetics）与生物地层学（biostratigraphy）建立了低分辨率基准地层序列。据此，Vegora剖面与Lava剖面中所研究的下部67米与65米地层均属于上中新世，对应的时间范围分别为6.85至6.57 Ma及6.46至5.98 Ma，沉积速率（sedimentation rates）约为14 cm/ka与22 cm/ka。为获取稳健的高分辨率年代学（chronology），我们进一步将碳酸盐最小值（低L*值；高磁化率（magnetic susceptibility）值）与日照最小值（insolation minima）进行调谐。[…]