Interannual-to millennial-scale climate cycles have been recognized in ancient sedimentary strata and may be closely associated with solar activity. However, the physical driving mechanisms of such cycles remain a mystery. To better understand the nature and evolution of suborbital cycles in ice-free conditions, we performed a quantitative analysis of high-resolution phosphorus (P), gray-scale values, and iron (Fe) data obtained from a core deposited in a mid-latitude lake (Funing Formation of the Subei Basin) during the Late Paleocene-Early Eocene. Time series analysis reveals evidence for ∼88-yr and ∼ 11-yr solar activity cycles in the gray value data, and ∼ 20-kyr precession cycles, ∼10-kyr half-precession cycles, and ∼ 2-kyr solar activity cycles in the Fe data. The data indicate that paleoclimate changes in the Subei Basin at this time were driven by both orbital and suborbital cycles. Amplitude modulation analysis suggests that ∼20-kyr precession modulated the amplitude of the observed 2-kyr cycles. It is inferred that the Earth's climate is driven not only by eccentricity-modulated precession cycle, but also by precession-modulated millennial cycles.

中文翻译：

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苏北盆地晚古新世-早始新世陆地地层记录的轨道和亚轨道气候周期


年际至千年尺度的气候循环已在古代沉积地层中得到认可，并且可能与太阳活动密切相关。然而，这种循环的物理驱动机制仍然是个谜。为了更好地了解无冰条件下亚轨道循环的性质和演化，我们对从沉积在中层的核心获得的高分辨率磷（P）、灰度值和铁（Fe）数据进行了定量分析。晚古新世-早始新世的纬度湖（苏北盆地阜宁组）。时间序列分析揭示了灰度值数据中~88年和~11年太阳活动周期的证据，以及~20-kyr进动周期、~10-kyr半进动周期和~2-kyr太阳活动周期的证据。 Fe 数据。数据表明，此时苏北盆地的古气候变化是由轨道和亚轨道循环共同驱动的。振幅调制分析表明~20-kyr进动调制了观测到的2-kyr周期的振幅。据推测，地球气候不仅受偏心率调制的进动周期驱动，而且还受进动调制的千年周期驱动。