Molecular paleothermometry of the early Toarcian climate perturbation
Molecular paleothermometry of the early Toarcian climate perturbation
复制标题
DOI：
10.1016/j.gloplacha.2020.103351
复制
发表时间：
2020-10
影响因子：
3.9
通讯作者：
W. Ruebsam;M. Reolid;N. Sabatino;D. Masetti;L. Schwark
中科院分区：
文献类型：
--
作者：
W. Ruebsam;M. Reolid;N. Sabatino;D. Masetti;L. Schwark
本文利用分子古温度计，基于古生物脂类的TEX 86代用指标，重建了特提斯大陆架西北部Pliensbachian晚期至Toarcian早期（早侏罗世，~183 Ma）的绝对海表温度（SST）。我们对西班牙和意大利露头的综合记录显示，在大约300万年的时间段内，热带SST在22 ° C和32 °C之间变化，包括5-10 °C量级的瞬时温度漂移，直减率为大约0.1 °C/kyr。重建SST的变化与海平面波动和海洋生物钙化物的δ 18 O同位素特征共变，记录了冰室和温室状态之间的经常性变化。重建的SST和大气CO2 δ 13 C同位素的平行趋势可能反映了同位素轻碳在冰室阶段储存在冰冻圈水库和温室阶段释放。不稳定冰冻圈的存在被认为是解释推断的快速气候波动的先决条件，并作为一个水库，以促进明显的碳同位素偏移。
In this paper, we use molecular paleothermometry, based on the TEX86proxy derived from fossilized archaeal lipids, to reconstruct absolute sea surface temperatures (SSTs) for the northwest Tethys Shelf during the late Pliensbachian to early Toarcian (Early Jurassic, ~183 Ma) stages. Our composite record from outcrops in Spain and Italy reveals that tropical SSTs varied between 22 and 32 °C over a ~ 3 Myr time period, including transient temperature excursions of 5–10 °C magnitude with lapse rates of ~0.1 °C/kyr. Changes in reconstructed SSTs covaried with sea level fluctuations and δ18O isotope signatures of marine biocalcifiers, recording recurrent shifts between icehouse and greenhouse states. Parallel trends of reconstructed SST and δ13C isotopes of atmospheric CO2may reflect storage of isotopically light carbon in cryosphere reservoirs during icehouse phases and release during greenhouse phases. The existence of a labile cryosphere is considered a prerequisite to explain the inferred rapid climate fluctuations and as a reservoir to facilitate pronounced carbon isotope excursions.