Paleogene orbitally calibrated climate cycles

古近纪轨道校准气候周期

• 批准号: NE/D000343/1
• 负责人: Heiko Pälike
• 金额: $ 4.6万
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2006
• 资助国家: 英国
• 起止时间: 2006 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FD000343%2F1
• 关键词: Paleogene; orbitally; calibrated; climate; cycles

Just as tree rings can be used to count astronomical years back into the past and ancient coral growth rings can be used to estimate the number of days per year in the past, layers of undisturbed sedimentary rocks can potentially record cyclical variations in the orbital configuration of Earth and other planets. These astronomical variations affect the amount of sunshine received at the top of the atmosphere, filtered through the climate system (e.g. ice ages), which finally influences the amount and type of sediment deposited in, e.g., the deep sea. Changes of these astronomical parameters: the Earth's eccentricity, obliquity (tilt), and climatic precession (wobble of the spin axis), occur on time scales of thousands to hundreds of thousands of years. The necessary geological records from the deep sea have only recently become available through the international Ocean Drilling Program, which recovers sediment cores from hundreds of metres below the sea bed in waters several miles deep. Previous work has already exploited the various opportunities that arise from having a built-in 'metronome' in the rock record, and particularly if these same sediment layers contain additional information about, for example, the direction of the Earth's magnetic field, magnetic lineations on the sea-floor that tell us how quickly, for example, North America and Eurasia are drifting apart, and most importantly, climate indicators that can be more accurately dated, and thus give information on how fast climatic change can occur, and with what response of the Earth system to an applied forcing or perturbation. Such research has essentially been proceeded from the present into the past, and very good records were just recently published back to the Eocene/Oligocene geological boundary ca. 34 million years ago. Our medium term aim is to extend these calibrations and climate records at high resolution back to the age when the dinosaurs went extinct, ca. 65 million years ago, also known as the Cenozoic. To achieve this goal, for a time period when crocodiles were known to live within the Arctic circle, and the world was in a warmer, 'green-house' state, we want to analyse the chemical composition of fossilised marine fossils the size of a pin-head ('foraminifera') to gain information about climate cycles, the temperature at certain locations in the world's oceans, and the amount of water that was trapped as ice in glaciers and around the Earth's poles, particularly Antarctica. By analysing carbon atoms in carbonate fossil shells, we also investigate the evolution of carbon dioxide consumers and producers, which have been known to respond to climate cycles. To extend the 'astronomical clock' of the rock record back in time, to around two thirds of our longer term goal, we have obtained new samples through drilling into the sea-floor, in order to recover undisturbed sediments that are deposited at a rate of around 1 to 2 cm per thousand years.

就像树木的年轮可以用来计算天文年回到过去，古代珊瑚的年轮可以用来估计过去每年的天数，未受干扰的沉积岩层可以记录地球和其他行星轨道结构的周期性变化。这些天文变化影响了大气层顶部接收到的阳光量，通过气候系统（例如冰河时代）过滤，最终影响沉积物的数量和类型，深海这些天文参数的变化：地球的偏心率，倾斜度（倾斜）和气候岁差（自转轴的摆动），发生在数千到数十万年的时间尺度上。直到最近才通过国际大洋钻探计划获得必要的深海地质记录，该计划从几英里深的沃茨海床以下数百米处采集沉积物岩心。以前的工作已经利用了岩石记录中内置的“节拍器”所带来的各种机会，特别是如果这些相同的沉积层包含额外的信息，例如，地球磁场的方向，海底的磁性线理告诉我们，例如，北美和欧亚大陆正在漂移分开，最重要的是，可以更准确地确定日期的气候指标，从而提供有关气候变化发生速度的信息，以及地球系统对施加的强迫或扰动的反应。这样的研究基本上是从现在到过去进行的，最近发表了非常好的记录，可以追溯到始新世/渐新世地质边界。三千四百万年前。我们的中期目标是将这些校准和高分辨率的气候记录扩展到恐龙灭绝的时代，大约是1980年。6500万年前，也被称为新生代。为了实现这一目标，在鳄鱼生活在北极圈内的一段时间里，世界处于温暖的“温室”状态，我们想分析针头大小的化石的化学成分（有孔虫）来获得有关气候循环的信息，世界海洋某些地方的温度，以及被冰川和地球两极（特别是南极洲）的冰所困的水量。通过分析碳酸盐化石壳中的碳原子，我们还研究了二氧化碳消费者和生产者的演变，这些消费者和生产者对气候周期做出了反应。为了将岩石记录的“天文钟”时间回溯到我们长期目标的三分之二左右，我们通过钻探海底获得了新的样本，以恢复以每千年1至2厘米的速度沉积的未受干扰的沉积物。

项目成果

Cyclicity in the middle Eocene central Arctic Ocean sediment record: Orbital forcing and environmental response

始新世中期北冰洋中部沉积物记录的周期性：轨道强迫和环境响应

• DOI: 10.1029/2007pa001487
• 发表时间: 2008
• 期刊: Paleoceanography
• 作者: Sangiorgi F

Rock clock synchronization

• DOI: 10.1038/ngeo197
• 发表时间: 2008-05
• 期刊: Nature Geoscience
• 影响因子: 18.3
• 作者: H. Pälike;F. Hilgen

Orbital scale variations and timescales from the Arctic Ocean

北冰洋的轨道尺度变化和时间尺度

• DOI: 10.1029/2007pa001490
• 发表时间: 2008
• 期刊: Paleoceanography
• 作者: Pälike H

Age model and core-seismic integration for the Cenozoic Arctic Coring Expedition sediments from the Lomonosov Ridge

• DOI: 10.1029/2007pa001476
• 发表时间: 2008-03-13
• 期刊: PALEOCEANOGRAPHY
• 作者: Backman, Jan;Jakobsson, Martin;Heil, Chip
• 通讯作者: Heil, Chip

Antarctic ice sheet and oceanographic response to eccentricity forcing during the early Miocene

• DOI: 10.5194/cp-7-869-2011
• 发表时间: 2011-01-01
• 期刊: CLIMATE OF THE PAST
• 影响因子: 4.3
• 作者: Liebrand, D.;Lourens, L. J.;Paelike, H.
• 通讯作者: Paelike, H.