从古世末期到伊世早期的天文步伐,全球变暖事件的天文步伐
Lucas J Lourens1, Appy Sluijs, Dick Kroon
1Faculty of Geosciences, Department of Earth Sciences, and.
Nature
|June 10, 2005
概括
研究人员发现了第二个全球变暖事件,埃尔莫地平线,大约在古世 - 世热量最大后200万年. 这一事件与天文周期有关,为地球气候历史提供了新的见解.
科学领域:
- 古气候学 古气候学
- 地质化学 地质化学
- 海洋地质学海洋地质学
背景情况:
- 古世 - 世热极值 (PETM) 是5500万年前极端全球变暖的时期.
- 假设PETM是由海洋酸盐释放的甲引起的,导致碳同位素游览和沉积物溶解.
- 潜在的PETM触发因素包括火山活动,彗星撞击或海洋电流变化.
研究的目的:
- 为了研究一个独特的碳酸盐贫困的红色粘土层,埃尔莫地平线,在深海核心中发现.
- 确定埃尔莫地平线的时间和性质及其与已知的气候事件的关系.
- 为了探索过去全球变暖事件的潜在天文节奏.
主要方法:
- 来自沃尔维斯山脊的深海核心样本的分析.
- 轨道调整以准确地确定埃尔莫地平线沉积的日期.
- 沉积层的地球化学和生物学分析.
- 埃尔莫地平线与来自其他海洋盆地的碳同位素数据的相关性.
主要成果:
- 确定了埃尔莫地平线,这是一个碳酸盐贫乏的红色粘土层,可追溯到PETM后约200万年.
- 埃尔莫地平线表现出与PETM相似的地化学和生物特征,但规模较小.
- 其他海洋盆地的巧合碳同位素耗尽表明,埃尔莫地平线代表了第二个全球热最大值.
- 无论是PETM还是Elmo地平线事件,都与405kyr和100kyr离心率周期中的最大值相关.
结论:
- 埃尔莫地平线代表了PETM之后的显著,尽管较小的全球变暖事件.
- 地球的气候系统可能经历了多次,天文节奏的变暖事件.
- 轨道偏心周期似乎是这些主要的代热事件的关键因素.
相关概念视频
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Overview
01:16What is Climate?
Climate refers to the prevailing weather conditions in a specific area over an extended period. As the saying goes, “Climate is what you expect. Weather is what you get.” Climate is influenced by geographic factors, such as latitude, terrain, and proximity to bodies of water.
01:50Global Climate Change
Throughout its ~4.5 billion year history, the Earth has experienced periods of warming and cooling. However, the current drastic increase in global temperatures is well outside of the Earth’s cyclic norms, and evidence for human-caused global climate change is compelling. Paleoclimatology, the study of ancient climate conditions, provides ample evidence for human-caused global climate change by comparing recent conditions with those in the past.
02:06Conditions on Early Earth
Around 4 billion years ago, oceans began to condense on earth while volcanic eruptions released nitrogen, carbon dioxide, methane, ammonia, and hydrogen into the primordial atmosphere. However, organisms with the characteristics of life were not initially present on earth. Scientists have used experimentation to determine how organisms evolved that could grow, reproduce, and maintain an internal environment.
02:06Conditions on Early Earth
Around 4 billion years ago, oceans began to condense on earth while volcanic eruptions released nitrogen, carbon dioxide, methane, ammonia, and hydrogen into the primordial atmosphere. However, organisms with the characteristics of life were not initially present on earth. Scientists have used experimentation to determine how organisms evolved that could grow, reproduce, and maintain an internal environment.
01:17Radiation: Applications
The average temperature of Earth is the subject of much current discussion. Earth is in radiative contact with both the Sun and dark space; it receives almost all its energy from the radiation of the Sun and reflects some of it into outer space. Dark space is very cold, about 3 K, so Earth radiates energy into it. For instance, heat transfer occurs from soil and grasses, the rate of which can be so rapid that frost can occur on clear summer evenings, even in warm latitudes.
The average...
The average...