在北美中部的伊欧纪-奥利古纪过渡期,气温大幅下降
Alessandro Zanazzi1, Matthew J Kohn, Bruce J MacFadden
1Department of Geological Sciences, University of South Carolina, Columbia, South Carolina 29208, USA. azanazzi@geol.sc.edu
Nature
|February 9, 2007
概括
世 - 世过渡期在40万年内出现了相当大的大陆冷却8.2°C,影响了爬行动物和两动物,但没有影响哺乳动物. 这种气候变化很可能是由大气中的二氧化碳减少所驱动的.
科学领域:
- 古气候学 古气候学
- 古生物学的古生物学
- 地质化学 地质化学
背景情况:
- 世 - 世过渡期 (大约. 3350万年前) 标志着一个主要的代冷却事件.
- 海洋气候记录得到了很好的研究,但大陆变化仍然不太了解.
- 以前的研究产生了关于大陆气候变化的时间和规模的不一致的数据.
相关概念视频
What is Climate?
17.5K
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.
17.5K
Global Climate Change
24.4K
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.
24.4K
Effects of Temperature on Free Energy
21.8K
The spontaneity of a process depends upon the temperature of the system. Phase transitions, for example, will proceed spontaneously in one direction or the other depending upon the temperature of the substance in question. Likewise, some chemical reactions can also exhibit temperature-dependent spontaneities. To illustrate this concept, the equation relating free energy change to the enthalpy and entropy changes for the process is considered:
21.8K
Decreased Body Temperature
1.2K
A decreased body temperature can occur in patients with hypothermia and frostbite. Heat loss with extended cold exposure overpowers the body's ability to create heat, resulting in hypothermia. Core temperature readings help classify hypothermia. Mild hypothermia is temperatures between 32 °C (89.6 °F) and 35°C (95 °F) and is caused by impaired thermoregulation. Moderate hypothermia is temperatures between 28 C (82.4 °F) and 32 °C (89.6 °F) caused by...
1.2K
Isothermal Processes
3.8K
A thermodynamic process that occurs at constant temperature is called an isothermal process. Heat slowly flows into the system or out of the system to maintain thermal equilibrium. Processes involving phase changes like water evaporation into steam or freezing water into ice at a constant temperature are examples of Isothermal Processes.
An ideal gas can also undergo isothermal expansion or compression.
For example, consider 1 mole of an ideal gas inside an isolated cylinder at initial volume V...
An ideal gas can also undergo isothermal expansion or compression.
For example, consider 1 mole of an ideal gas inside an isolated cylinder at initial volume V...
3.8K
Temperature Dependent Deformation
743
In a nonhomogeneous rod made up of steel and brass, restrained at both ends and subjected to a temperature change, several steps are involved in calculating the stress and compressive load. Due to the problem's static indeterminacy, one end support is disconnected, allowing the rod to experience the temperature change freely. Next, an unknown force is applied at the free end, triggering deformations in the rod's steel and brass portions. These deformations are then calculated and added...
743


