相关实验视频
Updated: Jul 19, 2025

06:00
Determination of the Settling Rate of Clay/Cyanobacterial Floccules
Published on: June 11, 2018
7.0K
增强的粘土形成是维持中世气候最佳状态的关键
Alexander J Krause1, Appy Sluijs2, Robin van der Ploeg2,3
1University College London, Earth Sciences, London, UK.
概括
中欧纪的气候最佳期.
科学领域:
- 古气候学 古气候学
- 地质化学 地质化学
- 碳循环研究 碳循环研究
背景情况:
- 中世气候最佳期 (MECO) 是一个长期的全球变暖事件 (约4000万年前),其特点是二氧化碳增加和海洋酸化.
- 该MECO的延长持续时间令人困惑,因为酸盐气候应作为减少CO2的负反.
- 了解酸盐气候变化的动态对于解释长期气候事件至关重要.
研究的目的:
- 为了研究中世气候最佳时期的酸盐气候变化过程.
- 了解维持这种长期变暖事件的机制.
- 探索粘土矿物质形成在中纪碳循环中的作用.
主要方法:
- 在碳酸盐丰富的深海沉积物中分析同位素比率 (δ7Li),作为酸盐气候变化的标志物.
- 使用盒式模型来模拟气候变化过程和碳循环反.
- 将同位素数据与已知的气候和地质事件进行比较.
主要成果:
- 检测到一个显著的阳性 δ7Li外流 (~3‰),在已识别的变暖事件中是独一无二的.
- 盒子模型模拟表明从一致到不一致的酸盐气候变化的转变.
- 有证据表明,粘土矿物质形成的增加隔离了子,扰乱了碳酸盐-酸盐循环.
结论:
- MECO的持续变暖是由气候变化过程的转变驱动的,有利于粘土形成而不是离子释放.
- 大陆火山活动的增加引发了变暖,但粘土矿物质的动态延长了它.
- 粘土矿物质形成是中等时间尺度 (100,000年) 气候事件和碳循环的关键因素.
相关概念视频
Global Climate Change
24.5K
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.
24.5K
Diversity of Archaea III
32
Crenarchaeota, a prominent phylum of Archaea, is remarkable for its ability to thrive in extreme environments characterized by high temperatures and acidity. These microorganisms inhabit sulfuric hot springs, volcanic systems, and submarine hydrothermal vents, where temperatures often exceed 100°C. The unique adaptations of Crenarchaeota not only allow survival under such extreme conditions but also provide insights into the mechanisms of life in primordial Earth-like...
32
The Fossil Record
25.3K
The fossil record documents only a small fraction of all organisms that have ever inhabited Earth. Fossilization is a rare process, and most organisms never become fossils. Moreover, the fossil record only exhibits fossils that have been discovered. Nevertheless, sedimentary rock fossils of long-lived, abundant, hard-bodied organisms dominate the fossil record. These fossils offer valuable information, such as an organism's physical form, behavior, and age. Studying the fossil record helps...
25.3K
Porosity in Cement Paste
173
The porosity of concrete is a measure of the void spaces within its structure. These spaces impact its strength and durability significantly. When water and cement interact, a chemical reaction called hydration creates a semi-solid paste. This paste includes combined water, making up approximately 23% of the cement's dry mass, and gel water, which fills minuscule voids known as gel pores, accounting for about 28% of the cement gel volume.
The balance of water to cement in the mix is...
The balance of water to cement in the mix is...
173
Isothermal Processes
3.7K
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...
3.7K
Transition Zone
115
The transition zone in concrete is a critical area where aggregate meets cement paste, marked by a distinct porosity and weakness compared to the surrounding material. The adhesion around the aggregates is primarily due to Van Der Waals forces. The voids within this zone influence its robustness; initially, it is less durable than the surrounding bulk mortar due to larger voids. Initially, when concrete is compacted, a higher water-cement ratio near the aggregates leads to the formation of...
115

