使用Mg同位素来限制多洛米特的形成温度
Xi Li1, Guangyou Zhu2, Yifei Ai3
1School of Geosciences, Yangtze University, Wuhan, 430100, China. geolixi@126.com.
Scientific reports
|March 29, 2025
概括
同位素为确定多洛米特形成温度提供了可靠的方法,解决了沉积物学中长期存在的挑战. 这项研究成功地使用Mg同位素来计算塔林盆地的各种多洛米特类型的温度.
科学领域:
- 地质化学 地质化学
- 沉积物学的沉积物学
- 同位素地球化学 同位素地球化学
背景情况:
- "多洛米特问题"突出了确定多洛米特形成温度的困难,这是沉积物学中的关键参数.
- (Mg) 的同位素在多洛米特中稳定,并随着温度的预测而分化,使其成为一个有前途的地热仪.
- 以前用于确定多洛米特形成温度的方法存在局限性,并且经常受到争议.
研究的目的:
- 评估Mg同位素 (δ26Mg) 作为多洛米特形成的可靠温度计的潜力.
- 用Mg同位素计算Tarim盆地Ediacaran到奥尔多维纪的多洛米特形成温度的样本.
- 为了比较Mg同位素衍生的温度与现有的流体含量和凝聚同位素的数据.
主要方法:
- 在塔里姆盆地的各种多洛米特样本中分析Mg同位素组成 (δ26Mg).
- 应用已建立的Mg同位素温度平衡分离方程 (Δ26Mgdol-fluid和Δ26Mgdol-cal).
- 计算不同的多洛米特晶体大小 (D1,D2,D3) 的形成温度.
主要成果:
- 在多洛米特类型中,Mg值有所不同:D1 (-1.98~-1.69‰),D2 (-1.68~-1.33‰) 和D3 (-2.35~-1.99‰).
- 计算的形成温度:D1 (45.065.4°C),D2 (53.173.9°C) 和D3 (142.4189.0°C). 它们的温度是:
- 同位素温度估计显示,与之前的研究中的液体含量和聚集的同位素数据有很强的一致性.
结论:
- 同位素为确定多洛米特形成温度提供了强大而创新的方法.
- 这些发现有助于解决沉积物学中长期存在的"多洛米特问题".
- 这项研究验证了Mg同位素作为可靠的地热仪用于二氧化碳酸盐环境的使用.
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