约7亿年前“雪球地球”海洋有多冷？最新研究首次揭示约-15℃

Core Insights - The research led by Chinese scientists provides the first quantitative evidence of ocean temperatures during the "Snowball Earth" period, revealing that local ocean temperatures could have dropped to approximately -15°C, with salinity levels significantly higher than modern seawater [1][3][4] Group 1: Research Findings - The study utilized iron isotopes as a "paleothermometer" to directly quantify ocean temperatures from around 700 million years ago during the "Snowball Earth" ice age [1][3] - The research indicates that the ocean during this period was much colder than previously estimated, with temperatures around -15±7°C, which is nearly 20°C lower than the coldest modern deep-sea temperatures [4] - The extreme cold was attributed to high salinity levels in the ocean, which lowered the freezing point to about -11°C, preventing complete freezing of the seawater [4] Group 2: Historical Context - The "Snowball Earth" period, occurring approximately 720 to 635 million years ago, was characterized by global glaciation, where ice covered the entire planet from poles to equator [3] - This research provides insights into the potential existence of unique microenvironments during extreme climatic conditions, which may offer clues about early life survival mechanisms [3]