Scholarlink

<p>The origin and composition of Earth’s silica-rich continental crust, particularly the lower crust, remain uncertain. Stable continental crust, including cratons and crust older than 200 million years, is marked by enrichment of radiogenic heat-producing elements (U, Th and K) in the upper crust and depletion in the lower crust. Because the lower crust probably consists of &gt;50% aluminous metasedimentary and evolved metaigneous rocks—both initially enriched in U and Th—continental differentiation requires a mechanism to transfer these elements upwards. Here, in our analysis of partially melted metasedimentary and metaigneous rocks, we show that ultrahigh temperatures (&gt;900 °C) are essential to stratify heat production and stabilize crust. Removal of small fractions of ultrahigh-temperature melt generated by fluid-absent melting can produce the observed lower-crustal depletions in U and Th. By contrast, lower-temperature melting fails to drive differentiation owing to the resilience of monazite to dissolution in granitic melts. Our findings establish ultrahigh-temperature melting as an important criterion for the formation of stable continents, providing a direct link between the formation of cratons and ultrahigh-temperature metamorphic terrains and the supercontinent cycle. This insight constrains the tectonic settings responsible for crustal differentiation.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Ultra-hot origins of stable continents

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2025年10月13日

查看全文
  • Andrew J. Smye,
  • Peter B. Kelemen

摘要

The origin and composition of Earth’s silica-rich continental crust, particularly the lower crust, remain uncertain. Stable continental crust, including cratons and crust older than 200 million years, is marked by enrichment of radiogenic heat-producing elements (U, Th and K) in the upper crust and depletion in the lower crust. Because the lower crust probably consists of >50% aluminous metasedimentary and evolved metaigneous rocks—both initially enriched in U and Th—continental differentiation requires a mechanism to transfer these elements upwards. Here, in our analysis of partially melted metasedimentary and metaigneous rocks, we show that ultrahigh temperatures (>900 °C) are essential to stratify heat production and stabilize crust. Removal of small fractions of ultrahigh-temperature melt generated by fluid-absent melting can produce the observed lower-crustal depletions in U and Th. By contrast, lower-temperature melting fails to drive differentiation owing to the resilience of monazite to dissolution in granitic melts. Our findings establish ultrahigh-temperature melting as an important criterion for the formation of stable continents, providing a direct link between the formation of cratons and ultrahigh-temperature metamorphic terrains and the supercontinent cycle. This insight constrains the tectonic settings responsible for crustal differentiation.