A Simple Model for Plate Motion and Topography

Öz

The traditional explanation of slow dynamic subsidence and uplift of tectonic plates solely depends on the vertical motion of mantle density anomalies. This has been challenged by observations of rapid and short-lived elevation changes exceeding 100 meters per-million-year in numerous sedimentary basins. Bodur et al., (2023) have shown that relative tectonic plate motion and associated basal shear stress can explain those rapid and short-lived elevation changes. In this paper, I suggest a basic approach to quantify elevation changes resulting from basal shear stress by employing torque-balance calculations. The results confirm the existing flow model solution and offer a more robust formula for estimating the impact of plate motion on changes in Earth's topography. Such functionality may prove invaluable in various applications including interpretation of stratigraphic records.

Anahtar Kelimeler

• Dynamic topography
• tectonic plate motion
• basal shear stress
• torque balance
• stratigraphy
• Earth's topography

Tektonik Levha Hareketiyle Oluşan Topoğrafyanın Fiziksel Modeli

Öz

Kıtaların dinamik olarak yavaşça alçalması ve yükselmesi, Dünya’nın mantosundaki yoğunluk anomalilerinin (alçalan yitmiş levha ya da manto yükselmesi) hareketine dayandırılır. Ancak, birçok sedimanter havzada milyon yıl başına 100 metreyi aşan hızlı ve kısa ömürlü yükseklik değişikliklerinin gözlemleri, sadece bu mekanizmanın dinamik dikey kıta hareketlerini tetiklediği görüşünü sorgulatmıştır. Bodur vd. (2023) tektonik yatay levha hareketinin ve bununla ilintili taban kayma gerilmesinin, gözlemlenen hızlı ve kısa ömürlü kıta yükselme ve alçalmalarını açıklayabileceğini göstermiştir. Bu makalede, taban kayma gerilmesinden kaynaklanan kıtasal yükseklik değişikliklerini nicelendirmek için tork-denge hesaplamalarını kullanarak temel fiziksel bir yaklaşım öneriyorum. Elde ettiğim sonuçlar, mevcut akış modeli çözümünü doğrulamakta ve Dünya'nın topoğrafyasındaki levha hareketinin etkisini tahmin etmek için daha kolay kullanılabilir bir formül sunmaktadır. Bu tür işlevsellik, stratigrafik kayıtların yorumlanması dahil olmak üzere birçok uygulamada faydalı olabilir.

Anahtar Kelimeler

• Dinamik topoğrafya
• tektonik levha hareketi
• kayma gerilimi
• tork dengesi
• stratigrafi
• Dünya'nın topoğrafyası

Kaynakça

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