Tektonik Levha Hareketiyle Oluşan Topoğrafyanın Fiziksel Modeli

Year 2024, Volume: 67 Issue: 4, 85 - 91, 28.07.2024

Ömer Faruk Bodur

https://doi.org/10.25288/tjb.1459797

Abstract

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.

Keywords

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

A Simple Model for Plate Motion and Topography

Abstract

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.

Keywords

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

Ethical Statement

The research presented in this study received funding from the Australian Research Council (grant no. IH130200012) during my doctoral studies at The University of Sydney, but the completion of this article was entirely self-funded. I would like to express my gratitude for insightful discussions with Patrice Rey, Greg Houseman, and the invaluable feedback provided by my PhD thesis reviewers, Robert Moucha and Giampiero Iaffaldan on the early version of the calculations.

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