DOI: 10.1016/j.epsl.2018.07.007
Scopus记录号: 2-s2.0-85050139813
论文题名: The role of subsidence in shelf widening around ocean island volcanoes: Insights from observed morphology and modeling
作者: Quartau R. ; Trenhaile A.S. ; Ramalho R.S. ; Mitchell N.C.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 498 起始页码: 408
结束页码: 417
语种: 英语
英文关键词: insular shelves
; modeling
; shelf break
; subsidence
; Volcanic Ocean Islands
Scopus关键词: Erosion
; Long Term Evolution (LTE)
; Models
; Morphology
; Sea level
; Volcanoes
; Eustatic sea level
; Evolution modeling
; insular shelves
; Relative contribution
; Shelf break
; Shelf development
; Volcanic islands
; Volcanic ocean island
; Subsidence
; bathymetry
; coastal erosion
; coastal morphology
; glacioeustacy
; ocean island basalt
; shelf break
; subsidence
; volcanic island
; Azores
; Faial
; Portugal
; Sao Jorge
英文摘要: On reefless volcanic islands, insular shelves are thought to have formed essentially by the combined effects of wave erosion and glacio-eustatic sea-level oscillations. Subsidence, however, has also been recognized as having an important role in the development of these morphologies. Yet, few studies have quantified the relative contribution of subsidence to shelf generation and development, particularly to shelf width. A better understanding of this contribution, however, is key to understand the long-term evolution of coasts at volcanic islands, particularly given that subsidence may exacerbate the effects of marine erosion. In this study we assess quantitatively the role of subsidence in shelf development by comparing real cross-shore shelf profiles with modeled profiles using varied rates of subsidence. To achieve this, we used shelf bathymetric profiles from Faial and São Jorge islands in the Azores, which we compared with predictions of a numerical model of coastal erosion that has been calibrated previously against other field data. The first set of model runs was made to calibrate the model by determining the values that produced shelves with break depths, widths, and profile shapes that were similar to those observed. The second set of runs, which served to evaluate the contribution of subsidence to shelf widening, revealed that subsidence may have been responsible for increasing shelf widths by almost 2.5 times relative to shelves formed only by the combined effects of wave erosion and glacio-eustatic oscillations. Modeling shelf formation on the same islands but with increased subsidence rates up to 2.2 mm/yr resulted in shelf profiles up to 19 km wide, a value 3 to 6 times greater than observed on these islands. Our study therefore reinforces the idea that subsidence is a key contributor to the generation of broad insular shelves, given its role in enhancing coastal retreat. Our shelf evolution modeling also suggests that, notwithstanding the crucial role subsidence plays in increasing the width of shelves, on islands subjected to energetic wave regimes (as it happens in the Azores and Hawaii), modification by erosion is important enough to result in shelf morphologies that are not constructional in essence, but rather dominantly erosive surfaces. This study therefore contributes to a better understanding of how insular shelves and submarine terraces form and develop by proving important new quantitative insights of the role of subsidence on the generation of these morphologies. © 2018 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109743
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Divisão de Geologia Marinha, Instituto Hidrográfico, Lisboa, Portugal; Department of Earth and Environmental Sciences, University of Windsor, Windsor, Canada; Instituto Dom Luiz, Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal; School of Earth Sciences, University of Bristol, Bristol, United Kingdom; Lamont-Doherty Earth Observatory at Columbia University, New York, United States; School of Earth and Environmental Sciences, University of Manchester, Manchester, United Kingdom
Recommended Citation:
Quartau R.,Trenhaile A.S.,Ramalho R.S.,et al. The role of subsidence in shelf widening around ocean island volcanoes: Insights from observed morphology and modeling[J]. Earth and Planetary Science Letters,2018-01-01,498