The geomorphology, development and temporal dynamics of Tepuka Island, Funafuti atoll, Tuvalu

Kench, Paul S.; Chan, Jade K.Y.; Owen, Susan; McLean, Roger

doi:10.1016/j.geomorph.2014.03.043

Cited by 38 publications

(49 citation statements)

References 42 publications

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“…In all islands secondary constituents such as molluscs, foraminifera and Halimeda contributed less than 12% each to the sediments. These results are consistent with studies reported elsewhere, which show islands are dominated by coral/coralline algae facies in the Pacific and Indian Ocean (Woodroffe et al, 1999;Kench et al, 2012Kench et al, , 2014a. Janßen et al (2017) also highlight compositional shifts in sediments, which provides insights into ecological transitions in mid-shelf reefs that have implications for sediment production regimes.…”

Section: Reef Islands In the Spermonde Archipelagosupporting

confidence: 91%

“…Initial theories embraced a sequential model of island evolution whereby sea-level stabilization, completion of vertical reef development and reef flat formation at sea level were precursors for the evolution of islands. Supporting evidence of this linear model is found in examples from the midPacific and Indian Oceans, where for the past 6,000 years sea level has been at or slightly higher than present (Woodroffe et al, 1999;Woodroffe and Morrison, 2001;Kench et al, 2012Kench et al, , 2014a. However, disparities in late Holocene sea-level dynamics and reef growth responses (timing and magnitude of change) between reef regions have provided differing boundary conditions and temporal constraints for the onset and accumulation of reef islands.…”

Section: The Role Of Sea Level and Reef Development In Island Formationmentioning

confidence: 77%

“…This model is supported by evidence of islands perched on raised conglomerate in the Indian Ocean (Woodroffe et al, 1999) and emergent reefs at other locations in the Pacific (Kench et al, , 2014b. Second, islands can form across sea-level constrained reef flats, as has been demonstrated in Tuvalu (McLean and Hosking, 1991;Kench et al, 2014a) and Fiji (McKoy et al, 2010). The third model allows reef island formation over submerged reefs and sedimentary deposits as sea-level rise slowed toward the mid-Holocene highstand as demonstrated in the Maldives (Kench et al, 2005(Kench et al, , 2009a.…”

Section: The Role Of Sea Level and Reef Development In Island Formationmentioning

confidence: 77%

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Reef Island Evolution and Dynamics: Insights from the Indian and Pacific Oceans and Perspectives for the Spermonde Archipelago

Kench

Mann

2017

Front. Mar. Sci.

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Along southwestern Sulawesi, Indonesia, the Spermonde Archipelago comprises some 120 islands of variable size and degree of anthropogenic modification. Comparable to adjacent areas in Southeast Asia, the Spermonde Archipelago is characterized by the congregation of a naturally high marine biodiversity and, at the same time, a high population density influencing the surrounding environmental conditions. As a consequence, during the last decades, research projects that have been carried out in the Spermonde mainly focused on social, ecological, political and economic interactions. However, geological and geomorphological aspects of the coral reef islands are less well understood and there have been few studies undertaken since the pioneering work of Umbgrove, Kuenen, and Verstappen in the Indonesian archipelago in the early to mid-twentieth century. Here we review the existing studies, with a focus on the Spermonde Archipelago, and reconcile them with more recent works on reef island evolution and dynamics from the Indian and Pacific Oceans. This synthesis shows that reef islands in the Spermonde Archipelago are well suited for geomorphological investigations, and provides perspectives for future reef island research in that area that will have global interest. We identify four research priorities: (1) To identify the timing and chronology of island formation; (2) Improved understanding of carbonate budgets and sediment generation that contribute to island building; (3) Document morphological changes in reef islands at seasonal to decadal timescales, and; (4) Quantify the process regime that drives sediment transport and island change with particular focus on the role of different monsoon seasons.

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Section: Reef Islands In the Spermonde Archipelagosupporting

confidence: 91%

Section: The Role Of Sea Level and Reef Development In Island Formationmentioning

confidence: 77%

Section: The Role Of Sea Level and Reef Development In Island Formationmentioning

confidence: 77%

See 1 more Smart Citation

Reef Island Evolution and Dynamics: Insights from the Indian and Pacific Oceans and Perspectives for the Spermonde Archipelago

Kench

Mann

2017

Front. Mar. Sci.

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“…For coral reef science, atoll geology and island geomorphology, Funafuti has great historical significance and to this day the Funafuti boring has been referred to as "an old friend" (Ohde et al, 2002). Moreover, the maps surveyed in 1897 have been used as a baseline to document changes extending over 100 year period for Fongafale Island (Sheet 7) in the east of the atoll (Yamano et al, 2007) and Tepuka (Sheet 12) in the west (Kench et al, 2014) Second, it is also surprising that the incomplete notes and descriptions were not commented upon by Professor T.G. Bonney who was responsible for editing The Atoll of Funafuti, and even more remarkable that authors David and Sweet did not comment on the missing data.…”

Section: Discussionmentioning

confidence: 99%

Recovery of Missing Explanatory Notes of the First Geological Map of Funafuti Atoll, 1904

McLean¹

2014

Atoll Research Bulletin

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“…For example in the Maldives, 75% of the estimated annual sand-sized sediment budget on the reef flat was produced on the reef-flat rim (ocean-side) (Perry et al, 2015). The rate of motu formation on the atolls varies greatly from decadal to millennial timescales (Kench et al, 2014a;Woodroffe and Morrison, 2001;Woodroffe et al, 2007;Ford and Kench, 2014).…”

Section: Atolls Reef Flats and Motumentioning

confidence: 99%

Investigating the evolution and formation of coastlines and the response to sea-level rise

Ortiz¹

2015

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To understand how waves and sea level shape sandy shoreline profiles, I use existing energetics-based equations of cross-shore sediment flux to describe shoreface evolution and equilibrium profiles, utilizing linear Airy wave theory instead of shallow-water wave assumptions. By calculating a depth-dependent characteristic diffusivity timescale, I develop a morphodynamic depth of shoreface closure for a given time envelope, with depth increasing as temporal scale increases. To assess which wave events are most important in shaping the shoreface in terms of occurrence and severity, I calculate the characteristic effective wave conditions for both cross-shore and alongshore shoreline evolution. Extreme events are formative in the cross-shore shoreface evolution, while alongshore shoreline evolution scales linearly with the mean wave climate. Bimodal distributions of weighted wave heights are indicative of a site impacted more frequently by tropical storms rather than extra-tropical storms.To understand how offshore wave climate and underlying geometry of a carbonate reef platform shapes evolution of atolls, I simulate the hydrodynamics of a simplified reef flat, using XBeach, a two-dimensional model of infragravity wave propagation. The reef flat self-organizes to a specific width and water depth depending on the offshore wave climate and characteristics of the available sediment. Formation of a sub-aerial landmass, like a motu, can be initiated by a change in offshore wave climate (like a storm), which can create a nucleation site from mobilization and deposition of coarse sediment on the reef flat. Once a motu is present, the shoreline should prograde until reaching a critical reef-flat width. Our conceptual model of reefflat evolution and motu formation is governed by understanding the hydrodynamics of the system and subsequent response of sediment transport. 4 Chapter 1 -IntroductionClimate change has many diverse and severe impacts on our planet, including accelerated rates of sea-level rise. Over the past twentieth century, eustatic sea level rose around 1.5 -2.0 mm/yr (IPCC, 2013; Cazenave et al., 2014; Hay et al., 2015), and predicted rates of eustatic sealevel could far exceed 5 mm/yr in by the end of coming century (IPCC, 2013;Horton et al., 2014;Kopp et al., 2014). Understanding the response of coastal systems to increased rates of sea-level rise is important; 10% of the world's population lives in the Low Elevation CoastalZone (IPCC, 2014; Wong et al., 2014). My research has focused on understanding the processes that shape different coastal systems and how these systems evolve. I am interested in the response of coastal sandy and carbonate sedimentary systems to changes in sea level and predicting how future climate might impact coastal evolution.Geomorphology is the study of landscape evolution through time: by understanding the processes that shape the landscape, it is possible to predict how a landscape may respond to changing forces. Changes in sediment flux can be a primary driver of coast...

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The geomorphology, development and temporal dynamics of Tepuka Island, Funafuti atoll, Tuvalu

Cited by 38 publications

References 42 publications

Reef Island Evolution and Dynamics: Insights from the Indian and Pacific Oceans and Perspectives for the Spermonde Archipelago

Reef Island Evolution and Dynamics: Insights from the Indian and Pacific Oceans and Perspectives for the Spermonde Archipelago

Recovery of Missing Explanatory Notes of the First Geological Map of Funafuti Atoll, 1904

Investigating the evolution and formation of coastlines and the response to sea-level rise

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