Characteristics of Beachrocks: A Review

Danjo, Takashi; Kawasaki, Satoru

doi:10.1007/s10706-013-9712-9

Cited by 28 publications

(19 citation statements)

References 57 publications

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“…The average dynamic Poisson's ratio was 0.16, respectively. Compared with the beach rock samples at other points shown in Table 1, these results show a higher porosity and lower values for both P-wave velocity and S-wave velocity compared to Okinawa, Japan samples [17]. Figure 5 shows the results of comparing the properties of beachrocks with other rock types using existing data.…”

Section: Three Dimensional Of Subsurface Modelmentioning

confidence: 89%

“…In Indonesia, the beachrock plays the role of protecting the coastline from storms, and there are also examples in eastern Kume Island and the Great Barrier Reef in Australia [14,15]. Table 1 summarizes the results of physical and mechanical tests conducted on the beachrock whose geological formation was similar to that in Japan [16,17]. According to previous research, the beachrock was formed only a few thousand years ago, and as its ages, the V P , V S , and mechanical strength increase.…”

Section: Krakal-sadranan Beachrock Characteristicsmentioning

confidence: 99%

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Investigation of Natural Beachrock and Physical–Mechanical Comparison with Artificial Beachrock Induced by MICP as a Protective Measure against Beach Erosion at Yogyakarta, Indonesia

et al. 2020

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Typically, the mitigation of coastal erosion is achieved by amending surface conditions using materials, such as concrete. The objective of this study is to evaluate the feasibility of constructing artificial beachrocks using natural materials (e.g., microbes, sand, shell, pieces of coral, and seaweed, etc.) within a short time, and to propose the method as a novel strategy for coastal protection. Initially, a survey on resistivity and a multichannel analysis of seismic waves (MASW) were conducted along the coastal lines to characterize and elucidate the subsurface structure of existing beachrocks in the Southeast Yogyakarta coastal area, Krakal-Sadranan beach, Indonesia. The field survey on natural beachrocks suggested that both resistivity and shear wave velocity were higher in the deeper deposits compared to the underlying unconsolidated sand layer within a depth of approximately 1.5 m and covering an area of 210.496 m 2 for the α-section and 76.936 m 2 for the β-section of beachrock deposit. The results of the sand solidification test in the laboratory showed that treated sand achieved unconfined compressive strength of up to around 6 MPa, determined after a treatment period of 14 days under optimum conditions.

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Section: Three Dimensional Of Subsurface Modelmentioning

confidence: 89%

Section: Krakal-sadranan Beachrock Characteristicsmentioning

confidence: 99%

Investigation of Natural Beachrock and Physical–Mechanical Comparison with Artificial Beachrock Induced by MICP as a Protective Measure against Beach Erosion at Yogyakarta, Indonesia

et al. 2020

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“…Extensive studies carried out on beachrocks all over the world have shown that tropical and subtropical climates are more preferred for beachrock formation and over 90% of the occurrences are between 40°N and Tropic of Capricorn (Danjo and Kawasaki 2014). However, sporadic occurrences in temperate regions and cold areas have been identified by more recent investigations, thus eliminating the idea that beachrocks are a characteristic feature in tropical and subtropical regions (Kneale and Viles 2000;Cooper et al 2017).…”

Section: Communicated By M V Alves Martinsmentioning

confidence: 99%

Distribution and cementation characteristics of beachrocks along southern, southwestern and western coast of Sri Lanka

Nayanthara

Dassanayake

Nakashima

et al. 2020

J. Sediment. Environ.

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Beachrocks are sedimentary structures where gravelly or sandy beaches have been transformed into rock outcrops formed through precipitation of connective cements amid their interstices. They are well-noted coastal features along the coastal belt of Sri Lanka due to the prevalent tropical climate. This study was aimed at gathering data on surface nature and cementation characteristics of beachrock occurrences along a part of Sri Lankan shoreline through field observations and a series of analyses including X-ray diffraction, X-ray fluorescence, scanning electron microscopy (SEM) techniques and petrographic thin-section analysis. The combined research findings from different techniques are also employed as a preliminary step to determine the formation mechanism of the studied beachrocks. The seaward-inclined low-angle beds running parallel to present shoreline are composed mostly of sandstone with occasional conglomerate. Almost all the beachrocks are made of quartz grains amalgamated by cement. One remarkable feature of Sri Lankan beachrocks is the presence of heavy minerals generally in thin lamina form. The cementing agents are predominantly composed of metastable carbonate phases, high magnesium calcite (HMC) and aragonite (Ar) with varying microfabrics and textures. From SEM examinations and thin-section images, main morphologies identified are acicular Ar, scalenohedral magnesium calcites along with bridge cements and micritic coatings which are typical of a marine-phreatic precipitation with the exception of occasional meniscus cements. Further, the presence of evidences of living organisms may be an indication of influence from the biological aspects which can be confirmed by more detailed analyses.

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“…Over 90 % of beachrocks are distributed between the proximity of 40 0 N latitude and the Tropic of Capricorn, and that their formative periods range from 26,000 years to just a few decades ago [18]. Beach of Bangladesh located between 20 0 35 / N to 22 0 50 / N latitude and 89 0 06 / E to 92 0 21 / E longitude.…”

Section: Properties Of Beachrockmentioning

confidence: 99%

“…2). The main components of beachrocks and surrounding material are calcium carbonate or silica [18].…”

Section: Properties Of Beachrockmentioning

confidence: 99%

Artificial Beachrock Formation Through Sand Solidification Towards the Inhibit of Coastal Erosion in Bangladesh

Khan¹

2015

geomate

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Erosion is a great problem in the coast areas of Bangladesh. The present study was conducted through literature survey to evaluate the prospects of making artificial beachrock through sand solidification for the protection from coastal erosion in Bangladesh. On average, recession through erosion due to sea level rise (SLR) in the coast of Bangladesh will occur 0.87m per 1cm rise in sea level. Artificial beachrocks have the potentials to inhibit coastal erosion. Beachrock is a type of sedimentary deposit that generally occurs on tropical and subtropical beaches as a result of intertidal lithification of loose beach sands and gravels by carbonate cementation. Chemically, beachrock around the world differs in composition but mainly it composed of CaCO3 and SiO2. Beachrocks are cemented by high Mg calcite (HMC) with the influence on precipitation from seawater and/or seawater evaporation (PSW) and on surface microorganisms, bacterial ureolysis. On 30 0 C curing temperature which is similar to the average temperature in Bangladesh beach sand solidified 5 to 8 MPa unconfined comprehensive strength (UCS) in 28 curing days using the ureolytic bacteria (Pararhodobacter sp.). It is concluded that it may be possible to manufacture artificial rocks through sand solidification similar to beachrocks for erosion control purposes in Bangladesh.

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Characteristics of Beachrocks: A Review

Cited by 28 publications

References 57 publications

Investigation of Natural Beachrock and Physical–Mechanical Comparison with Artificial Beachrock Induced by MICP as a Protective Measure against Beach Erosion at Yogyakarta, Indonesia

Investigation of Natural Beachrock and Physical–Mechanical Comparison with Artificial Beachrock Induced by MICP as a Protective Measure against Beach Erosion at Yogyakarta, Indonesia

Distribution and cementation characteristics of beachrocks along southern, southwestern and western coast of Sri Lanka

Artificial Beachrock Formation Through Sand Solidification Towards the Inhibit of Coastal Erosion in Bangladesh

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