A comparative study of modern carbonate mud in reefs and carbonate platforms: Mostly biogenic, some precipitated

Gischler, Eberhard; Dietrich, Sarah; Harris, David; Webster, Jody M.; Ginsburg, Robert N.

doi:10.1016/j.sedgeo.2013.04.003

Cited by 53 publications

(48 citation statements)

References 51 publications

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“…The dimensions and shapes of mud particles produced experimentally by abrading natural marine ooids were indistinguishable from carbonate mud filtered from seawater collected at the same field site and were comparable to the aragonite needles that define the fabric of the ooid cortices (Figure S4). Similarly, the heterogeneity of particle dimensions and shapes produced by abrasion of skeletal carbonate send resembles carbonate mud from Florida Bay (Schieber et al, ) and other settings dominated by skeletal grains rather than ooids (Gischler et al, ). Laser‐diffraction particle size analyses of the carbonate mud confirmed SEM observations that distributions of particle sizes were most sensitive to the initial sand composition rather than sand size or transport mode (Figure c).…”

Section: Resultsmentioning

confidence: 95%

The Origin of Carbonate Mud

Trower

Lamb

Fischer

2019

Geophysical Research Letters

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Carbonate mudstones are key geochemical archives for past seawater chemistry, yet the origin of carbonate mud remains a subject of continued debate and uncertainty. Prevailing hypotheses have settled on two mechanisms: (1) direct precipitation in the water column and (2) postmortem dispersal of mud‐sized algal skeletal components. However, both mechanisms conflict with geochemical observations in modern systems and are problematic in deep time. We tested the hypothesis that abrasion of carbonate sand during sediment transport might produce carbonate mud using laboratory experiments and a sediment transport model. We documented experimental mud production rates up to two orders f magnitude faster than rates estimated for other mechanisms. Combined with model calculations, these results illustrated that transport and abrasion of carbonate sand is a major source of carbonate mud.

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Section: Resultsmentioning

confidence: 95%

The Origin of Carbonate Mud

Trower

Lamb

Fischer

2019

Geophysical Research Letters

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“…However, determining the origins of mud-grade (<63 µm) carbonates can be problematic (Flügel, 2004). Much shallow mud production has been ascribed to post-mortem breakdown of carbonate-secreting taxa (especially codiacean algae and seagrass epiphytes) along with microbially mediated and abiotic precipitation (see Gischler et al, 2013). In addition, evidence has emerged that all bony marine fishes (teleosts) precipitate mud-sized carbonates in their intestines (Walsh et al, 1991), and that these can be excreted at rates relevant to carbonate sediment budgets-especially in habitats with high fish biomass, such as coral reefs (Perry et al, 2011;Salter et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Reef fish carbonate production assessments highlight regional variation in sedimentary significance

Salter

Perry

Stuart‐Smith

et al. 2018

Geology

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Recent studies show that all marine bony fish produce mud-sized (<63 µm) carbonate at rates relevant to carbonate sediment budgets, thus adding to the debate about the often enigmatic origins of finegrained marine carbonates. However, existing production data are geographically and taxonomically limited, and because different fish families are now known to produce different carbonate polymorphsan issue relevant to predicting their preservation potential-these limitations represent an important knowledge gap. Here we present new data from sites in the Western Pacific Ocean, based on an analysis of 45 fish species. Our data show that previously reported production outputs (in terms of rates and family-specific mineralogies) are applicable across different biogeographic regions. On this basis, we model carbonate production for nine coral reef systems around Australia, with production rates averaging 2.1-9.6 g m -2 yr -1 , and up to 105 g m -2 yr -1 at discrete sites with high fish biomass. With projected production rates on lower-latitude reefs up to two-fold higher, these outputs indicate that carbonate production rates by fish can be comparable with other fine-grained carbonate-producing taxa such as codiacean algae. However, carbonates produced by Australian reef fish assemblages are dominated by a highly unstable amorphous polymorph; a marked contrast to Caribbean assemblages in which Mg calcite dominates. These findings highlight important regional differences in the sedimentary relevance and preservation potential of fish carbonates as a function of historical biogeographic processes that have shaped the world's marine fish faunas.

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“…However, in most cases clear evidence for such an origin is enigmatic at best, and thus a range of known contemporary sources of mud-grade carbonate are usually invoked to explain mud production, these including: 1) mechanical and/or biological break down of skeletal carbonates, such as calcareous green algae and calcareous seagrass epiphytes (Lowenstam and Epstein, 1957;Land, 1970;Nelsen and Ginsburg, 1986;Gischler and Zingeler, 2002;Gischler et al, 2013); 2) biogenically-induced precipitation, such as that associated with microbial activity and blooms of unicellular algae; a process that has been linked to 'whiting' events (Greenfield, 1963;Robbins and Blackwelder, 1992;Robbins, 1995, 2001); and 3) abiotic precipitation, which has also been linked with 'whiting' events (Shinn et al, 1989;Milliman et al, 1993;Morse et al, 2003). In addition, recent studies have identified teleost (bony) fish as important contributors to global marine carbonate production (Wilson et al, 2009) and as a potentially important source of mud-grade carbonate, especially in sites of high fish biomass (Perry et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Size fraction analysis of fish-derived carbonates in shallow sub-tropical marine environments and a potentially unrecognised origin for peloidal carbonates

Salter¹,

Perry²,

Wilson³

2014

Sedimentary Geology

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Marine bony fish are now known as primary producers of calcium carbonate. Furthermore, within the shallow sub-tropical platform settings of the Bahamas, this production process has been shown to occur at rates relevant to carbonate sediment production budgets. Fish excrete these carbonates as loosely aggregated pellets which, post-excretion, exhibit a range of distinctive crystal morphologies and have mineralogies ranging from low (0-4 mol% MgCO 3 ) to high (4-40 mol% MgCO 3 ) Mg-calcites, aragonite and amorphous carbonate phases. Here we provide the first quantitative assessment of the size fractions of the carbonates produced by a range of tropical fish species, and document the extent of post-excretion carbonate pellet break down under a range of physical agitation conditions. Specifically, we document the morphologies and size fractions of: i) intact pellets at the point of excretion; ii) intact pellets after agitation in seawater; and iii) the particles released from pellets post-disaggregation. Results indicate that fish-derived pellets initially fall within the very fine to very coarse sand fractions. Exposure to conditions of moderate seawater agitation for 30 days results in significant pellet diminution; 66% of initial pellet mass being released as individual particles, whilst 34% is retained as partially intact pellets that are smaller (fine sand-grade) and more rounded than initial pellets. In contrast, pellets exposed to very gently agitated conditions for up to 200 days show little change. Where pellet disaggregation does occur, particles are commonly released as individual clay-and silt-grade crystals. However, some morphotypes (e.g., polycrystalline spheres) can be intergrown and are released as strongly cohesive particle clusters falling within the coarse silt to fine sand fractions. Only very vigorous agitation may disaggregate such particles, resulting in the release of their component clay-grade crystals. We conclude that fish-derived carbonates may thus contribute not only to the mud-fraction of marine carbonates, but also to the fine sand fraction as intergrown particles, and to the fine to coarse sand fractions as intact and partially intact pellets. These experimental data indicate that hydrodynamic regimes local to sites of excretion will influence the generation of carbonates with different size fraction ranges. Rapid pellet disaggregation is more likely in high energy settings, hypothesised to result in redistribution of liberated mud-grade particles to lower energy platform-top settings and/or offplatform. In contrast, pellets excreted in lower energy settings are more likely to be preserved intact, and are thus proposed as a previously unrecognised source of pelletal and peloidal carbonate sediments.

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A comparative study of modern carbonate mud in reefs and carbonate platforms: Mostly biogenic, some precipitated

Cited by 53 publications

References 51 publications

The Origin of Carbonate Mud

The Origin of Carbonate Mud

Reef fish carbonate production assessments highlight regional variation in sedimentary significance

Size fraction analysis of fish-derived carbonates in shallow sub-tropical marine environments and a potentially unrecognised origin for peloidal carbonates

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