Composition and origin of temperate skeletal carbonate sediments on South Maria Ridge, northern New Zealand

Nelson, Campbell S.; Hancock, Graeme E.

doi:10.1080/00288330.1984.9516044

Cited by 35 publications

(11 citation statements)

References 27 publications

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“…Warm-water 'tropical' carbonate sediments are well known and provide modern facies analogues for many limestones in the geological record (Wilson, 1975;Scholle, Bebout & Moore, 1983;James, 1984). Less is understood about the facies of modem, cool-, 'temperate' water carbonate sediments (Lees & Buller, 1972;Nelson, 1978Nelson, , 1988aRao, 1981;Nelson & Hancock, 1984;Scoffin, 1986) and they are rarelyused as models for interpreting ancient rocks. This is largely because there are relatively few documented Tertiary and Quaternary cool-water platform limestones to give the perspective of the third dimension to actualistic facies models.…”

Section: Introductionmentioning

confidence: 99%

Origin of a cool‐water, Oligo‐Miocene deep shelf limestone, Eucla Platform, southern Australia

1991

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The Abrakurrie Limestone is an areally extensive, bryozoan‐rich unit within the Eucla Platform, a Tertiary carbonate shelf which caps the central part of the southern Australian continental margin. The onshore portion, the topic of this study, has been exposed since middle Miocene time and lies beneath the Nullarbor Plain. The rocks are fine‐sand‐ to granule‐sized calcarenites, composed of bryozoans, bivalves, benthic foraminifera and echinoids with lesser numbers of brachiopods, solitary corals and serpulids. They conspicuously lack significant numbers of planktonic foraminifera and coralline algae. Most bryozoan remains are from delicate branching cyclostomes although delicate branching, robust branching, foliose, fenestrate, multilaminar encrusting and free‐living cheilostomes are variably abundant in specific units. The poorly lithified sequence is punctuated by well‐cemented layers with erosional tops, which are interpreted as hardgrounds. The limestone is interpreted as a cool‐water, deep shelf deposit which accumulated in water depths generally greater than 50 m on the inner part of the Eucla Platform. A model which involves deposition and cementation on a carbonate shelf swept by open ocean swells is proposed to explain the style of sedimentation. The shelf is envisaged as partitioned by the depth of the zone of wave abrasion. Sediments were produced throughout, but accumulated only below this depth. When the seafloor was above this depth it was an environment of cementation and erosion. The vertical sequence correlates in a general way with the global sea‐level model for the mid‐Cenozoic. While accumulation rates for southern Australian carbonates are similar to rates of cool‐water carbonate deposition elsewhere (c. 2.5 cm kyr‐1), the rate of Abrakurrie accumulation is much less, suggesting that significant time periods are represented by the hardgrounds.

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Section: Introductionmentioning

confidence: 99%

Origin of a cool‐water, Oligo‐Miocene deep shelf limestone, Eucla Platform, southern Australia

1991

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“…A distribuição das assembleias biogênicas e do grau de conservação, no sedimento da área do Canal de Salvador, indica a ocorrência de modificações na comunidade biótica em função da localidade, confirmando a sugestão de Carannante et al (1988), Nelson & Hancock (1984) e Perry (1996, de que fatores ambientais locais podem produzir importantes variações na composição do sedimento biogênico. Os valores da frequência entre os biogênicos atuais e relíquias geralmente se apresentam bastante diferentes em quase todas as amostras analisadas (figura 4).…”

Section: Resultados E Discussõesunclassified

Distribuição dos componentes biogênicos nos sedimentos da área do Canal de Salvador, Baía de Todos os Santos, Bahia

Poggio¹,

Souza²,

Alves³

et al. 2009

ABEQUA

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O trabalho apresenta uma análise preliminar da composição biogênica dos sedimentos de fundo do Canal de Salvador, uma das principais vias de acesso à Baía de Todos os Santos. Para caracterizar a composição biogênica e avaliar os grupos de organismos contribuintes à produção dos sedimentos carbonáticos recentes, foram utilizadas amostras de sedimentos de fundo das quais 300 grãos foram identificados nas frações granulométricas maiores que 0,125mm. A ocorrência de biogênicos se mostrou inversamente relacionada com a profundidade e diretamente relacionada com o teor de carbonato. Entre os componentes biogênicos carbonáticos, os que tiveram mais representatividade nos sedimentos de fundo foram os moluscos, com 30,2% de frequência. Além disso, os moluscos são os que mais contribuem ativamente para a formação dos sedimentos carbonáticos atuais do local, pois em quase todas as estações amostradas suas carapaças ocorrem de forma bem preservada.

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“…Experimental flume data presented by Nelson & Hancock (1984) show that skeletal fragments are moved by lower current velocities than are required to initiate transpo:-i of quartz grains. For example, coarse sand-sized, porou > bryozoan fragments may be moved by current velocities at 15 cm/s, whereas coarse sand-sized quartz grains requir velocities in the range of 20-30 cm/s (Nelson & Hancoci 1984;Carter & Lewis 1995).…”

Section: Hydraulic Regimementioning

confidence: 99%

Distribution and control of mixed terrigenous‐carbonate surficial sediment facies, Wanganui shelf, New Zealand

Gillespie

Nelson

1996

New Zealand Journal of Geology and Geophysics

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Shallow-marine, mixed temperate, terrigenouscarbonate sediments are accumulating on the shallow to deep Wanganui shelf (c. 20-110 m water depth). From cluster analysis of textural and compositional parameters, five surficial sediment facies and five subfacies have been defined for the shelf. Facies 1 (Bivalve-bearing [gravelly] sand), is a terrigenous-dominated, shallow shelf facies (<50 m), incorporating Subfacies la (Sand)-a modern felsic sand prism-and lb (Bivalve-bearing volcaniclastic gravelly sand)-modern to relict andesitic detritus and shell fragments. Facies 2 (Skeletal-dominated sandy gravel) comprises sediments containing >50% CaCO 3 , and occurs in the shallow to mid shelf region (c. 30-90 m) where levels of terrigenous input are reduced, and substrates and hydraulic conditions are favourable for carbonate production. Facies 2 comprises Subfacies 2a (Bivalve-dominated sandy gravel), 2b (Bryozoan/bivalve-dominated sandy gravel), and 2c (Bryozoan/bivalve-dominated muddy sandy gravel and gravelly muddy sand). Facies 2 sediments are

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Composition and origin of temperate skeletal carbonate sediments on South Maria Ridge, northern New Zealand

Cited by 35 publications

References 27 publications

Origin of a cool‐water, Oligo‐Miocene deep shelf limestone, Eucla Platform, southern Australia

Origin of a cool‐water, Oligo‐Miocene deep shelf limestone, Eucla Platform, southern Australia

Distribuição dos componentes biogênicos nos sedimentos da área do Canal de Salvador, Baía de Todos os Santos, Bahia

Distribution and control of mixed terrigenous‐carbonate surficial sediment facies, Wanganui shelf, New Zealand

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