Stratigraphy, geometry, and facies of a Middle Devonian ramp-to-basin transect (Eastern Anti-Atlas, SE Morocco)

Döring, Sascha; Kazmierczak, Marion

doi:10.1007/bf02668171

Cited by 18 publications

(23 citation statements)

References 9 publications

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“…The main diVerence is that in the hemi-pelagic ridge setting allodapic lowstand aprons overly a correlative sequence boundary marked by the lowest wave-base, while on the shallow ramp neritic carbonates overly a subaerial exposure surface and continued carbonate production leads to progradation and development of the maximum regressive surface on top of the lowstand deposits. In this sense, the Middle Devonian sequences studied in the Maider Basin on down-dip shallow ramp to basin transects have been correctly interpreted by Döring and Kazmierczak (2001), who, for example, placed the maximum regressive surface of their hemi-cycle 3 on top of the Late Eifelian lowstand wedge. On all northern TaWlalt hemi-pelagic ridge sections however, the maximum regressive surface (T/R-sequence boundary) would have to be placed at the base of the lowstand deposits and would be correlated to the lowest relative sea level and maximum wave-base feeling.…”

Section: T/r-cycle Boundaries In the Hemi-pelagic Ridge Settingmentioning

confidence: 87%

“…Along the southern and western margin of the Maider Basin, shallow-water coral and stromatoporoid limestones were formed in a mid-ramp setting during the Middle Devonian (Döring and Kazmierczak 2001;Döring 2002). Shallow-water carbonates also formed on the northern margin of the Maider Basin on an isolated, uplifted fault-block (Jebel Rheris, Fig.…”

Section: Geological Background and Stratigraphymentioning

confidence: 98%

“…The bulk of the carbonate material therefore is more likely to have been supplied from the shallow-marine Maider Platform in the south, where coral and stromatoporoid biostromes occur in the Middle Devonian succession (Döring and Kazmierczak 2001), and not from the TaWlalt ridge of the studied area or TaWlalt Platform to the north.…”

Section: Fig 8 Middle Givetianmentioning

confidence: 99%

“…The basins were separated by a narrow ridge, with cephalopod limestones, which broadened towards the north to form a wider swell (TaWlalt Platform sensu Wendt 1988). Water depths in the basins were interpreted to have been far below storm wave-base (Döring and Kazmierczak 2001) but probably did not exceed the order of 100-200 m during the Middle Devonian and only during the Late Devonian may have reached 200-400 m (Wendt et al 1984).…”

Section: Geological Background and Stratigraphymentioning

confidence: 99%

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Controls on Devonian hemi-pelagic limestone deposition analyzed on cephalopod ridge to slope sections, Eastern Anti-Atlas, Morocco

Lubeseder

Rath

Rücklin

et al. 2009

Facies

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The hemi-pelagic TaWlalt Ridge separating the Maider Basin from the TaWlalt Basin developed progressively from an Early Devonian homoclinal ramp, through a Middle Devonian ramp-slope stage of moderate topography, to a mature cephalopod ridge during the Late Devonian and formed a spur-like element extending from the southern shallow-water Maider Platform to the broader northern hemi-pelagic TaWlalt Platform. During the Middle Devonian, thick lowstand aprons were shed onto the ridgeslope from an active mid-ramp carbonate factory in the south (Maider Platform). The shallow-water derived sediments Wrst by-passed the central paleohigh, but then onlapped the ridge during start of sea-level rise. The allodapic limestones (storm-induced turbidites, tempestites, and debrites) of the aprons consist of large parts or entirely of reworked lithic peloids. The lithic peloids are interpreted as the main foundation of all micritic lithofacies types in the distal ramp locations, including those on the hemi-pelagic cephalopod ridge. Lateral facies transition of allodapic limestones into nodular cephalopod limestones on the ridge suggests the latter originate from allodapic beds and were subsequently transformed into nodular limestones by bioturbation, early diagenesis, and the faunal input from a hemi-pelagic community. Iron-rich hardgrounds formed on the ridge during major regressive phases as a result of increased winnowing by the wave-base and correlate with siliciclastic turbidite deposition on the slope. The hardgrounds can be correlated with hiatuses on the TaWlalt Platform, which formed a broader hemi-pelagic swell to the north. During the Late Devonian, the southern Maider Basin carbonate factory became unproductive or disappeared, and a ridge facies of truly hemi-pelagic autochthonous limestones developed. Allodapic deposits on the slope were shed from the ridge itself at this time but did not form well-deWned aprons.

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Section: T/r-cycle Boundaries In the Hemi-pelagic Ridge Settingmentioning

confidence: 87%

Section: Geological Background and Stratigraphymentioning

confidence: 98%

Section: Fig 8 Middle Givetianmentioning

confidence: 99%

Section: Geological Background and Stratigraphymentioning

confidence: 99%

See 2 more Smart Citations

Controls on Devonian hemi-pelagic limestone deposition analyzed on cephalopod ridge to slope sections, Eastern Anti-Atlas, Morocco

Lubeseder

Rath

Rücklin

et al. 2009

Facies

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show abstract

“…Fortunately, the arid climate keeps vegetation to a minimum in the Moroccan pre‐Sahara, thus creating extensive outcrops. Therefore, thickness and facies changes can be examined in space and through geological time in order to reconstruct the arrangement of basins and carbonate ramps as well as the approximate course of coastlines throughout the Devonian (Hollard ; Wendt , ; Wendt & Belka ; Kaufmann ; Döring & Kazmierczak ; Lubeseder et al . ).…”

mentioning

confidence: 99%

Fossil‐Lagerstätten, palaeoecology and preservation of invertebrates and vertebrates from the Devonian in the eastern Anti‐Atlas, Morocco

Frey

Pohle

Rücklin

et al. 2020

LET

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In some Devonian strata in the eastern Anti‐Atlas, fossil invertebrates are abundant, display a high taxonomic diversity and indicate many shifts in palaeoecology. This is reflected in changes in faunal composition of invertebrates and vertebrates. Fossils of jawed vertebrates of late Lochkovian and younger age have been recorded and are relatively common with their abundance and diversity increasing towards the Late Devonian. Environmental changes in the Devonian also left their mark in the preservation of vertebrates and invertebrates from the Anti‐Atlas, which varies strongly through time and regionally. This variation partially reflects environmental changes linked with the evolution of small marine basins during the disintegration of the continental shelf of Gondwana in this region, fluctuations of the regional sea level and other environmental changes. To improve our understanding of these ecological changes, of shifts in preservation through the succession and of the formation of Fossil‐Lagerstätten, we analysed the mineral composition of some invertebrate and vertebrate samples of Devonian and Early Carboniferous age by Raman spectroscopy and X‐ray diffraction. Additionally, we characterized some of these Fossil‐Lagerstätten using palaeontological and sedimentological parameters. We examined eight Devonian Konzentrat‐Lagerstätten and two Konservat‐Lagerstätten with soft‐tissue preservation (the Famennian Thylacocephalan Layer and the Hangenberg Black Shale of the southern Maïder). The last two are the first Konservat‐Lagerstätten described from the Devonian of North Africa. The taphonomic and oceanic settings suggest that these Konservat‐Lagerstätten are formed because of stagnation (related to vertical restriction of water exchange and water depth rather than limited spatial water exchange and a lateral restriction) in the relatively small Maïder Basin with limited water exchange with the neighbouring Tafilalt Basin. The temporally low oxygen levels in the Maïder Basin are a possible reason for the reduced chondrichthyan diversity (missing demersal and shallow water species) compared to the Tafilalt Platform.

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At the southern limits of the Devonian reef zone: Palaeoecology of the Aferdou el Mrakib reef (Givetian, eastern Anti‐Atlas, Morocco)

et al. 2018

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Devonian reefs of north-western Gondwana represent the southernmost record of shallow-water coral reefs in the Palaeozoic. However, few studies have attempted to date palaeoecological reconstructions of these high-latitude reefal buildups. This study provides the first detailed palaeoecological analysis of Aferdou el Mrakib, an isolated, Givetian coral-stromatoporoid reef, which developed in a semirestricted basin in the south-eastern part of the Rheic Ocean. The study documents spatial facies variability and succession of faunal replacements accompanying progressive reef accretion towards the sea surface. The investigations included both autochthonous communities found at the base of the reef and, partially, within the reef core, and allochthonous deposits of reef-derived skeletal debris that accumulated in the fore-reef setting. Contrary to some previous suggestions, the study shows that the Aferdou reef shared many characteristics of classical Middle Devonian coral-stromatoporoid buildups, including the ecological succession, limited role of calcareous algae, and development within the range of the euphotic zone, but likely below the zone of regular water agitation. Critical factors in the facies development and temporal changes in the character of reef building were the palaeobathymetry, dominant sedimentary and circulation regimes, level of wave energy, and, possibly, light availability. Distinctive features of the palaeoecology of Aferdou el Mrakib are the dominance of massive colonies of heliolitid tabulates and a subordinate role of massive stromatoporoids, both explained here primarily as a result of increased water turbidity in the high-latitude sedimentary basin.The growth of the high-latitude coral-stromatoporoid reefs in the south-eastern Rheic Ocean was favoured by a combination of the exceptionally warm climate and plate tectonic configuration typifying the Devonian. Of critical importance appears the palaeogeographic position of the Rheic, which resulted in the seawater circulation in the ocean being dominated by tropical water masses, with restricted inflow of cold water from the circumpolar oceanic circulation.

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Stratigraphy, geometry, and facies of a Middle Devonian ramp-to-basin transect (Eastern Anti-Atlas, SE Morocco)

Cited by 18 publications

References 9 publications

Controls on Devonian hemi-pelagic limestone deposition analyzed on cephalopod ridge to slope sections, Eastern Anti-Atlas, Morocco

Controls on Devonian hemi-pelagic limestone deposition analyzed on cephalopod ridge to slope sections, Eastern Anti-Atlas, Morocco

Fossil‐Lagerstätten, palaeoecology and preservation of invertebrates and vertebrates from the Devonian in the eastern Anti‐Atlas, Morocco

At the southern limits of the Devonian reef zone: Palaeoecology of the Aferdou el Mrakib reef (Givetian, eastern Anti‐Atlas, Morocco)

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