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Journal Article

A hot, hydrothermally influenced microbial-tidal flat setting in the Palaeoarchaean Moodies Group, Barberton Greenstone Belt, South Africa Available to Purchase

H. Stengel, C. Heubeck, M. Homann
Published: 01 June 2024
South African Journal of Geology (2024) 127 (2): 141–162.
DOI: https://doi.org/10.25131/sajg.127.0017
...H. Stengel; C. Heubeck; M. Homann Abstract Sandy, microbial-mat-laminated sediments are common in estuarine and tidal environments of the Palaeoarchean Moodies Group ( ca. 3.22 Ga); they are interspersed with numerous expressions of mafic to intermediate (sub-) volcanism, including sills, stockwork...
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View PDF for article title, A hot, hydrothermally influenced microbial-tidal flat setting in the Palaeoarchaean <span class="search-highlight">Moodies</span> <span class="search-highlight">Group</span>, Barberton Greenstone Belt, South Africa
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Journal Article

Tectonic and sedimentary evolution of a potential supra-detachment fault basin, Archaean Moodies Group (~3.22 Ga), central Barberton Greenstone Belt Available to Purchase

A. Zametzer, S. Reimann, C.E. Heubeck, T.B. Thomsen, S.H. Serre
Published: 01 September 2023
South African Journal of Geology (2023) 126 (3): 235–260.
DOI: https://doi.org/10.25131/sajg.126.0016
... preserved in greenstone belts often hinder geological insights. Exceptionally, the largely siliciclastic Palaeoarchaean ( ca. 3.22 Ga) Moodies Group, uppermost unit of the Barberton Greenstone Belt (BGB) in South Africa and Eswatini, allows a detailed understanding of regional depositional processes...
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View PDF for article title, Tectonic and sedimentary evolution of a potential supra-detachment fault basin, Archaean <span class="search-highlight">Moodies</span> <span class="search-highlight">Group</span> (~3.22 Ga), central Barberton Greenstone Belt
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Journal Article

Syndepositional hydrothermalism selectively preserves records of one of the earliest benthic ecosystems, Moodies Group (3.22 Ga), Barberton Greenstone Belt, South Africa Available to Purchase

S. Reimann, C.E. Heubeck, P. Fugmann, D.J. Janse van Rensburg, A. Zametzer, S.H. Serre, T.B. Thomsen
Published: 01 March 2021
South African Journal of Geology (2021) 124 (1): 253–278.
DOI: https://doi.org/10.25131/sajg.124.0012
...S. Reimann; C.E. Heubeck; P. Fugmann; D.J. Janse van Rensburg; A. Zametzer; S.H. Serre; T.B. Thomsen Abstract The ~3.22 Ga Moodies Group, Barberton Greenstone Belt (BGB), South Africa, provides a unique window into Archaean sedimentary, magmatic and ecological processes. In the central BGB...
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View PDF for article title, Syndepositional hydrothermalism selectively preserves records of one of the earliest benthic ecosystems, <span class="search-highlight">Moodies</span> <span class="search-highlight">Group</span> (3.22 Ga), Barberton Greenstone Belt, South Africa
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Journal Article

Microbial-mat-associated tephra of the Archean Moodies Group, Barberton Greenstone Belt (BGB), South Africa: Resemblance to potential biostructures and ecological implications Available to Purchase

I. Köhler, C. Heubeck
Published: 01 June 2019
South African Journal of Geology (2019) 122 (2): 221–236.
DOI: https://doi.org/10.25131/sajg.122.0015
... of putative microfossils dating back as far as 3700 Ma have been described, the syngeneity and biogenicity of many occurrences is debated, and some of the proposed fossils have been found to be either contaminants or abiotic artefacts. The ~3200 Ma Moodies Group of the Barberton Greenstone Belt (BGB), South...
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View PDF for article title, Microbial-mat-associated tephra of the Archean <span class="search-highlight">Moodies</span> <span class="search-highlight">Group</span>, Barberton Greenstone Belt (BGB), South Africa: Resemblance to potential biostructures and ecological implications
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Journal Article

The Lomati Delta Complex: A prograding tidal delta in the Archean Moodies Group, Barberton Greenstone Belt Available to Purchase

L. Stutenbecker, C. Heubeck, A. Zeh
Published: 01 March 2019
South African Journal of Geology (2019) 122 (1): 17–38.
DOI: https://doi.org/10.25131/sajg.122.0002
..., and age dating of the Lomati Delta Complex, a morphologically prominent, wedge-shaped and dominantly arenaceous unit in the middle Moodies Group (~3.22 Ga) of the central Barberton Greenstone Belt (BGB). Subvertical regional bedding allows cross-sectional correlation within a prograding delta complex from...
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View PDF for article title, The Lomati Delta Complex: A prograding tidal delta in the Archean <span class="search-highlight">Moodies</span> <span class="search-highlight">Group</span>, Barberton Greenstone Belt
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Book Chapter

Composition and Microfacies of Archean Microbial Mats (Moodies Group, ca. 3.22 Ga, South Africa) Available to Purchase

Author(s)
Antonia Gamper, Christoph Heubeck, Dieter Demske, Marek Hoehse
Book: Microbial Mats in Siliciclastic Depositional Systems Through Time
Series: SEPM Special Publication
Publisher: SEPM Society for Sedimentary Geology
Published: 01 January 2012
DOI: 10.2110/sepmsp.101.065
EISBN: 9781565763142
...Introduction Regional Geologyand Depositional Setting of the Moodies Group Fig. 1. Geological sketch map of the Barberton Greenstone Belt (modified after de Ronde and de Wit 1994 ). Moodies Group strata occur in large synclines. The study area is located on the overturned southeastern...
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Abstract
View PDF for content titled, Composition and Microfacies of Archean Microbial Mats (<span class="search-highlight">Moodies</span> <span class="search-highlight">Group</span>, ca. 3.22 Ga, South Africa)
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Abstract The Middle Archean Moodies Group (ca. 3.22 Ga), Barberton Greenstone Belt, South Africa, exposes one of the world’s oldest ecosystems. It includes kerogen-rich laminae and thin chert bands interbedded with coarse-grained and gravelly sandstones. The strata record a medium-energy, tidal coastal environment. Analyses of the microscopic structure and chemical composition of the chert bands through petrographic microscopy, Raman microspectroscopy, laser-induced breakdown spectroscopy (LIBS) analyses, C isotopes, and scanning electron microscope (SEM) photography of macerated material, supported by textural observations of hand samples, suggest that these laminae represent variably compressed and early-silicified microbial mats. Internal wavy laminations, amorphous carbon composition, and negative δ 13 C values strongly imply a biogenic origin. Complete HF maceration of chert bands revealed polygonal cell structures in a formerly extracellular polymeric substance matrix. The tuft- and dome-micromorphology of the laminations resembles that of recent photosynthetic filament-dominated microbial mats. Facies interpretations indicate that microbial mats extensively colonized subtidal to intertidal Archean siliciclastic coastlines.

Journal Article

An early ecosystem of Archean tidal microbial mats (Moodies Group, South Africa, ca. 3.2 Ga) Available to Purchase

Christoph Heubeck
Journal: Geology
Published: 01 October 2009
Geology (2009) 37 (10): 931–934.
DOI: https://doi.org/10.1130/G30101A.1
...Christoph Heubeck Abstract Abundant microbial mats from the Mesoarchean Moodies Group (Barberton Greenstone Belt, South Africa, ca. 3.2 Ga) are densely interbedded with coarse-grained and gravelly sandstones in a nearly mud-free setting. They apparently grew in marginal marine and possibly...
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View PDF for article title, An early ecosystem of Archean tidal microbial mats (<span class="search-highlight">Moodies</span> <span class="search-highlight">Group</span>, South Africa, ca. 3.2 Ga)
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Journal Article

A new window into Early Archean life: Microbial mats in Earth's oldest siliciclastic tidal deposits (3.2 Ga Moodies Group, South Africa) Available to Purchase

Nora Noffke, Kenneth A. Eriksson, Robert M. Hazen, Edward L. Simpson
Journal: Geology
Published: 01 April 2006
Geology (2006) 34 (4): 253–256.
DOI: https://doi.org/10.1130/G22246.1
...Nora Noffke; Kenneth A. Eriksson; Robert M. Hazen; Edward L. Simpson Abstract Newly discovered sedimentary structures produced by ancient microbial mats in Early Archean sandstones of the 3.2 Ga Moodies Group, South Africa, differ fundamentally in appearance and genesis from Early Archean...
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View PDF for article title, A new window into Early Archean life: Microbial mats in Earth&#x27;s oldest siliciclastic tidal deposits (3.2 Ga <span class="search-highlight">Moodies</span> <span class="search-highlight">Group</span>, South Africa)
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Journal Article

Quantifying the oldest tidal record: The 3.2 Ga Moodies Group, Barberton Greenstone Belt, South Africa: Comment and Reply: COMMENT Available to Purchase

Rajat Mazumder
Journal: Geology
Published: 01 December 2001
Geology (2001) 29 (12): 1159.
DOI: https://doi.org/10.1130/0091-7613(2001)029<1159:QTOTRT>2.0.CO;2
... the oldest tidal record: The 3.2 Ga Moodies Group, Barberton Greenstone Belt, South Africa : Geology , v. 28 p. 831 – 834 . Kvale , E.P. , Johnson , H.W. , Sonett , C.P. , Archer , A.W. , and Zawistosky , A. , 1999 , Calculating lunar retreat rates using tidal rhythmites : v...
View PDF for article title, Quantifying the oldest tidal record: The 3.2 Ga <span class="search-highlight">Moodies</span> <span class="search-highlight">Group</span>, Barberton Greenstone Belt, South Africa: Comment and Reply: COMMENT
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Journal Article

Quantifying the oldest tidal record: The 3.2 Ga Moodies Group, Barberton Greenstone Belt, South Africa Available to Purchase

Kenneth A. Eriksson, Edward L. Simpson
Journal: Geology
Published: 01 September 2000
Geology (2000) 28 (9): 831–834.
DOI: https://doi.org/10.1130/0091-7613(2000)28<831:QTOTRT>2.0.CO;2
...Kenneth A. Eriksson; Edward L. Simpson Abstract The 3.2 Ga Moodies Group in the Barberton Greenstone Belt, South Africa, contains the oldest preserved record of tides. The tidal record is preserved in a tidal sand-wave deposit in the lower Moodies Group as bundles of sandstone foresets separated...
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Book Chapter

Sedimentary petrography and provenance of the Archean Moodies Group, Barberton Greenstone Belt Available to Purchase

Author(s)
Christoph Heubeck, Donald R. Lowe
Book: Geologic Evolution of the Barberton Greenstone Belt, South Africa
Publisher: Geological Society of America
Published: 01 March 1999
DOI: 10.1130/0-8137-2329-9.259
Abstract
View PDF for content titled, Sedimentary petrography and provenance of the Archean <span class="search-highlight">Moodies</span> <span class="search-highlight">Group</span>, Barberton Greenstone Belt
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Image
Representative outcrop photographs of Moodies Group lithologies and sedimentary structures in the central BGB. (A) View from Shokohlwa Mountain northeastward along strike of the southeastern limb of the Saddleback Syncline. All beds dip steeply to the right and young to the left (cp. Figure 4A). They consist of thick- to medium-bedded, in places gravelly and commonly microbially laminated silicified sandstones. (B) Rippled, silicified and FeOx-altered sandstone. The Heights Syncline. (C) Gravelly, cross-bedded, silicified sandstone. Saddleback Syncline. (D) Mudcracked shale coating on bedding plane. Saddleback Syncline.

Representative outcrop photographs of Moodies Group lithologies and sedimen... Available to Purchase

Published: 01 March 2021
Figure 2. Representative outcrop photographs of Moodies Group lithologies and sedimentary structures in the central BGB. ( A ) View from Shokohlwa Mountain northeastward along strike of the southeastern limb of the Saddleback Syncline. All beds dip steeply to the right and young to the left (cp
Image
Microbially laminated quartzose Moodies Group sandstone in outcrop and thin section, illustrating preservation of fine detail and a lack of compaction. Stratigraphic younging is to the top. (A) to (D) from the Saddleback Syncline (north of the Inyoka Fault zone). (E) is from the The Heights Syncline, (F) is from the Masenjane Homocline, both south of the Inyoka Fault zone. (A) Undulatory, domed, tufted kerogenous mats. Black-chert-filled cavities are interpreted as early-diagenetic gas bubbles formed shortly after surficial sealing (Homann et al., 2016). (B) Microbial mat-chip conglomerate, showing rigid and firm microbial-mat shreds in a shallow and wide tidal channel. (C) Slumped tidal-channel margin, showing tilted, apparently surficially stiffened bed of gravel, sand, and microbial mats in a tilted position. Tidal channel is to the left. (D) Thin-section photomicrograph, showing “floating” fine-grained quartz grains in dark kerogenous matrix (sample 08-848, parallel nicols). (E) Fenestral porosity in horizontally bedded sandstone, with fluid-escape structure; these are observed only in Moodies Group microbially laminated sandstone. Originally carbonate-cemented microbial mats have been leached, resulting in a fenestral porosity. This is a common facies in hydrothermally altered Moodies Group sandstone south of the Inyoka Fault zone. (F) Sawed hand sample (17-142) of microbially laminated sandstone from the Masenjane Homocline, within the region of mafic stockwork dykes. Coin for scale.

Microbially laminated quartzose Moodies Group sandstone in outcrop and thin... Available to Purchase

Published: 01 March 2021
Figure 3. Microbially laminated quartzose Moodies Group sandstone in outcrop and thin section, illustrating preservation of fine detail and a lack of compaction. Stratigraphic younging is to the top. (A) to (D) from the Saddleback Syncline (north of the Inyoka Fault zone). (E) is from
Image
Schematic relationship of the Lomati River Sill to the Moodies Group (legend as in Figure 4). The hydrothermal halo around the sills preserved microbial mats in Moodies Group sandstones but preservation south of the Inyoka Fault zone was largely compromised by subsequent faulting and stockwork dyke intrusions.

Schematic relationship of the Lomati River Sill to the Moodies Group (legen... Available to Purchase

Published: 01 March 2021
Figure 5. Schematic relationship of the Lomati River Sill to the Moodies Group (legend as in Figure 4 ). The hydrothermal halo around the sills preserved microbial mats in Moodies Group sandstones but preservation south of the Inyoka Fault zone was largely compromised by subsequent faulting
Image
Aspects of sericitic alteration in Moodies Group sandstones in the central BGB. (A) Photomicrograph of highly birefringent pyrophyllitic and sericitic pseudomatrix grain with large muscovite laths, probably resulting from feldspar breakdown (sample SR17-09A, crossed nicols). (B) μ-XRF element maps of a matrix-rich, medium-grained Moodies Group sandstone. Right: Al (magenta), K (orange) represent the sericitic matrix, Si (black) represents quartz. Left: Ti (violet) occurs in rutile and anatase. Fe (red) is represented by hematite and alumohematite. Euhedral Fe domains largely consist of accessory pyrite (sample SR17-09A). (C) Electron-backscatter image of altered grain composed of sericite (white, loc. 2-4) and chlorite (grey, loc. 2-3) within a silica-cement-dominated matrix (sample 15*068). (D) Electron-backscatter image showing heterogeneous FeOx-altered matrix. Monocrystalline quartz and chert (Qz), both light grey, represent the major framework grains. The matrix is dominated by muscovite (Mc), hematite (Hem) and chamosite (Cha, sample SR17-03). (E) Representative Raman spectra and microprobe analyses of sericite (pyrophyllite) and chlorite (chamosite), respectively; locations cp. Figure 11D. First-order polynomial baseline correction was applied to measured Raman spectra to reduce the effect of fluorescence. Both spectra are compared to the reference spectra of RRUFF database (R070728 and R050051).

Aspects of sericitic alteration in Moodies Group sandstones in the central ... Available to Purchase

Published: 01 March 2021
Figure 11. Aspects of sericitic alteration in Moodies Group sandstones in the central BGB. ( A ) Photomicrograph of highly birefringent pyrophyllitic and sericitic pseudomatrix grain with large muscovite laths, probably resulting from feldspar breakdown (sample SR17-09A, crossed nicols). ( B ) μ
Image
Aspects of FeOx-altered Moodies Group sandstone at outcrop scale. (A) and (C) from the Maid-of-the-Mists Syncline, (B) and (D) from the The Heights Syncline. (A) FeOx-altered sandstone boulders crosscut by quartz veins. This rock type weathers to crumbly red soil. (B) Quartz microveins in FeOx-altered sandstone. (C) FeOx veins in silicified sandstone. (D) Liesegang rings in Moodies Group sandstone, common near mafic dykes. Recent weathering creates cavities in which redox reactions with percolating acidic fluids has dissolved carbonate cement. Subrecent botryoidal hematite is common in the cavities.

Aspects of FeOx-altered Moodies Group sandstone at outcrop scale. (A) and (... Available to Purchase

Published: 01 March 2021
Figure 12. Aspects of FeOx-altered Moodies Group sandstone at outcrop scale. (A) and (C) from the Maid-of-the-Mists Syncline, (B) and (D) from the The Heights Syncline. ( A ) FeOx-altered sandstone boulders crosscut by quartz veins. This rock type weathers to crumbly red soil. ( B ) Quartz
Image
Field photographs of silicified and fractured Moodies Group sandstone. (A) Densely spaced, randomly oriented fractured and quartz-filled veins are typical in “fractured-facies” sandstone outcrops of MMS. Bedding is largely obliterated. Hammer for scale. (B) Fractured quartz veins cross-cutting conglomerate, midsection of the southern slope of MMS. Hammer for scale. (C) Silicified fractured and brecciated sandstone in outcrop. Angle Station Syncline, ca. 250 m south of Inyoka Fault zone. R40 road is visible in the right middle ground. (D) Closeup of rock surface from the same outcrop. Coin for scale. (E) Fractured sandstone clast of quartz sandstone in quartzose matrix, illustrating early silicification, fracturing, and reworking of some Moodies strata.

Field photographs of silicified and fractured Moodies Group sandstone. ( A ... Available to Purchase

Published: 01 March 2021
Figure 16. Field photographs of silicified and fractured Moodies Group sandstone. ( A ) Densely spaced, randomly oriented fractured and quartz-filled veins are typical in “fractured-facies” sandstone outcrops of MMS. Bedding is largely obliterated. Hammer for scale. ( B ) Fractured quartz veins
Image
Diagenetic-sequence diagram of Moodies Group sandstone (from Heubeck, 2019), modified to emphasize alteration processes.

Diagenetic-sequence diagram of Moodies Group sandstone (from Heubeck, 2019... Available to Purchase

Published: 01 March 2021
Figure 17. Diagenetic-sequence diagram of Moodies Group sandstone (from Heubeck, 2019 ), modified to emphasize alteration processes.
Image
Undeformed polymictic basal conglomerate of the Moodies Group on the southern limb of the Eureka Syncline (2.7 km east of Sheba GM in Sheba Creek), showing a variety of pebble types, including granitoid pebbles (centre of photograph), which were found to range in age between ca. 3460 and 3570 Ma (Kröner and Compston, 1988; Sanchez-Garrido et al., 2011; Kröner et al., 2018). Drillhole (black dot) to the left of top centre has a diameter of 30 mm.

Undeformed polymictic basal conglomerate of the Moodies Group on the southe... Available to Purchase

Published: 01 December 2019
Figure 3. Undeformed polymictic basal conglomerate of the Moodies Group on the southern limb of the Eureka Syncline (2.7 km east of Sheba GM in Sheba Creek), showing a variety of pebble types, including granitoid pebbles (centre of photograph), which were found to range in age between ca. 3460
Image
(A) Deformed conglomerate in the Moodies Group and (B) flattened volcaniclastic fragments in the Schoongezicht Formation (Fig Tree Group) underlying the Moodies basal conglomerate in the Ezzy’s Pass road cutting on the northern rim of the Eureka Syncline. The long axes of the pebbles and volcaniclastic fragments plunge subvertically. (C) Tight folds resulting from intense flattening of Fig Tree Group ferruginous shales, cherts and greywackes in the Lily GM. All examples shown are directly south of the Lily West Syncline (Figure 12) which formed during an early D2 deformation event. The deformed rocks shown are all related to flattening caused by the intrusion of the Stentor Pluton. (width of photographs A, B, C, ca. 70 cm).

( A ) Deformed conglomerate in the Moodies Group and ( B ) flattened volcan... Available to Purchase

Published: 01 December 2019
Figure 10. ( A ) Deformed conglomerate in the Moodies Group and ( B ) flattened volcaniclastic fragments in the Schoongezicht Formation (Fig Tree Group) underlying the Moodies basal conglomerate in the Ezzy’s Pass road cutting on the northern rim of the Eureka Syncline. The long axes