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Buck Reef Chert

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(A–B) Thin sections from Buck Reef Chert samples. Optical images (A) of the bedded chert (H21) and (B) of the vein chert H24. (C) Average Raman spectra of carbonaceous material.

(A–B) Thin sections from Buck Reef Chert samples. Optical images ( A ) of t... Available to Purchase

Published: 01 December 2013
Figure 10 (A–B) Thin sections from Buck Reef Chert samples. Optical images ( A ) of the bedded chert (H21) and ( B ) of the vein chert H24. ( C ) Average Raman spectra of carbonaceous material.
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Figure 1. Measured section through Buck Reef Chert (Tice and Lowe, 2004) with representative whole-rock rare earth element (REE) abundances (normalized to post- archean average shale) and authigenic uranium (± estimated error). La (leftmost) point is aligned with sample height. REE scale illustrates relative abundances within individual distributions. Base of section is sandstone representing coastal system. Lowest 15 m of section is evaporite facies; 15–180 m of section is mostly shallow to deep shelf facies; 180–235 m of section is basin facies. Elemental abundances determined by inductively coupled plasma–mass spectrometry at Washington State University Geoanalytical Laboratory (Pullman, Washington).

Figure 1. Measured section through Buck Reef Chert ( Tice and Lowe, 2004 ) ... Available to Purchase

Published: 01 January 2006
Figure 1. Measured section through Buck Reef Chert ( Tice and Lowe, 2004 ) with representative whole-rock rare earth element (REE) abundances (normalized to post- archean average shale) and authigenic uranium (± estimated error). La (leftmost) point is aligned with sample height. REE scale
Journal Article

Hydrogen-based carbon fixation in the earliest known photosynthetic organisms Available to Purchase

Michael M. Tice, Donald R. Lowe
Journal: Geology
Published: 01 January 2006
Geology (2006) 34 (1): 37–40.
DOI: https://doi.org/10.1130/G22012.1
...Figure 1. Measured section through Buck Reef Chert ( Tice and Lowe, 2004 ) with representative whole-rock rare earth element (REE) abundances (normalized to post- archean average shale) and authigenic uranium (± estimated error). La (leftmost) point is aligned with sample height. REE scale...
FIGURES
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Principal biogenic and chemical sedimentary rock types in distal facies of the Onverwacht Group. (A) Black-and-white banded chert from thin layer in the lower part of the Hooggenoeg Formation. Like all black-and-white banded chert units, this one is composed of alternating bands of carbonaceous chert (black) and translucent chert (gray) less than 10 cm thick. Hooggenoeg Formation (H2v). (B) Black-and-white banded chert from the lower Buck Reef Chert. Kromberg Formation (K1c). (C) Black-and-white banded chert showing early brittle fracture and bending of the white chert bands within a soft matrix of black carbonaceous sediment. Kromberg Formation, Buck Reef Chert (K1c). (D) Layers of massive black chert without regular banding. Mendon Formation. (E) Banded ferruginous chert composed initially of bands of chert (white) and siderite (red), but the siderite is now oxidized to iron oxides. Banded ferruginous chert lacks current structures. Kromberg Formation, Buck Reef Chert (K1c, middle part).

Principal biogenic and chemical sedimentary rock types in distal facies of ... Open Access

Published: 03 July 2024
of carbonaceous chert (black) and translucent chert (gray) less than 10 cm thick. Hooggenoeg Formation (H2v). (B) Black-and-white banded chert from the lower Buck Reef Chert. Kromberg Formation (K1c). (C) Black-and-white banded chert showing early brittle fracture and bending of the white chert bands within
Journal Article

Gliding and overthrust nappe tectonics of the Barberton Greenstone Belt revisited: A review of deformation styles and processes Available to Purchase

M.J. Van Kranendonk
Published: 01 March 2021
South African Journal of Geology (2021) 124 (1): 181–210.
DOI: https://doi.org/10.25131/sajg.124.0017
... that, combined with fractionation of mafic magma chambers produced widespread felsic magmatism at 3 470 to 3 410 Ma (upper Hooggenoeg Formation and Buck Reef Chert), the latter parts of which were accompanied by the formation of D1 dome-and-keel structures via PCO in deeper-levels of the crust represented...
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View PDF for article title, Gliding and overthrust nappe tectonics of the Barberton Greenstone Belt revisited: A review of deformation styles and processes
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Comparison of average Raman spectra of carbonaceous matter from various bedded cherts: H2, Hooggenoeg Formation; H21, Buck Reef Chert; O9, Kromberg Formation; M3, Mendon Formation.

Comparison of average Raman spectra of carbonaceous matter from various bed... Available to Purchase

Published: 01 December 2013
Figure 12 Comparison of average Raman spectra of carbonaceous matter from various bedded cherts: H2, Hooggenoeg Formation; H21, Buck Reef Chert; O9, Kromberg Formation; M3, Mendon Formation.
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Layers of silica granules at different scales. (A–C) Black-and-white banded chert: (A) outcrop photo, Buck Reef Chert (locality Buck Reef Chert), (B) polished slab of white chert band showing faintly granular texture, upper Mendon Formation (locality BH-03), and (C) thin section of silica granules from a white chert band, upper Mendon Formation (locality SAF 521). (D–F) Lenticular granular layers within ferruginous shale, lower Mapepe Formation (locality SAF 183): (D) polished slab with lenses of two distinct granule types (arrows), both shown in thin section—a lower lens of minimally compacted, slightly ferruginous granules (E) and an upper lens of more compacted non-ferruginous granules (F). (G–I) Banded iron formation, lower Mapepe Formation: (G) outcrop photo showing chert bands (arrows) within jasper, (H) core photo highlighting ∼1-cm-thick granular layer within banded iron formation (dashed outline) (sample SAF 649–14), and (I) thin-section image of pure silica granules within slightly ferruginous matrix from the layer shown in H. See supplementary Table DR1 for additional stratigraphic information for samples shown and supplementary Figure DR1 for map of sample localities (see text footnote 1).

Layers of silica granules at different scales. (A–C) Black-and-white banded... Available to Purchase

Published: 01 July 2015
Figure 1. Layers of silica granules at different scales. (A–C) Black-and-white banded chert: (A) outcrop photo, Buck Reef Chert (locality Buck Reef Chert), (B) polished slab of white chert band showing faintly granular texture, upper Mendon Formation (locality BH-03), and (C) thin section
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Outcrop (A) and thin-section (B–G) images of representative occurrences of silica granules associated with black-and-white banded chert and black chert. (A) Outcrop photo of white chert plate breccia, Buck Reef Chert (locality Buck Reef Chert). (B) Sharp contact between silica granule layer (white chert band) and adjacent detrital organic layer (black chert band), upper Mendon Formation (locality SAF 521). (C) Silica granules mixed with finer-grained detrital organic grains, lower Mapepe Formation (locality BHR-02). (D) Large silica granules associated with a variety of organic and volcanic grain types, upper Mendon Formation (locality SAF 521). (E) Silica granule intraclast within an intraclast breccia, upper Mendon Formation (locality SAF 186). (F) Silica granules, intraclasts, detrital organic grains, and volcanic grains within an intraclast breccia bed from the same sample as E, upper Mendon Formation (locality SAF 186). (G) Organic grains and silica granules from a black chert, upper Mendon Formation (locality CQ-01). Silica granules (arrows) occur within the bed and at the base of the overlying graded bed. These granules are similar in size to and in some cases slightly coarser than the associated detrital organic grains. See supplementary Table DR1 for additional stratigraphic information for samples shown and supplementary Figure DR1 for map of sample localities (see text footnote 1).

Outcrop (A) and thin-section (B–G) images of representative occurrences of ... Available to Purchase

Published: 01 July 2015
Figure 3. Outcrop (A) and thin-section (B–G) images of representative occurrences of silica granules associated with black-and-white banded chert and black chert. (A) Outcrop photo of white chert plate breccia, Buck Reef Chert (locality Buck Reef Chert). (B) Sharp contact between silica granule
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Emblematic Archean and Proterozoic chert formations. A–Landscape view of the Dresser Formation at the North Pole locality and the outcrops of (B) stromatolitic chert, and (C) stromatolitic and bedded cherts. D–Landscape view of the Buck Reef Chert with (E) white and black bedded chert, and (F) evaporitic chert. G–Outcrops of the Mendon chert with laminated black and white cherts (H and I). J–Kakabeka Falls, Ontario in Canada, a locality for the Gunflint Formation. (K) Schreiber Beach locality with outcrops of stromatolitic chert. (L) A detailed view of the Schreiber Beach stromatolitic chert. Photographs are courtesy of N. Olivier, P. Sans-Jofre, C. Thomazo and R. Shapiro.

Emblematic Archean and Proterozoic chert formations. A –Landscape view of ... Available to Purchase

Published: 01 January 2021
Figure 3. Emblematic Archean and Proterozoic chert formations. A –Landscape view of the Dresser Formation at the North Pole locality and the outcrops of ( B ) stromatolitic chert, and ( C ) stromatolitic and bedded cherts. D –Landscape view of the Buck Reef Chert with ( E ) white and black
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Figure 10. Comparison of the δ18O values of the least metamorphosed Buck Reef cherts on the west limb of the Onverwacht Anticline with their highly metamorphosed equivalents on the east limb of the anticline. The similar values indicate that the δ18O values were preserved during high-grade metamorphism and imply that W/R ratios were very low.

Figure 10. Comparison of the δ 18 O values of the least metamorphosed Buck ... Available to Purchase

Published: 01 May 2003
Figure 10. Comparison of the δ 18 O values of the least metamorphosed Buck Reef cherts on the west limb of the Onverwacht Anticline with their highly metamorphosed equivalents on the east limb of the anticline. The similar values indicate that the δ 18 O values were preserved during high-grade
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Figure 4. Range of D positions observed in samples by unit. Placement of prehnite-pumpellyite line is uncertain. Temperature is unlikely to be linear in this scale. MM—Middle Marker; 1AMM—First chert above Middle Marker; BRC—Buck Reef Chert; other units as in Figure 1. Mine samples from Fig Tree Group are labeled Sheba and Princeton after mines from which they were collected. Number of samples analyzed from each unit is noted above or below bar. If no number is indicated, then only one sample was analyzed

Figure 4. Range of D positions observed in samples by unit. Placement of pr... Available to Purchase

Published: 01 January 2004
Figure 4. Range of D positions observed in samples by unit. Placement of prehnite-pumpellyite line is uncertain. Temperature is unlikely to be linear in this scale. MM—Middle Marker; 1AMM—First chert above Middle Marker; BRC—Buck Reef Chert; other units as in Figure 1 . Mine samples from Fig Tree
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Schematic cross section of rocks of the uppermost Komati Formation through the Mendon Formation on the west limb of the Onverwacht anticline (Fig. 1). Unit thicknesses have been held constant at the thicknesses in Hooggenoeg valley near the center of the figure. The diagram shows the principal lithofacies in the upper Onverwacht Group: white—basaltic volcanic units; green—basaltic to komatiitic lapillistone; purple—komatiitic volcanic units; orange—felsic volcanic and volcaniclastic units. White arrow indicates the large explosion crater filled with lapillistone in the top of the Buck Reef Chert.

Schematic cross section of rocks of the uppermost Komati Formation through ... Open Access

Published: 03 July 2024
Reef Chert.
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Chondrite-normalized REE plots (BBC, black banded chert; BVC, black vein chert). (A) Cherts from the Middle Marker in comparison with a sample of silicified komatiitic basalt 1 m below the chert horizon. (B) Cherts from horizon H3c of the Hooggenoeg Formation in comparison with a sample of silicified basalt 1 m below the chert horizon. (C) Bedded chert of horizon H5c, vein chert below the chert horizon, and silicified basalt 1.5 m below H5c. (D) Bedded and vein chert of the Buck Reef Chert, silicified shale of stratigraphic unit H6, and chert of K1c1 of the Kromberg Formation; average composition of the Theespruit pluton is shown for comparison. (E) Bedded and vein chert from two localities of chert horizon K3c at the top of the Kromberg Formation; silicified basalts below the chert horizons is shown for comparison. (F) Bedded and vein chert from different localities at the top of the Mendon Formation; a sample of Fig Tree shale taken above the chert horizon is shown for comparison.

Chondrite-normalized REE plots (BBC, black banded chert; BVC, black vein ch... Available to Purchase

Published: 01 December 2013
with a sample of silicified basalt 1 m below the chert horizon. ( C ) Bedded chert of horizon H5c, vein chert below the chert horizon, and silicified basalt 1.5 m below H5c. ( D ) Bedded and vein chert of the Buck Reef Chert, silicified shale of stratigraphic unit H6, and chert of K1c1 of the Kromberg Formation
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Figure 2. Dominance diagrams for species of uranium. A: pCO2 = 0.04 atm. B: pCO2 = 5 atm. Diagrams were calculated for total dissolved uranium of 10 nM using commercially available software. Shaded areas show stability fields for siderite (light) and ferric hydroxide (dark) for total dissolved iron of 50 μM. Dash-dot lines show maximum deep-marine pH such that total marine CO2 does not exceed estimated modern crustal CO2 inventory of 60–80 atm (Grotzinger and Kasting, 1993; Kasting, 1993). T = 70 °C. Filled circles connected by short lines show states of shallow water (low pH) and deep water (high pH) that could produce Buck Reef Chert authigenic uranium and siderite distributions.

Figure 2. Dominance diagrams for species of uranium. A: p CO 2 = 0.04 atm... Available to Purchase

Published: 01 January 2006
) and deep water (high pH) that could produce Buck Reef Chert authigenic uranium and siderite distributions.
Journal Article

Onverwacht Group, Barberton Greenstone Belt, South Africa: 300 m.y. development of a Paleoarchean stagnant lid Open Access

Donald R. Lowe
Journal: GSA Bulletin
Published: 03 July 2024
GSA Bulletin (2025) 137 (1-2): 259–278.
DOI: https://doi.org/10.1130/B37573.1
... of carbonaceous chert (black) and translucent chert (gray) less than 10 cm thick. Hooggenoeg Formation (H2v). (B) Black-and-white banded chert from the lower Buck Reef Chert. Kromberg Formation (K1c). (C) Black-and-white banded chert showing early brittle fracture and bending of the white chert bands within...
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View PDF for article title, Onverwacht Group, Barberton Greenstone Belt, South Africa: 300 m.y. development of a Paleoarchean stagnant lid
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Ironstone bodies of the Barberton greenstone belt, South Africa: Products of a Cenozoic hydrological system, not Archean hydrothermal vents! Available to Purchase

Donald R. Lowe, Gary R. Byerly
Journal: GSA Bulletin
Published: 01 January 2007
GSA Bulletin (2007) 119 (1-2): 65–87.
DOI: https://doi.org/10.1130/B25997.1
... quartz disseminated within a goethite matrix (Fig. 5E) . Four specific areas are described here (Fig. 7B) : (1) ironstone units within in situ Buck Reef Chert at an elevation of 1560–1580 m at the upslope end of a large landslide (locality A, Fig. 7B ), (2) a small ironstone mass at the edge...
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View PDF for article title, Ironstone bodies of the Barberton greenstone belt, South Africa: Products of a Cenozoic hydrological system, not Archean hydrothermal vents!
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Sedimentology and geochemistry of Archean silica granules Available to Purchase

Elizabeth J.T. Stefurak, Donald R. Lowe, Danielle Zentner, Woodward W. Fischer
Journal: GSA Bulletin
Published: 01 July 2015
GSA Bulletin (2015) 127 (7-8): 1090–1107.
DOI: https://doi.org/10.1130/B31181.1
...Figure 1. Layers of silica granules at different scales. (A–C) Black-and-white banded chert: (A) outcrop photo, Buck Reef Chert (locality Buck Reef Chert), (B) polished slab of white chert band showing faintly granular texture, upper Mendon Formation (locality BH-03), and (C) thin section...
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View PDF for article title, Sedimentology and geochemistry of Archean silica granules
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Journal Article

CHERTS OF THE BARBERTON GREENSTONE BELT, SOUTH AFRICA: PETROLOGY AND TRACE-ELEMENT GEOCHEMISTRY OF 3.5 TO 3.3 GA OLD SILICIFIED VOLCANICLASTIC SEDIMENTS Available to Purchase

A. HOFMANN, R. BOLHAR, B. ORBERGER, F. FOUCHER
Published: 01 December 2013
South African Journal of Geology (2013) 116 (2): 297–322.
DOI: https://doi.org/10.2113/gssajg.116.2.297
...Figure 10 (A–B) Thin sections from Buck Reef Chert samples. Optical images ( A ) of the bedded chert (H21) and ( B ) of the vein chert H24. ( C ) Average Raman spectra of carbonaceous material. ...
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View PDF for article title, <span class="search-highlight">CHERTS</span> OF THE BARBERTON GREENSTONE BELT, SOUTH AFRICA: PETROLOGY AND TRACE-ELEMENT GEOCHEMISTRY OF 3.5 TO 3.3 GA OLD SILICIFIED VOLCANICLASTIC SEDIMENTS
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Journal Article

Thermal history of the 3.5–3.2 Ga Onverwacht and Fig Tree Groups, Barberton greenstone belt, South Africa, inferred by Raman microspectroscopy of carbonaceous material Available to Purchase

Michael M. Tice, Benjamin C. Bostick, Donald R. Lowe
Journal: Geology
Published: 01 January 2004
Geology (2004) 32 (1): 37–40.
DOI: https://doi.org/10.1130/G19915.1
...Figure 4. Range of D positions observed in samples by unit. Placement of prehnite-pumpellyite line is uncertain. Temperature is unlikely to be linear in this scale. MM—Middle Marker; 1AMM—First chert above Middle Marker; BRC—Buck Reef Chert; other units as in Figure 1 . Mine samples from Fig Tree...
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View PDF for article title, Thermal history of the 3.5–3.2 Ga Onverwacht and Fig Tree Groups, Barberton greenstone belt, South Africa, inferred by Raman microspectroscopy of carbonaceous material
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Silica botryoids from chemically oscillating reactions and as Precambrian environmental proxies Available to Purchase

Shahab Varkouhi, Dominic Papineau
Journal: Geology
Published: 19 May 2023
Geology (2023) 51 (7): 683–687.
DOI: https://doi.org/10.1130/G50948.1
... depleted 34 S, which are among the earliest chemical biosignatures ( Roerdink et al., 2013 ). Below the Mendon Formation, the ~350-m-thick Buck Reef Chert marks the stratigraphic transition from the banded chert base of the Kromberg Formation to the underlying mainly basaltic Hooggenoeg Formation...
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