Geodynamic interpretation of the Cape and Karoo basins, South Africa

Tankard, A. J.; Welsink, H. J.; Aukes, Peter; Newton, Robert J.; Stettler, E.H.

doi:10.1016/b978-0-444-56357-6.00022-6

Cited by 33 publications

(27 citation statements)

References 125 publications

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“…These features suggest that the subsidence of the southern Kaapvaal craton may not be intrinsically driven, but instead extrinsic, that is, by flexural loading from nearby subduction (cf. Tankard et al, 2012). This inference is also consistent with the high Mg# of mantle xenoliths entrained in kimberlites which were erupted after the basin subsidence (Griffin et al, 2014).…”

Section: Implication For Other Cratons With Sedimentary Basinssupporting

confidence: 75%

“…Some cratons like the Kaapvaal Craton, though accepting sediments, are not at the center of subsidence. The sedimentation thins towards the interior of the Kaapvaal craton and thickens towards the adjacent orogenic belt (Tankard et al, 2012) (Figures 2 and 6). These features suggest that the subsidence of the southern Kaapvaal craton may not be intrinsically driven, but instead extrinsic, that is, by flexural loading from nearby subduction (cf.…”

Section: Implication For Other Cratons With Sedimentary Basinsmentioning

confidence: 99%

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Development of a Dense Cratonic Keel Prior to the Destruction of the North China Craton: Constraints From Sedimentary Records and Numerical Simulation

Liu

Xia

et al. 2019

JGR Solid Earth

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It remains unclear why some cratonic lithospheres like the North China Craton (NCC) have undergone significant thinning and catastrophic destruction. Here we provide evidence for a dense Phanerozoic cratonic keel beneath the NCC that provides a reason for the craton destruction during the late Mesozoic. We observed two long‐lasting (>100 Myr) episodes of surface subsidence that formed the saucer‐shaped basin topography on the NCC from the Paleozoic to early Mesozoic, which was not associated with lithosphere stretching or a high sea level. Based on a detailed geological and geochemical analysis and 2‐D numerical experiments, we show that this subsidence most likely reflects the secular cooling and eclogitization of iron‐rich materials infiltrated into the cratonic mantle since the early Phanerozoic, a process that is the most prominent over the eastern NCC. This result implies that the lithosphere beneath the eastern NCC became gravitationally unstable prior to its Mesozoic destruction as its keel became progressively denser during the Paleozoic. An early Mesozoic partial removal of this dense keel possibly led to widespread surface uplift of the NCC, as indicated by regional basin inversion. We conclude that the long‐term subsidence of a cratonic basin reflects a gradual increase of the lithospheric density and that this type of subsidence should not be considered a characteristic of stable cratons as previously assumed.

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Section: Implication For Other Cratons With Sedimentary Basinssupporting

confidence: 75%

Section: Implication For Other Cratons With Sedimentary Basinsmentioning

confidence: 99%

Development of a Dense Cratonic Keel Prior to the Destruction of the North China Craton: Constraints From Sedimentary Records and Numerical Simulation

Liu

Xia

et al. 2019

JGR Solid Earth

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“…, ; Turner ; Tankard et al . , ; Lindeque et al . ), but the most prevalent is the reciprocal‐foreland basin model proposed by Catuneanu et al .…”

Section: Discussionmentioning

confidence: 99%

Vertebrate assemblages from the north-central Main Karoo Basin, South Africa, and their implications for mid-Permian biogeography

Groenewald

Day

Rubidge

2019

LET

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The rich fossil vertebrate record from the Beaufort Group, Main Karoo Basin, provides a global standard for mid‐Permian to Mid‐Triassic continental faunas. However, recent studies have demonstrated variability in the composition of contemporaneous faunas across Gondwana. This raises the question of how much the vertebrate faunas differ within the Karoo, where the taxonomic composition of vertebrate assemblage zones (AZs) is mostly considered to be uniform. Although fossil material is known from across the outcrop of the Beaufort Group, the lowest Beaufort strata have received little attention, particularly north of S31°10′. Here, we report two fossil tetrapod assemblages from the lowest Beaufort Group in the southern Free State Province, which represent the northernmost point at which the lowest Beaufort has been targeted for collecting. The lower assemblage is characterized by an abundance of the small dicynodont Eosimops and can thus be attributed to the Tapinocephalus AZ (Guadalupian), but the absence of dinocephalian or pareiasaurian material is unlike contemporaneous assemblages found further south. This suggests that the Tapinocephalus AZ was not uniform across the entire basin and highlights that the abundance, distribution and taxonomic composition of Karoo biozones may vary more than currently appreciated. The upper assemblage, characterized by the dicynodonts Oudenodon, Aulacephalodon and Dinanomodon, is attributable to the upper Cistecephalus AZ to lower Daptocephalus AZ. The juxtaposition of the lower Tapinocephalus AZ and upper Cistecephalus\lower Daptocephalus AZ in the southern Free State implies a stratigraphic gap from the Middle to Late Permian of up to 6 million years.

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“…These areas of greater subsidence were infilled by progressively lower gradient clinothems as sedimentation outpaced subsidence. The differential subsidence in the early basin fill may have been related to the configuration of pre‐existing basement fault blocks (Tankard et al., ). However, the subsidence responsible for the increased accumulation of sand on the shelf during the later accretion‐dominated phase could also be related to initiation of flexural loading, as the Karoo Basin transitioned into its well documented retro‐arc foreland basin setting (De Wit & Ransome, ; López‐Gamundí & Rossello, ; Veevers et al., ).…”

Section: Discussionmentioning

confidence: 99%

“…The Karoo Basin has traditionally been interpreted as a retro‐arc foreland basin, developed inboard of the Cape Fold Belt, in response to the northward subduction of the Panthalassan (palaeo‐Pacific) plate beneath the Gondwana plate (De Wit & Ransome, ; López‐Gamundí & Rossello, ; Veevers, Cole, & Cowan, ). However, recent radiometric dating (Blewett and Phillips, ) and tectonostratigraphic analyses (Tankard, Welsink, Aukes, Newton, & Stettler, , ) support a Triassic age for the development of the Cape Fold Belt. Subsidence during the Permian pre‐foreland basin stage has been attributed to dynamic topography (mantle flow) associated with the subducting plate, with variable foundering of basement blocks (Pysklywec & Mitrovica, ; Tankard et al., ).…”

Section: Geological Settingmentioning

confidence: 99%

Clinoform architecture and along‐strike facies variability through an exhumed erosional to accretionary basin margin transition

et al. 2019

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Exhumed basin margin‐scale clinothems provide important archives for understanding process interactions and reconstructing the physiography of sedimentary basins. However, studies of coeval shelf through slope to basin‐floor deposits are rarely documented, mainly due to outcrop or subsurface dataset limitations. Unit G from the Laingsburg depocentre (Karoo Basin, South Africa) is a rare example of a complete basin margin scale clinothem (>60 km long, 200 m‐high), with >10 km of depositional strike control, which allows a quasi‐3D study of a preserved shelf‐slope‐basin floor transition over a ca. 1,200 km2 area. Sand‐prone, wave‐influenced topset deposits close to the shelf‐edge rollover zone can be physically mapped down dip for ca. 10 km as they thicken and transition into heterolithic foreset/slope deposits. These deposits progressively fine and thin over tens of km farther down dip into sand‐starved bottomset/basin‐floor deposits. Only a few km along strike, the coeval foreset/slope deposits are bypass‐dominated with incisional features interpreted as minor slope conduits/gullies. The margin here is steeper, more channelized and records a stepped profile with evidence of sand‐filled intraslope topography, a preserved base‐of‐slope transition zone and sand‐rich bottomset/basin‐floor deposits. Unit G is interpreted as part of a composite depositional sequence that records a change in basin margin style from an underlying incised slope with large sand‐rich basin‐floor fans to an overlying accretion‐dominated shelf with limited sand supply to the slope and basin floor. The change in margin style is accompanied with decreased clinoform height/slope and increased shelf width. This is interpreted to reflect a transition in subsidence style from regional sag, driven by dynamic topography/inherited basement configuration, to early foreland basin flexural loading. Results of this study caution against reconstructing basin margin successions from partial datasets without accounting for temporal and spatial physiographic changes, with potential implications on predictive basin evolution models.

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Geodynamic interpretation of the Cape and Karoo basins, South Africa

Cited by 33 publications

References 125 publications

Development of a Dense Cratonic Keel Prior to the Destruction of the North China Craton: Constraints From Sedimentary Records and Numerical Simulation

Development of a Dense Cratonic Keel Prior to the Destruction of the North China Craton: Constraints From Sedimentary Records and Numerical Simulation

Vertebrate assemblages from the north-central Main Karoo Basin, South Africa, and their implications for mid-Permian biogeography

Clinoform architecture and along‐strike facies variability through an exhumed erosional to accretionary basin margin transition

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