The structural development of the early Proterozoic Birimian and tarkwaian rocks of southwest Ghana, West Africa

Eisenlohr, B.N.; Hirdes, W.

doi:10.1016/0899-5362(92)90035-b

Cited by 129 publications

(62 citation statements)

References 8 publications

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“…Our interpretation led us to define an early D1 tectonism, is in agreement with Milési et al [24]; Allibone et al [25], who also recognize the existence of an early event D1 in Eburnean orogeny. In this, we differ from the interpretation of some authors (Eisenlohr and Hirdes, [26]; Blenkinsop et al, [27]) who propose that all Eburnean structures are related to single event may correspond to our D2 and D3 phases.…”

Section: Makobasin-volcanism and Tectonics: Correlation Between Obliqcontrasting

confidence: 52%

Structural Evolution of a Precambrian Segment: Example of the Paleoproterozoic Formations of the Mako Belt (Eastern Senegal, West Africa)

Diène¹,

Gueye²,

Diallo³

et al. 2012

IJG

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The western part of the Kedougou Kenieba Inlier is located in the West African Craton. It consists of paleoproterozoic NE-trending elongate belts (subprovinces) of metavolcanic and granitic rocks that alternate with metasedimentary belts. Major linear fault such as the MTZ which also approximate a north-easterly trend form the eastern boundaries. The field observations and geophysics analyses were completed by a microscopic study. Based on these data we define across this region four lithostructural domains from east to west. The western domain is structurally complex. The rocks of this domain have been subjected to a complex history of polyphase deformation and metamorphism. The structural analyse allow us to distinguished three deformation events. The deformation results in the formation of D1 thrust tectonic and D2 and D3 transcurrent tectonic. The structural evolution of the Mako Belt is characterized by deformation dominated by the intrusion of large TTG batholiths (D1) followed by basins formation and transpression accommodating oblique convergence and collision (D2 and D3). The change from thrusting (D1 deformation to transcurrent motion (D2 and D3) is recorded in the marginal basin of the central domain and in Tinkoto pull apart basin. The timing of these basins indicates a diachronous evolution. Deformation styles within the basin are compatible with a dextral transpression which terminated at ca 2090 Ma. Small extensional basins formed over the rocks of the Mako Belt are filled with continental detrital sedimentary rocks that show weak foliation and active felsic volcanism. We suggest that the sinistral transpressive tectonic associated with oblique subduction may have generated the pull-apart basin and subaqueous volcanism. In part these features are now related to terrain accretion, thrusting and strike slip movement during oblique convergence. The inversion of the large scale structural evolution from thrusting to strike slip is common to modern orogenies.

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Section: Makobasin-volcanism and Tectonics: Correlation Between Obliqcontrasting

confidence: 52%

Structural Evolution of a Precambrian Segment: Example of the Paleoproterozoic Formations of the Mako Belt (Eastern Senegal, West Africa)

Diène¹,

Gueye²,

Diallo³

et al. 2012

IJG

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“…The red areas coincided with borehole points with hydraulic conductivity greater the 0.9 m/day whilst the white areas coincided with those with hydraulic conductivity less than 0.01 m/day. These trend suggest that the hydraulic conductivity is structurally controlled which confirm earlier work carried out in the region by Eisenlohr and Hirdes (Eisenlohr, 1989;Eisenlohr and Hirdes, 1992). Fig.…”

Section: Fig 5 Comparison Of Aquifer Thickness With (A) Yield and (Bsupporting

confidence: 80%

Hydrogeological Properties of the Rocks in Adansi Mining Area, Ghana

Asante-Annor

Ewusi

2016

Ghana Mining Journal

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Groundwater is an important resource in the Adansi mining area as some communities in the area are not connected to the Ghana national water network. These communities therefore utilise groundwater for potable water supply. The hydrogeological properties of an aquifer coupled with climatic conditions and geomorphology determines how much groundwater exists in that location. A hydrogeological study of the rocks in the Adansi area was carried out to obtain the aquifer hydraulic properties. Drilling and pumping test analysis information were used to assess these properties. The average borehole depth in the area was 44.3 m whilst the average static water level is 10.75 m. There is a general decrease in yield with an increase in borehole total depth. There is also no strong correlation between aquifer saturated thickness, yield and drawdown. Transmissivity of the aquifer decreases from the phyllite, argillitc sediments, granites to sandstone. Three hydrogeological regimes (> 0.9 m/day, 0.9 -0.09 m/day and < 0.09 m/day) were also realised based on the hydraulic conductivity. The spatial distribution of the hydraulic properties suggests the influence of geological structures on the occurrence of groundwater in the area.

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“…Milesi et al, (1989) and referred to the two deformations as compressive Dl and D2 deformations and associated them with Eburnean I and Eburnean II Orogenic Events. The orebodies at Prestea are hosted by complex shear zones located on the inverted limb of overturned folds (Cooper, 1934;Eisenlohr, 1989). In mine environs, thick sequences of northwesterly dipping phyllites, carbonaceous phyllites, metatuffs, metagreywackes and schists which have been isoclinally folded form overthrust faults and shear planes that trend northeast in many places.…”

Section: Structure and Metamorphismmentioning

confidence: 99%

“…1 ± 0.l Ga (Cohen et al, 1984) caused deformation and metamorphism to between pumpellyite-prehnite facies and almandine-amphibolite facies with most of the rocks being in the chlorite subfacies of the greenschist facies (Hirdes et al, 1993). Regional metamorphism does not exceed the greenschist/amphibolite transition (Eisenlohr, 1989;Eisenlohr and Hirdes, 1992), with quartz + muscovite as the typical metamorphic assemblages in the pelitic rocks. The absence of biotite is cited to indicate that the metamorphism did not exceed 420 °C.…”

Section: Structure and Metamorphismmentioning

confidence: 99%

“…Regionally, two deformation types, low strain and high strain, are recognised in Birimian rocks (Ledru et al, 1988;Eisenlohr 1989;Eisenlohr and Hirdes, 1992). The low strain deformation resulted in development of NE trending sub-vertical (S 1 ) foliation whilst rocks of the high strain deformation occur mostly along the northwestern margins of the volcanic belts near the contact with the Tarkwaian rocks and is characterised by a more intense penetrative NE trending (S 2 ) foliation that is represented by development of elongate recrystallised quartz grains and well aligned phyllosilicates.…”

Section: Structure and Metamorphismmentioning

confidence: 99%

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