China
Africa
Explore chapters and articles related to this topic
Performance of hard rock double shield TBM in tailrace tunnel of Uma Oya project, Sri Lanka
Published in Daniele Peila, Giulia Viggiani, Tarcisio Celestino, Tunnels and Underground Cities: Engineering and Innovation meet Archaeology, Architecture and Art, 2020
H. Darabi Kelareh, A. Rahbar Farshbar, A.H. Hosseini, F. Foroutan, D. Dodangeh
The Highland Complex is composed of supracrustal and metaigneous rocks in Sri Lanka. Most of the rocks in the complex have ancient ages of 2.0–3.4 billion years. The supracrustal rocks of the Highland Complex comprise of shallow-water metasediments consisting of meta-quartzites derived from sandstones; quartzo-feldspathic gneisses derived from Arkose (type of sandstone); pelitic gneisses derived from greywacky and shale; marbles derived from limestone and dolomitic limestone; as well as a subordinate bimodal volcanic suite. The metaigneous rocks of the Highland Complex are now charnockites and Charnochitic rocks (granular rocks consisting mainly of quartz, feldspar, and orthopyroxene, plus other minerals). Figure 1 shows the geological profile of tailrace tunnel (JV, 2011a).
Performance of hard rock double shield TBM in tailrace tunnel of Uma Oya project, Sri Lanka
Published in Daniele Peila, Giulia Viggiani, Tarcisio Celestino, Tunnels and Underground Cities: Engineering and Innovation meet Archaeology, Architecture and Art, 2019
H. Darabi Kelareh, A. Rahbar Farshbar, A.H. Hosseini, F. Foroutan, D. Dodangeh
The Highland Complex is composed of supracrustal and metaigneous rocks in Sri Lanka. Most of the rocks in the complex have ancient ages of 2.0–3.4 billion years. The supracrustal rocks of the Highland Complex comprise of shallow-water metasediments consisting of meta-quartzites derived from sandstones; quartzo-feldspathic gneisses derived from Arkose (type of sandstone); pelitic gneisses derived from greywacky and shale; marbles derived from limestone and dolomitic limestone; as well as a subordinate bimodal volcanic suite. The metaigneous rocks of the Highland Complex are now charnockites and Charnochitic rocks (granular rocks consisting mainly of quartz, feldspar, and orthopyroxene, plus other minerals). Figure 1 shows the geological profile of tailrace tunnel (JV, 2011a).
Tourmaline rocks associated with stratabound tungsten mineralisation in the Bonya Block, eastern Arunta Inlier, central Australia - Products of early or late boron metasomatism?
Published in Adam Piestrzyński, Mineral Deposits at the Beginning of the 21st Century, 2001
N. Schöner, J.G. Raith, T. Meisel
The supracrustal rocks (“Bonya Schist”) in the Bonya area, interpreted as a distal continental rift sequence (Schöner, 2000), are composed of various types of metapelites (e.g., andalusite or cordierite-bearing muscovite-biotite schist), fine- and coarsegrained calc-silicate rocks, and mafic to felsic metavolcanic rocks. They have been subdivided into several units (Units 1-6, Freeman, 1986), which are stratigraphically separated by a major metabasite horizon (Kings Legend Amphibolite Member, Fig. 1). Cu-bearing quartz-garnet veins and tourmaline rocks are minor rock types, the latter mainly occurring in the upper stratigraphic units. Early to Late Strangways granite and pegmatite (1.77 Ga and 1.71 Ga, respectively, Zhao & Bennett, 1995), intruded the Palaeoproterozoic supracrustal sequence.
The isotope geochemistry of host rocks of the late Archean Guandi and Banshigou banded iron formations, southern Jilin Province: temporal and tectonic significance
Published in Australian Journal of Earth Sciences, 2023
Southern Jilin Province is situated in the northern part of the EB and contains ∼7000 km2 of Archean crystalline basement (Figure 1b) (Lu et al., 2006) that consists of intensely foliated Tonalitic–Trondhjemitic–Granodioritic (TTG) gneisses, weakly foliated potassic granites, clinopyroxene granodiorites and minor amounts of supracrustal rocks (Sun et al., 1995). The TTG gneisses dominate the exposed Archean crystalline basement in this area and have undergone greenschist to lower amphibolite facies metamorphism (Guo et al., 2015). Available geochronological data indicate that the TTG gneisses were emplaced at 2.55–2.50 Ga (Liu & Xing, 2001) and yield Nd model ages of 2.8–2.7 Ga (Wu et al., 2005). The supracrustal rocks consist of ultramafic to felsic volcanic rocks, BIF, pelitic gneiss, felsic paragneiss, calc-silicate rocks and marble, all of which have undergone amphibolite facies metamorphism. These rocks yield U–Pb zircon ages of 2.55–2.50 Ga, which are considered to represent the time at which the supracrustal rock assemblage was deposited (Dai et al., 1990). The Paleoproterozoic supracrustal rocks (e.g. the Laoling and Ji’an groups) are exposed in the JLJB and consist of metamorphosed volcanic and sedimentary sequences, both of which were intruded by granitoid intrusions (Lu et al., 2006). Of these granitoids, the monzogranitic gneisses were emplaced at 2.19–2.14 Ga and metamorphosed at ca 1.91 Ga, and the porphyritic monzogranites and alkaline syenites were emplaced at 1.88–1.84 Ga (Tam et al., 2011; Zhou et al., 2008).