Clark R.L. Friend

Clark R.L. Friend
Chinese Academy of Geological Sciences | CAGS

BSC, PhD

About

214
Publications
49,597
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
10,959
Citations

Publications

Publications (214)
Article
In the early 1970s, Vic McGregor and Stephen Moorbath demonstrated that the Isua supracrustal belt (Greenland) and its surrounding orthogneisses formed in the Eoarchean (Moorbath et al., 1972, 1973). Fifty years later, these rocks are a key resource globally for understanding the Eoarchean Earth. This is because there is an extensive area (∼200 km²...
Article
Full-text available
The two Isua supracrustal belt area (Greenland) papers by Zuo et al. (2021, https://doi.org/10.1029/2020tc006514) and Ramírez‐Salazar et al. (2021, https://doi.org/10.1029/2020TC006516) contain no evidence supporting an Eoarchean “heat‐pipe” geodynamic regime and yet no evidence negating a mobile lid one. From quartz micro‐fabric studies, Zuo et al...
Article
It is 50 years since the landmark paper where Black et al. (1971) presented whole-rock Pb-Pb and Rb-Sr isotopic evidence for some rocks in Greenland surviving from Earth’s first billion years; the ≥ 3700 Ma Amîtsoq gneisses. This overturned ideas prevalent at that time that the young Earth was far too violent for such ancient rocks to survive. In t...
Article
The ~ 3700 Ma Inner Arc Group of the Isua supracrustal belt (Greenland) contains a 10 km long strip of ultramafic schists with two ≤ 1 km long meta-dunite lenses, preserving relict olivine + antigorite + titano-clinohumite and titano-chondrodite ~ 2.6 GPa ultra-high-pressure (UHP) assemblages. There are two distinct relict meta-peridotite variants:...
Article
Greenland’s Itsaq Gneiss Complex (IGC) shows Eoarchean (>3600 Ma) 250-400°C/GPa (low T/P – high pressure) and ≥1000°C/GPa (high T/P) metamorphic regimes, demonstrating a similarity of contrasting metamorphic T/P regimes from the Phanerozoic back to the start of Earth’s rock record. Low T/P metamorphism produced: (i) Deep crustal eclogitised mafic r...
Article
The Eoarchean (>3600 Ma, or millions of years ago) folded and metamorphosed Isua supracrustal belt and the adjacent orthogneiss exposures of Greenland contain rare low deformation lenses that display some uniquely-preserved components of Earth's oldest rock record. These include world's oldest (but contested) stromatolites in dolomitic carbonates,...
Article
The rare preservation of a stratigraphy in the northwest of the Eoarchean Isua supracrustal belt (Greenland) demonstrates the world's earliest-recognised marine transgression. Stratigraphically lowest is the ~3710 Ma Solvang Volcanic Formation of picrites, basalts and basaltic-andesites with arc-like geochemical signatures. Close to its erosional t...
Technical Report
This report concerns the controversy about structures that some researchers (Nutman et al.) interpret as relic 3,700 million year old stromatolites in the Isua supracrustal belt (Greenland), whereas others interpret them to be abiogenic features produced solely by deformation and metamorphism.
Article
The ∼3700 Ma and 3800 Ma meta-volcanic and -sedimentary rocks in the Isua supracrustal belt (Greenland) were affected by heterogeneous ductile deformation under amphibolite facies conditions (∼500–650 °C), and variably modified by secondary silica and carbonate mineralisation deposited from diagenetic and metasomatic fluids. Rare low-deformation ar...
Article
Prior to 1970 grey gneiss complexes were interpreted as partially-melted sedimentary sequences. Once it was recognised from the Nuuk region that they comprised calc-alkaline igneous complexes, it was understood that such complexes world-wide were dominated by TTG (trondhjemite-tonalite-granodiorite) initially found to have juvenile Sr, Nd and, subs...
Article
Full-text available
Estimates of early atmosphere compositions from metamorphosed banded iron formations (BIFs) including the well-studied ≥3.7 BIFs of the Isua supracrustal belt (Greenland) are dependent on knowledge of primary versus secondary Fe-mineralogical assemblages. Using new observations from locally well preserved domains we interpret that a previously assu...
Chapter
The folded, amphibolite facies Isua supracrustal belt of the North Atlantic Craton (Greenland) contains rare low-strain lacunae that display the world's oldest sedimentary structures in dolomitic carbonates, banded iron formations, volcaniclastic sedimentary rocks, and very rare sandstones and conglomerates. U-Pb zircon geochronology shows that Isu...
Article
Full-text available
Biological activity is a major factor in Earth's chemical cycles, including facilitating CO2 sequestration and providing climate feedbacks. Thus a key question in Earth's evolution is when did life arise and impact hydrosphere-atmosphere-lithosphere chemical cycles? Until now, evidence for the oldest life on Earth focused on debated stable isotopic...
Article
Full-text available
The extension of subduction processes into the Eoarchaean era (4.0-3.6 Ga) is controversial. The oldest reported terrestrial olivine, from two dunite lenses within the ∼ 3,720 Ma Isua supracrustal belt in Greenland, record a shape-preferred orientation of olivine crystals defining a weak foliation and a well-defined lattice-preferred orientation (L...
Article
This paper reports evidence for Earth's oldest-recognised low temperature alteration, at ~3800. Ma. Potassic felsic schists with a protolith age of 3806 ± 2. Ma form a ~30. km long unit in the amphibolite facies, deformed, Isua supracrustal belt (West Greenland). At a single locality, boudinaged layers (nodules) within the schists are low strain zo...
Article
A synthesis of the geological record of Earth's ten remaining oldest surviving gneiss complexes, each containing >3.6 Ga rocks, reveals a common history. We propose that the simplest scenario compatible with all observations is that of formation of an ancient continental mass, here named Itsaqia, by 3.66 Ga from amalgamation of earlier quartzofelds...
Article
The Mesoarchaean Kapisilik and Eoarchaean Isukasia terranes in the Nuuk region of southern West Greenland were tectonically juxtaposed in the Archaean. The north of the Isukasia terrane is distal from the Kapisilik terrane and has only rare growth of ∼2690 Ma metamorphic zircon and no 2980–2950 Ma metamorphic zircon. The southern part of the Isukas...
Article
Full-text available
From the 3000 km2 Eoarchean Itsaq Gneiss Complex (IGC) of Greenland, zircon U-Pb dating of numerous meta-granitoid and orthogneiss samples is integrated with geologic observations, whole rock geochemistry and a strategic subset of zircon Hf and whole rock Nd isotopic measurements. This shows that there are multiple episodes of TTG suite formation f...
Article
Wood Farm Pit, Bubbenhall, Warwickshire, central England, was one of a complex of sand and gravel quarries within unconsolidated Middle Pleistocene fluvial and glaciogenic sediments of the Baginton and Wolston formations. These strata document the development of the pre-Anglian Bytham River and its eventual destruction during the Anglian glaciation...
Article
Full-text available
Eoarchaean juvenile crust formed as 'proto-arcs'. The northern side of the Isua supracrustal belt is an archetypal proto-arc, with ≥3720 Ma boninites, c. 3720 Ma basalts and gabbros, 3720-3710 Ma andesites, diorites and mafic tonalites, 3710-3700 Ma intermediate-felsic volcanic and sedimentary rocks and 3700-3690 Ma chemical sedimentary rocks. On i...
Article
Full-text available
The majority of >3 Ga metabasalts have chemical features, such as high field strength element (HFSE) depletions, that are characteristic of modern island-arc basalts. These compositions have been interpreted as evidence for subduction of oceanic crust early in Earth's history. Alternatively, the apparent absence of Archean mafic rocks with mid-ocea...
Article
Storm wave structures in Isua metasedimentary rocks and signatures of chemical weathering in Eoarchean igneous rocks support the idea that Earth's climate at 3.8-3.7 Ga was equable rather than entirely frigid.
Article
The eastern part of the North China Craton in eastern Hebei Province contains metamorphosed and deformed Neoarchaean to earliest Palaeoproterozoic rocks (∼2550–2490 Ma) with some older Archaean rocks. Numerous precise U–Pb zircon ages, structural observations, Nd and Hf isotopic data and whole rock geochemistry (our new data with reassessment and i...
Article
Full-text available
The chemistry of surviving pieces of Eoarchaean mantle together with related crust helps us determine early crust-forming mechanisms. Two lenses of high-Mg, low-Al dunite within a ca. 3720 Ma part of the Isua supracrustal belt in Greenland are interpreted as relicts of Eoarchaean mantle with minimal crustal disturbance. The lenses are within altere...
Article
Full-text available
The Archean gneiss complex of West Greenland contains packages of unrelated rocks created during relatively short periods of time in arc-like magmatic environments, and having similarities to rocks formed at Phanerozoic convergent plate boundaries. The terranes of new Archean crust were amalgamated by collisional orogeny and then partitioned by pos...
Article
Full-text available
The Eoarchean Isua supracrustal belt (Greenland) comprises two distinct packages that have been dated at ca. 3800 Ma and 3700 Ma. Both packages consist of strongly deformed, pillow lavas and lesser amounts of gabbro (island arc tholeiite, picrite and boninite protoliths), felsic schists (andesite-dacite protoliths), chemical sedimentary rocks and d...
Article
Full-text available
Chemical sedimentary rocks such as banded iron formation (BIF) and pillow basalts are persistent features of the oldest volcanic and sedimentary record by 3.8–3.7 Ga, and are direct evidence for oceans by the start of the Archean. However, their presence does not dictate an equitable 3.8–3.7 Ga terrestrial climate. This is because they could have f...
Article
Field studies integrated with cathodoluminescence petrography and SHRIMP U–Pb dating of zircons from >150 orthogneisses and metatonalites from the Eoarchaean Itsaq Gneiss Complex (southern West Greenland) shows that only a minority contain ≥3840 Ma zircons, whereas the majority carry only younger ones. Rocks containing ≥3840 Ma zircons vary from ve...
Article
Full-text available
New SHRIMP U–Pb zircon geochronology and fieldwork integrated with reappraisal of earlier mapping demonstrates that the so-called ‘southern region’ of the mainland Lewisian Gneiss Complex comprises a package of distinct tectono-stratigraphic units. From south to north these are the Rona (3135–2889Ma), Ialltaig (c. 2000Ma) and Gairloch (ca. 2200Ma)...
Article
Full-text available
The Lewisian Gneiss Complex of northwestern Scotland consists of Archaean gneisses, variably reworked during the Proterozoic. It can be divided into three districts - a central granulitefacies district between districts of amphibolite-facies gneiss to the north and south. Recent work has interpreted these districts in terms of separate terranes, in...
Article
In situ LA-ICP-MS monazite geochronology from a garnet-bearing diatexite within the Moine Supergroup (Glenfinnan Group) NW Scotland records three temporally distinct metamorphic events within a single garnet porphyroblast. The initial growth of garnet occurred in the interval c. 825–780 Ma, as recorded by monazite inclusions located in the garnet c...
Article
Full-text available
The amphibolite facies Eoarchaean Isua supracrustal belt (northern part of the Nuuk region, southern West Greenland) is dominated by strongly deformed metabasalts, with chert, banded iron formation, felsic volcanic and volcano-sedimentary rocks and minor gabbro and sedimentary carbonates. It comprises a suture zone between a northern terrane formed...
Article
Full-text available
Eoarchaean crust in West Greenland (the Itsaq Gneiss Complex, 3870-3600 Ma) is >80% by volume orthogneisses derived from plutonic tonalite-trondhjemite-granodiorite (TTG) suites, <10% amphibolites derived from basalts and gabbros, <10% crustally derived granite,<1% metasedimentary rocks and ≪1% tectonic slices of upper mantle peridotite. Amphibolit...
Article
We present new major and trace element data for rare examples of preserved pillow basalts from a locality of little studied > 3800 Ma rocks at the southwestern edge of the Isua Supracrustal Belt (ISB), West Greenland. The 20 samples have 47.3–59.0 wt.% SiO2, 4.9–12.2 wt.% MgO, 6.5–11.2 wt.% CaO, 60–340 ppm Ni and 63–1094 ppm Cr, consistent with pre...
Article
The Ikkattoq gneisses of the Archaean gneiss complex in the Nuuk region, southern West Greenland, are the orthogneiss component within the amphibolite facies Tre Brødre terrane. They have mostly granodioritic compositions, with a small amount of quartz diorite. Sm–Nd isotopic data for a quartz diorite and five granodiorite Ikkattoq gneiss samples f...
Article
It is proposed that the vitrification in some Iron Age forts in NW Scotland can be explained through decomposition of micas (largely biotite) giving melts that react with or dissolve quartz and crystallise orthopyroxene and feldspars, so equating with the reaction biotite + quartz = sanidine + orthopyroxene + liquid. A sample of Moine semi-pelite h...
Article
Full-text available
Basement gneiss inliers within the Scottish Caledonides have been conventionally correlated with the Archaean Lewisian Gneiss Complex of the Caledonian foreland. Alternatively, the inliers could represent allochthonous terranes accreted to Laurentia before or during the Caledonian orogeny. SIMS U-Pb zircon dating indicates that the Ribigill, Borgie...
Article
Full-text available
The 200 km wide, east-west trending Paleoproterozoic mobile belt of the Ammassalik region of South-East Greenland contains a diverse assemblage of Paleoproterozoic and Archean rocks, variably affected by Paleoproterozoic deformations and high-grade low or high pressure metamorphism. By using previous field and geochemical data combined with new zir...
Article
Full-text available
Duke, M. (2009). The whole rock Sm-Nd 'age' for the 2825 Ma Ikkattoq gneisses (Greenland) is 800 Ma too young: Insights into Archaean TTG petrogenesis. Chemical Geology, 261 (1-2), 62-76.
Article
The ca. 3000 km2 Itsaq Gneiss Complex of the Nuuk region, southern West Greenland was the first body of pre-3600 Ma crust discovered. Such ancient gneisses are now also known elsewhere, but in total form only about a millionth of the modern crust. The other 99.9999% of ancient crust was destroyed by melting and erosion over billions of years. Under...
Article
Full-text available
Furnes et al. (Reports, 23 March 2007, p. 1704) reported the identification of an ophiolite sequence within the approximately 3.8-billion-year-old Isua supracrustal belt. However, they did not acknowledge that the belt contains supracrustal rocks and mafic dikes of different ages, nor did they demonstrate that the proposed components of the ophioli...
Article
Full-text available
The Eoarchaean (>3,600Ma) Itsaq Gneiss Complex of southern West Greenland is dominated by polyphase orthogneisses with a complex Archaean tectonothermal history. Some of the orthogneisses have c. 3,850Ma zircons, and they vary from rare single phase metatonalites to more common complexly banded migmatites. This is due to heterogeneous strain, in si...
Article
Gold on Storø (in the Nuuk region of southern West Greenland) occurs in a slice of strongly deformed, amphibolite facies, Neoarchaean quartzo-feldspathic metasedimentary rocks and amphibolites in tectonic contact with the Eoarchaean Færingehavn terrane and the Meso- to Neoarchaean Akia terrane. The gold is associated with either löllingite (FeAs) +...
Article
New field and laboratory work has been carried out on two vitrified forts, Rhubh Aird Ghamhsgail near Arisaig and The Torr near Acharacle. Fieldwork confirms that both are constructed from rubble largely comprising local psammitic Moine Supergroup rocks and that their walls are relatively well preserved with large portions of vitrified material rem...
Article
Heat transfer in falling liquid film systems is enhanced by waviness. Comprehension of the underlying kinetic phenomena requires experimental data of the temperature field with high spatiotemporal resolution. Therefore a non-invasive measuring method based on luminescence indicators is developed. It is used to determine the temperature distribution...
Article
Full-text available
In the gneiss complex of the Nuuk region of the North Atlantic Craton in southern West Greenland, terrane juxtaposition was followed by Neoarchaean folding under amphibolite facies conditions, with widespread low-pressure recrystallisation (5 kbar and 550–700 °C). The complex metamorphic overprinting requires that the P–T history related to actual...
Article
Relict discordant relationships between the c.3000–2800 Ma old Nǔk granitic (s.l.) gneisses and the c.3700 Ma old Amǐtsoq gneisses of Ivisǎrtoq clearly indicate that the Nǔk gneisses originated as intrusive sheets and bosses. The older gneisses are preserved as continuous banded units which are injected by thin granitic dykes and sills and become p...
Article
Modern chemical sediments display a distinctive rare earth element+yttrium (REE+Y) pattern involving depleted LREE, positive La/La*SN, Eu/Eu*SN, and YSN anomalies (SN=shale normalised) that is related to precipitation from circumneutral to high pH waters with solution complexation of the REEs dominated by carbonate ions. This is often interpreted a...
Article
The world's oldest sediments occur in high-grade terrains that were recrystallised during polyphase amphibolite to granulite metamorphism (>500 °C) accompanied by intense ductile deformation, during which, open system behaviour can corrupt any biogenic carbon-isotopic signatures. A 13C-depleted signature from apatites in the Akilia BIF (quartz + ma...
Article
Full-text available
Graham Park writes: The terrane model of Kinny et al. (2005; see also Friend & Kinny 2001) presents a radically different picture of the Lewisian complex from the ‘traditional’ view of a single piece of Archaean crust that has been subsequently modified and augmented in various Proterozoic events. The authors are to be congratulated on their attemp...
Article
Full-text available
The Itsaq Gneiss Complex of the Nuuk region, southern West Greenland, is dominated by 3850-3690 Ma tonalites intruded into and intercalated with lesser amounts of different ≥3850-3700 Ma supracrustal units. Published wholerock Sr and Nd isotopic studies demonstrate that the tonalites are juvenile crustal additions from a depleted mantle source. Fro...
Article
Full-text available
On the Nuussuaq peninsula, Western Greenland sedimentary deposits of glass spherules also contain high Ir, Co, Ni, and Cu anomalies. The iron-rich silicate glass spherules (to ∼3 wt% NiO, ∼35 wt% FeO) are highly circular in cross section. They show surface dissolution, smectite replacement and calcite infilling of vesicles, though many glasses are...
Article
In the south of the Nuuk region of West Greenland our 1980s mapping recognized four Archaean gneiss terranes (Faeringehavn, Tre Brodre, Tasiusarsuaq and Akia terranes) with different protolith ages and separate early tectonothermal histories. Later in the Archaean these were juxtaposed and then experienced the same 2700-2500 Ma tectonothermal event...
Article
Full-text available
The current nomenclature for the Lewisian Gneiss Complex has evolved from lithological and structural correlations made prior to any dating. Initial (flawed) geochronological studies gave some names an apparent chronological standing but, as work advanced, fitting events into a coherent regional framework became increasingly difficult. Modern datin...
Chapter
Book synopsis: On the Nuussuaq peninsula, Western Greenland sedimentary deposits of glass spherules also contain high Ir, Co, Ni, and Cu anomalies. The iron-rich silicate glass spherules (to ∼3 wt% NiO, ∼35 wt% FeO) are highly circular in cross section. They show surface dissolution, smectite replacement and calcite infilling of vesicles, though ma...
Article
Geochemical methods to advance knowledge on the early Earth require supplies of well-preserved >3600 Ma rocks and minerals (e.g. zircon). One of the most important resources for these are small domains within high metamorphic grade Palaeoarchaean gneisses in the Archaean Craton, southern West Greenland. In the Nuuk region these gneisses occur as tw...
Article
The ground truth of mantle models, particularly for the early Earth, relies on accurate determinations of original isotopic compositions. The 147Sm-143Nd isotopic system can provide the most complete record of mantle differentiation processes, when combined with intensive field and geochronologic studies leading to judicious sample selection. Our o...
Article
U-Pb zircon data from selected gneiss samples provide estimates of the timing of igneous protolith emplacement and granulite facies metamorphism in the Gruinard Bay, Badcall Bay and Lochinver areas of the mainland Lewisian Gneiss Complex of north-west Scotland. Zircons from the gneisses contain complex zoning patterns making them amenable to SHRIMP...
Article
This paper presents SHRIMP U-Pb zircon dating on four Meso- to Palaeoarchaean amphibolite-facies Ameralik dykes of differing compositions scattered throughout the Palaeoarchaean (3850-3600 Ma) amphibolite-granulite-facies Itsaq Gneiss Complex in the Nuuk district, southern West Greenland. In the north of the complex near the Isua supracrustal belt,...
Article
Full-text available
Within the Caledonides of Caithness, Scotland, the Neoproterozoic metasedimentary rocks of the Moine Supergroup are intruded by minor sheets of strongly deformed granite. U-Pb sensitive high-resolution ion microprobe zircon ages of 599 +/- 9 Ma (Berriedale augen granite) and 588 +/- 8 Ma (Braeval augen granite) are interpreted to date emplacement d...
Article
Since the pioneering days of Peach, Horne and Clough the Lewisian Gneiss Complex has become a classic geological area, representing the first piece of gneissic crust recognized as preserving a section through lower crust. Because of its accessibility it has become a place where new hypotheses have been tried and tested with varying degrees of succe...
Article
Peridotites from southern West Greenland are currently the best characterised "sample" of the early Archean upper mantle. As such they are the focus of integrated geochemical, geochronological, field investigations and are providing unique insights into early earth processes including the role of impacts, early Earth environments, mantle evolution...
Article
Full-text available
Detrital and inherited zircons from rocks of the Moine Supergroup from structural and stratigraphic positions above and below the Sgurr Beag and Naver thrusts have been dated by ion microprobe. Pb-207/Pb-206 ages for 65 detrital zircons from the Moine Nappe (Moray Group) range between 2707 and 947 Ma, with a bimodal distribution with clusters at c....
Article
Full-text available
Within the Caledonides of central Sutherland, Scotland, the Neoproterozoic metasedimentary rocks of the Moine Supergroup record NW-directed D2 ductile thrusting and nappe assembly, accompanied by widespread tight-to-isoclinal folding and amphibolite-facies metamorphism. A series of metagranite sheets which were emplaced and penetratively deformed d...