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Journal articles on the topic 'Geology, Stratigraphic – Archaean'

Author: Grafiati

Published: 4 June 2021

Last updated: 20 February 2023

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1

van Loon, A. J., R. Mazumder, and S. De. "Unravelling the depositional environment of the Archaean Rajkharsawan conglomerate (Jharkhand, eastern India)." Netherlands Journal of Geosciences - Geologie en Mijnbouw 91, no. 1-2 (September 2012): 129–35. http://dx.doi.org/10.1017/s0016774600001542.

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AbstractLarge conglomerate lenses occur in a fine-grained siliciclastic succession of the Singhbhum craton, eastern India. They overlie an Archaean orthogneiss, from which they are separated by a palaeosol. Neither the conglomerates nor the directly overlying rocks have been dated, but the conglomerate unit is assumed to have also an Archaean age. The conglomerate lenses occur within a succession of pelitic and mafic schists, and the depositional environment of this conglomerate/schist unit had not been clarified thus far. On the basis of a combination of the vertical and horizontal distribution of the conglomerates, their stratigraphic position and analysis of their sedimentological characteristics and the sedimentological context, it is concluded that the succession must have developed in a fluvial lowland environment where volcanic input contributed significantly to the sediment accumulation.

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2

Hicks, N., and D. J. C. Gold. "A reinterpretation of the Archaean stratigraphy south of Nkandla, southern Kaapvaal Craton, South Africa: Geophysical and stratigraphic constraints on a sheared granitoid-greenstone remnant." South African Journal of Geology 124, no. 3 (September 1, 2021): 685–98. http://dx.doi.org/10.25131/sajg.124.0025.

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Abstract A new lithostratigraphic framework based upon a review of historic data, field mapping and remote sensing, including aerial photography, high-resolution airborne aeromagnetic and radiometric data, is proposed for the Archaean geology along the southeastern margin of the Kaapvaal Craton, South Africa. A synthesis of new and existing data reveals that previously accepted lithostratigraphic schemes require complete revision, with reinterpretations identifying multiple major shear zones and previously unidentified granitoid successions along the margin of the craton. In this new lithostratigraphic framework, lithologies of the Southern Syncline previously correlated with the Nsuze Group of the Pongola Supergroup, are redefined as greenstone lithologies associated with the Ilangwe Greenstone Belt. The geology of the Nkandla region can be subdivided into five distinct geophysical domains including: (i) an extension of the Ilangwe Greenstone Belt, (Domain 1) which is subdivided into; a lower volcanic succession, the Thathe Formation, comprising pillow and amygdaloidal volcanics; the adjoining Sabiza Formation, comprising pillow volcanics exposed in the southeast of the study area; the volcano-sedimentary Mtshwili Formation, which overlies the Thathe and Sabiza formations, consisting of quartz (sericite) schist, phyllite, metavolcanics and iron formation; the Nomangci Formation, which occurs as a region of highly deformed quartz-kyanite-sericite schists, and the Simbagwezi Formation, which comprises maroon to green phyllites and schists in the north of the study area. (ii) granitoids of the Impisi Granitoid Suite (Domain 2) which border the greenstone succession to the north, intruding the Nomangci and Simbagwezi formations. (iii) a southern complex of sheared granitoids termed the Umgabhi Granitoid Suite (Domain 3), which intrudes the Thathe, Sabiza and Mtshwili formations. (iv) The two remaining domains, comprise the Mesoproterozoic Mfongosi and Ntingwe Groups (Domain 4) and Mesoarchaean volcano-sedimentary sequences of the Pongola Supergroup (Domain 5).

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3

Hickman-Lewis, K., and F. Westall. "A southern African perspective on the co-evolution of early life and environments." South African Journal of Geology 124, no. 1 (March 1, 2021): 225–52. http://dx.doi.org/10.25131/sajg.124.0016.

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Abstract The Kaapvaal and Zimbabwe cratons host some of the earliest evidence for life. When compared to the contemporaneous East Pilbara craton, cherts and other metasedimentary horizons in southern Africa preserve traces of life with far greater morphological and geochemical fidelity. In spite of this, most fossiliferous horizons of southern Africa have received relatively limited attention. This review summarises current knowledge regarding the nature of early life and its distribution with respect to environments and ecosystems in the Archaean (>2.5 Ga) of the region, correlating stratigraphic, sedimentological, geochemical and palaeontological understanding. There is abundant and compelling evidence for both anoxygenic photosynthetic and chemosynthetic biomes dominating Palaeoarchaean-Mesoarchaean strata dating back to around 3.5 Ga, and the prevalence of each is tied to palaeoenvironmental parameters deducible from the rock record. Well-developed, large stromatolites characteristic of younger Mesoarchaean-Neoarchaean sequences were probably constructed by oxygenic photosynthesisers. Isotopic evidence from the Belingwe greenstone belt and the Transvaal Supergroup indicates that both a full sulphur cycle and complex nitrogen cycling were in operation by the Mesoarchaean-Neoarchaean. The Archaean geological record of southern Africa is thus a rich repository of information regarding the co-evolving geosphere and biosphere in deep time.

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4

Friend, C. R. L., and A. P. Nutman. "Tectono-stratigraphic terranes in Archaean gneiss complexes as evidence for plate tectonics: The Nuuk region, southern West Greenland." Gondwana Research 72 (August 2019): 213–37. http://dx.doi.org/10.1016/j.gr.2019.03.004.

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5

MARTIN, D. McB, C. W. CLENDENIN, B. KRAPEZ, and N. J. McNAUGHTON. "Tectonic and geochronological constraints on late Archaean and Palaeoproterozoic stratigraphic correlation within and between the Kaapvaal and Pilbara Cratons." Journal of the Geological Society 155, no. 2 (March 1998): 311–22. http://dx.doi.org/10.1144/gsjgs.155.2.0311.

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6

Kenny, Gavin G., Gary J. O’Sullivan, Stephen Alexander, Michael J. Simms, David M. Chew, and Balz S. Kamber. "On the track of a Scottish impact structure: a detrital zircon and apatite provenance study of the Stac Fada Member and wider Stoer Group, NW Scotland." Geological Magazine 156, no. 11 (April 24, 2019): 1863–76. http://dx.doi.org/10.1017/s0016756819000220.

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AbstractThe Stac Fada Member of the Stoer Group, within the Torridonian succession of NW Scotland, is a melt-rich, impact-related deposit that has not been conclusively correlated with any known impact structure. However, a gravity low approximately 50 km east of the preserved Stac Fada Member outcrops has recently been proposed as the associated impact site. We investigate the location of the impact structure through a provenance study of detrital zircon and apatite in five samples from the Stoer Group. Our zircon U–Pb data are dominated by Archaean grains (> 2.5 Ga), consistent with earlier interpretations that the detritus was largely derived from local Lewisian Gneiss Complex, whereas the apatite data (the first for the Stoer Group) display a single major peak at c. 1.7 Ga, consistent with regional Laxfordian metamorphism. The almost complete absence of Archaean-aged apatite is best explained by later heating of the > 2.5 Ga Lewisian basement (the likely source region) above the closure temperature of the apatite U–Pb system (c. 375–450°C). The U–Pb age distributions for zircon and apatite show no significant variation with stratigraphic height. This may be interpreted as evidence that there was no major change in provenance during the course of deposition of the Stoer Group or, if there was any significant change, the different source regions were characterized by similar apatite and zircon U–Pb age populations. Consequently, the new data do not provide independent constraints on the location of the structure associated with the Stac Fada Member impact event.

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7

Yu, Hongchao, Jin Liu, Zhonghua He, Zhenghong Liu, Changquan Cheng, Yujie Hao, Chen Zhao, Hongxiang Zhang, and Yachao Dong. "Geochronology and Zircon Hf Isotope of the Paleoproterozoic Gaixian Formation in the Southeastern Liaodong Peninsula: Implication for the Tectonic Evolution of the Jiao-Liao-Ji Belt." Minerals 12, no. 7 (June 22, 2022): 792. http://dx.doi.org/10.3390/min12070792.

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The Jiao-Liao-Ji belt (JLJB), in the Eastern Block of the North China Craton, is a major Paleoproterozoic orogen and underwent a complicated tectonic evolution during 2.2–1.8 Ga. The Liaohe Group, an important stratigraphic unit in the JLJB, is key to understanding the complex evolution of this belt. In this paper, we present new detrital zircon U–Pb ages and Hf isotope data for meta-sedimentary rocks from the Gaixian Formation in different areas of the JLJB, in addition to compiled data for other formations of the Liaohe Group, to establish the depositional age and source of detrital materials of the group. U–Pb age results show that the age ranges of zircons from the different samples are broadly similar. The youngest zircon group is ca. 2.06 Ga, and the youngest single-grain age is ca. 2.0 Ga, constraining the depositional age of the Gaixian Formation to between 2.0 Ga and the metamorphic age of ca. 1.9 Ga. The zircon age data indicate that the provenance was primarily Archaean basement of the Nangrim Block and Paleoproterozoic volcanic rocks of the Li’eryu Formation. On the basis of the new geochronological data and results from previous studies, it is inferred that the JLJB underwent a successive process of rifting–subduction–collision, with the different formations of the Liaohe Group being deposited in different stages from rift to passive continental margin and then to active continental margin. Zircon Hf isotope data from the JLJB and adjoining Longgang and Nangrim blocks indicate that a major crustal growth event occurred at 2.9–2.5 Ga, followed by crustal growth and intense recycling of ancient crust at ca. 2.2 Ga.

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8

JASTRZĘBSKI, MIROSŁAW, ANDRZEJ ŻELAŹNIEWICZ, IZABELLA NOWAK, MENTOR MURTEZI, and ALEXANDER N. LARIONOV. "Protolith age and provenance of metasedimentary rocks in Variscan allochthon units: U–Pb SHRIMP zircon data from the Orlica–Śnieżnik Dome, West Sudetes." Geological Magazine 147, no. 3 (November 2, 2009): 416–33. http://dx.doi.org/10.1017/s0016756809990501.

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AbstractNew U–Pb sensitive high-mass resolution ion microprobe (SHRIMP) data from detrital zircons within the Orlica–Śnieżnik Dome provide new insights into the stratigraphic and palaeogeographic position of assumed relict Precambrian basement preserved in the Variscan collisional orogen of the West Sudetes, SW Poland. Hitherto, the Młynowiec Formation and the Stronie Formation within the Orlica–Śnieżnik Dome were assumed to represent two metavolcano-sedimentary successions of Proterozoic and early Palaeozoic age, respectively. However, when previous U–Pb data and mapping data from the Orlica–Śnieżnik Dome are combined with the new detrital zircon isotopic ages both from paragneisses within the Młynowiec Formation and from light-coloured quartzites and mica schists within the Stronie Formation, the result strongly suggests that the protoliths of these two formations actually form a continuous succession. This continuous succession is herein designated the Młynowiec–Stronie Group. The rocks of this group were deposited during middle Cambrian–early Ordovician times (c.520–470 Ma), presumably at the northern edge of West Gondwana after the 10–20 Ma period of tectonic quiescence that followed the terminal stage of the Cadomian collisions. Monotonous Młynowiec metagreywackes form the lower part of the succession, and the lithologically diverse schistose Stronie Formation forms its upper part. The change from greywacke (Młynowiec) to volcano-sedimentary (Stronie) facies coincided with the onset of rather short-lived volcanic activity which climaxed around 505–495 Ma and which supplied the volcanogenic components to the Stronie Formation. No ‘Cadomian unconformity’ has been observed in the region. Xenocrystic zircons from the Młynowiec–Stronie Group retain records of Archaean (3.0–2.3 Ga), Palaeoproterozoic (2.1–1.8 Ga) and Neoproterozoic to early Cambrian (660–530 Ma) zircon-forming events. These zircon ages, together with the lack of 1.7–1.2 Ga zircon ages, suggest that the source areas for the metasedimentary rocks may have been the West Africa craton, which therefore differs from the Amazonian affinity of the adjacent Brunovistulia Terrane. Nevertheless, two zircons,c.1.0 and 1.1 Ga old, respectively, indicate that the Młynowiec–Stronie Group sedimentary basin must have still been within the delivery reach of detritus ultimately derived from the Grenvillian-age belt(s). The detrital components of the supracrustal formations of the Orlica–Śnieżnik Dome were mainly derived from Neoproterozoic zircon-bearing crystalline rocks that were accreted to, and included in, the Cadomian basement in several intrusive pulses that culminated at 660–640 Ma, 620 Ma and 570–530 Ma.

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9

Higgins, A. K. "Geology of central and eastern North Greenland." Rapport Grønlands Geologiske Undersøgelse 128 (December 31, 1986): 37–54. http://dx.doi.org/10.34194/rapggu.v128.7923.

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A historical review of geological research in North Greenland is followed by a summary of the main results of the 1978-80 GGU expeditions to the region. New outcrops of Archaean and early Proterozoic crystalline rocks are recorded only as xenoliths in dykes and volcanic centres. A revised stratigraphy is applied to the middle Proterozoic Independence Fjord Group sandstones, while petrographic and isotopic studies have been made of the cross-cutting Midsommersø dolerites and the overlying Zig-Zag Dal Basalt Formation. No convincing evidence has been found of a Carolinidian orogenic episode separating these units from succeeding late Proterozoic sedimentary sequences. Lower Palaeozoic sediments dominate North Greenland and are divided into southern shelf and northern trough successions; new or revised stratigraphies are now applied in both settings. The shelf-trough boundary can be shown to have moved south with time, and a major early Silurian expansion of the trough is related to shelf subsidence and a new phase of turbidite deposition derived from the rising East Greenland Caledonian mountains. Devonian - Middle Carboniferous (Ellesmerian) deformation brought deposition to a close and created the North Greenland fold belt, in which deformation intensity and metamorphic grade increase northwards. Thin-skinned thrusting in association with west or south-facing folds is important in southern areas; this is one of the main differences in interpretation compared to earlier work in the fold belt. New outcrops of post-ElIesmerian sediments (Wandel Sea Basin) have mainly been recorded as fault or thrust bounded sequences; a new stratigraphy is applied to the Wandel Sea Basin succession. Cretaceous - Tertiary events include a suite of volcanic centres, dyke swarms, the Kap Washington Group volcanics, and faults and thrusts of Tertiary (Eurekan) age; all have been studied anew, as have the Quaternary deposits.

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10

Wilks, M. E., and E. G. Nisbet. "Stratigraphy of the Steep Rock Group, northwest Ontario: a major Archaean unconformity and Archaean stromatolites." Canadian Journal of Earth Sciences 25, no. 3 (March 1, 1988): 370–91. http://dx.doi.org/10.1139/e88-040.

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The Archaean Steep Rock Group of northwest Ontario, situated in the Wabigoon Subprovince of the Superior Province, Canada, comprises five formations: Wagita Formation (clastics), Mosher Carbonate, Jolliffe Ore Zone, Dismal Ashrock, and Witch Bay Formation (metavolcanics). Reinvestigation of the geology of the group has shown that the basal clastics of the Wagita Formation (0–150 m) unconformably overlie the Marmion Complex (a massive tonalite – tonalite gneiss terrane, 3 Ga old). Overlying the basal elastics is the Mosher Carbonate (0–500 m), containing diverse stromatolite morphologies. Extensive zones of carbonate breccia occur adjacent to fault zones and mafic dykes. Stratigraphically above the Mosher Carbonate is the Jolliffe Ore Zone (100–400 m), which is divided into a lower Manganiferous Paint Rock Member and an upper Goethite Member. Within the Jolliffe Ore Zone thin layers of "Buckshot Ore" occur. These are horizons of haematitic pisolites and fragments, set in a lighter ferruginous matrix of kaolinite and gibbsite. Overlying the Jolliffe Ore Zone is the Dismal Ashrock, a dominantly high-Mg pyroclastic rock (22% MgO) with minor interbedded lava flows (15% MgO). In contact with the Dismal Ashrock are the metavolcanics of the Witch Bay Formation. This juxtaposition is not exposed in the Steep Rock mine section, and the Witch Bay Formation may be separated from the Dismal Ashrock by a structural break. The Witch Bay Formation is only provisionally included in the Steep Rock Group.The group is interpreted as a sequence deposited in an extensional or rifting environment. The unconformity has regional significance, and it may be possible to define an extensive cratonic nucleus of 3 Ga or older age in northwest Ontario.

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11

Catuneanu, Octavian. "Flexural partitioning of the Late Archaean Witwatersrand foreland system, South Africa." Sedimentary Geology 141-142 (June 2001): 95–112. http://dx.doi.org/10.1016/s0037-0738(01)00070-7.

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12

Mueller, W. U., and P. L. Corcoran. "Late-orogenic basins in the Archaean Superior Province, Canada: characteristics and inferences." Sedimentary Geology 120, no. 1-4 (September 1998): 177–203. http://dx.doi.org/10.1016/s0037-0738(98)00032-3.

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13

van der Westhuizen, W. A., N. J. Grobler, J. C. Loock, and E. A. W. Tordiffe. "Raindrop imprints in the Late Archaean-Early Proterozoic Ventersdorp Supergroup, South Africa." Sedimentary Geology 61, no. 3-4 (February 1989): 303–9. http://dx.doi.org/10.1016/0037-0738(89)90064-x.

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14

Svetova, A. I., and S. A. Svetov. "The stratigraphical boundary between the lower and upper Lopian (upper Archaean) in central Karelia." GFF 118, sup004 (October 1996): 27. http://dx.doi.org/10.1080/11035899609546296.

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15

Els, B. G. "The auriferous late Archaean sedimentation systems of South Africa: unique palaeo-environmental conditions?" Sedimentary Geology 120, no. 1-4 (September 1998): 205–24. http://dx.doi.org/10.1016/s0037-0738(98)00033-5.

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16

DiMARCO, MICHAEL J., and DONALD R. LOWE. "Petrography and provenance of silicified early Archaean volcaniclastic sandstones, eastern Pilbara Block, Western Australia." Sedimentology 36, no. 5 (October 1989): 821–36. http://dx.doi.org/10.1111/j.1365-3091.1989.tb01748.x.

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17

Donaldson, J. Allan, and Eric A. de Kemp. "Archaean quartz arenites in the Canadian Shield: examples from the Superior and Churchill Provinces." Sedimentary Geology 120, no. 1-4 (September 1998): 153–76. http://dx.doi.org/10.1016/s0037-0738(98)00031-1.

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18

Krapez, Bryan. "Sequence stratigraphy of the Archaean supracrustal belts of the Pilbara Block, Western Australia." Precambrian Research 60, no. 1-4 (January 1993): 1–45. http://dx.doi.org/10.1016/0301-9268(93)90043-2.

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19

Henriksen, N., J. D. Friderichsen, R. A. Strachan, N. J. Soper, and A. K. Higgins. "Caledonian and pre-Caledonian geology of the region between Grandjean Fjord and Bessel Fjord (75°–76°N), North-East Greenland." Rapport Grønlands Geologiske Undersøgelse 145 (December 31, 1989): 90–97. http://dx.doi.org/10.34194/rapggu.v145.8084.

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The area between Grandjean Fjord and Bessel Fjord was the focus in 1988 of regional geological investigations and 1:500000 mapping during the North-East Greenland project (Henriksen, 1989). The greater part of the area forms part of the East Greenland Caledonides and can be divided into three distinct rock groups: infracrustal gneisses and granites of possibie Archaean or early Proterozoic origin; a metasedimentary sequence which has probably suffered both mid-Proterozoic and Caledonian migmatisation and metamorphism; and the late Proterozoic Eleonore Bay Group, a thick sedimentary sequence which has undergone amphibolite facies Caledonian metamorphism in its lower parts and is intruded by Caledonian granites. Aspects of the stratigraphy and sedimentology of the Eleonore Bay Group are described by Sønderholm et al. (1989); only the structures affecting the sequence are described here.

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20

Toulkeridis, Theofilos, Norbert Clauer, Alfred Kröner, Thomas Reimer, and Wolfgang Todt. "Characterization, provenance, and tectonic setting of Fig Tree greywackes from the Archaean Barberton Greenstone Belt, South Africa." Sedimentary Geology 124, no. 1-4 (March 1999): 113–29. http://dx.doi.org/10.1016/s0037-0738(98)00123-7.

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21

RING, UWE, HILDE L. SCHWARTZ, TIMOTHY G. BROMAGE, and CHARLES SANAANE. "Kinematic and sedimentological evolution of the Manyara Rift in northern Tanzania, East Africa." Geological Magazine 142, no. 4 (July 2005): 355–68. http://dx.doi.org/10.1017/s0016756805000841.

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We describe the stratigraphical/sedimentological and structural evolution of the Manyara Rift in the Tanzania Divergence Zone, East Africa. The rift-related Manyara Beds on the shoaling side of the Manyara Rift were deposited between <1.7 and 0.4 Ma and can be separated into a lacustrine lower member and a fluvial upper member. The transition from lacustrine to fluvial sedimentation at ∼ 0.7 Ma appears to be related to a southward shift of major rift faulting. Fault geometry and the kinematics of the faults are consistent with major faulting during NE/E-directed extension. There is also evidence for other extensional directions including radial extension, which might be caused by magmatic activity and/or might reflect oblate strain symmetry where the East African Rift propagated into the Archaean Tanzania Craton and associated termination of rifting caused an increase in the strained area.

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22

ELS, B. G. "Anomalous pebble size variation in an erosive, Late Archaean braided stream: the Middelvlei gold placer, Witwatersrand, South Africa." Sedimentology 40, no. 1 (February 1993): 41–52. http://dx.doi.org/10.1111/j.1365-3091.1993.tb01089.x.

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23

BARRETT, T. J., and P. W. FRALICK. "Turbidites and iron formations, Beardmore-Geraldton, Ontario: application of a combined ramp/fan model to Archaean clastic and chemical sedimentation." Sedimentology 36, no. 2 (April 1989): 221–34. http://dx.doi.org/10.1111/j.1365-3091.1989.tb00604.x.

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24

England, Gavin L., Birger Rasmussen, Bryan Krapez, and David I. Groves. "Palaeoenvironmental significance of rounded pyrite in siliciclastic sequences of the Late Archaean Witwatersrand Basin: oxygen-deficient atmosphere or hydrothermal alteration?" Sedimentology 49, no. 6 (December 2002): 1133–56. http://dx.doi.org/10.1046/j.1365-3091.2002.00479.x.

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25

Corcoran, P. L., W. U. Mueller, and E. H. Chown. "Climatic and tectonic influences on fan deltas and wave- to tide-controlled shoreface deposits: evidence from the Archaean Keskarrah Formation, Slave Province, Canada." Sedimentary Geology 120, no. 1-4 (September 1998): 125–52. http://dx.doi.org/10.1016/s0037-0738(98)00030-x.

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26

Thomson, B. "Petrology and stratigraphy of some texturally well preserved thin komatiites from Kambalda, Western Australia." Geological Magazine 126, no. 3 (May 1989): 249–61. http://dx.doi.org/10.1017/s0016756800022342.

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AbstractArchaean komatiite volcanics at Kambalda, Western Australia have been metamorphosed to upper greenschist–lower amphibolite grade and have experienced intense though heterogeneously developed polyphase deformation. Despite this, preservation of igneous textural features is often good, particularly in areas which underwent only ‘static style’ metamorphism. Thin lavas from the Tripod Hill Member of the Kambalda Komatiite Formation over the western margin of the Hunt nickel shoot display textural elements and facies variations which are virtually identical to those found in fresher thin komatiite sequences in other Archaean greenstone belts. Four principal flow profile (facies) types are defined, comprising nine subtypes. These represent stages in a facies continuum, ranging from ‘mature’ profiles which comprise thick spinifex textured tops and close packed cumulate bases through to massive, jointed ‘immature’ profiles devoid of mesoscopic spinifex texture. The causes of textural diversity within and between profiles are many and complex. However, facies variations can be attributed mainly to the effects of lava velocity at the time of major heat loss, combined with relative lateral position within any flow. The most mature textural (and geochemical) profiles developed in parts of lavas which had become ponded prior to major heat loss, whereas the least evolved profiles developed along the lateral margins (levees) of moving lavas. The study area komatiites occur as alternating stacks of flows of similar type. This stratigraphy records temporal and spatial shifts in the locus of lava ponding over the western margin of the Hunt nickel shoot. Such shifts may have been caused by irregularities in the underlying volcanic topography and/or by synvolcanic faulting and subsidence.

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27

Wilson, Allan H., and J. Adrian Versfeld. "The early Archaean Nondweni greenstone belt, southern Kaapvaal Craton, South Africa, Part I. Stratigraphy, sedimentology, mineralization and depositional environment." Precambrian Research 67, no. 3-4 (May 1994): 243–76. http://dx.doi.org/10.1016/0301-9268(94)90012-4.

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28

CHADWICK, BRIAN. "The stratigraphy of a sheet of supracrustal rocks within high-grade orthogneisses and its bearing on Late Archaean structure in southern West Greenland." Journal of the Geological Society 147, no. 4 (July 1990): 639–52. http://dx.doi.org/10.1144/gsjgs.147.4.0639.

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29

Barnhart, Elliott P., Kara Bowen De León, Bradley D. Ramsay, Alfred B. Cunningham, and Matthew W. Fields. "Investigation of coal-associated bacterial and archaeal populations from a diffusive microbial sampler (DMS)." International Journal of Coal Geology 115 (August 2013): 64–70. http://dx.doi.org/10.1016/j.coal.2013.03.006.

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30

Brooks, Kent. "The young Earth and the story of the early Archaean rocks of West Greenland." Geology Today 27, no. 1 (January 2011): 15–19. http://dx.doi.org/10.1111/j.1365-2451.2011.00778.x.

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31

Lin, Genmei, Jianguo Lu, Kunwen Luo, Yunxin Fang, Jiawei Liu, Xiang Ji, Shutong Ge, Jia Liu, and Ming Su. "Characterization of bacterial and archaeal community structure in deep subsurface sediments in the Shenhu area, northern South China Sea." Marine and Petroleum Geology 136 (February 2022): 105468. http://dx.doi.org/10.1016/j.marpetgeo.2021.105468.

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32

Gardiner, N. J., J. A. Mulder, C. L. Kirkland, T. E. Johnson, and O. Nebel. "Palaeoarchaean TTGs of the Pilbara and Kaapvaal cratons compared; an early Vaalbara supercraton evaluated." South African Journal of Geology 124, no. 1 (March 1, 2021): 37–52. http://dx.doi.org/10.25131/sajg.124.0010.

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Abstract The continental crust that dominates Earth’s oldest cratons comprises Eoarchaean to Palaeoarchaean (4.0 to 3.2 Ga) felsic intrusive rocks of the tonalite-trondhjemite-granodiorite (TTG) series. These are found either within high-grade gneiss terranes, which represent Archaean mid-continental crust, or low-grade granite-greenstone belts, which represent relic Archaean upper continental crust. The Palaeoarchaean East Pilbara Terrane (EPT), Pilbara Craton, Western Australia, and the Barberton Granite-Greenstone Belt (BGGB), Kaapvaal Craton, southern Africa, are two of the best exposed granite-greenstone belts. Their striking geological similarities has led to the postulated existence of Vaalbara, a Neoarchaean-Palaeoproterozoic supercraton. Although their respective TTG domes have been compared in terms of a common petrogenetic origin reflecting a volcanic plateau setting, there are important differences in their age, geochemistry, and isotopic profiles. We present new zircon Hf isotope data from five granite domes of the EPT and compare the geochemical and isotopic record of the Palaeoarchaean TTGs from both cratons. Rare >3.5 Ga EPT evolved rocks have juvenile εHf(t) requiring a chondritic source. In contrast, younger TTG domes developed via 3.5 to 3.4 and 3.3 to 3.2 Ga magmatic supersuites with a greater range of εHf(t) towards more depleted and enriched values, trace element signatures requiring an enriched source, and xenocrystic zircons that reflects a mixed source to the TTGs, which variously assimilates packages of older felsic crust and a more juvenile mafic source. EPT TTG domes are composite and record multiple pulses of magmatism. In comparison, BGGB TTGs are less geochemically enriched than those of the EPT and have different age profiles, hosting coeval magmatic units. Hafnium isotopes suggest a predominantly juvenile source to 3.2 Ga northern Barberton TTGs, limited assimilation of older evolved crust in 3.4 Ga southern Barberton TTGs, but significant assimilation of older (Hadean-Eoarchaean) crust in the ca. 3.6 Ga TTGs of the Ancient Gneiss Complex. The foundation of the EPT is younger than that for the oldest components of the Eastern Kaapvaal. Although the broader prevailing Palaeoarchaean geologic framework in which these two cratons formed may reflect similar a geodynamic regime, the superficial similarities in dome structures and stratigraphy of both cratonic terranes is not reflected in their geochemical and age profiles. Both the similarities and the differences between the crustal histories of the two cratons highlights that they are formed from distinct terranes with different ages and individual evolutionary histories. Vaalbara sensu lato represents typical Palaeoarchaean cratonic crust, not in the sense of a single homogeneous craton, but one as diverse as the continents are today.

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Aucelli, Pietro, Vincenzo Amato, Massimo Cesarano, Gerardo Pappone, Carmen Rosskopf, Elda Ermolli, and Fabio Scarciglia. "New morphostratigraphic and chronological constraints for the Quaternary paleosurfaces of the Molise Apennine (southern Italy)." Geologica Carpathica 62, no. 1 (February 1, 2011): 17–26. http://dx.doi.org/10.2478/v10096-011-0002-2.

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New morphostratigraphic and chronological constraints for the Quaternary paleosurfaces of the Molise Apennine (southern Italy)The Molise Apennines feature numerous relicts of paleosurfaces, mostly of erosional origin, which represent the remnants of gently-rolling ancient landscapes now hanging at different altitudes above the local base-levels of erosion. Their genesis can be related to prolonged periods of relative tectonic stability alternating with periods of uplift, or to the interplay between steady tectonic uplift and climatic fluctuations. Four orders of paleosurfaces were recognized: I (> 1,100 m a.s.l.), II (900-1,000 m a.s.l.), III (750-850 m a.s.l.), IV (600-720 m a.s.l.). The most ancient orders (I and II) are cut into the bedrock and are located at the top of the Matese and Montagnola di Frosolone massifs. The youngest paleosurfaces (III—IV), partially cut into Quaternary deposits, are found along the valley flanks of the main river systems and within the Boiano, Carpino, Isernia and Sessano intramontane basins. The present study deals with the dating of the Sessano Basin Paleosurface (SBP) which is related to the IV order and is cut into the basin infill. The40Ar/39Ar age of a tephra layer (437 ± 1.9 ka), intercalated at the top of the succession, supported by archaeo-stratigraphic, palynological and paleopedological data, allowed the SBP surface to be constrained to 350-300 ka. The SBP chronological position represents an important morphostratigraphic marker: it is the firstante quemandpost quemdate that allows the chronological position of the other orders of paleosurfaces to be better constrained.

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Bruins, Hendrik J., Johannes van der Plicht, and J. Alexander MacGillivray. "The Minoan Santorini Eruption and Tsunami Deposits in Palaikastro (Crete): Dating by Geology, Archaeology, 14C, and Egyptian Chronology." Radiocarbon 51, no. 2 (2009): 397–411. http://dx.doi.org/10.1017/s003382220005579x.

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Deposits from the Minoan Santorini (Thera) eruption in the eastern Mediterranean region constitute the most important regional stratigraphic marker in the chronological perplexity of the 2nd millennium BCE. Extensive tsunami deposits were discovered in Crete at the Minoan archaeological site of Palaikastro, containing reworked volcanic Santorini ash. Hence, airborne deposition of volcanic ash, probably during the 1st (Plinian) eruption phase, preceded the tsunami, which was apparently generated during the 3rd or 4th phase of the eruption, based on evidence from Thera. Average radiocarbon dates (uncalibrated) of animal bones in the Palaikastro tsunami deposits along the coast (3350 ± 25 BP) and at the inland archaeological site (3352 ± 23 BP) are astoundingly similar to the average 14C date for the Minoan Santorini eruption at Akrotiri on Thera (3350 ± 10 BP). The wiggle-matched 14C date of the eruption in calendar years is 1627–1600 cal BCE. Late Minoan IA pottery is the youngest element in the Palaikastro tsunami deposits, fitting with the LM IA archaeological date for the Santorini eruption, conventionally linked at ~1500 BCE with Dynasty XVIII of the historical Egyptian chronology. The reasons for the discrepancy of 100–150 yr between 14C dating and Egyptian chronology for part of the 2nd millennium BCE are unknown. 14C dates from Tell el-Dabca in the eastern Nile Delta show that the 14C age of the Santorini eruption matches with 14C results from 18th Dynasty strata C3 and C2, thereby confirming grosso modo the conventional archaeo-historical correlations between the Aegean and Egypt. We propose that a dual dating system is used in parallel: (1) archaeological material-cultural correlations linked to Egyptian chronology; (2) 14C dating. Mixing of dates from the 2 systems may lead to erroneous archaeological and historical correlations. A “calibration curve” should be established between Egyptian chronology and 14C dating for the 2nd millennium BCE, which may also assist to resolve the cause of the discrepancy.

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Chen, Duo Fu, Yong Yang Huang, Xun Lai Yuan, and Lawrence M. Cathles. "Seep carbonates and preserved methane oxidizing archaea and sulfate reducing bacteria fossils suggest recent gas venting on the seafloor in the Northeastern South China Sea." Marine and Petroleum Geology 22, no. 5 (May 2005): 613–21. http://dx.doi.org/10.1016/j.marpetgeo.2005.05.002.

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Lysenko, V. I., S. A. Sadykov, and T. V. Mikhailichenko. "Hydrothermal-bacterial structures with a brachiopod fauna on the surface of Tessel paleovolcano (South coast of Crimea)." LITHOSPHERE (Russia) 22, no. 4 (September 3, 2022): 497–511. http://dx.doi.org/10.24930/1681-9004-2022-22-4-497-511.

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Research subject. For the first time, the results of a study of hydrothermal-bacterial carbonate structures and a shell bank of brachiopods on the surface of the effusive sequence of the Late Triassic Tessel paleovolcano are presented. Methods. Petrographic thin sections were studied using an Olympus BX 5 microscope with an Olympus DP 12 camera. Geochemical investigations were performed according to the conventional methodology by an inductively coupled plasma mass spectrometer (ICP-MS). The isotopic composition of carbon was determined by isotope ratio mass spectrometry (IRMS) by a Deltaplus Advantage instrument. The mass spectrometer was paired with an EA Flash1112 analyzer and a TC/EA convector. When measuring, the NBS-19, NBS-18, and IAEA-C-3 standards were used. Results. The data obtained on the geology, geochemistry, and isotopic composition of the studied materials confirm the existence of a symbiosis between brachiopods and protozoa. The primary formation of organic matter and carbonate of bacterial structures occurred due to the processing of paleofluids by the community of bacteria and archaea. These organisms created carbonate, sulfide and organic matter in a suboxide environment of hydrogen sulfide and methane. The biocenosis of the shell bank of brachiopods was characterized by a poor taxonomic composition and a high biological productivity. The formation of a shell bank of brachiopods with bacterial carbonate edifices took place during the period of volcanic activity and continued during breaks in eruptions. The results of geochemistry and the carbon isotopic composition of the carbonate of bacterial buildups confirm the deep nature of the paleofluids. The Norian age of paleovolcanism was determined from finds on the surface of the terrigenous- volcanic sequence of brachiopods Worobiella ex gr. caucasica Dagys and ammonite Megaphyllites insectus (Mojsisovics). Conclusions. According to geological features, the material of the shell bank of brachiopods with bacterial carbonate structures on the surface of the Tessel paleovolcano belongs to the ancient hydrocarbon seeps-carbonate. Based on their genesis and formation material, these formations should be referred to as Triassic methanoliths. Signs of allocation of similar formations in other time intervals and regions are given. Emissions of fluids with hydrogen sulfide and methane by the Tessel paleovolcano in the Late Triassic may have been related to the causes of the “global extinction”.

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García Martínez, Daniel, Mathieu Duval, Jianxin Zhao, Yuexing Feng, Rachel Wood, Rosa Huguet, Gabriel Cifuentes-Alcobendas, Carlos A. Palancar, and Pedro R. Moya-Maleno. "Los Villares locality (Ruidera, Castilla-La Mancha, Spain): a new Middle Pleistocene fossil assemblage from the Southern Iberian Plateau with possible evidence of human activity." Cuaternario y Geomorfología 36, no. 1-2 (June 27, 2022): 7–35. http://dx.doi.org/10.17735/cyg.v36i1-2.90422.

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We present the discovery of a Middle Pleistocene fossil assemblage at Los Villares (Ruidera, Ciudad Real, Castilla-La Mancha), which has possible evidence of associated human activity. The potential of the site has been evaluated through multidisciplinary research including taxonomy, anatomy, deep learning, and direct dating of fossil remains. A surface study carried out in 2017, over a very limited area (2 m2) on the slope of one of the Ruidera lakes led to the discovery of more than 50 fossil specimens, including cranial (mainly teeth) and postcranial remains. This rich assemblage is dominated by the remains of Caprinae, although the presence of some small or medium carnivore remains also stands out. The identification of a cut mark, tested with Convolutional Neural Networks, suggests the presence of human activity within the bone assemblage. Several fossils were directly dated using a multi-technique approach involving radiocarbon, U-Th, and ESR methods. The results constrain the fossil assemblage to between 300 ka and 400 ka, positioning Los Villares as one of the first Middle Pleistocene localities identified in the Upper Guadiana basin, on the Southern edge of the Southern Iberian Plateau. These promising initial results show the great potential of the site to contribute to filling a gap of knowledge in the Pleistocene archaeo-paleontological record of the Iberian Peninsula. Nevertheless, we also acknowledge the need for systematic excavations in the future, not only to obtain a better idea of the lateral and stratigraphic extension of the fossil assemblage and its complete taxonomic composition but to confirm the human presence at the site.

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Usoltseva, Olga, and Elena Kozlovskaya. "Studying local earthquakes in the area Baltic-Bothnia Megashear using the data of the POLENET/LAPNET temporary array." Solid Earth 7, no. 4 (July 18, 2016): 1095–108. http://dx.doi.org/10.5194/se-7-1095-2016.

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Abstract. Earthquakes in areas within continental plates are still not completely understood, and progress on understanding intraplate seismicity is slow due to a short history of instrumental seismology and sparse regional seismic networks in seismically non-active areas. However, knowledge about position and depth of seismogenic structures in such areas is necessary in order to estimate seismic hazard for such critical facilities such as nuclear power plants and nuclear waste deposits. In the present paper we address the problem of seismicity in the intraplate area of northern Fennoscandia using the information on local events recorded by the POLENET/LAPNET (Polar Earth Observing Network) temporary seismic array during the International Polar Year 2007–2009. We relocate the seismic events using the program HYPOELLIPS (a computer program for determining local earthquake hypocentral parameters) and grid search method. We use the first arrivals of P waves of local events in order to calculate a 3-D tomographic P wave velocity model of the uppermost crust (down to 20 km) for a selected region inside the study area and show that the velocity heterogeneities in the upper crust correlate well with known tectonic units. We compare the position of the velocity heterogeneities with the seismogenic structures delineated by epicentres of relocated events and demonstrate that these structures generally do not correlate with the crustal units formed as a result of crustal evolution in the Archaean and Palaeoproterozoic. On the contrary, they correlate well with the postglacial faults located in the area of the Baltic-Bothnia Megashear (BBMS). Hypocentres of local events have depths down to 30 km. We also obtain the focal mechanism of a selected event with good data quality. The focal mechanism is of oblique type with strike-slip prevailing. Our results demonstrate that the Baltic-Bothnia Megashear is an important large-scale, reactivated tectonic structure that has to be taken into account when estimating seismic hazard in northern Fennoscandia.

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"Chapter 1 Introduction." Geological Society, London, Memoirs 26, no. 1 (2002): 1–10. http://dx.doi.org/10.1144/gsl.mem.2002.026.01.01.

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The Lewisian outcrops at Gairloch and Loch Maree have long been regarded as key areas in the Lewisian complex of NW Scotland because of the presence of the supracrustal rocks of the Palaeoproterozoic Loch Maree Group enclosed within the Archaean gneisses. Long before the age of this Group was known, attention was focused on these areas because the existence of metasedimentary rocks offered the possibility of establishing a stratigraphy within the Lewisian complex. Until relatively recently, Lewisian 'stratigraphy' was based entirely on the relative ages of igneous and metamorphic events.The early Geological Survey workers debated whether the acid gneisses represented deformed granites which intruded the metase-diments or whether they represented an older basement on which the sediments had been laid down. During the discussion that followed the reading of the classic paper on the Lewisian by Sutton & Watson (1951), C. E. Tilley proposed that the critical region for interpreting Lewisian stratigraphy was neither Loch Laxford nor Loch Torridon, but Loch Maree and Gairloch.The pioneering work by Sutton & Watson on the Lewisian complex of NW Scotland stimulated the study of Precambrian basement complexes worldwide. Their methods offered the expectation that dyke swarms and other igneous suites could be used as stratigraphic markers to construct a chronology of tectono-thermal events in what seemed hopelessly confusing gneiss terrains.The Lewisian complex of NW Scotland is part of a widespread system of Palaeoproterozoic orogenic belts in the North Atlantic region. In a recent palaeomagnetic reconstruction of Laurentia and Baltica during

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Henriksen, Niels, A. K. Higgins, Feiko Kalsbeek, and T. Christopher R. Pulvertaft. "Greenland from Archaean to Quaternary. Descriptive text to the Geological map of Greenland, 1:2 500 000." GEUS Bulletin, December 29, 2000, 2–93. http://dx.doi.org/10.34194/ggub.v185.5197.

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NOTE: This monograph was published in a former series of GEUS Bulletin. Please use the original series name when citing this monograph, for example: Henriksen, N., Higgins, A., Kalsbeek, F., & Pulvertaft, T. C. R. (2000). Greenland from Archaean to Quaternary. Descriptive text to the Geological map of Greenland, 1:2 500 000. Geology of Greenland Survey Bulletin, 185, 2-93. https://doi.org/10.34194/ggub.v185.5197 _______________ The geological development of Greenland spans a period of nearly 4 Ga, from the earliest Archaean to the Quaternary. Greenland is the largest island in the world with a total area of 2 166 000 km2, but only c. 410 000 km2 are exposed bedrock, the remaining part being covered by an inland ice cap reaching over 3 km in thickness. The adjacent offshore areas underlain by continental crust have an area of c. 825 000 km2. Greenland is dominated by crystalline rocks of the Precambrian shield, which formed during a succession of Archaean and early Proterozoic orogenic events and which stabilised as a part of the Laurentian shield about 1600 Ma ago. The shield area can be divided into three distinct types of basement provinces: (1) Archaean rocks (3100-2600 Ma old, with local older units) almost unaffected by Proterozoic or later orogenic activity; (2) Archaean terraines reworked during the early Proterozoic around 1850 Ma ago; and (3) terraines mainly composed of juvenile early Proterozoic rocks (2000-1750 Ma old). Subsequent geological developments mainly took place along the margins of the shield. During the later Proterozoic and throughout the Phanerozoic major sedimentary basins formed, notably in North and North-East Greenland, and in places accumulated sedimentary successions which reached 10-15 km in thickness. Palaeozoic orogenic activity affected parts of these successions in the Ellesmerian fold belt of North Greenland and the East Greenland Caledonides; the latter also incorporates reworked Precambrian crystalline basement complexes. Late Palaeozoic and Mesozoic sedimentary basins developed along the continent-ocean margins in North, East and West Greenland and are now preserved both onshore and offshore. Their development was closely related to continental break-up with formation of rift basins. Initial rifting in East Greenland in latest Devonian to earliest Carboniferous time and succeeding phases culminated with the opening of the North Atlantic in the late Paleocene. Sea-floor spreading was accompanied by extrusion of Tertiary plateau basalts in both central West and central and southern East Greenland. During the Quaternary Greenland was almost completely covered by ice sheets, and the present Inland Ice is a relic of the Pleistocene ice ages. Vast amounts of glacially eroded detritus were deposited on the continental shelves offshore Greenland. Mineral exploitation in Greenland has so far mainly been limited to one cryolite mine, two lead-zinc deposits and one coal deposit. Current prospecting activities in Greenland are concentrated on the gold, diamond and lead-zinc potential. The hydrocarbon potential is confined to the major Phanerozoic sedimentary basins, notably the large basins offshore East and West Greenland. While proven reserves of oil or gas have yet to be found, geophysical data combined with extrapolations from onshore studies have revealed a considerable potential for offshore oil and gas. The description of the map has been prepared with the needs of the professional geologist in mind; it requires a knowledge of geological principles but not previous knowledge of Greenland geology. Throughout the text reference is made to the key numbers in the map legend indicated in square brackets [ ] representing geological units (see Legend explanation, p. 79), while a Place names register (p. 83) and an Index (p. 87) include place names, geological topics, stratigraphic terms and units found in the legend. The extensive reference list is intended as a key to the most relevant information sources.

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Garde, Adam A. "Accretion and evolution of an Archaean high-grade grey gneiss – amphibolite complex: the Fiskefjord area, southern West Greenland." GEUS Bulletin, October 10, 1997, 1–115. http://dx.doi.org/10.34194/ggub.v179.5075.

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NOTE: This monograph was published in a former series of GEUS Bulletin. Please use the original series name when citing this series, for example: Garde, A. A. 1997: Accretion and evolution of an Archaean high-grade grey gneiss – amphibolite complex: the Fiskefjord area, southern West Greenland. Geology of Greenland Survey Bulletin 177, 115 pp. _______________ The Fiskefjord area in southern West Greenland, part of the Akia tectono-stratigraphic terrane, comprises a supracrustal association and two groups of grey quartzo-feldspathic orthogneises c. 3200 and 3000 Ma old. The supracrustal association forms layers and enclaves in grey gneiss and may comprise two or more age groups. Homogeneous amphibolite with MORB-like but LIL element enriched tholeiitic composition predominates; part, associated with cumulate noritic and dunitic rocks, represents fragments of layered complexes. Heterogeneous amphibolite of likely submarine volcanic origin, (basaltic) andesitic amphibolite, leucogabbro-anorthosite, and minor pelitic metasediment occur. Disruption by magmatic and tectonic events and geochemical alteration have obscured primary origin: the supracrustal association may represent oceanic crust. Grey orthogneiss of the tonalite-trondhjemite-granodiorite (TTG) association was generated during continental accretion at c. 3000 Ma, most likely by partial melting of wet and hot tholeiitic basaltic rocks subducted in a convergent plate setting. Most dioritic gneiss is c. 220 Ma older. A 3040 Ma dioritic to tonalitic phase, enriched in P2O5 , Ba, Sr, K, Pb, Rb and LREE, probably was derived from metasomatised mantle. Intense deformation and metamorphism accompanied the 3000 Ma magmatic accretion.Thrusts along amphibolite-orthogneiss contacts were succeeded by large recumbent isoclines, upright to overturned folds, and local domes with granitic cores. Syntectonic granulite facies metamorphism is thought to be due to heat accumulation by repeated injection of tonalitic magma. Strong ductile deformation produced steep linear belts before the thermal maximum ceased, whereby folds were reorientated into upright south-plunging isoclines. Two large TTG complexes were then emplaced, followed by granodiorite and granite. Post-kinematic diorite plugs with unusually high MgO, Cr and Ni, and low LIL and immobile incompatible element contents, terminated the 3000 Ma accretion. Hybrid border zones and orbicular textures suggest rapid crystallisation from superheated magma. The diorites most likely formed from ultramafic magma contaminated with continental crust. Widespread high-grade retrogression preserved a granulite facies core in the south-west; to the east the retrogressed gneiss grades into amphibolite facies gneiss not affected by granulite facies metamorphism and retrogression. LIL elements were depleted during granulite facies metamorphism and reintroduced during retrogression, probably transported in anatectic silicate melts and in fluids. Rb-Sr isotope data, and relationships between retrogression, high-strain zones and granite emplacement, show that retrogression took place shortly after the granulite facies metamorphism, before terrane assembly at c. 2720 Ma, probably by movement of melts and fluids into the upper, marginal zone of granulite facies rocks from deeper crust still being dehydrated. Retrogression during Late Archaean terrane assembly was in narrow reactivated zones of ductile deformation; in the Proterozoic it occurred with faulting and dyke emplacement.Geochemical data are presented for Early Proterozoic high-Mg and mafic dykes. A rare 2085 Ma microgranite dyke strongly enriched in incompatible trace elements was formed by partial anatexis of Archaean continental crust.

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Rasmussen, Henrik, and Lars Frimodt Pedersen. "Stratigraphy, structure and geochemistry of Archaean supracrustal rocks from Oqaatsut and Naajaat Qaqqaat, north-east Disko Bugt, West Greenland." GEUS Bulletin, July 22, 1999, 65–78. http://dx.doi.org/10.34194/ggub.v181.5114.

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NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Rasmussen, H., & Frimodt Pedersen, L. (1999). Stratigraphy, structure and geochemistry of Archaean supracrustal rocks from Oqaatsut and Naajaat Qaqqaat, north-east Disko Bugt, West Greenland. Geology of Greenland Survey Bulletin, 181, 65-78. https://doi.org/10.34194/ggub.v181.5114 _______________ Two Archaean supracrustal sequences in the area north-east of Disko Bugt, c. 1950 and c. 800 m in thickness, are dominated by pelitic and semipelitic mica schists, interlayered with basic metavolcanic rocks. A polymict conglomerate occurs locally at the base of one of the sequences. One of the supracrustal sequences has undergone four phases of deformation; the other three phases. In both sequences an early phase, now represented by isoclinal folds, was followed by north-west-directed thrusting. A penetrative deformation represented by upright to steeply inclined folds is only recognised in one of the sequences. Steep, brittle N–S and NW–SE striking faults transect all rock units including late stage dolerites and lamprophyres. Investigation of major- and trace-element geochemistry based on discrimination diagrams for tectonic setting suggests that both metasediments and metavolcanic rocks were deposited in an environment similar to a modern back-arc setting.

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Runge, Eric A., Jan‐Peter Duda, Martin J. Van Kranendonk, and Joachim Reitner. "Earth’s oldest tsunami deposit? Early Archaean high‐energy sediments in the ca 3.48 Ga Dresser Formation (Pilbara, Western Australia)." Depositional Record, February 2022. http://dx.doi.org/10.1002/dep2.175.

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