scholarly journals Stratigraphy and age of the Eocene Igtertivâ Formation basalts, alkaline pebbles and sediments of the Kap Dalton Group in the graben at Kap Dalton, East Greenland

2013 ◽  
Vol 61 ◽  
pp. 1-18 ◽  
Author(s):  
Lotte Melchior Larsen ◽  
Erik Vest Sørensen ◽  
W. Stuart Watt ◽  
Asger Ken Pedersen ◽  
Robert A. Duncan
Keyword(s):  
Field Work ◽  
Lava Flows ◽  
Radiometric Dating ◽  
Dyke Swarm ◽  
Geological Time ◽  
Geological Time Scale ◽  
The North ◽  
Northward Propagation ◽  
Volcanic Succession ◽  
Good Agreement

A NE–SW-trending graben at Kap Dalton on the Blosseville Kyst contains an at least 600 m thick succession of Eocene basalt lavas and sediments. The succession has been investigated by new field work, geochemical analysis and radiometric dating by the 40Ar-39Ar incremental heating method. The results show that the volcanic succession comprises about 220 m of the uppermost plateau basalt formation, the Skrænterne Formation. This is separated from the overlying lava flows of the Igtertivâ Formation by 7 m of sediments that represent a period of around six million years. The two formations can be distinguished by different trace element ratios. The Igtertivâ Formation comprises an at least 300 m thick main succession of flows dated to 49.09 ± 0.48 Ma, overlain by sediments of the Bopladsdalen Formation. A basal conglomerate in the sediments contains pebbles of alkaline igneous rocks of which three were dated at 49.17 ± 0.35 Ma, 47.60 ± 0.25 Ma, and 46.98 ± 0.24 Ma. The sediments are thus younger than 47 Ma. Above 30 m of sediments occur two Igtertivâ Formation lava flows dated to 43.77 ± 1.08 Ma. The overlying sediments of the Bopladsdalen and Krabbedalen Formations are therefore not older than about 44 Ma and palynological evidence shows that they are also not much younger than this. Use of the Geological Time Scale 2012 has resulted in good agreement between radiometric and palynological ages. The Igtertivâ Formation lava flows were fed from a regional coast-parallel dyke swarm indicating a new rifting episode at 49–44 Ma. This coincides with a major mid-Eocene plate reorganisation event in the North Atlantic and the start of northward-propagation of the Reykjanes Ridge through the continent. The Igtertivâ rift may have been directly instrumental for the initiation of this process.

scholarly journals Middle Triassic trachytic lava flows associated with coeval dyke swarm in the North Patagonian Massif: A postorogenic magmatism related to extensional collapse of the Gondwanide orogen

2017 ◽  
Vol 75 ◽  
pp. 134-143 ◽  
Author(s):  
Santiago N. González ◽  
Gerson A. Greco ◽  
Ana M. Sato ◽  
Eduardo J. Llambías ◽  
Miguel A.S. Basei ◽  
...  
Keyword(s):  
Middle Triassic ◽  
Lava Flows ◽  
Dyke Swarm ◽  
The North ◽  
Extensional Collapse

scholarly journals Calibrating Mid-Permian to Early Triassic Khuff sequences with orbital clocks

GeoArabia ◽  
2010 ◽  
Vol 15 (3) ◽  
pp. 171-206 ◽  
Author(s):  
Moujahed I. Al-Husseini ◽  
Robley K. Matthews
Keyword(s):  
Time Scale ◽  
Radiometric Dating ◽  
Arabian Plate ◽  
Early Triassic ◽  
Geological Time ◽  
Triassic Boundary ◽  
Geological Time Scale ◽  
Type Section ◽  
Geologic Time Scale ◽  
Permian Triassic Boundary

ABSTRACT The Middle East Geologic Time Scale (ME GTS) seeks to document and age-calibrate Arabian Plate transgressive-regressive (T-R) depositional sequences using: (1) Geological Time Scale of the International Commission on Stratigraphy (GTS), and (2) Arabian Orbital Stratigraphy time scale (AROS). AROS is based on an orbital-forcing glacio-eustatic model that offers three orbital clocks to date T-R sequences: (1) Stratons @ ca. 405 Ky; (2) Dozons @ ca. 4.86 My (12 stratons); and Orbitons @ ca. 14.58 My (36 stratons, three dozons). The Earth today is in Orbiton 0, which started ca. 1.5 Ma (SB 0); the ages of lower boundaries of orbitons can be estimated with the formula SB n = n × 14.58 + 1.5 Ma. This scheme was used to calibrate the Arabian Plate’s Mid-Permian to Early Triassic Khuff sequences, which contain one of the largest gas-bearing carbonate reservoirs in the World. The Khuff and equivalent formations have been interpreted by several authors in terms of six long-period sequences in outcrop belts and subsurface sections (Khuff sequences KS6 to KS1 in ascending order). Their type sections are briefly reviewed with emphasis on their boundaries, higher-order architecture and stage assignments. The age calibration starts at the basal Khuff Sequence Boundary (Khuff SB, Sub-Khuff Unconformity) defined in a type section in Al Huqf outcrop in Oman. Above the Khuff SB (ca. 268.9 Ma) the type sections of the oldest Khuff sequences KS6 (ca. 268.9–264.0 Ma) and KS5 (ca. 264.0–259.1 Ma) are defined in Oman and interpreted to each consist of twelve subsequences (stratons) with the predicted architecture of two consecutive dozons. By biostratigraphy they span the Mid-Permian (Guadalupian Epoch), Wordian and Capitanian stages. Type-Sequence KS4 (ca. 259.1–254.2 Ma) is defined in Iran and corresponds to the Wuchiapingian Stage. The Iranian type-Khuff Sequence KS3 (ca. 254.2–249.4 Ma) contains nine subsequences (stratons) grouped between two major exposure surfaces. By correlation to the Changhsingian Stage and Permian/Triassic Boundary (PTrB) type section in South China, it is interpreted as a dozon with three missing stratons. Khuff Sequence KS2 (ca. 249.4–247.8 Ma) contains the PTrB with an orbital age of ca. 249.0 Ma, compared to 251.0 ± 0.4 in GTS and 249.0–253.0 Ma by radiometric dating in its type section. Khuff sequences KS2 and KS1 contain 13 subsequences (stratons) between ca. 249.4–244.1 Ma spanning latest Permian and Early Triassic. The boundary of the Khuff with the overlying Sudair Formation, Sudair Sequence Boundary, is defined in Borehole SHD-1 (Central Saudi Arabia) and calibrated at ca. 244.1 Ma falling near the age of the Early/Mid-Triassic Boundary in GTS. The enclosed Chart shows a work-in-progress correlation of the six Khuff sequences across the Arabian Plate.

scholarly journals The East Greenland rifted volcanic margin

2011 ◽  
Vol 24 ◽  
pp. 1-96 ◽  
Author(s):  
C. Kent Brooks
Keyword(s):  
North Atlantic ◽  
Wide Spectrum ◽  
Radiometric Dating ◽  
Dyke Swarm ◽  
Time Interval ◽  
Short Time Interval ◽  
East Greenland ◽  
The North ◽  
The North Atlantic ◽  
Dyke Swarms

The Palaeogene North Atlantic Igneous Province is among the largest igneous provinces in the world and this review of the East Greenland sector includes large amounts of information amassed since previous reviews around 1990. The main area of igneous rocks extends from Kangerlussuaq (c. 67°N) to Scoresby Sund (c. 70°N), where basalts extend over c. 65 000 km2 , with a second area from Hold with Hope (c. 73°N) to Shannon (c. 75°N). In addition, the Ocean Drilling Project penetrated basalt at five sites off South-East Greenland. Up to 7 km thickness of basaltic lavas have been stratigraphically and chemically described and their ages determined. A wide spectrum of intrusions are clustered around Kangerlussuaq, Kialeeq (c. 66°N) and Mesters Vig (c. 72°N). Layered gabbros are numerous (e.g. the Skaergaard and Kap Edvard Holm intrusions), as are under- and oversaturated syenites, besides small amounts of nephelinite-derived products, such as the Gardiner complex (c. 69°N) with carbonatites and silicate rocks rich in melilite, perovskite etc. Felsic extrusive rocks are sparse. A single, sanidine-bearing tuff found over an extensive area of the North Atlantic is thought to be sourced from the Gardiner complex. The province is famous for its coast-parallel dyke swarm, analogous to the sheeted dyke swarm of ophiolites, its associated coastal flexure, and many other dyke swarms, commonly related to central intrusive complexes as in Iceland. The dyke swarms provide time markers, tracers of magmatic evolution and evidence of extensional events. A set of dykes with harzburgite nodules gives unique insight into the Archaean subcontinental lithosphere. Radiometric dating indicates extrusion of huge volumes of basalt over a short time interval, but the overall life of the province was prolonged, beginning with basaltic magmas at c . 60 Ma and continuing to the quartz porphyry stock at Malmbjerg (c. 72°N) at c. 26 Ma. Indeed, activity was renewed in the Miocene with the emplacement of small volumes of basalts of the Vindtoppen Formation to the south of Scoresby Sund. Although the basalts were extruded close to sea level, this part of East Greenland is a plateau raised to c. 2 km, but the timing of uplift is controversial. Superimposed on the plateau is a major dome at Kangerlussuaq. East Greenland presents a rich interplay between magmatic and tectonic events reflecting the birth of the North Atlantic Ocean. It was active over a much longer period (36 Ma) than other parts of the province (5 Ma in the Hebrides, Northern Ireland and the Faroe Islands) and contains a wider range of products, including carbonatites, and felsic rocks tend to be granitic rather than syenitic. As expected, there are many similarities with Iceland, the present-day expression of activity in the province. Differences are readily explained by higher production rates and the thicker lithospheric lid during the early stages of development in East Greenland. The igneous and related activity clearly results from plate-tectonic factors, but the relationship is not understood in detail. In particular, the nature of the underlying mantle processes, primarily the presence or absence of a plume, is still not resolved.

An updated stratigraphic framework for the Georgina Basin, NT and Queensland

2013 ◽  
Vol 53 (2) ◽  
pp. 487 ◽  
Author(s):  
Tegan Smith ◽  
Andrew P Kelman ◽  
Robert Nicoll ◽  
Dianne Edwards ◽  
Lisa Hall ◽  
...  
Keyword(s):  
Sedimentary Rocks ◽  
Hydrocarbon Exploration ◽  
Source Rocks ◽  
Geological Time ◽  
Geological Time Scale ◽  
The Past ◽  
The North ◽  
Stratigraphic Framework ◽  
Southern Central ◽  
Siliciclastic Rock

The Georgina Basin is a Neoproterozoic to Lower Devonian sedimentary basin covering 325,000 km2 of western Queensland and the NT. It is a northwest-southeast-trending extensional basin, with prospective conventional and unconventional hydrocarbon targets in Cambrian and Ordovician carbonate and siliciclastic rock units. The unconventional gas and oil potential of the basin has led to recent exploration interest, although the basin has been relatively less explored in the past. At the southern end of the basin, depocentres contain up to 2.2 km of Cambrian to Devonian sedimentary rocks, overlying Neoproterozoic sedimentary rocks more than 1.5 km thick. The basin succession thins toward the north, where Cambrian sediments overlie the McArthur Basin sediments in the Beetaloo Sub-basin. Biostratigraphic interpretations of the prospective southern, central and eastern regions of the basin have been revised to reflect the 2012 Geological Time Scale (Gradstein, Ogg, Schmitz, and Ogg, 2012), resulting in an updated chronostratigraphic framework for the basin. The revised biostratigraphic interpretations have implications for important hydrocarbon source rocks. For example, the limestone unit in the southern parts of the basin, generally regarded as the Thorntonia Limestone, is of a different age to the type section for this unit, located in the Undilla Sub-basin. Additionally, the basal hot shale of the Arthur Creek Formation is diachronous across the Dulcie and Toko synclines, which may have ramifications for hydrocarbon exploration. This revised chronostratigraphic framework (by Geoscience Australia) for the Georgina Basin provides a baseline for the first basin-wide assessment of the unconventional hydrocarbon potential of the basin.

The Parisian Basin

2005 ◽  
Author(s):  
Yvette Dewolf ◽  
Charles Pomerol
Keyword(s):  
Sedimentary Basins ◽  
Geological Time ◽  
Geological Time Scale ◽  
Massif Central ◽  
North East ◽  
The North ◽  
Geological Map ◽  
Intracratonic Basin ◽  
Definition Of ◽  
Armorican Massif

The Parisian basin is a geographical entity whose limits are easily defined by the Armorican massif, the Massif Central, the Vosges, the Ardennes, and the English Channel. Both Burgundy and Poitou are transitional areas. The Paris basin, a more restrictive term, corresponds according to some geologists (Cavelier and Lorenz 1987) essentially to the Tertiary ‘part’ of the basin: the Île de France and surroundings. The relief of the Parisian basin results from two sets of factors: tectonic and climatic. These have operated from Triassic times until the Pleistocene and have led to the development of a geographically simple whole in its gross structure and form. However, within this framework individual natural regions (or geotypes) may be recognized. The Parisian basin is frequently considered as a model for sedimentary basins, displaying as it does, a classic framework of sedimentary formations (Pomerol 1978; Cavelier and Pomerol 1979; Cavelier et al. 1979; Pomerol and Feugueur 1986; Debrand-Passard 1995). This is evident from the geological map of France, and on the related cross-section. Indeed, the section shows the superposition of strata in a subsiding area, with a maximal thickness (3,200 m) in the Brie country. This arrangement illustrates the geometric definition of the Parisian basin, an intracratonic basin, 600 km in diameter, limited towards the west by the Armorican massif, the south by the Massif Central, the east by the Vosges, and the north-east by the Ardenno-Rhenan massif. The following geological overview is based upon the previously mentioned studies and the geological time scale. However, the analysis of the evolution of these sedimentary areas from Triassic to Neogene shows that the area named as the ‘Parisian basin’ was included in successive palaeogeographies (which were strongly influenced by adjacent seas) and overflowed across the basement regions that now act as the limits of the basin. The chronological order of the geological formations involved in the evolution of the Parisian basin according to Robin et al. (2000) is used in the following text. During the Triassic, the future Parisian basin was a gulf of the German Sea. This sea transgressed westwards and reached the meridian of Paris during the Keuper.

Stratigraphy of the Qasr Al Haj Formation, Fan-gravel Deposits of Quaternary Age, Tripolitania, S.P.L.A.J.

1988 ◽  
Vol 19 ◽  
pp. 123-131 ◽  
Author(s):  
J. M. Anketell ◽  
S. M. Ghellali
Keyword(s):  
Soil Formation ◽  
Alluvial Fan ◽  
Lava Flows ◽  
The Other ◽  
Radiometric Dating ◽  
Basaltic Lava ◽  
Quaternary Deposits ◽  
North West ◽  
The North ◽  
Aeolian Sands

AbstractThe Qasr Al Haj Formation, comprised of alluvial fan gravels and sands with calcrete horizons, is subdivided into five members separated one from the other by surfaces of discontinuity. These surfaces, defined primarily by erosion and soil formation, can be followed northwards into the Jifarah Formation thus allowing detailed correlation of the fan-gravel deposits with the finer fluvio-aeolian sands and silts of the floodplain. Thick deposits of cemented and uncemented gravels at Wadi Ghan contain at least two horizons of basaltic lava flows. Previously reported finds of artifacts from this gravel sequence together with the possibility of radiometric dating of the lavas, may provide a much-needed chronostratigraphic framework for the Quaternary deposits of the north-west Tripolitanian region.

The post-basaltic Palaeogene and Neogene sediments at Kap Dalton and Savoia Halvø, East Greenland

2002 ◽  
pp. 103-110 ◽  
Author(s):  
Michael Larsen ◽  
Stefan Piasecki ◽  
Lars Stemmerik
Keyword(s):  
North Atlantic ◽  
Field Work ◽  
Flood Basalts ◽  
East Greenland ◽  
The North ◽  
Neogene Sediments ◽  
The North Atlantic ◽  
Volcanic Succession ◽  
Palynological Study ◽  
North Atlantic Igneous Province

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Larsen, M., Piasecki, S., & Stemmerik, L. (2002). The post-basaltic Palaeogene and Neogene sediments at Kap Dalton and Savoia Halvø, East Greenland. Geology of Greenland Survey Bulletin, 191, 103-110. https://doi.org/10.34194/ggub.v191.5136 _______________ The Palaeogene flood basalts in East Greenland are part of the North Atlantic Igneous Province (NAIP) formed during continental rifting and opening of the northern North Atlantic (Saunders et al. 1997). Along the Blosseville Kyst in southern and central East Greenland the basalts are exposed onshore from Kangerlussuaq in the south to Scoresby Sund in the north (Larsen et al. 1989). The base of the volcanic succession is exposed at Kangerlussuaq and at Savoia Halvø whereas post-basaltic sediments are found at two isolated localities, Kap Dalton and Savoia Halvø (Fig. 2). These three outcrop areas are thus key sources for biostratigraphic data to constrain the onset and duration of the Palaeogene volcanism in East Greenland, and are widely used in reconstructions of the North Atlantic region during continental break-up (e.g. Clift et al. 1998; Dam et al. 1999). In August 2001 the Geological Survey of Denmark and Greenland (GEUS) carried out field work in the sedimentary successions at Kap Dalton and Savoia Halvø. This was the first visit by geologists to Kap Dalton since 1975, and it is expected that the new data will provide important new biostratigraphic information and help to refine models for the Palaeogene of the North Atlantic. This report, and the palynological study of the sediments immediately below the basalts at Savoia Halvø presented by Nøhr-Hansen & Piasecki (2002, this volume), present the preliminary results of the field work.

scholarly journals Field work on the Nagssugtoqidian boundary north of Angmagssalik and Tertiary igneous rocks of Kialineq and Kap Gustav Holm, East Greenland

1979 ◽  
Vol 95 ◽  
pp. 82-85
Author(s):  
J.S Myers ◽  
H Austrheim ◽  
R.C.O Gill ◽  
B.E Gorman ◽  
D.C Rex
Keyword(s):  
Field Work ◽  
Igneous Rocks ◽  
Dyke Swarm ◽  
Mobile Belt ◽  
North Shore ◽  
Ice Cap ◽  
The North ◽  
Isotope Studies ◽  
Tycho Brahe ◽  
Inland Ice

Work was carried out from the 80 ton cutter Tycho Brahe using 16 ft inflatable rubber dinghies between 24th July and 31st August 1978. In addition, the Nagssugtoqidian boundary was mapped westwards from Kangerdlugssuatsiaq to the inland ice cap by Bell 204 helicopter and part of the Kialineq region was mapped from a Piper Navajo aircraft (fig. 28). The Nagssugtoqidian boundary was examined on the north shore of Kangerdlugssuatsiaq and a section through the northem part of the Nagssugtoqidian mobile belt was mapped along the shores of the upper part of Sermilik by rubber dinghy. Part of the Angmagssalik charnockite complex was examined in detail around Angmagssalik and Kap Dan. The Tertiary plutonic centres of Kialineq and Kap Gustav Holm were mapped in detail as well as the coastal dyke swarm in these regions, and samples were collected from all the main plutonic units for petrology and isotope studies.

Ketilidian structure and the rapakivi suite between Lindenow Fjord and Kap Farvel, South-East Greenland

2000 ◽  
pp. 50-59
Author(s):  
Brian Chadwick ◽  
Adam A. Garde ◽  
John Grocott ◽  
Ken J.W. McCaffrey ◽  
Mike A. Hamilton
Keyword(s):  
Coastal Region ◽  
Field Work ◽  
Natural Environment Research Council ◽  
East Greenland ◽  
The North ◽  
Tectonic Processes ◽  
Field Investigations ◽  
North Eastern ◽  
Bad Weather ◽  
North Eastern Part

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Chadwick, B., Garde, A. A., Grocott, J., McCaffrey, K. J., & Hamilton, M. A. (2000). Ketilidian structure and the rapakivi suite between Lindenow Fjord and Kap Farvel, South-East Greenland. Geology of Greenland Survey Bulletin, 186, 50-59. https://doi.org/10.34194/ggub.v186.5215 _______________ The southern tip of Greenland is underlain by the Palaeoproterozoic Ketilidian orogen (e.g. Chadwick & Garde 1996; Garde et al. 1998a). Field investigations in the summer of 1999 were focused on the structure of migmatites (metatexites) and garnetiferous granites (diatexites) of the Pelite Zone in the coastal region of South-East Greenland between Lindenow Fjord and Kap Farvel (Figs 1, 2). Here, we first address the tectonic evolution in the Pelite Zone in that region and its correlation with that in the Psammite Zone further north. Then, the structure and intrusive relationships of the rapakivi suite in the Pelite Zone are discussed, including particular reference to the interpretation of the controversial outcrop on Qernertoq (Figs 2, 8). Studies of the structure of the north-eastern part of the Julianehåb batholith around Qulleq were continued briefly from 1998 but are not addressed here (Fig. 1; Garde et al. 1999). The field study was keyed to an interpretation of the Ketilidian orogen as a whole, including controls of rates of thermal and tectonic processes in convergent settings. Earlier Survey field work (project SUPRASYD, 1992–1996) had as its principal target an evaluation of the economic potential of the orogen (Nielsen et al. 1993). Ensuing plate-tectonic studies were mainly funded in 1997–1998 by Danish research foundations and in 1999 by the Natural Environment Research Council, UK. The five-week programme in 1999 was seriously disrupted by bad weather, common in this part of Greenland, and our objectives were only just achieved. Telestation Prins Christian Sund was the base for our operations (Fig. 2), which were flown with a small helicopter (Hughes MD-500).

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