Using detrital geochronology to unravel the Proterozoic greater McArthur Basin of Northern Australia

2020 ◽  
Author(s):  
Morgan Blades ◽  
Alan Collins ◽  
Bo Yang ◽  
Cris Cruz ◽  
Eilidh Cassidy ◽  
...  
Keyword(s):  
Detrital Zircon ◽  
Hf Isotope ◽  
The South ◽  
Isotope Data ◽  
The North ◽  
Icp Ms ◽  
North Eastern ◽  
Igneous Activity ◽  
Sedimentary System ◽  
Pine Creek

<p>There is still little known about the occurrence, formation and spatial distribution of long-lived cratonic basins that form during hundreds of millions of years of subsidence. Their histories often span multiple phases of super-continent break-up, dispersal and amalgamation. Each of these phases resulted in the modification of sedimentation rates and drainage within the basins but the broader basin persisted. These changing conditions are recorded in the detrital zircon record, providing a tool for understanding the basin evolution and consequently its palaeogeography.</p><p>The informally termed greater McArthur Basin is a regionally extensive Proterozoic basin that overlies the North Australian Craton. It is a vast sedimentary system that stretches across the northern part of the Northern Territory from north-eastern Western Australia to north-western Queensland. It includes Palaeo- to Mesoproterozoic successions of the McArthur and Birrindudu basins, the Tomkinson Province and likely the Lawn Hill Platform and South Nicholson Basin (to the south-east); all interpreted to be contemporaneous systems. However, the full extent of the greater McArthur Basin sedimentary system is still being unravelled. The basin records nearly one billion years of Earth history, from ca. 1.82 Ga to ca. 0.85 Ma. This sedimentary system temporally overlaps with episodes of Palaeo- to Mesoproterozoic tectonism and igneous activity that affected underlying and adjacent terranes, including the Aileron, Warumpi and Musgrave provinces to the present-day south, Pine Creek Orogen and Arnhem Province to the north, Halls Creek Orogen and Tanami Region to the west, and Mount Isa and Murphy provinces to the east.  </p><p>LA-ICP-MS detrital zircon U–Pb geochronology and Lu–Hf isotope data provide new constraints on the lower sedimentary successions of the McArthur Basin (Tawallah and Katherine River Groups) and demonstrate they are coetaneous with the Tomkinson Province (Tomkinson Creek Group). U–Pb detrital zircon data show major <sup>207</sup>Pb /<sup>206</sup>Pb peaks at ca. 1860 Ma and ca. 2500–2400 Ma in both the McArthur Basin and Tomkinson Province sediments. Combined with Lu–Hf isotope data, the detrital zircon age data from the McArthur Basin show similarities to the Aileron Province (to the south) and magmatic rocks of the Gawler Craton, suggesting that these terranes might be possible source areas. Comparatively, the oldest succession within the Tomkinson Province (Hayward Creek Formation), shows similar spectra to units within the Lawn Hill Platform succession (McNamara Group, Surprise Creek Sandstone and Carrara Range Group) possibly suggesting a correlation between the two areas.</p><p>Here we explore the links between the North Australia Craton and surrounding continents to further elucidate the evolution of this enigmatic basin throughout the Proterozoic. New palaeogeographic reconstructions link the ‘greater’ McArthur basin to the Yanliao Basin and coeval rocks in the North China Craton. The ‘greater’ McArthur basin may also have extended into southern Australia, Laurentia and Siberia as a vast intra-continental gulf (the McArthur-Yanliao Gulf) within the core of the supercontinent Nuna/Colombia.</p>

Taxonomy of Nystiellidae (Caenogastropoda, Epitonioidea) from Brazil, with description of three new species from the South-western Atlantic

2017 ◽  
Vol 98 (7) ◽  
pp. 1619-1644 ◽  
Author(s):  
Alexandre Dias Pimenta ◽  
Bruno Garcia Andrade ◽  
Ricardo Silva Absalão
Keyword(s):  
Rio Grande ◽  
Taxonomic Revision ◽  
South Atlantic ◽  
Shell Morphology ◽  
The South ◽  
Western Atlantic ◽  
North East ◽  
The North ◽  
Eastern Brazil ◽  
North Eastern

A taxonomic revision of the Nystiellidae from Brazil, including samples from the Rio Grande Rise, South Atlantic, was performed based on shell morphology. Five genera and 17 species were recognized. For the richest genus,Eccliseogyra, the three species previously recorded from Brazil were revised:E. brasiliensisandE. maracatu, previously known only from their respective type series, were re-examined. Newly available material ofE. maracatuexpanded the known geographic range of this species to off south-east Brazil.Eccliseogyra nitidais now recorded from north-eastern to south-eastern Brazil, as well as from the Rio Grande Rise. Three species ofEccliseogyraare newly recorded from the South Atlantic:E. monnioti, previously known from the north-eastern Atlantic, occurs off eastern Brazil and on the Rio Grande Rise; its protoconch is described for the first time, confirming its family allocation.Eccliseogyra pyrrhiasoccurs off eastern Brazil and on the Rio Grande Rise, andE. folinioff eastern Brazil. The genusIphitusis newly recorded from the South Atlantic.Iphitus robertsiwas found off northern Brazil, although the shells show some differences from the type material, with less-pronounced spiral keels. Additional new finds showed thatIphitus cancellatusranges from eastern Brazil to the Rio Grande Rise, and Iphitusnotiossp. nov. is restricted to the Rio Grande Rise.Narrimania, previously recorded from Brazil based on dubious records, is confirmed, including the only two living species described for the genus:N. azelotes, previously only known from the type locality in Florida, andN. concinna, previously known from the Mediterranean. A third species,Narrimania raquelaesp. nov. is described from eastern Brazil, diagnosed by its numerous and thinner cancellate sculpture. To the three species ofOpaliopsispreviously known from Brazil, a fourth species,O. arnaldoisp. nov., is added from eastern Brazil, and diagnosed by its very thin spiral sculpture, absence of a varix, and thinner microscopic parallel axial striae.Papuliscala nordestina, originally described from north-east Brazil, is recorded off eastern Brazil and synonymized withP. elongata, a species previously known only from the North Atlantic.

scholarly journals Late antique necropolis in Davidovac-Crkviste

Starinar ◽  
2013 ◽  
pp. 269-286
Author(s):  
Perica Spehar ◽  
Natasa Miladinovic-Radmilovic ◽  
Sonja Stamenkovic
Keyword(s):  
Bronze Age ◽  
Late Antiquity ◽  
Late Antique ◽  
The South ◽  
The North ◽  
South West ◽  
North Eastern ◽  
Constantius Ii ◽  
Small Finds ◽  
Roman Province

In 2012, in the village Davidovac situated in south Serbia, 9.5 km south-west from Vranje, archaeological investigations were conducted on the site Crkviste. The remains of the smaller bronze-age settlement were discovered, above which a late antique horizon was later formed. Apart from modest remains of a bronze-age house and pits, a late antique necropolis was also excavated, of which two vaulted tombs and nine graves were inspected during this campaign. During the excavation of the northern sector of the site Davidovac-Crkviste the north-eastern periphery of the necropolis is detected. Graves 1-3, 5 and 6 are situated on the north?eastern borderline of necropolis, while the position of the tombs and the remaining four graves (4, 7-9) in their vicinity point that the necropolis was further spreading to the west and to the south?west, occupying the mount on which the church of St. George and modern graveyard are situated nowadays. All graves are oriented in the direction SW-NE, with the deviance between 3? and 17?, in four cases toward the south and in seven cases toward the north, while the largest part of those deviations is between 3? and 8?. Few small finds from the layer above the graves can in some way enable the determination of their dating. Those are two roman coins, one from the reign of emperor Valens (364-378), as well as the fibula of the type Viminacium-Novae which is chronologically tied to a longer period from the middle of the 5th to the middle of the 6th century, although there are some geographically close analogies dated to the end of the 4th or the beginning of the 5th century. Analogies for the tombs from Davidovac can be found on numerous sites, like in Sirmium as well as in Macvanska Mitrovica, where they are dated to the 4th-5th century. Similar situation was detected in Viminacium, former capital of the roman province of Upper Moesia. In ancient Naissus, on the site of Jagodin Mala, simple rectangular tombs were distributed in rows, while the complex painted tombs with Christian motifs were also found and dated by the coins to the period from the 4th to the 6th century. Also, in Kolovrat near Prijepolje simple vaulted tombs with walled dromos were excavated. During the excavations on the nearby site Davidovac-Gradiste, 39 graves of type Mala Kopasnica-Sase dated to the 2nd-3rd century were found, as well as 67 cist graves, which were dated by the coins of Constantius II, jewellery and buckles to the second half of the 4th or the first half of the 5th century. Based on all above mentioned it can be concluded that during the period from the 2nd to the 6th century in this area existed a roman and late antique settlement and several necropolises, formed along an important ancient road Via militaris, traced at the length of over 130 m in the direction NE-SW. Data gained with the anthropological analyses of 10 skeletons from the site Davidovac-Crkviste don't give enough information for a conclusion about the paleo-demographical structure of the population that lived here during late antiquity. Important results about the paleo-pathological changes, which do not occur often on archaeological sites, as well as the clearer picture about this population in total, will be acquired after the osteological material from the site Davidovac-Gradiste is statistically analysed.

Caledonian terrane amalgamation of Svalbard: detrital zircon provenance of Mesoproterozoic to Carboniferous strata from Oscar II Land, western Spitsbergen

2013 ◽  
Vol 150 (6) ◽  
pp. 1103-1126 ◽  
Author(s):  
DETA GASSER ◽  
ARILD ANDRESEN
Keyword(s):  
Detrital Zircon ◽  
Large Scale ◽  
Strike Slip ◽  
Western Coast ◽  
Zircon Age ◽  
The North ◽  
Tectonic History ◽  
Icp Ms ◽  
Depositional Age ◽  
Sveconorwegian Orogen

AbstractThe tectonic origin of pre-Devonian rocks of Svalbard has long been a matter of debate. In particular, the origin and assemblage of pre-Devonian rocks of western Spitsbergen, including a blueschist-eclogite complex in Oscar II Land, are enigmatic. We present detrital zircon U–Pb LA-ICP-MS data from six Mesoproterozoic to Carboniferous samples and one U–Pb TIMS zircon age from an orthogneiss from Oscar II Land in order to discuss tectonic models for this region. Variable proportions of Palaeo- to Neoproterozoic detritus dominate the metasedimentary samples. The orthogneiss has an intrusion age of 927 ± 3 Ma. Comparison with detrital zircon age spectra from other units of similar depositional age within the North Atlantic region indicates that Oscar II Land experienced the following tectonic history: (1) the latest Mesoproterozoic sequence was part of a successor basin which originated close to the Grenvillian–Sveconorwegian orogen, and which was intruded byc. 980–920 Ma plutons; (2) the Neoproterozoic sediments were deposited in a large-scale basin which stretched along the Baltoscandian margin; (3) the eclogite-blueschist complex and the overlying Ordovician–Silurian sediments probably formed to the north of the Grampian/Taconian arc; (4) strike-slip movements assembled the western coast of Spitsbergen outside of, and prior to, the main Scandian collision; and (5) the remaining parts of Svalbard were assembled by strike-slip movements during the Devonian. Our study confirms previous models of complex Caledonian terrane amalgamation with contrasting tectonic histories for the different pre-Devonian terranes of Svalbard and particularly highlights the non-Laurentian origin of Oscar II Land.

scholarly journals Paleoproterozoic Multiple Tectonothermal Events in the Longshoushan Area, Western North China Craton and Their Geological Implication: Evidence from Geochemistry, Zircon U–Pb Geochronology and Hf Isotopes

Minerals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 361 ◽  
Author(s):  
Renyu Zeng ◽  
Jianqing Lai ◽  
Xiancheng Mao ◽  
Bin Li ◽  
Jiandong Zhang ◽  
...  
Keyword(s):  
North China Craton ◽  
Tectonic Evolution ◽  
North China ◽  
Regional Metamorphism ◽  
Hf Isotope ◽  
Crustal Growth ◽  
Quartz Syenite ◽  
Isotope Data ◽  
The North ◽  
Rock Types

The Alxa block is located in the southwestern margin of the North China Craton. The Paleoproterozoic tectonic evolution, crustal growth and tectonic affinity of the block remain unknown or controversial. The Longshoushan (LS) area is one of the few areas that outcrop Paleoproterozoic to crystalline basement rocks in the Alxa Block. In this study, we preset whole-rock geochemistry, zircon U–Pb geochronology and Lu–Hf isotope data from metagabbro, metadiorite, quartz syenite, granitic leucosome and pegmatoid leucosome in the LS area. These rocks all are enriched in LREE and LILE, and depleted in HREE and HFSE. Eight new LA-ICP-MS zircon U–Pb ages yielded three magmatic ages of 2044 Ma, 2029 Ma and 1940 Ma, and three metamorphic ages of 1891 Ma, 1848 Ma and 1812 Ma. Lu–Hf analyses reveal that the magmatic zircons and anatectic/metamorphic zircons from all the rock types are characterized by positive εHf(t) (−0.16 to 10.89) and variable εHf(t) (−11.21 to 6.24), respectively. Based on the previous studies and our new data, we conclude that the LS area experienced three magmatic events (2.5–2.45 Ga, ~2.1–2.0 Ga and ~1.95–1.91 Ga) and three regional metamorphism/anataxis events (~1.93–1.89 Ga, ~1.86–1.84 Ga and ~1.81 Ga) in Paleoproterozoic. The age–Hf isotope data establishes two main crustal growth events at ~2.9–2.5 Ga and ~2.2–2.0 Ga in the LS area. These data indicate that the LS area experienced intraplate extensional setting in the middle Paleoproterozoic, and continental subduction, collision and exhumation in the late Paleoproterozoic. Combining the geochronological framework and tectonic evolution, we suggest that the Alxa Block is part of the Khondalite Belt.

scholarly journals II.—Topography: Bardoúnia and North-Eastern Maina

1910 ◽  
Vol 16 ◽  
pp. 62-71
Author(s):  
H. A. O.
Keyword(s):  
The South ◽  
Hill Country ◽  
The Road ◽  
Eastern Side ◽  
The North ◽  
North Eastern ◽  
The Hill

The following paper, which completes the series of papers on the classical topography of Laconia, is an account of the hill-country on the eastern side of Taÿgetos, bounded on the north by the road from Sparta to Anavryté, on the south by Gytheion and Pánitsa. (Fig.1.)

scholarly journals Seasonal variability and anomalies of the currents of the cyclonic gyre in the northeastern sector of Caspian sea

2019 ◽  
Vol 46 (5) ◽  
pp. 485-495
Author(s):  
A. K. Ambrosimov
Keyword(s):  
Experimental Data ◽  
Caspian Sea ◽  
Cold Water ◽  
Eastern Region ◽  
Cyclonic Gyre ◽  
Southern Slope ◽  
The South ◽  
Near Surface ◽  
The North ◽  
North Eastern

The experimental data presented in the article show that in the North-Eastern sector of the Middle Caspian sea in the area of Peschanomyssky uplift there is a disturbance of currents caused by the interaction of the cyclonic cycle with the southern slope of the uplift. As a result of this interaction, the waters of the cyclonic cycle are divided into branches – the lower and upper. The lower bottom branch is thrown by the uplift in the South-Western direction, where at the Cape of the uplift it collides with the waters flowing down the bottom of the South-Buzachinsky deflection in the South-Eastern direction, and the upper branch, consisting of near-surface and intermediate cold waters, is pushed up and passes through the uplift. As a result of the rise of cold water in the surface layer formed upwelling, which extends to the entire North-Eastern region of the sea.

scholarly journals Age and sources of the metasedimrntary rocks of the Tokur terrane in the Mongol-Okhotsk fold belt: results of the U–Pb geoсhronological and Lu–Hf isotope studies

2019 ◽  
Vol 486 (4) ◽  
pp. 446-450
Author(s):  
V. A. Zaika ◽  
A. A. Sorokin ◽  
A. P. Sorokin
Keyword(s):  
Detrital Zircons ◽  
Hf Isotope ◽  
Fold Belt ◽  
Metasedimentary Rocks ◽  
The North ◽  
Icp Ms ◽  
North Asia ◽  
Southeastern Margin ◽  
Isotope Studies ◽  
Metamorphic Complexes

This paper presents the results of U–Pb (LA–ICP–MS) and Lu–Hf ­isotope studies of detrital zircons from metasedimentary rocks of the Tokur Terrane. It has been shown that metasedimentary rocks of the Tokur and Ekimchan formations are characterized by similar age peaks of detrital zircons, which indicates a close (or same) age of these formations. The lower age of the sedimentation is determined by the age of the youngest zircons of 326–323 Ma. The upper age boundary is determined of 254–251 Ma, based on the intruded of the Late Permian granitoids. The main sources of zircons in the metasedimentary rocks of the Tokur Terrane are the igneous and metamorphic complexes of the southeast framing of the North Asia Craton. The Tokur Terrane can be considered as a fragment of the Paleozoic accretionary complex, the formation in front of the southeastern margin of the North Asia Craton.

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