scholarly journals The lead-up to the Sturtian Snowball Earth: Neoproterozoic chemostratigraphy time-calibrated by the Tambien Group of Ethiopia

2019 ◽  
Vol 132 (5-6) ◽  
pp. 1119-1149 ◽  
Author(s):  
Yuem Park ◽  
Nicholas L. Swanson-Hysell ◽  
Scott A. MacLennan ◽  
Adam C. Maloof ◽  
Mulubrhan Gebreslassie ◽  
...  
Keyword(s):  
Large Igneous Province ◽  
Snowball Earth ◽  
Ionization Mass ◽  
Data Sets ◽  
Northern Ethiopia ◽  
Glacial Deposits ◽  
Igneous Province ◽  
Low Latitudes ◽  
Back Arc ◽  
The Tropics

Abstract The Tonian-Cryogenian Tambien Group of northern Ethiopia is a mixed carbonate-siliciclastic sequence that culminates in glacial deposits associated with the first of the Cryogenian glaciations—the Sturtian “Snowball Earth.” Tambien Group deposition occurred atop arc volcanics and volcaniclastics of the Tsaliet Group. New U-Pb isotope dilution–thermal ionization mass spectrometry (ID-TIMS) dates demonstrate that the transition between the Tsaliet and Tambien Groups occurred at ca. 820 Ma in western exposures and ca. 795 Ma in eastern exposures, which is consistent with west to east arc migration and deposition in an evolving back-arc basin. The presence of intercalated tuffs suitable for high-precision geochronology within the Tambien Group enable temporal constraints on stratigraphic data sets of the interval preceding, and leading into, the Sturtian glaciation. Recently discovered exposures of Sturtian glacial deposits and underlying Tambien Group strata in the Samre Fold-Thrust Belt present the opportunity to further utilize this unique association of tuffs and carbonate lithofacies. U-Pb ID-TIMS ages from zircons indicate that Tambien Group carbonates were deposited from ca. 820 Ma until 0–2 m.y. before the onset of the Sturtian glaciation, making the group host to a relatively complete carbonate stratigraphy leading into this glaciation. New δ13C and 87Sr/86Sr data and U-Pb ID-TIMS ages from the Tambien Group are used in conjunction with previously published isotopic and geochronologic data to construct newly time-calibrated composite Tonian carbon and strontium isotope curves. Tambien Group δ13C data and U-Pb ID-TIMS ages reveal that a pre-Sturtian sharp negative δ13C excursion (referred to as the Islay anomaly in the literature) precedes the Sturtian glaciation by ∼18 m.y., is synchronous in at least two separate basins, and is followed by a prolonged interval of positive δ13C values. The composite Tonian 87Sr/86Sr curve shows that, following an extended interval of low and relatively invariant values, inferred seawater 87Sr/86Sr rose ca. 880–770 Ma, then subsequently decreased leading up to the ca. 717 Ma initiation of the Sturtian glaciation. These data, when combined with a simple global weathering model and analyses of the timing and paleolatitude of large igneous province eruptions and arc accretion events, suggest that the 87Sr/86Sr increase was influenced by increased subaerial weathering of radiogenic lithologies as Rodinia rifted apart at low latitudes. The following 87Sr/86Sr decrease is consistent with enhanced subaerial weathering of arc lithologies accreting in the tropics over tens of millions of years, lowering pCO2 and contributing to the initiation of the Sturtian glaciation.

scholarly journals Late Paleoproterozoic mafic magmatism and the Kalahari craton during Columbia assembly

Geology ◽  
2021 ◽  
Author(s):  
Cedric Djeutchou ◽  
Michiel O. de Kock ◽  
Hervé Wabo ◽  
Camilo E. Gaitán ◽  
Ulf Söderlund ◽  
...  
Keyword(s):  
Thermal Ionization Mass Spectrometry ◽  
Black Hills ◽  
Large Igneous Province ◽  
Ionization Mass ◽  
Data Sets ◽  
Geochronological Data ◽  
Pb Isotope ◽  
Kalahari Craton ◽  
Igneous Province ◽  
Superior Craton

The 1.87–1.84 Ga Black Hills dike swarm of the Kalahari craton (South Africa) is coeval with several regional magmatic provinces used here to resolve the craton’s position during Columbia assembly. We report a new 1850 ± 4 Ma (U-Pb isotope dilution–thermal ionization mass spectrometry [ID-TIMS] on baddeleyite) crystallization age for one dike and new paleomagnetic data for 34 dikes of which 8 have precise U-Pb ages. Results are constrained by positive baked-contact and reversal tests, which combined with existing data produce a 1.87–1.84 Ga mean pole from 63 individual dikes. By integrating paleomagnetic and geochronological data sets, we calculate poles for three magmatic episodes and produce a magnetostratigraphic record. At 1.88 Ga, the Kalahari craton is reconstructed next to the Superior craton so that their ca. 2.0 Ga poles align. As such, magmatism forms part of a radiating pattern with the coeval ca. 1.88 Ga Circum-Superior large igneous province.

U–Pb geochronology of Cretaceous magmatism on Svalbard and Franz Josef Land, Barents Sea Large Igneous Province

2013 ◽  
Vol 150 (6) ◽  
pp. 1127-1135 ◽  
Author(s):  
FERNANDO CORFU ◽  
STÉPHANE POLTEAU ◽  
SVERRE PLANKE ◽  
JAN INGE FALEIDE ◽  
HENRIK SVENSEN ◽  
...  
Keyword(s):  
Thermal Ionization Mass Spectrometry ◽  
Barents Sea ◽  
Large Igneous Province ◽  
The Arctic ◽  
Ionization Mass ◽  
Franz Josef Land ◽  
Igneous Province ◽  
Stratigraphic Record ◽  
Single Grain ◽  
Cretaceous Magmatism

AbstractThe opening of the Arctic oceanic basins in the Mesozoic and Cenozoic proceeded in steps, with episodes of magmatism and sedimentation marking specific stages in this development. In addition to the stratigraphic record provided by sediments and fossils, the intrusive and extrusive rocks yield important information on this evolution. This study has determined the ages of mafic sills and a felsic tuff in Svalbard and Franz Josef Land using the isotope dilution thermal ionization mass spectrometry (ID-TIMS) U–Pb method on zircon, baddeleyite, titanite and rutile. The results indicate crystallization of the Diabasodden sill at 124.5 ± 0.2 Ma and the Linnévatn sill at 124.7 ± 0.3 Ma, the latter also containing slightly younger secondary titanite with an age of 123.9 ± 0.3 Ma. A bentonite in the Helvetiafjellet Formation, also on Svalbard, has an age of 123.3 ± 0.2 Ma. Zircon in mafic sills intersected by drill cores in Franz Josef Land indicate an age of 122.7 Ma for a thick sill on Severnaya Island and a single grain age of ≥122.2 ± 1.1 Ma for a thinner sill on Nagurskaya Island. These data emphasize the importance and relatively short-lived nature of the Cretaceous magmatic event in the region.

scholarly journals Timing and tempo of the Great Oxidation Event

2017 ◽  
Vol 114 (8) ◽  
pp. 1811-1816 ◽  
Author(s):  
Ashley P. Gumsley ◽  
Kevin R. Chamberlain ◽  
Wouter Bleeker ◽  
Ulf Söderlund ◽  
Michiel O. de Kock ◽  
...  
Keyword(s):  
Atmospheric Oxygen ◽  
Kaapvaal Craton ◽  
Large Igneous Province ◽  
Snowball Earth ◽  
Low Latitude ◽  
Great Oxidation Event ◽  
Carbon Isotope Excursion ◽  
Igneous Province ◽  
Age Constraints ◽  
Exact Timing

The first significant buildup in atmospheric oxygen, the Great Oxidation Event (GOE), began in the early Paleoproterozoic in association with global glaciations and continued until the end of the Lomagundi carbon isotope excursion ca. 2,060 Ma. The exact timing of and relationships among these events are debated because of poor age constraints and contradictory stratigraphic correlations. Here, we show that the first Paleoproterozoic global glaciation and the onset of the GOE occurred between ca. 2,460 and 2,426 Ma, ∼100 My earlier than previously estimated, based on an age of 2,426 ± 3 Ma for Ongeluk Formation magmatism from the Kaapvaal Craton of southern Africa. This age helps define a key paleomagnetic pole that positions the Kaapvaal Craton at equatorial latitudes of 11° ± 6° at this time. Furthermore, the rise of atmospheric oxygen was not monotonic, but was instead characterized by oscillations, which together with climatic instabilities may have continued over the next ∼200 My until ≤2,250–2,240 Ma. Ongeluk Formation volcanism at ca. 2,426 Ma was part of a large igneous province (LIP) and represents a waning stage in the emplacement of several temporally discrete LIPs across a large low-latitude continental landmass. These LIPs played critical, albeit complex, roles in the rise of oxygen and in both initiating and terminating global glaciations. This series of events invites comparison with the Neoproterozoic oxygen increase and Sturtian Snowball Earth glaciation, which accompanied emplacement of LIPs across supercontinent Rodinia, also positioned at low latitude.

Magmatic duration of the Emeishan large igneous province: Insight from northern Vietnam

Geology ◽  
2020 ◽  
Vol 48 (5) ◽  
pp. 457-461 ◽  
Author(s):  
J. Gregory Shellnutt ◽  
Thuy Thanh Pham ◽  
Steven W. Denyszyn ◽  
Meng-Wan Yeh ◽  
Tuan-Anh Tran
Keyword(s):  
High Precision ◽  
Thermal Ionization Mass Spectrometry ◽  
Volcanic Rocks ◽  
Large Igneous Province ◽  
Ionization Mass ◽  
Emeishan Large Igneous Province ◽  
Northern Vietnam ◽  
Global Cooling ◽  
Igneous Province ◽  
Distinct Period

Abstract The eruption of Emeishan lava in southwestern China and northern Vietnam is considered to be a contributing factor to the Capitanian mass extinction and subsequent global cooling event, but the duration of volcanism is uncertain. The difficulty in assessing the termination age is, in part, due to the lack of high-precision age data for late-stage volcanic rocks. The Tu Le rhyolite of northern Vietnam is the most voluminous silicic unit of the Emeishan large igneous province (ELIP) and is spatially associated with the Muong Hum and Phan Si Pan hypabyssal plutons. Chemical abrasion–isotope dilution–thermal ionization mass spectrometry U-Pb dating of zircons from the Tu Le rhyolite (257.1 ± 0.6 Ma to 257.9 ± 0.3 Ma) and Muong Hum (257.3 ± 0.2 Ma) and Phan Si Pan (256.3 ± 0.4 Ma) plutons yielded the youngest high-precision ages of the ELIP yet determined. The results demonstrate that Emeishan lavas erupted over a period of ∼6 m.y,. with plutonism ending shortly thereafter. Thus, it is possible that Emeishan volcanism contributed to global cooling into the middle Wuchiapingian. It appears that these rocks represent a distinct period of ELIP magmatism, as they are young and were emplaced oblique to the main north-south–trending Panxi rift.

Low-Ti gabbroic pluton in Dali, SW China: new evidence for back-arc lithospheric melting inducing the early-stage magmatism of the Emeishan large igneous province

2021 ◽  
pp. jgs2020-224
Author(s):  
Bei Zhu ◽  
Zhaojie Guo ◽  
Shaonan Zhang ◽  
Ning Ye ◽  
Ziye Lu ◽  
...  
Keyword(s):  
Early Stage ◽  
Large Igneous Province ◽  
Spinel Peridotite ◽  
Heavy Rare Earth Element ◽  
Content Type ◽  
Igneous Province ◽  
Supplementary Material ◽  
Back Arc ◽  
Emeishan Lip ◽  
Yangtze Plate

The latest studies proved contribution of the Emeishan mantle plume (the widely-regarded origin of the Emeishan LIP in the western Yangtze Plate. LIP: large igneous province) to the Palaeo-Tethys subduction. However, whether the Palaeo-Tethys subduction oppositely affected the formation of the Emeishan LIP remains poorly understood. Here, we report geochronological, petrological, geochemical and isotopic studies of a gabbroic intrusion in this LIP, located in Jiangwei, the Dali area. The gabbro has a weighted mean SHRIMP U-Pb age of ∼262 Ma. Key geochemical features include Nb, Ta and Ti depletion; Th, U and Sr enrichment, low light/heavy rare earth element ratios and ∼0.707 87Sr/86Sr(t) and ∼-0.21 εNd(t) values. We conducted pMELTS thermodynamic modeling and batch melting calculations to evaluate the origin and evolution of the gabbro, based on real components of low-Ti picrites and xenolith of the Yangtze lithosphere. The results support 3% melting of a hydrated spinel peridotite source from the Yangtze lithosphere can produce magma equivalent to the gabbro components. Integrating this conclusion with tectonic background of the western Yangtze Plate and volcano-stratigraphic record of the Emeishan LIP, we infer the early-stage magmatism of the Emeishan LIP was triggered by Paleo-Tethys back-arc extension with fluid modification from subductional slab.Supplementary material:https://doi.org/10.6084/m9.figshare.c.5433267

Constraining the duration of the Tarim flood basalts (northwestern China): CA-TIMS zircon U-Pb dating of tuffs

2021 ◽  
Author(s):  
Yu-Ting Zhong ◽  
Zhen-Yu Luo ◽  
Roland Mundil ◽  
Xun Wei ◽  
Hai-Quan Liu ◽  
...  
Keyword(s):  
Thermal Ionization Mass Spectrometry ◽  
Northwest China ◽  
Lava Flows ◽  
Northwestern China ◽  
Large Igneous Province ◽  
Ionization Mass ◽  
Flood Basalts ◽  
Eruption Rate ◽  
Long Duration ◽  
Igneous Province

The Early Permian Tarim large igneous province (LIP) in northwestern China comprises voluminous basaltic lava flows, as well as ultramafic and silicic intrusions. The age and duration of the Tarim LIP remains unclear, and thus the rate of magma production and models of potential environmental effects are uncertain. Here we present high-precision chemical abrasion−isotope dilution−thermal ionization mass spectrometry zircon U-Pb ages for three newly discovered tuff layers interlayered with lava flows in the Kupukuziman and Kaipaizileike formations in the Keping area (Xinjiang, northwest China). The volcanism of the Kupukuziman Formation is constrained to a short duration from 289.77 ± 0.95 to 289.41 ± 0.52 Ma. An age for the overlying Kaipaizileike Formation is 284.27 ± 0.39 Ma, bracketing the duration of the entire eruptive phase of the Tarim flood basalts at ∼5.5 m.y. The low eruption rate and relatively long duration of magmatism is consistent with a plume incubation model for the Tarim LIP.

What triggered the early-stage eruption of the Emeishan large igneous province?

2019 ◽  
Vol 131 (11-12) ◽  
pp. 1837-1856 ◽  
Author(s):  
Bei Zhu ◽  
Zhaojie Guo ◽  
Shaonan Zhang ◽  
Ingrid Ukstins ◽  
Wei Du ◽  
...  
Keyword(s):  
Mantle Plume ◽  
Plate Tectonics ◽  
Early Stage ◽  
Volcanic Rocks ◽  
Large Igneous Province ◽  
Background Information ◽  
Gradual Transition ◽  
Emeishan Large Igneous Province ◽  
Igneous Province ◽  
Back Arc

Abstract The formation of the Emeishan large igneous province is widely regarded as being related to a mantle plume, but plate tectonics may also have played an important role. We analyzed the regional facies architecture of the early-stage subaqueous volcanic rocks of the central Emeishan large igneous province. The results suggest that these rocks were emplaced in a N-S–striking subaqueous rift, which existed immediately before the onset of volcanism and was persistently maintained during the early eruption stage. By linking this conclusion with the background information indicating that (1) the basaltic geochemistry in this section is indicative of a subcontinental lithospheric mantle source rather than a mantle plume source, and (2) the western Yangtze plate, where the Emeishan large igneous province was developed, was located in the back-arc region of the Permian Paleo-Tethys subduction system, we propose a new view that the early-stage eruptions of the Emeishan large igneous province were triggered by back-arc extension. The dominant functioning of the mantle plume occurred shortly after this process and inherited it, as evidenced by the following: (1) The subaqueous volcanic architecture showing back-arc geochemical affinity is laterally restricted in the presumed rift, but the overlying subaerial lavas showing plume-related geochemical features overwhelmingly flooded the whole province; (2) vertically, the source of the basaltic component in these intrarift sequences underwent a gradual transition from lithospheric origin to mantle plume origin along the stratigraphic order, as evidenced by an intercalated basaltic succession showing mixed geochemical features from the two contextual origins.

scholarly journals Subduction history of the Caribbean from upper-mantle seismic imaging and plate reconstruction

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Benedikt Braszus ◽  
Saskia Goes ◽  
Rob Allen ◽  
Andreas Rietbrock ◽  
Jenny Collier ◽  
...  
Keyword(s):  
Upper Mantle ◽  
Large Igneous Province ◽  
Fracture Zones ◽  
Igneous Province ◽  
Wave Imaging ◽  
History Of ◽  
The Caribbean ◽  
Subducting Plate ◽  
Plate Reconstruction ◽  
Back Arc

AbstractThe margins of the Caribbean and associated hazards and resources have been shaped by a poorly understood history of subduction. Using new data, we improve teleseismic P-wave imaging of the eastern Caribbean upper mantle and compare identified subducted-plate fragments with trench locations predicted from plate reconstruction. This shows that material at 700–1200 km depth below South America derives from 90–115 Myr old westward subduction, initiated prior to Caribbean Large-Igneous-Province volcanism. At shallower depths, an accumulation of subducted material is attributed to Great Arc of the Caribbean subduction as it evolved over the past 70 Ma. We interpret gaps in these subducted-plate anomalies as: a plate window and tear along the subducted Proto-Caribbean ridge; tearing along subducted fracture zones, and subduction of a volatile-rich boundary between Proto-Caribbean and Atlantic domains. Phases of back-arc spreading and arc jumps correlate with changes in age, and hence buoyancy, of the subducting plate.

A link between rift-related volcanism and end-Ediacaran extinction? Integrated chemostratigraphy, biostratigraphy, and U-Pb geochronology from Sonora, Mexico

Geology ◽  
2020 ◽  
Author(s):  
Eben B. Hodgin ◽  
Lyle L. Nelson ◽  
Corey J. Wall ◽  
Arturo J. Barrón-Díaz ◽  
Lucy C. Webb ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Thermal Ionization Mass Spectrometry ◽  
Flood Basalt ◽  
Large Igneous Province ◽  
Ionization Mass ◽  
Carbon Isotope Excursion ◽  
Igneous Province ◽  
First Occurrence ◽  
Thermal Ionization Mass ◽  
Depositional Age

We present chemostratigraphy, biostratigraphy, and geochronology from a succession that spans the Ediacaran-Cambrian boundary in Sonora, Mexico. A sandy hematite-rich dolostone bed, which occurs 20 m above carbonates that record the nadir of the basal Cambrian carbon isotope excursion within the La Ciénega Formation, yielded a maximum depositional age of 539.40 ± 0.23 Ma using U-Pb chemical abrasion–isotope dilution–thermal ionization mass spectrometry on a population of sharply faceted volcanic zircon crystals. This bed, interpreted to contain reworked tuffaceous material, is above the last occurrences of late Ediacaran body fossils and below the first occurrence of the Cambrian trace fossil Treptichnus pedum, and so the age calibrates key markers of the Ediacaran-Cambrian boundary. The temporal coincidence of rift-related flood basalt volcanism in southern Laurentia (>250,000 km3 of basalt), a negative carbon isotope excursion, and biological turnover is consistent with a mechanistic link between the eruption of a large igneous province and end-Ediacaran extinction.

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