scholarly journals The 1.24–1.21 Ga Licheng Large Igneous Province in the North China Craton: Implications for Paleogeographic Reconstruction

2020 ◽  
Vol 125 (4) ◽  
Author(s):  
Chong Wang ◽  
Peng Peng ◽  
Zheng‐Xiang Li ◽  
Sergei Pisarevsky ◽  
Steven Denyszyn ◽  
...  
Keyword(s):  
North China Craton ◽  
North China ◽  
Large Igneous Province ◽  
Paleogeographic Reconstruction ◽  
The North ◽  
Igneous Province

A 1.78 Ga large igneous province in the North China craton: The Xiong'er Volcanic Province and the North China dyke swarm

Lithos ◽  
2008 ◽  
Vol 101 (3-4) ◽  
pp. 260-280 ◽  
Author(s):  
Peng Peng ◽  
Mingguo Zhai ◽  
Richard E. Ernst ◽  
Jinghui Guo ◽  
Fu Liu ◽  
...  
Keyword(s):  
North China Craton ◽  
North China ◽  
Large Igneous Province ◽  
Dyke Swarm ◽  
Volcanic Province ◽  
The North ◽  
Igneous Province

scholarly journals Reconstructing Tonian seawater 87Sr/86Sr using calcite microspar

Geology ◽  
2020 ◽  
Vol 48 (5) ◽  
pp. 462-467 ◽  
Author(s):  
Ying Zhou ◽  
Philip A.E. Pogge von Strandmann ◽  
Maoyan Zhu ◽  
Hongfei Ling ◽  
Christina Manning ◽  
...  
Keyword(s):  
North China Craton ◽  
North China ◽  
Phosphorus Content ◽  
Large Igneous Province ◽  
Flood Basalts ◽  
The North ◽  
Carbon Burial ◽  
Igneous Province ◽  
Radiometric Ages ◽  
Age Constraints

Abstract The Tonian Period followed a long interval of relative stasis and led into the climatic extremes and biological radiations of multicellular life during the Cryogenian and Ediacaran Periods, respectively. However, despite its pivotal situation, it remains relatively understudied, in large part due to the lack of robust age constraints. A combination of fossil evidence, radiometric ages, and isotopic constraints reveal that carbonate strata on the North China craton were deposited between ca. 980 and ca. 920 Ma, thereby filling a gap in marine archives. Here we present 87Sr/86Sr data from selected calcite microspar cements, which filled early diagenetic “molar tooth” cracks, along with data from demonstrably well-preserved bulk carbonate samples. These new data show that seawater 87Sr/87Sr rose in stages from ∼0.7052 at ca. 980 Ma to ∼0.7063 by ca. 920 Ma, after which a return to low values coincided with the eruption of the Dashigou large igneous province across the North China craton. We also present a new Neoproterozoic seawater 87Sr/86Sr curve, which reveals that the general trend toward higher 87Sr/87Sr during the Tonian Period was checked repeatedly by the input of less-radiogenic strontium from a series of eruptive events, both coincident with and prior to the main breakup of Rodinia. The weathering of Tonian volcanic provinces has been linked to higher carbon burial, glaciation, and oxygenation due to the high phosphorus content of flood basalts. Here we show that the weathering of major volcanic provinces affected material fluxes and ocean chemistry much earlier than previously envisaged.

Magnetic fabric and rock magnetic studies of the ~1.78 Ga large igneous province in the North China Craton and its implication for the configuration of the supercontinent Nuna/Columbia

2020 ◽  
Author(s):  
Huiru Xu ◽  
Tao Yang ◽  
Mark Dekkers ◽  
Peng Peng ◽  
Kunpeng Ge ◽  
...  
Keyword(s):  
North China Craton ◽  
North China ◽  
Tectonic Setting ◽  
Large Igneous Province ◽  
Magma Source ◽  
The South ◽  
Magma Flow ◽  
Eruption Center ◽  
Columbia Supercontinent ◽  
Igneous Province

<p>The paleo-position of the North China Craton (NCC) within the Supercontinent Nuna/Columbia is controversial. Hindered by ubiquitous alteration of the very ancient rocks, paleomagnetic studies have not been able yet to conclusively solve this puzzle. Comprehensive analysis on the relatively limited Precambrian records is essential to understand the geological history of these cratons. Within the NCC, the tectonic setting of a ~1.78 Ga large igneous province (LIP) is long debated. It is considered to be related to a paleoplume, post-collision extension, or an Andean continental margin. Knowing its mode of formation constrains the geological evolution of the NCC and its paleo-position within the Supercontinent Nuna/Columbia. Here we conduct a study into the anisotropy of magnetic susceptibility (AMS) in the dykes and lavas of the ~1.78 Ga LIP, together with systematic rock magnetic experiments, to constrain the geological background of the igneous event(s), to understand the tectonic evolution of the NCC, as well as its paleo-position within the assembly of the Nuna/Columbia supercontinent.</p><p>Thirty-three dykes in the northern and middle parts and thirty lavas in the southern part of the NCC were collected. Detailed rock magnetic analyses indicate PSD magnetite to be the dominant magnetic mineral in the samples, occasionally with pyrrhotite in the dykes and hematite in the lavas. The often observed relatively weak anisotropy degree suggests that the AMS ellipsoids probably portray magma flow-related fabrics. The inferred directions from the AMS fabrics of the lavas reveal a radial flow pattern with an eruption center located on the south margin of the NCC. The studied dykes show a predominance of horizontally to subhorizontally northward magma flow, with only few vertical intrusions. These observations imply that the ~1.78 Ga LIP may have formed by magma source(s) at the south margin of the NCC. Some localized magma sub-chambers may have formed during the propagation of the magma and could have been responsible for the less common vertically intruded dykes and the EW-trending dykes. Therefore, we favor a plume-related tectonic setting for the ~1.78 Ga LIP with the eruption center along the margin of the NCC. It can serve as an essential criterion to search for possible neighbour(s) of the NCC within Nuna/Columbia, which should preserve the relics of the ~1.78 Ga LIP. Our study, in combination with extant geological and paleomagnetic results suggests a close linkage of the NCC with the São Francisco-Congo, Rio de la Plata and Siberia cratons in the Nuna/Columbia supercontinent.</p>

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