期刊
PRECAMBRIAN RESEARCH
卷 323, 期 -, 页码 1-5出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/j.precamres.2019.01.009
关键词
Supercontinent; Superocean; Geodynamic; Subduction girdle; Introversion; Extroversion; Earth's supercycle
资金
- Australian Research Council Laureate Fellowship [FL150100133]
- Russian Mega-Grant [14.Y26.31.0012]
The supercontinent cycle of episodic assembly and breakup of almost all continents on Earth is commonly considered the longest period variation to affect mantle convection. However, global zircon Hf isotopic signatures and seawater Sr isotope ratios suggest the existence of a longer-term variation trend that is twice the duration of the supercontinent cycle. Here we propose that since similar to 2 billion years ago the superocean surrounding a supercontinent, as well as the circum-supercontinent subduction girdle, survive every second supercontinent cycle. This interpretation is in agreement with global palaeogeography and is supported by variations in passive margin, orogen, and mineral deposit records that each exhibits both similar to 500-700 million years periodic signal and a 1000-1500 million years variation trend. We suggest that the supercontinent cycle is modulated by an assembly that alternates between dominantly extroversion after a more complete breakup, and dominantly introversion after an incomplete breakup of the previous supercontinent.
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