Determination of Earth's paleointensity: past and future

Abstract:

The Earth’s intensity fluctuates at different time scales and can be further used to investigate Earth’s deep interior geodynamic processes because the Earth’s field is originated from the convection of the fluid outer core. Therefore, it is rather important to construct reliable long-term pattern of paleointensity data. So far, absolute and relative paleointensity methods are the most conventional approaches respectively using discrete volcanic rocks and semi-continuous sediments. Besides, relative paleointensity construction using the oceanic crust is also an important method. Three methods have both pros and cons. With the accumulation of paleointensity data, more questions are raised and this has challenged our understanding of the geodynamo processes. Therefore, we need to reconsider how to obtain the reliable paleointensity pattern. Here, we put forward two important research directions: 1) by taking advantages of the historical lavas with known paleointenisty, intensive reevaluation of the criteria of the Thellier-Thellier type data even with positive pTRM checks, which cannot guarantee the success of paleointensity results as evident by historic lava; 2) detailed comparison and construction of different paleointensoty data set since the past 10 Ma need to be conducted.