speed dating platforms - Magnetostratigraphic dating of loess deposits in china

The age control in the key layers indicates these anomalies are likely associated with the Laschamp and Blake excursions, respectively.

In addition, relative paleointensity in the loess section is basically compatible with other regional and global relative paleointensity records and indicates two low-paleointensity zones, possibly corresponding to the Blake and Laschamp excursions, respectively.

After air-drying, bulk samples were then cut into 8 cm Magnetic susceptibilities at low field of 200 A/m with both low (0.976 k Hz) and high (3.904 k Hz) frequencies were measured with an AGICO MFK1-FA Kappabridge.

Then, percentage frequency-dependent susceptibility ( × 100%.

Isothermal remanent magnetization (IRM) was gained in stepwise pulse fields using a MMPM9 pulse magnetizer and measured using a Molspin spinner magnetometer.

Hysteresis loops with relevant parameters were determined using an alternating gradient field magnetometer Micromag 2900 with a maximum field of 0.8 T.

Geomagnetic excursions during Brunhes epoch have been brought to the forefront topic in paleomagnetic study, as they provide key information about Earth’s interior dynamics and could serve as another tool for stratigraphic correlation among different lithology.

Loess–paleosol sequences provide good archives for decoding geomagnetic excursions.

In the northern piedmont of the Tianshan, the dusts mainly from the Saryesik-Atyrau Desert to the west and Gurbantunggut to the north formed huge loess/loessic belts with the assistance of prevailing winds (Li et al. The first layer (0–1.8 m) comprises the loessic loam and weakly paleosols, which was considered to be formed during the Holocene.

The loess horizon, ranging from 1.8 to 19.3 m, is characterized by uniform silt and relatively hard textures.

As a result, this study suggests that the loess section may have the potential to record short-lived excursions, which largely reflect the variation of dipole components in the global archives.).

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