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The first detailed chronology for the late Oligocene to early Miocene continental record in northern Junggar Basin is presented,based on rock magnetic experiments and magnetostratigraphic investiga-tions of a 192 m thick mammal-bearing section in the Ulungur River area. Magnetites and hematites were identified as the main carriers for the characteristic remanent magnetization,and the resulting polarity sequence allows an unambiguous correlation to the geomagnetic polarity time scale (GPTS). Furthermore,the Tieersihabahe fauna layer occurs below the Paleocene/Neocene boundary,and the Suosuoquan fauna layer is just above the Neocene onset. Therefore,the age of the Tieersihabahe fauna and Suosuoquan fauna layers can be definitely estimated to be about 25.2 Ma and 22.5 Ma,respectively.
The first detailed chronology for the late Oligocene to early Miocene continental record in northern Junggar Basin is presented, based on rock magnetic experiments and magnetostratigraphic investiga- tions of a 192 m thick mammal-bearing section in the Ulungur River area. Magnetites and hematites were identified as the main carriers for the characteristic remanent magnetization, and the resulting polarity sequence allows an unambiguous correlation to geomagnetic polarity time scale (GPTS). Furthermore, the Tieersihabahe fauna layer occurs below the the Paleocene / Neocene boundary, and the Suosuoquan fauna layer is just above the Neocene onset. Thus, the age of the Tieersihabahe fauna and Suosuoquan fauna layers can be definitely estimated to be about 25.2 Ma and 22.5 Ma, respectively.