Magnetism of Chinese loess deposits

Dados Bibliográficos

ID23379487
AutoresFriedrich Heller (0000-0002-0611-9614, ETH Zurich), L Tungsheng (Institute of Geology and Geophysics)
Ano1984
Volume77
Fascículo1
Páginas125-141
Data de publicação1984-04-01
Peer ReviewedSim
Open AccessSim
TipoARTICLE
PeriódicoGeophysical Journal International (JOURNAL)
Identificadores do periódicoISSN: 0956-540X • E-ISSN: 1365-246X
EditoraOxford University Press (OUP) (PUBLISHER)
DOI10.1111/j.1365-246x.1984.tb01928.x
OpenAlexW2115265289
IdiomaEN
Citações recebidas76
Referências citadas27

The age of Chinese loess deposits has long been disputed. Biostratigraphical and earlier magnetostratigraphical investigations placed the entire loess formation within the Pleistocene and ascertained a maximum loess age of about 1.2 Myr. A new collection of nearly 500 samples from a natural outcrop and a borehole section near Lochuan (lat. 35.8°N, long. 109.2°E; Shaanxi province) has been dated by magnetic stratigraphy. Thermal cleaning of the natural remanent magnetization (NRM) removes a strong secondary component of viscous origin along the present geomagnetic field which resides largely in magnetite. The characteristic NRM component is due to haematite which is thought to be of chemical origin. Rhythmical intensity variations of NRM and initial susceptibility depend on the loess lithology and may reflect climatic changes during loess deposition. The palaeomagnetic results are consistent between the two sections and yield a clearly defined magnetic polarity zonation. The Brunhes-Matuyama boundary and the Jaramillo subchron have been positively identified in both outcrops at exactly the same stratigraphic level. The Olduvai subchron has been found in the borehole section which records the entire loess sequence. Most probably the formation of Chinese loess began shortly after the Matuyama-Gauss polarity transition. Therefore a late Pliocene age of about 2.4 Myr is assigned to the oldest loess sediments measured.

Chronostratigraphy · Lithology · Loess · Magnetization · Magnetostratigraphy · Natural remanent magnetization · Outcrop · Paleomagnetism · Pleistocene · Remanence · Sedimentary rock · Geological formations and processes · Geology · Geology and Paleoclimatology Research · Geomagnetism and Paleomagnetism Studies · Paleontology · Stratigraphy