Evidence for weak geomagnetic field intensity prior to the Cretaceous normal superchron

Details Evidence for weak geomagnetic field intensity prior to the Cretaceous normal superchron Evidence for weak geomagnetic field intensity prior to the Cretaceous normal superchron

Apr 2003

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003pepi..136..187z&link_type=abstract

Physics of the Earth and Planetary Interiors, Volume 136, Issue 3-4, p. 187-199.

Physics

10

Scientific paper

A palaeomagnetic and geochronologic investigation has been carried out on a sequence of 19 lava flows at Sihetun in northeastern China. Age determinations by K/Ar dating indicate that the sequence spans 124-133Ma, that is, the time just prior to Cretaceous normal superchron (CNS). Rock magnetic measurements of thermomagnetic curves and hysteresis loops show the primary carrier of remanence to be pseudo-single domain magnetite. Stepwise thermal demagnetization successfully isolated a well-defined direction of characteristic magnetization (ChRM) in all the lavas. The mean palaeodirection determined is D//I=5.4°/58.7° (α95=2.4°) and D//I=175.9°/-60.0° (α95=6.4°) for 15 normally magnetized flows and 3 reversely magnetized flows, respectively. One lava was found to possess an intermediate direction of magnetization. The inferred palaeolatitude of the sampling site is very similar to the present-day position, supporting the contention that suturing between the Mongolia and north China plates was probably completed by the Late Jurassic, and that subsequently little rotation or translation occurred in the region west of the Tanlu fault zone. Thellier-Thellier palaeointensity experiments with systematic partial thermoremanent magnetization (pTRM) checks were conducted on 66 samples from 13 lava flows. Results from the 29 samples (44%) which met strict reliability criteria indicate a range of virtual dipole moments (VDMs) from 2.83 to 4.17×1022Am2 with an average of (3.53+/-0.02)×1022Am2. This finding helps confirm that a weak geomagnetic field probably occurred just prior to the CNS.

Affiliated with

Also associated with

No associations

Rating

Evidence for weak geomagnetic field intensity prior to the Cretaceous normal superchron does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Evidence for weak geomagnetic field intensity prior to the Cretaceous normal superchron, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Evidence for weak geomagnetic field intensity prior to the Cretaceous normal superchron will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1325605