 |
| Detailed Reference Information |
|---|
|
Yoshihara, A. and Hamano, Y. (2000). Intensity of the Earth's magnetic field in late Archean obtained from diabase dikes of the Slave Province, Canada. Physics of the Earth and Planetary Interiors 117: 295-307. doi: 10.1016/S0031-9201(99)00103-X. |
|
|
The geomagnetic field intensity in Late Archean times is evaluated from Archean diabase dikes intruded into the Yellowknife greenstone belt of the Slave Province, N.W.T., Canada. The dike set used is referred to as the 8a dikes, and their age is bracketed between 2620 and 2642 Ma by crosscutting relationships between the 8a dikes and adjacent granitic rocks dated by U-Pb method. Paleomagnetic directional data after thermal demagnetization (ThD) and results of some field tests suggest that the characteristic remanent magnetizations (ChRM) of the dikes have been acquired at ca. 2.6 Ga. Several rock magnetic studies indicate that the dike samples are suitable for paleointensity determinations. Thelliers' method with consistency checks was used for the paleointensity determinations, and two of the 8a dikes yielded the mean paleointensities of 30.9+ or -1.1 and 43.9+ or -1.2 mu T, respectively. The corresponding virtual dipole moments (VDM) of (6.3+ or -0.2)X10 (super 22) A m (super 2) and (9.0+ or -0.2)X10 (super 22) A m (super 2) are similar to the present day value, suggesting that, in the Earth's core, the dynamo process of comparable activity to that of the present day has already existed at ca. 2.6 Ga. |
|
| DATABASE QUICK LINKS |
|
 |
MagIC Database |
 |
|
|
|
|
| BACKGROUND DATA FILES |
|
|
MagIC SmartBook v1 |
|
 |
|
|
|
Keywords
absolute age, Archean, Canada, Canadian Shield, characteristic, remanent magnetization, core, dates, demagnetization, diabase, dikes, greenstone belts, igneous rocks, inner core, intrusions, magnetic, field, magnetization, metamorphic belts, North America, paleomagnetism, plutonic rocks, Precambrian, remanent magnetization, Slave Province, thermal demagnetization, U/Pb, upper Archean, Yellowknife Belt, 18, Solid-earth geophysics |
|
Publisher
Elsevier Science
P.O. Box 211
1000 AE Amsterdam
The Netherlands
(+31) 20 485 3757
(+31) 20 485 3432
nlinfo-f@elsevier.com |
|
|
|