Mathematics – Logic
Scientific paper
Dec 1979
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1979e%26psl..46..125p&link_type=abstract
Earth and Planetary Science Letters, Volume 46, Issue 1, p. 125-137.
Mathematics
Logic
2
Scientific paper
Three closely spaced 6-m piston cores were taken in the central part of Lake Tahoe. Cores were split into two complete replicates for paleomagnetic study and the remaining sections were used for stratigraphic and mineralogical analysis. Stratigraphic correlation of the cores is based on two distinctive horizons (volcanic ash and diatomite) and upon three different sedimentological regimes dominated by (1) poorly bedded silts and muds, (2) well bedded graded units, and (3) finely laminated silts. These correlations served as the standards for the evaluation of the paleomagnetic data. Extrapolation of 14C dates obtained in the upper sections of the Lake Tahoe sediments suggests that the lower sections of the cores may reach ages of 25,000-30,000 years B.P. X-ray, optical, Curie point, and hysteresis measurements show that magnetite is the only important magnetic mineral in the sediments and occurs in the size range of 10 μm. Hematite is essentially absent. Based on large changes in the declination and inclination of the natural remanent magnetism (NRM) within single graded layers the paleomagnetic signature is a post-depositional remanent magnetism (PDRM). This PDRM is believed to be caused by magnetic orientation during compaction. Paleomagnetic measurements show three regimes that are correlated with the stratigraphic regimes. NRM declination and inclination data show good correlation between the three cores and agree well with the correlations based on sediment character. NRM intensity variations are due largely to the variations in magnetite content and its occurrence as either single detrital grains or as inclusions within the larger silicates. Thus the variation in paleo intensity was not determined. Comparisons of Lake Tahoe data with that from Mono Lake show fair correlations of declination and inclination. The occurrence of a short-wavelength, high-amplitude event in the lower section of the Lake Tahoe cores may provide confirmation of the Mono Lake geomagnetic excursion.
Dodson Richard E.
Henyey Thomas L.
Palmer Donald F.
No associations
LandOfFree
Paleomagnetic and sedimentological studies at Lake Tahoe, California-Nevada 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 Paleomagnetic and sedimentological studies at Lake Tahoe, California-Nevada, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Paleomagnetic and sedimentological studies at Lake Tahoe, California-Nevada will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1446388