Preliminary Results of Investigations made to Study the use of Indian Pottery to Determine the Paleointensity of the Geomagnetic Field for United States 600-1400 A. D.

Wobbling Motion of the Geomagnetic Dipole Field in Historic Time During These 2000 Years

“…First, Brynjolfson (1957) illustrated four minor loops, appearing at 800, 1000, 1300 and 1800 A.D, respectively, whilst Kawai et al (1965) were the second to have shown three loops appearing at 800, 1300 and 1800 A.D. Aitken (1962) has inferred similar movements at 1300 and 1800 A.D. although his curve does not make a complete loop. In the old data obtained by Chevallier (1925), from Sicily, the same movement has also been revealed, while in the results of DuBois and Watanabe (1965), from Arizona, one can recognize at least one loop in the period around 1300 A.D.…”

“…In Fig. 2 is shown the movement of the virtual pole position obtained from the above mentioned observatories whose localities are shown in 1, 7 and 9 : after Bauer (1899) and Vestine et al (1947), 2 : after Brynjolfson (1957), 3: after Aitken et al (1963) 4: after Chevallier (1925, 5 and 8: after Cox and Doell (1960), 6 : after Watanabe (1959), Yukutake (1962) and Kawai et al (1965),10: after DuBois and Watanabe (1965),11: after Burlatskaya (1961 In order to construct a working model from which we can develop a comprehensive explanation of the clockwise secular and the anticlockwise archaeo-secular variation, we hereby propose a quasi-hypotrochoid motion of the dipole axis around the rotational axis of the earth. This is a combined motion of two rotations and is represented by a point on a rotating disc whose centre is simultaneously describing a circular orbit.…”

“…Although records of the variation from geomagnetic observatories extend back in time only some two or three hundred years, we can actually acquire data on the secular field over a much greater time range by utilizing an elegant method pioneered by Thellier (1936), by which he succeeded in extracting ancient geomagnetic fields fossilized in ancient baked clays. Studies along the above-mentioned line of thought have been carried out in several parts of the world and subsequently pubished in different countries (Brynjolfson 1957, Watanabe 1959, Aitken et al 1962, Yukutake et al 1963, Kawai et al 1965, DuBois and Watanabe 1965.…”

Magnetic paleointensity studies on a recent basalt from Flagstaff, Arizona

“…No disagreement is lherefore observed. This is an indication from the study by DuBois and Watanabe [1965] that the field in this part of the world has not changed much from the present value. This view is supported by the present study and may indicate that the main dipole field has not decreased steadily in the last 2000 years as indicated by others [see Smith, 1967c].…”

MagIC as a FAIR Repository for America's Directional Archaeomagnetic Legacy Data

“…In 1964, geophysicist Robert DuBois began his life‐long pursuit of sampling and measuring archaeomagnetic materials. Within a few years, he had amassed a large enough data set of archaeomagnetic data with associated dates, that he began publishing the first VGP models of paleosecular variation for the Four Corners region (e.g., DuBois, 1989; DuBois, 2008; DuBois & Watanabe, 1965; Watanabe & DuBois, 1965; Weaver, 1967). He used the resulting VGP maps to date archeological sites in the region.…”