Rock Magnetic Properties of Igneous Rock Samples—Leg 45

Paleomagnetism of Middle Jurassic Basalts, Deep Sea Drilling Project Leg 76

“…This study Taylor et al, 1973Marshall, 1978Bleil and Smith, 1980Hall and Ryall, 1977Johnson, 1979Johnson, 1979Faller et al, 1979Faller et al, 1979Faller et al, 1979Faller et al, 1979Faller et al, 1979 Reference This study Taylor et al, 1973Marshall, 1978Levi, 1980Levi, 1980Bleil and Petersen, 1977Johnson, 1979Johnson, 1979Faller et al, 1979Faller et al, 1979Faller et al, 1979Faller et al, 1979Faller et al, 1979 …”

Rock Magnetism of Basement Rocks, Deep Sea Drilling Project Site 417

“…Compared to the average values obtained on other oceanic basalts (Lecaille and Prévot, in preparation;Grommé and Mankinen, 1976;Dunlop and Hale, 1977;Bleil and Petersen, 1977;Petersen et al, 1978, in press;Johnson, 1979;Petersen, 1979;Day et al, 1979), Js is generally higher at Site 417, which bears out the assertion that an unusually large percentage of magnetic minerals is present in the Site 417 basalts. Thus for example, the highly oxidized titanomagnetites found in pillow samples in Holes 417A and 417D cause the samples to have an average Js of 1.38 ±0.88 emu/cm 3 for 17 samples, 1.5 times higher than the average obtained for 53 fresh pillow basalt samples from the FAMOUS area (0.87 ±0.11 emu/cm A positive correlation is observed at Site 417 between Js and JNRM (Figure 8) for pillows and massive basalt samples from Hole 417A, and for pillows from Hole 417D.…”

“…from different locations in the world oceans, the geometric mean intensity of magnetization, JNRM, is generally between 1 and 3 × 10' 3 emu/cm 3 (Lowrie [1974] on several legs in the Pacific and in the Atlantic Ocean; Grommé and Mankinen [1976] and on Leg 34; Bleil and Petersen [1977], Dunlop and Hale [1977], Murthy et al [1977], and Ryall et al [1977] on Leg 37; Petersen et al [1978] on Legs 42 and43; Johnson [ 1979] on Leg 45; Peterson [ 1979] on Leg 46). Basalts from Leg 49 have a slightly higher average JNRM as can be expected for young material drilled close to the Mid-Atlantic Ridge axis (Day et al, 1979).…”

Rock Magnetism and Paleomagnetism of Basalts Drilled during Deep Sea Drilling Project Leg 65

“…~ 0.62; Johnson, 1979). The somewhat higher average f c values appear to be related to oxidation of primary titanomagnetite.…”

“…4A). As can be seen in Figure 1 and Table 4, the reheated samples from the holes drilled on Leg 65 vary for the most part from 120 to 220°C, average T c = 180°, and thus approach values typical of primary titanomagnetite of ocean basalts (Johnson, 1979). In the subsequent heatings of samples to 600 °C the curve J s vs. T becomes practically reversible.…”