Variation of Rock Magnetic Parameters and Paleointensities over a Single Holocene Lava Flow

摘要: A recent (2000 BP) lava flow from central Mexico has been sampled along a vertical profile with 55 cores covering total thickness of 6.6 m. wide range physical and magnetic parameters have studied to characterise the samples: Curie temperature saturation magnetisation as intrinsic properties; density, susceptibility remanence intensity bulk Konigsberger Q-factor hysteresis coercivity parameters. All vary smoothly over profile, most probably due grain size variation minerals present in samples. Optical observations indicate that main opaque are deuterically oxidised titanomagnetites (C3-C5) ilmenites (R2-R3), which increase away edges flow. Paleointensity (PI) was determined using double heating Thellier-Thellier method pTRM checks. According reliability (f-, g-, q-factor) obtained PIs reasonable good quality. PI shows marked position flow, across about 25 125 μT, samples having between 50 100 μT. The flow-mean 72 μT is higher than day field, consistent global data for this time-period. No obvious correlation could be found any other measured parameter. may show some systematic behaviour. It important, therefore, sample both horizontally vertically order obtain reliable paleointensity.