Diagenetic sources of stable remanence in remagnetized Paleozoic cratonic carbonates: a rock magnetic study

Hysteresis measurements, Lowrie-Fuller tests, Cisowski tests, and low-temperature demagnetization experiments on samples of the Knox Dolomite, Trenton Limestone, and Onondaga Limestone indicate that the remanence in these remagnetized carbonate units resides principally in single-domain magnetite, in contrast to previous interpretations. Volumetrically, however, a significant fraction of the magnetite is coarser grained, as previous scanning electron microscopic work on magnetic extracts has shown. The two components of natural remanence in these rocks are interpreted as 1) a late Paleozoic (Kiaman) chemical remanence carried by single-domain diagenetic magnetite and 2) a Cenozoic thermoviscous overprint residing principally in coarser, pseudosingle domain and multidomain magnetite, also of late Paleozoic diagenetic origin. -from Author