ORIGIN OF HEMATITE CARRYING A LATE PALEOZOIC REMAGNETIZATION IN A QUARTZ SANDSTONE BED FROM THE SILURIAN ROSE HILL FORMATION, VIRGINIA, USA

Paleomagnetic and petrographic studies of a quartz sandstone bed from the Silurian Rose Hill Formation of the Central Appalachians show that hematite carrying a Late Paleozoic remagnetization is authigenic. Com parison of paleopole positions from the Rose Hill Formation with Late Paleozoic poles for North America suggests a synfolding remagnetizatio n. The sandstone cement is characterized by pore-lining hematite, pore -filling berthierine and intergrowths of hematite, berthierine and qua rtz. These cements postdate pressure solution of detrital quartz grain s. Late Paleozoic cementation is a consequence of diagenesis associate d with Alleghanian deformation. Detrital Fe-Mg silicate grains art bel ieved to have been a local source of Fe for some authigenic hematite a nd berthierine, although mass balance calculations suggest that an ext ernal source is also required. Some berthierine aggregates are pseudom orphic after detrital Fe-bearing silicate grains. Trace amounts of det rital tourmaline are the only remnants of the detrital Fe-Mg silicates .