Evidence for long intervals of normal polarity during the cretaceous period

Paleointensity results from the Jurassic: New constraints from submarine basaltic glasses of ODP Site 801C

“…They observed a gradual increase in anomaly amplitude from at least as early as anomaly M29 extending to around M20 (158-146 Ma, according to the timescale of Gradstein et al [2004]) which they argue explains the ''Jurassic Quiet Zone'' observed in marine magnetic anomalies in the western Pacific Ocean. This behavior is in stark contrast to the ''Cretaceous Quiet Zone'' which was thought to be a period with no polarity reversals spanning millions of years [Helsley and Steiner, 1969] possibly associated with high magnetic field intensities [Tauxe and Staudigel, 2004;Tarduno and Cottrell, 2005;Tauxe and Yamazaki, 2007].…”

Paleomagnetism of Late Cretaceous alkaline rocks in the Nemuro Peninsula, Hokkaido, N.E.Japan.

“…The present results also suggest that the transitional field reversals also occurred in the Late Cretaceous and the time required for the field transition was probably short on the basis of the assumption that the field reversal probably occurred during the cooling process of the relatively thin intrusive body. Many authors suggest a long interval of time of predominantly normal geomagnetic field polarity in the Late Cretaceous (SASAJIMA and SHIMADA, 1966;HELSLEY and STEINER, 1968;MCELHINNY and BUREK, 1971;LARSON and PITMAN, 1972;PECHERSKY and KHRAMOV, 1973;IRVING and COUILLARD, 1973). The geologic time ranges of the normal interval suggested by these authors differ to some extent as represented in Fig.…”

“…y. +) on the basis of the stratigraphic correlation was called Akoh zone (SASAJIMA and SHIMADA, 1966;HELSLEY and STEINER, 1968;MCELHINNY and BUREK, 1971). PECHERSKY and KHRAMOV (1973) suggested the presence of a reversed zone (Kuldjin zone) in the Jalal normal Interval.…”

Paleomagnetism of Leg Sediment Cores

“…Two previously unreported magnetic reversals in the Coniacian are indicated by these samples. The Coniacian had previously been considered to be part of the Upper Cretaceous long period of normal polarity (Helsley and Steiner, 1969). McKenzie and Sclater (1971) indicate the presence of two reversed events near the beginning of anomaly 33 from sea-floor spreading evidence.…”