Keywords: Geomagnetic polarity 0-169 Ma PT.svg Geomagnetic polarity over the past 169 Ma trailing off into the en Jurassic Quiet Zone Dark areas denote periods of normal polarity light areas denote reverse polarity Geomagnetic_polarity_0-169_Ma svg 16 36 27 January 2011 UTC Anomie š” Geology timelines Geomagnetism |