An analysis has been made of archaeointensity data for the past 12 000 years. There are 3243 results from different areas of the world covering the past 12 000 years. Of these, 2203 are from the European region and 1040 are from the rest of the world. The archaeointensity data set analysed in the present study is almost three times larger than that used by McElhinny & Senanayake (1982). Although there is no major difference between our global data and the earlier data, the data for the non‐European region have been improved and we now have a data set for Asia.

A total of 170 ceramic specimens from 16 archaeological sites representing 16 well determined ages from 4000 BC to 150 AD were investigated using the Thellier method. These paleointensities were compared with data from countries near Egypt after reduction to a common latitude to determine a secular variation curve of the geomagnetic field for the time period from 4000 BC to 150 AD. The field intensity increases from about 30 pT around 3500 BC to a maximum of 70 µT at about 400 BC when it starts to decrease until 150 AD. The Thellier double heating method was used together with the following additional test measurements: a) during the Thellier experiments the laboratory field FLsb. pointed in the direction of stable NRM, b) magnetic susceptibility was measured after each double heating step to check for chemical alteration, c) a TRM check was made, by repeating the pTRM induction at a lower temperature, d) recent samples which were fired in a known field were used to test the reliability of our experimental setup and method. Based on rock magnetic measurements magnetite was identified as the predominant carrier of magnetization in the ceramics and bricks.

A total of 115 ceramic specimens out of 41 samples from 9 archeological sites in Giza, Fayoum, Benisuef, El Minia, Malawy, and Sohag were collected. They represent 14 well-determined ages covering the last 6000 years. Rock magnetic properties such as Curie temperature and hysteresis loops have been measured for these samples to identify the magnetic carrier; it is found to be fine-grained magnetite. All specimens were investigated using the classic Thellier double heating technique (Thellier and Thellier, 1959) and the modification after Odah et al. (1995) to obtain the paleointensity data. These paleointensities and the previous results of Odah et al. (1995) were used to improve the secular variation curve of the geomagnetic field in Egypt for the last 6000 years. This curve shows a maximum of 72.8 μT at about 250 AD and a minimum of 33 μT at about 3500 BC. It also shows a general decrease of the magnetic moment during the last 2000 years.

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The whole area to the northeast of Zoser pyramid, Saqqara,Giza,Egypt, is characterized by the distribution of a variety of tomb structures of the1st and 2nd Dynasties.The main objective of undertaking a gradiometer survey is to detect the ancient remains as well as other archeological features hidden in thisimportant area.Agradiometersurvey witharasterof 0.5 m  0.5 mhasbeencarriedoutovera surface area of 100 m Â100 m to achieve the purpose and the magnetic data were processed using Geoplot software in order to obtain high quality images of the hidden structures.The results obtained show the presence ofinterconnected large tomb structures composed of mud-bricks; some otherancient rooms and walls are also present.The historical background of the study area confirms the existence of such tomb structures