magnetic anomalies

A geological map covering 7000 square nautical miles of solid rock floor of a section of the Eastern English Channel is presented. This map is based on the results of a systematic sampling and continuous reflection profiling (Sparkers) grid. A total of 279 core stations have been manned and 3500 nautical miles of sparkers, magnetometer and echo sounding traverses were carried out. 

What's following hasn't been made up by a solitary, bored holidaymaker wearing a snorkel, one chilly afternoon on Ryde beach. Nooooooooooo.... it took 279 bored and snorkel-equipped holidaymakers!

    The bathymetric data suggest that tidal scour is the important eroding agent because the bathymetry not only illustrates the physical differences between the different sea-bed stratigraphical units but also shows the major structural features. The geological maps show a series of major strike-faulted anticlines and synclines which traverse WSW - ENE, turning E - W. and finally WNW - ESE. These major structures consist of strata ranging in age from Permo-Trias to Tertiary: The strata involved have been folded and faulted during IntraCretaceous and Tertiary movements. 

We had a good look at the bottom of the sea and it's as wrinkled as our most respectable club member's rear end. The only difference is one's wetter than the other...  

    Quantitative interpretation of several of the magnetic anomalies shows that the depth to the basement varies considerably. The differences in depth to the basement are associated with the shallow geological structures. Basement control is therefore suggested to be the cause for the newly mapped offshore structures. 

In places, it's a long way to dig to the rock. Elsewhere, the muck's not so deep.

The English Channel probably consists of, at least, two major depositional areas, the Wessex Basin and the Western English Channel Trough. At times throughout their geological history these basins were probably linked across the western edge of the Wessex Basin. The edge of this basin is probably situated along a line from Start Point to the Cherbourg Peninsula. It is suggested that a series of more positive basement features are present within the Wessex Basin. These features have affected the structural and depositional history of the Mesozoic and Tertiary strata.

The "English"   Channel is full of cr*p that has been churrned for a long time. The IoW happens to be on top of the biggest pile of cr*p and God only knows what's underneath... 
(Well, I might have been overtranslating a little bit, but basically, it doesn't really ttell us WHY there are magnetic anomalies, does it...?) 