While you're waiting for an answer, did you know we have 300,000 study resources that could answer your question in TSR's Learn together section?
We have everything from Teacher Marked Essays to Mindmaps and Quizzes to help you with your work. Take a look around.
If you're stuck on how to get started, try creating some resources. It's free to do and can help breakdown tough topics into manageable chunks. Get creating now.
Not sure what all of this is about? Head here to find out more.
- Study Helper
Sorry this a late reply, but gravity surveys as you said are conducted by the use of a gravimeter. The gravimeter is used to detect gravitational anomalies within the Earth. Where there is an excess of mass relative to the country rock, a positive anomaly is given (gravitational force is greater in this area compared to the surrounding country rock). On the other hand, where there is a deficit of mass (less gravitational force compared to the country rock average) then a negative anomaly is recorded. Remember that an anomaly is a value that does not fit in with the general pattern.
Gravity surveys are commonly used in oil and mineral exploration as identifying the density of material in an area can potentially tell geologists where oil or ore minerals may be located. For example, salt domes often signify the presence of oil should an oil source rock be located in that area. As salt domes are composed of salts (obviously) they have a lower density compared to the country rock at around 2.3g/cm^3. Salt domes often act as oil traps therefore, if a salt dome is identified during a gravity survey (by exhibiting a negative anomaly) then it is a good spot for oil drilling to take place.
Hope this helps!