sentences:  A fore-reef/back-reef transition is the 'sweet spot', and thus depending on the age of the carbonate sequence, familiarity with coral palaeontology is considered essential.Finally, once a basin model of the carbonate sequence is formulated, and the primary basin-margin faults are roughly identified, a gravity survey is often carried out, which is the only geophysical technique which can directly detect MVT deposits.Gravity surveys aim to detect significant accumulations of lead and zinc due to their greater density relative to their surrounding host rocks.