Changes

==Anomalies and lateral migration==

==Anomalies and lateral migration==

If the structural or geologic setting of the area suggests that microseepage may be predominantly lateral or pathway selective, such as along dipping stratigraphic surfaces and [[Unconformity|unconformities]], the interpretation will be more difficult since geochemical anomalies may then not be located vertically above a trap. Which of these migration scenarios is more likely in your area of investigation? What is the relationship of the anomalies to outcrop geology, mapped structural closures, stratigraphic pinch-outs, faults, or basement highs? Because relationships between surface geochemical anomalies and subsurface [[accumulation]]s can be complex, proper interpretation requires integration of surface geochemical data with geologic, geophysical, and hydrologic data. The importance of such integration cannot be overstated.<ref name=ch18r46>Thrasher, J., A., Fleet, A., J., Hay, S., J., Hovland, M., Duppenbecker, S., 1996, [http://archives.datapages.com/data/specpubs/memoir66/17/0223.htm Understanding geology as the key to using seepage in exploration: the spectrum of seepage styles], in Schumacher, D., Abrams, M., A., eds., Hydrocarbon Migration and Its Near-Surface Expression: [http://store.aapg.org/detail.aspx?id=75 AAPG Memoir 66], p. 223–241</ref>

If the structural or geologic setting of the area suggests that microseepage may be predominantly lateral or pathway selective, such as along dipping stratigraphic surfaces and [[Unconformity|unconformities]], the interpretation will be more difficult since geochemical anomalies may then not be located vertically above a trap. Which of these migration scenarios is more likely in your area of investigation? What is the relationship of the anomalies to [http://www.merriam-webster.com/dictionary/outcrop outcrop] geology, mapped structural closures, stratigraphic pinch-outs, faults, or basement highs? Because relationships between surface geochemical anomalies and subsurface [[accumulation]]s can be complex, proper interpretation requires integration of surface geochemical data with geologic, geophysical, and hydrologic data. The importance of such integration cannot be overstated.<ref name=ch18r46>Thrasher, J., A., Fleet, A., J., Hay, S., J., Hovland, M., Duppenbecker, S., 1996, [http://archives.datapages.com/data/specpubs/memoir66/17/0223.htm Understanding geology as the key to using seepage in exploration: the spectrum of seepage styles], in Schumacher, D., Abrams, M., A., eds., Hydrocarbon Migration and Its Near-Surface Expression: [http://store.aapg.org/detail.aspx?id=75 AAPG Memoir 66], p. 223–241</ref>

==Hydrocarbon composition from macroseeps==

==Hydrocarbon composition from macroseeps==