Yes, I hope so. We are using GoogleEarth in area south of here to help with big-scale relationships, but I would LOVE to be able to see bed-scale resolution. Some researchers have done stuff w/ LIDAR and/or draping high-res photomosaics on DEMs and such.

SF asks: “If these beds were somehow repeated by imbricate thrusting or some other complication (sometime in the far future), do you think you could tell which sandstone section or sections you were in because of the overall characteristics of the beds?”

Most likely not. Unless there was some marker bed/horizon w/ very unique features or geochemistry or something. There are some areas in this outcrop belt where there is some repetition and it’s recognized by mapping the fault itself. The throw is minor (10-20 m) so arguing that the succession is repeated is believable.

SF asks: “Would microfossils be required to do this feat of correlation?”

That would be nice … but, the time between sandstone-rich units would probably have to be fairly significant such that different biozones are represented. Turbiditic successions can pile up relatively rapidly thus generating a rather thick succession all within a single biozone. Additionally, the preservation of microfossils in turbidites is highly variable. In this particular area, on top of all that, the nearby Miocene magmatic event cooked the forams ever so slightly such that recognition of different species is problematic.

SF asks: “How far along strike or downdip do you think these types of beds could be correlated if they were broken up or repeated?”

In this particular formation, one doesn’t not have to go very far to see big changes. In some cases, a couple hundred meters … at most a couple kilometers. These sandstone bodies are highly lenticular and variable over short distances. In other settings, where the beds go for several to 10s of km, the ability to correlate single beds goes up. For example, the Marnoso-Arenacea outcrops in Italy are interpreted to represent a “basin plain” environment and some individual beds can be correlated for 20-30 km (according to some workers).

SF asks: “And do sandstone-mudstone turbidite sequences ever get mixed up with limestone beds, with limestones somehow being part of the sequences?”

Yes, although it’s typically over thicker intervals (alternating at scales of 100s of meters) … I’m not sure if I’ve seen a succession where carbonates and siliclastics alternate bed by bed. Maybe some other readers have.

Hopefully that addressed your questions … let me know if not.

In some places we simply couldn’t get across safely (e.g., a steep cliff) so we used the photomosaics in concert with binoculars to observe and document the relationships.

Brian do you think in the future applications like Google earth with terrain (3D tilt) may help in doing a pre-fieldwork rough guide to stratal relationships?