AGS Fieldtrip – Mason Mill Park

Field Trip: Mason Mill Park

Our next AGS field outing will be on Sunday, March 23 to Mason Mill Park, a 12-minute drive from our monthly meeting site at Fernbank Museum. As with the 2023 and 2024 AGS trips to the Davidson-Arabia Mountain Nature Preserve, the outing is in cooperation with DeKalb County Parks and Recreation. Like those trips, this will be a crowdsource discovery trip.

The goal is to use the Rockd app (developed with NSF funding at U. Wisconsin) to log all the park’s outcrops. For fun, we will split into two teams. “Blizzards” (participants with November through April birthdays), will have a friendly competition with “Hurricanes” (May through October birthdays) to see who can log the most outcrops.

We’ll begin at 9:30 in the center of the park, by visiting three outcrops from which we have thin sections. One exposes a non-foliated granitic intrusion, and the other two expose gneiss, one with contorted foliation. To crowdsource interpreting the thin sections, see the “AGS Fieldtrips” Google Drive folder at this link, where you can add comments in the PDF file containing 24 new images from those three outcrops.

Each team will be assigned to explore roughly half of the park’s trail network looking for outcrops. In the park, there are many rock and saprolite exposures – in rail cuts, along streambanks, eroded trails, and elsewhere. We’ll reconvene a few hours later to assimilate what we learned. The outcrop logging is simple. For example, collecting a strike and dip is easier than ever with the app.

To signup for the event click here