GeoLogic Mapping C

[elephantower]

What is Bowen's Reaction Series?

[boomvroomshroom]

More of a Rocks and Minerals question, but... (Click to Show Hidden Text)

Describes what different types of minerals crystallize from different temperatures of magma. Can be used to help predict how complex the silicate structure is, and thus if they will weather faster. Typically minerals at the top are characteristic of mafic (dark, low-silica content) igneous rock.

[Magikarpmaster629]

It's been a few days, I'll revive this.


A strata is layered

.....Cs/Oc/Dc.....

What is the unconformity?

[boomvroomshroom]

Admittedly, I have no idea what those stand for... (Click to Show Hidden Text)

but if they're all horizontal sedimentary layers, then it must be a disconformity?

[Magikarpmaster629]

Disconformity is right, but not for the reason I was looking for. The letters mark geologic periods, and there is a gap in time between the Ordovician (Oc) and the Devonian (Dc). Because of the gap in time, there must have been a period of time during the Silurian (between Ordovician and Devonian) where there was no deposition and much erosion, making it a disconformity. I should have made that clearer, sorry.

Your turn.

[boomvroomshroom]

What do the little c's stand for? (The book I have has Cambrian = funky C with two lines, Ordovician=O, and Devonian=D.)

Anyway...

What is the standard scale on a USGS map?

[Magikarpmaster629]

1:24,000

[boomvroomshroom]

yep! your turn

[Magikarpmaster629]

Explain the principle of original horizontality.

[boomvroomshroom]

Sediment deposits horizontally, chronologically, bottom to top. In other words, rock layers on the bottom are older than rock layers on top (barring any events that change the scene).