Petrology Field Trip, 1997

Photos from Petrology Field Trip, Spring 1997

Stop 1. View from atop Mt. Scott. Spheroidal outcrops are Mt. Scott granite. Note how one nub is split along a joint (near front right).

Left: At Alternate Stop 2, small apophyses of porphyritic rhyolite (dark color) into granite indicating timing relations between the two lithologies at this outcrop (the rhyolite is younger than the granite). Right: At stop 3: Xenolith of Mt. Scott granite (lower part of otc, greyish color) in Quanah granite. Note pegmatic phase of the Quanah just to right of xenolith and dikelet of Quanah cutting the xenolith.

Left: Stop 3 below dam: Xenolith of rhyolite in Quanah granite. Consider the timing relations between rhyolitic magmas and granitic expressed in this and the previous photos. The felsic magmatic event appears to have undergone a protracted time period with phases of extrusion, intrusion, erosion, and hypabyssal intrusion. Right: Students cross dam after viewing outcrops.

Sunrise from top of knob within walking distance of camp.

I-35 road cut: Algal stromatolites with hummocky cross section (seen just above knife). These provide not only paleoenvironmental information, but also indicate facing in this structurally deformed area.

Although this was a Petrology field trip, students could not help getting into some of the neat structures seen in this excellently exposed section of the Arbuckles!

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