Highland Lakes geology layered with the ancient past
Retired geophysicist Charles Beierle at Lookout Mountain in Kingsland. The stone behind him was most likely formed by an ancient ocean’s rapidly changing tides and is probably 250 million years old. Staff photo by Dakota Morrissiey
You don’t have to be a world-class geophysicist to appreciate the crumbling limestone canyons and granite mountains that merge in the heart of Texas, said Charles Beierle, a retired geophysicist, but it doesn’t hurt to know a little about how it got to be so dang beautiful.
The Highland Lakes area rests at the collision of ancient, volcanic granite that has stood for billions of years and contains the limestone bones of a long-dead ocean.
“The thing that impressed me about the area is that you could drive from Austin to Inks Lake and you’d be traversing 2 billion years of geologic history and never have to get out of the car,” he said.
As a boy growing up in Missouri, Beierle often walked with his grandfather along the banks of the Missouri River, visiting some of the homeless men who congregated there. Most rode the rails like the hobos of the Depression, something his grandfather had experienced in his earlier life.
“Most of these guys were World War II veterans,” Beierle said. “I didn’t think anything of it. It wasn’t abnormal.”
Eventually, he rode his bike to visit what was known as the “hobo jungle” on his own. One of the rail riders he spoke with had a college education but couldn’t hold a job because of shell shock from fighting in the war. He knew a lot about geology and passed it on to young Beierle.
“I was maybe 9 or 10 years old, able to build a bicycle, and we were standing there looking at this outcrop of Burlington limestone and there were graphic images of crinoids and brachiopods,” he said. “I thought to myself that these were postcards from the past. That’s when I really became interested in geology, which later led to geophysics.”
He carried that moment with him into adulthood, pursuing a career in geophysics, the study of the physical processes and properties of Earth. He worked for petroleum companies for decades before retiring in Kingsland. Beierle has been giving geology lessons to the Highland Lakes chapter of the Master Naturalists on and off for the past 11 years.
He chose to retire in Kingsland specifically because of its geological formations. Lookout Mountain, which acts as an eastern boundary to the lakeside community, is one of the formations that drew him to the area. Standing before the massive hunk of black sandstone as traffic whizzed past, Beierle delved into the rock’s ancient history.
“What you’re seeing here is about 250 million years of geologic history,” he said.
At one time, this stone would have been exposed to a rapidly changing tide from an inland sea that stretched into the heart of Texas. Millions of years of sand eventually compacted into stone, trapping thousands of fossils within its layers and creating vertical stripes, one on top of the other, each marking an era.
The limestone of eastern Burnet County is another remnant of the vast inland sea that fascinates Beierle. The white, chalky canyons and hills that make up the Balcones Escarpment are the remains of a titanic geological upheaval that forced huge layers of limestone up and out of Earth’s surface. These formations are literally made from the shells of ancient creatures that roamed the sea floor about 100 million years ago.
“There were some hellacious earthquakes along the Balcones Escarpment,” Beierle said.
The escarpment stretches from Del Rio to Dallas, passing through Austin and San Antonio. It is considered the dividing line between the coastal plain to the east and Edwards Plateau to the west, where bigger, older rocks — and the Highland Lakes — lie.
The hills of the Hill Country actually used to be mountains as tall as the Swiss Alps, towering over the valleys at 12,000 to 14,000 feet. They eroded over 2.5 billion years to their current formations.
The granite scattered around Enchanted Rock, Granite Shoals, Granite Mountain, Reveille Peak Ranch, and Inks Lake all come from the same granite batholith, an igneous formation that plunges deep into Earth’s crust. Formed from cooling magma, the pink granite batholith that runs underground connecting Granite Mountain to Enchanted Rock is the second-largest formation of its kind in the United States. The largest, the High Sierra, includes Yosemite Valley in Central California.
Beierle plans to continue passing on his ample knowledge to anyone interested in learning it.
“You don’t need a graduate course, you just need to understand that this stuff is there,” he said. “You can look at the ground and see that these processes have been going on for 2.5 billion years, at least.”
After an afternoon standing alongside a massive slice of rock cut away from a mountain by human-made machinery, this reporter drove home to Llano wondering how many billions of years were passing by on Texas 29.