CAPE TOWN, South Africa—In geology, old is gold.

According to the local mining lore here, senior geologists tend to do their work the old-fashioned way. They avoid radar technology, preferring instead to examine termite and ant mounds; they study vegetation and carry divining rods. They're famous in the often cutthroat industry for their efficiency—also for wearing neckties in the blistering heat.

"I...