Denise Sofranko, age 13, of Lovilia, Iowa, for her question:
What is Desert Hot Springs?
The place called Desert Hot Springs in California just happens to be one of Andy's favorite hideaways. It is, of course, named for the springs of hot underground water that gush up from the desert ground. Like you, Andy is especially interested in what causes them.
North America has several places named Hot Springs where springs of hot mineral water come up to the surface from deep in the earth. But Andy knows of only one place called Desert Hot Springs. And he knows the place well. It is a small but fast growing town in Southern California, just a few miles from the posh resort called Palm Springs. There the sunny desert slopes northward to higher ground. The scenic location is wondrous to behold, especially if you enjoy the quiet peace of our wide deserts and the calm sunny sky above them.
Standing in or near Desert Hot Springs and facing eastward, you behold an immense panorama of mountains and stretches of rock strewn desert. You are in a huge geological hollow with craggy dark peaks of the San Jacinto Mountains on your left and the giant, often snow capped crown of Mount Gorgonio on your right. The ground on which you stand is warmed by the desert sun but other furnaces are busy warming levels of rock far below the surface. This buried region provides the hot water for the springs and people dig wells to bring more of it to the surface.
The mountains you see are part of the Transverse Range. Our massive western mountains, the Rockies and Sierra Nevada and Coast Ranges, run generally north and south. The Transverse Range runs eastward from the Coast range and bashes head on into the massive slabs of the earth's crust as they start to uplift toward the high Sierra Nevada. A crustal collision of this sort is bound to create complex geological formations both on and far below the surface of the ground. Desert Hot Springs sits right on top of this geological phenomenon.
The Sierra Nevada Range began heaving up its mighty spine about 60 million years ago. Later in this Cenozoic Era, the Coast Range began to grow along the western shores. They were born with seething volcanoes and lava flows, earthquake faults and dramatic shufflings of great crustal slabs. The Transverse Range was an off¬shoot from this remodeling. The peaks you see are its old volcanoes and its lava, rich in minerals, covers the ground. At Desert Hot Springs, the surface of molten lava cooled fast. But below the ground, the heat was sealed away from the cooling breezes. The buried rocks retained their heat. Ground water drains from the slopes and seeps down to fill their pores and pockets. The ground water is heated often to boiling point. In some places, it finds cracks and gushes up in hot springs to the surface. In other places, people drill down to make artificial wells that fill with hot mineral waters.
The formation of the hot springs dates back a million years or so, a mere blink in geological history. The ground water is heated by buried lavas and may be to some extent by pressure and friction in the complex crustal formations below. Lavas are rich in assorted minerals from the earth's interior and even cool water tends to dissolve them. Underground hot water dissolves even more, which explains why the water of the hot springs and wells is loaded with usual and unusual minerals.