Stretching about 1,000 kilometers (700 miles), the Sierra Madre Oriental is a range of folded mountains in northeastern Mexico. Formed about 60 million years ago, the mountains are composed of limestone and shale and contain major deposits of copper, lead, and zinc. Some peaks rise more than 3,600 meters (12,000 feet).
The image above shows the rugged folds and valleys of the Sierra Madre Oriental. The image was acquired on October 28, 2020, by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite. The mountain range runs adjacent to several large cities, including Monterrey (capital of Nueva León state) and Saltillo (capital of Coahuila state).
The Sierra Madre Oriental is one of three main mountain ranges surrounding the Mexican Plateau, which covers much of northern and central Mexico. Each range bears the name “Sierra Madre”—Spanish for “Mother Mountain Range.” The Sierra Madre Occidental stands along the western side of the plateau, Sierra Madre del Sur lies to the south, and Sierra Madre Oriental stands on the east. The Sierra Madre Oriental connects with the Sierra Madre Occidental through the Trans-volcanic Mexican belt.
The Sierra Madre Oriental is part of a chain of nearly continuous mountain ranges from North America to West Antarctica known as the American Cordillera. Derived from the Spanish word cordilla—meaning “little rope,”—the Cordillera forms the western “backbone” of North, South, and Central America and can be traced through the Andes all the way to the mountains of Graham Land on the Antarctic Peninsula. The Sierra Madre Oriental is often thought to be an extension of the Rocky Mountains, which are cut by the Rio Grande near the Texas-Mexico border.
The Sierra Madre Oriental is well known for its dynamic ecosystems. Habitats in the north are characterized by a desert climate, influenced by the Chihuahuan Desert to the west. Rainfall increases to the south, creating a tropical forest environment at higher elevations. The region is dominated by pine-oak forests, which grow at altitudes between 1,000 and 3,500 meters (3,000 feet to 11,500 feet) above sea level. The mountains are home to many mammals, including the mule deer, puma, and jaguar.
NASA Earth Observatory image by Joshua Stevens, using MODIS data from NASA EOSDIS/LANCE and GIBS/Worldview. Story by Kasha Patel.