Lesson Plan Booster: China’s Rainbow Mountains

Imagine walking through a mountain range where vibrant shades surround you. Reds, yellows and blues look like brightly colored taffy that has melted onto the mountainsides. Are you wandering through an alien planet? No—you’re in China.

Grade level: 7-12

Student learning objectives: Students will examine the Zhangye Danxia Landform in the Gansu Province of northwest China, where layers of compressed sandstone have formed “rainbow mountains” over the past 24 million years. Students will understand the origins of this unique geological phenomenon, a type of landform found only in China.

Preparation

First, define the following terms with, or for, students. (These terms are bolded when they appear in the lesson below.)

Clastic rocks:  Rocks made up of clasts (existing fragments of minerals and rocks).

Composite (conglomerate):  Rock made up of distinct clasts within a matrix.

Cretaceous Age:  The third and final geologic period of the Mesozoic Era. This period is known as the time of origin of many birds, mammals and flowering plants, and also the time of the sudden extinction of many of Earth’s life forms existing between 145.5 and 65.5 million years ago.

Crevasse:  A deep crack in the earth’s surface.

Danxia formations:  Landscapes found in China that are comprised of reddish sandstones and conglomerates formed mostly during the Cretaceous Age.

Deposition:  The natural “depositing” process through which different rocks and minerals get onto, and then become part of, a landform.

Endogenous forces:  Processes, internal to the earth and driven by the warmth of its core, that cause phenomena such as earthquakes, volcanoes and tectonic plate movements.

Exogenous forces:  Processes, external to the earth and driven by the heat of the sun, that cause phenomena such as weathering, erosion, and water and wind movement.

Glauconite:  A greenish mineral of the mica group.

Hematite:  A blackish-red to brick-red mineral, essentially the chief ore of iron.

Geomorphology:  A branch of study that explains how landscapes are formed (i.e., through methods including tectonic plate movements, weathering and deposition).

Sandstone:  A clastic sedimentary rock typically made up mostly of sand-sized feldspar and quartz. 

Sedimentary rocks:  Rocks formed through deposition in water and on land.

Tectonic (plates, movements):  Of or relating to the structure of the earth’s crust and the large-scale processes that take place within it.

Topography:  The surface features of a region, including relative positions and elevations of shapes and structures.
 

Next, introduce students to China’s rainbow mountains.

The Zhangye Danxia (a rough pronunciation is “Chonyay Dangsha”) Landform originated from a base of red sandstone (a sedimentary rock), which became layered with minerals through more than 24 million years of deposition during the Cretaceous Age. This layering resulted in multiple rock colors as millions of years’ worth of clastic rocks formed and became composites, on top of sandstone beds and each other.

Photos of the landform—particularly those taken after rain, when the colors are at their most vibrant—are often mistaken for fakes due to their unusual and striking appearance. View more images here, here and here. An amazing large-size image appears here.

The red color is caused by the iron-rich mineral hematite, which oxidized (“rusted”) when the rocks were formed. The yellow colors are probably due to the presence of sand and clay, and the bluish-greenish-gray color may have come from either organic plant matter or a mineral called glauconite found in marine environments. 

The topography of these Danxia formations, which includes many cliffs and crevasses, occurred when each layer was pushed and manipulated by the same tectonic plates that created large parts of the Himalayan mountains. (The movement of tectonic plates in land formation is a type of endogenous force.) The geomorphology was finalized by weathering, with harsh winds and heavy rains putting the finishing touches (pillars, valleys, etc.) on the land. (Weathering is a type of exogenous force.)

Introducing discussion to students

Landscape changes occur because the right geological circumstances occur in a certain place and at a particular time. Sometimes the circumstances are so unique that they create a topography that exists nowhere else in the world. This is the case with the Zhangye Danxia Landform in China. We’re going to learn about how these mountains got their unusual appearance, and about some of the geologic forces that contributed to their formation.

Options for student discussion questions and activities

• (After discussing the geology vocabulary words) Ask each student (or ask groups of students) to choose a term and use it in a sentence about the formation of the Zhangye Danxia Landform. (Students can choose a particular image of the landform and use it as inspiration for their sentence.)
• Of what other famous geological formations or landscapes are you aware? (Examples include these rock formations and these examples of “earth art”.) How were these landscapes formed? What do these landscapes have in common with the Zhangye Danxia Landform? How are these landscapes different from each other?
• What would it be like to visit the landform in person? (Students can share orally or write a descriptive paragraph as a homework assignment.)
• What do geologists do? (Students can do a little research here.) Would you be interested in a career in geology? Why or why not?
   

Article by Jason Papallo, Education World Social Media Editor
Education World®    
Copyright © 2013, 2015 Education World