Streams erode sediment from their banks. They pick up and transport sediments. As a stream erodes its banks, it creates a V-shaped valley (Figure above). This contrasts with the U-shaped valleys created by glaciers.
Alluvial fan could be the answer. Alluvial fans are cone shaped deposits of sedimentary particles. The particles can be sand. silt, gravel or clay. These land-forms are formed at the mouth of canyons or in valleys where ephemeral streams can occasionally transport material to the mouth of the canyons. An ephemeral stream is one that is created after a shower of rain or other form of precipitation; they are not permanent streams. <span />
Explanation:
Serpentine
- Formation: it forms through serpentinization, a geological low-temperature metamorphic process where low-silica mafic and ultramafic rocks are oxidized and hydrolyzed with water into serpentinite.
- Characteristics: rich in magnesium and water, light to dark green, greasy-looking and slippery feeling. It can resist the transfer of heat. A source of asbestos, architectural stone, ornamental stone, gem material
- Minerals present: it follows the formula (X)2-3(Y)2O5(OH)4 where X can be magnesium, iron, nickel, aluminum, zinc, or manganese; and, Y will be silicon, aluminum, or iron.
Green Schist
- Formation: they form by regional metamorphism of mafic igneous rocks through depth of burial, and proximity to batholiths.
- Characteristics: The green is due to abundant green chlorite
- Minerals present: actinolite and epidote mainly, but they can also include quartz, orthoclase, talc, carbonate minerals, and amphibole.
Basalt Pillow
- Formation: it forms when lava of basaltic compositions erupted underwater. The rapid cooling of the lava forms the pillow-shaped bodies.
- Characteristics: they are volcanic igneous rocks, very dark, almost black color.
- Minerals present: Basalt has a lower percentage of silica and a higher percentage of iron and magnesium than other volcanic rocks.
Umber
- Formation: it develops in Cyprus massive sulfide deposits.
- Characteristics: is not one precise color, but a range of different colors, from medium to dark, from yellowish to reddish to grayish depending on the iron oxide and manganese in the clay
- Minerals present: contains iron oxide and manganese oxide and sulfide precipitates like pyrite.
I hope you find this information useful and interesting! Good luck!
