questions for thought:
compare and contrast the weatering rate and weathering products foe ca-rich plagiclase in the following localities. 1. central pennsylvania
2. death valley with 2 inches rain per year
3. an alskan mountaiintop where water is frozon ear round
To compare and contrast the weathering rate and weathering products for Ca-rich plagioclase in the provided localities, we need to consider the different environmental conditions each locality presents.
1. Central Pennsylvania:
- Weathering Rate: Central Pennsylvania experiences a temperate climate with a moderate amount of precipitation throughout the year. Rainwater and surface water, combined with temperature fluctuations, contribute to chemical weathering processes. The weathering rate for Ca-rich plagioclase in this locality is expected to be moderate.
- Weathering Products: The weathering products for Ca-rich plagioclase in Central Pennsylvania would mainly consist of clay minerals, such as kaolinite, due to the gradual breakdown of the plagioclase feldspar over time.
2. Death Valley with 2 inches of rain per year:
- Weathering Rate: Death Valley is a desert region with extremely arid conditions. The lack of rainfall significantly limits chemical weathering processes. Therefore, the weathering rate for Ca-rich plagioclase in this locality would be very slow.
- Weathering Products: Due to the limited water availability, the weathering products for Ca-rich plagioclase in Death Valley will be minimal. The plagioclase will mostly remain intact or may undergo minor physical weathering processes, such as abrasion or exfoliation caused by thermal stress.
3. Alaskan mountaintop with frozen water year-round:
- Weathering Rate: The freezing temperatures on the Alaskan mountaintop lead to freeze-thaw cycles, which can cause mechanical weathering through frost wedging. However, the chemical weathering processes are limited in frozen conditions. Therefore, the weathering rate for Ca-rich plagioclase in this locality would be slower compared to a temperate climate.
- Weathering Products: In this frozen environment, the primary weathering product for Ca-rich plagioclase would be small pieces or fragments resulting from mechanical weathering caused by frost wedging. There would be limited chemical alteration of the mineral due to the frozen water conditions.
To summarize, the weathering rates and weathering products for Ca-rich plagioclase differ in these localities. Central Pennsylvania experiences moderate rates of chemical weathering, resulting in the production of clay minerals. Death Valley's minimal rainfall limits both weathering rate and weathering products. The frozen conditions on an Alaskan mountaintop slow down weathering, predominantly leading to mechanical weathering products.