all but one of the following statement about the melting and crystallization of magmas is correct.identify the one statement that is incorrect.
1)the presence of water decreases the melting temperature of magma.
2)the upper part of magma in a magma chamber will be richer in felsic minerals than mafic minerals.
3)sodium rich felspar melts at lower temperatures than calcium rich feldspar .
4)the residue in a magma chamber will become progressively rich in felsic mineral as magma migrates away.
5)mafic magma crystallize at higher temperatures than felsic magmas.
plz help i need the correct answer.thanks
To determine the correct statement among the options given, let's analyze each statement:
1) The presence of water decreases the melting temperature of magma. This statement is correct because water acts as a flux, reducing the melting point of the magma.
2) The upper part of magma in a magma chamber will be richer in felsic minerals than mafic minerals. This statement is generally correct. As magma cools, minerals crystallize and form different layers within the magma chamber. Since felsic minerals have higher melting points, they tend to crystallize closer to the cooler surface, while mafic minerals remain in the deeper part of the chamber.
3) Sodium-rich feldspar melts at lower temperatures than calcium-rich feldspar. This statement is correct, as different minerals have different melting points due to their chemical compositions.
4) The residue in a magma chamber will become progressively rich in felsic minerals as magma migrates away. This statement is incorrect. As magma migrates away from the magma chamber, it undergoes fractional crystallization. This process leads to the removal of the earliest formed minerals, which are generally more felsic. Therefore, the remaining magma becomes relatively enriched in mafic minerals.
5) Mafic magma crystallizes at higher temperatures than felsic magmas. This statement is correct. Mafic magmas are composed predominantly of minerals that crystallize at higher temperatures, while felsic magmas have minerals that crystallize at lower temperatures.
Therefore, the incorrect statement among the given options is:
4) The residue in a magma chamber will become progressively rich in felsic minerals as magma migrates away.
Hence, option 4 is the incorrect statement.