Refer from Quran :
Surah Rahman 25:53
وَهُوَ الَّذِى مَرَجَ الْبَحْرَيْنِ هَـذَا عَذْبٌ فُرَاتٌ وَهَـذَا مِلْحٌ أُجَاجٌ وَجَعَلَ بَيْنَهُمَا بَرْزَخاً وَحِجْراً مَّحْجُوراً
Surah Rahman 25:53
وَهُوَ الَّذِى مَرَجَ الْبَحْرَيْنِ هَـذَا عَذْبٌ فُرَاتٌ وَهَـذَا مِلْحٌ أُجَاجٌ وَجَعَلَ بَيْنَهُمَا بَرْزَخاً وَحِجْراً مَّحْجُوراً
And it is He Who has let free the two seas: one palatable and sweet, and the other salty and bitter; and He has set a barrier and a complete partition between them.
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Allah is great.