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Endapan Plaser

Dalam geologi, endapan plaser ialah akumulasi mineral ekonomis yang terpisah secara alamiah oleh pengaruh gravitasi selama proses sedimentasi. Placer berasal dari bahasa Spanyol yang berarti alluvial sand. Penambangan plaser merupakan sumber utama diperolehnya emas dan merupakan cara yang utama digunakan pada tahun-tahun awal gold rush. Endapan plaser ada yang disebut alluvium, eluvium, plaser pantai, dan paleoplaser.

Material endapan plaser harus memenuhi 2 syarat, yaitu memiliki massa jenis yang besar dan resisten terhadap proses pelapukan. Partikel mineral plaser harus memiliki densitas yang lebih besar daripada kuarsa (2,65), sebagai partikel dominan material pasir dan gravel.  Endapan plaser umumnya mengandung black sand, yang merupakan campuran dari oksida besi berwarna hitam, kebanyakan berupa magnetite dengan ilmenite dan hematite yang jumlahnya bervariasi. Komponen mineral ekonomis yang sering ditemukan bersama black sand ialah monazite, rutile, zircon, chromite, wolframite, dan cassiterite.

Mineral ekonomis lain yang ditambang dari endapan plaser di antaranya:

  • Intan
  • Emas
  • Garnet
  • Besi, dari pasir besi yang mengandung magnetite dalam konsentrasi tinggi
  • Logam kelompok platina
  • Quartz Monazite Sands
  • Unsur tanah jarang, dari mineral monazite
  • Ruby
  • Sapphire
  • Thorium, dari mineral monazite
  • Timah, dari mineral cassiterite
  • Titanium, dari mineral ilmenite dan rutile
  • Uranium, dari paleoplacer berumur Prakambrium
  • Zirconium, dari mineral zircon

Alluvial placers terbentuk pada endapan sungai. Posisi keterdapatan placer emas ialah di bagian dalam lengkungan sungai atau anak sungai, di lembah, pada slopebreak sungai, pada dasar gawir, air terjun, atau jenis penghalang yang lain.

Alluvial placers terbentuk melalui deposisi partikel berat pada suatu titik yang kecepatan arusnya di bawah ambang batas minimum kecepatan untuk mentransport partikel tersebut.

Untuk dapat membentuk endapan plaser yang ekonomis¸ partikel mineral ekonomis harus memiliki densitas yang berbeda cukup besar dengan material gangue-nya. Dengan begitu, akan didapatkan akumulasi mineral ekonomis dalam konsentrasi yang tinggi.

Adapun Beach placers terbentuk oleh endapan pasir dan gravel di sepanjang tepi dari tubuh air yang besar, laut atau danau.

6 thoughts on “Endapan Plaser

  1. Hey, how’s it going?

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  2. Hey, how’s it going?

    Did you hear that the powers that run this world want to put a RFID microchip in our body? It will contain not only our bank accounts but our personal information, making us total slaves to the elite. This will cause us to lose even more of our privacy.

    Did you know that this RFID microchip matches perfectly with the Mark of the Beast in the Bible, more specifically Revelation 13:16-18?

    “He causes all, both small and great, rich and poor, free and slave, to receive a mark on their right hand or on their foreheads, and that no one may buy or sell except one who has the mark or the name of the beast, or the number of his name…”

    Referring to the last days, this could only be speaking of a cashless society, which we have yet to see, but are heading towards. Otherwise, we could still buy or sell without the mark amongst others if physical money was still currency. It’s amazing that the Bible foretold a cashless society!

    Did you also hear that the Jewish people are in the process of bringing about the Third Temple prophesied in the Bible by the prophet Daniel, Jesus, and Apostle Paul? They deny Jesus as their Messiah and say their Messiah will be revealed to rule the whole world under a one world religion. They are not even hiding this information, but are actually promoting it. You can view videos about this on YouTube.

    When Donald Trump made Jerusalem captial of Israel in late December 2017, the Jewish people said this was a big step for them to build this Third Temple. They even printed a Temple coin with president Trump’s face on the front with king Cyrus'(the man who built the Second Temple in the Bible) face behind him. On the back of the coin is an image of the Third Temple. They are selling these coins to raise money to build the Temple.

    People have been saying for many years that the end is near, but we needed not only the Third Temple, but also the technology for there to be a cashless society for the Mark of the Beast to be a reality.

    There is much more to know, please visit http://WWW.BIBLEFREEDOM.COM to see all the proof!

    GOD BLESS, JESUS LOVES YOU!

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