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Geophysical investigations of coastal magnetite sands at Meleman, Lumajang, East Java

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Magnetic, gravity, resistivity and refraction seismic surveys were made in a 2.5 km2 coastal area of titaniferous magnetite sand deposits at Meleman village, East Java. Magnetic anomaly data are consistent with models having an average susceptibility of 2.5 x 10 emu/cm? and negligible remanent magnetization with shapes of observed dunal topography or buried lenses less than 10 m thick. Bouguer gravity anomaly data suggest that alluvium and low-density sedimentary rocks may be 3 km thick in the survey area;, that low-density alluvium less than SO m thick covers an undulating surface of density contrast which may represent buried drainage topography perpendicular to the present coastline; and that high-density magnetite sand is restricted to part of a dunal ridge about 10 m high. Resistivity data show a zone of salt water penetration of resistivity
0.1 to 5 ohm-m and a zone of higher resistivity which may represent a ridge of low permeability sediments
beneath the salt water layer. Seismic data indicate that alluvial velocities average about 1800 m/sec and that an undulating refractor separating materials of velocities I 650 m/sec and 1950 m/sec may !be vertically offset about 20 m upward at a depth of 35 m.
Test borings limited to depths of about 10 m show a positive correlation between the most iron-rich deposits and amplitudes of magnetic anomalies. We conclude that magnetic surveys may be profitably used in conjunction with borehole surveys for identifying shallow sand deposits having potenti:al value as a source of iron. Gravity, resistivity, and seismic surveys are useful in estimating depth extents of deeper sand and gravel deposits having potential value as paving or construction materials.

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Ketersediaan

Informasi Detail

Judul Seri

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No. Panggil

PK No. 5

Penerbit

Bandung : Direktorat Geologi., 1975

Deskripsi Fisik

25p.,ill. 14 x 21 cm

Bahasa

English

ISBN/ISSN

-

Klasifikasi

NONE

Tipe Isi

text

Tipe Media

unmediated

Tipe Pembawa

other (unmediated)

Edisi

-

Subjek

Magnetite Sands
Meleman
Lumajang

Info Detail Spesifik

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Pernyataan Tanggungjawab

Direktorat Sumber Daya Mineral

Informasi Lainnya

Kode Wilayah

-

Pulau Dan Lembar Peta

Lainnya

Provinsi

Sumatera Utara

Koordinat - Latitude

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Koordinat - Longitude

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Versi lain/terkait

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