TITLE:
Magnetic Method Surveying and Its Application for the Concealed Ore-Bodies Prospecting of Laba Porphyry Molybdenum Ore Field in Shangri-La, Northwestern Yunnan Province, China
AUTHORS:
Nguyen Ba Dai, Chuan Dong Xue, Kun Xiang, Kun Xiang, Tran Trong Lap, Qureshi Javed Akhter, Shi Lei Li
KEYWORDS:
Magnetic Method, Physical Property Parameters, Concealed Ore-Bodies Prospecting, Laba Porphyry Molybdenum (-Copper) Ore Field, Northwestern Yunnan Province
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.2 No.3,
June
12,
2014
ABSTRACT: Recently, a number of large molybdenum (-copper)
deposits have been discovered successively in the Laba area, Shangri-La county,
northwestern Yunnan province. The investigation confirmed that there is a
superlarge porphyry-skarn hydrothermal vein type molybdenum-polymetallic- metallogenic
system with the total prediction reservoir of more than 150 mt molybdenum. The
porphyry intrusions contributed to the mineralization closely, the superficial
little vein molybdenum (-copper, lead, silver) ore-bodies are usually located
in faults and fractures, and the deep porphyry type ore-bodies occurred in the
granodiorite porphyries, the skarn type ore-bodies occurred in the contact zone
intrused into Triassic limestone or Permian basalts. Laba ore block is a new
exploration area with great prospecting potential. In order to reduce the
target area and guide the further exploration work, the magnetic method
measurement about 3.3 square kilometres was carried out in the ore field. This
paper presents an application of analyzing the horizontal and vertical
derivative, using Fast Fourier Transform (FFT) filter (FFT high-pass, low-pass,
cosine roll-off, suscepbility), calculated spectra frequency energy to predict
the depth and intensity of the apparent remanence magnetization of source
(Hilbert). The calculated results and magnetic anomalous show that the
remanence anomaly is caused by the intrusions into the Triassic limestone and
Permian basalts with small anomalies, and the depth of located source is not
great. We have identified a number of positions to the three drilled well, the
drilled result specify interpretation with very high accuracy. The magnetic
method is helpful to identify porphyry mineralization, and judge the shape and
depth of the concealed ore-bearing intrusive bodies under the similar geological
condition.