Lithologic Character of the Paleozoic Sandstone Succession, Southern Ozark Region, Arkansas, and Missouri

Abstract Mafic-ultramafic plutonic intrusions form an early phase in the emplacement of the predominantly granitic Vioolsdrif Suite, which together with its extrusive carapace, the Orange River Group, form the Richtersveld Magmatic Arc, a Palaeoproterozoic crustal segment formed between 1910 and 1865 Ma. Their lithologic character and distinctive dark weathering features in the mountain desert landscape of the Richtersveld, neighbouring regions of the Northern Cape Province and southern Namibia, make them a separate mappable unit in what is a predominantly granitic terrain. The name of the subsuite is taken from a spectacular twin peak massif near Goodhouse (Vuurdoodberg), while the type locality is one of the best preserved central-type intrusive bodies at Swartkop, situated 2 km off the N7 highway about 20 km south of the border town of Vioolsdrif, where the rock types present include gabbro, metagabbro, quartz-metagabbro, peridotite and troctolite.

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Effects of the lithologic character of manufactured sand on properties of concrete

Journal of Wuhan University of Technology-Mater Sci Ed ◽

10.1007/s11595-014-1070-9 ◽

2014 ◽

Vol 29 (6) ◽

pp. 1213-1218 ◽

Cited By ~ 2

Author(s):

Jiliang Wang ◽

Zhifeng Yang ◽

Yihan Liu

Keyword(s):

Manufactured Sand ◽

Lithologic Character

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MAGNETIC WELL LOGGING

Geophysics ◽

10.1190/1.1437736 ◽

1952 ◽

Vol 17 (1) ◽

pp. 1-26 ◽

Cited By ~ 15

Author(s):

R. A. Broding ◽

C. W. Zimmerman ◽

E. V. Somers ◽

E. S. Wilhelm ◽

A. A. Stripling

Keyword(s):

Electrical Conductivity ◽

Magnetic Susceptibility ◽

Drilling Fluid ◽

Well Logging ◽

Simultaneous Recording ◽

General Assumption ◽

Total Field ◽

Magnetic Well ◽

Lithologic Character

The need for control data in interpretation of surface magnetometer surveys has led to the development of borehole instruments for measuring magnetic susceptibility and total magnetic field in situ. The susceptibility instrument is an alternating current induction device, and by separation of the quadrature components simultaneous recording of the magnetic susceptibility and the electrical conductivity is possible. The susceptibility log has many features that depart from ordinary electric logs. The instrument has a sensitivity of the order of [Formula: see text] cgs units and sufficient contrast has been found in the sediments to yield a log of considerable lithologic character. This magnetic character suggests the use of the susceptibility tool in the field of special well logging, particularly for geologic correlation, and for tracer studies. The general assumption that the magnetic susceptibility of the sediments is sufficiently low compared to basic igneous rocks so that sedimentary rocks have little effect on surface magnetometer measurements has been verified. Since the magnetic susceptibility and electrical conductivity logs are made with an induction instrument, an electrolyte is not required in the hole and the logs are independent of the drilling fluid, except that the conductivity log is influenced by highly conductive muds. The total field log is made with a three element self‐orientating saturable core magnetometer that has been developed for borehole use. This log has not been used extensively. In addition to reflecting changes in polarization of the formations, it is influenced by formation susceptibility. Logs have been made of the total field going into and through igneous plugs. The paper presents examples of these logs along with a brief description of the instruments developed to produce them.

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