Publication Date:
2023-08-28
Description:
In the Philipsburg district, in western Montana a low arch of a Paleozoic limestones has been cut and deformed on the east and a south sides by a small batholith of Tertiary granodiorite. The manganese deposits are confined to an area of about 2 square miles underlain by sedimentary rocks and adjacent to the granodiorite body. The ore, chiefly pyrolusite, was apparently derived from rhodochrosite that was abundant in the veins and had replaced the adjacent limestones. The oxide ore is found chiefly within 600 feet of the surface, though one small body was mined at a depth of 700 feet. Commonly these bodies are aggregates of nodules or spheroids that range in size from that of an egg to that of a coconut or larger. In some places they show an irregular texture somewhat like that of a sponge, and in others the material composing them is loose and friable and apparently structureless. Psilomelane is the principal constituent of many of the nodules, in which it forms layers that alternate with softer oxides.
Keywords:
AlgonquinMine_P; BryantMine_P; Comment; Deposit type; Depth, bottom/max; DEPTH, sediment/rock; Depth, top/min; Description; Digging pit; DPIT; Elevation of event; Event label; File name; Latitude of event; Longitude of event; NOAA and MMS Marine Minerals Geochemical Database; NOAA-MMS; Philipsburg, Montana; Position; Quantity of deposit; Sample ID; Sediment type; Size; Uniform resource locator/link to image
Type:
Dataset
Format:
text/tab-separated-values, 26 data points
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