JELINITE (AMBER): THE HOLY GRAIL OF KANSAS MINERALS

JELINITE, AMBER, FROM ELLSWORTH COUNTY, KANSAS, KIOWA FORMATION (CRETACEOUS).  COLLECTION OF GLENN ROCKERS.

 I was able to attend the recent 45^th Annual Denver Gem and Mineral Show and found the exhibited specimens quite beautiful.  The Show theme this year was “Copper and Copper Minerals” and varieties of copper-bearing minerals, as well as large hunks of native copper, were spectacularly displayed.  I spent a large amount of time sort of staring into the cases wondering why I could never find such specimens!  I also made the rounds of several dealers and was able to visit with one of my heroes, Bob Jones, the Senior Editor of Rock and Gem Magazine. But, my highlight of the entire Show was getting to see the Holy Grail of Kansas Minerals!

Surficial rocks in Kansas are almost entirely sedimentary—lots of limestones, shales, and sandstones.  Many are quite fossiliferous and excellent collecting opportunities exist for invertebrates of Pennsylvanian, Permian and Cretaceous ages.  However, collectors of specimen minerals often bypass the state.  Mississippian rocks in extreme southeastern Kansas, part of the Tri-State Lead and Zinc District, have produced very nice specimens of galena, dolomite, chalcopyrite, and sphalerite.  Late Paleozoic rocks give up a few geodes with calcite and occasionally celestine.  Cretaceous rocks yield some marcasite and pyrite while the Tertiary and Pleistocene sediments offer numerous types of microcrystalline quartz.  Some outcrops of the Tertiary Ogallala Group have yielded non-gemmy moss opal.  But, generally speaking, Kansas minerals are not “rare” and crystal collectors often head to the east to the Ozarks and Ouachitas, west to Colorado, or north to the Black Hills.

But, there is one Kansas mineral that is quite rare with essentially all of the very few collected specimens coming from a single small locality that is no longer accessible and is now located under several tens of feet of water in a Corps of Engineers reservoir.  That is why I have termed jelinite the Holy Grail of Kansas Minerals!

Jelinite, first described as kansasnite, is actually a type of amber and is a local name honoring the initial collector, George Jelinek, who found the first specimens in 1937-38 along the Smoky Hill River in Ellsworth County, Kansas (Buddhue, 1939a; 1939b).  The amber came from a “layer of soft sulfur-colored clay bounded by two thin lignite layers” (Langenheim and others, 1965).  There was some debate about the exact geological formation that produced the amber and originally specimens were ascribed to the Cretaceous Dakota Formation since this unit contains many more lignite beds than the underlying Kiowa Formation. 

The confusion about the stratigraphic units seems reasonable (at least to me) since at many outcrops in Ellsworth County (and other localities) the rocks appear similar and are difficult to distinguish between.  Bayne and others (1971) noted that: both formations are heterogeneous units of shale, sandstone, and siltstone with pyrite, marcasite, gypsum crystals, ironstone concretions, and lignitized wood fragments. The mostly non-marine Dakota Formation was deposited during the retreat of the Kiowa Sea in a bordering low-lying coastal or deltaic plain.  The underlying Kiowa Formation was deposited in nearshore to coastal environments as the early Cretaceous sea spread northeastward across gentle terrain developed mainly on Permian rocks.  So, the Dakota has sparse nonmarine fossils (such as leaves) in Ellsworth County outcrops while the Kiowa has a few marine gastropods and mollusks.  But, both units have tightly cemented “quartzite” (CaCO₃) lenses (an interesting issue).  It is easy for roadside travelers to confuse the two units without the presence of fossils or a good geologic map. 

 

Both formations have beds of lignite although such beds are thicker and more numerous in the Dakota.  However, detailed mapping of the stratigraphy near Kanopolis Reservoir led Bayne and others (1971) to state “the fossil amber (jelinite) found in the NW SW sec. 18, T. 17 S., R. 6 W. …probably came from such a sequence [carbonaceous clay] in the lower parts of the Kiowa Formation.”  This was a confirmation of previous statements by Langenheim and others (1965).

So, the amber did originate in the Kiowa Formation.  However, with the construction and filling of Kanopolis Reservoir in 1948-1951 covering the collecting locality, any refinement of stratigraphy is destined for the far future.

Schowe (1942) examined specimens of jelinite and described them as "light butterscotch in color or some other shade of brown. It is waxy, shines as if polished, is cloudy to translucent, and is made up of more or less concentric bands somewhat like agate. The amber has a hardness of about 3... It is brittle and breaks with a conchoidal or shell-like fracture.”

Although macrofossils seem absent from the jelinite, Waggoner (1996) reported the presence of sheathed bacteria, amoebae and other microfossils.  The presence of succinic acid (C₄H₆O₄) in jelinite led Buddhue (1938) to suggest a conifer origin for the amber.  Langenheim (1969) noted that almost all Cretaceous ambers from North America came from members of the Araucariaceae (a conifer).

I want to thank Glenn Rockers of Paleosearch Inc., Hays, Kansas, for showing me his specimen, letting me hold the Holy Grail, and for allowing photographs.  Glenn informed me the specimen in his possession was purchased by an unnamed person at an estate auction and was part of the original Jelinek collection.  He also stated there is a much larger specimen floating around in a private collection.  Now, if I could only find an estate auction like that! 

  

REFERENCES CITED

Bayne, C. K., P. C. Franks, and W. Ives, Jr., 1971, Geology and Ground Water Resources of Ellsworth County, Central Kansas: Kansas Geological Survey Bulletin 201.

Buddhue, J. D., 1938a, Some New Carbon Minerals—Kansasite Described: The Mineralogist, v. 6, no. 1. 

Buddhue, J. D., 1938b, Jelinite and Associated Minerals: The Mineralogist, v. 6, no. 9. 

Langenheim, J. H. 1969, Amber-a Botanical Inquiry: Science v. 16, no 3.

Langenheim, Jr., R. L., J. D. Buddhue, and G. Jelinek, 1965, Age and Occurrence of the Fossil Resins Bacalite, Kansasite, and Jelinite: Journal of Paleontology v. 39, no. 2.

Schoewe, W. H. 1942. Kansas Amber: Kansas State Academy of Science, Transactions no. 45.

Waggoner, B. M. 1996, Bacteria and Protists from Middle Cretaceous Amber of Ellsworth County, Kansas: PaleoBios v. 17, no.1.

mike