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| JELINITE, AMBER, FROM ELLSWORTH COUNTY, KANSAS, KIOWA FORMATION (CRETACEOUS). COLLECTION OF GLENN ROCKERS. |
I was able to attend the recent 45th
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.