Kettle Concretion

Kettle Concretion

Kettle Point ,Ontario

Upper Devonian And Early Mississippian

Collected Legally From the Water At Kettle Point By Another Collector By Using A Boat

Size 28 cm Long X 19.5 cm Wide X 15 cm high

Hopefully when prepped there is an armored fish (Placoderm ) in the center .

Geologic Setting

The famous "kettles" from Kettle Point on Lake Huron (Fig. 1) occur in a modest 2m high shoreline outcrop that extends laterally for approximately 150 m, exposing 5 m of the lower part of the Kettle Point Formation. This outcrop is a provincial historic site in the Kettle Point Indian Reserve and special arrangements were necessary in order to retrieve samples for study. The Kettle Point Formation of southwestern Ontario is part of an extensive black shale sequence that covered much of the eastern United States and parts of central Canada during the Upper Devonian and Early Mississippian. This unit is organic rich, containing up to 15% by weight organic carbon. Studies of the organic matter in the sequence has shown that the organic matter is thermally immature to marginally mature and has neither generated nor lost significant hydrocarbons. The most abundant minerals in the Kettle Point Formation are quartz, averaging 50 weight %, and illite, averaging 22 weight %. Other minerals include feldspar, chlorite, pyrite, dolomite and calcite, the latter of which forms the concretions in the lower part of the formation. Calcareous fossils are generally absent but algal cysts (notably Tasmanites), fragmentary plant material, and minor other fossils such as fish scales and fish teeth may be found. The organic-rich nature of the sediments and low diversity fossil content of these strata has been interpreted to indicate deposition in an oxygen-depleted sea in which water depths may have varied from 50 m to several hundred meters.