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New Quebec Crater

Andrei wrote:

> I think it is New Quebec Quebec, Canada N 61°17' W 73°40'
> Age:1.4 ± 0.1 Ma 3.44 Km diameter

Steve wrote:

> Your mystery crater is well known. It is:

> New Quebec, Quebec, Canada, Location: 61°17'N, 73°40'W
> Diameter: 3.440 km, Age: 1.40 + 0.10 million years


Hello All,

01) New Quebec Crater synonyms: CHUBB; UNGAVA; PINGUALUIT.

02) The circular structure, 2 miles in diameter was located in July
1950.

03) In 1986, J.Boulger collected a rounded specimen, 1.75 cm across, of
gray, vesicular rock from the shore of Lake Laflamme, about 3 km NNW of
the crater rim. Petrographic analyses of a thin section established its
identity as glass impactite containing numerous grains of quartz with
shock-induced planar features.

04) According to the scale of shock-pressure effects compiled by
Stöffler (1972), impactite with the characteristics observed in the New
Quebec crater will have undergone minimum pressures in the range of 450
to 500 kb.

05) The impact melt samples have a glassy to cryptocrystalline matrix
with minute granular oxides.

06) A chondritic body is favored by the high Cr and siderophiles but the
data are insufficient to assign a class.
The impact melt rocks correspond to a chemical mixture of some of the
local target rocks. They contain enrichments of Ir, Ni, Co and Cr
suggesting that the impacting body was chondritic in composition. The Ir
values, however, are low for a chondritic projectile

07) The conventional Ar39-Ar40 spectrum on a sample has a U-shape. Based
on previous work with melt rocks, the minimum in the U represents a
maximum age of 1.3 Ma for the event.

08) From the best plateau ages , the age of the New Quebec impact is
taken to be 1.4 ± 0.1 Ma, which places it before the first major
northern hemisphere continental glaciation of the Pleistocene.

09) Two leading meteoriticists, F.C. Leonard (1950, 1954) and L. LaPaz
strongly opposed the meteoritic origin of  the crater. They cited New
Quebec and the Lake Bosumtwi Crater as flagrant examples of crater-like
features for which claims of impact origin were made in the absence of
valid field evidence.

Best regards and good night,

Bernd

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