Sekwi Formation

{{Infobox rockunit

| name = Sekwi Formation

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| period = Cambrian

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| type = Formation

| age = {{Fossil range|Atdabanian|PS=(approx.)|ref={{Cite book|url=https://books.google.com/books?id=TGftJkWUs4oC&dq=%22ingta%22+formation&pg=PA1 | title=Geological Survey of Canada, Current Research (Online) no. 2006-A4 | first1=K. | last1=Dewing | last2=Sharp | first2=R J | last3=Ootes | first3=L | last4=Turner | first4=E C | last5=Gleeson | first5=S| year=2006 | isbn=9780662431343 }}}}; Fallotaspis, Nevadella, and Bonnia-Olenellus trilobite zones

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| region = Northwest Territories

| country = Canada

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| underlies = *Hess River Formation

• Rockslide Formation

| overlies = *Vampire Formation

• Backbone Ranges Formation
• Ingta Formation (where the above are absent)

| thickness = 700 m

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The Sekwi Formation is a geologic formation in Northwest Territories, Canada, which preserves fossils dating back to the Cambrian period.

The formation principally comprises shallow water carbonates, but deepens to include mid-shelf mudstones, both calcareous and siliciclastic.{{cite journal |last1=RANDELL |first1=ROBERT D. |last2=LIEBERMAN |first2=BRUCE S. |last3=HASIOTIS |first3=STEPHEN T. |last4=POPE |first4=MICHAEL C. |title=New Chancelloriids From the Early Cambrian Sekwi Formation With a Comment on Chancelloriid Affinities |journal=Journal of Paleontology |date=September 2005 |volume=79 |issue=5 |pages=987–996 |doi=10.1666/0022-3360(2005)079[0987:NCFTEC]2.0.CO;2|s2cid=130292492 }}

It dates from c. 525-510 Ma, the Nevadella / Bonnia-Olenellus trilobite zones.{{Cite journal | doi = 10.1016/j.palaeo.2007.02.031| title = Stable isotope geochemistry of the lower Cambrian Sekwi Formation, Northwest Territories, Canada: Implications for ocean chemistry and secular curve generation| year = 2007| last1 = Dilliard| first1 = K.A.| last2 = Pope| first2 = M.C.| last3 = Coniglio| first3 = M.| last4 = Hasiotis| first4 = S.T.| last5 = Lieberman| first5 = B.S.| journal = Palaeogeography, Palaeoclimatology, Palaeoecology| volume = 256| issue = 3–4| pages = 174–194}}