Chapel Island Formation

{{Short description|Sedimentary formation in Newfoundland, Canada}}

{{Infobox rockunit

| name = Chapel Island Formation

| image = Cambrian GSSP in Chapel Island Formation.jpg

| caption = Ediacaran–Cambrian boundary section at Fortune Head, Newfoundland, in the Chapel Island Formation. The darker units constituting the bottom 2–3 m of the outcrop correspond to Unit 1; the GSSP lies a couple of meters into Unit 2.

| period = Cambrian

| type = Formation

| age = {{Geological range| Ediacaran | Fortunian| refs={{cite journal|doi=10.1017/S001675680100509X |title=Burrowing below the basal Cambrian GSSP, Fortune Head, Newfoundland |journal=Geological Magazine |volume=138 |issue=2 |year=2001 |last1=Gehling |first1=James G. |last2=Jensen |first2=Sören |last3=Droser |first3=Mary L. |last4=Myrow |first4=Paul M. |last5=Narbonne |first5=Guy M.|pages=213–218|url=http://www2.coloradocollege.edu/dept/gy/pmyrow/Publications/Gehling.pdf |accessdate=3 November 2012 |archiveurl=https://web.archive.org/web/20141028190903/http://www2.coloradocollege.edu/dept/gy/pmyrow/Publications/Gehling.pdf |archivedate=28 October 2014 |bibcode=2001GeoM..138..213G}}}}

| prilithology =

| otherlithology =

| namedfor =

| namedby =

| region = Newfoundland

| country = Canada

| coordinates =

| unitof = Young's Cove Group{{Cite web | url=http://geoatlas.gov.nl.ca/Default.htm|title=Newfoundland and Labrador Geoscience Atlas}}

| subunits =

| underlies = Random Fm

| overlies = Rencontre Fm

| thickness = Hundreds of metres

| extent =

| area =

| map = Chapel Island Formation map.svg

| map_caption = Outcrop distribution in southeast Newfoundland

}}

The Chapel Island Formation is a sedimentary formation from the Burin Peninsula, Newfoundland, Canada. It is a succession of siliciclastic deposits, over {{convert|1000|m|ft}} thick, that were deposited during the latest Ediacaran and earliest Cambrian.

Stratigraphy

The formation's sequence stratigraphy is detailed in a journal article by Myrow and Hiscott.{{cite journal|last1=Myrow|first1=Paul M.|last2=Hiscott|first2=Richard N.|title=Depositional history and sequence stratigraphy of the Precambrian-Cambrian boundary stratotype section, Chapel Island Formation, southeast Newfoundland|journal=Palaeogeography, Palaeoclimatology, Palaeoecology|date=September 1993|volume=104|issue=1–4|pages=13–35|doi=10.1016/0031-0182(93)90117-2}} The formation starts in an intertidal zone, then, as the Cambrian progresses, becomes deeper water (outer shelf) as a general trend.

The Chapel Island Formation lies on top of the Rencontre Formation and below the Random Formation. It is {{convert|900|m|ft}} thick in Fortune Bay as a fault-bounded basin, consisting of grey-green siltstones and sandstones, with minor limestone beds near its top. Small shelly fossils have been recovered – primitive taxa only. The setting is nearshore or open shelf.{{cite journal|last1=Smith|first1=Simon A.|last2=Hiscott|first2=Richard N.|title=Latest Precambrian to Early Cambrian basin evolution, Fortune Bay, Newfoundland: fault-bounded basin to platform|journal=Canadian Journal of Earth Sciences|date=December 1984|volume=21|issue=12|pages=1379–1392|doi=10.1139/e84-143|bibcode=1984CaJES..21.1379S}}

Subdivisions

The formation is divided into six members, numbered 1 to 5, with Member 2 split into 2A and 2B. The Proterozoic–Cambrian boundary occurs {{convert|20.66|m|ft}} above the base of the formation, {{convert|2.4|m|ft}} into Member 2A.

The lowest occurrence of Treptichnus pedum in the succession is {{convert|16.25|m|ft}} above the base of the unit.

Chapel Island Formation

Stratigraphy

Subdivisions

See also

References

Further reading