Login
Login

Bloyd Formation

{{Short description|Geologic formation in Arkansas, United States}}

{{Infobox rockunit

| name = Bloyd Formation

| image = Hustedia brentwoodensis opening.jpg

| caption = Fossil from the Bloyd Formation

| type = Formation

| age = Pennsylvanian

| period = Pennsylvanian

| prilithology = Shale

| otherlithology = Sandstone, limestone

| namedfor = Bloyd Mountain, Washington County, Arkansas{{cite journal |last1=Purdue|first1=A.|title=Description of the Winslow quadrangle|journal=U.S. Geological Survey Geologic Atlas of the United States|date=1907|volume=154|pages=2, 3}}

| namedby = Albert Homer Purdue

| region = Arkansas

| country = United States

| coordinates =

| unitof =

| subunits = Baldwin coal,{{cite journal |last= Croneis |first= Carey |title= Geology of the Arkansas Paleozoic area |journal= Arkansas Geological Survey Bulletin |date= 1930 |volume= 3 |url= http://geology.ar.gov/pdf/Bulletin-3_Geo_AR_Paleozoic_text.pdf |access-date= 2018-01-28 |archive-url= https://web.archive.org/web/20170125100922/http://geology.ar.gov/pdf/Bulletin-3_Geo_AR_Paleozoic_text.pdf |archive-date= 2017-01-25 |url-status= dead }} Brentwood Member, Dye Shale Member, Kessler Limestone Member, Parthenon Sandstone Member,{{cite journal |last1=Chandler |first1=Angela |last2= Zachry |first2=Doy |title= Parthenon Sandstone: a prominent new member of the Morrowan Bloyd Formation, Pennsylvanian of north-central Arkansas (abstract) |journal= Geological Society of America Abstracts with Programs |date=2010 |volume=42 |issue=2 |page=70 |url= https://gsa.confex.com/gsa/2010NC/finalprogram/abstract_170665.htm |accessdate= 28 January 2018}} and Woolsey Member{{cite journal |last1=McFarland |first1=John David |title=Stratigraphic summary of Arkansas |journal=Arkansas Geological Survey Information Circular |date=2004 |origyear=1998 |volume=36 |page=14 |url=http://geology.ar.gov/pdf/IC-36_v.pdf |access-date=2018-01-28 |archive-url=https://web.archive.org/web/20161221195953/http://www.geology.ar.gov/pdf/IC-36_v.pdf |archive-date=2016-12-21 |url-status=dead }}

| underlies = Atoka Formation

| overlies = Hale Formation

| thickness =

| extent =

| area =

| map =

| map_caption =

}}

The Bloyd Formation, or Bloyd Shale, is a geologic formation in Arkansas. It preserves fossils dating back to the Carboniferous period.

Stratigraphy

The Bloyd Formation conformably overlies the Hale Formation and unconformably underlies the Atoka Formation. Five formal and one informal members are recognized in the Bloyd Formation (in stratigraphic order):

  • Kessler Limestone Member
  • Dye Shale Member
  • Parthenon Sandstone Member (also known as the "middle Bloyd sandstone"){{cite journal|last1=Chandler|first1=Angela|last2=Zachry|first2=Doy|title=Parthenon Sandstone: a prominent new member of the Morrowan Bloyd Formation, Pennsylvanian of north-central Arkansas|journal=Geological Society of America Abstracts with Programs|date=2010|volume=42|issue=2|page=70|url=https://gsa.confex.com/gsa/2010NC/finalprogram/abstract_170665.htm|accessdate=27 May 2018}}
  • Woolsey Member
  • Baldwin coal (an informal unit at the top of the Woolsey Member)
  • Brentwood Limestone Member

In the eastern parts of the Ozarks in Arkansas, the Bloyd Formation becomes undifferentiated with the underlying Hale Formation and is called the Witts Springs Formation.

Paleontology

=[[Brachiopod]]s=

{{col-begin|width=75%}}

{{col-1-of-2}}

:A. newberryi{{cite journal|last1=Henry|first1=Thomas W.|last2=Sutherland|first2=Patrick K.|title=Brachiopod biostratigraphy of Morrowan series (Pennsylvanian) in northwestern Arkansas and northeastern Oklahoma|journal=Oklahoma Geological Survey Guidebook|date=1977|volume=18|pages=107–115|url=http://ogs.ou.edu/docs/guidebooks/GB18.pdf|accessdate=1 February 2018}}

:A. coloradoensis

:H. brentwoodensis

{{col-2-of-2}}

:L. nodosus

:R. magnicosta

:T. formosa

{{col-end|width=75%}}

=[[Bryozoa]]ns=

{{col-begin|width=75%}}

{{col-1-of-3}}

  • Anisotrypa{{cite journal|last1=Horowitz|first1=Alan S.|title=Late Mississippian and Early Pennsylvanian bryozoan faunas of Arkansas and Oklahoma: a review|journal=Oklahoma Geological Survey Guidebook|date=1977|volume=18|pages=101–105|url=http://ogs.ou.edu/docs/guidebooks/GB18.pdf|accessdate=3 February 2018}}
  • Coscinotrypa

:C. fayettevillensis

:C. gracilens

:F. morrowensis

:F. serratula

:F. venusta

:G. crassitoma

:M. triseriata

{{col-2-of-3}}

:P. anastomosa

:P. constricta

:P. elliptica

:P. kesslerensis

:P. magna

:P. purduei

:P. triseriata

:P. washingtonensis

:P. cribosa

:P. concava

{{col-3-of-3}}

:R. attenuata

:R. lepidodendroides

:R. snideri

:R. tabulata

:S. implexa

:S. reversispina

:S. brentwoodensis

:S. sinuomarginata

:T. tuberculata

{{col-end|width=75%}}

=[[Cephalopod]]s=

{{col-begin|width=75%}}

{{col-1-of-4}}

: A. modulus{{cite journal|last1=Saunders|first1=W. Bruce|last2=Manger|first2=Walter L.|last3=Gordon Jr.|first3=Mackenzie|title=Upper Mississippian and Lower and Middle Pennsylvanian ammonoid biostratigraphy of northern Arkansas|journal=Oklahoma Geological Survey Guidebook|date=1977|volume=18|pages=117–137|url=http://ogs.ou.edu/docs/guidebooks/GB18.pdf|accessdate=1 February 2018}}

: A. quinni

: B. micromphalus

: B. secundum

: B. scotti

: B. branneri

: C. miseri

: D. neumeieri

  • Euloxoceras{{cite journal|last1=Gordon, Jr.|first1=Mackenzie|title=Carboniferous cephalopods of Arkansas|journal=U.S. Geological Survey Professional Paper|date=1964|volume=460|pages=40–45|url=https://pubs.usgs.gov/pp/0460/report.pdf}}

{{col-2-of-4}}

: G. morrowensis

: G. adaense

: G. araium

: G. attenuatum

: G. branneri

: G. fittsi

: G. depressus

: G. morrowensis

: G. oblatus

: H. crancens

: M. subdivisum

{{col-3-of-4}}

: M. normale

: P. compressum

: P. kesslerense

: P. morrowanus

: P. compressum

: P. kesslerense

: P. arkansiensis

: P. quinni

: P. knoxense

{{col-4-of-4}}

: P. pygmaeum

: P. solidum

: S. smithi

: S. arkansiensis

: S. globosum

: S. oblatum

: V. pygmaeus

: W. smithi

{{col-end|width=75%}}

=[[Conodont]]s=

{{col-start|width=75%}}

{{col-1-of-2}}

: A. gigantus{{cite journal|last1=Grayson Jr|first1=Robert C.|last2=Sutherland|first2=Patrick K.|title=Conodont evidence for unconformity within Trace Creek Shale Member of Bloyd Formation (Lower Pennsylvanian) in northwestern Arkansas and northeastern Oklahoma|journal=Oklahoma Geological Survey Guidebook|date=1977|volume=18|pages=181–184|url=http://ogs.ou.edu/docs/guidebooks/GB18.pdf|accessdate=30 January 2018}}

: A. lautus

: I. sinuosis

: I. convexus

: L. typa

{{col-2-of-2}}

: N. kunamai

: S. minutus

: S. suberectus

{{col-end|width=75%}}

=[[Crinoid]]s=

{{col-start|width=75%}}

{{col-1-of-4}}

: A. grandis{{cite journal|last1=Strimple|first1=Harrell L.|title=Chesterian (Upper Mississippian) and Morrowan (Lower Pennsylvanian) crinoids of northeastern Oklahoma and northwestern Arkansas|journal=Oklahoma Geological Survey Guidebook|date=1977|volume=18|pages=171–176|url=http://ogs.ou.edu/docs/guidebooks/GB18.pdf|accessdate=30 January 2018}}

: A. progressus

: A. girtyi

: A. rotundus

: A. rotundus multibrachiatus

: A. planulatus

: A. rugosus

: A. braggsi

: A. constrictus

: A. dubius

: A. tumulosus

: C. furnishi

: C. symmetricus

: C. circulus

: C. regularis

: C. spinosus

: C. tumidus

{{col-2-of-4}}

: C. grandis

: D. optimus

: D. subaplatus

: D. croneisi

: D. pentanodus

: E. matheri

: G. pirum

: L. daileyi

: L. minutus

: L. multinodus

: L. nodus

: L. strigosus

: L. asymmetricus

: M. aplatus

: M. exotericus

: M. gillumi

: M. papulosus

{{col-3-of-4}}

: M. cockei

: M. spinifer

: M. fosteri

: P. kesslerensis

: P. oklahomensis

: P. aequabilis

: P. caliculus

: P. magnus

: P. magnus

: P. pumilus

: P. teneris

: P. brevis

: P. rosei

: P. conicus

: P. minutus

{{col-4-of-4}}

: P. brentwoodensis

: S. cascus

: S. crassacanthus

: S. crassibrachiatus

: S. ornatus

: S. pustulosus

: S. hansoni

: S. ornatus

: U. oklahoma

: U. pentanodus

{{col-end|width=75%}}

=[[Flora]]=

:A. missouiense{{cite journal|last1=Groves|first1=John R.|title=Calcareous foraminifers and algae from the type Morrowan (Lower Pennsylvanian) region of northeastern Oklahoma and northwestern Arkansas|journal=Oklahoma Geological Survey Bulletin|date=1983|volume=133|pages=65|url=http://ogs.ou.edu/docs/bulletins/B132.pdf|accessdate=3 February 2018}}

:C. aliquantulus

  • Donezella
  • Eflugelia
  • Girvanella{{cite journal|last1=Nodine-Zeller|first1=Doris E.|title=Microfauna from Chesterian (Mississippian) and Morrowan (Pennsylvanian) rocks in Washington County, Arkansas, and Adair and Muskogee Counties, Oklahoma|journal=Oklahoma Geological Survey Guidebook|date=1977|volume=18|pages=89–99|url=http://ogs.ou.edu/docs/guidebooks/GB18.pdf|accessdate=3 February 2018}}

:G. minuta

:S. spissa

=[[Foraminifera]]=

{{col-begin|width=75%}}

{{col-1-of-3}}

:A. rugosus

:C. adherens

:D. inaequalis

:E. donbassicus

{{col-2-of-3}}

:H. harltoni

:M. marblensis

:M. pressa

:M. transitorius

:P. pinguis

:P. evoluta

{{col-3-of-3}}

:T. maxima

:T. minima

:T. plana

:T. multivolutus

{{col-end|width=75%}}

=[[Ostracod]]s=

:A. confluens{{cite journal|last1=Knox|first1=Larry W.|title=Morrowan (Lower Pennsylvanian) ostracodes from Arkansas and Oklahoma|journal=Oklahoma Geological Survey Guidebook|date=1977|volume=18|pages=139–147|url=http://ogs.ou.edu/docs/guidebooks/GB18.pdf|accessdate=31 January 2018}}

:A. nodosus

:A. rothi

  • Bairdiolites{{cite journal|last1=Sohn|first1=I. G.|title=Late Mississippian and Early Pennsylvanian ostracoda from northern Arkansas - a preliminary survey|journal=Oklahoma Geological Survey Guidebook|date=1977|volume=18|pages=149–159|url=http://ogs.ou.edu/docs/guidebooks/GB18.pdf|accessdate=31 January 2018}}
  • Hollinella

:H. bassleri

:K. bendensis

:K. jolliffana

=[[Sponge]]s=

:H. sphaericum{{cite journal|last1=Rigby|first1=J. Keith|last2=Manger|first2=Walter L.|title=Morrowan lithistid demosponges and hexactinellids from the Ozark Mountains of northwestern Arkansas|journal=Journal of Paleontology|date=14 July 2015|volume=68|issue=4|pages=734–746|doi=10.1017/S0022336000026184|s2cid=131850370 }}

:S. hadra

:V. ichnata

=[[Trace fossil|Trace Fossils]]=

:C. arkansanus{{cite journal|last1=Branson|first1=Carl C.|title=New records of the Scyphomedusan Conostichus|journal=Oklahoma Geology Notes|date=May 1961|volume=21|issue=5|pages=130–138|url=http://ogs.ou.edu/docs/geologynotes/GN-V21N5.pdf|accessdate=28 January 2018}}

=[[Incertae sedis]]=

:A. cordillerensis

:C. laevis

:P. strigosa

See also

{{Portal|Paleontology}}

References

{{reflist}}

  • {{cite web|title= Fossilworks: Gateway to the Paleobiology Database|author= ((Various Contributors to the Paleobiology Database))|url= https://www.fossilworks.org|access-date= 17 December 2021}}

Category:Pennsylvanian Arkansas

Category:Carboniferous southern paleotropical deposits

Category:Shale formations of the United States

Category:Sandstone formations of the United States

Category:Limestone formations of the United States