Cenomanian Coniacian zonation (foraminifers and calcareous algae) in the Guerrero Morelos basin, southern Mexico
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Universidad Nacional Autónoma de México
2003
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| author | Noemí Aguilera Franco |
| author_facet | Noemí Aguilera Franco |
| contents | Cenomanian Coniacian zonation (foraminifers and calcareous algae) in the Guerrero Morelos basin, southern Mexico Noemí Aguilera Franco Ciencias de la Tierra basin Mexico zonation Coniacian Cenomanian A biostratigraphic zonation of the CenomanianConiacian rocks of the GuerreroMorelos basin(southern Mexico) is proposed. The stratigraphic distribution of 70 species of calcareous algae andbenthic and planktonic foraminifers is used to characterize four Zones that in ascending order are:Pseudorhapydionina dubia TRZ (Total Range Zone); Whiteinella archaeocretacea IRZ (Interval RangeZone); Helvetoglobotruncana helvetica TRZ, and Marginotruncana sigali IRZ.The top of P. dubia (upper Cenomanian) is marked at the last appearance of the marker fossil,which closely corresponds to the last appearance of most miliolid benthic foraminifers. Over most of thearea, the transition from shallowmarine limestones up into pelagic facies occurs within the W.archaeocretacea Zone (uppermost Cenomanianlowermost Turonian). A characteristic of this zone isthe scarcity of both benthic and planktonic foraminifers, including the zonal marker. Most large benthicforaminifers disappear in the lower part of this zone. The changes observed within the W. archaeocretaceaZone reflect the successive stages of the platform drowning.The H. helvetica (lowermiddle Turonian) is characterized by the presence the nominal taxon,dicarinellids, praeglobotruncanids, whitenelids and hedbergelids. This zone is recognized in the MexcalaFormation and represents deposition in fully pelagic conditions. Toward the central and eastern part ofthe area in shallowopen marine facies (Cuautla Formation), this zone is represented by an assemblagecharacterized by hippuritids, echinoids (crinoids and roveacrinids), gymnocodiacean and udoteaceanalgae and scarce planktonic foraminifers.The Marginotruncana sigali (upper TuronianConiacian) was defined with the last appearanceof H. helvetica, whilst its top was difficult to recognize. Toward the central and eastern part of the area,this zone is represented in shallowopen marine facies (Cuautla Formation) by an assemblage dominatedby the hippuritid Vaccinites gosaviensis, solitary corals, gymnocodiacean algae, calcisphaerulids andvery scarce planktonic foraminifers.The CenomanianTuronian boundary lies in the lower part of the Cuautla Formation. Theappearance of hippuritid mollusks and the diversification of whiteinellids can be used to mark thisboundary. 2003 artículo científico 1026-8774 https://www.redalyc.org/articulo.oa?id=57220304 en http://www.redalyc.org/revista.oa?id=572 Revista Mexicana de Ciencias Geológicas application/pdf Universidad Nacional Autónoma de México Revista Mexicana de Ciencias Geológicas (México) Num.3 Vol.20 |
| format | Artículo científico |
| id | redalyc_57220304 |
| institution | Redalyc |
| language | en |
| publishDate | 2003 |
| publisher | Universidad Nacional Autónoma de México |
| spellingShingle | Cenomanian Coniacian zonation (foraminifers and calcareous algae) in the Guerrero Morelos basin, southern Mexico Noemí Aguilera Franco Ciencias de la Tierra basin Mexico zonation Coniacian Cenomanian Cenomanian Coniacian zonation (foraminifers and calcareous algae) in the Guerrero Morelos basin, southern Mexico Noemí Aguilera Franco Ciencias de la Tierra basin Mexico zonation Coniacian Cenomanian A biostratigraphic zonation of the CenomanianConiacian rocks of the GuerreroMorelos basin(southern Mexico) is proposed. The stratigraphic distribution of 70 species of calcareous algae andbenthic and planktonic foraminifers is used to characterize four Zones that in ascending order are:Pseudorhapydionina dubia TRZ (Total Range Zone); Whiteinella archaeocretacea IRZ (Interval RangeZone); Helvetoglobotruncana helvetica TRZ, and Marginotruncana sigali IRZ.The top of P. dubia (upper Cenomanian) is marked at the last appearance of the marker fossil,which closely corresponds to the last appearance of most miliolid benthic foraminifers. Over most of thearea, the transition from shallowmarine limestones up into pelagic facies occurs within the W.archaeocretacea Zone (uppermost Cenomanianlowermost Turonian). A characteristic of this zone isthe scarcity of both benthic and planktonic foraminifers, including the zonal marker. Most large benthicforaminifers disappear in the lower part of this zone. The changes observed within the W. archaeocretaceaZone reflect the successive stages of the platform drowning.The H. helvetica (lowermiddle Turonian) is characterized by the presence the nominal taxon,dicarinellids, praeglobotruncanids, whitenelids and hedbergelids. This zone is recognized in the MexcalaFormation and represents deposition in fully pelagic conditions. Toward the central and eastern part ofthe area in shallowopen marine facies (Cuautla Formation), this zone is represented by an assemblagecharacterized by hippuritids, echinoids (crinoids and roveacrinids), gymnocodiacean and udoteaceanalgae and scarce planktonic foraminifers.The Marginotruncana sigali (upper TuronianConiacian) was defined with the last appearanceof H. helvetica, whilst its top was difficult to recognize. Toward the central and eastern part of the area,this zone is represented in shallowopen marine facies (Cuautla Formation) by an assemblage dominatedby the hippuritid Vaccinites gosaviensis, solitary corals, gymnocodiacean algae, calcisphaerulids andvery scarce planktonic foraminifers.The CenomanianTuronian boundary lies in the lower part of the Cuautla Formation. Theappearance of hippuritid mollusks and the diversification of whiteinellids can be used to mark thisboundary. 2003 artículo científico 1026-8774 https://www.redalyc.org/articulo.oa?id=57220304 en http://www.redalyc.org/revista.oa?id=572 Revista Mexicana de Ciencias Geológicas application/pdf Universidad Nacional Autónoma de México Revista Mexicana de Ciencias Geológicas (México) Num.3 Vol.20 |
| title | Cenomanian Coniacian zonation (foraminifers and calcareous algae) in the Guerrero Morelos basin, southern Mexico |
| topic | Ciencias de la Tierra basin Mexico zonation Coniacian Cenomanian |
| url | https://www.redalyc.org/articulo.oa?id=57220304 |