Facies and sequence analysis of Miocene open-shelf warm-temperate carbonates in Portimão (Lagos-Portimão Formation, Portugal)

I. Armenteros, C. J. Dabrio, P. Legoinha, J. A. González-Delgado, A. Martínez-Graña, G. Alonso-Gavilán, J. Civis, J. Pais

Research output: Contribution to journalArticle

Abstract

The Lower–Middle Miocene Lagos-Portimão Formation at Portimão, southern Portugal, consists of three main heterozoan carbonate facies: mollusc-rich rudstone in a matrix of skeletal packstone/grainstone (MR), fine-to-medium skeletal packstone/grainstone (SPG), and quartz-rich skeletal packstone (QSP). These facies occur in different arrangements and indicate deposition on a wave-dominated open shelf with a well-established heterozoan fauna, most likely related to increased trophic resources where continent supply and upwelling contributed nutrients. These facies form belts inferred to have lain roughly parallel to the strike lines of the shelf, with the MR occupying the more landward, shallower areas and the SPG and QSP extending progressively offshore on the open shelf. Bryozoan abundance in the QSP facies indicates a deep setting on the middle/outer shelf, whereas the absence of rhodalgal components is attributed to a combination of temperature decrease and seafloor eutrophication during the late Langhian and Serravallian, coeval with the “Middle Miocene climatic cooling”. The large photosymbiont-bearing foraminifers and the absence of calcareous algae and zooxanthellate corals point to deposition under warm-temperate conditions. Two main orders of cyclicity are present. Small-scale sequences, 40–60 cm thick, may represent minor sea-level changes related to fifth-order sequences modulated by (~ 100-kyr) eccentricity forcing. Six large-scale sequences, 3–9 m in thickness, are recognized. Based on LAD and FAD of planktic foraminifers and the occurrence of two erosive surfaces related to major sea-level falls (Lang2/Ser1 and Ser4/Tor1), five Miocene sequences (Bu, L1, S1, S2, and S3) are correlated with third-order eustatic cycles.

Original languageEnglish
Article number33
JournalFacies
Volume65
Issue number3
DOIs
Publication statusPublished - 1 Jul 2019

Fingerprint

grainstone
Miocene
carbonate
quartz
foraminifera
Serravallian
calcareous alga
bryozoan
cyclicity
eccentricity
sea level change
mollusc
eutrophication
coral
upwelling
seafloor
sea level
fauna
cooling
matrix

Keywords

  • Burdigalian
  • Cyclicity
  • Heterozoan carbonates
  • Lagos-Portimão Formation
  • Langhian
  • Open shelf
  • Serravallian
  • Warm-temperate waters

Cite this

Armenteros, I. ; Dabrio, C. J. ; Legoinha, P. ; González-Delgado, J. A. ; Martínez-Graña, A. ; Alonso-Gavilán, G. ; Civis, J. ; Pais, J. / Facies and sequence analysis of Miocene open-shelf warm-temperate carbonates in Portimão (Lagos-Portimão Formation, Portugal). In: Facies. 2019 ; Vol. 65, No. 3.
@article{317c80118e584f31aad7ad73f1e12096,
title = "Facies and sequence analysis of Miocene open-shelf warm-temperate carbonates in Portim{\~a}o (Lagos-Portim{\~a}o Formation, Portugal)",
abstract = "The Lower–Middle Miocene Lagos-Portim{\~a}o Formation at Portim{\~a}o, southern Portugal, consists of three main heterozoan carbonate facies: mollusc-rich rudstone in a matrix of skeletal packstone/grainstone (MR), fine-to-medium skeletal packstone/grainstone (SPG), and quartz-rich skeletal packstone (QSP). These facies occur in different arrangements and indicate deposition on a wave-dominated open shelf with a well-established heterozoan fauna, most likely related to increased trophic resources where continent supply and upwelling contributed nutrients. These facies form belts inferred to have lain roughly parallel to the strike lines of the shelf, with the MR occupying the more landward, shallower areas and the SPG and QSP extending progressively offshore on the open shelf. Bryozoan abundance in the QSP facies indicates a deep setting on the middle/outer shelf, whereas the absence of rhodalgal components is attributed to a combination of temperature decrease and seafloor eutrophication during the late Langhian and Serravallian, coeval with the “Middle Miocene climatic cooling”. The large photosymbiont-bearing foraminifers and the absence of calcareous algae and zooxanthellate corals point to deposition under warm-temperate conditions. Two main orders of cyclicity are present. Small-scale sequences, 40–60 cm thick, may represent minor sea-level changes related to fifth-order sequences modulated by (~ 100-kyr) eccentricity forcing. Six large-scale sequences, 3–9 m in thickness, are recognized. Based on LAD and FAD of planktic foraminifers and the occurrence of two erosive surfaces related to major sea-level falls (Lang2/Ser1 and Ser4/Tor1), five Miocene sequences (Bu, L1, S1, S2, and S3) are correlated with third-order eustatic cycles.",
keywords = "Burdigalian, Cyclicity, Heterozoan carbonates, Lagos-Portim{\~a}o Formation, Langhian, Open shelf, Serravallian, Warm-temperate waters",
author = "I. Armenteros and Dabrio, {C. J.} and P. Legoinha and Gonz{\'a}lez-Delgado, {J. A.} and A. Mart{\'i}nez-Gra{\~n}a and G. Alonso-Gavil{\'a}n and J. Civis and J. Pais",
note = "info:eu-repo/grantAgreement/FCT/5876/147458/PT# KBHV/463AC01,CGL2009-11539 SFRH/BSAB/128044/2016 CGL2014-54818-P",
year = "2019",
month = "7",
day = "1",
doi = "10.1007/s10347-019-0575-2",
language = "English",
volume = "65",
journal = "Facies",
issn = "0172-9179",
publisher = "Springer Science Business Media",
number = "3",

}

Facies and sequence analysis of Miocene open-shelf warm-temperate carbonates in Portimão (Lagos-Portimão Formation, Portugal). / Armenteros, I.; Dabrio, C. J.; Legoinha, P.; González-Delgado, J. A.; Martínez-Graña, A.; Alonso-Gavilán, G.; Civis, J.; Pais, J.

In: Facies, Vol. 65, No. 3, 33, 01.07.2019.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Facies and sequence analysis of Miocene open-shelf warm-temperate carbonates in Portimão (Lagos-Portimão Formation, Portugal)

AU - Armenteros, I.

AU - Dabrio, C. J.

AU - Legoinha, P.

AU - González-Delgado, J. A.

AU - Martínez-Graña, A.

AU - Alonso-Gavilán, G.

AU - Civis, J.

AU - Pais, J.

N1 - info:eu-repo/grantAgreement/FCT/5876/147458/PT# KBHV/463AC01,CGL2009-11539 SFRH/BSAB/128044/2016 CGL2014-54818-P

PY - 2019/7/1

Y1 - 2019/7/1

N2 - The Lower–Middle Miocene Lagos-Portimão Formation at Portimão, southern Portugal, consists of three main heterozoan carbonate facies: mollusc-rich rudstone in a matrix of skeletal packstone/grainstone (MR), fine-to-medium skeletal packstone/grainstone (SPG), and quartz-rich skeletal packstone (QSP). These facies occur in different arrangements and indicate deposition on a wave-dominated open shelf with a well-established heterozoan fauna, most likely related to increased trophic resources where continent supply and upwelling contributed nutrients. These facies form belts inferred to have lain roughly parallel to the strike lines of the shelf, with the MR occupying the more landward, shallower areas and the SPG and QSP extending progressively offshore on the open shelf. Bryozoan abundance in the QSP facies indicates a deep setting on the middle/outer shelf, whereas the absence of rhodalgal components is attributed to a combination of temperature decrease and seafloor eutrophication during the late Langhian and Serravallian, coeval with the “Middle Miocene climatic cooling”. The large photosymbiont-bearing foraminifers and the absence of calcareous algae and zooxanthellate corals point to deposition under warm-temperate conditions. Two main orders of cyclicity are present. Small-scale sequences, 40–60 cm thick, may represent minor sea-level changes related to fifth-order sequences modulated by (~ 100-kyr) eccentricity forcing. Six large-scale sequences, 3–9 m in thickness, are recognized. Based on LAD and FAD of planktic foraminifers and the occurrence of two erosive surfaces related to major sea-level falls (Lang2/Ser1 and Ser4/Tor1), five Miocene sequences (Bu, L1, S1, S2, and S3) are correlated with third-order eustatic cycles.

AB - The Lower–Middle Miocene Lagos-Portimão Formation at Portimão, southern Portugal, consists of three main heterozoan carbonate facies: mollusc-rich rudstone in a matrix of skeletal packstone/grainstone (MR), fine-to-medium skeletal packstone/grainstone (SPG), and quartz-rich skeletal packstone (QSP). These facies occur in different arrangements and indicate deposition on a wave-dominated open shelf with a well-established heterozoan fauna, most likely related to increased trophic resources where continent supply and upwelling contributed nutrients. These facies form belts inferred to have lain roughly parallel to the strike lines of the shelf, with the MR occupying the more landward, shallower areas and the SPG and QSP extending progressively offshore on the open shelf. Bryozoan abundance in the QSP facies indicates a deep setting on the middle/outer shelf, whereas the absence of rhodalgal components is attributed to a combination of temperature decrease and seafloor eutrophication during the late Langhian and Serravallian, coeval with the “Middle Miocene climatic cooling”. The large photosymbiont-bearing foraminifers and the absence of calcareous algae and zooxanthellate corals point to deposition under warm-temperate conditions. Two main orders of cyclicity are present. Small-scale sequences, 40–60 cm thick, may represent minor sea-level changes related to fifth-order sequences modulated by (~ 100-kyr) eccentricity forcing. Six large-scale sequences, 3–9 m in thickness, are recognized. Based on LAD and FAD of planktic foraminifers and the occurrence of two erosive surfaces related to major sea-level falls (Lang2/Ser1 and Ser4/Tor1), five Miocene sequences (Bu, L1, S1, S2, and S3) are correlated with third-order eustatic cycles.

KW - Burdigalian

KW - Cyclicity

KW - Heterozoan carbonates

KW - Lagos-Portimão Formation

KW - Langhian

KW - Open shelf

KW - Serravallian

KW - Warm-temperate waters

UR - http://www.scopus.com/inward/record.url?scp=85066251191&partnerID=8YFLogxK

U2 - 10.1007/s10347-019-0575-2

DO - 10.1007/s10347-019-0575-2

M3 - Article

VL - 65

JO - Facies

JF - Facies

SN - 0172-9179

IS - 3

M1 - 33

ER -