Details
| Original language | English |
|---|---|
| Article number | 105547 |
| Journal | Journal of African earth sciences |
| Volume | 224 |
| Early online date | 23 Jan 2025 |
| Publication status | E-pub ahead of print - 23 Jan 2025 |
Abstract
Reef communities changed dramatically during the Early Jurassic as they recovered from the End-Triassic Mass Extinction. The Atlas Rift Zone in Morocco provided expansive shallow water substrate, which allowed a variety of reef communities to develop, such as lithiotid bivalves that established themselves as new and prolific reef builders alongside corals, microbialites, and sponges in the Sinemurian and Pliensbachian stages. To better understand the dynamics between these reef builders and their environments, a detailed facies analysis of upper Pliensbachian reefs and a quantitative analysis of their composition was undertaken. We describe two distinct environmentally controlled reef types in the Central High Atlas Mountains. Lithiotid bivalves dominated reef construction in lagoonal environments and, together with phaceloid corals, commonly built bioherms and biostromes that ranged from 1 to 2 m tall and up to several hundred meters wide. Meanwhile, on the platform edge, microbialites, corals, and sponges constructed patch reefs up to 7 m tall and 20 m wide. These two reef types share common facies, as many of the same reef inhabitants, and some framework builders, grew in both environments. Despite the facies overlap, the communities in these two environmental settings are distinct, which is likely a result of environmental controls on the dominant reef framework builders. Moderately turbid waters and soft substrate in lagoons were ideal conditions for lithiotids but excluded many corals, sponges, and microbialites. Conversely, the clear, oligotrophic waters at the platform edge allowed photosynthetic and photosymbiotic organisms to thrive (e.g., coral and microbial reefs), while firmer substrate and higher wave energy may have prevented lithiotids from establishing dense populations.
Keywords
- Coral, Jurassic, Lithiotid, Microbialite, Microfacies, Pliensbachian, Reefs, Sponge
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)
- Geology
- Earth and Planetary Sciences(all)
- Earth-Surface Processes
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In: Journal of African earth sciences, Vol. 224, 105547, 04.2025.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Ecological differences in upper Pliensbachian (Early Jurassic) reef communities determined by environmental conditions in carbonate settings
AU - Stone, Travis
AU - Martindale, Rowan
AU - Bodin, Stéphane
AU - Lathuilière, Bernard
AU - Krencker, François Nicolas
AU - Fonville, Tanner
AU - Kabiri, Lahcen
N1 - Publisher Copyright: © 2025 Elsevier Ltd
PY - 2025/1/23
Y1 - 2025/1/23
N2 - Reef communities changed dramatically during the Early Jurassic as they recovered from the End-Triassic Mass Extinction. The Atlas Rift Zone in Morocco provided expansive shallow water substrate, which allowed a variety of reef communities to develop, such as lithiotid bivalves that established themselves as new and prolific reef builders alongside corals, microbialites, and sponges in the Sinemurian and Pliensbachian stages. To better understand the dynamics between these reef builders and their environments, a detailed facies analysis of upper Pliensbachian reefs and a quantitative analysis of their composition was undertaken. We describe two distinct environmentally controlled reef types in the Central High Atlas Mountains. Lithiotid bivalves dominated reef construction in lagoonal environments and, together with phaceloid corals, commonly built bioherms and biostromes that ranged from 1 to 2 m tall and up to several hundred meters wide. Meanwhile, on the platform edge, microbialites, corals, and sponges constructed patch reefs up to 7 m tall and 20 m wide. These two reef types share common facies, as many of the same reef inhabitants, and some framework builders, grew in both environments. Despite the facies overlap, the communities in these two environmental settings are distinct, which is likely a result of environmental controls on the dominant reef framework builders. Moderately turbid waters and soft substrate in lagoons were ideal conditions for lithiotids but excluded many corals, sponges, and microbialites. Conversely, the clear, oligotrophic waters at the platform edge allowed photosynthetic and photosymbiotic organisms to thrive (e.g., coral and microbial reefs), while firmer substrate and higher wave energy may have prevented lithiotids from establishing dense populations.
AB - Reef communities changed dramatically during the Early Jurassic as they recovered from the End-Triassic Mass Extinction. The Atlas Rift Zone in Morocco provided expansive shallow water substrate, which allowed a variety of reef communities to develop, such as lithiotid bivalves that established themselves as new and prolific reef builders alongside corals, microbialites, and sponges in the Sinemurian and Pliensbachian stages. To better understand the dynamics between these reef builders and their environments, a detailed facies analysis of upper Pliensbachian reefs and a quantitative analysis of their composition was undertaken. We describe two distinct environmentally controlled reef types in the Central High Atlas Mountains. Lithiotid bivalves dominated reef construction in lagoonal environments and, together with phaceloid corals, commonly built bioherms and biostromes that ranged from 1 to 2 m tall and up to several hundred meters wide. Meanwhile, on the platform edge, microbialites, corals, and sponges constructed patch reefs up to 7 m tall and 20 m wide. These two reef types share common facies, as many of the same reef inhabitants, and some framework builders, grew in both environments. Despite the facies overlap, the communities in these two environmental settings are distinct, which is likely a result of environmental controls on the dominant reef framework builders. Moderately turbid waters and soft substrate in lagoons were ideal conditions for lithiotids but excluded many corals, sponges, and microbialites. Conversely, the clear, oligotrophic waters at the platform edge allowed photosynthetic and photosymbiotic organisms to thrive (e.g., coral and microbial reefs), while firmer substrate and higher wave energy may have prevented lithiotids from establishing dense populations.
KW - Coral
KW - Jurassic
KW - Lithiotid
KW - Microbialite
KW - Microfacies
KW - Pliensbachian
KW - Reefs
KW - Sponge
UR - http://www.scopus.com/inward/record.url?scp=85216665901&partnerID=8YFLogxK
U2 - 10.1016/j.jafrearsci.2025.105547
DO - 10.1016/j.jafrearsci.2025.105547
M3 - Article
AN - SCOPUS:85216665901
VL - 224
JO - Journal of African earth sciences
JF - Journal of African earth sciences
SN - 1464-343X
M1 - 105547
ER -