Biotic producers of Carbonate sediments

What is a coelomate?

A cavity that is filled with a fluid that contains organs.

Sponges

• Most primitive animal

• Cells are organized into a multicellular body and held together by a gelatinous substance, no tissues or organs

• Fixosessile organisms

• Filter feeders on detritus or microscopic organisms

• produce toxins to avoid predation and protection

• main modern reef builders

What us the osculum of a sponge

• The central cavity of a sponge

Spicule

The hard skeleton of a sponge that is preserved in the rock record

• Can be siliceous or calcareous

Demosponge

• Skeleton mainly composed of spongin

Hyalosponge

• Skeleton mainly composed of spicules

Calcisponge

• skeleton composed of calcium carbonate

• Limited to shallow warm tropical areas

Ecological characteristics of sponges

• Can tolerate deep muddy water

Archaeocyatha

• Calcareous sponges with double walls from the Cambrian

• First skeletal reef builders

Stromatoporoids

• Calcareous skeleton

• Parallel lamellae

• Intersected pillar

• Most important reef builders in the late ordivician-devonian

Whya re sponges so important in carbonate sedimentology?

-Spicules are dominant deep water shelf to slope deposits

Bryozoans

• coelomates

• Colonial organisms

• Bilateral symmetry

• Lophophores

• Reproductive organs

• Circulatory and digestive system

What is a lophophore

Used for filter feeding by organisms

What kind of energy environments can bryozoans be found in?

• Branching bryozoans in low energy lagoons

• Fenestrate bryozoans in high energy reefs

Bryozoans in the environment

• Fixosessile, epifaunal and filter feeders

• Act to trap loose sediment forming skeletal pavement

• Reef builders,

• No photosynthetic component so can tolerate deep turbic water salt fluctuations and high levels of sediment

Why are bryozoans important in carbonate geology

• Common in all environments

• Form and shape tells us about the environment

• Important reef builders in paleozoic rocks

• Act as binders baffles and stabilizers

Brachiopod morphology

• Protostome

• Plane of symmetry perpendicular to hinge line

• Pedicle moves the brachipod around

• lopophore

Different Brachiopod life strategies

• Fixosessile

• Infaunal (burrowing)

• Librosessile (free lying)

Brachipod shell composition

• Carbonate

• multiple layers of sheet like calcite (foliated)

• These layers are at a gentle angle

Are molluscs or Brachiopods are dominant in modern day?

Molluscs, up to the outer slope

Why are brachiopods important in carbonate sedimentology

• Good biostratigraphic markers

• usually well preserved even in altered limestone and preserved the original chemical signature of the water

Protosome vs deuterosome

1. Protosome is mouth forms before the anus

2. Deuterddtome the anus forms before the mouth

Overview of Phylum Echinodermata

• Benthic (on the sea floor)

• Vagile (move on sea floor)

• Can swim against current

• From Cambrian to present day

• Invertebrates

What kind of echinoderms are carnivores?

Starfish

Ossicles

• Calcareous endoskeleton of echinoderms

• High Mg Calcite

Echinoder, fossils sediment relationship

• Crinoid grains for sediment

• Reef destroyer (when the bore into them)

Why are echinoderms important in carbonate geology?

• Major contributor of carbonate sedimentd

• Dont like hyper saline environments

• Indicative of storm deposits

• Open marine conditions

Coral Overview

• Cnidarians

• No organs

• Tissue level organiszation

Symbiotic relationship with cnidarians and zooxanthellates

• Dynophlagelates are friendly with cnidarians and allow corals to get quiet large in size

Cnidarian life cycle

• Polyp, asexually reproduce through budding and create haploid cells

• Medusa: adult free swimming, jellyfish shaped that reproduces sexually

Class Anthozoa is made up of:

• Zoantharia

• Tabulata

• Rugosa

• Scleractinia

Subclass Zoantharia

Sea anemones and true corals, solitary or colonial and are entirely marine

• Reef builders

Order Tabulata

Colonian Calcitic skeleton in the paleozic, permian extinction

Order Rugosa

Solitary or colonial, calcitic skeleton in the paleozoic (permian extinction)

• Abundance of diversity in silurian and devonian

• Paleozoic coral-stromatoporoid reef builders

Order Scleractinia

• SOlitary or colonial, aragonitic skeleton, modern day corals

• Solitary lives in deep water

• main modern day reef builders

• Fixosessile

Hermatypic vs ahermatypic corals

Hermatypic corals need to be in the photic zone

Ahermatypic corals dont need light

Why are corals important in carbonate geology

• Built large reefs in the phanerozoic

• Need light, no turbidity, little nutrients

• Significant sediment producers

Foraminifers

• Single Cell Eukaryotes

• Construct a test

• Most are marine,

• Present everywhere from equator to the poles

How are the single cell forams divided?

• Granular endoplasm

• Transparent Ectoplasm

WHat are pseudopods used for?

• Locomotion

• Anchoring

• Capturing food

What do symbionts allow to happen for marine life?

• More energy accumulation and therefore large size

Why are forams important in carbonate geology

• Major sediment producers (Caco3)

• Good paleoenvironmental indicators

• Individual species are happy in very specific environments

Calcareous algae overview

• Multicellular algae

• Photosynthetic autotrophs

• Calcified thalus

• Green Algae

• Red Algae

Green Algae

• tropical algae

• Most common in backreef and lagoonal setting (low energy)

• Shallow water

• Important carbonate sediment producers

Calcareous Red Algae

• Red algae is very good at absorbing light

• Can live in deep and cold water

• Coralline algae is the only modern algae around

Why is calcareous algae important for carbonate geology

• Major sediment producers (and micrite)

• Best paleoenvironment indicators

• Water depth, photic zone, low nutrients, low turbidity, Greatly affected by temperature

• Very important as reef builders, binders bafflers and framers

Arthropod overview

• Protosomes

• Most diverse animal phylum

• Underrepresented in rock record due to difficulty preserving

• Open circulatory system, blood moves through the body

• Exoskeleton

Trilobite

• 3 lobes

• Oldest animal with advanced eyes (compound eyes)

• Benthix, vagile and deposit feeders

• Like murkey deep water

• Cruziana trace fossil

WHy are Trilobites important in carbonate geology

• Went extinct at the permian

• Occupy all geological niches

• Not reef builders

• Warm and cool water

Ostracods

• Marine and fresh water

• Has 2 valves

Why are ostacods not important in carbonate geology

• Not abundant, lagoonal deposits

• cant tell environmental from thin section only

Molluscs overview

• Protosome

• Organs

• Bilateral organism

• Solitary

• Open circulatory system with heart

• Respiratory system

• Digestive system with radula (teeth)

• Nervous system with tentacles and eyes

• foot for locomotion

Bivalve

• Muscle foot for locomotion and burrowing

• Mantle secretes calcareous shell and forms siphons for filter feeding

• Gills used for filter feeding

• Symmetry is along hinge line

• mainly aragonite shells, so no external structure

What is Pectinid movement

• Bivalves that live ithin the water column expell water to move around

Name the 5 microphagy feeding strategies

Labial Palp deposit feeders

Epifaunal suspenion feeders

Infauanal non siphonate suspension feeders

Infaunal siphonate feeders

infaunal mucus tub feeders

Class Cephalopods

• Fast swimming through jet propulsion

• Advanced nervous system

• Shell devided into chambers with septa

• Only Nautoloids are around currently

4 different ammonitic suture patterns

• Ammonitic suture (most recent)

• Ceratitic suture (permian tri)

• GOniatitic (devonian Carbonif)

• Agoniatitic (oldest)

Belemnites class

• Thick guard of prismatic calcite

Gastropod class

• Large foot

• Torsion during development

• Entirely aragonitic (rarely preserved)

• Benthic

• Planktic

• Epiplanktic

• Nektic

• Land dwelling

Microphagy of Gastropods

• Herbivores

• Carnivores

• Detritus feeders

• Suspension feeders

WHy are molluscs important for carbonate geology

• Rudist bivalves built reef

• Gastropods and bivalves can produce a lot of pecal pellets

• Ammonites are good biostrat indicators