Standstill Theory of Murray: On origin of Coral Reefs and Atolls

Imagine an underwater construction site where corals are the architects, and the ocean floor is their building foundation. Unlike Darwin, who believed reefs evolved due to land sinking (subsidence), John Murray (1880) proposed a completely different idea—the Standstill Theory, which argues that reefs grow only on stable submarine platforms with an unchanging sea level.

The Core Idea: Stability Over Subsidence

Murray’s theory rejects the idea that reefs form due to land subsidence. Instead, he states that corals need a stable, shallow underwater platform (not deeper than 180 feet or 30 fathoms) to grow.

Step-by-Step Formation of Coral Reefs

1. Stable Platform for Coral Growth
   • Corals do not grow on sinking land; instead, they thrive on stable underwater platforms.
   • If a platform is too shallow (<180 feet), it undergoes erosion by waves.
   • If a platform is too deep (>180 feet), sedimentation buries it, making it unsuitable for corals.
   • Only when the platform reaches an ideal depth (~180 feet) can corals start growing.
2. Fringing Reef Formation
   • Once conditions are right, coral polyps begin growing along the edges of the platform, forming a fringing reef attached to the coast.
3. Barrier Reef Formation
   • As corals continue growing, they build upon their own dead remains, gradually forming a barrier reef further away from the coast.
   • A lagoon appears between the land and the reef due to the dissolution of dead corals.
4. Atoll Formation
   • As corals grow outward, an atoll (a ring-shaped reef) can form.
   • The seaward side of the reef has active, living corals, which keep expanding.
   • The lagoon-ward side contains dead corals, which dissolve over time, making the lagoon shallower.

Key Differences from Darwin’s Subsidence Theory

Aspect	Darwin’s Subsidence Theory	Murray’s Standstill Theory
Land Movement	Land subsides (sinks)	Land remains stable
Coral Growth	Corals grow to keep up with subsidence	Corals grow only on stable platforms
Reef Evolution	Fringing → Barrier → Atoll due to sinking land	Fringing → Barrier → Atoll due to coral debris accumulation
Lagoon Formation	Forms due to land subsidence	Forms due to dissolution of dead corals

Criticism & Limitations of Murray’s Theory

While the Standstill Theory offers an alternative explanation, it has major flaws:

1. Requires Too Many Stable Platforms
   • Murray’s theory assumes that numerous flat submarine platforms exist exactly at 180 feet depth, which is highly improbable.
2. Contradictory Processes
   • He claims that erosion and deposition happen simultaneously on different submarine peaks, which is geologically unrealistic.
3. Rigid Depth Limit (30 Fathoms)
   • Murray states that corals cannot grow beyond 180 feet (30 fathoms), but modern research has found coral reefs at greater depths.

Final Thoughts

Murray’s Standstill Theory challenges Darwin’s subsidence-based explanation by arguing that coral reefs form only on stable seabeds. However, its over-reliance on ideal depth conditions and unrealistic assumptions make it less accepted in modern geology.

Ultimately, while both theories contributed valuable insights, today’s scientists recognize that coral reef formation is influenced by multiple factors, including subsidence, sea-level changes, sedimentation, and coral adaptation over time. 🌊🐠