A Time of Calm – Geologic Stability
Prior to the close approach of the moon, a look at life on Earth gives us a picture of a relatively stable world. There is a general principle of geography which says that given a lack of uplift, eventually through erosion, a landmass will level itself toward sea level. This peneplain model proposes that without an energy source fueling continental collision and uplift, erosion will reduce continents to flat erosional plains. This seems to be the predominant environment of the early pre-approach age. The Permian period was a primordial world of low energy with little tectonic activity and a relatively fixed set of continents. All the land was concentrated in one large continent known to us today as Pangaea. Tectonic activity seems to have been slowly running down; plate tectonics, as we now know it today, seemed to be ebbing. This was a time of great calm in Earth’s tumultuous history.
This pre-close approach world was one of broad flat plains with sluggish rivers and large coastal/estuary environments. During the Permian period, great forests and swamps, which were the standard environment of the preceding carboniferous period, evolved into a drier, more continental climate. Mountains were apparently few, lost either to erosion or isostatic equilibrium. This is the period from which much of our carbon based energy system comes; oil, gas and coal are all important deposits of the carboniferous period. Huge quantities of carbon rich organic material were retrieved from the atmosphere and placed into storage in the planetary crust.
The environment evolved fairly steadily over long epochs of time as single celled life evolved in the oceans.For billions of years simple life survived in Earth’s oceans, slowing becoming more complex. This time is known as the Proterozoic. Life, for some as yet unknown reason, burst into complex form during what is known as the Cambrian explosion. The Cambrian era, in which advanced life first evolved all the way up to the end of the Permian period, is known as the Paleozoic era. A general age of the Permian period is 290-251 million years ago. There were some relatively minor extinctions along the way with quick recoveries, meteorite impacts, continental movements, and glaciations, but life survived and even evolved. This pre-approach world was a relatively stable and primordial time.
The Permian Extinction
The cause of the great Permian extinction, which ended this primordial age, has remained an enduring mystery. The extinction represents the end of the ancient way of life on earth, called the great dying; it marks the end of the Permian period. The Triassic period, which followed the extinction, is the first period of the Mesozoic era. The Mesozoic ended this long period of evolution and initiated the “middle age” of life.
It is this era (the middle of three eras of life on Earth) that is synonymous with the age of the dinosaurs. The CALM puts forth that the Mesozoic was a transitional era, representing the time between the ancient pre-approach world and the modern post-approach seasonal world of the Cenozoic Era, in which we live today.
There are several features of the Permian extinction event which must be addressed by any hypothesis which hopes to solve the mystery of the great dying. The eruption of the Siberian traps is the feature most associated with the Permian/Triassic boundary. Though it is accepted that the tremendous outpouring of volcanic material which formed the Siberian traps must have played a significant role in the extinction, it is generally believed that their must be more to the story.
A unique feature of the Permian extinction is the devastation which occurred to the shallow water marine species. These surf zone creatures were particularly hard hit by the extinction event. Interestingly, however, fresh water species seem to have been little effected. One explanation for this anomaly is that the deep waters of the oceans during the Permian period lacked oxygen and that something caused the deep ocean waters to mix with the well oxygenated surface waters, essentially suffocating the surf zone creatures.
Another explanation is that one feature of a single continent like Pangea is that there would simply be less coastline thus less territory for surf zone species. The Permian boundary is also a time of high erosion both from the land and in the surf zone. This too is a partial explanation, but are these enough to explain the level of extinction experienced at the P/T boundary?
A peculiar feature of the Permian extinction is the long time of recovery. Life hung in the balance for nearly 5 million years before genuine recovery began. In fact, this time on Earth has been described as “toxic to life”. Could the proximity of the moon to the earth explain this toxicity?
A New Model
The Close Approach Lunar Model is a comprehensive model which assigns one cause, the close approach of the moon, to solve a myriad of problems associated with the mystery of the Permian extinction. The close approach of the moon to the earth at the Permian had three major impacts on the earth. First, solid body tidal heating, similar to that found today on Jupiter’s moon Io, would have caused the massive Siberian traps which dumped huge quantities of volcanic material onto the earth’s surface and gases into the earth’s atmosphere.
Second, the gravitational pull of the moon on the earth’s oceans would have had a couple major effects, which are seen at the P/T boundary. The tidal tug of a closer Moon would drive the mixing of the deeper anoxic layers of the ocean, which in turn contributed to the surf zone extinctions. In addition, the large tidal surges would replace the placid tidal zones which had existed on Earth since life first formed. This very high energy environment would make life extremely difficult, particularly for the attached and filter feeding forms of life in the surf zone. This ecosystem had previously faced the smaller tides of a more distant moon. The disruption of the shallow reefs through tidal action brought on by the now closer moon caused increased erosion of the shoreline and the deposit of associated sediments onto these near shore environments, a catastrophe not experienced before on such a global scale.
Finally, the most devastating thing may well have been that the earth’s upper atmosphere was partially stripped away, exposing life to the radiation of space. We have learned about the ozone hole over the Antarctic and its dire consequences. The impact of the ozone hole is miniscule compared to how a closer moon would affect Earth’s atmosphere. Such a proximity would create toxic radiation on a global scale. A potential recent finding which backs up this theory is that there is evidence of surface deposits of ice on the moon, which is thought impossible. Could these deposits be the remains of a tenuous atmosphere which the moon pulled from the earth?
Life on Earth came closest to being exterminated, or at least set back to the single cell age of the Proterozoic, at the Permian-Triassic boundary, with some 95% of shallow marine creatures and 90% of all species becoming extinct. The CALM proposes that this devastation was the direct result of a close approach of the moon.