Geology of Blue Beach

History of Blue Beach

The cliffs and shoreline of Blue Beach expose beautifully bedded layers of sedimentary rocks. These consist mostly of sandstones, siltstones, and shales, which were laid down as sand, silt, and mud by rivers, lagoons, and along the ancient shores of a large marine bay or estuary, in brackish- (partially salty) to fresh-water conditions. The nearby landscapes were carpeted in dense, early forests and there were numerous swamps in the area. Primeval streams kept the landscape and the shoreline supplied with abundant sand and silt.

The main body of water in the former region filled a large depression of the Earth’s crust, known as the Maritimes Basin, which had formed at least 370 Million years (mya) ago. The depression was the result of a slow collision of continents, when what we today call Africa began to collide with Nova Scotia. This was the beginning of the formation of the supercontinent called ‘Pangea’.

Like all good sedimentary basins, the Maritimes Basin provided an ideal place for eroding sediments from nearby mountains that were thrust up by continental collision to collect, and for trackways to be buried and bones to accumulate.

The Maritimes Basin continued to gather sediments for over 70-million years. There are no sediments known from about the first 10-million years of the basin’s evolution. The Horton Group, represented best by the type-section at Blue Beach, are the oldest or lowest sediments found in the bottom of the basin, with an Early Carboniferous age of about 350 mya. Following the Horton Group come several later periods of sedimentation, each represented by differently-named rock groups, ultimately leading to the Upper Carboniferous rocks of Joggins and Sydney Mines in Nova Scotia. The incredibly complete succession of Carboniferous rocks seen in Nova Scotia has no parallel anyplace else on Earth.

Today, the sedimentary strata at Blue Beach have been slightly tilted from the horizontal and lifted into view. The entire section of rocks exposed in the 4 km of cliffs have suffered neither serious folding nor faulting, so their fossil contents have suffered virtually no distortion or damage. Other Horton Group exposures of rock contain nothing like the kind of fossil variety or density seen at the Blue Beach locality. Indeed, few other exposures yield more than plants or invertebrates.

The first scientists to study the rocks at Blue Beach arrived in the early 1800’s. The first investigators included the team of Jackson and Alger (1828) who developed the first Geological map of Nova Scotia, and then Abraham Gesner (1836), the man who invented kerosene. These Geologists were not able to reach a consensus on the age of the rocks.

Sir. W. E. Logan, could not resist an opportunity to investigate new geological outcrops during his early travels. In late 1841 it was Blue Beach (then called Horton Bluff) that caught his attention, and little did he expect the surprise that awaited him…

It was Sir. W. E. Logan, for whom the highest peak in the Canadian Rockies is named, who discovered the tetrapod footprints at Blue Beach. Those footprints made Blue Beach the classic fossil locality that it remains today. They were the first evidence ever uncovered to indicate the existence of Carboniferous amphibians. Logan's find marks the official birth of vertebrate paleontology in Canada, predating the finds at Joggins by more than a decade.

Logan discovers the clear impressions of footprints on a slab of finely-glazed sandstone. This was not only “the dawn of vertebrate palaeontology in Canada”, but the first time scientists anywhere realized land-animals began as early as the Carboniferous Period.

Logan was followed in the year 1842 by a visit from the father of modern geology himself, Sir Charles Lyell, who came to try and settle the age-debate for the Blue Beach and other Bay of Fundy Carboniferous exposures. Lyell’s opinion mirrored that of Logan , that these rocks were very early in the Carboniferous series.

Blue Beach went on to be described by Sir John William Dawson, the first Canadian born scientist to achieve international recognition, in his landmark work, “Acadian Geology” in 1868. In it he described a few of the fish remains, invertebrates, plants and traces that provided the first detailed summary of the site. Few studies followed Dawson's work, and besides the appearance of the occasional papers from 1903 to 1933 which revise the description of Logan’s track find, nothing new was reported until the 1970’s.

A brief flurry of interest again at Blue Beach resulted from the discovery of the first tetrapod bones in 1967 by Donald Baird of Princeton University. Field teams from several major institutions begin to visit the area yearly in hopes of gathering more, but the sparse bones of tetrapods accumulate very grudgingly, and in the year 2000 it was reported that the locality of Blue Beach would “probably never yield more than a few tantalizing glimpses” (of the tetrapods).

However, undaunted by these reports, the BBFM project began in 1995, and within a few years had achieved far more than the other scientists had ever seen within its collections. Today, with over 35 tons of fossil material, the BBFM has ensured that researchers have enough bones and traces to renew their interest on every level. International researchers come to Blue Beach every year to investigate the outcrops and the unparalleled collection of the BBFM.

 

Blue Beach is recognized as the worlds’ most-important Lower Carboniferous fossil locality. Acknowledged for providing the oldest-known terrestrial vertebrates, (bones and tracks), along with fishes, plants, and more in well-preserved abundance – it is a true fossil LAGERSTATTE (“motherlode”).