The Earth Story

River basins - commonly dominated by plant life today, but very different in Earth's Precambrian when there was no plant life at the surface to anchor rivers in place. This scientist is working on how the shape of river basins and floodplains in the plantless Precambrian differ from those seen today.

Snaking through the sky 

This panoramic photograph of the Milky Way was taken in Serpentine National Park. The falls are formed where water tumbles over the Darling Scarp, a major fault near the coast in Western Australia that separates ancient, Precambrian aged crust from younger rocks in the Perth Basin to the west.

Ancient Hills These peaks slipping above the clouds are the Nandi Hills, found about 40 kilometers west of the city of Bengaluru (Bangalore) in southern India. The view here is snapped on a cloudy day from the Western Ghat Mountains that run down India’s western coastline.

The Colorado Mineral Belt The area of Colorado, running from Denver and Boulder heading southwest, is a geologic puzzle. It is loaded with economic ore deposits, and has been a key mining target for nearly 2 centuries. Why all these ore deposits sit here is something of a geologic enigma, and in fact it has even left its mark on the state's map. Denver, Colorado sits very near the northeastern end of the line of mines and the Geological Society of America (GSA) even houses its headquarters nearby in Boulder, Colorado. Why does Colorado host enough mineral mines to redraw their map? The answer is the Colorado Mineral Belt.

The Geologists who characterize Australia and the history of that ancient continent as preserved in the rock record.

Kinneyia This is a particularly neat and common variety of trace fossil, thought to be a common remnant texture of the time before multicellular life arose. Biofilms or microbial mats are one of the main ways that single celled life forms grow on Earth. They can be found in all sorts of environments today, such as tidal flats, the ocean floor near hydrothermal vents, and near hot springs. They grow layer by layer, with single cells anchored together by polymers produced by the bacteria, archaea, algae, and fungi that make them up. They are some of the oldest fossils on Earth, with evidence of their presence going back at least 3 billion years and possibly longer in disputed samples.

The Black Canyon of the Gunnison river cuts down into some of the metamorphic rocks at the heart of the Colorado Plateau - a record of the assembly of the southwestern US. This video captures the views from the rim and the trip down to the river, and this previous post of mine goes through the geology of the site: https://tmblr.co/Zyv2Js29pPqSl

Deformed Dikes I have a long-running hypothesis that I’ve spoken of here before, and that is that every rock in Greenland is awesome. This sample is no different. This is a metamorphic rock, a gneiss, showing boudinage of a mafic dike. 

How do we see if the pieces fit? This is a core of sediment taken from the northeastern portion of Australia’s Northern Territory. This area is filled with sedimentary rocks that formed in the latter half of the Precambrian, starting sometime around 1.5 billion years ago. At the time, this section of the planet was a deep basin that was slowly filling with sediments, something like the Gulf of Mexico today.

Dales Gorge Formation These redbeds are found in Western Australia near the northwestern corner of that continent, in the Pilbara region near the iron mining community of Pannawonica. They are all part of the Dales Gorge formation, one of the major sources of iron for mining in Australia and one of the classic Banded Iron Formations associated with the rise of oxygen on the planet.

Songshan These incredible rocks make up what is known as Shuce Cliff, one small part of the Songshan or Mount Song complex in northern China. Found in China’s Henan Province, Songshan is a geological complex consisting of 5 summits and ridges, the highest of which reaches 1512 meters above sea level. The area is also filled with religious significance, including the presence of Taoist temples and the Buddhist Shaolin Temple where Zen Buddhism is believed to have been founded. The area is also a UNESCO global Geopark, recognizing its geological and historical contributions to the world.

Taum Sauk Mountain These photos come from Taum Sauk Mountain; found in the southeastern portion of the state of Missouri and reaching an elevation of 540 meters, this is the highest elevation in that state.

Pretty Grand Although this landscape may seem familiar to lovers of the U.S. National Park System, this is a site far from the canyonlands of the Colorado River. This is the Fish River Canyon, located in southern Namibia on the western coast of Africa. The Fish River is Namibia’s longest river. It originates in the northern part of the country, travels most of the country’s length, and takes a path with wide meanders as it enters Richtersveld National Park. The river meanders back and forth by several kilometers and wide meanders are common for rivers that form on nearly flat topography. Therefore, this canyon sits on a site of an ancient river that slowly wound its way over the surface until it locked itself in place.

Saint George Basin Out in the far north of Western Australia and only accessible by air or boat lies this beautiful blue harbour carved by the rising sea at the end of the last ice age out of the ancient rocks. The dark green areas are tidal flats filled with mangrove forests that are submerged by the twice daily high tides, while the rest of the bay is bounded by steep cliffs. At the lower right, the Prince Regent River joins the basin, and the whole area is part of a UNESCO Biosphere Preserve of the same name, now incorporated into a larger national park encompassing the whole Mitchell plateau.

Folded and warped These sedimentary rocks in the southern Australian outback date from the latest Precambrian, and were deposited some 540 million years ago in a basin, before being uplifted into a mountain range and eroded into soft hills. The region is known as the Adelaide Rift Complex (or to use an older, now mostly abandoned, vocabulary geosyncline) and flows from the flinders ranges, through the Fleurieu Peninsula (of wine growing terroir fame) southwards to Kangaroo Island.

Salt Casts These are tiny cubes of mud found in one of the rocks of the Belt sequence of modern-day Montana. These Precambrian aged rocks were deposited over a billion years ago as a rift opened along the coast of the continent Laurentia, which would eventually go on to make up the bulk of North America. That rifting created deep basins where sediments could accumulate, giving us the modern day Belt rocks.