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2013-01-10

Welcome to Laurasia, Gondwana

Feather Wilson

What was it like 360 million years ago?
There was nothing for humans to worry about. We were not even a glint in a deep fish's eye.
There was only one continent and its name was Gondwanaland. Glaciers drifted into middle South America. The United States was covered with low elevation swamps and shallow seas. Strange ferocious fish occupied many of the cratonic basins.
The cratonic basins that occupied North America were anoxic. That means the bottom of these connected inland seas lacked oxygen. Black richly organic mud accumulated on the bottom of the seas.
The only inland sea that is anoxic today is the Black Sea that is barely connected to the Mediterranean with a shallow lip at its neck called the Bosporus Straight.
Geologists call this Earth Period, the Devonian. The Devonian lasted from about 416 million years ago to about 360 million years before the present. A Devonian inland sea was present beneath Bandera County and its rock record is buried at about 10,000 feet in western Bandera County. It was an anoxic sea full of black organic mud.
This Devonian black organic mud is now the largest oil and gas producing unconventional shale play in North America found in multiple cratonic basins across ancient Gondwanaland or simply Gondwana.
Gondwana was a single continent. The North American portion of Gondwana was known as Laurasia. Bandera County was part of Laurasia.
The Eagle Ford that we read so much about in South Texas is not the largest shale producer. That is the Barnett in the Fort Worth Basin and the Bakken in the Williston Basin in North Dakota and Wyoming and part of Canada.
These Gondwana inland Devonian seas may prove to be the largest shale gas producing rocks, the world over.
The term "shale gas" is a misnomer. Shale gas basins produce oil, gas and a gasoline like condensate. All of these shales were previously considered source rocks and now they have morphed into reservoir rocks.


Weekly Rainfall = 0.00"
Cumulative Rainfall = 00.00"
Departure From Normal = -1.72"
Tarpley Glen Rose WL = 41.07'
Bandera Hosston WL = 435.10'
Hondo (USGS) Flow = 0.18 cfs
Williams Flow = 0.67 cfs
Medina (USGS) Flow = 12.00 cfs
Medina (USGS) Lake = -72.05'
High (F°) = 67°
Low (F°) = 23°
01-02-13 @ 8:00 am