Help|Log In|Register|
Home PageMindat NewsThe Mindat ManualHistory of MindatCopyright StatusManagement TeamContact UsAdvertise on Mindat
Donate to MindatSponsor a PageSponsored PagesTop Available PagesMindat AdvertisersAdvertise on Mindat
Minerals by PropertiesMinerals by ChemistryAdvanced Locality SearchRandom MineralSearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
StatisticsThe ElementsMember ListBooks & MagazinesMineral Shows & EventsThe Mindat DirectoryHow to Link to MindatDevice Settings
Photo SearchPhoto GalleriesNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day Gallery

Monumento Natural Bosques Petrificados, Deseado Department, Santa Cruz, Argentina

This page is currently not sponsored. Click here to sponsor this page.
Latitude & Longitude (WGS84): 47° 40' 0'' South , 68° 10' 3'' West
Latitude & Longitude (decimal): -47.66667,-68.16750
Köppen climate type:BSk : Cold semi-arid (steppe) climate

Petrified Forest Natural Monument.
Almost in the geographical center of the desert steppe of the Santa Cruz province, 150 km Puerto Deseado and 60 of the national route Nº 3, lies the petrified forest.
"Madre e Hija" (405 metres above sea level), with its two characteristic peaks, is the dominant elevation over the Valley of "Laguna Grande". There is the Petrified forest national monument with its fossil Araucarias. This peak is a volcano off and is responsible for the geological zone configuration and stands just 200 metres above the surface of the Valley, although it is not responsible for the cataclysm that produced the degree of las araucarias, that happened several million years before the birth of this volcano.
During the Jurassic of the Mesozoic era, 150 million years ago, this desert was an orchard, and the immense Araucaria Mirabilis and Para-Araucarias of more than 160 metres high and with some specimens that lived more than 1,000 years, gave shade and food to the dinosaurs of the region. Then, at the end of the Middle Jurassic, forests of Araucarias fell by terrible winds and were covered by the ashes of intense volcanic activity. Later, rainwater charged with sales of silicon to traverse that ash. These Silicon salts underwent the plant tissue of las Araucarias replacing it. The process by which the oxide of Silicon replaced plant cells of these trees, literally turning them into stone, was so gradual and complete that nothing was lost from the original structure of plant cells that, even today, can be identified easily in the laboratory. Perhaps the only thing that altered was its original color: reddish today by the presence of iron oxide. Most of the logs of the forest are prepared with the Cup to the East and the root to the West. Almost everyone is cut in slices or segments. The reason for the segmentation is not entirely clear. It may have been the same weight from the ashes, or the different geological movements. The truth is that all courts respond to the original structure of the trunks, i.e. they failed in the weaker party. Some of the fossils measured 35 meters long and 3 in diameter.
Currently it is prohibited to remove material from the Park to ensure their conservation.
The floor is a thick cushion of petrified Araucaria splinters and cones of Araucaria and fossilized Ammonites are.
Main mineralization: Wood Opal, Opal, Chalcedony, Jasper, Quartz, Agate, Manganese oxides, Iron oxides.

Mineral List

Mineral list contains entries from the region specified including sub-localities

7 valid minerals.

Regional Geology

This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.

Click on geological units on the map for more information. Click here to view full-screen map on

145 - 201.3 Ma

ID: 1383117
Jurassic volcanic rocks

Age: Jurassic (145 - 201.3 Ma)

Comments: May include hypabyssal intrusions.

Lithology: Volcanic rocks

Reference: Geological Survey of Canada. Generalized geological map of the world and linked databases. doi:10.4095/195142. Open File 2915d. [18]

Data and map coding provided by, used under Creative Commons Attribution 4.0 License

Localities in this Region


This page contains all mineral locality references listed on This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.


Raúl Jorge Tauber Larry (1970).

Mineral and/or Locality is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization.
Copyright © and the Hudson Institute of Mineralogy 1993-2017, except where stated. relies on the contributions of thousands of members and supporters.
Privacy Policy - Terms & Conditions - Contact Us Current server date and time: October 23, 2017 23:32:19 Page generated: October 17, 2017 00:36:23
Go to top of page