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ROCKS, MINERALS & FOSSILS

New Mexico is ranked as follows:

  • third in the nation in natural gas production (1.70 trillion cubic feet) and second in reserves
  • seventh in oil (71.6 million barrels)
  • thirteenth in coal (24.6 million tons)
  • first in potash (1.27 million tons)
  • first in zeolite and perlite (approximately 500,000 tons)
  • third in copper (564 million pounds)
  • second in carbon dioxide (145.8 billion cubic feet)

(from New Mexico Bureau of Mines & Mineral Resources). This high degree of mineralization provides rock hounds with a large array of rocks and minerals to observe and collect.

ROCKS

A rock is, in general, an aggregate of minerals.  Some rocks consist of a single mineral such as limestone.  All three types of rocks can be found in Eddy County as follows:

Rock Type Location Examples
Igneous Guadalupe Mountains Basalt, Granite, Lava
Metamorphic Guadalupe Mountains Gneiss, Marble, Schist, Slate
Sedimentary The Ranch Plain
Capitan Reef
Shale, Sandstone, Conglomerate, Limestone

Igneous rocks are formed from a molten state after cooling and solidification.  Rocks that do not melt but become heated and the crystalline structure of these rocks change are called Metamorphic rocks.  These types of rocks are generally formed in mountain uplift areas.

Sedimentary rocks are formed at low temperatures and pressures at or near the earth’s surface by transportation, deposition, and eventual accretion of grains of material originally eroded from previously existing rocks, or as a result of precipitation of minerals from water.  Virtually all fossils are found in sedimentary rocks.

MINERALS

In general, a mineral is a homogeneous, naturally occurring inorganic solid.  The chemical composition of minerals vary only slightly and they have a characteristic crystal structure.  Over 2500 minerals have been described.  They are generally recognized by distinctive characteristics such as crystalline structure, hardness, and cleavage.  

The hardness scale used by geologist is called the Mohs' Scale.  It matches various minerals as follows:

Hardness Mineral Characteristic Scratch
1 Talc
2 Gypsum Fingernail (2.5)
3 Calcite Penny
4 Fluorite
5 Apatite
6 Orthoclase Feldspar Knife Blade or Window Glass
7 Quartz Hardened Steel File
8 Topaz Emery Cloth
9 Corundum
10 Diamond

Some minerals that can be found near The Ranch include the following:

Mineral Location Hardness Crystal Structure
Apatite Black River Village 5 Orthorhombic
Gold Bonito Lake near Ruidoso 2.5-3 Isometric, Octahedral, Dodecahedral, and Cubic
Gypsum Hills East of The Ranch 1.5-2 Monoclinic, Rhombic and sometimes Twinned
Pyrite Guadalupe Mountains 6-6.5 Isometric, primarily Cubic, less common Octahedron
Serpentine White City 3-5 Monoclinic, Fibrous, Lamellar and Columnar
Quartz Hills to East of The Ranch as Pecos Diamonds 7 Hexagonal, frequently terminated by double Rhombohedron

This is not an exhaustive list by any means.  The igneous and metamorphic rocks of the mountains to the west of The Ranch offer a wonderful opportunity to find beautiful crystals of quite a number of minerals.

Click on the small thumbnail photographs below to enlarge the image.  Use your back button to return to this page.  All are from New Mexico with the exception of the Calcite crystal (Mexico).

azurite_tourmaline.jpg (19762 bytes)
Azurite - Tourmaline
barite.jpg (5465 bytes)
Barite
calcite.jpg (6908 bytes)
Calcite
cerussite_galena.jpg (9923 bytes)
Cerussite - Galena
chalcopyrite.jpg (6287 bytes)
Chalcopyrite
native_copper.jpg (26212 bytes)
Copper - Native
fluorite_barite.jpg (16379 bytes)
Fluorite - Barite
fluorite_quartz.jpg (25175 bytes)
Fluorite - Quartz
gypsum_selenite.jpg (11991 bytes)
Gypsum - Selenite
halite1.jpg (8031 bytes)
Halite
halite2.jpg (12376 bytes)
Halite
linarite.jpg (18783 bytes)
Linarite
malachite_azurite2.jpg (19977 bytes)
Malachite - Azurite
quartz_specular.jpg (6063 bytes)
Quartz, Specular
quartz_black.jpg (8259 bytes)
Quartz, Smoky
sphalerite.jpg (10881 bytes)
Sphalerite

FOSSILS

Fossils are generally found in Sedimentary Rocks.  The Ranch is located on a sedimentary plain of alluvial origin (deposit of sand or mud formed by flowing water) but very few fossils will be found therein.  The hills in the distance; however, provide a wealth of fossils for much of it was a part of the large Capitan Reef.  Fossils that can be found in these rocks include the following:

Phylum Group Illustration
Coelenterata Corals  
Brachiopoda Brachiopods  
Mollusca Pelecypods
Mollusca Gastropods  
Mollusca Ammonites  
Echinodermata Crinoids
Calyx


Stem

Echinodermata Echinoids  
Arthropoda Triobites  

 

GEOLOGY / PHYSIOGRAPHY

New Mexico is located on the eastern edge of a tectogenic region (mountain-building) that became active during mid-Cenozoic time in a series of events known as the Laramide Revolution.  The western two-thirds of the state has been profoundly affected by these forces in the form of block faulting, vulcanism, and regional uplift, while the eastern third where The Ranch is a relatively level surface composed of sedimentary by-products of western diastrophism.  The Rio Grande Valley divides the region into eastern and western sections.  Western New Mexico is a land of mountains, mesas, plateaus, and intervening basins and valleys while Eastern New Mexico is a region of relatively level plains.  

The Ranch is located in Eastern New Mexico on a recently developed alluvial plain (Holocene - see Geological Time Scale below).  The hills to the south and east of The Ranch are composed of formations from the Permian period when the area was covered by a coral reef at the edge of a quiet, shallow sea in what is termed The Delaware Basin.  Coal deposits along with much of the oil and gas produced in the area originated in the rocks of this period and the other periods of the Paleozoic era.  At the end of the Paleozoic era, the sea receded and a large inland sea was formed in west Texas and our portion of southeastern New Mexico.  As the sea(s) dried, the evaporating water left wide-spread deposits of salty, gypsum-rich Permian Basin deposits.  These deposits to the east of Carlsbad are rich in potash that is now mined extensively for use in fertilizers.  Potash mines in this area are from 900 to 1800 ft underground.

Near The Ranch, oil and gas are produced from the underlying Permian limestone.  The wells with dinosaur pumps are oil wells while those with stacks of valves and gauges known as Christmas Trees are generally gas wells. The porous Permian rocks also carries water from the Sacramento Mountains about 60 miles west.  The nearby town of Artesia got its name from the artesian springs that emanate from these rocks. 

Guadalupe Ridge to the southwest of The Ranch is in reality an ancient coral reef known as the Capitan Reef for the peak at the end of the mountains.  Fossils abound in this reef including crinoids, brachiopods, corals, bryozoans, and gastropods.  The Sitting Bull Falls day-trip suggested below takes you to parts of this reef where you can observe the remains of these animals.

Geological Time Scale

ERA

PERIOD

EPOCH

SOUTHEAST NEW MEXICO

MILLION YEARS AGO

Cenozoic

Quaternary

Holocene

 

11,000 years-recent

 

 

Pleistocene

 

1.8 - 11,000 years

 

Tertiary

Pliocene

 

5-1.8

 

 

Miocene

 

23-5

 

 

Oligocene

 

38-23

 

 

Eocene

 

54-38

 

 

Paleocene

 

65-54

Mesozoic

Cretaceous

 

 

146-65

 

Jurassic

 

 

208-146

 

Triassic

 

 

245-208

Paleozoic

Permian

Ochoan

Dewey Lake

286-245

 

 

 

Rustler

 

 

 

 

Salado

 

 

 

 

Castile

 

 

 

Guadalupian

Tansill

 

 

 

 

Yates

 

 

 

 

Seven Rivers

 

 

 

 

Queen

 

 

 

 

Grayburg

 

 

 

 

San Andres

 

 

 

Leonardian

 

 

Pennsylvanian

 

 

325-286

 

Mississippian

 

 

360-325

 

Devonian

 

 

410-360

 

Silurian

 

 

440-410

 

Ordovician

 

 

505-440

 

Cambian

 

 

544-505

Pre-Cambrian

 

 

 

4500-544

 

Surface formations in the vicinity of The Ranch.
See color key on the Geological Time Scale above.
Adapted from Peter A. Scholle, 1980 and 1992.

SUGGESTED GEOLOGICAL DAY TRIPS

The Bureau of Land Management allows the removal of 250 lbs of rock or 25 lbs of minerals/crystals.  We are not allowed to dig for rocks or crystals.  

Each of the following field trips are available in black type with a white background and without photographs to facilitate printing and use as a log while traveling in your vehicle.  Click on the Trip Number to bring up this version of the log.

Pecos diamonds

TRIP 1. Chalk Bluff Road - Pecos Diamonds, well formed double-ended quartz crystals, abound along the Pecos River in the weathered Permian rocks.  They are particularly abundant on the slopes of the hills forming the horizon east of The Ranch, just across the Pecos River.  You can reach the collecting area as follows:

Mile Location Action/Observation
0.0 Ranch House
0.3 Main Gate Turn Right
1.6 Hwy 285 Turn Right
15.7 Hwy 82 in Artesia Turn Right
20.9 Chalk Bluff Road (Across Pecos River) Turn Right
21.5 First Cattle Guard
22.2 Second Cattle Guard
22.5 Third Cattle Guard
24.5 Fourth Cattle Guard
24.7 Small Wash Area on Right near Oil Pump Stop

Pecos Diamond Site

Pecos Diamonds collecting site.

Further along the ridge of these hills, you can find other good collecting sites in the Permian limestone rock.  When you get to a good collecting site, there should be a lot of glistening crystals on the ground resembling an area of broken glass.  We have particularly good luck collecting in wash (drain) areas.  A geologist at the Bureau of Land Management in Carlsbad told us of a collecting site on private land that has yielded crystals of several inches in length and diameter!  

Crystals in Matrix

Pecos Diamonds in matrix rock.

Scattered Crystals

Pecos Diamonds scattered on ground.

TRIP 2.  Sitting Bull Falls - The following field trip is based for the most part on a field log presented by Peter A. Scholle entitled Dark Canyon-SittingBull Falls-Rocky Arroyo contained in his work An Introduction and Virtual Geologic Field Trip to the Permian Reef Complex, Guadalupe and Delaware Mountains - New Mexico and West Texas.   

 

 

 

SUGGESTED LINKS AND REFERENCES

References

Chronic, H. 1987.  Roadside Geology of New Mexico.  Mountain Press Publ. Co., Missoula, Montana. 

Crow, M.  1995.  The Rockhound’s Guide to New Mexico.  Falcon Press Publ. Co., Helena, Montana.

Kimbler, F. S. and R. J. Narsavage Jr. 1981.  New Mexico Rocks & Minerals.  Sunstone Press, Santa Fe, New Mexico.

Kues, B.S. 1982.  Fossils of New Mexico.  Univ. New Mexico Press, Albuquerque, New Mexico.

Mitchell, J. R. 1987.  Gem Trails of New Mexico.  Gem Guides Book Co., Pico Rivera, California.

Links

New Mexico Bureau of Mines & Mineral Resources

An Introduction and Virtual Geologic Field Trip to the Permian Reef Complex, Guadalupe and Delaware Mountains, New Mexico-West Texas

The New Mexico Museum of Natural History and Science

 

 

THE RANCH
SKP Co-op Retreat of New Mexico, Inc.
P.O. Box 109
Lakewood, New Mexico 88254
Phone 505-457-2303 & FAX 505-457-2100
email:
skpranch@pvtnetworks.net

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