http://en.wikipedia.org/wiki/Mogollon-Datil_volcanic_field

Age of rock
Middle Tertiary




The calderas of the Boot Heel field include:

Pyramid Mountains - http://en.wikipedia.org/wiki/Pyramid_Mountains
Muir caldera 35.3 Ma
Peloncillo Mountains
Steins caldera 34.4 Ma
Animas Mountains
Juniper caldera 33.5 Ma
Animas Peak caldera 33.5 Ma
Tullous caldera 35.1 Ma
Chiricahua Mountains
Geronimo Trail caldera 32.7 Ma
Clanton Draw caldera 27.4 Ma
Portal caldera 27.6 Ma
Turkey Creek caldera 26.9 Ma
http://exploringaroundsantafe.blogspot.com/ boot heel nature

http://en.wikipedia.org/wiki/Boot_Heel_volcanic_field

http://volcano.oregonstate.edu/vwdocs/volc_images/north_america/arizona/navajo.html navajo volcanic field



the San Juan volcanic field in southwestern Colorado, the Trans-Pecos volcanic field in west Texas
Socorro-Magdalena caldera cluster The Chino (Santa Rita) and Tyrone mines near Silver City on the southwest side of the volcanic field plutons San Mateo Mountains volcano

Bursum caldera
The Mogollon-Datil volcanic field is a large silicic volcanic field in western New Mexico (Mogollon Mountains-Datil, New Mexico). It is a part of an extensive Eocene to Oligocene volcanic event which includes the San Juan volcanic field in southwestern Colorado, the Trans-Pecos volcanic field in west Texas and north central Mexico, the Boot Heel volcanic field in the bootheel of southwestern New Mexico and adjacent areas of Arizona and Mexico; and the vast volcanic field of the Sierra Madre Occidental of western Mexico. The Mogollon-Datil volcanic field was formed in "four discrete pulses representing synchronized activity of two separate cauldron complexes".The Socorro, New Mexico region (Socorro-Magdalena caldera cluster) of the central Rio Grande rift hosts an inflating mid-crustal sill-like magma body at a depth of 19 km that is responsible for anomalously high earthquake activity in the vicinity. Earth and space-based geodetic measurements indicate ongoing surface uplift above the Socorro Magma Body at approximately 2 mm/year The Datil Group, or series of volcanic and related formations (formerly the Datil Formation in New Mexico and eastern Arizona represents the extrusive output from the Mogollon-Datil volcanic field.Originally the Baca Formation was included in the group,[but now the group is considered to start with the Spears Formation. The base of the group, as originally defined, rests unconformably on the Mesaverde Formation, and the series is succeeded by the Popotosa Formation of the Santa Fe Group. The series consists of the following formations:
� Baca Formation, primarily fluvial red shales and sandstones of the Eocene, no longer considered part of the group;
� Spears Formation, latitic to andesitic conglomerates, mudflow deposits and thin, interbedded volcanic clastics and sandstones, followed by andesite flows interbedded with some conglomerates and mudflow deposits, approximately 37 Ma;
� Hells Mesa Tuff, over 680 m thick consisting of ash layers that erupted about 32.1 Ma, rhyolitic tuff with interbedded mudflow deposits and basalts;
� A-L Peak Tuff
� La Jara''''Peak Basaltic Andesite
Northern complex Socorro-Magdalena caldera cluster
Socorro Caldera - 32 Ma
Sawmill Canyon Caldera - 28.7 Ma
Hardy Ridge Caldera - 28 Ma
Mount Withington Caldera - 27.4 Ma
Bear Trap Caldera - 24.3 Ma

Mogollon-Datil volcanic field

Age of rock Middle Tertiary

Southern complex
Nogal Caldera - 28.4 Ma
Organ Caldera 32 Ma
Emory Caldera - 33 Ma
Twin Sisters Caldera - 31.4 Ma
Schoolhouse Mountain Caldera - 33.5 Ma
Mogollon Caldera (just one fragment in the Bursum Caldera wall) - 34.0 Ma
Bursum Caldera - 28.0 Ma
Gila Cliff Dwellings Caldera - 28.1 Ma

http://en.wikipedia.org/wiki/Datil-Mogollon_Section

The Datil-Mogollon Section is a physiographic section of the larger Colorado Plateaus province, which in turn is part of the larger Intermontane Plateaus physiographic division. It is a transitional area between the Basin and Range Province and the Colorado Plateau. It is also a newly defined unit that includes the southern part of the area previously designated the Datil Section.

Located along the southeastern rim of the Colorado Plateaus, in New Mexico and eastern Arizona is the Datil section. Most of the Datil section in Arizona is the White Mountain volcanic field. It is an extensive area covered with thick lavas and tuffs. There are also remnants of large stratovolcanoes, mainly composed of basaltic andesite. High tablelands are capped with tuffs, andesite, and basalt lavas, and volcanic-derived conglomeratic sandstones and mudstones. The principal structure of the area is a large central-type volcano called Mount Taylor that rises to 3,471 m, surrounded by numerous smaller volcanic centers and volcanic necks with extensive lava-covered mesas and valleys to the south. The largest mesa is 74 km long and about 37 km wide with an upper elevation of 580 m above the surrounding plain and is capped with about 91 m of lava. The ancient lava flows extend southward into the Mexican Highlands section of the Basin and Range Province and consequently that border of the Colorado Plateaus is ill-defined. Along the eastern edge of the Datil section, the Mexican Highlands section of the Basin and Range province extends northward along the Rio Grande depression to the Southern Rocky Mountains, and the boundary between the depression and the uplifted Colorado Plateaus is sharply defined by the western-most faults of the depression.It contains several large structural basins and block-faulted ranges. It is bounded on the east by basins of the Rio Grande rift, which are part of the Mexican Highland Section of the Basin and Range Provin


http://geoinfo.nmt.edu/tour/provinces/mogollon_datil_volcanic_field/home.html

Mogollon-Datil Volcanic Field

Lavas and tuffs erupted from andesitic to silicic volcanoes, domes, and calderas coalesced to form the Mogollon-Datil volcanic field in southwestern New Mexico between24 to 40 MA. This feature, which includes the mountainous terrain of the Gila Wilderness, covers 40,000 km2. First, andesite volcanoes erupted across this region 40 to 36 MA. Later, both basaltic andesite volcanoes and silicic calderas formed between 36 and 24 MA. The field is composed of two caldera complexes that were active at about the same time. The oldest eruptions of the southern complex occurred in the Organ Mountains near Las Cruces about 36 MA. Volcanic activity migrated from the Organ Mountains toward the northwest 220 km, ending with the eruption of the 28 MY Bursum caldera located northwest of Silver City. Caldera formation in the northern complex started near Socorro about 32 MA and migrated toward the southwest. The Mogollon-Datil volcanic field is part of a discontinuous belt of middle Cenozoic volcanism that runs from the Sierra Madre Oriental in central Mexico, through the Trans-Pecos volcanic field in west Texas, and northward to the San Juan volcanic field in southwestern Colorado. Extension began in this region about 36 MA, creating normal faults and distinct mountain blocks with intervening sediment -filled valleys. The extensional faults trend north-south on the east side of the field, northeast on the northwest side of the field, and northwest on the southwest side of the field. The Chino (Santa Rita) and Tyrone mines near Silver City on the southwest side of the volcanic field are in mineralized, older plutons that are 55-70 MY. The copper that was dispersed throughout the plutons was concentrated by weathering when these rocks were eroded and brought to the surface prior to the eruption of the younger 24 to 40 million year old volcanic rocks. The younger volcanic rocks covered the concentrated copper mineralization, protecting it from removal by erosion. Peaks of the Sawtooth Mountains near Pie Town, NM, rise above the surface in these southern reaches of the Colorado Plateau. The Sawtooths are part of the Mogollon-Datil Volcanic Field, and are the sedimentary deposition of pyroclastics weathered from the volcanic action between 24 and 40 MA. The sedimentary layers also include breccias composed of large pieces of the country rock at the time, limestones and sandstones that were incorporated by the streams that deposited the weathered volcanics. Looking southwest across the plains of San Augustin towards the San Mateo Mountains west of Magdalena. During the last ice age, a glacial lake resided within the downfaulted block between two upfaulted mountain ranges. The lake within this graben finally disappeared about 8,000 years ago. I was standing on an old beach bar of the lake that once was. The San Mateos are volcanic in nature, and the rock is composed of ash flow tuff and rhyolite flows that erupted during the Oligocene, about 28 MY.http://ragamuffinstudies.blogspot.com/2011/01/good-weather-for-road-trip.html http://whileoutriding.com/tag/san-mateo-mountains/


Picture
Figure 2. Map showing the Mogollon-Datil volcanic field of New Mexico with respect to other Cenozoic volcanic fields in Colorado, Texas, and New Mexico. MD= Mogollon-Datil, BH=Bootheel, TP=Trans=Pecos, SB = Sierra Blanca, SJ=San Juan,CC=Cripple Creek, J=Jemez. From Chapin et al. (2004).


The Chino (Santa Rita) and Tyrone mines near Silver City on the southwest side of the volcanic field plutons San Mateo Mountains volcano







http://ragamuffinstudies.blogspot.com/2011/01/good-weather-for-road-trip.html http://whileoutriding.com/tag/san-mateo-mountains/

A reconnaissance geochemical survey of stream drainages within 21,000 km2 of southeastern Arizona and southwestern NewMexico shows broad zones of low-level to moderate contrast anomalies, many associated with mid-Tertiary eruptive centers and Tertiary fault zones. Of these eruptive centers, few are known to contain metallic deposits, and most of those known are minor. This, however, may be more a function of shallow erosion level than an indication of the absence of mineralization, since hydrothermal alteration and Fe-Mn-oxide staining are widespread, and geochemical anomalies are pervasive over a larger part of the region than outcrop observations would predict. Accordingly, interpretations of the geochemical data use considerations of relative erosion levels, and inferred element zonalities, to focus on possible undiscovered deposits in the subsurface of base-, precious-, and rare-metal deposits of plutonic-volcanic association. In order to enhance the identification of specific deep targets, we use the empirically determined ratio:

This ratio is based on reported metal contents of nonmagnetic heavy-mineral samples from the drainage sediment, determined by emission spectrographic analysis. Before the ratio was computed for each sample site, the data were normalized to a previously estimated regional threshold value. A regional isopleth map was then prepared, using a cell-averaging computer routine, with contours drawn at the 25th - http://www.sciencedirect.com/science/article/pii/0375674289900861