Calderas and mineralization: volcanic geology and mineralization in the Chianti caldera complex, Trans-Pecos Texas

Duex, Timothy W.; Henry, Christopher D.

doi:10.2172/5305369

Cited by 3 publications

(2 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Calderas have long been recognized as hosts for hydrothermal systems that can be economically important for geothermal power and the localization of ore deposits (e.g., Smith and Bailey, 1968;Rytuba, 1976;Duex and Henry, 1981;Stelling et al, 2016). In addition, characterizing hydrothermal activity in large, modern calderas worldwide (e.g., Yellowstone, USA, Campi Flegrei, Italy, Taupo, New Zealand) has been important in understanding their restless behavior and associated hazards (Peltier et al, 2009;Rinaldi et al, 2010;Hurwitz and Lowenstern, 2014).…”

Section: Introductionmentioning

confidence: 99%

“…It is not well understood why some calderas host hydrothermal systems while others do not or what factors promote fluid localization in certain parts of a caldera. In particular, caldera "ring faults" are commonly suggested to be important structures for localizing fluid flow (e.g., Duex and Henry, 1981;Wood, 1994;Guillou-Frottier et al, 2000;Stix et al, 2003;Kissling and Weir, 2005); yet no studies to date have focused on a thorough examination of their permeability structure.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Controls on hydrothermal fluid flow in caldera-hosted settings: Evidence from Lake City caldera, USA

Garden¹,

Gravley²,

Kennedy³

et al. 2017

Geosphere

View full text Add to dashboard Cite

Silicic caldera volcanoes are often associated with hydrothermal systems economically important for electricity generation and localization of ore deposits. Despite their potential importance, the poor exposure that is typical in caldera settings has limited the number of detailed studies of the relationship between caldera structures and fluid flow. We use field mapping, outcrop scale scanline transects, and petrographic analyses to characterize fault rocks, alteration, and veins in the well-exposed 22.9 Ma Lake City caldera fossil hydrothermal system. The caldera margin consists of relatively straight segments linked by more structurally complex intersections; these structural intricacies produce a zone of deformation that can reach >300 m wide. Structural analyses show that the wide (up to ~60 m) fault core of the ring fault contains abundant subparallel veins, with orientations similar to that of the caldera margin. Smaller displacement faults inside the caldera generally have narrow (<1 m), hydrothermally cemented fault cores with more variably oriented veins in the surrounding damage zone. These findings at Lake City illustrate that fluid flow is controlled by lithology and the location and displacement of faults, e.g., ring fault versus intracaldera fault. Fault connectivity is another key control. We propose a conceptual model where fluid flow in caldera-hosted settings is influenced by: (1) the presence of favorable lithologies (proximity to magmatic intrusions and/or the presence of permeable lithologies), (2) a high density of faults and fractures, and (3) favorable orientations of faults and fractures that promote the formation of discontinuity intersections.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Controls on hydrothermal fluid flow in caldera-hosted settings: Evidence from Lake City caldera, USA

Garden¹,

Gravley²,

Kennedy³

et al. 2017

Geosphere

View full text Add to dashboard Cite

show abstract

Variations in Caldera Development in the Tertiary Volcanic Field of Trans‐Pecos Texas

Series

1984

Collected Reprint Series

View full text Add to dashboard Cite

Calderas, #-30 km in diameter, are the major igneous centers of Trans-Pecos Texas. Twelve calderas occur in two north-northwest-trending belts. Eight, including two in adjacent Chihuahua, occur in a western alkali-calcic belt. Four are in an eastern alkalic belt. Additional calderas are probably associated with two major ash-flow sheets in the eastern belt. Sources exist for all major tuffs of Trans-Pecos, other than these two, so additional calderas are unlikely. All calderas were formed between 38 and 28 Ma ago. The two calderas in Chihuahua were formed 30 and 28 Ma ago and show significant differences in composition and eruptive style from the earlier calderas. Calderas are underlain by individual magma chambers that were active for no more than about I Ma. The caldera cycle in Texas is highly variable. Minor volcanism commonly occurred before ash-flow tuff eruption and caldera collapse. Tumescence occurred in at most two calderas. Ash-flow eruption and collapse were simultaneous in all calderas, as shown by thick, intracaldera tuffs that are interbedded with breccias shed from caldera walls. Collapse occurred along discrete fracture systems in most of the western calderas but along hinge zones in the eastern calderas and at least part of the two young calderas in Chihuahua. Sedimentation within calderas was minor. Preresurgent volcanism ranged from minor to extensive and was best developed in the western calderas, all of which show some form of resurgence. No eastern calderas were resurgent. Resurgence is expressed in many ways in western calderas, but only a few fit the classic model. Ring-fracture volcanism was irregularly developed. Hydrothermal alteration and ore deposition were abundant and spatially and genetically related to calderas in the western alkali-calcic belt. Alteration and ore deposition were minor to nonexistent in the eastern alkalic belt. [Henry and McDowell, 1982], and only the two calderas in Chihuahua are younger than 32 Ma. Magmatism in Trans-Pecos, except for activity younger than about 25 Ma associated with Basin and Range extension [Henry et al., 1983], is related to subduction along a paleotrench that lay off western Mexico [Henry et al., 1982; McDowell and Henry, 1983]. Trans-Pecos is the easternmost manifestation of an eastward sweep of magmatism that began near the trench at least 100 Ma ago [Coney and Reynolds, 1977] and reached Texas about 40 Ma ago. During most of the period of caldera formation, the area was under east-northeast compression, a continuation of the stress field that existed during Late Cretaceous -early Tertiary Laramide folding [Price and Henry, 1984]. A transition to tension occurred between 32 and 30 Ma ago, before formation of the two young calderas in Chihuahua. Three goals of this report are to (1)identify the calderas of Trans-Pecos Texas, (2) describe their geology and development, and (3) develop a broader picture of caldera formation. Erosion has exposed complete sections through most calderas, including caldera-filling ash-flow tuffs and other volca...

show abstract

Variations in caldera development in the Tertiary volcanic field of Trans‐Pecos Texas

Henry¹,

Price²

1984

J. Geophys. Res.

View full text Add to dashboard Cite

Calderas, 4–30 km in diameter, are the major igneous centers of Trans‐Pecos Texas. Twelve calderas occur in two north‐northwest‐trending belts. Eight, including two in adjacent Chihuahua, occur in a western alkali‐calcic belt. Four are in an eastern alkalic belt. Additional calderas are probably associated with two major ash‐flow sheets in the eastern belt. Sources exist for all major tuffs of Trans‐Pecos, other than these two, so additional calderas are unlikely. All calderas were formed between 38 and 28 Ma ago. The two calderas in Chihuahua were formed 30 and 28 Ma ago and show significant differences in composition and eruptive style from the earlier calderas. Calderas are underlain by individual magma chambers that were active for no more than about 1 Ma. The caldera cycle in Texas is highly variable. Minor volcanism commonly occurred before ash‐flow tuff eruption and caldera collapse. Tumescence occurred in at most two calderas. Ash‐flow eruption and collapse were simultaneous in all calderas, as shown by thick, intracaldera tuffs that are interbedded with breccias shed from caldera walls. Collapse occurred along discrete fracture systems in most of the western calderas but along hinge zones in the eastern calderas and at least part of the two young calderas in Chihuahua. Sedimentation within calderas was minor. Preresurgent volcanism ranged from minor to extensive and was best developed in the western calderas, all of which show some form of resurgence. No eastern calderas were resurgent. Resurgence is expressed in many ways in western calderas, but only a few fit the classic model. Ring‐fracture volcanism was irregularly developed. Hydrothermal alteration and ore deposition were abundant and spatially and genetically related to calderas in the western alkali‐calcic belt. Alteration and ore deposition were minor to nonexistent in the eastern alkalic belt.

show abstract

Calderas and mineralization: volcanic geology and mineralization in the Chianti caldera complex, Trans-Pecos Texas

Abstract: •~®ll@J®If®g) ®IID@J ~fiiiD®IT®llO~®~fi®IID8 W®ll~®IIDfi~ @®®ll®@~ ®IID@J ~fiiiD®IT®llfi~®~ll@IID firm ~Iffi® ~IffifiiiD®~fi ~®ll@J®IT® ~@ITIID~ll®lZ~ ~If®IID~~~®~@~ ~®lZ®~ \ DI&TRIBUTiON OF THiS OOCUME~T IS utlLIMH£0, hG-W Bureau of Economic Geology t-~

Cited by 3 publications

References 1 publication

Controls on hydrothermal fluid flow in caldera-hosted settings: Evidence from Lake City caldera, USA

Controls on hydrothermal fluid flow in caldera-hosted settings: Evidence from Lake City caldera, USA

Variations in Caldera Development in the Tertiary Volcanic Field of Trans‐Pecos Texas

Variations in caldera development in the Tertiary volcanic field of Trans‐Pecos Texas

Contact Info

Product

Resources

About