Author: David Scott Ogley
Publisher:
ISBN:
Category : Calderas
Languages : en
Pages : 0
Book Description
The Chisos Mountains in the central part of Big Bend National Park are a deeply-eroded volcanic-intrusive complex of Oligocene age. Intrusive and extrusive units of the complex are subalkaline to midly peralkaline, and belong to the Trans-Pecos magmatic province, forming the southernmost expression of that province in the United States. At least two calderas are present in the Chisos Complex, both of which were active during the mid-Oligocene. The younger of the two known calderas, the Pine Canyon Caldera, was the source vent for the four major ash-flow units of the South Rim Formation. Volcanic and sedimentary rocks of the Chisos Formation, which unconformably underlies the South Rim Formation, were deformed by pre-eruption inflation of the Pine Canyon magma chamber. During eruption of the lower members of the South Rim Formation, the caldera collapsed by sagging rather than by faulting. Eruption of the youngest member of the South Rim Formation was accompanied by ring fracturing and fault-controlled collapse. Whole-rock major-element chemistry demonstrates a petrogenetic relationship between the intrusive and extrusive members of the caldera complex. The volcanic members were derived by progressive tapping of a shallow magma chamber in which alkali feldspar and later quartz were fractionating. Compositions of successive members of the eruptive sequence project progressively closer toward the minimum in the system albite - orthoclase - quartz at 500 bars water pressure. A late ring dike is cumulus material from the magma chamber; its composition plots slightly more quartz-rich than the temperature minimum. The distribution of the South Rim Formation and the related intrusions can be explained by a multi-stage eruptive history. Two similar ash-flow cycles are represented by the four members of the South Rim Formation. All four members spread southwest from the caldera, and their distribution was restricted by topography of the caldera rim and the volcanic flank. Caldera collapse at the end of ash-flow activity resulted in uneven subsidence and allowed emplacement of the ring dike. Intrusion of granitic bodies west of the caldera, framing The Basin on the north and west, was the final stage of igneous activity
Eruptive History of the Pine Canyon Caldera, Big Bend National Park, Texas
Author: David Scott Ogley
Publisher:
ISBN:
Category : Calderas
Languages : en
Pages : 0
Book Description
The Chisos Mountains in the central part of Big Bend National Park are a deeply-eroded volcanic-intrusive complex of Oligocene age. Intrusive and extrusive units of the complex are subalkaline to midly peralkaline, and belong to the Trans-Pecos magmatic province, forming the southernmost expression of that province in the United States. At least two calderas are present in the Chisos Complex, both of which were active during the mid-Oligocene. The younger of the two known calderas, the Pine Canyon Caldera, was the source vent for the four major ash-flow units of the South Rim Formation. Volcanic and sedimentary rocks of the Chisos Formation, which unconformably underlies the South Rim Formation, were deformed by pre-eruption inflation of the Pine Canyon magma chamber. During eruption of the lower members of the South Rim Formation, the caldera collapsed by sagging rather than by faulting. Eruption of the youngest member of the South Rim Formation was accompanied by ring fracturing and fault-controlled collapse. Whole-rock major-element chemistry demonstrates a petrogenetic relationship between the intrusive and extrusive members of the caldera complex. The volcanic members were derived by progressive tapping of a shallow magma chamber in which alkali feldspar and later quartz were fractionating. Compositions of successive members of the eruptive sequence project progressively closer toward the minimum in the system albite - orthoclase - quartz at 500 bars water pressure. A late ring dike is cumulus material from the magma chamber; its composition plots slightly more quartz-rich than the temperature minimum. The distribution of the South Rim Formation and the related intrusions can be explained by a multi-stage eruptive history. Two similar ash-flow cycles are represented by the four members of the South Rim Formation. All four members spread southwest from the caldera, and their distribution was restricted by topography of the caldera rim and the volcanic flank. Caldera collapse at the end of ash-flow activity resulted in uneven subsidence and allowed emplacement of the ring dike. Intrusion of granitic bodies west of the caldera, framing The Basin on the north and west, was the final stage of igneous activity
Publisher:
ISBN:
Category : Calderas
Languages : en
Pages : 0
Book Description
The Chisos Mountains in the central part of Big Bend National Park are a deeply-eroded volcanic-intrusive complex of Oligocene age. Intrusive and extrusive units of the complex are subalkaline to midly peralkaline, and belong to the Trans-Pecos magmatic province, forming the southernmost expression of that province in the United States. At least two calderas are present in the Chisos Complex, both of which were active during the mid-Oligocene. The younger of the two known calderas, the Pine Canyon Caldera, was the source vent for the four major ash-flow units of the South Rim Formation. Volcanic and sedimentary rocks of the Chisos Formation, which unconformably underlies the South Rim Formation, were deformed by pre-eruption inflation of the Pine Canyon magma chamber. During eruption of the lower members of the South Rim Formation, the caldera collapsed by sagging rather than by faulting. Eruption of the youngest member of the South Rim Formation was accompanied by ring fracturing and fault-controlled collapse. Whole-rock major-element chemistry demonstrates a petrogenetic relationship between the intrusive and extrusive members of the caldera complex. The volcanic members were derived by progressive tapping of a shallow magma chamber in which alkali feldspar and later quartz were fractionating. Compositions of successive members of the eruptive sequence project progressively closer toward the minimum in the system albite - orthoclase - quartz at 500 bars water pressure. A late ring dike is cumulus material from the magma chamber; its composition plots slightly more quartz-rich than the temperature minimum. The distribution of the South Rim Formation and the related intrusions can be explained by a multi-stage eruptive history. Two similar ash-flow cycles are represented by the four members of the South Rim Formation. All four members spread southwest from the caldera, and their distribution was restricted by topography of the caldera rim and the volcanic flank. Caldera collapse at the end of ash-flow activity resulted in uneven subsidence and allowed emplacement of the ring dike. Intrusion of granitic bodies west of the caldera, framing The Basin on the north and west, was the final stage of igneous activity
Interpretation of Geophysical Anomalies Over the Pine Canyon Caldera, Big Bend National Park, Texas
Author: Benjamin John Drenth
Publisher:
ISBN:
Category : Calderas
Languages : en
Pages :
Book Description
Publisher:
ISBN:
Category : Calderas
Languages : en
Pages :
Book Description
Big Bend National Park Biosphere Reserve: Bibliography
Author: John A. Bissonette
Publisher:
ISBN:
Category : Big Bend National Park (Tex.)
Languages : en
Pages : 886
Book Description
Publisher:
ISBN:
Category : Big Bend National Park (Tex.)
Languages : en
Pages : 886
Book Description
Cenozoic Geology of the Trans-Pecos Volcanic Field of Texas
Author:
Publisher:
ISBN:
Category : Geology
Languages : en
Pages : 208
Book Description
Publisher:
ISBN:
Category : Geology
Languages : en
Pages : 208
Book Description
Oligocene Volcanism and Multiple Caldera Formation in the Chinati Mountains, Presidio County, Texas
Author: Joseph C. Cepeda
Publisher:
ISBN:
Category : Calderas
Languages : en
Pages : 40
Book Description
Publisher:
ISBN:
Category : Calderas
Languages : en
Pages : 40
Book Description
Igneous Geology of Trans-Pecos Texas
Author:
Publisher:
ISBN:
Category : Geology
Languages : en
Pages : 372
Book Description
Publisher:
ISBN:
Category : Geology
Languages : en
Pages : 372
Book Description
Report of Investigations
Author:
Publisher:
ISBN:
Category : Geology, Economic
Languages : en
Pages : 412
Book Description
Publisher:
ISBN:
Category : Geology, Economic
Languages : en
Pages : 412
Book Description
South-Central Section of the Geological Society of America
Author: O.T. Hayward
Publisher: Geological Society of America
ISBN: 0813754046
Category : Science
Languages : en
Pages : 482
Book Description
Publisher: Geological Society of America
ISBN: 0813754046
Category : Science
Languages : en
Pages : 482
Book Description
Guidebook
Author: University of Texas at Austin. Bureau of Economic Geology
Publisher:
ISBN:
Category : Geology, Economic
Languages : en
Pages : 84
Book Description
Publisher:
ISBN:
Category : Geology, Economic
Languages : en
Pages : 84
Book Description
Compilation of Potassium-argon Ages of Tertiary Igneous Rocks, Trans-Pecos Texas
Author:
Publisher:
ISBN:
Category : Geology
Languages : en
Pages : 40
Book Description
Publisher:
ISBN:
Category : Geology
Languages : en
Pages : 40
Book Description