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![Simplified geologic map of the Jackass Lakes pluton and host rocks and location of detailed mapping of Sing Peak pendant (see Fig. 3), modified from Peck (1980).]()
![(A) Map of Jackass Lakes pluton after Pignotta et al. (2010). See Figure 1 for location. Note large pendants and smaller blocks in the Jackass Lakes pluton. UTM—Universal Transverse Mercator coordinates. (B) Grid map of metavolcanic block formation in Jackass Lakes granodiorite showing vein and dike growth and multiple intrusions into dikes along block margins. JLP—Jackass Lakes pluton. (C) Photo of metavolcanic block in Jackass Lakes pluton with magmatic layering along block margins. Hammer is ∼30 cm long. (D) Highlighting of C showing metavolcanic block (green), leucocratic granitic material along block margin (orange), and two sets of magmatic layering that formed along block margins (dashed and dotted black lines). Some erosion of older layers and crosscutting relationships indicate that dotted layers formed first, then the dashed. Both sets of magmatic layering contain pieces of partially melted(?) metavolcanic block material forming diffuse metavolcanic fragments. Graded magmatic layers form where more mafic material accumulated at the bottom of the layer. Magmatic foliation crosscuts all structure (lithologic contacts, magmatic layering) and strikes approximately north-south in photo.]()
![(A) Map of Jackass Lakes pluton after Pignotta et al. (2010). See Figure 1 for location. Note large pendants and smaller blocks in the Jackass Lakes pluton. UTM—Universal Transverse Mercator coordinates. (B) Grid map of metavolcanic block formation in Jackass Lakes granodiorite showing vein and dike growth and multiple intrusions into dikes along block margins. JLP—Jackass Lakes pluton. (C) Photo of metavolcanic block in Jackass Lakes pluton with magmatic layering along block margins. Hammer is ∼30 cm long. (D) Highlighting of C showing metavolcanic block (green), leucocratic granitic material along block margin (orange), and two sets of magmatic layering that formed along block margins (dashed and dotted black lines). Some erosion of older layers and crosscutting relationships indicate that dotted layers formed first, then the dashed. Both sets of magmatic layering contain pieces of partially melted(?) metavolcanic block material forming diffuse metavolcanic fragments. Graded magmatic layers form where more mafic material accumulated at the bottom of the layer. Magmatic foliation crosscuts all structure (lithologic contacts, magmatic layering) and strikes approximately north-south in photo.]()
![(A–R) Structural data from the Jackass Lakes pluton (JLP) and host rock plotted on lower-hemisphere, equal-area stereonets. Circles—poles to planar data; squares—linear data. Symbol colors are matched to units in Figure 2. In plots combining filled and open symbols, filled symbol—JLP and open symbol—other intrusive units in Figure 2 map area, often associated with the JLP (e.g., Madera Creek quartz diorite, Long Creek quartz diorite, Post Peak pluton). Unit abbreviations as in Figure 2. Note that J is a rose diagram of younging orientations.]()
![(A) Schematic diagram of a contact between Jackass Lakes pluton (JLP) and Madera Creek quartz diorite (MCQD) with hybrids of both units between them. Photomicrographs in plane polarized light of all units found along this contact. (B) Photo of sharp contact between hybrid units; all contacts from A are sharp. (C) Photo of hybrid MCQD with enclaves of MCQD as depicted in A. Scale card is 9 cm long.]()
![(A) Mineral and enclave foliation in the Jackass Lakes pluton (JLP); pen shows approximate dip of the foliation plane, which strikes 177°. Scale card is 9 cm long. (B) Combined photomicrograph (plane and cross-polarized light) of JLP magmatic texture and associated magmatic fabric. (C) Mineral and enclave foliations with different orientations; red pen shows strike of mineral foliation. Scale card is 9 cm long. (D) Magmatic foliation that crosscuts internal contact within the JLP. Fabric orientation remains consistent right up to the contact. Scale of rule is 15 cm.]()
![(A–R) Structural data from the Jackass Lakes pluton (JLP) and host rock plotted on lower-hemisphere, equal-area stereonets. Circles—poles to planar data; squares—linear data. Symbol colors are matched to units in Figure 2. In plots combining filled and open symbols, filled symbol—JLP and open symbol—other intrusive units in Figure 2 map area, often associated with the JLP (e.g., Madera Creek quartz diorite, Long Creek quartz diorite, Post Peak pluton). Unit abbreviations as in Figure 2. Note that J is a rose diagram of younging orientations.]()
![Evidence of stoping in the Jackass Lakes pluton (JLP). (A) Stoping near the eastern margin of the JLP with 2 large blocks of metavolcanics (MV) of different lithologies and an earlier plutonic unit (Long Creek quartz diorite, LCQD). Height of photo is ∼1.5 m. (B) Large block consisting of two earlier phases of the JLP that are fully contained within the JLP. Black dashed line indicates the contact between the block and JLP; the white dashed line is an internal boundary. Scale card is 9 cm long. (C) Metarhyolite block that disrupts foliation and layering within the JLP. Photo taken of a steeply inclined face, looking north. Scale card is 9 cm long. (D) Folded dike of JLP in a metarhyolite block found in the southwestern JLP. Foliation in dike is axial planar and parallel to metavolcanic foliation and magmatic foliation of JLP surrounding block. Photo looking east.]()
![Location map for the Jackass Lakes pluton (JLP) including trends of foliation in pluton and host rock and U-Pb ages. Kmg—Mount Givens granodiorite; Khd—Half Dome granodiorite; Krd—granodiorite of Red Devil Lake; Ktl—porphyritic granite of Turner Lake; Ko—granodiorite of Ostrander Lake; Ki—granodiorite of Illilouette Creek; BCSZ—Bench Canyon shear zone; SF—San Francisco; LA—Los Angeles. See text for details of U-Pb ages and general geologic relationships. Ages without location symbols are from outside the map area. Modified from McNulty et al. (1996) and Peck (1980).]()
![Photos showing evidence for pervasive mingling between Jackass Lakes pluton (JLP) internal units. (A) Mingled Madera Creek quartz diorite and JLP. (B) Mafic microgranitoid enclave swarm. Scale card is 9 cm long.]()
![(A–R) Structural data from the Jackass Lakes pluton (JLP) and host rock plotted on lower-hemisphere, equal-area stereonets. Circles—poles to planar data; squares—linear data. Symbol colors are matched to units in Figure 2. In plots combining filled and open symbols, filled symbol—JLP and open symbol—other intrusive units in Figure 2 map area, often associated with the JLP (e.g., Madera Creek quartz diorite, Long Creek quartz diorite, Post Peak pluton). Unit abbreviations as in Figure 2. Note that J is a rose diagram of younging orientations.]()
![Evidence of stoping in the Jackass Lakes pluton (JLP). (A) Stoping near the eastern margin of the JLP with 2 large blocks of metavolcanics (MV) of different lithologies and an earlier plutonic unit (Long Creek quartz diorite, LCQD). Height of photo is ∼1.5 m. (B) Large block consisting of two earlier phases of the JLP that are fully contained within the JLP. Black dashed line indicates the contact between the block and JLP; the white dashed line is an internal boundary. Scale card is 9 cm long. (C) Metarhyolite block that disrupts foliation and layering within the JLP. Photo taken of a steeply inclined face, looking north. Scale card is 9 cm long. (D) Folded dike of JLP in a metarhyolite block found in the southwestern JLP. Foliation in dike is axial planar and parallel to metavolcanic foliation and magmatic foliation of JLP surrounding block. Photo looking east.]()
![(A) Schematic diagram of a contact between Jackass Lakes pluton (JLP) and Madera Creek quartz diorite (MCQD) with hybrids of both units between them. Photomicrographs in plane polarized light of all units found along this contact. (B) Photo of sharp contact between hybrid units; all contacts from A are sharp. (C) Photo of hybrid MCQD with enclaves of MCQD as depicted in A. Scale card is 9 cm long.]()
![(A) Mineral and enclave foliation in the Jackass Lakes pluton (JLP); pen shows approximate dip of the foliation plane, which strikes 177°. Scale card is 9 cm long. (B) Combined photomicrograph (plane and cross-polarized light) of JLP magmatic texture and associated magmatic fabric. (C) Mineral and enclave foliations with different orientations; red pen shows strike of mineral foliation. Scale card is 9 cm long. (D) Magmatic foliation that crosscuts internal contact within the JLP. Fabric orientation remains consistent right up to the contact. Scale of rule is 15 cm.]()
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![Field photos from Jackass Lakes area. Hammers (30 cm long) or rulers (15 cm long) for scale. (A) Orthogonal dikes of Jackass Lakes pluton in metavolcanic block. (B) Triangular blocks at corners formed in volcanic block by the intrusion of thin Jackass Lakes pluton veins. (C) Small volcanic blocks ripped off larger volcanic block. (D) Jackass Lakes pluton dike intruding metavolcanic pendant with small pieces of metavolcanic fragments. Field photos from Jackass Lakes area. Hammers (30 cm long) or rulers (15 cm long) for scale. (E) Small leucocratic veins of Jackass Lakes pluton melts in metavolcanic host rocks (near eastern margin of Jackass Lakes pluton) in which veins were intruded during active deformation of the host rock. (F) Small leucocratic veins in metavolcaniclastic host rock that was undergoing folding. (G) Granodiorite (eastern margin of Jackass Lakes pluton) full of metavolcanic host-rock fragments. (H) Large magmatically folded dike of Jackass Lakes pluton in deformed metavolcanic block in Jackass Lakes pluton.]()
1-20 OF 103 RESULTS FOR
Jackass Lakes Pluton
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Journal Article
Structures in the Jackass Lakes pluton–host-rock system, central Sierra Nevada, California, and inferred mid-Cretaceous Farallon–North America plate kinematics Available to Purchase
Journal: GSA Bulletin
Publisher: Geological Society of America
Published: 29 June 2018
GSA Bulletin (2018) 130 (11-12): 1940–1958.
...Ryan J. Krueger; Aaron S. Yoshinobu Abstract Structures within the Jackass Lakes granodiorite pluton–host-rock system, central Sierra Nevada, California, record regional deformation that was contemporaneous with magma chamber construction and may have been related to mid-Cretaceous plate motions...
FIGURES
Journal Article
Processes involved during incremental growth of the Jackass Lakes pluton, central Sierra Nevada batholith Open Access
Journal: Geosphere
Publisher: Geological Society of America
Published: 01 April 2010
Geosphere (2010) 6 (2): 130–159.
...G.S. Pignotta; S.R. Paterson; C.C. Coyne; J.L. Anderson; J. Onezime Abstract The Jackass Lakes pluton (JLP), located in the central Sierra Nevada batholith, is a 98 Ma composite intrusion that preserves field, structural, and petrologic evidence of how incrementally emplaced plutons grow and evolve...
FIGURES
Includes: Supplemental Content
Journal Article
Assembly of a dike-fed magma chamber: The Jackass Lakes pluton, central Sierra Nevada, California Available to Purchase
Journal: GSA Bulletin
Publisher: Geological Society of America
Published: 01 August 1996
GSA Bulletin (1996) 108 (8): 926–940.
... of structural and petrologic fabrics in the middle Cretaceous Jackass Lakes pluton-wall-rock system, central Sierra Nevada, California, coupled with U-Pb geochronology, indicates that the pluton formed via sheet-like assembly of a dike-fed magma chamber. Final emplacement of the pluton was facilitated...
Image
Simplified geologic map of the Jackass Lakes pluton and host rocks and loca... Available to Purchase
in Structures in the Jackass Lakes pluton–host-rock system, central Sierra Nevada, California, and inferred mid-Cretaceous Farallon–North America plate kinematics
> GSA Bulletin
Published: 29 June 2018
Figure 2. Simplified geologic map of the Jackass Lakes pluton and host rocks and location of detailed mapping of Sing Peak pendant (see Fig. 3 ), modified from Peck (1980) .
Image
(A) Map of Jackass Lakes pluton after Pignotta et al. (2010) . See Figure... Open Access
in Formation and transfer of stoped blocks into magma chambers: The high-temperature interplay between focused porous flow, cracking, channel flow, host-rock anisotropy, and regional deformation
> Geosphere
Published: 01 April 2012
Figure 8. (A) Map of Jackass Lakes pluton after Pignotta et al. (2010) . See Figure 1 for location. Note large pendants and smaller blocks in the Jackass Lakes pluton. UTM—Universal Transverse Mercator coordinates. (B) Grid map of metavolcanic block formation in Jackass Lakes granodiorite
Image
(A) Map of Jackass Lakes pluton after Pignotta et al. (2010) . See Figure... Open Access
in Formation and transfer of stoped blocks into magma chambers: The high-temperature interplay between focused porous flow, cracking, channel flow, host-rock anisotropy, and regional deformation
> Geosphere
Published: 01 April 2012
Figure 8. (A) Map of Jackass Lakes pluton after Pignotta et al. (2010) . See Figure 1 for location. Note large pendants and smaller blocks in the Jackass Lakes pluton. UTM—Universal Transverse Mercator coordinates. (B) Grid map of metavolcanic block formation in Jackass Lakes granodiorite
Image
(A–R) Structural data from the Jackass Lakes pluton (JLP) and host rock plo... Open Access
in Processes involved during incremental growth of the Jackass Lakes pluton, central Sierra Nevada batholith
> Geosphere
Published: 01 April 2010
Figure 8. (A–R) Structural data from the Jackass Lakes pluton (JLP) and host rock plotted on lower-hemisphere, equal-area stereonets. Circles—poles to planar data; squares—linear data. Symbol colors are matched to units in Figure 2 . In plots combining filled and open symbols, filled symbol—JLP
Image
(A) Schematic diagram of a contact between Jackass Lakes pluton (JLP) and M... Open Access
in Processes involved during incremental growth of the Jackass Lakes pluton, central Sierra Nevada batholith
> Geosphere
Published: 01 April 2010
Figure 5. (A) Schematic diagram of a contact between Jackass Lakes pluton (JLP) and Madera Creek quartz diorite (MCQD) with hybrids of both units between them. Photomicrographs in plane polarized light of all units found along this contact. (B) Photo of sharp contact between hybrid units; all
Image
(A) Mineral and enclave foliation in the Jackass Lakes pluton (JLP); pen sh... Open Access
in Processes involved during incremental growth of the Jackass Lakes pluton, central Sierra Nevada batholith
> Geosphere
Published: 01 April 2010
Figure 7. (A) Mineral and enclave foliation in the Jackass Lakes pluton (JLP); pen shows approximate dip of the foliation plane, which strikes 177°. Scale card is 9 cm long. (B) Combined photomicrograph (plane and cross-polarized light) of JLP magmatic texture and associated magmatic fabric. (C
Image
(A–R) Structural data from the Jackass Lakes pluton (JLP) and host rock plo... Open Access
in Processes involved during incremental growth of the Jackass Lakes pluton, central Sierra Nevada batholith
> Geosphere
Published: 01 April 2010
Figure 8. (A–R) Structural data from the Jackass Lakes pluton (JLP) and host rock plotted on lower-hemisphere, equal-area stereonets. Circles—poles to planar data; squares—linear data. Symbol colors are matched to units in Figure 2 . In plots combining filled and open symbols, filled symbol—JLP
Image
Evidence of stoping in the Jackass Lakes pluton (JLP). (A) Stoping near the... Open Access
in Processes involved during incremental growth of the Jackass Lakes pluton, central Sierra Nevada batholith
> Geosphere
Published: 01 April 2010
Figure 12. Evidence of stoping in the Jackass Lakes pluton (JLP). (A) Stoping near the eastern margin of the JLP with 2 large blocks of metavolcanics (MV) of different lithologies and an earlier plutonic unit (Long Creek quartz diorite, LCQD). Height of photo is ∼1.5 m. (B) Large block consisting
Image
Location map for the Jackass Lakes pluton (JLP) including trends of foliati... Open Access
in Processes involved during incremental growth of the Jackass Lakes pluton, central Sierra Nevada batholith
> Geosphere
Published: 01 April 2010
Figure 1. Location map for the Jackass Lakes pluton (JLP) including trends of foliation in pluton and host rock and U-Pb ages. Kmg—Mount Givens granodiorite; Khd—Half Dome granodiorite; Krd—granodiorite of Red Devil Lake; Ktl—porphyritic granite of Turner Lake; Ko—granodiorite of Ostrander Lake
Image
Photos showing evidence for pervasive mingling between Jackass Lakes pluton... Open Access
in Processes involved during incremental growth of the Jackass Lakes pluton, central Sierra Nevada batholith
> Geosphere
Published: 01 April 2010
Figure 4. Photos showing evidence for pervasive mingling between Jackass Lakes pluton (JLP) internal units. (A) Mingled Madera Creek quartz diorite and JLP. (B) Mafic microgranitoid enclave swarm. Scale card is 9 cm long.
Image
(A–R) Structural data from the Jackass Lakes pluton (JLP) and host rock plo... Open Access
in Processes involved during incremental growth of the Jackass Lakes pluton, central Sierra Nevada batholith
> Geosphere
Published: 01 April 2010
Figure 8. (A–R) Structural data from the Jackass Lakes pluton (JLP) and host rock plotted on lower-hemisphere, equal-area stereonets. Circles—poles to planar data; squares—linear data. Symbol colors are matched to units in Figure 2 . In plots combining filled and open symbols, filled symbol—JLP
Image
Evidence of stoping in the Jackass Lakes pluton (JLP). (A) Stoping near the... Open Access
in Processes involved during incremental growth of the Jackass Lakes pluton, central Sierra Nevada batholith
> Geosphere
Published: 01 April 2010
Figure 12. Evidence of stoping in the Jackass Lakes pluton (JLP). (A) Stoping near the eastern margin of the JLP with 2 large blocks of metavolcanics (MV) of different lithologies and an earlier plutonic unit (Long Creek quartz diorite, LCQD). Height of photo is ∼1.5 m. (B) Large block consisting
Image
(A) Schematic diagram of a contact between Jackass Lakes pluton (JLP) and M... Open Access
in Processes involved during incremental growth of the Jackass Lakes pluton, central Sierra Nevada batholith
> Geosphere
Published: 01 April 2010
Figure 5. (A) Schematic diagram of a contact between Jackass Lakes pluton (JLP) and Madera Creek quartz diorite (MCQD) with hybrids of both units between them. Photomicrographs in plane polarized light of all units found along this contact. (B) Photo of sharp contact between hybrid units; all
Image
(A) Mineral and enclave foliation in the Jackass Lakes pluton (JLP); pen sh... Open Access
in Processes involved during incremental growth of the Jackass Lakes pluton, central Sierra Nevada batholith
> Geosphere
Published: 01 April 2010
Figure 7. (A) Mineral and enclave foliation in the Jackass Lakes pluton (JLP); pen shows approximate dip of the foliation plane, which strikes 177°. Scale card is 9 cm long. (B) Combined photomicrograph (plane and cross-polarized light) of JLP magmatic texture and associated magmatic fabric. (C
Image
JACKASS LAKES PLUTON STRAIN COMPILATION Open Access
in Processes involved during incremental growth of the Jackass Lakes pluton, central Sierra Nevada batholith
> Geosphere
Published: 01 April 2010
TABLE 1. JACKASS LAKES PLUTON STRAIN COMPILATION
Journal Article
Determining relative magma and host rock xenolith rheology during magmatic fabric formation in plutons: Examples from the middle and upper crust Open Access
Journal: Geosphere
Publisher: Geological Society of America
Published: 01 June 2009
Geosphere (2009) 5 (3): 270–285.
... plutons are examined, the subvolcanic 98 Ma old Jackass Lakes pluton, central Sierra Nevada, California, and the voluminous middle crustal 442 Ma old Andalshatten pluton, central Norway. The Andalshatten example contains millimeter- to kilometer-scale xenoliths that display evidence for synmagmatic...
FIGURES
Image
Field photos from Jackass Lakes area. Hammers (30 cm long) or rulers (15 cm... Open Access
in Formation and transfer of stoped blocks into magma chambers: The high-temperature interplay between focused porous flow, cracking, channel flow, host-rock anisotropy, and regional deformation
> Geosphere
Published: 01 April 2012
Figure 9. Field photos from Jackass Lakes area. Hammers (30 cm long) or rulers (15 cm long) for scale. (A) Orthogonal dikes of Jackass Lakes pluton in metavolcanic block. (B) Triangular blocks at corners formed in volcanic block by the intrusion of thin Jackass Lakes pluton veins. (C) Small
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