Paul Myrow - Academia.edu (original) (raw)
Papers by Paul Myrow
Geological Society, London, Special Publications, Jan 6, 2023
Ordovician rocks of the Indian Tethyan Himalaya contain a conspicuous angular unconformity betwee... more Ordovician rocks of the Indian Tethyan Himalaya contain a conspicuous angular unconformity between mostly marine Cambrian and overlying terrestrial Ordovician strata, which is a record of the Kurgiakh Orogeny. This tectonic event is traceable across the Tethyan Himalaya from Pakistan to Bhutan. The Pin Formation in the Spiti Valley provides a high-resolution account of the marine depositional history, palaeontology and isotope geochemistry of Late Ordovician events. The middle (Takche) member is late Katian and the upper Mikkim Member is lower Silurian (Llandovery), based on an ozarkodinid conodont fauna. The Pin Formation records the Boda event, the last warming interval prior to Hirnantian glaciation. The δ 13 C carb chemostratigraphic data allow precise global correlation, and recognition of the Paroveja positive excursion, the last major excursion of the Katian. The Mikkim Member records a ‘lower HICE’ (Hirnantian isotopic carbon excursion) of the Katian–Hirnantian boundary interval. Palaeontological data indicate that there are no known fossils diagnostic of any Ordovician ages older than the Katian Stage in India. Evidence of Ordovician sedimentary rocks in the Lesser Himalaya is intriguing, but presently equivocal. The widespread absence of pre-Katian strata on the Indian subcontinent is due to erosion associated with the Kurghiak orogeny and delayed onlap onto topographically high areas.
Sedimentary Geology, Dec 1, 2021
The Hecla Hoek succession of northeastern Svalbard, Norway, is an~7 km thick Tonian-Ordovician se... more The Hecla Hoek succession of northeastern Svalbard, Norway, is an~7 km thick Tonian-Ordovician sedimentary succession that overlies Stenian-Tonian felsic igneous and metasedimentary rocks. The carbonate-dominated upper Tonian-Ediacaran (ca. 820-600 Ma) Akademikerbreen and Polarisbreen groups have yielded important insights into Earth's Neoproterozoic climate, environment, and biological evolution. However, the underlying siliciclastic-dominated lower Tonian (ca. 950-820 Ma) Veteranen Group has garnered little attention despite the fact that it is remarkably well-preserved and hosts diverse microfossil assemblages. Here, we present the first detailed sedimentological analysis of the Veteranen Group from a continuous~4.4 km thick stratigraphic section at Faksevågen, Ny Friesland, Spitsbergen. Integrated facies analysis, sequence stratigraphy, and carbonate δ 13 C carb and δ 18 O carb chemostratigraphy elucidate the early depositional history of the Hecla Hoek basin and provide fundamental paleoenvironmental constraints for future investigations of this succession as an archive of Tonian Earth History. The Veteranen Group records a long-lived deltaic and storm-influenced marine sedimentary system that reveals dynamics of Precambrian clastic sedimentation prior to the evolution of land plants. Five asymmetric transgressive-regressive (T-R) sequences within the Veteranen Group thin upwards, providing support for the hypothesis that the contact with the Akademikerbreen Group represents a rift-to-drift transition. This complex record of Tonian deltaic and storm-influenced marine sedimentation along the Laurentian margin strengthens correlation between the Veteranen Group and coeval strata from East Greenland and sets the stage to better understand the Proterozoic tectonic evolution of the North Atlantic-circum-Arctic region following the Grenville orogeny.
Journal of Paleontology, 2016
I would like to acknowledge, with sincere gratitude, and in enormous debt of thanks, Nigel Hughes... more I would like to acknowledge, with sincere gratitude, and in enormous debt of thanks, Nigel Hughes. It is due his immensity of knowledge, encouragement, and most important of all, patience, that I am submitting this thesis today. I would also like to thank my thesis committee members, Peter M. Sadler and Mary L. Droser for taking time out of their incredibly busy schedules to suggest apt revisions. In addition, I would like to thank John Moore for his willingness to share his expertise in coeloscleritophorans, as well as lending me an article database that consisted of hundreds upon hundreds of outstanding, and very difficult to find, small shelly fossil papers. Last but not least, would also like to thank my incredible wife, family, and friends for all of their love and support throughout this whole process. v v
AGU Fall Meeting Abstracts, Dec 1, 2012
Journal of Asian Earth Sciences, Jul 1, 2021
Abstract The existence of late Cambrian (Furongian) trilobites in Myanmar (Burma) has been acknow... more Abstract The existence of late Cambrian (Furongian) trilobites in Myanmar (Burma) has been acknowledged since the 1970s, but no formal systematic descriptions of such fossils have been published to date. Herein, we provide such descriptions of some trilobites from the Molohein Group’s Myet-Ye Formation from the Linwe area, Ye-Ngan Township of the southern Shan State. Three species from two genera are reported: Asioptychaspis (A. asiatica, previously known from the North China Block, and a new species, A. lata) and Eosaukia buravasi, also known from peninsular Thailand. The Molohein Group was initially assigned a late Cambrian age based on the reported, but unsubstantiated, occurrence of the Laurentian genera Saukiella and Drumaspis, and this age assessment is supported by the fauna we present, although Saukiella or Drumaspis remain unconfirmed from Myanmar. Asioptychaspis asiatica first appears in late Jiangshanian strata, and Eosaukia buravasi ranges up to the middle of Stage 10. Thus these ranges provide a more specific constraint on the age of the Molohein Group. Similarities are strong between upper Cambrian and Lower Ordovician successions in Sibumasu and northwestern Australia, particularly those from the Canning Basin succession. Regional geological data supports placement of Sibumasu adjacent to western Australia during the Cambrian, without the Lhasa Block intervening between them, and Baoshan at the western end of Sibumasu during the early Paleozoic, towards the Himalayan margin. The new Burmese fauna is consistent with these suggestions, as they belong to the Sino-Australian faunal province.
Geobiology, Apr 3, 2020
Morphologically complex trace fossils, recording the infaunal activities of bilaterian animals, a... more Morphologically complex trace fossils, recording the infaunal activities of bilaterian animals, are common in Phanerozoic successions but rare in the Ediacaran fossil record. Here, we describe a trace fossil assemblage from the lower Dunfee Member of the Deep Spring Formation at Mount Dunfee (Nevada, USA), over 500 m below the Ediacaran-Cambrian boundary. Although millimetric in scale and largely not fabricdisruptive, the Dunfee assemblage includes complex and sediment-penetrative trace fossil morphologies that are characteristic of Cambrian deposits. The Dunfee assemblage records one of the oldest documented instances of sediment-penetrative infaunalization, corroborating previous molecular, ichnologic, and paleoecological data suggesting that crown-group bilaterians and bilaterian-style ecologies were present in late Ediacaran shallow marine ecosystems. Moreover, Dunfee trace fossils co-occur with classic upper Ediacaran tubular body fossils in multiple horizons, indicating that Ediacaran infauna and epifauna coexisted and likely formed stable ecosystems.
Geological Society, London, Special Publications, Nov 21, 2018
Reconstructing the stratigraphic architecture of deposits prior to Cenozoic Himalayan uplift is c... more Reconstructing the stratigraphic architecture of deposits prior to Cenozoic Himalayan uplift is critical for unravelling the structural, metamorphic, depositional and erosional history of the orogen. The nature and distribution of Proterozoic and lower Paleozoic strata have helped elucidate the relationship between lithotectonic zones, as well as the geometries of major bounding faults. Stratigraphic and geochronological work has revealed a uniform and widespread pattern of Paleoproterozoic strata >1.6 Ga that are unconformably overlain by <1.1 Ga rocks. The overlying Neoproterozoic strata record marine sedimentation, including a Cryogenian diamictite, a well-developed carbonate platform succession and condensed fossiliferous Precambrian–Cambrian boundary strata. Palaeontological study of Cambrian units permits correlation from the Indian craton through three Himalayan lithotectonic zones to a precision of within a few million years. Detailed sedimentological and stratigraphic analysis shows the differentiation of a proximal realm of relatively condensed, nearshore, evaporite-rich units to the south and a distal realm of thick, deltaic deposits to the north. Thus, Neoproterozoic and Cambrian strata blanketed the northern Indian craton with an extensive, northward-deepening, succession. Today, these rocks are absent from parts of the inner Lesser Himalaya, and the uplift and erosion of these proximal facies explains a marked change in global seawater isotopic chemistry at 16 Ma.
Geology
The Cambrian transgression across the Great Unconformity produced one of the largest expansions o... more The Cambrian transgression across the Great Unconformity produced one of the largest expansions of shallow marine habitats and associated diversification of marine invertebrate faunas in Earth history. However, identification of the underlying controls on the pattern of transgression of Cambrian seas has been hampered by imprecise or inaccurate age assignments for many formations. Recovery of an Ehmaniella Zone trilobite fauna from the Lodore Formation in northwestern Colorado (United States) revises the age of this unit to be significantly older, specifically middle Miaolingian (upper Wuliuan). This expands the established distribution of thick Miaolingian deposits of the northern Rocky Mountains to within 90 km of a broad region of central Colorado where Miaolingian strata are missing and Furongian successions rest directly on basement. The boundary between these two regions marks the position of an ~200 km east-west offset within the generally north-south–trending Cambrian paleos...
Palaeogeography, Palaeoclimatology, Palaeoecology
Geological Society, London, Special Publications
Orientated carbonate (calcite twinning strains; n = 78 with 2414 twin measurements) and quartzite... more Orientated carbonate (calcite twinning strains; n = 78 with 2414 twin measurements) and quartzites (finite strains; n = 15) were collected around Gondwana to study the deformational history associated with the amalgamation of the supercontinent. The Buzios orogen (545–500 Ma), within interior Gondwana, records the high-grade collisional orogen between the São Francisco Craton (Brazil) and the Congo–Angola Craton (Angola and Namibia), and twinning strains in calc-silicates record a SE–NW shortening fabric parallel to the thrust transport. Along Gondwana's southern margin, the Saldanian–Ross–Delamerian orogen (590–480 Ma) is marked by a regional unconformity that cuts into deformed Neoproterozoic–Ordovician sedimentary rocks and associated intrusions. Cambrian carbonate is preserved in the central part of the southern Gondwana margin, namely in the Kango Inlier of the Cape Fold Belt and the Ellsworth, Pensacola and Transantarctic mountains. Paleozoic carbonate is not preserved in ...
1University of Hong Kong, Pokfulam, Hong Kong, ryan00@hku.hk 2Virginia Polytechnic Institute and ... more 1University of Hong Kong, Pokfulam, Hong Kong, ryan00@hku.hk 2Virginia Polytechnic Institute and State University, Blacksburg VT USA, bcgill@vt.edu 3University of California, Riverside, Rivside CA USA, swern001@ucr.edu 4Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, China, jitaochen@126.com 5Korea Polar Research Institute, Incheon, Republic of Korea, typark@kopri.re.kr 6Colorado College, Colorado Springs, CO USA, pmyrow@coloradocollege.edu 7University of California, Riverside, Rivside CA USA, hughesnc@ucr.edu
Geological Magazine, 2021
Later Cambrian and earliest Ordovician trilobites and brachiopods spanning eight horizons from fi... more Later Cambrian and earliest Ordovician trilobites and brachiopods spanning eight horizons from five localities within the Sông Mã, Hàm Rồng and Đông Sơn formations of the Thanh Hóa province of Việt Nam, constrain the age and faunal affinities of rocks within the Sông Đà terrane, one of several suture/fault-bounded units situated between South China to the north and Indochina to the south. ‘Ghost-like’ preservation in dolomite coupled with tectonic deformation leaves many of the fossils poorly preserved, and poor exposure precludes collecting within continuously exposed stratigraphic successions. Cambrian carbonate facies pass conformably into Lower Ordovician carbonate-rich strata that also include minor siliciclastic facies, and the recovered fauna spans several uppermost Cambrian and Lower Ordovician biozones. The fauna is of equatorial Gondwanan affinity, and comparable to that from South China, North China, Sibumasu and Australia. A new species of Miaolingian ‘ptychopariid’ tril...
Proceedings of the Indian National Science Academy, 2020
This paper summarises the work done during last four years on stratigraphy and biostratigraphy of... more This paper summarises the work done during last four years on stratigraphy and biostratigraphy of the Proterozoic sedimentary deposits of Himalaya. The Palaeoproterozoic and Mesoproterozoic sediments are more or less restricted to the Lesser Himalayan belt but the Neoproterozoic rocks are known from all the sectors of the Himalaya including Tethyan Himalaya. The Lesser Himalayan succession has been sudivided into Outer Lesser Himalayan Belt and Inner Lesser Himalayan Belt. Attempt has been made to correlate the stratigraphic units of these belts on the basis of lithology, structural setting, isotope geochemistry and biostratigraphy. The Pre-Ediacaran sediments of the Lesser Himalaya of NW and NE were studied for microbial life, stromatolites and isotope chemostratigraphy. Astrobiological implications were also considered for the microfossil community discovered from the chert deposits of the ancient rocks. Palaeoclimate for the Proterozoic era of the Himalaya is established for the first time.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
GSA Bulletin, 2019
In our 2019 paper on the Salt Range of Pakistan (Hughes et al., 2019, p. 1108), we wrote, "Recogn... more In our 2019 paper on the Salt Range of Pakistan (Hughes et al., 2019, p. 1108), we wrote, "Recognizing significant geological differences between neighboring rocks separated by a major high-strain zone is, according to Martin (2017, p. 62), fundamental to terrane recognition." Martin's (2017) contention had been that the Salt Range thrust provides such a case, but his response to our paper reports no data suggesting significant geological differences across this structure. To do so would be challenging because, as we reported in our paper (Hughes et al., 2019), two boreholes drilled on either side of the thrust, located less than 25 km apart, reveal the same stratigraphy in terms of the rock succession, unit thickness, detrital zircon spectra, and depositional age of both hanging-wall and footwall rocks (Siddiqui, 2012, fig. 5; Hughes et al., 2019, figs. 3, 4, 11, and 12). The suite of rocks shared on both sides of the fault includes a distinctive 1000-m-thick evaporite succession, an overlying 200-m-thick sandstone, and then a transition to carbonate. Accordingly, by Martin's own definition of a terrane boundary, the Salt Range thrust is excluded. In his response to our paper, and in order to preserve the terrane model, Martin relaxes the requirement for significant geological differences between adjacent terranes and instead claims that lateral displacement of several thousand kilometers along a transform fault resulted in two successions being juxtaposed-two successions that are so similar that they cannot be distinguished. A parsimonious alternative explanation, that there is no terrane boundary along the Salt Range thrust, is the explanation that we offered in our paper. We stand by that interpretation for the reasons presented in our paper and expanded upon below. We also
Geological Society, London, Special Publications, Jan 6, 2023
Ordovician rocks of the Indian Tethyan Himalaya contain a conspicuous angular unconformity betwee... more Ordovician rocks of the Indian Tethyan Himalaya contain a conspicuous angular unconformity between mostly marine Cambrian and overlying terrestrial Ordovician strata, which is a record of the Kurgiakh Orogeny. This tectonic event is traceable across the Tethyan Himalaya from Pakistan to Bhutan. The Pin Formation in the Spiti Valley provides a high-resolution account of the marine depositional history, palaeontology and isotope geochemistry of Late Ordovician events. The middle (Takche) member is late Katian and the upper Mikkim Member is lower Silurian (Llandovery), based on an ozarkodinid conodont fauna. The Pin Formation records the Boda event, the last warming interval prior to Hirnantian glaciation. The δ 13 C carb chemostratigraphic data allow precise global correlation, and recognition of the Paroveja positive excursion, the last major excursion of the Katian. The Mikkim Member records a ‘lower HICE’ (Hirnantian isotopic carbon excursion) of the Katian–Hirnantian boundary interval. Palaeontological data indicate that there are no known fossils diagnostic of any Ordovician ages older than the Katian Stage in India. Evidence of Ordovician sedimentary rocks in the Lesser Himalaya is intriguing, but presently equivocal. The widespread absence of pre-Katian strata on the Indian subcontinent is due to erosion associated with the Kurghiak orogeny and delayed onlap onto topographically high areas.
Sedimentary Geology, Dec 1, 2021
The Hecla Hoek succession of northeastern Svalbard, Norway, is an~7 km thick Tonian-Ordovician se... more The Hecla Hoek succession of northeastern Svalbard, Norway, is an~7 km thick Tonian-Ordovician sedimentary succession that overlies Stenian-Tonian felsic igneous and metasedimentary rocks. The carbonate-dominated upper Tonian-Ediacaran (ca. 820-600 Ma) Akademikerbreen and Polarisbreen groups have yielded important insights into Earth's Neoproterozoic climate, environment, and biological evolution. However, the underlying siliciclastic-dominated lower Tonian (ca. 950-820 Ma) Veteranen Group has garnered little attention despite the fact that it is remarkably well-preserved and hosts diverse microfossil assemblages. Here, we present the first detailed sedimentological analysis of the Veteranen Group from a continuous~4.4 km thick stratigraphic section at Faksevågen, Ny Friesland, Spitsbergen. Integrated facies analysis, sequence stratigraphy, and carbonate δ 13 C carb and δ 18 O carb chemostratigraphy elucidate the early depositional history of the Hecla Hoek basin and provide fundamental paleoenvironmental constraints for future investigations of this succession as an archive of Tonian Earth History. The Veteranen Group records a long-lived deltaic and storm-influenced marine sedimentary system that reveals dynamics of Precambrian clastic sedimentation prior to the evolution of land plants. Five asymmetric transgressive-regressive (T-R) sequences within the Veteranen Group thin upwards, providing support for the hypothesis that the contact with the Akademikerbreen Group represents a rift-to-drift transition. This complex record of Tonian deltaic and storm-influenced marine sedimentation along the Laurentian margin strengthens correlation between the Veteranen Group and coeval strata from East Greenland and sets the stage to better understand the Proterozoic tectonic evolution of the North Atlantic-circum-Arctic region following the Grenville orogeny.
Journal of Paleontology, 2016
I would like to acknowledge, with sincere gratitude, and in enormous debt of thanks, Nigel Hughes... more I would like to acknowledge, with sincere gratitude, and in enormous debt of thanks, Nigel Hughes. It is due his immensity of knowledge, encouragement, and most important of all, patience, that I am submitting this thesis today. I would also like to thank my thesis committee members, Peter M. Sadler and Mary L. Droser for taking time out of their incredibly busy schedules to suggest apt revisions. In addition, I would like to thank John Moore for his willingness to share his expertise in coeloscleritophorans, as well as lending me an article database that consisted of hundreds upon hundreds of outstanding, and very difficult to find, small shelly fossil papers. Last but not least, would also like to thank my incredible wife, family, and friends for all of their love and support throughout this whole process. v v
AGU Fall Meeting Abstracts, Dec 1, 2012
Journal of Asian Earth Sciences, Jul 1, 2021
Abstract The existence of late Cambrian (Furongian) trilobites in Myanmar (Burma) has been acknow... more Abstract The existence of late Cambrian (Furongian) trilobites in Myanmar (Burma) has been acknowledged since the 1970s, but no formal systematic descriptions of such fossils have been published to date. Herein, we provide such descriptions of some trilobites from the Molohein Group’s Myet-Ye Formation from the Linwe area, Ye-Ngan Township of the southern Shan State. Three species from two genera are reported: Asioptychaspis (A. asiatica, previously known from the North China Block, and a new species, A. lata) and Eosaukia buravasi, also known from peninsular Thailand. The Molohein Group was initially assigned a late Cambrian age based on the reported, but unsubstantiated, occurrence of the Laurentian genera Saukiella and Drumaspis, and this age assessment is supported by the fauna we present, although Saukiella or Drumaspis remain unconfirmed from Myanmar. Asioptychaspis asiatica first appears in late Jiangshanian strata, and Eosaukia buravasi ranges up to the middle of Stage 10. Thus these ranges provide a more specific constraint on the age of the Molohein Group. Similarities are strong between upper Cambrian and Lower Ordovician successions in Sibumasu and northwestern Australia, particularly those from the Canning Basin succession. Regional geological data supports placement of Sibumasu adjacent to western Australia during the Cambrian, without the Lhasa Block intervening between them, and Baoshan at the western end of Sibumasu during the early Paleozoic, towards the Himalayan margin. The new Burmese fauna is consistent with these suggestions, as they belong to the Sino-Australian faunal province.
Geobiology, Apr 3, 2020
Morphologically complex trace fossils, recording the infaunal activities of bilaterian animals, a... more Morphologically complex trace fossils, recording the infaunal activities of bilaterian animals, are common in Phanerozoic successions but rare in the Ediacaran fossil record. Here, we describe a trace fossil assemblage from the lower Dunfee Member of the Deep Spring Formation at Mount Dunfee (Nevada, USA), over 500 m below the Ediacaran-Cambrian boundary. Although millimetric in scale and largely not fabricdisruptive, the Dunfee assemblage includes complex and sediment-penetrative trace fossil morphologies that are characteristic of Cambrian deposits. The Dunfee assemblage records one of the oldest documented instances of sediment-penetrative infaunalization, corroborating previous molecular, ichnologic, and paleoecological data suggesting that crown-group bilaterians and bilaterian-style ecologies were present in late Ediacaran shallow marine ecosystems. Moreover, Dunfee trace fossils co-occur with classic upper Ediacaran tubular body fossils in multiple horizons, indicating that Ediacaran infauna and epifauna coexisted and likely formed stable ecosystems.
Geological Society, London, Special Publications, Nov 21, 2018
Reconstructing the stratigraphic architecture of deposits prior to Cenozoic Himalayan uplift is c... more Reconstructing the stratigraphic architecture of deposits prior to Cenozoic Himalayan uplift is critical for unravelling the structural, metamorphic, depositional and erosional history of the orogen. The nature and distribution of Proterozoic and lower Paleozoic strata have helped elucidate the relationship between lithotectonic zones, as well as the geometries of major bounding faults. Stratigraphic and geochronological work has revealed a uniform and widespread pattern of Paleoproterozoic strata >1.6 Ga that are unconformably overlain by <1.1 Ga rocks. The overlying Neoproterozoic strata record marine sedimentation, including a Cryogenian diamictite, a well-developed carbonate platform succession and condensed fossiliferous Precambrian–Cambrian boundary strata. Palaeontological study of Cambrian units permits correlation from the Indian craton through three Himalayan lithotectonic zones to a precision of within a few million years. Detailed sedimentological and stratigraphic analysis shows the differentiation of a proximal realm of relatively condensed, nearshore, evaporite-rich units to the south and a distal realm of thick, deltaic deposits to the north. Thus, Neoproterozoic and Cambrian strata blanketed the northern Indian craton with an extensive, northward-deepening, succession. Today, these rocks are absent from parts of the inner Lesser Himalaya, and the uplift and erosion of these proximal facies explains a marked change in global seawater isotopic chemistry at 16 Ma.
Geology
The Cambrian transgression across the Great Unconformity produced one of the largest expansions o... more The Cambrian transgression across the Great Unconformity produced one of the largest expansions of shallow marine habitats and associated diversification of marine invertebrate faunas in Earth history. However, identification of the underlying controls on the pattern of transgression of Cambrian seas has been hampered by imprecise or inaccurate age assignments for many formations. Recovery of an Ehmaniella Zone trilobite fauna from the Lodore Formation in northwestern Colorado (United States) revises the age of this unit to be significantly older, specifically middle Miaolingian (upper Wuliuan). This expands the established distribution of thick Miaolingian deposits of the northern Rocky Mountains to within 90 km of a broad region of central Colorado where Miaolingian strata are missing and Furongian successions rest directly on basement. The boundary between these two regions marks the position of an ~200 km east-west offset within the generally north-south–trending Cambrian paleos...
Palaeogeography, Palaeoclimatology, Palaeoecology
Geological Society, London, Special Publications
Orientated carbonate (calcite twinning strains; n = 78 with 2414 twin measurements) and quartzite... more Orientated carbonate (calcite twinning strains; n = 78 with 2414 twin measurements) and quartzites (finite strains; n = 15) were collected around Gondwana to study the deformational history associated with the amalgamation of the supercontinent. The Buzios orogen (545–500 Ma), within interior Gondwana, records the high-grade collisional orogen between the São Francisco Craton (Brazil) and the Congo–Angola Craton (Angola and Namibia), and twinning strains in calc-silicates record a SE–NW shortening fabric parallel to the thrust transport. Along Gondwana's southern margin, the Saldanian–Ross–Delamerian orogen (590–480 Ma) is marked by a regional unconformity that cuts into deformed Neoproterozoic–Ordovician sedimentary rocks and associated intrusions. Cambrian carbonate is preserved in the central part of the southern Gondwana margin, namely in the Kango Inlier of the Cape Fold Belt and the Ellsworth, Pensacola and Transantarctic mountains. Paleozoic carbonate is not preserved in ...
1University of Hong Kong, Pokfulam, Hong Kong, ryan00@hku.hk 2Virginia Polytechnic Institute and ... more 1University of Hong Kong, Pokfulam, Hong Kong, ryan00@hku.hk 2Virginia Polytechnic Institute and State University, Blacksburg VT USA, bcgill@vt.edu 3University of California, Riverside, Rivside CA USA, swern001@ucr.edu 4Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, China, jitaochen@126.com 5Korea Polar Research Institute, Incheon, Republic of Korea, typark@kopri.re.kr 6Colorado College, Colorado Springs, CO USA, pmyrow@coloradocollege.edu 7University of California, Riverside, Rivside CA USA, hughesnc@ucr.edu
Geological Magazine, 2021
Later Cambrian and earliest Ordovician trilobites and brachiopods spanning eight horizons from fi... more Later Cambrian and earliest Ordovician trilobites and brachiopods spanning eight horizons from five localities within the Sông Mã, Hàm Rồng and Đông Sơn formations of the Thanh Hóa province of Việt Nam, constrain the age and faunal affinities of rocks within the Sông Đà terrane, one of several suture/fault-bounded units situated between South China to the north and Indochina to the south. ‘Ghost-like’ preservation in dolomite coupled with tectonic deformation leaves many of the fossils poorly preserved, and poor exposure precludes collecting within continuously exposed stratigraphic successions. Cambrian carbonate facies pass conformably into Lower Ordovician carbonate-rich strata that also include minor siliciclastic facies, and the recovered fauna spans several uppermost Cambrian and Lower Ordovician biozones. The fauna is of equatorial Gondwanan affinity, and comparable to that from South China, North China, Sibumasu and Australia. A new species of Miaolingian ‘ptychopariid’ tril...
Proceedings of the Indian National Science Academy, 2020
This paper summarises the work done during last four years on stratigraphy and biostratigraphy of... more This paper summarises the work done during last four years on stratigraphy and biostratigraphy of the Proterozoic sedimentary deposits of Himalaya. The Palaeoproterozoic and Mesoproterozoic sediments are more or less restricted to the Lesser Himalayan belt but the Neoproterozoic rocks are known from all the sectors of the Himalaya including Tethyan Himalaya. The Lesser Himalayan succession has been sudivided into Outer Lesser Himalayan Belt and Inner Lesser Himalayan Belt. Attempt has been made to correlate the stratigraphic units of these belts on the basis of lithology, structural setting, isotope geochemistry and biostratigraphy. The Pre-Ediacaran sediments of the Lesser Himalaya of NW and NE were studied for microbial life, stromatolites and isotope chemostratigraphy. Astrobiological implications were also considered for the microfossil community discovered from the chert deposits of the ancient rocks. Palaeoclimate for the Proterozoic era of the Himalaya is established for the first time.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
GSA Bulletin, 2019
In our 2019 paper on the Salt Range of Pakistan (Hughes et al., 2019, p. 1108), we wrote, "Recogn... more In our 2019 paper on the Salt Range of Pakistan (Hughes et al., 2019, p. 1108), we wrote, "Recognizing significant geological differences between neighboring rocks separated by a major high-strain zone is, according to Martin (2017, p. 62), fundamental to terrane recognition." Martin's (2017) contention had been that the Salt Range thrust provides such a case, but his response to our paper reports no data suggesting significant geological differences across this structure. To do so would be challenging because, as we reported in our paper (Hughes et al., 2019), two boreholes drilled on either side of the thrust, located less than 25 km apart, reveal the same stratigraphy in terms of the rock succession, unit thickness, detrital zircon spectra, and depositional age of both hanging-wall and footwall rocks (Siddiqui, 2012, fig. 5; Hughes et al., 2019, figs. 3, 4, 11, and 12). The suite of rocks shared on both sides of the fault includes a distinctive 1000-m-thick evaporite succession, an overlying 200-m-thick sandstone, and then a transition to carbonate. Accordingly, by Martin's own definition of a terrane boundary, the Salt Range thrust is excluded. In his response to our paper, and in order to preserve the terrane model, Martin relaxes the requirement for significant geological differences between adjacent terranes and instead claims that lateral displacement of several thousand kilometers along a transform fault resulted in two successions being juxtaposed-two successions that are so similar that they cannot be distinguished. A parsimonious alternative explanation, that there is no terrane boundary along the Salt Range thrust, is the explanation that we offered in our paper. We stand by that interpretation for the reasons presented in our paper and expanded upon below. We also