Depositional history of the southeastern outcrop belt of the Chuckanut Formation: implications for the Darrington – Devil's Mountain and Straight Creek fault zones, Washington (U.S.A.)

1994 ◽  
Vol 31 (12) ◽  
pp. 1727-1743 ◽  
Author(s):  
James E. Evans ◽  
R. John Ristow Jr.
Keyword(s):  
Fault Zone ◽  
Middle Eocene ◽  
Fault Zones ◽  
Early Eocene ◽  
Fluvial System ◽  
Sediment Sources ◽  
Depositional History ◽  
Source Areas ◽  
Depositional System ◽  
History Of

The southeastern outcrop belt of the Eocene Chuckanut Formation contains the erosional remnants of a larger depositional system. In the study area, the Chuckanut Formation can be split into four units based upon differences in age, lithology, sedimentology, paleocurrents, and provenance relationships. The Coal Mountain unit (Early Eocene) represents a southwest-flowing fluvial system that shows no evidence for fault control of drainage. The overlying Higgins Mountain unit (early Middle Eocene) represents a northeast-flowing fluvial system east of the Devil's Mountain fault zone (DMFZ), with lithologies derived from western source areas. The Sperry Peak unit (early Middle Eocene) represents a fluvial system with a wide dispersion of paleocurrent azimuths and a possible mixture of sediment source areas. We believe the Sperry Peak unit was deposited in a fault-wedge graben at the junction of the DMFZ and Straight Creek fault zone (SCFZ), with sediment sources from both east and west. The Grade Creek unit (age unknown) is a fluvial unit found along the trace of the SCFZ with paleo-flow subparallel to the fault zone. The sedimentary evidence suggests that onset of Paleogene faulting on the DMFZ and SCFZ was at about 50–48 Ma, while movement on the Darrington fault zone may have been later (post-42 Ma).

Early Tertiary thermotectonic history of the northern Yukon and adjacent Northwest Territories, Arctic Canada

1997 ◽  
Vol 34 (10) ◽  
pp. 1366-1378 ◽  
Author(s):  
Paul B. O'Sullivan ◽  
Larry S. Lane
Keyword(s):  
Northwest Territories ◽  
Fission Track ◽  
Middle Eocene ◽  
Geothermal Gradient ◽  
Crystalline Rock ◽  
Early Eocene ◽  
Channel Formation ◽  
Rapid Cooling ◽  
Early Tertiary ◽  
History Of

Apatite fission-track data from 16 sedimentary and crystalline rock samples indicate rapid regional Early Eocene denudation within the onshore Beaufort–Mackenzie region of northwestern Canada. Rocks exposed in the area of the Big Fish River, Northwest Territories, cooled rapidly from paleotemperatures of >80–110 °C to <6 0°C at ca. 56 ± 2 Ma, probably in response to kilometre-scale denudation associated with regional structuring. The data suggest the region experienced a geothermal gradient of ~28 °C/km prior to rapid cooling, with ~2.7 km of section having been removed from the top of the exposed section in the Moose Channel Formation and ~3.8 km from the top of the exposed Cuesta Creek Member. Farther to the west, rocks exposed in the headwaters of the Blow River in the Barn Mountains, Yukon Territories, were exposed to paleotemperatures above 110 °C in the Late Paleocene prior to rapid cooling from these elevated paleotemperatures due to kilometre-scale denudation at ca. 56 ± 2 Ma. Exposure of these samples at the surface today requires that a minimum of ~3.8 km of denudation occurred since they began cooling below ~110 °C. The apatite analyses indicate that rocks exposed in the northern Yukon and Northwest Territories experienced rapid cooling during the Early Eocene in response to kilometre-scale denudation, associated with early Tertiary folding and thrusting in the northern Cordillera. Early Eocene cooling–uplift ages for onshore sections are slightly older than the Middle Eocene ages previously documented for the adjacent offshore foldbelt and suggest that the deformation progressed toward the foreland of the foldbelt through time.

Depositional history of the early Eocene Shumaysi Formation, Saudi Arabia

Palynology ◽  
1991 ◽  
Vol 15 (1) ◽  
pp. 47-61 ◽  
Author(s):  
Satish K. Srivastava ◽  
Pier L. Binda
Keyword(s):  
Saudi Arabia ◽  
Early Eocene ◽  
Depositional History ◽  
History Of

Constraints from 40Ar/39Ar geochronology on the tectonothermal history of the Kapuskasing uplift in the Canadian Superior Province

1994 ◽  
Vol 31 (7) ◽  
pp. 1146-1171 ◽  
Author(s):  
J. A. Hanes ◽  
D. A. Archibald ◽  
M. Queen ◽  
E. Farrar
Keyword(s):  
Fault Zone ◽  
Age Groups ◽  
Fault Zones ◽  
Fault Reactivation ◽  
Superior Province ◽  
Lower Grade ◽  
Upper Limit ◽  
Step Heating ◽  
History Of ◽  
Structural Levels

The Kapuskasing uplift (KU) in the Superior Province of the Canadian Shield has been interpreted as an oblique cross section through the Archean mid-crust. However, the time of juxtaposition of the granulites of the KU against the lower grade rocks of the Abitibi greenstone belt (AGB) along the Ivanhoe Lake fault zone is problematic. To constrain the postmetamorphic tectonothermal history of the KU, we have conducted 57 40Ar/39Ar step-heating analyses on mineral and rock samples collected in a transect across the southern KU and adjacent AGB. The age spectra record a complex thermal history. Amphiboles from the AGB in the footwall of the Ivanhoe Lake fault zone have ca. 2.66 Ga dates, similar to closure ages for amphiboles from farther east in the AGB. Amphibole dates of 2.46–2.52 Ga from the deepest structural levels of the KU place an upper limit on the time of major uplift of the granulites and their juxtaposition with the AGB. Biotite and muscovite dates from the transect cluster into three age groups. The presence in the deepest structural levels of the KU of biotite with 2.40–2.45 Ga dates indicates that significant uplift (15–20 km or more) of the granulites had occurred by this time. Micas with dates in the 2.25–2.30 Ga range are close to fault zones; these dates may indicate a ca. 2.30 Ga episode of fault reactivation. Feldspar, fault-related whole rocks, and some micas record events post 2.1 Ga. These correspond to the emplacement of mafic and lamprophyric dykes and fault reactivation.

scholarly journals North Atlantic marine biogenic silica accumulation through the early to middle Paleogene: implications for ocean circulation and silicate weathering feedback

2021 ◽  
Vol 17 (5) ◽  
pp. 1937-1954
Author(s):  
Jakub Witkowski ◽  
Karolina Bryłka ◽  
Steven M. Bohaty ◽  
Elżbieta Mydłowska ◽  
Donald E. Penman ◽  
...  
Keyword(s):  
North Atlantic ◽  
Biogenic Silica ◽  
Middle Eocene ◽  
Nutrient Supply ◽  
Late Eocene ◽  
Silicate Weathering ◽  
Early Eocene ◽  
The North ◽  
History Of ◽  
The North Atlantic

Abstract. The Paleogene history of biogenic opal accumulation in the North Atlantic provides insight into both the evolution of deepwater circulation in the Atlantic basin and weathering responses to major climate shifts. However, existing records are compromised by low temporal resolution and/or stratigraphic discontinuities. In order to address this problem, we present a multi-site, high-resolution record of biogenic silica (bioSiO2) accumulation from Blake Nose (ODP Leg 171B, western North Atlantic) spanning the early Paleocene to late Eocene time interval (∼65–34 Ma). This record represents the longest single-locality history of marine bioSiO2 burial compiled to date and offers a unique perspective into changes in bioSiO2 fluxes through the early to middle Paleogene extreme greenhouse interval and the subsequent period of long-term cooling. Blake Nose bioSiO2 fluxes display prominent fluctuations that we attribute to variations in sub-thermocline nutrient supply via cyclonic eddies associated with the Gulf Stream. Following elevated and pulsed bioSiO2 accumulation through the Paleocene to early Eocene greenhouse interval, a prolonged interval of markedly elevated bioSiO2 flux in the middle Eocene between ∼46 and 42 Ma is proposed to reflect nutrient enrichment at Blake Nose due to invigorated overturning circulation following an early onset of Northern Component Water export from the Norwegian–Greenland Sea at ∼49 Ma. Reduced bioSiO2 flux in the North Atlantic, in combination with increased bioSiO2 flux documented in existing records from the equatorial Pacific between ∼42 and 38 Ma, is interpreted to indicate diminished nutrient supply and reduced biosiliceous productivity at Blake Nose in response to weakening of the overturning circulation. Subsequently, in the late Eocene, a deepwater circulation regime favoring limited bioSiO2 burial in the Atlantic and enhanced bioSiO2 burial in the Pacific was established after ∼38 Ma, likely in conjunction with re-invigoration of deepwater export from the North Atlantic. We also observe that Blake Nose bioSiO2 fluxes through the middle Eocene cooling interval (∼48 to 34 Ma) are similar to or higher than background fluxes throughout the late Paleocene–early Eocene interval (∼65 to 48 Ma) of intense greenhouse warmth. This observation is consistent with a temporally variable rather than constant silicate weathering feedback strength model for the Paleogene, which would instead predict that marine bioSiO2 burial should peak during periods of extreme warming.

scholarly journals STRUCTURAL STYLE AND DEPOSITIONAL HISTORY OF THE SEMANGKO PULL APART BASIN IN THE SOUTHEASTERN SEGMENT OF SUMATRA FAULT ZONE

2018 ◽  
Vol 28 (1) ◽  
pp. 115
Author(s):  
Maruf M Mukti
Keyword(s):  
Fault Zone ◽  
Seismic Data ◽  
Side Wall ◽  
Depositional History ◽  
Structural Style ◽  
Pull Apart Basin ◽  
History Of ◽  
Step Over ◽  
Structural High

Re-examination of published seismic data in the southeasternmost segment of the active Sumatra Fault zone (SFZ) reveals the characteristics of structural style and depositional history of Semangko pull apart basin (SPB). The SPB have been developed as a transtensional pull apart basin resulted from stepping over of the Semangko to Ujung Kulon segments of the SFZ. The geometry of SPB is of rhomboidal shape characterized by dual depocenters separated by a discrete structural high in the center of SPB. Based on the determination of pre- and syn-kinematic strata related to the formation of SPB, sedimentary units prior to deposition of Unit 3 can be regarded as pre-kinematic strata, whereas the syn-kinematic strata is represented by Unit 3. The basin sidewall faults of the SPB are likely to have been developed as en-echelon side wall faults and identified as the East Semangko Fault (ESF) and Kota Agung – South Panaitan Faults (KAF-SPF) in the western and eastern margin of the SPB, respectively. The development of discrete highs along the center of the SPB may relate to the formation of en-echelon cross-basin faults that are now overprinted by volcanic activity or magmatic intrusion.Analisa ulang data seismik yang telah dipublikasikan di daerah segmen paling tenggara dari zona sesar aktif Sumatra (SFZ) mengungkapkan karakteristik struktur dan sejarah pengendapan dari cekungan pull-apart Semangko (SPB). SPB terbentuk sebagai cekungan transtensional pull-apart yang dihasilkan dari step over segmen Semangko dan segmen Ujung Kulon. Geometri SPB adalah bentuk rhomboidal yang dicirikan oleh dua depocenter yang dipisahkan oleh struktur tinggian yang tidak menerus di bagian tengah SPB. Berdasarkan penentuan unit pre- dan syn-kinematic strata yang terkait dengan pembentukan SPB, unit sedimen yang terbentuk sebelum pengendapan Unit 3 dapat dianggap sebagai pre-kinematic strata, sedangkan syn-kinematic strata diwakili oleh Unit 3. Sesar side-wall dari SPB kemungkinan telah berkembang sebagai sesar yang bersifat en-echelon dan diidentifikasi sebagai Sesar Semangko Timur (ESF) dan Sesar Kota Agung - Panaitan Selatan (KAF-SPF) di tepian barat dan timur SPB. Pembentukan tinggian  yang tidak menerus di sepanjang bagian tengah SPB berhubungan dengan pembentukan sesar-sesar cross-basin yang bersifat en-echelon yang sekarang telah tertutupi jejaknya oleh aktivitas gunung api atau intrusi magmatik. 

scholarly journals Fluid Inclusions Record Hydrocarbon Charge History in the Shunbei Area, Tarim Basin, NW China

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Ziye Lu ◽  
Yingtao Li ◽  
Ning Ye ◽  
Shaonan Zhang ◽  
Chaojin Lu ◽  
...  
Keyword(s):  
Fault Zone ◽  
Fluid Inclusions ◽  
Tarim Basin ◽  
Homogenization Temperature ◽  
Fault Zones ◽  
Carbonate Reservoirs ◽  
Fault System ◽  
Middle Ordovician ◽  
History Of ◽  
Hydrocarbon Charge

The exploration of deeply buried hydrocarbon is still a challenge for the petroleum geology. The Shunbei area is a newly discovered oil fields, located in the center of the Tarim Basin. The oil is mainly yielded from the Middle–Lower Ordovician carbonate reservoirs with depth > 7000  m in the Shunbei No. 1 and No. 5 fault zones. Calcite cements filled in vugs (v-calcite) and fractures (f-calcite) are identified in limestones and dolostones of the carbonate reservoirs. F-calcites in the Shunbei No. 1 fault zone trap secondary inclusions in trails, which comprise liquid-dominated biphase aqueous inclusions, liquid-dominated biphase oil inclusions, and/or oil-bearing triphase inclusions. F-calcite and v-calcite in the No. 5 fault zone trap secondary inclusions in trails, which consist of liquid-only monophase aqueous inclusions, liquid-dominated biphase aqueous inclusions, liquid-dominated biphase oil inclusions, liquid-only monophase oil inclusions, and/or oil-bearing triphase inclusions. The ranges of the homogenization temperature ( T h ) and ice-melting temperature ( T m − ice ) in the Shunbei No. 1 fault zone are, respectively, 130–150°C and -2.1–-1.5°C. The coexistence of liquid-only and liquid-dominated aqueous inclusions in the Shunbei No. 5 fault zone indicates that the aqueous inclusions are trapped at low temperatures. The aqueous inclusions in the Shunbei No. 5 fault zone show a range from -0.4 to -0.2°C in T m − ice which is very close to the meteoric fluid. In the context of the burial-thermal history and the Cambrian source rock evolution, the charging process of hydrocarbon in the Shunbei No. 1 and No. 5 fault zones corresponds to the Silurian and Middle Ordovician, respectively. Results of fluid inclusions indicate a tightly coupling relationship between the hydrocarbon charging process and fault system evolution in the Shunbei area. This study reveals the application of fluid inclusion under the systemically petrographic constraints to decipher the charging history of hydrocarbon, especially for the deeply buried reservoirs.

scholarly journals Burial and exhumation history of the Jameson Land Basin, East Greenland, estimated from thermochronological data from the Blokelv-1 core

2018 ◽  
pp. 133-147
Author(s):  
Paul F. Green ◽  
Peter Japsen
Keyword(s):  
Middle Eocene ◽  
Vitrinite Reflectance ◽  
Upper Jurassic ◽  
Late Eocene ◽  
Early Eocene ◽  
Ocean Drilling Program ◽  
East Greenland ◽  
Ocean Drilling ◽  
History Of ◽  
Intrusive Activity

Apatite fission-track analysis (AFTA) data in two Upper Jurassic core samples from the 231 m deep Blokelv-1 borehole, Jameson Land, East Greenland, combined with vitrinite reflectance data and regional AFTA data, define three palaeo-thermal episodes. We interpret localised early Eocene (55– 50 Ma) palaeotemperatures as representing localised early Eocene heating related to intrusive activity whereas we interpret late Eocene (40–35 Ma) and late Miocene (c. 10 Ma) palaeotemperatures as representing deeper burial followed by successive episodes of exhumation. For a palaeogeothermal gradient of 30°C/km and likely palaeo-surface temperatures, the late Eocene palaeotemperatures require that the Upper Jurassic marine section in the borehole was buried below a 2750 m thick cover of Upper Jurassic – Eocene rocks prior to the onset of late Eocene exhumation. As these sediments are now near outcrop at c. 200 m above sea level, they have been uplifted by at least 3 km since maximum burial during post-rift thermal subsidence. The results are consistent with estimates of rock uplift on Milne Land since the late Eocene and with interpretation of Ocean Drilling Program (ODP) data off South-East Greenland suggesting that mid-Cenozoic uplift of the margin triggered the marked influx of coarse clastic turbidites during the late Oligocene above a middle Eocene to upper Oligocene hiatus.

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