The strength of the lower continental crust; evidence from the Stillwell Hills-Oygarden Group Coastline.

• Other Authors: CLARKE, GEOFFREY L (hasPrincipalInvestigator), HALPIN, JACQUELINE (hasPrincipalInvestigator), HALPIN, JACQUELINE (processor), University of Sydney (originator), Australian Antarctic Data Centre (publisher)
• Format: Dataset
• Language: unknown
• Published: Australian Antarctic Data Centre
• Subjects: geoscientificInformation; BEDROCK LITHOLOGY; EARTH SCIENCE; SOLID EARTH; ROCKS/MINERALS/CRYSTALS; METAMORPHIC ROCKS; MINERALS; FAULT MOVEMENT; TECTONICS; PLATE TECTONICS; FOLDS; STRESS; LITHOSPHERIC PLATE MOTION; ASSEMBLAGE; BROKA-HAVSTEIN; COLLECTOR; DATE; DESCRIPTION; EAST ANTARCTICA; FOLIATION; GONDWANA; HIGH TEMPERATURE; KEMP LAND; LATITUDE; LINEATION; LONGITUDE; LOWER CRUST; OYGARDEN ISLANDS; PROTEROZOIC; PURPOSE; RAYNER; ROCK TYPE; SAMPLE NUMBER; SITE; STILLWELL HILLS; FIELD SURVEYS; FIELD INVESTIGATION; CONTINENT > ANTARCTICA > Oygarden Group; Broka-Havstein Island; Mawson; GEOGRAPHIC REGION > POLAR; Broka; East Antarctica; Havstein; Havstein Island; Kemp Land; Oygarden; Prince Charles Mountains; Rayner; Stillwell Hills; Antarc*; Antarctica
• Online Access: https://researchdata.ands.org.au/strength-lower-continental-group-coastline/699462; https://doi.org/10.4225/15/54DAC65B23A41; https://data.aad.gov.au/metadata/records/ASAC_1150

The nature of the data were lithological and structural geological mapping, in addition to the collection of relevant geological specimens. The quality of the data collected ranges from detailed form surface mapping in the Oygarden Islands and locally in the Broka-Havstein and Stillwell Hills areas, to regional mapping in the majority of the latter two regions. The main episode of the high grade deformation preserved in the area occurred during the c.950Ma Rayner Structural Episode, a collisional event which affected large areas of Enderby, Kemp, MacRoberston Lands and the northern Prince Charles Mountains. In the Oygardens this deformation occurred in the middle to lower crustal levels, while the section through the Broka-Havstein, through to the Stillwell Hills, is thought to represent a continuation of this crustal section as a tilted crustal block, moving stratigraphically higher towards the Stillwell Hills. Work in the Oygarden Group has shown that at these deep crustal levels, lithology can be heterogeneous, and deformation varied, which opposes conventional ideas of lithological and rheological homogeneity, and a constant deformation style. With movement eastwards to the Stillwell Hills this work revealed differences in deformation style as one moves through the crustal levels, with deformation dominated by a more homogeneous deformation style of superposed penetrative deformation events. Geological samples will be used to constrain the nature of the mineral assemblages and fluid present during metamorphism, as well as study on the pressures and temperatures of metamorphism, and the phase relationships which developed throughout the metamorphic evolution of the belt. 2008 In May of 2008, two new files were added to the dataset - a pdf copy of the original field notes taken in the Stillwell Hills during the project (SWHfieldbook2002_Halpin1.pdf), plus a new excel spreadsheet which is an attempt to bring together all the Stillwell Hills spreadsheets in the dataset (Halpin_StillwellHills_FieldData.xls). 2009 In March of 2009, the excel spreadsheet, Halpin_StillwellHills_FieldData.xls, was replaced by a series of shapefiles (in the folder StillwellHills_FieldData). The shapefile of the field sites data contains the following fields: SITE: Individual site number/reference for location - corresponds to original hand-drawn maps and entries in the geologist's notebook. OBS: Unique observation identification tag related to the SITE number - there may be several OBS entries for a single SITE, which may include several descriptions of rock types, measurements etc. SAMPLE: Sample number if a sample was collected. GEOLOGIST: The name of the geologist that recorded the observation/sample/measurement etc. DATE_: The date of the recorded observation/sample/measurement etc. ROCK_TYPE: Lithology type at the specified location DESCR: Description of lithology type/mineralogy/sample/structural information etc. FOLIATION: Inferred foliation type/generation (where S1=first generation foliation related to D1 deformation, S2=second generation foliation related to D2 deformation, S2/3= transposition of S2 foliation during D3 deformation etc, AP=axial plane. STRIKE: Strike/trend of foliation (measured from north) in degrees. DIP: Dip of foliation (measured from horizontal) in degrees. DIP_DIR: Dip direction of foliation, allows DIP to be a unique direction. LINEATION: Inferred lineation or fold axis generation (where L1=first generation lineation related to D1 deformation, L2=second generation lineation related to D2 deformation, L2/3= transposition of L2 lineation during D3 deformation etc, F1=first generation fold axis related to D1 deformation, F2=second generation fold axis related to D2 deformation, F2/3= transposition of F2 fold axis during D3 deformation etc.) PLUNGE: Plunge of the lineation/fold axis (measured from horizontal) in degrees. PLUNGE_DIR: Plunge/trend direction of the lineation/fold axis (measured from north) in degrees. The data for this project is the same as that for ASAC_2214. The fields in this dataset are: Site Sample Number Collector/Geologist Date Latitude Longitude Rock Type Assemblage Description (Desc) Purpose Foliation Lineation (L) Strike Dip Dip direction Plunge Plunge direction The mineral assemblage code abbreviations are as follows: Grt= garnet Ksp= alkali feldspar Pl (or plag)= plagioclase Q= quartz Cpx= clinopyroxene Opx=orthopyroxene Px=pyroxene Bi= biotite Sill=sillimanite Musc= muscovite Mag=magnetite Cd=cordierite Amph= amphibole Hbl=hornblende The foliation codes begin with an 'S' which just means the measurement is a foliation, and then is followed by a number to indicate which deformation event the foliation records, hence S1, S2, S3 etc. The lineation data are much the same however they begin with an 'L' followed by a number.