scholarly journals Petrophysical Properties (Density and Magnetization) of Rocks from the Suhbaatar-Ulaanbaatar-Dalandzadgad Geophysical Profile in Mongolia and Their Implications

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Tao Yang ◽  
Jintian Gao ◽  
Zuowen Gu ◽  
Baatarkhuu Dagva ◽  
Batsaikhan Tserenpil
Keyword(s):  
Magnetic Susceptibility ◽  
Remanent Magnetization ◽  
Ground Surface ◽  
Gravity Anomalies ◽  
Magnetic Anomalies ◽  
Natural Remanent Magnetization ◽  
Petrophysical Properties ◽  
Geological History ◽  
Essential Information ◽  
Variable Gravity

Petrophysical properties of 585 rock samples from the Suhbaatar-Ulaanbaatar-Dalandzadgad geophysical profile in Mongolia are presented. Based on the rock classifications and tectonic units, petrophysical parameters (bulk density, magnetic susceptibility, intensity of natural remanent magnetization, and Köenigsberger ratio) of these rocks are summarized. Results indicate that (1) significant density contrast of different rocks would result in variable gravity anomalies along the profile; (2) magnetic susceptibility and natural remanent magnetization of all rocks are variable, covering 5-6 orders of magnitude, which would make a variable induced magnetization and further links to complex magnetic anomalies in ground surface; (3) the distribution of rocks with different lithologies controls the pattern of lithospheric magnetic anomaly along the profile. The petrophysical database thus provides not only one of the keys to understand the geological history and structure of the profile, but also essential information for analysis and interpretation of the geophysical (e.g., magnetic and gravity) survey data.

Multi-proxy study of the Cretaceous-Paleogene (K-Pg) boundary in deep-sea turbiditic sediments in the Uzgruň section (Outer Flysch Carpathians, Czech Republic)

2021 ◽  
Author(s):  
Šimon Kdýr ◽  
Tiiu Elbra ◽  
Miroslav Bubík ◽  
Petr Schnabl ◽  
Lilian Švábenická
Keyword(s):  
Magnetic Susceptibility ◽  
Czech Republic ◽  
Detection Limit ◽  
Remanent Magnetization ◽  
Magnetic Particles ◽  
Principal Component ◽  
Natural Remanent Magnetization ◽  
Ongoing Research ◽  
Small Stream ◽  
Magnetic Methods

<p>The composite profile, with 4 studied sections, is located near the Uzgruň village (Czech Republic) next to a small stream. The profile is composed of Late Maastrichtian to Palaeocene flysch sediments and the K-Pg boundary is set in claystones within this turbiditic setting. Ongoing research of local paleoenvironment and stratigraphy is based on paleo- and rock-magnetic methods, micropaleontology and geochemistry to obtain more detailed view of the local situation during the K-Pg extinction event. Based on biostratigraphy, two dinocyst zones (Bubík et al., 2002): Palynodium grallator and Carpatella cornuta (first occurrence in the Danian), two calcareous nannofossil zones in the Upper Maastrichtian, and the agglutinated foraminifer zone Rzehakina fissistomata in the Paleogene were distinguished. Biostratigraphic data support the K-Pg boundary interval. The uppermost Maastrichtian is indicated by nannofossil species Micula prinsii, UC26d<sup>TP</sup> zone. Basal Paleogene non-calcareous strata contain dinocyst Carpatella cornuta and agglutinated foraminifers of Rzehakina fissistomata zone. The presence of low-latitude nannofossil taxa M. prinsii and Ceratolithoides kamptneri show input of warm waters during the uppermost Maastrichtian. Several rock-magnetic methods, such as acquisition of Isothermal remanent magnetization (IRM), acquisition of Anhysteretic remanent magnetization (ARM), Anisotropy of magnetic susceptibility (AMS), Field dependence of magnetic susceptibility (HD) and Frequency dependence of magnetic susceptibility (FD), were applied to estimate behaviour and origin of magnetic particles. Natural remanent magnetization (NRM) values of samples range from 0.09 to 2.48 mA/m. Volume normalized magnetic susceptibility (MS) show values from 130 up to 1197 SI*10-6. There is no increase observed in MS across stratigraphic boundary due to turbiditic evolution of sediment. Due to character of sediments, we applied alternating field (AF) demagnetization and used principal component analysis (PCA; Kirschvink, 1980) for estimation of characteristic remanent component. Most of the K/Pg sections worldwide have well documented Iridium anomaly. In Uzgruň, the preliminary results show that although the values are not as pronounced, the Ir at K-Pg boundary is still higher than in surrounding sediments. For tracing of Deccan traps effect we plan to apply mercury (Hg)/total organic carbon (TOC) stratigraphy. TOC content of 20 pilot samples is low, but not under detection limit of the instrumentation (mean value 0.92 wt%). One sample reached value 4.41 wt% of TOC. Sulphur contents are reaching 1 wt%, but several samples were under detection limit of the instrumentation. Sulphur concentrations suggest more reduction conditions of burial.</p><p>Current research is supported by Czech Science Foundation project no. 19-07516S and is in accordance with research plan no. RVO67985831.</p><p>Bubík, M., Adamová, M., Bąk, M., Franců, J., Gedl, P., Mikuláš, R., Švábenická, L., & Uchman, A. (2002). Výsledky výzkumu hranice křída/terciér v magurském flyši u Uzgruně. Geologické výzkumy na Moravě a ve Slezsku, 9, 18–22</p><p>L. Kirschvink (1980), The least-squares line and plane and the analysis of palaeomagnetic data, Geophysical Journal International, 62(3), 699–718, https://doi.org/10.1111/j.1365-246X.1980.tb02601.x</p>

scholarly journals A survey of the natural remanent magnetization and magnetic susceptibility of Apollo whole rocks

2019 ◽  
Vol 290 ◽  
pp. 36-43 ◽  
Author(s):  
Camille Lepaulard ◽  
Jérôme Gattacceca ◽  
Minoru Uehara ◽  
Pierre Rochette ◽  
Yoann Quesnel ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Remanent Magnetization ◽  
Natural Remanent Magnetization

The IDQ curve: A tool for evaluating the direction of remanent magnetization from magnetic anomalies

Geophysics ◽  
2020 ◽  
Vol 85 (5) ◽  
pp. J85-J98
Author(s):  
Shuang Liu ◽  
Xiangyun Hu ◽  
Dalian Zhang ◽  
Bangshun Wei ◽  
Meixia Geng ◽  
...  
Keyword(s):  
Remanent Magnetization ◽  
Field Data ◽  
Eastern China ◽  
Synthetic Data ◽  
Magnetic Anomalies ◽  
Natural Remanent Magnetization ◽  
Magma Intrusion ◽  
Magnetization Direction ◽  
Ore Bodies ◽  
Using Data

Natural remanent magnetization acts as a record of the previous orientations of the earth’s magnetic field, and it is an important feature when studying geologic phenomena. The so-called IDQ curve is used to describe the relationship between the inclination ( I) and declination ( D) of remanent magnetization and the Köenigsberger ratio ( Q). Here, we construct the IDQ curve using data on ground and airborne magnetic anomalies. The curve is devised using modified approaches for estimating the total magnetization direction, e.g., identifying the maximal position of minimal reduced-to-the-pole fields or identifying correlations between total and vertical reduced-to-the-pole field gradients. The method is tested using synthetic data, and the results indicate that the IDQ curve can provide valuable information on the remanent magnetization direction based on available data on the Köenigsberger ratio. Then, the method is used to interpret field data from the Yeshan region in eastern China, where ground anomalies have been produced by igneous rocks, including diorite and basalt, which occur along with magnetite and hematite ore bodies. The IDQ curves for 24 subanomalies are constructed, and these curves indicate two main distribution clusters of remanent magnetization directions corresponding to different structural units of magma intrusion and help identify the lithologies of the magnetic sources in areas covered by Quaternary sediments. The estimated remanent magnetization directions for Cenozoic basalt are consistent with measurements made in paleomagnetism studies. The synthetic and field data indicate that the IDQ curve can be used to efficiently estimate the remanent magnetization direction from a magnetic anomaly, which could help with our understanding of geologic processes in an area.

scholarly journals Application of the pseudo-Thellier technique to a paleomagnetic record from lake El Trébol (Patagonia, Argentina)

2008 ◽  
Vol 47 (4) ◽  
pp. 319-327
Author(s):  
C. S. G. Gogorza ◽  
S. Torcida ◽  
A. M. Sinito ◽  
M. A. E. Chaparro
Keyword(s):  
Magnetic Susceptibility ◽  
Error Estimates ◽  
Sediment Core ◽  
Standard Method ◽  
Remanent Magnetization ◽  
Reasonable Agreement ◽  
Natural Remanent Magnetization ◽  
Isothermal Remanent Magnetization ◽  
Low Field ◽  
Relative Paleointensity

The pseudo-Thellier technique was applied to obtain relative paleointensity determinations using a sediment core from Lake El Tre?bol (Patagonia, Argentina). Measurements of intensity of natural remanent magnetization left (NRMleft) after AF demagnetization versus intensity of anhysteric remanent magnetization gained (ARMgained) at the same peak were carried out on a set of samples. Two versions of a jackknife resampling scheme were used to get error estimates on the paleointensity. The pseudo-Thellier paleointensity records were compared with the authors previous results where the remanent magne- tization at 20mT (NRM20mT) has been normalized using the anhysteric remanent magnetization at 20mT (ARM20mT), the satu- ration of the isothermal remanent magnetization at 20mT (SIRM20mT) and the low field magnetic susceptibility (k) (Gogorza et al., 2006). The pseudo-Thellier record shows a reasonable agreement with the standard method of normalization (NRM20mT/ ARM20mT).

New constraints on the role of late Variscan extension in the origin of the Eastern Galicia Magnetic Anomaly (NW Spain)

2020 ◽  
Author(s):  
Puy Ayarza ◽  
Juan José Villalaín ◽  
Jose Ramón Martínez Catalán ◽  
Fernando Alvarez Lobato ◽  
Manuela Durán Oreja ◽  
...  
Keyword(s):  
Magnetic Anomaly ◽  
Remanent Magnetization ◽  
Magnetic Anomalies ◽  
Natural Remanent Magnetization ◽  
Source Rocks ◽  
Magmatic Rocks ◽  
Extensional Tectonic ◽  
Tectonic Window ◽  
Central Iberian Arc

<p><span lang="EN-US">The Eastern Galicia Magnetic Anomaly (EGMA) is one of the most conspicuous and, definitively, the best studied of all the magnetic anomalies in the Central Iberian Arc (CIA). This is probably due to its location, on the thoroughly researched Lugo-Sanabria gneiss dome and to the unique fact that its source rocks crop out in the Xistral Tectonic Window. Multiple studies and models of this anomaly have been carried out in the last 25 years and still, new results keep on shedding more light on its understanding. Rock magnetic analyses, natural remanent magnetization, anisotropy of the magnetic susceptibility and stable isotopes geochemistry carried out on the rocks that produce this anomaly have provided new insights on the processes that led to magnetization and on its age. Results suggest that magnetization of source rocks is a consequence of the increase in oxygen fugacity underwent by metamorphic and magmatic rocks affected by late-Variscan extensional tectonics. Extensional detachments were the pathways that allowed the entrance of fluids that led to syn-tectonic crystallization of magnetite and hematite in S-Type granites. Accordingly, magnetization is not really linked to primary lithologies but mostly to extensional structures. This process took place in the late Carboniferous to earliest Permian, during the Kiaman reverse superchron. Natural remanent magnetization exhibited by hematite-bearing samples confirms the age of the magnetization and adds complexity to the interpretation of the EGMA, where remanence has been often largely ignored or underestimated. Understanding the origin of the EGMA contributes to the interpretation of other anomalies existing in the CIA, also located on thermal domes. Furthermore, it provides new hints to interpret magnetic anomalies located in extensional tectonic contexts worldwide</span></p>

Archaeomagnetism and magnetic anomalies in the American Southwest

Geophysics ◽  
1987 ◽  
Vol 52 (3) ◽  
pp. 368-371 ◽  
Author(s):  
Robert S. Sternberg
Keyword(s):  
Magnetic Susceptibility ◽  
Magnetic Induction ◽  
Remanent Magnetization ◽  
Magnetic Anomalies ◽  
American Southwest ◽  
Archaeological Sites ◽  
Thermoremanent Magnetization ◽  
Disturbed Soil ◽  
Magnetic Remanence ◽  
Geophysical Technique

Magnetic surveying is probably the most widely used geophysical technique at archaeological sites (Weymouth and Huggins, 1985). It is useful for locating features in which the magnetic susceptibility contrasts with the magnetic susceptibility of the surroundings because of induced and/or remanent magnetization. A contrast in magnetic induction can arise, for example, when the disturbed soil fill inside a formerly occupied room has a different magnetic susceptibility from the subsoil outside the room (Tite and Mullins, 1971). A contrast in magnetic remanence most commonly occurs when a baked clay artifact or feature such as a hearth has acquired a thermoremanent magnetization after being heated to several hundred degrees Celsius.

REMANENT MAGNETIZATION FROM COMPARISON OF GRAVITY AND MAGNETIC ANOMALIES

Geophysics ◽  
1976 ◽  
Vol 41 (1) ◽  
pp. 56-61 ◽  
Author(s):  
D. H. Shurbet ◽  
G. R. Keller ◽  
J. P. Friess
Keyword(s):  
Remanent Magnetization ◽  
Spatial Relationship ◽  
Gravity Anomalies ◽  
Magnetic Anomalies ◽  
The Body ◽  
Gravity And Magnetic

Gravity and magnetic anomalies caused by deeply buried rock bodies in northwest Texas are compared. Interpretation of the gravity anomalies by modeling is used to locate and define the geometry of the body in a way analogous to the use of bathymetry in studies concerned with magnetization of seamounts. The direction of magnetization is then determined from the spatial relationship between the gravity and magnetic anomalies. This procedure amounts to an in‐situ determination of direction of magnetization of the body. In one example direction of magnetization indicates the time of intrusion and in another it indicates regional heating since intrusion.

The Mid-Atlantic ridge near 45° N. VII. Magnetic properties and opaque mineralogy of dredged samples

1970 ◽  
Vol 7 (2) ◽  
pp. 239-256 ◽  
Author(s):  
C. M. Carmichael
Keyword(s):  
Magnetic Properties ◽  
Remanent Magnetization ◽  
Complex Structure ◽  
Magnetic Anomalies ◽  
Natural Remanent Magnetization ◽  
Coarse Grained ◽  
X Ray Diffraction ◽  
Field Polarity ◽  
Fine Grained ◽  
Mid Atlantic Ridge

Measurements of the magnetic properties, paleomagnetic field intensity, and the inferred paleomagnetic field polarity have been made using fine grained basalt and coarser grained rock samples dredged from the mid-Atlantic ridge near 45° N and supplied by the Geological Survey of Canada. The opaque mineralogy of the samples was studied by microscope, Curie point, and X-ray diffraction techniques. The natural remanent magnetization of the basalt is of the order of 5 to 10 × 10−3 e.m.u./cm3 with some values from the center of the median valley reaching 10−1 e.m.u./cm3. Magnetic anomalies over the ridge can be accounted for by the remanent magnetization of a few hundred meters of this basalt. The coarse grained rocks were relatively weakly magnetized, and while they contribute little to the magnetic anomalies, their diverse character suggests that the major portion of the oceanic crust, below a thin veneer of fine grained basalt, has differentiated into a complex structure.

scholarly journals Obsidians of Pantelleria (Strait of Sicily): A Petrographic, Geochemical and Magnetic Study of Known and New Geological Sources

2020 ◽  
Vol 6 (1) ◽  
pp. 434-453 ◽  
Author(s):  
Silvio G. Rotolo ◽  
Maria Luisa Carapezza ◽  
Alessandra Correale ◽  
Franco Foresta Martin ◽  
Gregor Hahn ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Bronze Age ◽  
Remanent Magnetization ◽  
Analytical Approach ◽  
Major Element ◽  
Natural Remanent Magnetization ◽  
Strait Of Sicily ◽  
Magnetic Methods ◽  
Icp Ms ◽  
Ft Ir

Abstract This paper provides new petrochemical and paleomagnetic data from obsidian sub-sources on the island of Pantelleria, exploited since the Neolithic. Data has been obtained from 14 obsidian samples from 4 locations: Fossa della Pernice (2 sites), Salto la Vecchia and Balata dei Turchi. Here, we aim to better characterize these obsidians using a cross-disciplinary and multi-analytical approach, to further understand their archaeological significance. Major element analyses (EMP) have enabled two compositional super-groups to be distinguished: (i) Fossa della Pernice, less peralkaline and (ii) Balata dei Turchi–Salto la Vecchia, distinctly more peralkaline and having almost identical chemical patterns. Trace element analyses (LA-ICP-MS) corroborate major element groupings, with the Balata dei Turchi–Salto la Vecchia super-group being further characterized by a pronounced negative europium anomaly. Glass H2O contents (FT-IR) reveal an overlap among all the sub-sources (H2O = 0.1–0.3 wt. %). Magnetic methods have refined the petrochemical groupings, permitting further distinction between Balata dei Turchi–Salto La Vecchia and the Fossa della Pernice super-groups. The occurrence of sub-microscopic (< 1 μm) ferromagnetic minerals results in different magnetic susceptibility and Natural Remanent Magnetization values and allows the best distinction among the products from the chosen sites. When compared with obsidian tools excavated from Bronze-age settlements on the island of Ustica (230 km NE of Pantelleria), 12% are distinctly peralkaline, indicating their provenance to be from the Balata dei Turchi sub-source.

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