Despite the growing concern regarding post-mineralization thermo-tectonic processes in recent years,the relative roles in exhuming and preserving ore deposits remain highly controversial.This study presents new apatit...Despite the growing concern regarding post-mineralization thermo-tectonic processes in recent years,the relative roles in exhuming and preserving ore deposits remain highly controversial.This study presents new apatite fission track and(U-Th)/He data from the Xishimen iron skarn deposit in the Handan-Xingtai district,central North China Craton.Apatite fission track dating yielded central ages ranging from 88±18 Ma to 125±9 Ma,with mean confined track lengths varying between 11.9±0.4μm and 13.3±0.2μm.Integrated apatite(U-Th)/He dating provided ages of 42.5±0.8 Ma to 48.1±3.3 Ma.Our new data,combined with previous zircon U-Pb and potassium-bearing mineral^(40)Ar/^(39)Ar ages,revealed three cooling episodes:very rapid cooling(100–140℃/Ma)at ca.130–120 Ma,a protracted slow cooling period(0.2–0.4℃/Ma)at ca.120–50 Ma,and moderate cooling(0.8–1.0℃/Ma)since ca.50 Ma.The initial rapid cooling phase was primarily attributed to post-magmatic thermal equilibration following the shallow emplacement of the Xishimen deposit.The subsequent cooling phases were controlled by uplift and exhumation processes.Our thermal models indicate an estimated total unroofing thickness of<3 km,which is shallower than the emplacement depth of the ore deposit(3–5 km).This suggests significant potential for mineral exploration.Furthermore,a comprehensive review of preservation mechanisms for various ore deposits underscores the significant role of tectonics in both exhuming and preserving ore bodies.展开更多
Phlogopiie-and diopside-bearing dunite occurs as rounded inclusions in hornblende-diorite. Thepetrofabrics, mineral composition and abundances of the trace elements in the dunite indicate that the inclu-sions were der...Phlogopiie-and diopside-bearing dunite occurs as rounded inclusions in hornblende-diorite. Thepetrofabrics, mineral composition and abundances of the trace elements in the dunite indicate that the inclu-sions were derived from the upper mantle and are the residues of high-degree partial melting of mantlepeirdotite. The study of trace elements in the inclusions and their host rocks shows that the magma was origi-nated from the mantle which was enriched in incompatible elements by mantle metasomatism prior to the par-tial melting.展开更多
基金supported by the Open Project Program of Hebei Province Collaborative Innovation Center for Strategic Critical Mineral Research,Hebei GEO University,China(No.HGUXT-2023-14)the China Geological Survey(DD20221646)+1 种基金National Natural Science Foundation of Hebei Province(Nos.D2020402013 and D2023402022)National Natural Science Foundation of China(No.42102091).
文摘Despite the growing concern regarding post-mineralization thermo-tectonic processes in recent years,the relative roles in exhuming and preserving ore deposits remain highly controversial.This study presents new apatite fission track and(U-Th)/He data from the Xishimen iron skarn deposit in the Handan-Xingtai district,central North China Craton.Apatite fission track dating yielded central ages ranging from 88±18 Ma to 125±9 Ma,with mean confined track lengths varying between 11.9±0.4μm and 13.3±0.2μm.Integrated apatite(U-Th)/He dating provided ages of 42.5±0.8 Ma to 48.1±3.3 Ma.Our new data,combined with previous zircon U-Pb and potassium-bearing mineral^(40)Ar/^(39)Ar ages,revealed three cooling episodes:very rapid cooling(100–140℃/Ma)at ca.130–120 Ma,a protracted slow cooling period(0.2–0.4℃/Ma)at ca.120–50 Ma,and moderate cooling(0.8–1.0℃/Ma)since ca.50 Ma.The initial rapid cooling phase was primarily attributed to post-magmatic thermal equilibration following the shallow emplacement of the Xishimen deposit.The subsequent cooling phases were controlled by uplift and exhumation processes.Our thermal models indicate an estimated total unroofing thickness of<3 km,which is shallower than the emplacement depth of the ore deposit(3–5 km).This suggests significant potential for mineral exploration.Furthermore,a comprehensive review of preservation mechanisms for various ore deposits underscores the significant role of tectonics in both exhuming and preserving ore bodies.
文摘Phlogopiie-and diopside-bearing dunite occurs as rounded inclusions in hornblende-diorite. Thepetrofabrics, mineral composition and abundances of the trace elements in the dunite indicate that the inclu-sions were derived from the upper mantle and are the residues of high-degree partial melting of mantlepeirdotite. The study of trace elements in the inclusions and their host rocks shows that the magma was origi-nated from the mantle which was enriched in incompatible elements by mantle metasomatism prior to the par-tial melting.
